iForest - Biogeosciences and Forestry

Research Articles: Deploying an early-stage Cyber-Physical System for the implementation of Forestry 4.0 in a New Zealand timber harvesting context

Humphrey P, Harvey C, Visser R — 2024-11-13

Humphrey P, Harvey C, Visser R

DEPLOYING AN EARLY-STAGE CYBER-PHYSICAL SYSTEM FOR THE IMPLEMENTATION OF FORESTRY 4.0 IN A NEW ZEALAND TIMBER HARVESTING CONTEXT

Abstract: Industry 4.0 is a concept using enabling technologies to increase efficiency for industries that can digitalise production processes. Industry 4.0 is intended to be an interconnected system, shifting from centralised to decentralised production control, with optimisation completed at multiple levels in real time. It facilitates communication between humans and machines with data. Forestry 4.0 is the adaption to the forest industry where high mechanisation rates in forest harvesting operations provide a clear opportunity for digitalisation and optimisation. A Cyber-Physical System (CPS) is an enabling technology that connects the physical and virtual domains. Implementing a CPS across a mechanised harvesting operation presents opportunities such as real-time optimisation of machine tasking or predicting machine maintenance needs. While economic benefits are commonly cited as the main driver for Forestry 4.0, the literature indicates that barriers like technology, costs, education, and organisational structure have hindered progress to date. This paper develops a CPS for harvesting systems. Using a New Zealand-based case study, it demonstrates early-stage implementation where Controller Area Network data was live-streamed from a felling machine, analysed and presented on an interactive online dashboard. This system allows logging contractors to monitor the operations of their machines in real time outside the area of work, while also storing data for future analyses. However, without linking the entirety of the harvesting operations, the economic benefits and realisation of Forestry 4.0 are limited.

Keywords: Forestry 4.0, Cyber-Physical Systems, CANbus, New Zealand, Forest Harvesting, Industry 4.0, J1939

iForest 17 (6): 353-359 (2024) - doi: 10.3832/ifor4651-017
https://iforest.sisef.org/contents/?id=ifor4651-017

Research Articles: Exploring the reliability of CAN-bus data in assessing forwarder rolling resistance under real working conditions

Guerra F, Marzini S, Sforza F, Wagner T, Marinello F, Grigolato S — 2024-11-13

Guerra F, Marzini S, Sforza F, Wagner T, Marinello F, Grigolato S

EXPLORING THE RELIABILITY OF CAN-BUS DATA IN ASSESSING FORWARDER ROLLING RESISTANCE UNDER REAL WORKING CONDITIONS

Abstract: The interaction between off-road vehicles and terrain in forestry operations has been extensively studied to assess machine performance and soil damage, emphasizing the importance of the relationship between machine mobility and terrain conditions. This study assesses the rolling resistance coefficient (μr) using engine data acquired through CAN-bus systems and the J1939 standard. The aim is to determine whether soil-machine interactions can be detected by modeling rolling resistance coefficients with a simple approach based on machine parameters and essential terrain characteristics. The study was conducted on a forwarder (John Deere® 1210G) across different terrain surfaces and load conditions. CAN-bus data were processed, while terrain characteristics and slope were determined using high-accuracy spatial data. The activities consisted of (i) a calibration test to evaluate the model’s sensitivity and (ii) a field test in a real working scenario. The developed methodology demonstrated sufficient sensitivity to detect increasing rolling resistance values on rougher surfaces, highlighting the impact of surface type on forwarder operations. Field tests revealed lower rolling resistance values for the unloaded forwarder (between 0.15 and 0.3) than loaded conditions (from 0.4 to 0.6). The model reliably captured μr changes between consecutive drives and skids, particularly during uphill operations, with significant differences influenced by trail conditions and forwarder interactions rather than just load. By providing a practical methodology for assessing off-road machine performance and its impact on driving surfaces, the study highlights the importance of understanding off-road vehicle dynamics for informed operation planning decisions. This study underscores that integrating real-time mobility data from CAN-bus technology with terrain analysis enhances operational efficiency and helps minimize soil damage, thereby supporting more sustainable forest management practices.

Keywords: Soil, Forest Operations, Rolling Resistance Coefficient, Forwarder, Efficiency, Logging, J1939, CAN-bus

iForest 17 (6): 360-369 (2024) - doi: 10.3832/ifor4687-017
https://iforest.sisef.org/contents/?id=ifor4687-017

Research Articles: Validation of models using near-infrared spectroscopy to estimate basic density and chemical composition of Eucalyptus wood

Mesquita Pimenta E, Dos Santos Brito EG, Ramalho FMG, Hein PRG — 2024-11-03

Mesquita Pimenta E, Dos Santos Brito EG, Ramalho FMG, Hein PRG

VALIDATION OF MODELS USING NEAR-INFRARED SPECTROSCOPY TO ESTIMATE BASIC DENSITY AND CHEMICAL COMPOSITION OF EUCALYPTUS WOOD

Abstract: Determining the wood properties is fundamental because these properties are directly related to wood quality. The near-infrared (NIR) spectroscopy technique has been used to determine various properties of wood. However, even with promising results, NIR spectroscopy needs to be further investigated to evaluate the robustness of its estimates. The objective of this study was to develop regression models from NIR spectra to estimate the basic density and the extractive and lignin contents of wood as well as to verify their robustness through independent and cross-validation. NIR spectra were initially obtained through an integration sphere and optical fiber for the transverse and radial faces of solid wood and through an integration sphere for powdered wood. The wood basic density and the extractive and lignin contents were determined by conventional methods in 180 and 143 specimens, respectively. The samples were collected from Eucalyptus urophylla × Eucalyptus grandis clones aged 5 years. The basic density and extractive and lignin content values were correlated with the NIR spectra by a partial least squares regression. The best models for estimating the basic density of the wood were generated from the spectra obtained on the transverse surface, both with the integration sphere pathway and in the optical fiber pathway. For estimating the chemical properties of wood, the best models were developed from the powdered wood via the integration sphere for assessing the extractive content, Klason lignin, acid-soluble lignin content and total lignin. In all the models, the mathematical treatment of the data by the first derivative was essential for better fitting the models and reducing the error. We concluded that NIR spectroscopy was effective for the estimation of basic density and extractive and lignin contents of wood.

Keywords: Eucalyptus Wood, Near Infrared, Density, Extractive, Lignin

iForest 17 (6): 338-345 (2024) - doi: 10.3832/ifor4516-017
https://iforest.sisef.org/contents/?id=ifor4516-017

Research Articles: Effects of different nut pretreatments and substrates on germination and seedlings growth of Neocarya macrophylla Sabine in Basse Casamance, Senegal

Sambou A, Dieme JS, Camara B, Dione F, Balde B — 2024-11-03

Sambou A, Dieme JS, Camara B, Dione F, Balde B

EFFECTS OF DIFFERENT NUT PRETREATMENTS AND SUBSTRATES ON GERMINATION AND SEEDLINGS GROWTH OF NEOCARYA MACROPHYLLA SABINE IN BASSE CASAMANCE, SENEGAL

Abstract: Neocarya macrophylla Sabine (Gingerbread plum) is a tree species that plays an important role in providing ecosystem services. Despite its importance, the diversity and density of N. macrophylla stands have decreased significantly due to natural and anthropogenic factors. There is a need for better knowledge of N. macrophylla seedling production techniques for successful reforestation. This study aimed to evaluate the effects of pre-treatment and substrates on germination and growth of N. macrophylla seedlings. A completely randomized design with three replications and 12 elementary plots of nine polyethylene bags was installed. The three studied factors were provenances (Enampor and Mlomp), pre-treatments (crushed and non-crushed nuts), and substrates (cow and peanuts manures and control-sand). Nut and kernel size and weight, germination, growth parameters (height, diameter, number of leaves and lateral roots, and length of main root), and dry biomass were measured. The results showed that nut size and weight varied significantly (p<0.0005) among the provenances. Nuts from Enampor were longer (3.41 ± 0.04 cm), wider (2.89 ± 0.03 cm), and heavier (16.15 ± 0.32 g) than those from Mlomp. Pretreatments significantly (p<0.05) influenced germination rate and duration. Crushed nuts had the best rate (43.27 ± 5.19%) and germinated significantly faster (26.23 ± 1.61 days) than non-crushed nuts. Substrate significantly influenced growth parameters and biomass. Peanuts manure promoted a larger growth in height (8.92 ± 0.17 cm), diameter (0.072 ± 0.01 cm), leaf production (10.05 ± 0.18), and biomass (1.80 ± 0.20 g). Leaves (2.03 ± 0.16 g) and roots (2.10 ± 0.16 g) produced more biomass than stems (0.69 ± 0.05 g). The best performance of Neocarya macrophylla seedlings was recorded in peanuts and cow manures.

Keywords: Neocarya macrophylla, Germination, Performance, Provenance, Pretreatment, Substrates

iForest 17 (6): 346-352 (2024) - doi: 10.3832/ifor4528-017
https://iforest.sisef.org/contents/?id=ifor4528-017

Research Articles: Measuring natural sap production in sugar maple at daily temporal resolution

Kurokawa SYS, Bhatt G, De Lima Santos G, Silvestro R, Delagrange S, Rossi S — 2024-10-19

Kurokawa SYS, Bhatt G, De Lima Santos G, Silvestro R, Delagrange S, Rossi S

MEASURING NATURAL SAP PRODUCTION IN SUGAR MAPLE AT DAILY TEMPORAL RESOLUTION

Abstract: Sap yield for maple syrup production is well studied at annual scale. However, the phenological timings of sap production have been less explored. Our study tested the use of rain gauges for monitoring timings and dynamics of sap production at daily temporal resolution. The batteries of the rain gauges were tested under controlled conditions at temperatures ranging from -20 to 5 °C and logging intervals of 15 and 30 minutes. In 2022, eight rain gauges were installed in the field on maples located in four sites along a latitudinal gradient in Quebec, Canada. The batteries performed well at all temperatures in both field and controlled conditions, showing a higher state of charge at logging intervals of 30 minutes with temperatures warmer than -15 °C. The dynamics of sap exudation were correlated among and within sites, demonstrating that trees respond to common environmental factors at regional scale. The natural sap production was discontinuous, alternating productive and non-productive days. Overall, 74% of the sap was exudated during 20% of the sugar season, which matched the proportions described by the Pareto law. Such a heterogeneous and unbalanced distribution in sap exudation exposes small producers to challenges for the use of equipment and makes maple syrup production sensitive to climate hazards in a context of climate change.

Keywords: Acer saccharum Marsh., State of Charge, Rain Gauge, Sap Exudation, Sap Yield, Tipping Bucket

iForest 17 (5): 323-330 (2024) - doi: 10.3832/ifor4591-017
https://iforest.sisef.org/contents/?id=ifor4591-017

Research Articles: Experimental reforestation with Bosnian pine under Mediterranean mountain conditions

Corona P, Bernardini V, Muzzalupo I, Turco R, Garofalo K, Pignatti G — 2024-10-19

Corona P, Bernardini V, Muzzalupo I, Turco R, Garofalo K, Pignatti G

EXPERIMENTAL REFORESTATION WITH BOSNIAN PINE UNDER MEDITERRANEAN MOUNTAIN CONDITIONS

Abstract: The Bosnian pine is a relict species of the Tertiary Oro-Mediterranean forests, with a distribution mainly extended over the Balkan peninsula and disjunct Italian populations on the mountain ranges between the regions of Basilicata and Calabria. The ability to adapt to harsh climatic conditions, to survive in difficult environments and the wide altitudinal range where it is possible to find natural populations are the main reasons this species has been considered in planning reforestation interventions. This study compares growth and survival performances in two experimental plots of Bosnian pine reforestations established on different pedogenic substrates (Mesozoic limestone rocks vs. Paleozoic granites) of the mountains of Calabria using different types of propagation material (bare-root vs. containerized seedlings). At an age of approximately 40 years, annual increments in the two experimental plots averaged over the last two decades were equal to 0.2 cm and 0.1 cm, 0.2 m and 0.3 m, 8.4 m3 ha-1 and 7.3 m3 ha-1 for diameter, height and volume, respectively. These results confirm the ability of the species to successfully cope with the edaphic poverty of the outcropping rocky substrates and the rigidity of the climatic factors that characterize Mediterranean mountains; the growth performances are somewhat unexpected, higher than the average ones registered in Italy for black pine forests. Operationally, the production system of bare-root seedlings does not guarantee the best results under the examined conditions. This study contributes to improving the potential use of the species for new reforestation and related nursery activities, necessary for in-situ and ex-situ conservation.

Keywords: Pinus leucodermis, Forest Restoration, Forest Reproductive Material, Bare-root Seedlings, Containerized Seedlings

iForest 17 (5): 331-337 (2024) - doi: 10.3832/ifor4635-017
https://iforest.sisef.org/contents/?id=ifor4635-017

Review Papers: Forest health under climate change: impact of insect pests

Bracalini M, Balacenoiu F, Panzavolta T — 2024-09-30

Bracalini M, Balacenoiu F, Panzavolta T

FOREST HEALTH UNDER CLIMATE CHANGE: IMPACT OF INSECT PESTS

Abstract: The impact of climate change on forests is difficult to predict, as it depends on multiple factors and the final effect may vary in different parts of our planet. However, these effects can be sorted in “direct”, when they act directly on plants, and “indirect”, when they act through other agents. Among the indirect ones, there are those mediated by biotic factors, particularly insect pests. The impact of climate change on insect pests varies depending on the insect species and the type of forest. Some plant-feeding insects may be disfavoured by climate change, with a consequent reduction in population density and thus in damage to forests. However, many outbreaks of forest insects have been recently recorded as related to climate change. In fact, some insect pests, in certain regions of the world, may benefit from higher temperatures, as it has been demonstrated for some devastating defoliators. In addition, more frequent drought and extreme events may favour other pests, particularly bark beetles and wood-boring insects. Bark beetles are the most dangerous ones because their aggressiveness changes with population density. They can attack only stressed trees at low population densities, while, once the populations have reached high density, they are even able to attack healthy trees in widespread areas.

Keywords: Bark Beetles, Defoliators, Outbreaks, Voltinism

iForest 17 (5): 295-299 (2024) - doi: 10.3832/ifor4520-017
https://iforest.sisef.org/contents/?id=ifor4520-017

Research Articles: Extreme climatic events, biotic interactions and species-specific responses drive tree crown defoliation and mortality in Italian forests

2024-09-30

Bussotti F, Papitto G, Di Martino D, Cocciufa C, Cindolo C, Cenni E, Bettini D, Iacopetti G, Ghelardini L, Moricca S, Panzavolta T, Bracalini M, Pollastrini M

EXTREME CLIMATIC EVENTS, BIOTIC INTERACTIONS AND SPECIES-SPECIFIC RESPONSES DRIVE TREE CROWN DEFOLIATION AND MORTALITY IN ITALIAN FORESTS

Abstract: The frequency of forest disturbances has increased in recent years, provoking widespread defoliation, crown dieback and tree mortality. The ICP Forests monitoring network offers a unique platform for observing the impacts on forests of heatwaves, droughts and other extreme climatic events, as well as the trends of defoliation and mortality. The Italian ICP Forests Level I network consists of 261 permanent plots where tree crown defoliation and damage symptoms are assessed visually each year by well-trained crews of the Corpo Forestale dello Stato (2001-2016) and the Carabinieri Forestale from 2017 onward. This paper aims to assess the main tree species’ responses, in terms of defoliation and mortality, to severe climatic events. The results are discussed in relation to species-specific physiological behaviour and bioclimatic regions. A significant trend toward increasing defoliation and mortality has been observed since 2010 in both conifers and broadleaves. Conifers (especially Picea abies), which are largely diffuse in the Alpine regions, have suffered from bark beetle outbreaks due to severe windstorms (such as Vaia in 2018) and recurrent dry years. In the temperate regions, characterised by deciduous broadleaved trees, the most relevant defoliation events coincided with the driest and hottest years, with low relative humidity (2012, 2017 and 2021-2022), only partially recovering in the subsequent years. Among them, Fagus sylvatica and Quercus cerris, along with increased defoliation, showed symptoms caused by fungi of the genus Biscogniauxia, causal agents of “charcoal canker”, in less favourable site conditions. Quercus pubescens was the most resilient species, able to restore its crown after defoliation. The Mediterranean forests, with evergreen broadleaved species, showed no significant trends but were impacted at the most drought-prone coastal sites. The findings evidenced that the current ICP Forests network in Italy represents a fundamental infrastructure for monitoring impacts and trends connected to climate change and species-specific responses. A local intensification of the grid would help to capture under-represented species or ecological conditions.

Keywords: Climate Change, Crown Defoliation, Emerging Forest Diseases, Forest Health Monitoring, Heatwaves and Droughts, ICP Forests, Tree Ecophysiology, Tree Mortality

iForest 17 (5): 300-308 (2024) - doi: 10.3832/ifor4531-017
https://iforest.sisef.org/contents/?id=ifor4531-017

Review Papers: Linking patterns of forest dieback to triggering climatic and weather events: an overview on Mediterranean forests

Alderotti F, Bussotti F, Brunetti C, Ferrini F, Gori A, Pollastrini M — 2024-09-30

Alderotti F, Bussotti F, Brunetti C, Ferrini F, Gori A, Pollastrini M

LINKING PATTERNS OF FOREST DIEBACK TO TRIGGERING CLIMATIC AND WEATHER EVENTS: AN OVERVIEW ON MEDITERRANEAN FORESTS

Abstract: Mediterranean forest ecosystems are highly vulnerable to climate extremes and anomalies induced by climate change, as evidenced by the increase in forest tree decline and death over the past few decades. Forest dieback may occur with different spatial patterns and in response to many climatic and weather events (i.e., drought spells, heat waves, compound events or hot drought, cold spells, and windstorms). This paper describes the physiological behaviour of Mediterranean tree species (namely evergreen sclerophyllous trees) under extreme climatic events, with a focus on embolism formation and carbon depletion. Additionally, we describe three widely recognised patterns of forest dieback: die-off, patchy dieback, and salt and pepper dieback. Overall, drought spells, heat waves, and compound events have been reported to induce all the mortality patterns described, revealing the great vulnerability of Mediterranean forests to rising air temperature and vapour pressure deficit trends. Many intrinsic factors of plant and structural and contingent factors of the forest can interact, favouring one mortality pattern over another. Patterns of dieback and mortality are the product of the interaction between the complexity of the landscape, the species assemblage, the kind and intensity of the disturbance, and biotic factors. Different patterns have different ecological consequences, and implications for monitoring and management. The combination of terrestrial and remote sensing (RS) is recommended.

Keywords: Mediterranean Forest, Forest Mortality, Climate Change, Drought-induced Dieback

iForest 17 (5): 309-316 (2024) - doi: 10.3832/ifor4545-017
https://iforest.sisef.org/contents/?id=ifor4545-017

Review Papers: SilvaCuore: a web-application to monitor the health status of Italian forests

Castellaneta M, Colangelo M, Colle G, Rita A, Ripullone F — 2024-09-30

Castellaneta M, Colangelo M, Colle G, Rita A, Ripullone F

SILVACUORE: A WEB-APPLICATION TO MONITOR THE HEALTH STATUS OF ITALIAN FORESTS

Abstract: In the current context of climate change, this paper provides a brief overview of climate-vegetation interactions in the Mediterranean basin, where global warming and aridification trends are predicted to intensify. Rising temperatures coupled with extreme drought events have notable impacts on forest ecosystems, triggering dieback and mortality phenomena worldwide. The health status of forest vegetation may be assessed by either ground surveys or remote sensing. Several investigations of declining oak forests in the Apennine region have shown that the drought vulnerability of Mediterranean oaks is dependent on differences in access to deep soil water pools, which can be related to differences in rooting depth, tree size and growth rate. Forest dieback is widely reported in Italy, but the extent and overall distribution of this phenomenon have not yet been well defined. Thus, understanding the future dynamics of forest stands has several key objectives: inventorying declining forest stands to gain insight into the phenomenon and create a national-level database; locating these stands to allow monitoring of their evolution over time; and monitoring to allow planning of mitigation measures, as well as recovery and adaptation strategies. This background led to the implementation of SilvaCuore, the first web application designed in Italy to report forest health status. Silvacuore is a web application developed with the aim of improving the link between citizens and the scientific community by contributing to the development of a valuable scientific database. The direct involvement of citizens in forest preservation offers an interesting perspective because the innovative use of technology can tap into citizens’ growing enthusiasm for environmental topics. Thus, SilvaCuore may be viewed from a dual perspective as a resource for the scientific community and as a unique opportunity for citizens to take an active role in research activities (Citizen Science project).

Keywords: Climate Change, Citizen Science, Drought, Forest Dieback, Mediterranean Environment

iForest 17 (5): 317-322 (2024) - doi: 10.3832/ifor4562-017
https://iforest.sisef.org/contents/?id=ifor4562-017

Research Articles: Modeling aboveground carbon in flooded forests using synthetic aperture radar data: a case study from a natural reserve in Turkish Thrace

Vatandaslar C, Bolat F, Abdikan S, Pamukcu-Albers P, Satiral C — 2024-09-27

Vatandaslar C, Bolat F, Abdikan S, Pamukcu-Albers P, Satiral C

MODELING ABOVEGROUND CARBON IN FLOODED FORESTS USING SYNTHETIC APERTURE RADAR DATA: A CASE STUDY FROM A NATURAL RESERVE IN TURKISH THRACE

Abstract: Flooded forests are rare and highly dynamic ecosystems, yet they can store a significant amount of carbon because of their ability to produce biomass rapidly. Estimation and mapping of the carbon that is stored in flooded forests are challenging tasks through the use of optical remote sensing because these ecosystems are often located in moist regions where clouds can interfere with data acquisition and image interpretation. This study models the aboveground carbon (AGC) stocks of a flooded forest in Turkish Thrace with synthetic aperture radar (SAR) data, which are less affected by weather and illumination conditions compared to optical imagery. Forest management plan data, including inventory records of 229 sample plots, a detailed forest cover map, and stand tables of the 2.119-ha Igneada Longoz Forest, were used to calculate AGC and to develop spatially explicit models based on ALOS/PALSAR-2 (Advanced Land Observing Satellite/Phased Array L-band Synthetic Aperture Radar) and Landsat-8 images. The results indicated that the horizontally transmitted and horizontally received (HH) and cross-polarization ratio (CPR) bands of ALOS/PALSAR were the most influential variables in the linear and nonlinear regression models. The models did not include any variables from either radar- or optical-based vegetation indices. While the estimation accuracies of the two models were similar (root mean square percentage error ≈ 26%), the linear model yielded negative estimations in several land cover classes (e.g., dune, forest opening, degraded forest). AGC stock was estimated and mapped using the nonlinear model in these cases. The density map revealed that Igneada Longoz Forest stored 279,258.9 t AGC, with a mean and standard deviation of 124 ± 115.4 t C ha-1. AGC density varied significantly depending on stand types and management units across the forest, and carbon hotspots accumulated in the northern and southern sites of the study area, primarily composed of ash and alder seed stands. The models and maps that this study developed are expected to help in the rapid and cost-effective assessment of AGC stored in flooded forest ecosystems across the temperate climate zone.

Keywords: SAR Mosaics, Landsat-8, Normalized Difference Vegetation Index (NDVI), Aboveground Biomass and Carbon Stocks, Carbon Density Maps, Bottomland Forests, National Parks, Igneada

iForest 17 (5): 277-285 (2024) - doi: 10.3832/ifor4527-017
https://iforest.sisef.org/contents/?id=ifor4527-017

Research Articles: No home-field advantage in upper Andean tropical forests despite strong differences in site environmental characteristics

Castillo-Figueroa D — 2024-09-27

Castillo-Figueroa D

NO HOME-FIELD ADVANTAGE IN UPPER ANDEAN TROPICAL FORESTS DESPITE STRONG DIFFERENCES IN SITE ENVIRONMENTAL CHARACTERISTICS

Abstract: Litter decomposition is not fully explained by the general triangle of climate, litter quality and soil decomposers. Therefore, other theoretical frameworks, such as Home-Field Advantage (HFA), have emerged to explain the remaining variation of decomposition. HFA states that litter decomposes faster in their site of origin (home) than far from it (away). However, there are no consistent patterns of HFA and this can varies depending the ecosystem and plant species analyzed. One of the most variable ecosystems in terms of species biodiversity turnover, topography, and soil conditions are the Upper Andean Tropical Forests (UATF), but to date there is no study testing HFA in this ecosystem. Here, HFA was tested through a reciprocal litterbag translocation field experiment across different UATF. The experiment comprised 2520 litterbags placed in 14 20 × 20 m plots that belonged to four sites to analyze decomposition of 15 plant species for 18 months. Of these 15 species, seven were present at only one site. The mean decomposition was calculated for all 15 species to determine the relative decomposition at each site and the decomposition of the seven species at home and away sites was analyzed through two-way ANOVA (sites × species) and linear mixed models. I contrasted environmental charcteristics between sites including litter depth, slope, leaf area index, canopy openness, and microclimatic variables. The results showed that the pattern of decomposition was always the same, no matter the origin of the species and the decomposition period. Microclimate, litter depth, and slope varied between sites, yet these differences were not enough to influence affinity effects of decomposition, as relative decay rates were similar between home and away sites. Overall, no HFA was found in UATF possibly because: (i) strong environmental filters along montane forests homogenize decomposer communities; (ii) high diversity in litters drive decomposers with high ability to degrade different organic compounds; (iii) little adaptation of decomposers to recurrent litter as they respond mainly to changes in litter quality. These results imply that changes in species composition by current anthropogenic pressures could have profound impacts on carbon cycle and nutrient fluxes depending on the identity of species arriving in UATF.

Keywords: Carbon Cycling, Colombian Andes, Litter Decomposition, Litter Affinity Effects, Montane Forests, Nutrient Cycles, Reciprocal Litter Transplant, Plant-soil Feedbacks

iForest 17 (5): 286-294 (2024) - doi: 10.3832/ifor4518-017
https://iforest.sisef.org/contents/?id=ifor4518-017

Research Articles: Optimizing line-plot size for personal laser scanning: modeling distance-dependent tree detection probability along transects

Ritter T, Tockner A, Krassnitzer R, Witzmann S, Gollob C, Nothdurft A — 2024-09-07

Ritter T, Tockner A, Krassnitzer R, Witzmann S, Gollob C, Nothdurft A

OPTIMIZING LINE-PLOT SIZE FOR PERSONAL LASER SCANNING: MODELING DISTANCE-DEPENDENT TREE DETECTION PROBABILITY ALONG TRANSECTS

Abstract: Personal laser scanning (PLS) systems are gaining popularity in forest inventory research and practice. They are primarily utilized on circular or compact rectangular sample plots to mitigate potential instrument drift and enhance tree detection rates, and a closed-loop scan path is usually implemented to achieve these objectives, ensuring thorough coverage of the plot. This study introduced a novel approach by applying the distance-sampling framework to PLS data collected during walks along line transects. Modeling the distance-dependent probability of tree detection using PLS coupled with automatic routines for point cloud processing aimed to ascertain the optimal width of line-plots to maximize tree detection rates. The optimized plots exhibited tree detection rates exceeding 99%, which facilitated accurate estimates of tree density, basal area, and growing stock volumes. This proposed method demonstrated considerable potential for data collection while walking along line transects in forests. For instance, the otherwise unproductive working time of field crews moving between systematically arranged sample plots can be utilized for additional data collection without generating additional costs. This innovative approach not only enhances operational efficiency but also establishes a foundation for further advancements to explore PLS applications in forest management practices.

Keywords: Personal Laser Scanning, Lidar, Forest Inventory, Distance Sampling, Line Transect Sampling, Tree Detection

iForest 17 (5): 269-276 (2024) - doi: 10.3832/ifor4588-017
https://iforest.sisef.org/contents/?id=ifor4588-017

Research Articles: Seedling emergence capacity and morphological traits are under strong genetic control in the resin tree Pinus oocarpa

Velasco-García Mario V, Muñoz-Gutiérrez L, Martínez-Cantera G — 2024-08-16

Velasco-García Mario V, Muñoz-Gutiérrez L, Martínez-Cantera G

SEEDLING EMERGENCE CAPACITY AND MORPHOLOGICAL TRAITS ARE UNDER STRONG GENETIC CONTROL IN THE RESIN TREE PINUS OOCARPA

Abstract: Pinus oocarpa is a widely distributed species essential for resin production in Mexico, where demand surpasses supply. This study aimed to identify differences and variation levels of seedling emergence capacity and morphological traits in resin-producing high-yield P. oocarpa trees and estimate their genetic control. Seeds from 72 open-pollinated families were planted using a randomized complete block experimental design. Differences between families were determined and pooled using cluster analysis. We recorded wide differences in seed emergence capacity and morphological traits (cotyledon number and length, and hypocotyl length), allowing to establish three family groups. We also calculated the contribution of the variation sources to the total variance and genetic parameters involved. Our data evidenced high genetic control for all tested variables. We found a moderate and positive genetic correlation between cotyledon length, cotyledon number, and hypocotyl length. We also found a high negative genetic correlation between emergence capacity and hypocotyl length. At the phenotypic level, we found a high and significant correlation between cotyledon length and number. Grouping P. oocarpa into families should aid decision-making for sexual propagation since a high propagation capacity of the high-yield trees is essential for genetic improvement programs. Moreover, we demonstrate that the heritability of the emergence capacity and other morphological traits is high; these traits can be useful for the early selection of high-yield families.

Keywords: Egg-cone pine, Cotyledons, Genetic Control, Genetic Correlation, Genetic Variation, Heritability

iForest 17 (4): 245-251 (2024) - doi: 10.3832/ifor4397-017
https://iforest.sisef.org/contents/?id=ifor4397-017

Review Papers: The soil-conscious forestry and the forbidden apple

Zanella A, Bernier N, Zampedri R, Fusaro S, Mei G, André J, Ponge JF, Giannini R — 2024-08-16

Zanella A, Bernier N, Zampedri R, Fusaro S, Mei G, André J, Ponge JF, Giannini R

THE SOIL-CONSCIOUS FORESTRY AND THE FORBIDDEN APPLE

Abstract: In this article, we propose a silvicultural approach that takes soil health into account. Using a biblical metaphor, the first chapter highlights the forest’s critical role in the planet’s future, emphasizing that forest biodiversity is essential for sustaining a planet inhabited by complex life forms like humans. The second chapter focuses to the soil, explaining how the biological dynamics of the soil are interconnected with the forest cycle, demonstrating that vegetation and soil form a continuous, co-evolving system. The third chapter explores the possibility of extending the forest cycle to restore soil functionality, illustrating how the recycling of the forest’s biological past facilitates the emergence of a new, evolving soil-vegetation system. Examples of forest management practices in France, Italy, and Switzerland are presented, including graphs and mathematical models depicting the evolution of organic carbon in the soil and the distribution of tree stems by diameter, age, and stature. The description of uneven-aged Swiss forests, featuring fir and beech, is sourced from the Helvetica Pro-Silva website.

Keywords: Anthropocene, Adam and Eve, Forest Soil, Humus, Soil-conscious Forestry, Envers Forest, Forest Dynamic, Old-growth Forest

iForest 17 (4): 252-268 (2024) - doi: 10.3832/ifor4584-017
https://iforest.sisef.org/contents/?id=ifor4584-017

Research Articles: Chitosan exhibits variable effects on pine (Pinus sylvestris L.) and alder (Alnus glutinosa L.) growth and secondary metabolism

Šilanskiene M, Sirgedaite-Šežiene V, Vaitiekunaite D, MKDS Co — 2024-08-06

Šilanskiene M, Sirgedaite-Šežiene V, Vaitiekunaite D, MKDS Co

CHITOSAN EXHIBITS VARIABLE EFFECTS ON PINE (PINUS SYLVESTRIS L.) AND ALDER (ALNUS GLUTINOSA L.) GROWTH AND SECONDARY METABOLISM

Abstract: Chitosan is a naturally abundant biopolymer that has been studied as an alternative means to elicit beneficial responses in plants, such as enhanced plant growth and improved defense response. Most studies focus on agriculture and horticulture, but few have investigated forest trees. Based on chitosan’s success as a biostimulant, we hypothesized that trees such as pine (Pinus sylvestris L.) and alder (Alnus glutinosa L.) may also be positively affected by it. We evaluated vegetative growth parameters and secondary metabolites (phenolics, antioxidant indicators), pigments of seedlings grown in sterile in vitro and non-sterile ex vitro conditions to determine if various concentrations of chitosan solubilized in different solvents and stored in different conditions would significantly impact trees at various stages and conditions of growth. Results showed that in in vitro conditions, chitosan had a mainly positive effect on pine germination and growth, but a mainly negative effect on pine secondary metabolism (SM) indicators. In vitro grown alder’s SMs were positively affected in all measured parameters, but chitosan had no effect on growth. Overall, ex vitro results indicated that chitosan has no effect on pine growth and varied impact on its SM indicators. Similarly, the effect on growth parameters and SM indicators was varied in alder. Results on how chitosan storage can affect its impact on tree growth showed that storage conditions had a significant impact on both pine and alder. Based on our data, future studies must carefully evaluate all possible variables to optimize chitosan use in silviculture.

Keywords: Forest, Tree, Chitosan, Growth Improvement, Secondary Metabolites

iForest 17 (4): 236-244 (2024) - doi: 10.3832/ifor4404-017
https://iforest.sisef.org/contents/?id=ifor4404-017

Research Articles: Automated irrigation management system for tree species seedlings using weighing mini-lysimeters

2024-08-03

Fonseca de Carvalho D, Rodrigues da Costa G, Faria Conforto BAA, Ferreira Pinto M, Ribeiro da Silva M

AUTOMATED IRRIGATION MANAGEMENT SYSTEM FOR TREE SPECIES SEEDLINGS USING WEIGHING MINI-LYSIMETERS

Abstract: Due to the lack of irrigation management techniques, the application of water in forest nurseries is generally carried out without control, resulting in great waste. This study aimed to develop and evaluate weighing mini-lysimeters (ML) to automate the irrigation system and determine the water demand and evaluation of the initial tree species seedling growth. The structure was built out of wood to fit a tray of 54 tubes measuring 280 cm³. It was equipped with a load cell with a nominal capacity of 10 kg, located in the center of the structure. The mass variations of the set were recorded on a micro SD card using an Arduino Mega board, which allowed for the automated irrigation management system through an algorithm. Two MLs were built, determining the water demand of Dalbergia nigra (DN) and Enterolobium contortisiliquum (EC) seedlings in the initial growth phase. After calibration, the MLs presented an absolute error and mean squared error below 1% of the total mass, allowing effective irrigation control. During the evaluation period, 1.47 L seedling-1 of DN and 1.45 L seedling-1 of EC were applied, reaching 89 days after emergence, height and stem diameter of 39.2 cm and 3.4 mm, and 19.3 cm and 4.6 mm, respectively. The weighing mini-lysimeters developed demonstrated the ability to automate the irrigation of tree species seedlings, reducing the amount of water applied in forest nurseries.

Keywords: Evapotranspiration, Nursery, Mini-lysimeters, Dalbergia nigra, Brazilian rosewood, Enterolobium contortisiliquum, Pacara earpod tree

iForest 17 (4): 222-228 (2024) - doi: 10.3832/ifor4409-017
https://iforest.sisef.org/contents/?id=ifor4409-017

Research Articles: Identification and characterization of gaps and roads in the Amazon rainforest with LiDAR data

Spiazzi Favarin JA, Sabadi Schuh M, Marchesan J, Alba E, Soares Pereira R — 2024-08-03

Spiazzi Favarin JA, Sabadi Schuh M, Marchesan J, Alba E, Soares Pereira R

IDENTIFICATION AND CHARACTERIZATION OF GAPS AND ROADS IN THE AMAZON RAINFOREST WITH LIDAR DATA

Abstract: Gap formations in the forest canopy have natural causes, such as bad weather, and anthropic ones, such as sustainable selective extraction of trees and illegal logging, which can already be detected through orbital remote sensing. However, the Amazon region is under frequent cloud cover, which makes it challenging to detect gaps using passive sensors. This study aimed to identify and delimit gaps in the Amazon forest canopy through airborne LiDAR (Light Detection and Ranging) sensor application while testing six different return densities. LiDAR and forest inventory data were obtained over an Amazon rainforest region, defining the minimum area as a forest canopy gap. The point cloud was processed to obtain six return densities with the generation of their respective CHM (Canopy Height Model), which were applied for segmentation and subsequent identification of gap areas and roads. The minimum gap area found was 34 m2, and the Kruskal Wallis test showed no significant difference among the six densities in gap detection; however, road identification decreased as the return density decreased. We concluded that LiDAR data proved promising as point clouds with low return density can be used without impairing gap identification. However, reducing the return density for road identification is not recommended.

Keywords: Forest Canopy Gaps, Aerial Laser Scanning, Point Density, Remote Sensing

iForest 17 (4): 229-235 (2024) - doi: 10.3832/ifor4295-017
https://iforest.sisef.org/contents/?id=ifor4295-017

Research Articles: Comparative analysis of taper models for Pinus nigra Arn. using terrestrial laser scanner acquired data

Boukhris I, Puletti N, Vonderach C, Guasti M, Lahssini S, Santini M, Valentini R — 2024-07-22

Boukhris I, Puletti N, Vonderach C, Guasti M, Lahssini S, Santini M, Valentini R

COMPARATIVE ANALYSIS OF TAPER MODELS FOR PINUS NIGRA ARN. USING TERRESTRIAL LASER SCANNER ACQUIRED DATA

Abstract: Taper equations are indispensable tools for characterizing the stem profile of trees, providing valuable insights for forest management, timber inventory, and optimal assortments allocation. The recent progress in Terrestrial Laser Scanning (TLS) has revolutionized forest inventory practices by enabling non-destructive data collection. In this study, four taper models from three different model categories were established based on point cloud data of 219 Pinus nigra trees. The taper equations fitted with TLS data were used to predict the diameter at specific stem heights and the total stem volume. The results show that among fitted models, the Max and Burkhart segmented model calibrated by the means of a mixed-effects approach provided the best estimate of the diameter at different heights and the total stem volume evaluated for different diameter at breast height (DBH) classes. In numerical terms, this model estimated the diameter and the volume with a respective overall error of 0.781 cm and 0.021 m3. The predicted profile also shows that above a relative height of 0.7, the diameter error tends to increase due to the low reliability of data collected beyond the base of the crown primarily caused by interference from branches and leaves. Nevertheless, this study shows that TLS technology presents a compelling opportunity and a promising non-destructive alternative for generating taper profiles and estimating tree volume.

Keywords: Taper Equations, Volume Equations, Forest Mensuration, Forest Assessment, Environmental Management, Max and Burkhart, B-Splines, Random Forest, TLS

iForest 17 (4): 203-212 (2024) - doi: 10.3832/ifor4525-017
https://iforest.sisef.org/contents/?id=ifor4525-017

Review Papers: An overview of tree ecology and forest studies in the Northern Western Ghats of India

Shigwan BK, Kulkarni A, Smrithy V, Datar MN — 2024-07-22

Shigwan BK, Kulkarni A, Smrithy V, Datar MN

AN OVERVIEW OF TREE ECOLOGY AND FOREST STUDIES IN THE NORTHERN WESTERN GHATS OF INDIA

Abstract: The forests of the Western Ghats (WG) of India are a highly diverse ecosystem though altered over time by human interference. The Northern Western Ghats (NWG) differ in bioclimatic and geological characteristics from the rest of the Western Ghats, featuring a mix of forested and open landscapes. Human activities such as shifting cultivation, cutting, lopping, periodic fire, constructions (road and dam), and mining have further increased their fragmentation, leading to a decrease in biodiversity. While the region has been extensively investigated for its floristic diversity, quantitative ecological studies are limited. This review seeks to identify research gaps and new research directions in the forest ecology of the NWG by compiling various periodical studies carried out in the region. It covers various works on vegetation types, species diversity and composition, and forest degradation due to anthropogenic activities. We provide compiled comparative vegetation types applicable to the region. The present review also discusses works carried out on forest areas under various protection regimes, such as legally protected areas, sacred groves, and private forests, using quantitative and remote sensing tools. We believe that understanding the NWG as an entire unit using uniform methods is essential, and this review serves as an important step in achieving this. It provides a comprehensive overview of the NWG, which can be used to plan out future research in this region.

Keywords: Fragmentation, Disturbance, Remote Sensing, Sacred Groves, Protected Areas

iForest 17 (4): 213-221 (2024) - doi: 10.3832/ifor4471-017
https://iforest.sisef.org/contents/?id=ifor4471-017

Research Articles: Forest therapy in Italy: proposal of a standard procedure for validation of suitable sites

Rivieccio R, Romano R, Orsini S — 2024-07-04

Rivieccio R, Romano R, Orsini S

FOREST THERAPY IN ITALY: PROPOSAL OF A STANDARD PROCEDURE FOR VALIDATION OF SUITABLE SITES

Abstract: The social and health benefits that green areas and forests can provide are now recognized in the scientific community worldwide. There is a growing interest in and demand for forest care initiatives and nature-based therapy, also as a result of the impacts of Covid-19 pandemic. In Italy, the increasing interest in alternative and integrated solutions for care and healthcare promotion have laid the basis for the implementation of several projects and activities, particularly those known as Forest Therapy (FT). These initiatives provide a business opportunity for forestry and social sectors, for the development of rural areas, and they are a cost-saving opportunity for the National Health System because of the expected benefits (as assessed by several clinical studies confirming the therapeutic effectiveness of these activities). Despite the importance, in Italy there is not a specific legal basis and standardized procedures to determine the suitability of a FT site. As a result, FT initiatives have been carried out in different environments, whether in urban or extra-urban forest areas, with the implementation of activities deemed suitable in a “self-referential” approach. Establishing a standard procedure for the recognition of FT suitable locations and related FT activities is a first step for the promotion of an important instrument that can meet several social needs. This work proposes (i) a standard procedure (“iter”) for the validation of a Forest Therapy and Urban forest therapy (UFT) site by the competent authority to obtain the official "environmental recognition" of site suitability; (ii) the technical and objective criteria to assess the stationary and environmental parameters of a site in order to be qualified as a FT/UFT site, both in natural and urban contexts. The iter and criteria proposed take into account the relevant national regulations, the literature found on the subject, and the expertise of scientists and technicians. The procedure and criteria proposed can be used as basis of a regulation on FT in Italy, ensuring suitable sites officially recognised by public institutions and providing a high-quality service to society. Finally, a baseline regulation would also facilitate opportunities for dedicated funding, as well as the recognition of “green prescriptions” for the prevention and treatment of certain health problems.

Keywords: Forest, Forest Therapy, Urban Forest Therapy, Site Suitability, Validation Process

iForest 17 (4): 192-202 (2024) - doi: 10.3832/ifor4543-017
https://iforest.sisef.org/contents/?id=ifor4543-017

Research Articles: Quantitative assessment of past and future tropical forest transition and its dynamic to streamflow of the catchment, Malaysia

Ebrahimian M, Nurruddin AA — 2024-06-30

Ebrahimian M, Nurruddin AA

QUANTITATIVE ASSESSMENT OF PAST AND FUTURE TROPICAL FOREST TRANSITION AND ITS DYNAMIC TO STREAMFLOW OF THE CATCHMENT, MALAYSIA

Abstract: The consequences of human interventions on land use have been empirically demonstrated to affect substantially hydrological processes and ecosystem services within watershed environments. Since 1970, Malaysia has faced deforestation, driven mainly by logging and agricultural expansion, aligning with its developmental goals by 2020. From 1970 to 2000, deforestation led to a 25.5% decline in forested land, causing a significant 10.2% rise in excess runoff. Moreover from 2001 to 2021, the nation lost 17% of its total land to deforestation. These trends emphasize the need for a thorough investigation of sustainable conservation efforts in Malaysia. This study focuses on the Langat basin in Malaysia, evaluating past and future land use changes and their effects on the basin’s hydrological response. The study employed key informant reports, population growth data, observed land use change, field survey and agricultural land availability considered for developing change scenarios. We emphasized the significance of integrating diverse modeling methods to analyze LULC changes effectively. The use of a semi-distributed hydrological model, SWAT, in combination with Markov chain and Multi-Layer Perceptron (MLP) model and Geographic Information Systems (GIS) techniques proved to be an integrated and suitable tool for comprehensive change analysis and modeling of land use. Markov chain modeling is valuable for predicting land use changes over time, providing input scenarios for SWAT simulations. MLP is a powerful algorithm to capture non-linear relationships and complex patterns in the data, enhancing the modeling accuracy. The simulation results, based on historic land use data (1984-2006-2010) and projected future land use maps (2030-2050-2080), revealed a consistent pattern of urban expansion and deforestation leading to increased streamflow. Projections indicated a substantial rise in streamflow by 20%, 61%, and 71% for the 2030s, 2050s, and 2080s, respectively. To mitigate potential flood and sediment loss, it is crucial to involve local stakeholders such as local communities, government bodies, environmental organizations, and businesses. Such analysis facilitates understanding their perspectives and concerns regarding afforestation and urban expansion control, informing future development programs and land use planning effectively.

Keywords: Land Use Conversion, Hydrological Processes, Land Use Scenarios, Markov Chain, SWAT

iForest 17 (3): 181-191 (2024) - doi: 10.3832/ifor4339-017
https://iforest.sisef.org/contents/?id=ifor4339-017

Research Articles: Three prescribed fire regimes on the restoration of flooded savannah grasslands under encroachment of Vochysia divergens Pohl, Pantanal, Brazil

Ebert A, Berlinck CN, Nunes da Cunha C — 2024-06-17

Ebert A, Berlinck CN, Nunes da Cunha C

THREE PRESCRIBED FIRE REGIMES ON THE RESTORATION OF FLOODED SAVANNAH GRASSLANDS UNDER ENCROACHMENT OF VOCHYSIA DIVERGENS POHL, PANTANAL, BRAZIL

Abstract: The proliferation of woody plant species over grassland areas has been reported in different regions of the planet. This phenomenon has caused economic, social and environmental effects in the Brazilian Pantanal. Traditional knowledge based on scientific evidences technically supports the forms of management to control the process of colonization of woody plants in native grasslands, thus promoting the original ecological restoration of these ecosystems. Our study aimed to evaluate three management regimes with prescribed fire for controlling the invasion of Vochysia divergens Pohl. on grassland matrix areas in the Brazilian Pantanal. The results obtained showed that prescribed fire is an efficient tool in controlling V. divergens in the early stages of its establishment, and effectively contributes to ecological restoration processes in the savannah grasslands, aimed at controlling woody tree and shrub species invasions in the grasslands of the Brazilian Pantanal.

Keywords: Ecological Restoration, Wood-plant Encroachment, Prescribed Fire, Wetland, Natural Grassland

iForest 17 (3): 165-171 (2024) - doi: 10.3832/ifor4483-017
https://iforest.sisef.org/contents/?id=ifor4483-017

Research Articles: Estimation of above-ground biomass using machine learning approaches with InSAR and LiDAR data in tropical peat swamp forest of Brunei Darussalam

Zadbagher E, Marangoz AM, Becek K — 2024-06-17

Zadbagher E, Marangoz AM, Becek K

ESTIMATION OF ABOVE-GROUND BIOMASS USING MACHINE LEARNING APPROACHES WITH INSAR AND LIDAR DATA IN TROPICAL PEAT SWAMP FOREST OF BRUNEI DARUSSALAM

Abstract: Forest above-ground biomass (AGB) is one of the critical measures of forest resources. Therefore, it is crucial to identify a reliable method to estimate the AGB, especially in the tropics, where forest ecosystems are exposed to several depleting factors, including deforestation, climate change and replacing natural forests with palm oil tree plantations. We investigated the digital elevation data over the forest and uses an artificial intelligence-based approach to develop a method for quick and cost-effective assessment of the AGB. The study was conducted in the tropical peatland rainforest of Brunei Darussalam. The Shuttle Radar Topography Mission (SRTM) elevation data product and Light Detection and Ranging (LiDAR) digital elevation data were used. A linear regression (LR) model and three different machine learning (ML) algorithms, i.e., Random Forest (RF), Artificial Neural Network (ANN) and Support Vector Machines (SVM), were tested and compared. As model inputs, the SRTM elevation and distance from the peat dome’s center, a feature of a peatland swamp forest, were used. ML methods were trained on the samples taken from the LiDAR elevations. The validation results showed that the SVM was the best method to predict AGB in the study area with R2 = 0.70, RMSE = 83.65 Mg ha-1, and MAE = 74.43 Mg ha-1, which in relative terms corresponds to approximately 6% of the AGB of the forest of interests. This study demonstrated the potential of ML algorithms in AGB estimation based on canopy height derived from the InSAR-based DEM in tropical forests.

Keywords: Above-Ground Biomass, Machine Learning, Tropical Forest, InSAR, Badas Peatland Forest

iForest 17 (3): 172-179 (2024) - doi: 10.3832/ifor4434-017
https://iforest.sisef.org/contents/?id=ifor4434-017

Research Articles: Revealing the physiological basis of forester’s choice of poplar clones (Populus spp.)

Bonnin SM, Alvarez JA, Faustino LI, Graciano C — 2024-06-14

Bonnin SM, Alvarez JA, Faustino LI, Graciano C

REVEALING THE PHYSIOLOGICAL BASIS OF FORESTER’S CHOICE OF POPLAR CLONES (POPULUS SPP.)

Abstract: Poplar plantations cover 31.4 million ha around the world and supply timber for paper, sawn wood and other wood-based products. In each region where poplars are planted, it is possible to identify “model clones” which are massively adopted by foresters. Improving the rationale of clone selection in breeding programs requires a comprehensive understanding of the physiological traits that explain the differences in genotypes growth. Moreover, given that growth is related to the use of resources (water, light and nutrients) we also need to determine which morphological and physiological traits explain the model condition of most widespread clones. A controlled-condition study was carried out to evaluate eight Populus deltoides and two Populus × canadensis clones, including the model Populus deltoides €˜Australiano 129/60’. For each clone, physiological and morphological traits related to biomass partitioning (roots, stem and leaf dry mass), growth (height, diameter), light use (leaf area duration, leaf size, net photosynthetic rate), water use (stem hydraulic conductivity, water consumption) and nutrient use (nitrogen and phosphorus concentrations) were measured. High variability in the physiology and morphology was observed among clones, and similar and contrasting clones in relation to the model clone were identified. Similarities among clones varied depending on the characteristic being evaluated at the time-water use, light use or nutrient use. The results showed that variability not only relates to visible phenotype, but also to functionality. This information is significant since the breeding programs can evaluate non-traditional traits and select genotypes which are similar or complementary to the model clone. The characterization of model clones is key for breeding programs which seek new candidates taking into account the use of water, nutrients and light. It is also important because it helps explain why foresters prefer one clone over others. Knowledge about functional variability within clones of the same species enables foresters to conduct more intelligent and site-specific silviculture and to optimize the genotype selection in breeding programs.

Keywords: Salicaceae, Physiology, Functional Traits, Model Clones, Breeding Program

iForest 17 (3): 156-164 (2024) - doi: 10.3832/ifor4433-017
https://iforest.sisef.org/contents/?id=ifor4433-017

Research Articles: Contrasting resin-tapped and untapped Pinus pinaster Ait. trees of central Spain in a dendroclimatic research

Génova M, Caminero L, Gutiérrez E — 2024-05-30

Génova M, Caminero L, Gutiérrez E

CONTRASTING RESIN-TAPPED AND UNTAPPED PINUS PINASTER AIT. TREES OF CENTRAL SPAIN IN A DENDROCLIMATIC RESEARCH

Abstract: We investigated whether there are significant differences in the climatic response of resin-tapped and untapped maritime pine (Pinus pinaster Ait.) trees in four forest stands in the central mountains of Spain, where the species is of natural origin. The stands are located in different provenance regions, with the westernmost site located on the northern slopes of Sierra de Gredos and the easternmost in the transition to the middle Duero basin, with altitudes ranging from 900 to 1350 m a.s.l. Dominant trees were sampled and standard dendrochronological methods were used to compare tree growth of both types of trees at each site. Climate-tree growth relationships were assessed using bootstrap correlations and response functions between tree-ring growth indices and climate variables, for both partials and full local chronologies of each stand, selecting climatic data from the most complete and closest meteorological stations. Our results showed that the trees selected for resin extraction were older, on average, and when site characteristics were favorable enough for maritime pine growth and resin extraction, all trees were resin-tapped. Contrastingly, when site characteristics were unfavorable for resin extraction, only the largest and the best-developed trees were tapped. No major differences were found between the climatic responses of resin-tapped and untapped trees, and it was therefore possible to use all the available tree-ring width series per site, both resin-tapped and untapped trees, to identify the main climatic drivers of maritime pine growth in central Spain. In addition, we have expanded the chronologies network of Pinus pinaster in Spain in number and length. This work may provide valuable information to improve forest management strategies for sustainable resin production.

Keywords: Resin Extraction, Tree-ring Width, Long-term Chronologies, Climate Response

iForest 17 (3): 148-155 (2024) - doi: 10.3832/ifor4458-017
https://iforest.sisef.org/contents/?id=ifor4458-017

Research Articles: Estimating the accuracy of smartphone app-based removal estimates against actual wood-harvesting data from clear cuttings

Vähä-Konka V, Korhonen L, Kärhä K, Maltamo M — 2024-05-14

Vähä-Konka V, Korhonen L, Kärhä K, Maltamo M

ESTIMATING THE ACCURACY OF SMARTPHONE APP-BASED REMOVAL ESTIMATES AGAINST ACTUAL WOOD-HARVESTING DATA FROM CLEAR CUTTINGS

Abstract: Trestima® is a computer vision-based smartphone application that utilises relascope theory to obtain estimates of forest attributes from smartphone photographs. The aim of this study was to investigate the accuracy of Trestima estimation and evaluate whether it is sufficiently accurate for operational use in forestry. Our data consisted of 37 forest stands, encompassing 73.5 ha in southeastern Finland, where Trestima estimates were obtained by forestry professionals during their work. The results were compared with harvester data obtained from clear-cut stands. The number of photographs taken per stand ranged between 1-29 (average: 7.3; standard deviation: 5.0). The total amount of industrial roundwood harvested from the stands was 21.531 m3 and the average harvest removal per hectare was 282 m3. The accuracy of Trestima estimation was relatively good when ≥ 10 photographs per stand were taken. In this case, the root mean square error percent (RMSE%) value associated with roundwood volume was 17.7%. When the number of photographs per stand was < 10, the accuracy of Trestima was much weaker (RMSE% 22.7-55.3%). On average, Trestima underestimated harvested volumes in Scots pine (Pinus sylvestris L.) stands (Bias% 11.4-89.2), although the bias was smaller (Bias% -12.7-12.4) with Norway spruce (Picea abies [L.] Karst.) stands. The Trestima smartphone application is a possible option for traditional field measurements in operational forestry, provided that its usage instructions are strictly followed, which is not always the case in practice.

Keywords: Forest Inventory, Forest Mensuration, Smartphone, Machine Vision, Computer Vision, Relascope, Harvester Data

iForest 17 (3): 140-147 (2024) - doi: 10.3832/ifor4377-017
https://iforest.sisef.org/contents/?id=ifor4377-017

Research Articles: How environmental factors condition natural regeneration in the altitudinal gradient of a montane rainforest

2024-05-04

Braga Rodrigues Duarte V, Abreu de Souza V, Machado Dias H, Horn Kunz S, Van Den Berg E

HOW ENVIRONMENTAL FACTORS CONDITION NATURAL REGENERATION IN THE ALTITUDINAL GRADIENT OF A MONTANE RAINFOREST

Abstract: The response of plant species to the variation in abiotic factors affects the regeneration capacity and, consequently, the structure of the forest community. This study aims to describe the structure of the regenerating stratum in a Brazilian montane rainforest and investigate its relationship with environmental and spatial variables along an altitudinal gradient. Data on the height and diameter at soil height of regenerating individuals and environmental variables were collected from 28 sample units, distributed in seven altitudinal sites. To understand the spatial influence on species distribution, spatial variables (MEMs - Moran’s Eigenvector Maps) were created based on geographic coordinates. Phytosociological parameters were calculated by species. Floristic similarity between the altitudinal quota was determined by the Bray-Curtis index (UPGMA), and the species that characterize each group were determined by the Indicator Species Analysis. Redundancy Analysis (RDA) was performed, and generalized linear models were adjusted to verify the influence of environmental and spatial factors on regenerating vegetation. The species Palicourea sessilis had the highest Importance Value in the regenerating community. Two floristic groups were formed: the highest sites (1420 to 1550 m a.s.l.) were floristically more similar to each other (Group 1) than to the sites in the 1112 to 1391 m elevation range (Group 2). Overall, 11 species were indicators of Group 1 and only one of Group 2. Finally, a pattern of species substitution was verified as a function of abiotic factors. The first two axes of the RDA explained 51.02% of the variation in the floristic composition of the regenerating community. Natural regeneration demonstrated environmental preferences, being influenced by luminosity, abundance in adult components, calcium and sodium contents, plant litter accumulation, altitude, and the spatial structure of the environment. Altitude did not seem to influence the pattern of abundance or richness of regenerating species.

Keywords: Environmental Variation, Species Distribution, Vegetation-Environment Relationship, Elevation, Understory

iForest 17 (3): 132-139 (2024) - doi: 10.3832/ifor4319-017
https://iforest.sisef.org/contents/?id=ifor4319-017

Research Articles: Development and evaluation of generalized fuel models for predicting fire behaviour in northern European heathlands

Minsavage-Davis CD, Davies GM, Haugum SV, Thorvaldsen P, Guri Velle L, Vandvik V — 2024-04-30

Minsavage-Davis CD, Davies GM, Haugum SV, Thorvaldsen P, Guri Velle L, Vandvik V

DEVELOPMENT AND EVALUATION OF GENERALIZED FUEL MODELS FOR PREDICTING FIRE BEHAVIOUR IN NORTHERN EUROPEAN HEATHLANDS

Abstract: Northern European heathlands and moorlands dominated by Calluna vulgaris are internationally recognized for their conservation importance while also supporting traditional, low-intensity agriculture and game hunting. Managed burning plays an important role in maintaining these ecosystems but climate and land-use changes, including planned or unplanned transitions to forest and woodland, are now resulting in concerns about increasing wildfire frequency, intensity and severity. In combination with rapidly-changing regulations surrounding managed burning, this has highlighted the need to understand current and potential future fuel structures to effectively model fire behaviour and develop evidence-based regulations surrounding managed burning. We developed standardized heathland fuel descriptions and modeled associated fire behaviour for heathlands in the UK (England, Scotland) and Norway. Utilizing existing fuel and biomass data, we used cluster analysis to identify five distinct fuel models and assessed how they were represented across C. vulgaris life-stages, geographic locations and EUNIS habitat-types. We validated their independence by examining predicted fire rates of spread based across three representative fire weather scenarios. Fire rates of spread differed between C. vulgaris life stages, regardless of EUNIS community or country. Mature stage and taller building stage fuels produced the highest fire rates of spread and early, shorter building and pioneer stage fuels produced the lowest. Moss and litter fuel loads proved to be important determinants of fire rate of spread in a high-risk fire weather scenario. An understanding of links between fuel types and potential fire behaviour can be used to inform management and policy decisions. To aid in this, we used classification tree analysis to link fuel types to easily-observable characteristics. This will facilitate pairing the fuel models with fire behaviour prediction software to make evidence-based assessments of management fire safety and wildfire risk.

Keywords: Calluna vulgaris, Fuelbed, Managed Burning, Mire, Rate Of Spread, Rothermel, Wildfire, Peatland

iForest 17 (2): 109-119 (2024) - doi: 10.3832/ifor4394-017
https://iforest.sisef.org/contents/?id=ifor4394-017

Research Articles: Distribution factors of the epiphytic lichen Lobaria pulmonaria (L.) Hoffm. at local and regional spatial scales in the Caucasus: combining species distribution modelling and ecological niche theory

Pshegusov R, Khanov Z, Chadaeva V — 2024-04-30

Pshegusov R, Khanov Z, Chadaeva V

DISTRIBUTION FACTORS OF THE EPIPHYTIC LICHEN LOBARIA PULMONARIA (L.) HOFFM. AT LOCAL AND REGIONAL SPATIAL SCALES IN THE CAUCASUS: COMBINING SPECIES DISTRIBUTION MODELLING AND ECOLOGICAL NICHE THEORY

Abstract: For the rare epiphytic lichen Lobaria pulmonaria (L.) Hoffm., there is a lack of data on ecological niche parameters and distribution factors in the Caucasus, which are necessary to develop an effective system of the species preservation during forest management. The aim of this study was to identify the influence of abiotic, biotic and movement factors on the potential distribution of Lobaria pulmonaria in the Caucasus forests, depending on the spatial scale. We combined species distribution modelling and ecological niche theory based on the BAM (Biotic-Abiotic-Movement) concept. A total of 174 occurrence data were retained in the modelling using Maxent ver. 3.4.3 in R. The distribution models of the main lichen phorophytes in the Caucasus (Pinus sylvestris L. and Fagus orientalis Lipsky) were used as biotic layers in models. The raster of distances from optimal sites, where the probability of the lichen occurrence remained above 0.5, was used as a movement-layer. Different abiotic predictors were significant in the lichen distribution in the Central Caucasus (terrain) and throughout the Caucasus (macroclimate). Interspecific relationships (lichen-phorophyte) were more significant at the local scale. The movement factor contributed most to the local model (80% of the contribution) and limited the lichen distribution to a radius of 20 m in the Central Caucasus and 30 m throughout the Caucasus. Field verification of the local model showed an 85.7% success rate of presence prediction with cutoff values of 0.8. The combination of SDM modelling and ecological niches theory is an effective method for studying the potential localisation and the ecological niches of epiphytic lichens.

Keywords: Lobaria pulmonaria, Caucasus Forest, Species Distribution Modelling, Ecological Niche, Biotic-Abiotic-Movement Concept, Spatial Scale

iForest 17 (2): 120-131 (2024) - doi: 10.3832/ifor4406-017
https://iforest.sisef.org/contents/?id=ifor4406-017

Research Articles: Assessing the influence of different Synthetic Aperture Radar parameters and Digital Elevation Model layers combined with optical data on the identification of argan forest in Essaouira region, Morocco

El Moussaoui EH, Moumni A, Lahrouni A — 2024-04-24

El Moussaoui EH, Moumni A, Lahrouni A

ASSESSING THE INFLUENCE OF DIFFERENT SYNTHETIC APERTURE RADAR PARAMETERS AND DIGITAL ELEVATION MODEL LAYERS COMBINED WITH OPTICAL DATA ON THE IDENTIFICATION OF ARGAN FOREST IN ESSAOUIRA REGION, MOROCCO

Abstract: Forest resource conservation necessitates a deeper understanding of forest ecosystem processes and how future management decisions and climate change may affect these processes. Argania spinosa (L.) Skeels is one of the most popular species in Morocco. Despite its ability to survive under harsh drought, it is endangered due to soil land removal and a lack of natural regeneration. Remote sensing offers a powerful resource for mapping, assessing, and monitoring the forest tree species at high spatio-temporal resolution. Multi-spectral Sentinel-2 and Synthetic Aperture Radar (SAR) time series combined with Digital Elevation Model (DEM) over the Argan forest in Essaouira province, Morocco, were subjected to pixel-based machine learning classification and analysis. We investigated the influence of different SAR data parameters and DEM layers on the performance of machine learning algorithms. In addition, we evaluated the synergistic effects of integrating remote sensing data, including optical, SAR, and DEM data, for identifying argan trees in the Smimou area. We collected data from Sentinel-2, Sentinel-1, SRTM DEM, and ground truth sources to achieve our goal. Testing different SAR parameters and integrating DEM layers of different resolutions with other remote sensing data showed that the Lee Sigma filter with a size of 11×11 and a DEM layer of 30 m resolution gave the best results using the Support Vector Machine algorithm. Significant improvements in overall accuracy (OA) and kappa index (K) were observed in the following phase. After applying a smoothing technique, the combined use of two Sentinel constellation products improved map accuracy and quality. For the best scenario (VV+NDVI), the OA was 88.32% (K = 0.85), while for scenarios NDVI+DEM and VH+NDVI+DEM, the OAs were 93.25% (K = 0.91) and 93.01% (K = 0.91), respectively. Integrating a DEM layer with SAR and optical data has significantly improved the accuracy in the classification of vegetation types, especially in our study area which is characterized by high environmental heterogeneity.

Keywords: Argan Forest, Sentinel-2, GLCM Texture, SAR Parameters, DEM, Satellite Image Classification

iForest 17 (2): 100-108 (2024) - doi: 10.3832/ifor4183-016
https://iforest.sisef.org/contents/?id=ifor4183-016

Research Articles: The missing part of the past, current, and future distribution model of Quercus ilex L.: the eastern edge

Yilmaz OY, Akkemik U, Dogan OH, Yilmaz H, Sevgi O, Sevgi E — 2024-03-22

Yilmaz OY, Akkemik U, Dogan OH, Yilmaz H, Sevgi O, Sevgi E

THE MISSING PART OF THE PAST, CURRENT, AND FUTURE DISTRIBUTION MODEL OF QUERCUS ILEX L.: THE EASTERN EDGE

Abstract: Ongoing climate change is anticipated to shift the geographical distribution range and impact local abundance of tree species by altering their ecological conditions. Given the lower resilience of populations at the species’ range edges, locally adapted range-edge populations are critical to the species’ survival under climate change. In this context, the distribution of holm oak (Quercus ilex L.) at the eastern border of its distribution range was assessed under current, past, and foreseeable future climate change scenarios, using species distribution models (SDMs). Current SDMs were developed using WorldClim 1.4 climate data as baseline at 30-second spatial resolution by using Generalized Boosted Regression Models (GBM) and showed moderate model performance. To compare temporal transferability and account for climate uncertainties of two versions of future climate data (CMIP5 and CMIP6), we used 4 Global Circulation Models (GCMs), 2 emission scenarios (moderate RCP45/SSP245 and pessimistic - RCP85/SSP585) for 2 different periods in the future (2040-2060 and 2060-2080). We also made predictions about the past (Mid-Holocene, about 6.000 years ago) using 4 CMIP5 GCMs. Most important variables of SDMs were distance to the sea, isothermality (BIO3), annual precipitation (BIO12), the mean temperature of driest quarter (BIO9), and the precipitation of driest month (BIO14). Our findings showed that the species’ potential distribution range probably used to be much wider in the mid-Holocene, which implies that the holm oak had a broader climatic niche during this period. The future projections indicate that its distribution area in the eastern border might increase particularly in the Black Sea region, while decreasing in the Aegean region resulting in a likely northward range shift in Turkey. However, other variables not included in our models such as land use changes might drive future shifts. Due to its high resistance to dry conditions and resilience, this species might continue to spread in southwestern Turkey in 2050s and 2070s. Finally, our study fills the gap in potential distribution predictions in context of climate change for the eastern boundary of the holm oak.

Keywords: Species Distribution Model, Global Circulation Models, Holm Oak, Turkey, Range Edge, Generalized Boosted Regression Models, Climate Change

iForest 17 (2): 90-99 (2024) - doi: 10.3832/ifor4350-016
https://iforest.sisef.org/contents/?id=ifor4350-016

Review Papers: Increasing resistance and resilience of forests, a case study of Great Britain

Leslie A, Wilson E, Park A — 2024-03-21

Leslie A, Wilson E, Park A

INCREASING RESISTANCE AND RESILIENCE OF FORESTS, A CASE STUDY OF GREAT BRITAIN

Abstract: The forests of Great Britain (GB) are an important resource, which are under threat from climate change and exotic pests and diseases. The forest sector has been proactive in launching initiatives and supporting activities to improve the resistance and resilience of forests in GB. These interventions can be directed at forests at a range of scales, from genetic to national. This article describes the range of potential and actual actions focused on adapting Britain’s forests to climate change and damage from pests and diseases. However, there are also barriers to improving the resilience of forests in GB and these are also discussed.

Keywords: Forests, Great Britain, Resistance, Resilience, Climate Change, Pests and Pathogens

iForest 17 (2): 69-79 (2024) - doi: 10.3832/ifor4552-017
https://iforest.sisef.org/contents/?id=ifor4552-017

Research Articles: Seedling quality and short-term field performance of three Amazonian forest species as affected by site conditions

Guimarães ZTM, Da Silva DC, Ferreira MJ — 2024-03-21

Guimarães ZTM, Da Silva DC, Ferreira MJ

SEEDLING QUALITY AND SHORT-TERM FIELD PERFORMANCE OF THREE AMAZONIAN FOREST SPECIES AS AFFECTED BY SITE CONDITIONS

Abstract: High quality seedlings are essential for the successful establishment of forest stands. Seedling quality can be assessed by the morphological attributes (e.g., height, diameter, dry mass, Dickson’s quality index) measured in the nursery phase. The defining, producing, and handling of seedlings can be based on specific characteristics suited to a site, as proposed by the Target Plant Concept. However, a target plant concept is an important research gap for Amazonian tree species. Here, we explore the associations between morphological attributes of seedlings in the nursery and determine the combined effect of the seedling quality attributes and site preparation methods on one-year field performance to define a range for nondestructive morphological attributes that can be associated with successful establishment for Amazonian commercial forest species - Bertholletia excelsa, Dipteryx odorata and Tachigali vulgaris. We measured morphological attributes in the nursery and analyzed the correlations to detect better predictors of destructive attributes. Then, we related these initial morphological attributes to survival and growth one year after planting in two site conditions: manual holing preparation and mechanical site preparation (subsoiling plus harrowing). We represent growth using different metrics: one-year size, absolute and relative growth rates in height and root collar diameter. Site conditions were assessed by soil physical properties. For all species, root collar diameter was a good predictor of destructive attributes that evaluated seedling quality, such as Dickson’s quality index. Site preparation methods resulted in different site qualities. Mechanical site preparation improved the total porosity and reduced the bulk density and resistance to penetration. Survival was not affected by initial attributes or site preparation methods. The initial attributes were poor predictors of field growth for D. odorata and T. vulgaris. The field performance of B. excelsa seedlings was affected by initial attributes, site, and the combination of both. The definition of a range for operational attributes according to site conditions is true only for B. excelsa. These results are important to help fill research gaps related to technical procedures to establish large-scale reforestation projects using Amazonian tree species.

Keywords: Plant Target Concept, Morphological Attributes, Mechanical Site Preparation, Subsoiling, Harrowing, Growth Rates

iForest 17 (2): 80-89 (2024) - doi: 10.3832/ifor4317-016
https://iforest.sisef.org/contents/?id=ifor4317-016

Review Papers: Prospects for evolution in European tree breeding

2024-03-06

Fugeray-Scarbel A, Bouffier L, Lemarié S, Sánchez L, Alia R, Biselli C, Buiteveld J, Carra A, Cattivelli L, Dowkiw A, Fontes L, Fricano A, Gion JM, Grima-Pettenati J, Helmersson A, Lario F, Leal L, Mutke S, Nervo G, Persson T, Rosso L, Smulders Marinus J, Steffenrem A, Vietto L, Haapanen M

PROSPECTS FOR EVOLUTION IN EUROPEAN TREE BREEDING

Abstract: Genetically improved forest reproductive materials are now widely accessible in many European countries due to decades of continuous breeding efforts. Tree breeding does not only contribute to higher-value end products but allows an increase in the rate of carbon capture and sequestration, helping to mitigate the effects of climate change. The usefulness of breeding programmes depends on (i) the relevance of the set of selected traits and their relative weights (growth, drought tolerance, phenology, etc.); (ii) the explicit management of targeted and “neutral” diversity; (iii) the genetic gain achieved; and (iv) the efficiency of transferring diversity and gain to the plantation. Several biological factors limit both operational breeding and mass reproduction. To fully realise the potential of tree breeding, the introduction of new technologies and concepts is pivotal for overcoming these constraints. We reviewed several European breeding programmes, examining their current status and factors that are likely to influence tree breeding in the coming decades. The synthesis was based on case studies developed for the European Union-funded B4EST project, which focused on eight economically important tree species with breeding histories and intensities ranging from low-input breeding (stone pine, Douglas-fir and ash) to more complex programmes (eucalyptus, maritime pine, Norway spruce, poplar, and Scots pine). Tree breeding for these species is managed in a variety of ways due to differences in species’ biology, breeding objectives, and economic value. Most programmes are managed by governmental institutes with full or partial public support because of the relatively late return on investment. Eucalyptus is the only tree species whose breeding is entirely sponsored and managed by a private company. Several new technologies have emerged for both phenotyping and genotyping. They have the potential to speed up breeding processes and make genetic evaluations more accurate, thereby reducing costs and increasing genetic gains per unit of time. In addition, genotyping has allowed the explicit control of genetic diversity in selected populations with great precision. The continuing advances in tree genomics are expected to revolutionise tree breeding by moving it towards genomic-based selection, a perspective that requires new types of skills that are not always available in the institutions hosting the programmes. We therefore recognise the importance of promoting coordination and collaboration between the many groups involved in breeding. Climate change is expected to bring in new pests and diseases and increase the frequency of extreme weather events such as late frosts and prolonged droughts. Such stresses will cause slow growth and mortality, reducing forest productivity and resilience. Most of these threats are difficult to predict, and the time-consuming nature of conventional breeding does not allow for an adequate and timely reaction. We anticipate that most breeding programmes will need to revise their selection criteria and objectives to place greater emphasis on adaptive performance, tolerance to multiple environmental stresses, stability in different environments, and conservation of genetic diversity. Testing breeding materials in a variety of environments, including potentially contrasting climates, will become increasingly important. Climate change may also force the incorporation of new genetic resources that provide new useful adaptations, which may involve the use of new, previously unexplored gene pools or hybridisation, with the enormous challenge of incorporating useful alleles without adding along an unfavourable genetic background. Decision-support tools to help landowners and foresters select the best-performing forest reproductive material in each specific environment could also help reduce the impact of climate change.

Keywords: Tree Breeding, Breeding Programmes, Breeding Strategies, Climate Change, Seed Orchards, Genomic Selection

iForest 17 (2): 45-58 (2024) - doi: 10.3832/ifor4544-017
https://iforest.sisef.org/contents/?id=ifor4544-017

Research Articles: The growth dynamics of East European Scots pine (Pinus sylvestris L.) populations - a Lithuanian field trial

2024-03-06

Linkevičius E, Šidlauskas G, Kliučius A, Armoška E, Mikalajunas M, Sidabriene D, Andriuškevičiute P, Augustaitis A

THE GROWTH DYNAMICS OF EAST EUROPEAN SCOTS PINE (PINUS SYLVESTRIS L.) POPULATIONS - A LITHUANIAN FIELD TRIAL

Abstract: For the native Lithuanian Scots pine (Pinus sylvestris L.) population, rapidly changing climatic conditions raise new issues, related to survivability and resistance of local provenances to biotic and abiotic stressors. The aim of this study is to revise and update the findings of Abraitis & Ericsson (1996) who assessed the productivity of Scots pine provenances following 22 years of growth. In this study, we assessed the productivity of same provenances following 39 years of growth. This study was done based on a long-term pine provenance research experiment established in 1975 in Lithuania, as an integral part of the Prokazyn investigation that was launched across the former USSR. Our results indicate a clear effect of latitude as well as longitude on the mean stand performance values of Scots pine provenances. With increasing latitude, mean height, mean quadratic diameter and the volume of growing trees per hectare had a clear decreasing tendency. Except for the mean squared diameter, the impact of the longitude was the same on the mean stand height and the volume of growing trees per hectare. Ranking of Scots pine provenances based on breeding indices showed that provenances that were identified as the most productive ones by Abraitis & Ericsson (1996) after 17 years of growth, lost their top positions after 39 years of growth. In the case of demand for genetically improved planting material, it could be recommended to use southerner populations which demonstrate higher growth intensity up to 39 years.

Keywords: Scots Pine Provenances, Latitude, Longitude, Radial Growth, Seasonal Effects, Climatic Indicators

iForest 17 (2): 59-68 (2024) - doi: 10.3832/ifor4359-016
https://iforest.sisef.org/contents/?id=ifor4359-016

Research Articles: Relationship between microbiological, physical, and chemical attributes of different soil types under Pinus taeda plantations in southern Brazil

2024-02-28

Zanon JA, Marques R, Herzog de Carvalho D, Larsen JG, De Souza Kulmann MS, Schumacher MV

RELATIONSHIP BETWEEN MICROBIOLOGICAL, PHYSICAL, AND CHEMICAL ATTRIBUTES OF DIFFERENT SOIL TYPES UNDER PINUS TAEDA PLANTATIONS IN SOUTHERN BRAZIL

Abstract: Over the last decades, Pinus taeda L. plantations in southern Brazil showed a great increase in average production. However, the gains in productivity obtained by genetic selection and breeding have nowadays stabilized. Research on edaphic factors and silvicultural practices is currently performed with the aim of both increasing the productivity of P. taeda plantations and maintaining the soil quality. To this end, soil microbiological attributes are considered better indicators of soil quality as they are more sensitive than chemical and physical ones. In this study, we aimed to evaluate the relationship between microbial activity and the physical and chemical parameters of different soil types under young Pinus taeda plantations at five different sites in southern Brazil. Soil samples were collected at depths of 0-5 and 5-10 cm. The soil microbiological attributes evaluated were: potentially mineralizable nitrogen (PMN), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial basal respiration (MBR), and metabolic quotient (qCO2). We also evaluated some physical and chemical soil parameters. Sites with the highest values of C, clay, and nutrients in the soil, showed higher values for the soil microbiological attributes, compared to the other study sites. The previous management with minimal tillage in some sites seems to positively affect soil quality. The MCB and MBR showed better sensitivity in indicating differences between sites and showed a good relationship with clay content, C/N ratio, K, and pH. These results suggest that site-specific characteristics such as soil type or forest management influence soil microbiological attributes in Pinus taeda plantations during initial growth in southern Brazil.

Keywords: Soil Microbial Activity, Microbial Biomass Carbon, Microbial Basal Respiration, Forest Management

iForest 17 (1): 29-35 (2024) - doi: 10.3832/ifor4349-016
https://iforest.sisef.org/contents/?id=ifor4349-016

Research Articles: Analyzing regression models and multi-layer artificial neural network models for estimating taper and tree volume in Crimean pine forests

Sahin A — 2024-02-28

Sahin A

ANALYZING REGRESSION MODELS AND MULTI-LAYER ARTIFICIAL NEURAL NETWORK MODELS FOR ESTIMATING TAPER AND TREE VOLUME IN CRIMEAN PINE FORESTS

Abstract: The taper and merchantable tree volume equations are the most used models in forestry because of their accuracy in estimating both total and merchantable tree volume. However, numerous studies reported that artificial neural network models show fewer errors and a greater success rate as compared to regression models. This study used data from 200 Crimean pine trees in Turkey’s Central Anatolia and Mediterranean Region to assess the performance of artificial neural network (ANN) models and the Max-Burkhart’s equation for estimating taper and merchantable tree volume. The most accurate results were obtained using 3 hidden layers and 10 neurons in the taper model and 1 hidden layer and 100 neurons in the volume model. The hyperbolic tangent sigmoid function was used for the ANN analysis and hyper-parameter customization. Using the ANN model with hyper-parameter customization, the AAE in the Max-Burkhart taper model decreased from 9.315 to 6.939 (-25.5%), the RMSE decreased from 3.072 to 2.656 (-13.5%), and the FI increased from 0.964 to 0.966 (+1.23%). Similarly, using the ANN model with hyper-parameter customization, the AAE in the Max-Burkhart volume model decreased from 0.056 to 0.013 (-76.6%), the RMSE decreased from 0.247 to 0.12 (-51.6%), and the FI increased from 0.909 to 0.979 (+7.69%). Our results showed that the ANN models’ predictions were more accurate and reliable compared to the Max-Burkhart’s equations. We resolved overfitting via hyper-parameter modification, which also allowed for monitoring the impact of error and prediction outputs at various learning rates. It was also possible to develop tree taper and volume equations with lower error rates in both training and validation data, consistent with tree growth trends in both data sets.

Keywords: Compatible Tree Taper, Merchantable Volume Equations, Crimean Pine, Multilayer Artificial Neural Network, Hyper-parameter Customization

iForest 17 (1): 36-44 (2024) - doi: 10.3832/ifor4449-017
https://iforest.sisef.org/contents/?id=ifor4449-017

Research Articles: Exploring machine learning modeling approaches for biomass and carbon dioxide weight estimation in Lebanon cedar trees

Diamantopoulou MJ, Çömez A, Özçelik R, Güner ST — 2024-02-12

Diamantopoulou MJ, Çömez A, Özçelik R, Güner ST

EXPLORING MACHINE LEARNING MODELING APPROACHES FOR BIOMASS AND CARBON DIOXIDE WEIGHT ESTIMATION IN LEBANON CEDAR TREES

Abstract: Accurate estimates of total tree biomass are of critical importance to obtain reliable estimation of the carbon dioxide weight sequestered from the atmosphere by trees and forest stands. This information has the potential to guide appropriate forest management decisions which allow for both the improvement of forest sustainability and the implementation of multi-task reforestation designs aimed to mitigate the detrimental effects of climate change. The current laborious and tree-destructive procedures needed to attain such information has led to the development of machine learning (ML) models aimed at providing accurate estimations of the tree biomass sequestering the atmospheric carbon dioxide. We tested the Levenberg-Marquardt artificial neural network and the support vector machine for regression techniques as an alternative to non-linear allometric regression (NLR) modelling approaches commonly used for tree biomass estimation. We tested the developed ML models using primary ground-truth data from the Lebanon cedar forests in the Western Inner Anatolian regions of Turkey, and their predictions were compared to those of NLR models developed using the same dataset. The results showed that the ML approaches outperformed the NLR models in accurately estimating tree biomass and its components (above- and belowground dry biomass, dry branches biomass, etc.), and the support vector regression (SVR) models gave the highest accuracy of estimates. Therefore, the carbon dioxide weight sequestered in Lebanon cedar trees were reliably estimated, with the aim of supporting the best forest management practices to be applied in Lebanon cedar tree stands in Turkey.

Keywords: Tree Biomass, Carbon Dioxide Weight, Levenberg-Marquardt Artificial Neural Network, Support Vector Machine For Regression, Lebanon Cedar Trees

iForest 17 (1): 19-28 (2024) - doi: 10.3832/ifor4328-016
https://iforest.sisef.org/contents/?id=ifor4328-016

Research Articles: Use of brassinosteroids to overcome unfavourable climatic effects on seed germination in Pinus nigra J. F. Arnold

Suraweera PA, Kuneš I, Baláš M, Podrázský V, Šulitka M, Remeš J — 2024-02-02

Suraweera PA, Kuneš I, Baláš M, Podrázský V, Šulitka M, Remeš J

USE OF BRASSINOSTEROIDS TO OVERCOME UNFAVOURABLE CLIMATIC EFFECTS ON SEED GERMINATION IN PINUS NIGRA J. F. ARNOLD

Abstract: Seeds of forest species can show germination and survival problems if they are exposed to adverse climatic conditions in the course of germination. Brassinosteroids could help seeds to overcome such environmental stress. We tested the effects of exogenous application of a chosen brassinosteroid compound 2α,3α,17β-trihydroxy-5α-androstan-6-one on the germination capacity and germination energy of European black pine (Pinus nigra J. F. Arnold) seeds. Before germination, the seeds were soaked for 24 hours either in demineralised water (control treatment) or in brassinosteroid solutions of four concentrations (high, higher-medium, lower-medium and low-concentration treatments). In the course of germination, the control and all four concentration treatments were subjected to two alternative temperature regimes: the optimal (unstressed) regime (20/30°C) and the stress regime, during which the seeds were exposed to temporary temperature stress (peaking at 42°C). In the optimal temperature regime, the highest germination energy was recorded in the higher-medium-concentration treatment and a significantly increased germination energy when compared to the control was also observed in a high-concentration treatment. The brassinosteroid, when applied in high, higher-medium and lower-medium concentrations, significantly increased the germination capacity compared to the control. The highest germination capacity was recorded in the high-concentration treatment. The temperature stress substantially reduced the germination of P. nigra. In the stress regime, the seeds of the higher-medium-concentration treatment decidedly showed the highest germination energy and capacity and those of the control treatment the lowest. The seed germination energy in the control was significantly lower than that recorded in the high and higher-medium-concentration treatments. The seed germination capacity in the control was significantly lower than those found in all concentration treatments, except for the seeds in the low-concentration treatment. The brassinosteroid application promoted the germination of black pine and partly alleviated the impact of the temporary heat stress. However, this application did not compensate for the heat stress effects completely. The potential for the use of the brassinosteroid may exist chiefly for seedings of Pinus nigra in forest nurseries where the nursery staff try to maintain optimal climatic conditions, and deviations from these conditions are usually only temporary.

Keywords: Brassinosteroids, Pinus nigra, Germination Capacity, Germination Energy, Germination Rate

iForest 17 (1): 1-9 (2024) - doi: 10.3832/ifor4340-016
https://iforest.sisef.org/contents/?id=ifor4340-016

Research Articles: Forest fire occurrence modeling in Southwest Turkey using MaxEnt machine learning technique

Göltas M, Ayberk H, Kücük O — 2024-02-02

Göltas M, Ayberk H, Kücük O

FOREST FIRE OCCURRENCE MODELING IN SOUTHWEST TURKEY USING MAXENT MACHINE LEARNING TECHNIQUE

Abstract: Climate anomalies and potential increased human pressure will likely cause the increase in frequency and damage of forest fires in the near future. Therefore, accurately and temporally estimating and mapping forest fire probability is necessary for preventing from destructive effects of forest fires. In this study, the forest fire occurrence in Southwestern Turkey was modeled and mapped with the maximum entropy (MaxEnt) approach. We used past fire locations (from 2008 to 2018) with environmental variables such as fuel type, topography, meteorological parameters, and human activity for modeling and mapping, using data that could be obtained quickly and easily. The performances of fire occurrence models was quite satisfactory (AUC: range from 0.71 to 0.87) in terms of the model reliability. When the fire occurrence models were analyzed in detail, it was seen that the environmental variables with the highest gain when used alone were the maximum temperature, tree species composition, and distance to agricultural lands. To evaluate the models, we compared the fire locations between 2019 and 2020 with those on reclassified fire probability maps. Fire location from 2019-2020 fit substantially within the model fire occurrence predictions since many fire points in high or extreme fire probability categories has been observed. The results of this study can be a guideline for the Mediterranean forestry that has consistently struggled the forest fires and attempted to manage effectively forest lands at fire risk.

Keywords: Turkey, Fire Ignition, Fire Risk, Maximum Entropy, Machine Learning

iForest 17 (1): 10-18 (2024) - doi: 10.3832/ifor4321-016
https://iforest.sisef.org/contents/?id=ifor4321-016

Research Articles: How biomass and other tree architectural characteristics relate to the structural complexity of a beech-pine forest

Seidel D, Böttger FA — 2023-12-19

Seidel D, Böttger FA

HOW BIOMASS AND OTHER TREE ARCHITECTURAL CHARACTERISTICS RELATE TO THE STRUCTURAL COMPLEXITY OF A BEECH-PINE FOREST

Abstract: The provision of ecosystem functions and services in forests is closely linked to the presence of complex structures. One such service is the ability to store carbon. It has recently become possible to quantify both structural complexity and biomass of forests (as proxy of carbon storage) using light detection and ranging (LiDAR). The objective of this study was to analyze how the community-level complexity of a forest stand relates to structural characteristics, and biomass in particular, of the trees comprising the stand. To do so, we virtually assembled 30 forests (3D models), all representing different versions of a beech-pine forest in Germany, based on real world 3D LiDAR scan data of all trees in the forest. At the individual tree level, various structural characteristics, including wood volume and biomass were derived using both voxel models and quantitative structure models (QSM). Basal area and biomass, as well as to a lower degree also the mean height of maximum crown projection area, significantly affected the structural complexity at stand level. Among the different forest models, the variation in complexity could best be described using a combination of basal area, mean height of the maximum crown projection area, and the coefficient of variation of total tree height. Biomass alone explained 54% of the variation in stand-level complexity, while the multivariate model based on measures addressing the amount and vertical distribution of plant material explained 86% of the variability in complexity. Using a laser-based and holistic approach of assessing the structural complexity, namely the box-dimension, allowed identifying key structural attributes that promote aboveground structural complexity of the forest studied here.

Keywords: LiDAR, 3D Forest Model, Mobile Laser Scanning, Pine-beech Forest, Mixed Forest, Structural Complexity

iForest 16 (6): 368-376 (2023) - doi: 10.3832/ifor4305-016
https://iforest.sisef.org/contents/?id=ifor4305-016

Research Articles: Effects of silvicultural thinning on stand structure and coarse woody debris in the deciduous Arasbaran forest, Iran

Ghanbari S, Sefidi K, Álvarez-Álvarez P, Fathizadeh O, Abbasnezhad Alchin A — 2023-12-19

Ghanbari S, Sefidi K, Álvarez-Álvarez P, Fathizadeh O, Abbasnezhad Alchin A

EFFECTS OF SILVICULTURAL THINNING ON STAND STRUCTURE AND COARSE WOODY DEBRIS IN THE DECIDUOUS ARASBARAN FOREST, IRAN

Abstract: Forest stand structure is influenced by artificial factors such as silvicultural activities, and by natural factors such as wildfires, floods, windstorms, diseases, and insect infestations. The silvicultural treatments used during the transformation of coppice to the coppice-with-standard system are a main source of coarse woody debris (CWD). Even small changes in the amounts and/or types of CWD can threaten forest biodiversity, including plant and bird diversity. In this study, we compared managed and unmanaged forest stands in Northwest Iran to better understand changes in species composition and stand characteristics (with particular reference to CWD) in relation to silvicultural practices. In total, thirty-six 0.5-hectare sampling plots were surveyed (total area: 18 ha). We found significant differences between the cut (active management) and uncut areas (proforestation) in indices of height, number of tree species, canopy cover of live and fallen trees, dead tree density, and relative frequency of dead trees. The sample plots included 22 species of live trees, and the CWD was generated by 16 of these species. The number of stems of live trees in the sample plots was 2.653 (SE = 181), with Carpinus orientalis accounting for the highest mean density of live trees. C. orientalis also provided the highest total frequency of downed logs (70%) in the stands, followed by Quercus macranthera (20%). Q. macranthera accounted for the highest relative frequency of dead trees in the stands. In total, around 42% of the CWD consisted of logs lying on the forest floor, followed by dead trees (39%) and stumps (19%). Most of the CWD was included in decay class (DC) 2 (71.6%), followed by DC1 (16.7%) and DC3 (11.3%). Forest managers must balance the amount of CWD, especially from dead trees, in these stands to conserve the diversity of the material in terms of both decay class and tree species.

Keywords: Coppice-with-standard System, Quercus macranthera, Silvicultural Activities, Structural Characteristics, Tree Removal

iForest 16 (6): 377-384 (2023) - doi: 10.3832/ifor4312-016
https://iforest.sisef.org/contents/?id=ifor4312-016

Research Articles: Performance assessment of two plotless sampling methods for density estimation applied to some Alpine forests of northeastern Italy

Notarangelo M, Carrer M, Lingua E, Puletti N, Torresan C — 2023-12-19

Notarangelo M, Carrer M, Lingua E, Puletti N, Torresan C

PERFORMANCE ASSESSMENT OF TWO PLOTLESS SAMPLING METHODS FOR DENSITY ESTIMATION APPLIED TO SOME ALPINE FORESTS OF NORTHEASTERN ITALY

Abstract: In this study, we tested two plotless sampling methods, the ordered distance method and point-centred quarter method, to estimate the tree density and basal area in some managed Alpine forests in northeastern Italy. We selected nine independent forest stands, classified according to the spatial distribution patterns of trees (cluster, random, regular). A plotless sampling survey was simulated within the selected stands and the tree density and basal area were estimated by applying both the ordered distance method and point-centred quarter method. We compared the estimates, in terms of accuracy and precision, between the two methods and against estimates obtained from a simulated survey based on a plot-based sampling method. The point-centred quarter method outperformed the ordered distance method in terms of both accuracy and precision, showing higher robustness towards the bias related to non-random spatial patterns. However, both the plotless methods we tested can provide unbiased accuracy of estimates which, in addition, do not differ from estimates of plot-based sampling. The satisfactory results are encouraging for further tests over other Italian Alpine as well as Apennine forests. If confirmed, the plotless sampling method, especially the point-centred quarter method, could represent an effective alternative whenever plot-based sampling is deemed redundant, or expensive.

Keywords: Distance-based Density Estimator, Ordered Distance Method, Point-centred Quarter Method, Accuracy, Precision, Conditional Inference Trees, Forest Monitoring

iForest 16 (6): 385-391 (2023) - doi: 10.3832/ifor4335-016
https://iforest.sisef.org/contents/?id=ifor4335-016

Research Articles: Variations in the performance of hybrid poplars subjected to the inoculation of a microbial consortium and water restriction

Yáñez MA, Espinoza S, Ovalle J, Magni C, Martínez-Herrera E — 2023-12-13

Yáñez MA, Espinoza S, Ovalle J, Magni C, Martínez-Herrera E

VARIATIONS IN THE PERFORMANCE OF HYBRID POPLARS SUBJECTED TO THE INOCULATION OF A MICROBIAL CONSORTIUM AND WATER RESTRICTION

Abstract: There is an increasing interest in using plant growth-promoting rhizobacteria (PGPR) to improve hybrid poplar performance under water stress conditions. We assessed the growth and leaf-level physiological responses of different hybrid poplar clones to the inoculation of a microbial consortium and subjected to moderate water shortage. In a nursery experiment, growth, leaf gas exchange, and biomass partitioning traits were assessed during one growing season on twenty hybrid clones from interspecific crosses of Populus trichocarpa × P.deltoides and (P. trichocarpa × P. deltoides) × P. deltoides, which were submitted to two treatments of PGPM inoculation (Inoculated, Inoc_1 vs. non-inoculated, Inoc_0) and two irrigation treatments (full water vs. water restriction). The water restriction decreased shoot growth, photosynthetic rate (Asat), and stomatal conductance (gs); increased intrinsic water use efficiency (WUEint) of the hybrid clones but it did not change the root-to-shoot ratio. Unlike our expectations, by the end of the study, treatment Inoc_1 slightly decreased basal diameter (D) and height (H) relative to Inoc_0 (5.8% and 5.2 %, respectively). Moreover, seven clones significantly decreased the root biomass by 37% to 62% in the Inoc_1 relative to Inoc_0 treatment, while the other clones showed no response to the inoculation. Oppositely, while most of the clones showed no response to the Inoc_1 treatment on leaf-physiological traits compared to Inoc_0, some of them exhibited an increase of Asat of 15% to 39%. Overall, the consortium applied did not improve the responses to the water restriction, and responses to the inoculation were more associated with a deleterious than a growth-promoting effect, which is discussed in the context of nutrient immobilization, application method, and timing.

Keywords: Biomass Partitioning, Leaf-physiological Traits, PGPM Inoculation, Poplar Clones, Water Stress

iForest 16 (6): 352-360 (2023) - doi: 10.3832/ifor4378-016
https://iforest.sisef.org/contents/?id=ifor4378-016

Technical Advances: A WebGIS tool to support forest management at regional and local scale

Cadez L, Giannetti F, De Luca A, Tomao A, Chirici G, Alberti G — 2023-12-13

Cadez L, Giannetti F, De Luca A, Tomao A, Chirici G, Alberti G

A WEBGIS TOOL TO SUPPORT FOREST MANAGEMENT AT REGIONAL AND LOCAL SCALE

Abstract: One of the most important obstacles for taking advantage of forest resources in the Italian Alps is represented by the high level of private properties fragmentation and by their small size. Thus, there is an urgent need for tools to support single or multi-forest owners to gain reliable and updated information on their forest stands so that the proper silvicultural activities following all the existing regulations can be adopted. The present research was aimed at promoting a shared management of small private forest properties in the mountainous area of Friuli Venezia Giulia (NE Italy) through the implementation of a new WebGIS tool to support forest decisions and management at different spatial scales. This new tool was developed updating and merging together different available information sources (e.g., tree species composition, the presence of protected areas, forest roads, etc.) with ad-hoc elaborated layers (e.g., standing volume, annual increment of volume, forest accessibility, etc.), also elaborating a cost analysis related to the different possible harvesting methods. The tool allows queries at the level of either a single or a group of cadastral parcels to obtain data in a format, which can be used for filling in the planning document requested by the regional authorities.

Keywords: Forest Decision Support System, WebGIS, Forestry, Accessibility, Volume Estimation

iForest 16 (6): 361-367 (2023) - doi: 10.3832/ifor4445-016
https://iforest.sisef.org/contents/?id=ifor4445-016

Research Articles: Ectomycorrhizal diversity in a mature pedunculate oak stand near Morović, Serbia

2023-11-22

Milović M, Kovačević B, Drekić M, Pilipović A, Pekeč S, Kesić L, Dilas M, Karaklić V, Galić Z

ECTOMYCORRHIZAL DIVERSITY IN A MATURE PEDUNCULATE OAK STAND NEAR MOROVIć, SERBIA

Abstract: Pedunculate oak is among the most economically important deciduous forest tree species in Europe and is also a host for many important ectomycorrhizal (ECM) fungi. The aim of this study was to analyse the ECM fungal community in a mature pedunculate oak stand near Morović, Serbia in spring and autumn. ECM fungi were determined by combining morpho-anatomical characterization of ectomycorrhizas with molecular analysis based on PCR amplification of the internal transcribed spacer region of fungal nuclear ribosomal DNA. The number of ECM fungal taxa and the number of different categories of fine roots were counted, diversity indices were calculated, and ECM fungi were classified into exploration types. Twenty-one ECM fungal taxa were recorded in the studied mature pedunculate oak stand, 19 in spring and 13 in autumn. ECM communities consisted of one dominant taxon and a larger number of rare taxa. Lactarius quietus was the most abundant ECM fungus in both seasons which made association with more than half of ECM root tips. At the stand near Morović, contact exploration type (ET) dominated, short-distance ET was less abundant, while medium-distance fringe ET and long-distance ET were rare in both seasons. The most pronounced difference between seasons is recorded in the number of ECM fungal taxa. The number of ECM fungal taxa and diversity indices recorded in the studied pedunculate oak stand were lower or similar compared to values obtained in stands of oak species across Europe.

Keywords: Ectomycorrhizal Fungi, Quercus robur L., Morpho-Anatomical Characterization, ITS Region

iForest 16 (6): 345-351 (2023) - doi: 10.3832/ifor4362-016
https://iforest.sisef.org/contents/?id=ifor4362-016

Research Articles: Trends and driving forces of spring phenology of oak and beech stands in the Western Carpathians from MODIS times series 2000-2021

Bucha T, Koren M, Sitková Z, Pavlendová H, Snopková Z — 2023-11-19

Bucha T, Koren M, Sitková Z, Pavlendová H, Snopková Z

TRENDS AND DRIVING FORCES OF SPRING PHENOLOGY OF OAK AND BEECH STANDS IN THE WESTERN CARPATHIANS FROM MODIS TIMES SERIES 2000-2021

Abstract: This study focused on trends and driving forces of the leaf unfolding (LU) onset of oak and beech forests in the Slovak Carpathians along elevational gradients in the period 2000-2021. Particular attention was paid to improving the modelling of the LU onset using the MOD/MYD09 Moderate Resolution Imaging Spectroradiometer (MODIS) products. The LU onset was derived from the annual Normalized Difference Vegetation Index (NDVI) trajectories fitted with a double logistic function. An improved estimate of the onset was obtained by calculating 6 parameters of the logistic function and by comparing with the LU onset from phenological field observations. Between 2000 and 2021, we found a trend towards an earlier LU onset at the national level by ~0.39 day year-1 for oak stands (p = 0.13) and ~0.08 day year-1 for beech stands (p = 0.48). The analysis of trends in three elevation zones showed a difference in the LU onset of oak and beech stands as a function of elevation. For oak in 100-350 and 350-500 m zones was found a shift towards an earlier onset by ~0.41 day year-1 (p = 0.12). This corresponds to a shift of 8.6 days for the entire observation period 2000-2021. In the elevational zone above 500 m, the trend was milder, ~0.27 day year-1 (p = 0.21), i.e., 5.6 days for the entire analysed period. The shift towards an earlier onset at lower elevations and a later onset at higher elevations for beech was not statistically significant, with p-values between 0.44 and 0.51. The atypical year 2021, with the latest onset of LU during the entire observation period, fundamentally affected the significance of all trends. Nevertheless, the pixel-level analysis revealed a significant trend towards an earlier LU onset (p < 0.05) in 20.3% of oak stands. The same result was found only in 0.8% of beech stands. Strong negative correlations with R2 = 0.72 for oak and R2 = 0.81 for beech (p < 0.001) were found between the LU onset and March and April temperature deviations from the long-term normal. Temperature changes are the main driving force affecting the LU onset in the studied region.

Keywords: MODIS, NDVI, Oak, Beech, Leaf Unfolding, Double Logistic Function, Phenometric Trends, Air Temperature

iForest 16 (6): 334-344 (2023) - doi: 10.3832/ifor4121-016
https://iforest.sisef.org/contents/?id=ifor4121-016

Commentaries & Perspectives: Key information for forest policy decision-making - Does current reporting on forests and forestry reflect forest discourses?

Linser S, Lier M, Bastrup-Birk A — 2023-11-15

Linser S, Lier M, Bastrup-Birk A

KEY INFORMATION FOR FOREST POLICY DECISION-MAKING - DOES CURRENT REPORTING ON FORESTS AND FORESTRY REFLECT FOREST DISCOURSES?

Abstract: Forest discourses help identify forest-related issues. They aim to aid policy and decision-makers in understanding forest-related challenges and opportunities better so that they may initiate possible strategies and tactics to tackle them. Ideally, information requirements for the forest discourses would be translated into measurable variables, being the basis for collecting, analysing, and reporting data and information. Our study examined the connection between major international forest reporting processes and forest discourses. We analysed summaries and key findings for policy makers of five recent major forest reports. We compared their focus with forest discourses on climate change, forest conservation, deforestation, forest decline, illegal logging, industrial forestry/bioeconomy, traditional knowledge, woody biomass production, and innovative wood-based biofuels. The paper explores how the forest discourses are reflected in the surveyed documents and closely examines the specific focus areas in the summaries for policy makers. The results show that most forest discourses are generally well-represented, albeit with different foci. The discourse on illegal logging could not be identified in any investigated documents, even though it remains a significant concern for international forest policy. Keywords related to traditional knowledge and woody biomass production could not be found in two of the analysed findings. All analysed summaries and key findings mention issues related to the climate change discourse topic. However, they lack information on emissions from deforestation, carbon dioxide emissions and carbon budgets, which are high in political discussions. The paper highlights how discourse issues have gained in complexity both topic-wise and regarding the reporting obligations, as policy and decision-makers require more timely and comprehensive information about the status’ and trends of forests.

Keywords: Forest Data, Forest Information, Forest Reporting, Forest Discourse, Forest Policy

iForest 16 (6): 325-333 (2023) - doi: 10.3832/ifor4457-016
https://iforest.sisef.org/contents/?id=ifor4457-016

Research Articles: Effects of arbuscular mycorrhizal fungi on microbial activity and nutrient release are sensitive to acid deposition during litter decomposition in a subtropical Cinnamomum camphora forest

Wu C, Kong X, He X, Lin Y, He Z, Gao Y, Kong Q — 2023-11-13

Wu C, Kong X, He X, Lin Y, He Z, Gao Y, Kong Q

EFFECTS OF ARBUSCULAR MYCORRHIZAL FUNGI ON MICROBIAL ACTIVITY AND NUTRIENT RELEASE ARE SENSITIVE TO ACID DEPOSITION DURING LITTER DECOMPOSITION IN A SUBTROPICAL CINNAMOMUM CAMPHORA FOREST

Abstract: Arbuscular mycorrhizal fungi (AMF) play an important role on litter decomposition, which is increasing suffering the negative impact of acid deposition. In this study, we investigated the AMF effects on litter decomposition via suppressing AMF and simulating acid deposition in a subtropical Cinnamomum camphora forest. The results showed that acid deposition and AMF suppression decelerated C. camphora leaf litter decomposition, especially at late decomposition stage; soil water content was the main factor restricting early-stage decomposition. The inhibiting effect of acid deposition was enhanced with acid intensity increase and AMF suppression aggravated the negative effect of acid stress on decomposition. Nitrogen-cycling enzymatic activity was significantly higher in later than in early decomposition stage, and acid deposition and AMF suppression significantly decreased microbial activity. Despite the seasonal effect was overwhelming, we still detected the effects of acid deposition and AMF suppression on litter nutrient release. Without or under low acid deposition, AMF suppression significantly increased organic matter and decreased alkali-hydrolyzable nitrogen content of detritusphere soil. Acid deposition significantly reduced soil organic matter content, while high acid deposition intensity increased alkali-hydrolyzable nitrogen content after 2- and 12-month decomposition, and decreased it at other months. Both acid deposition and AMF suppression decreased available phosphorus content, but did not affect phosphatase activity. AMF effects on invertase and nitrogen-release enzyme activities, and alkali-hydrolyzable nitrogen and available phosphorus contents of detritusphere soil were highly sensitive to acid deposition. Our results revealed that AMF effects on microbial activity and nutrient release during litter decomposition are sensitive to acid deposition.

Keywords: Litter Decomposition, Arbuscular Mycorrhizal Fungi, Acid Deposition, Extracellular Enzyme Activity, Detritusphere Soil Nutrients

iForest 16 (6): 314-324 (2023) - doi: 10.3832/ifor4324-016
https://iforest.sisef.org/contents/?id=ifor4324-016

Research Articles: Fungal and bacterial communities in a forest relict of Pinus pseudostrobus var. coatepecensis

Baeza-Guzmán Y, Camargo-Ricalde SL, Trejo Aguilar D, Montaño NM — 2023-11-09

Baeza-Guzmán Y, Camargo-Ricalde SL, Trejo Aguilar D, Montaño NM

FUNGAL AND BACTERIAL COMMUNITIES IN A FOREST RELICT OF PINUS PSEUDOSTROBUS VAR. COATEPECENSIS

Abstract: Mexico is a center of diversity for the genus Pinus, with 44% of pine species being endemic to the country. Mexican pine forests are recognized as hotspots for ectomycorrhizal fungi and bacteria due to the extensive interactions that take place between microorganisms and plants in their roots. These microorganisms play a vital role in the survival of pine species. This study aims to identify fungal and bacterial communities in a relict Mexican pine forest and evaluate the influence of soil physicochemical parameters on microbial composition. Sampling was conducted along a 145 m transect in an isolated natural relict of P. pseudostrobus var. coatepecensis, which is located within a commercial plantation of Pinus patula. A total of 18 soil samples were collected at predetermined distances along the transect, with replicated sampling points as follows: six samples at 20 cm intervals, four samples at 1 m intervals, four samples at 10 m intervals, and four samples at 25 m intervals. The results indicate that fungal composition varies even at short distances and is influenced by the C:N ratio, total carbon (C), total phosphorus (P), and total hydrogen ion concentration (H+). Ectomycorrhizal fungi (EcM) exhibited a higher relative abundance compared to saprotrophic and pathogenic fungi. A total of 69 EcM ASVs (Amplicon Sequence Variants) were identified, being the dominant genera Tomentella, Clavulina, Suillus, Russula, and Elaphomyces. Bacterial communities did not show significant variation in relation to the distance from the sampling points, but soil pH was identified as the main factor of bacterial composition. Dominant bacterial genera included Burkholderia, Bryobacter, Acidobacterium, and Acidothermus. Additionally, it was observed that current soil conditions influenced β diversity. Overall, the results demonstrate that soil fungal and bacterial communities associated with P. pseudostrobus exhibit a unique composition compared to other natural forest systems in the Neotropics.

Keywords: Bacteria, Diversity, Soil, Ectomycorrhizal Fungi, Pinus, Plantation

iForest 16 (6): 299-306 (2023) - doi: 10.3832/ifor4284-016
https://iforest.sisef.org/contents/?id=ifor4284-016

Research Articles: Effect of cadmium (Cd) and lead (Pb) soil contamination on the development of Hymenoscyphus fraxineus on Fraxinus excelsior and F. angustifolia seedlings

Vemić A, Popović V, Miletić Z, Radulović Z, Rakonjac L, Lučić A — 2023-11-09

Vemić A, Popović V, Miletić Z, Radulović Z, Rakonjac L, Lučić A

EFFECT OF CADMIUM (CD) AND LEAD (PB) SOIL CONTAMINATION ON THE DEVELOPMENT OF HYMENOSCYPHUS FRAXINEUS ON FRAXINUS EXCELSIOR AND F. ANGUSTIFOLIA SEEDLINGS

Abstract: In light of the increase of environmental pollution, we tested the effect of cadmium (Cd) and lead (Pb) soil contamination on ash dieback. The experiment included the inoculation of Hymenoscyphus fraxineus on Fraxinus excelsior and Fraxinus angustifolia seedlings growing on unpolluted soil, soil contaminated with cadmium (Cd), and soil contaminated with lead (Pb). At the end of the experiment, 173 days after soil contamination and 50 days since inoculation, all F. excelsior and F. angustifolia seedlings inoculated with H. fraxineus showed ash dieback symptoms in comparison to their control groups. However, both F. excelsior and F. angustifolia seedlings grown on contaminated soil had significantly increased necrotic lesions in comparison to the seedlings grown on uncontaminated soil. Our results showed for the first time that cadmium (Cd) and lead (Pb) soil contamination can significantly contribute to ash dieback and increase damage to F. excelsior and F. angustifolia seedlings.

Keywords: Soil Contamination, Cadmium (Cd), Lead (Pb), Hymenoscyphus fraxineus, Fraxinus excelsior, Fraxinus angustifolia

iForest 16 (6): 307-313 (2023) - doi: 10.3832/ifor4322-016
https://iforest.sisef.org/contents/?id=ifor4322-016

Research Articles: Is it needed to integrate mixture degree in Stand Density Management Diagram (SDMD)?

Askarieh A, Ruano I, Bravo F — 2023-10-28

Askarieh A, Ruano I, Bravo F

IS IT NEEDED TO INTEGRATE MIXTURE DEGREE IN STAND DENSITY MANAGEMENT DIAGRAM (SDMD)?

Abstract: Stand density management diagrams (SDMDs) are robust decision-support tools available to forest managers under limited information. SDMDs which are based on empirical models at stand level, graphically represent the temporal relationships among stand density, and different stand variables such as quadratic mean diameter, dominant height, and mean tree volume. They are used to define initial planting spacing or thinning interventions, to meet various management objectives. Nowadays, there is a growing interest in mixed-species forests as an option for adaptive forest management, where they are considered a guarantor to safeguarding a wide variety of ecosystem services within the framework of sustainability. But there is still a lack of knowledge and efficient tools and models for mixed stands such as SDMDs. This study aims to develop an SDMD for Pinus sylvestris L. and Pinus pinaster Ait. mixed stands in the Sierra de la Demanda (Spain) using data from the third Spanish National Forest Inventory. Both species are two of the most important conifers in Europe and the western Mediterranean basin. Different variables can be used to develop an SDMD. In this case, quadratic mean diameter, dominant height, total stand volume, number of trees per hectare, and stand density index were used. These equations were fit by simultaneous fitting including a new variable representing the proportion of both species in the mixed stand. The results of the simultaneous fitting showed the new variable representing the proportion of both species was not significant. Based on that, the SDMD was constructed without including mixture degree. This SDMD can be used by forest managers as an efficient tool to plan thinning operations.

Keywords: Reineke Index, Dominant Height, Silviculture, Thinning, Pinus sylvestris L, Pinus pinaster Ait.

iForest 16 (5): 274-281 (2023) - doi: 10.3832/ifor4005-016
https://iforest.sisef.org/contents/?id=ifor4005-016

Research Articles: Use of unmanned aerial vehicles for the diagnosis of parasitic plant infestation at the crown level in Pinus hartwegii

León-Bañuelos LA, Endara-Agramont AR, Nava-Bernal EG, Gómez-Demetrio W — 2023-10-28

León-Bañuelos LA, Endara-Agramont AR, Nava-Bernal EG, Gómez-Demetrio W

USE OF UNMANNED AERIAL VEHICLES FOR THE DIAGNOSIS OF PARASITIC PLANT INFESTATION AT THE CROWN LEVEL IN PINUS HARTWEGII

Abstract: Forest degradation has increased in recent years due to biotic, abiotic, and anthropogenic factors. Parasitic plants are some of the main disturbance agents affecting forest resources. In temperate forests, the most frequent pest such as parasitic plants are from the genus Loranthaceae spp. Monitoring parasitic plants through traditional methods requires a large amount of time and human resources. Unmanned aerial vehicles (UAV) as a remote sensing tool have increased in popularity in different regions. UAV were used to assess the degree of infestation of Yellow Dwarf Mistletoe (YDM). In the present study, the presence of Yellow Dwarf Mistletoe (Arceuthobium globosum Hawksw. & Wiens) was identified using two information collection methods to estimate the level of infestation in a Pinus hartwegii Lindl. forest. First, the traditional method (Hawksworth) was used to estimate the degree of infestation per individual tree. Second, a remote sensing method using UAV was used to capture information at the crown level. Then, the Colorimetric Ranges at the Pixel Level (CRPL) method was used in conjunction with the decomposition of pixels with the RGB (Red-Green-Blue) model to define areas with the presence of infestation. The result of the methods was compared by calculating the pixels equivalence percentages identified as infested per level of infestation. The Hawksworth’s method was used by determining three levels: level 0 (healthy) = 0-2% pixels; Level 1 (medium) = 3-5% pixels; and Level 2 (high) ≥ 5% pixels. The methods coincided in detecting a high level of infestation while were biased in detecting healthy trees and low levels of infestation. Nonetheless, the remote sensing method using UAV remains a viable alternative in the monitoring of mistletoe for its capacity to present an overall diagnosis of the level of infestation.

Keywords: Pattern Recognition, CRPL Algorithm, Arceuthobium globosum, Remote Sensing

iForest 16 (5): 282-289 (2023) - doi: 10.3832/ifor4002-016
https://iforest.sisef.org/contents/?id=ifor4002-016

Review Papers: Breeding and improvement of black locust (Robinia pseudoacacia L.) with a special focus on Hungary: a review

Ábri T, Cseke K, Keserü Z, Porcsin A, Szabó FM, Rédei K — 2023-10-28

Ábri T, Cseke K, Keserü Z, Porcsin A, Szabó FM, Rédei K

BREEDING AND IMPROVEMENT OF BLACK LOCUST (ROBINIA PSEUDOACACIA L.) WITH A SPECIAL FOCUS ON HUNGARY: A REVIEW

Abstract: Black locust (Robinia pseudoacacia L.) is a multipurpose tree species native to North America commonly planted worldwide for its resistant and durable wood, rapid growth, site tolerance, honey production, and other qualities. However, caution is warranted when planting the species outside its native range due to its potential invasiveness with respect to the native flora. Many countries, particularly Hungary and China, have been conducting forestry research on black locust for decades to increase black locust yields, nectar production, and stem quality. The main breeding objectives, such as fast growth, superior trunk quality or higher nectar production, have already been achieved. Existing reviews on this tree species do not cover the whole research history of breeding, making a comprehensive review increasingly critical to identify research gaps, trends, and drawbacks. The present study offers a systematic analysis of nearly 100 papers spanning the last century and the most recent research on black locust improvement. This study also includes a detailed summary of the available cultivars and clone selections worldwide.

Keywords: Tree Improvement, Selected Cultivars, Wood Production, Apiculture

iForest 16 (5): 290-298 (2023) - doi: 10.3832/ifor4254-016
https://iforest.sisef.org/contents/?id=ifor4254-016

Research Articles: Use of fallen dead trees by Japanese squirrels within cedar plantations in northeastern Japan

Honda S, Saito MU — 2023-10-19

Honda S, Saito MU

USE OF FALLEN DEAD TREES BY JAPANESE SQUIRRELS WITHIN CEDAR PLANTATIONS IN NORTHEASTERN JAPAN

Abstract: Deadwood in forests plays a critical role in maintaining the ecological functions. Small mammals use deadwood, and thus deadwood can mitigate the negative impacts of plantation on small mammals. This study focused on fallen dead trees in planted forests, and aimed to verify whether fallen dead trees affect behavioral patterns of Japanese squirrels. To clarify the use of fallen dead trees by Japanese squirrels in a Japanese cedar plantation, we observed squirrel behavior by camera trap surveys at 61 survey sites. Our findings showed that fallen dead trees play a crucial role in the behavior of Japanese squirrels, serving as landmarks for movement, vigilance, resting, and hoarding sites. These functions are critical for the survival of Japanese squirrels, suggesting that fallen dead trees in planted forests have positive impacts on their microenvironment use. The increase of deadwood due to disturbances such as heavy rainfall and snowfall resulting from climate change may provide benefits to arboreal small mammals in poorly managed planted forests. Additionally, leaving some of the deadwood generated during the harvesting process in properly managed forests can improve the quality of habitat for arboreal small mammals.

Keywords: Arboreal Small Mammal, Behavioral Ecology, Coarse Woody Debris, Forestry, Deadwood, Sciurus lis

iForest 16 (5): 262-267 (2023) - doi: 10.3832/ifor4338-016
https://iforest.sisef.org/contents/?id=ifor4338-016

Technical Advances: FIRE-RES Geo-Catch: a mobile application to support reliable fuel mapping at a pan-European scale

2023-10-19

Kutchartt E, González-Olabarria JR, Trasobares A, de-Miguel S, Cardil A, Botequim B, Vassilev V, Palaiologou P, Rogai M, Pirotti F

FIRE-RES GEO-CATCH: A MOBILE APPLICATION TO SUPPORT RELIABLE FUEL MAPPING AT A PAN-EUROPEAN SCALE

Abstract: We present a browser-based App for smartphones that is freely available to end-users for collecting geotagged and oriented photos depicting vegetation biomass and fuel characteristics. Our solution builds on advantages of smartphones, allowing their use as easy sensors to collect data by imaging forest ecosystems. The strength and innovation of the proposed solution is based on the following points: (i) using a low memory footprint App, streaming images and data with as little data-volume and memory as needed; (ii) using JavaScript APIs that can be launched from both a browser or as an installed App, as it applies features such as service workers and Progressive Web App; (iii) storing both image and survey data (geolocation and sensor orientation) internally to the device on an indexed database, and synchronizing the data to a cloud-based server when the smartphone is online and when all other safety tests have been successfully passed. The goal is to achieve properly positioned and oriented photos that can be used as training and testing data for future estimation of the surface fuel types based on automatic segmentation and classification via Machine Learning and Deep Learning.

Keywords: Mobile Data Collection, Citizen Science, Smartphone Position and Orientation, Wildfire, Image Analysis, Progressive Web Apps

iForest 16 (5): 268-273 (2023) - doi: 10.3832/ifor4376-016
https://iforest.sisef.org/contents/?id=ifor4376-016

Research Articles: A new zoning index for detecting areas of biological importance applied to a temperate forest in Central Mexico

2023-08-31

Torres-Díaz AN, González-Guillén MDJ, De Los Santos Posadas HM, Hernández De La Rosa P, León Merino A

A NEW ZONING INDEX FOR DETECTING AREAS OF BIOLOGICAL IMPORTANCE APPLIED TO A TEMPERATE FOREST IN CENTRAL MEXICO

Abstract: Biodiversity conservation is a priority because it is the cornerstone of ecosystem services and natural cycles, providing essential resources for the development of humans and other species. Several indices have been proposed to prioritize areas needing protection. However, some require specific information while others are based on subjective categorical variables, are limited to a particular plant community or cannot be represented at a spatial scale. We developed an Index of Importance for Biological Conservation (InICoB), which was applied to a temperate forest in central Mexico but can be used for any plant community by adjusting some of its parameters. The proposed index is objective, based on quantitative indicators of vegetation composition and structure, and can be spatially projected. InICoB was tested and validated on a temperate cloud forest (CF) and its associated communities: advanced secondary vegetation (ASV) / coffee plantations (CP), agriculture, and induced grasslands. Life forms, presence of endemic, climax, native and protected species, diversity, structural complexity, and complementarity were used as indicators in its construction. InICoB was calculated for 63 sampling units (SUs), and a geostatistical model was incorporated for its interpolation with environmental and social variables as predictors. The results show that InICoB adequately evaluated the different environmental units that cover the locality. Significant differences were observed between the forest and the secondary/induced vegetation. The highest value of InICoB (0.91) was found in the CF, and the lowest in induced vegetation (0.3). The geostatistical model showed that occupation of the land, distance to town, and slope have an important influence on InICoB. The advantages of InICoB include the use of quantitative indicators that can be applied to any plant community. Additionally, it is flexible with respect to the data collected, it can be calculated only with the presence/absence of species or it can include forest measurement data. Furthermore, it is easy to interpret and can be spatially represented in a raster layer that can be added to a geographic information system. Therefore, it can be a very helpful tool in decision-making for land use planning and evaluation of the effects of human activities on plant communities.

Keywords: Biodiversity Conservation, Composition and Structure, Plant Communities, Flora Indicators, Flora Diversity, Cloud Forest, Geostatistical Model

iForest 16 (4): 253-261 (2023) - doi: 10.3832/ifor4111-016
https://iforest.sisef.org/contents/?id=ifor4111-016

Research Articles: Scale dependency of the effects of landscape structure and stand age on species richness and aboveground biomass of tropical dry forests

2023-08-23

Reyes-Palomeque G, Dupuy JM, Portillo-Quintero CA, Andrade JL, Tun-Dzul FJ, Hernández-Stefanoni JL

SCALE DEPENDENCY OF THE EFFECTS OF LANDSCAPE STRUCTURE AND STAND AGE ON SPECIES RICHNESS AND ABOVEGROUND BIOMASS OF TROPICAL DRY FORESTS

Abstract: The structure and diversity of plant communities respond to changes in landscape structure and vary with spatial scale, stand age and plant size. Therefore, it is important to identify the scale (grain size and extent) at which secondary forest attributes of large and/or small plants and landscape structure are more closely associated. We performed multi-scale analyses in which different grain sizes and extents were assessed to determine the most appropriate spatial scale for assessing the association of large/small tree aboveground biomass and species richness with successional age and landscape structure using regression analysis. AGB and species richness were more strongly associated with landscape structure when large grain sizes (500 m2) were used, with R2 values between 0.31 and 0.43. Variation in AGB and species richness was explained primarily by successional age and landscape structure, respectively. At large extents, successional age was related to the AGB of large trees (R2 = 0.43); at intermediate extents, landscape structure was related to the species richness of large trees (R2 = 0.31). The approach and results of this study may facilitate the identification of appropriate areas and scales for the maintenance or restoration of tree diversity, carbon storage, and the provision of ecosystem services in tropical dry forests.

Keywords: Scale Effect, Grain, Spatial Extent, Multi-scale Analysis, Secondary Succession, Landscape Metrics.

iForest 16 (4): 234-242 (2023) - doi: 10.3832/ifor4239-016
https://iforest.sisef.org/contents/?id=ifor4239-016

Research Articles: Comparison of wood stack volume determination between manual, photo-optical, iPad-LiDAR and handheld-LiDAR based measurement methods

Purfürst T, De Miguel-Díez F, Berendt F, Engler B, Cremer T — 2023-08-23

Purfürst T, De Miguel-Díez F, Berendt F, Engler B, Cremer T

COMPARISON OF WOOD STACK VOLUME DETERMINATION BETWEEN MANUAL, PHOTO-OPTICAL, IPAD-LIDAR AND HANDHELD-LIDAR BASED MEASUREMENT METHODS

Abstract: The measurement of roadside wood stacks in the forest still plays an important role in many forestry operations. Traditional manual measuring methods can be laborious, inaccurate and error-prone. Therefore, the issue is whether 2.5D or 3D optical remote sensing measuring methods provide more precise or detailed results and advantages in further data processing. This study examined and partly developed nine different manual, photo-optical, iPad®-LiDAR and handheld laser scanner-LiDAR-based wood stack measurement methods. Forty-seven wood stacks, ranging from 8.9 to 209.3 m3 (totalling approximately 2700 m3), were measured and compared using these nine methods. All the methods give volume estimations, and none can be seen to give the real or true wood stack gross volume. Surprisingly, the results varied significantly within and between the individual methods, with up to a 9% mean relative deviation. The relative deviation is strongly dependent on the size of the wood stack. The 3D measurement methods using iPad® RGB and LiDAR recorded lower timber volumes than the other methods, in contrast to the method based on samples taken with handheld laser scanner-LiDAR, which overestimated the volume. Generally, optical- and laser-based surveying techniques could be more widely applied in measuring wood stacks in the future. However, such automatic wood stack gross volume determination approaches still face some challenges, regarding accuracy in the case of the 2.5D methods and the lack of automatisation in the case of 3D methods. Consequently, further research is required in the near future.

Keywords: iPad LiDAR, Wood Stack Volume, 3D Volume, Photo-optical Measurement, Personal Laser Scanner, SLAM, RVR

iForest 16 (4): 243-252 (2023) - doi: 10.3832/ifor4153-016
https://iforest.sisef.org/contents/?id=ifor4153-016

Research Articles: Strong relationships between soil and vegetation in reference ecosystems of a riparian Atlantic rainforest in the upper Doce River watershed, southeastern Brazil

2023-08-17

Ramos L, Negreiros D, Ferreira BSS, Figueiredo JCG, Paiva DC, Oki Y, Justino WDS, Santos RMD, Aguilar R, Nunes YRF, Fernandes GW

STRONG RELATIONSHIPS BETWEEN SOIL AND VEGETATION IN REFERENCE ECOSYSTEMS OF A RIPARIAN ATLANTIC RAINFOREST IN THE UPPER DOCE RIVER WATERSHED, SOUTHEASTERN BRAZIL

Abstract: Habitat loss and fragmentation have been impacting ecosystem services essential for human survival. The Brazilian Atlantic rainforest, a biodiversity hotspot, has suffered from historical deforestation and, more recently, from an environmental disaster caused by the Fundão dam collapse that released ore tailings drastically affecting a large territory in the Doce River watershed. This work aims to assess the relationships between soil properties and vegetation in a reference ecosystem to provide guidelines for restoration projects in areas affected by the dam collapse. We conducted phytosociological (vegetation characteristic) and soil quality studies in three distinct natural sites and studied different vegetation strata to better understand plant species composition in reference sites along the impacted Doce River and their potential role in community structuring and functioning. We recorded 140 species, 78 in the tree stratum, and 90 in the sapling stratum. Furthermore, our results highlight the influence of soil on floristic composition in the Atlantic rainforest. Small-scale edaphic variation influenced species composition in both sapling and tree strata. We also identified species of the same genus with strong association with the extremes of the edaphic gradient. Therefore, we highlight that studies in various regions along the Doce River watershed are of utmost importance to evaluate the association between species and soils. The particularities of the species are crucial to the effectiveness of restoration processes since this plant-soil correlation should not be extrapolated even within the same genus. This knowledge is of strategic relevance to provide scientific-based guidance for restoring these environments, aiming at the recovery of biodiversity and ecosystem services.

Keywords: Dam Breach, Fundão Dam Collapse, Reference Ecosystem, Restoration Ecology, Soil-vegetation Relationships

iForest 16 (4): 226-233 (2023) - doi: 10.3832/ifor4313-016
https://iforest.sisef.org/contents/?id=ifor4313-016

Research Articles: Evaluation of operating cost management models for selection cutting in Scandinavian continuous cover forestry

Bianchi S, Ahtikoski A, Muhonen T, Holmström E, Valkonen S, Nuutinen Y — 2023-08-12

Bianchi S, Ahtikoski A, Muhonen T, Holmström E, Valkonen S, Nuutinen Y

EVALUATION OF OPERATING COST MANAGEMENT MODELS FOR SELECTION CUTTING IN SCANDINAVIAN CONTINUOUS COVER FORESTRY

Abstract: The importance of continuous cover forestry (CCF) is increasing, yet there is lack of data and understanding about many aspects of this management, including the operational costs. Our objectives were to retrieve available harvesting cost models from published studies on selection cutting in Norway-spruce-dominated stands in Scandinavian countries and to evaluate them against real case studies. First, we retrieved three recently published harvesting cost models which provided explicit cost functions. Models 1 and 2, based on rotation forestry (RF) data and adapted for CCF, had separate sub-models for cutting and hauling costs. Model 3 was based on CCF data and produced total harvesting costs, including the cutting and hauling costs combined. Second, we measured cutting costs for 29 harvesting operations on stands with different stages of CCF structure. We then compared the observations with the simulations of Models 1 and 2 cutting cost sub-models for those cases. Third, we expanded the dataset, including a further 34 harvesting operations in stands with more advanced CCF structures (without measured costs). We then simulated the total harvesting costs for all three models in this dataset to investigate their general behaviour. On average, Models 1 and 2 cutting cost sub-models had relatively good and consistent predictions compared with the observed values. However, they differed in total costs due to different estimates for the hauling cost sub-models. Model 3 had predictions comparable to Models 1 and 2 in the more advanced stages of CCF, but much higher in the less advanced. This study provides important data regarding cutting costs in CCF and demonstrates the feasibility of using existing harvesting cost models.

Keywords: Harvesting systems, Finland, Cutting costs, Norway spruce

iForest 16 (4): 218-225 (2023) - doi: 10.3832/ifor4204-016
https://iforest.sisef.org/contents/?id=ifor4204-016

Research Articles: The effect of soil conditions on submountain site suitability for Norway spruce (Picea abies Karst.) in Central Europe

Samec P, Volánek J, Holík L, Rychtecká P, Balková M, Vranová V — 2023-07-31

Samec P, Volánek J, Holík L, Rychtecká P, Balková M, Vranová V

THE EFFECT OF SOIL CONDITIONS ON SUBMOUNTAIN SITE SUITABILITY FOR NORWAY SPRUCE (PICEA ABIES KARST.) IN CENTRAL EUROPE

Abstract: Norway spruce (Picea abies [L.] Karst.) occurred rarely at submountain altitudes before reaching its present position as the most important economic tree species in Central Europe. Spruce cultivation outside of natural sites is under constant threat from harmful agents. In this study, we focused on the indication of potentially suitable planting sites for Norway spruce in areas of protected submountain (< 700 m a.s.l) populations using linear discriminant analysis (LDA) of soil properties in oak-beech, mixed and spruce stands in the territory of the Czech Republic. The soil A-horizon properties in mixed stands were more similar to those in spruce than in broadleaved stands; stand mixtures resulted in lower soil property separability than the localization of individual populations (57% and 85%, respectively). The suitable sites were defined by acid phosphomonoesterase > 151 µg hour-1, soil porosity > 63%, aeration > 53%, bulk density < 0.86 g cm-3, cation exchange capacity < 18 cmol+ kg-1, Corg< 9% and Ntot< 0.5% in clusters comprising the Bohemian highlands, North Bohemian rock cities and the Outer Western Carpathians. The LDA of soil properties offered a useful tool for assessing both naturalness and forest threats to support sustainable management.

Keywords: Site Series, Spruce Cultivation, Soil Organic Matter, Extracellular Enzyme Activity

iForest 16 (4): 210-217 (2023) - doi: 10.3832/ifor4262-016
https://iforest.sisef.org/contents/?id=ifor4262-016

Research Articles: Wood production and nutritional status of Pinus taeda L. in response to fertilization and liming: a meta-analysis of the Americas

Rodrigues VDS, Motta ACV, Barbosa JZ, Ercole TM, Prior SA — 2023-07-25

Rodrigues VDS, Motta ACV, Barbosa JZ, Ercole TM, Prior SA

WOOD PRODUCTION AND NUTRITIONAL STATUS OF PINUS TAEDA L. IN RESPONSE TO FERTILIZATION AND LIMING: A META-ANALYSIS OF THE AMERICAS

Abstract: Loblolly pine (Pinus taeda L.) is one of the most planted forest species in the Americas. Since few studies have comprehensively assessed loblolly pine responses to fertilization, the present study performed a meta-analysis of the Americas based on 44 publications (1970-2022) of loblolly pine fertilization under field conditions. In general, fertilization increased root dry matter (+33%), litter (+21%), plant height (+6%), trunk diameter (+9%), wood yield (+30%), and needle concentrations of P (+9%), K (+36%), Ca (+17%), Mg (+14%), and S (+12%). Wood production was higher with residue fertilization, primarily with use of composite residues (cellulosic sludge + ash), compared to mineral fertilization. In regards to mineral applications, wood production was higher when multiple nutrients were added from fertilization and liming operations. Applications at planting (< 1 year) or on established trees (2-8 years), showed similar increases in wood production with higher responses occurring on sandy soils. These factors generally increased needle nutrient concentrations, except for no alteration or slight decreases in N under most conditions. The present study revealed loblolly pine responses to contrasting application strategies, which can help identify efficient fertility management practices for this commercially significant tree species.

Keywords: Loblolly Pine, Planted Forest, Waste, Sandy Soil, Needle Composition

iForest 16 (4): 195-201 (2023) - doi: 10.3832/ifor4296-016
https://iforest.sisef.org/contents/?id=ifor4296-016

Research Articles: Effective woody biomass estimation in poplar short-rotation coppices - Populus nigra × P. maximowiczii

Šrámek M, Weger J, Bubeník J, Matoušková M, Lengálová K, Matula R — 2023-07-25

Šrámek M, Weger J, Bubeník J, Matoušková M, Lengálová K, Matula R

EFFECTIVE WOODY BIOMASS ESTIMATION IN POPLAR SHORT-ROTATION COPPICES - POPULUS NIGRA × P. MAXIMOWICZII

Abstract: Knowledge of the quantity of woody biomass of poplar short-rotation coppice (SRC) on agricultural land is a basic tool for management decisions like rotation length, volume production and the financial balance sheet of economic activities. The expansion of SRC requires a fast, reliable, easily applicable and cheap method for estimating the biomass yield, but existing methods are based on labour-demanding and lengthy measurements of all shoots per tree. The objective of this study was to verify a novel rapid biomass estimation method that uses averaged attributes of only a few largest shoots as a predictor variable for woody biomass in a poplar SRC, hybrid clone J-105 (Populus nigra × P. maximowiczii). Using data from 39 sample stumps with 187 shoots in total, we modelled shoot biomass as a function of an increasing number of shoots in interaction with different shoot parameters at two poplar SRC plantations. Results showed that the DBH of only three of the largest shoots per stump proved to be accurate estimators of the total shoot biomass of the individual stump. Comparison of biomass estimates at the stand level with a real amount of biomass indicated differences between 6-14%, depending on the site.

Keywords: Poplar Hybrid Clone J-105, SRC, Allometric Equations, Biomass Estimation

iForest 16 (4): 202-209 (2023) - doi: 10.3832/ifor4200-016
https://iforest.sisef.org/contents/?id=ifor4200-016

Research Articles: Response to climate and influence of ocean-atmosphere phenomena on annual radial increments of Pinus oocarpa Schiede ex Schltdl. & Cham in the Lagunas de Montebello National Park, Chiapas, Mexico

2023-06-30

Ponce-Calderón LP, Villanueva-Díaz J, Rodríguez-Trejo DA, Bilbao BA, Álvarez-Gordillo GDC

RESPONSE TO CLIMATE AND INFLUENCE OF OCEAN-ATMOSPHERE PHENOMENA ON ANNUAL RADIAL INCREMENTS OF PINUS OOCARPA SCHIEDE EX SCHLTDL. & CHAM IN THE LAGUNAS DE MONTEBELLO NATIONAL PARK, CHIAPAS, MEXICO

Abstract: The Lagunas de Montebello National Park, Chiapas, Mexico, is one of the most important protected areas in terms of ecology and the provision of ecosystem services in the state of Chiapas; however, it lacks long-term climate information to support comprehensive plans for the conservation of endangered species and ecosystem restoration actions. The objectives of this work were to analyze: (i) the interannual variability of the annual rings of Pinus oocarpa Schiede in the Lagunas de Montebello National Park, as influenced by climate; and (ii) the ocean-atmosphere phenomena influence on both the interannual variability of the total ring-width series. A dendrochronological series of P. oocarpa was built for the period 1857-2018 (162 years), which indicates the presence of extreme hydroclimatic events in the region. Of these, the 1998 drought was a milestone for the management of this natural area due to the high-intensity fires that affected the area and caused unprecedented ecological, social, and economic damage in the site history. The climatic variables with the greatest influence on the annual radial increase of the species are precipitation and maximum temperature in winter-spring, when growth is positively associated with precipitation and negatively associated with temperature, attributed to increases in evapotranspiration. El Niño Southern Oscillation was the phenomenon with the highest correlation with climatic variability and the radial growth of the species, in frequencies of less than five years, although the positive influence of the Atlantic Multidecadal Oscillation was also assessed annually. Global warming, characterized by increasing temperature, threatens the persistence of plant communities in the study area; therefore, knowing its impact on the growth of species of economic importance is essential to support conservation actions.

Keywords: Dendrochronology, Hydroclimatic Variability, Drought, Pinus oocarpa

iForest 16 (3): 174-181 (2023) - doi: 10.3832/ifor4112-016
https://iforest.sisef.org/contents/?id=ifor4112-016

Research Articles: Identification of the ambrosia beetle Anisandrus dispar (Fabricius) (Coleoptera Curculionidae Scolytinae) using TaqMan™ probe assay on biological samples

2023-06-30

Rizzo D, D’Agostino A, Stabile I, Ranaldi C, Marrucci A, Zubieta CG, Da Lio D, Bartolini L, Pennacchio F, Rossi E, Garonna AP

IDENTIFICATION OF THE AMBROSIA BEETLE ANISANDRUS DISPAR (FABRICIUS) (COLEOPTERA CURCULIONIDAE SCOLYTINAE) USING TAQMAN™ PROBE ASSAY ON BIOLOGICAL SAMPLES

Abstract: The European shot-hole borer Anisandrus dispar (Fabricius) (Coleoptera Curculionidae Scolytinae) is a well-known ambrosia beetle living on shrubs and several ornamental and fruiting trees where it can cause heavy damages. Like other harmful xyleborine species, A. dispar can represent a potential threat outside its native region. Molecular diagnostic tools can lead to accurate identification of xylophagous species hidden in wooden matrix in phytosanitary surveys at entry points. A molecular assay based on qPCR TaqMan™ Probes was developed for the identification of A. dispar from different matrices. To setup and perform the test, DNA extraction was carried out from adults, larvae, and artificial samples of wood chips from oak healthy plants whose lysates were contaminated with a known amount of DNA of A. dispar adults. The assay has proven inclusive for A. dispar, and exclusive towards the non-target organisms, showing 100% analytical specificity. The limit of detection was 0.32 pg µL-1 for the samples of insect adult DNA of A. dispar, and at 0.8 pg µL-1 for the samples containing lysates of Quercus spp. and 0.1 ng µL-1 of A. dispar adult DNA. Repeatability and reproducibility showed low values independently from the matrix used for DNA extraction, confirming the possible use in diagnostics of biological samples even if not directly related to the presence of A. dispar developmental stages. The presented approach may be adjusted and applied for phytosanitary purposes to other quarantine pests and rapidly detect possible infestations in vegetal matrices globally traded.

Keywords: European Shot-hole Borer, Xyleborini, Quarantine Species, Molecular Diagnostics, Biological Traces

iForest 16 (3): 182-187 (2023) - doi: 10.3832/ifor4287-016
https://iforest.sisef.org/contents/?id=ifor4287-016

Research Articles: Climate-wise models of biomass productivity for hybrid poplar clones in Europe

Bianchi S, Lee D, Bergante S, Facciotto G, Hynynen J, Nervo G — 2023-06-30

Bianchi S, Lee D, Bergante S, Facciotto G, Hynynen J, Nervo G

CLIMATE-WISE MODELS OF BIOMASS PRODUCTIVITY FOR HYBRID POPLAR CLONES IN EUROPE

Abstract: Renewable bioenergy has the potential to contribute sustainably to the energy sector. Forestry is the main source of biomass for energy in Europe, and poplar (genus Populus) is widely used for short rotation coppice (SRC). Many studies have assessed poplar clones’ productivity but there is a lack of regional studies and links with the climate. We investigated the biomass productivity of twenty hybrid poplar clones for SRC. Clones were planted in sixteen locations across nine countries in Europe, although not all clones were replicated in all locations. In each location, clones were planted in three replicated plots. All plots were harvested after four years, and the aboveground dry biomass estimated. We fitted clone-specific linear mixed models of total aboveground dry biomass production at plot level as function of climatic variables. For many clones (eight) only annual heat moisture deficit negatively affected productivity, in few cases (3) together with a quadratic term for a smoother relationship. In some other clones (five) only the mean summer precipitation positively and linearly affected productivity. On average, the variance explained by the fixed effects in those models was 56%. For the remaining clones (seven), no climate variables resulted significant. Our study explicitly investigated the quantitative link between water availability and poplar SRC productivity, one of the most important known factors but not often studied with a modelling approach. Further, we show the most productive clones in dried conditions. We also highlight the need to larger scale regional experiments to produce models that can be used in climate change scenarios.

Keywords: Hybrid Poplar, Short Rotation Coppice, Aridity Index, Water Availability, Above Ground Biomass

iForest 16 (3): 188-194 (2023) - doi: 10.3832/ifor4211-016
https://iforest.sisef.org/contents/?id=ifor4211-016

Research Articles: Exposure elevation and forest structure predict the abundance of saproxylic beetles’ communities in mountain managed beech forests

2023-06-08

Parisi F, Mazziotta A, Vangi E, Tognetti R, Travaglini D, Marchetti M, D’Amico G, Francini S, Borghi C, Chirici G

EXPOSURE ELEVATION AND FOREST STRUCTURE PREDICT THE ABUNDANCE OF SAPROXYLIC BEETLES’ COMMUNITIES IN MOUNTAIN MANAGED BEECH FORESTS

Abstract: In the managed beech forests of Central Italy (Molise), the diversity of saproxylic species is potentially under threat by intensive management. To evaluate the impact of forestry on the biodiversity of these ecosystems, we analyzed the relationship between abundance of saproxylic beetles and (i) forest stand exposure and elevation, (ii) deadwood availability (coarse woody debris - CWD - and stumps), (iii) abundance of microhabitats. Four sampling sectors with different altitudes and exposure were identified in a 400-ha study area in the Appenine mountains. Fifteen circular plots (13 m radius) were established in each sector where deadwood and microhabitats were surveyed and saproxylic beetles sampled. We fitted joint species distribution models to quantify the relationship between forest attributes and saproxylic species’ abundance, including the interactions with their family and trophic category. Overall, 2334 specimens belonging to 64 species of saproxylic beetles were collected. Both abundance and species richness were higher in the sectors with high elevation (respectively, 55% and 44%) and South exposure (respectively, 28% and 44%). Average deadwood volumes were low (stumps: 7.6 m3 ha-1; CWD: 0.3 m3 ha-1; snags: 0.4 m3 ha-1), and insect galleries were the most abundant microhabitat (380 records over a total of 434). The most important variables affecting abundance were stump characteristics (model deviance = 81.2), elevation (deviance = 64.7), and CWD characteristics (deviance = 58.0). Our results show that topographical variables and forest structure jointly affect the abundance patterns of saproxylic beetle communities in managed beech forests. These ecological interactions imply that management has different impacts on the saproxylic communities in different topographic conditions. To acknowledge this complexity we advocate for a landscape-level forest management supporting the local beetle diversity maintaining a mosaic of semi-natural forest characteristics in different topographic contexts. The ecological value of the forest landscape will be further enhanced by the application of closer-to-nature management interventions based on deadwood retention, microhabitat creation and tree retention, in line with the guidelines of the new EU Forest Strategy for 2030.

Keywords: Deadwood, Forest Heterogeneity, Fourth-corner Problem, Italy, Joint Species Distribution Models, Microhabitats, Trophic Categories

iForest 16 (3): 155-164 (2023) - doi: 10.3832/ifor4264-016
https://iforest.sisef.org/contents/?id=ifor4264-016

Research Articles: Fine root morphological traits and production in coniferous- and deciduous-tree forests with drained and naturally wet nutrient-rich organic soils in hemiboreal Latvia

Bardule A, Polmanis K, Krumšteds LL, Bardulis A, Lazdinš A — 2023-06-08

Bardule A, Polmanis K, Krumšteds LL, Bardulis A, Lazdinš A

FINE ROOT MORPHOLOGICAL TRAITS AND PRODUCTION IN CONIFEROUS- AND DECIDUOUS-TREE FORESTS WITH DRAINED AND NATURALLY WET NUTRIENT-RICH ORGANIC SOILS IN HEMIBOREAL LATVIA

Abstract: Fine root production is one of the key elements of carbon (C) turnover in soil in afforested peatlands and forest lands with organic soils. We estimated variability in fine root morphology traits and annual production in hemiboreal forests dominated by coniferous trees (Norway spruce) and deciduous trees (silver birch and black alder) with nutrient-rich organic soils in Latvia. In total, 23 research sites were established in drained and naturally wet forests of different ages, and ingrowth core techniques were used to sample fine roots and subsequently determine fine root morphology traits and annual production, and calculate C input through fine root litter. Significant differences in several fine root morphological traits between coniferous- and deciduous-trees-dominated stands were found. Fine root production tended to be higher in coniferous-trees-dominated stands and positively correlated with several forest stand characteristics: stand age, average tree diameter at breast height, basal area and average tree height, but negatively correlated with nitrogen and phosphorus content in soil. C input through fine root litter ranged up to 0.46 ± 0.16 t ha-1 yr-1. It is necessary to conduct further research, including multi-annual estimates in a wider set of forest stands with diverse dominant tree species and growing conditions, to improve estimates, patterns and understanding of C flows through fine root litter in drained and naturally wet organic soils.

Keywords: Fine Roots, Hemiboreal Forests, Drained Organic Soil, Naturally Wet Organic Soil, Fine Root Production, Morphology

iForest 16 (3): 165-173 (2023) - doi: 10.3832/ifor4186-016
https://iforest.sisef.org/contents/?id=ifor4186-016

Research Articles: A primary evaluation of Syrian forest damage since 2011: a case study of Alhamam and Alboz forest sites

2023-05-30

Aldakhil M, Abdullateef S, Mahmoud F, Alhasan A, Lakmes A, Al Abdullah M, Watmough GR

A PRIMARY EVALUATION OF SYRIAN FOREST DAMAGE SINCE 2011: A CASE STUDY OF ALHAMAM AND ALBOZ FOREST SITES

Abstract: Forests and trees make vital contributions to well-being, economic activities, ecosystem functioning and global system dynamics. There has been a lack of studies on the evaluation of the drivers of Syrian forest damage during the current conflict. This study estimated the damage since 2011 in the Alhamam and Alboz forest sites in Idlib province of Syria and evaluated the drivers of this damage. A multidimensional approach to damage assessment was developed which combined forest plot inventories, remotely sensed satellite image analysis, questionnaires and focus groups to enable a comparison of the forest from 2011 and 2017. The plot inventory data and remote sensing analysis provided estimates of forest damage and loss whilst focus groups and questionnaires provided vital information on the drivers of forest loss which is required for developing reforestation programmes. Overall, forest inventory data and satellite image analysis results indicated a reduction in tree cover, density and plant diversity. The results indicate a much higher loss of forest than is available from global products such as Global Forest Watch due to the prevalence in Syria of low-density Oak forests such as Alhamam not being classed as forest. The results of questionnaires and focus groups showed that the main cause of damage was an increased demand for fire-wood driven by a lack of fuel oil and increased unemployment, reduced household incomes and general price rises, making fuel more unaffordable. Respondents to surveys generally understood the importance of trees and forests and overtime the local knowledge of the importance of forest resources had not changed. This multidimensional approach indicates a reduced capacity of institutions to protect forests and will help to establish strategic plans to serve and protect the forest in the future.

Keywords: Global Forest Watch, Conflict, Deforestation, Syria

iForest 16 (3): 144-154 (2023) - doi: 10.3832/ifor4032-016
https://iforest.sisef.org/contents/?id=ifor4032-016

Research Articles: Evaluation of urban forest spatial distribution characteristics in Guangdong - Hong Kong - Macao Greater Bay Area

Zhao Q, Zhang C, Hu R, Qian W, Wei Y — 2023-05-16

Zhao Q, Zhang C, Hu R, Qian W, Wei Y

EVALUATION OF URBAN FOREST SPATIAL DISTRIBUTION CHARACTERISTICS IN GUANGDONG - HONG KONG - MACAO GREATER BAY AREA

Abstract: To understand the health and ecological benefits of scenic recreational forests, we elucidated their spatial distribution characteristics, which can be used to create guidelines and reveal strategic issues regarding the spatial distribution of tree species. We randomly set up 900 m2 quadrats in scenic recreational forest communities in Guangzhou, Foshan, and Zhuhai, and surveyed each tree using LiDAR. We then calculated the living vegetation volume (LVV) and amount of recreational space on the forest floor (RSFF), and analyzed the differences in spatial distribution characteristics across cities, locations, and forest types. The spatial distribution characteristics of trees differed between different cities, but were similar among different locations and forest types. Urban scenic recreational forest areas are thus configured based on aesthetics, recreational functions, and the spatial distribution characteristics of different tree species. Additionally, the relationship between the tree crown LVV and the RSFF was generally synergistic, yet contradictory. Although an increase in LVV can effectively improve ecological benefits, it may also reduce RSFF and other benefits provided by tree crowns to urban residents.

Keywords: Urban Forests, Living Vegetation Volume, Forest Floor Recreational Space, Spatial Distribution Strategy

iForest 16 (3): 136-143 (2023) - doi: 10.3832/ifor4268-016
https://iforest.sisef.org/contents/?id=ifor4268-016

Research Articles: Effects on soil physicochemical properties and seedling growth in mixed high forests caused by cable skidder traffic

Naghdi R, Tavankar F, Solgi A, Nikooy M, Marchi E, Picchio R — 2023-04-23

Naghdi R, Tavankar F, Solgi A, Nikooy M, Marchi E, Picchio R

EFFECTS ON SOIL PHYSICOCHEMICAL PROPERTIES AND SEEDLING GROWTH IN MIXED HIGH FORESTS CAUSED BY CABLE SKIDDER TRAFFIC

Abstract: The use of wheel skidders for timber extraction from tree stump to roadside landing has become more and more widespread. Although the use of wheel skidders has the advantages of high production and reduced extraction costs, it also damages the soil and impedes forest regeneration. The main purpose of this study was to investigate the effect of machine traffic using the Timberjack 450C (two, six and 15 passes) on two slope classes (SC) of skid trails. A low slope is considered to be <20% and a high slope is at >20%. The effects on soil physicochemical properties and seedling growth (alder, Alnus subcordata C.A. Mey. and maple, Acer velutinum Boiss.) in natural mixed beech stands in the Hyrcanian forests in Northern Iran were observed and studied. The results showed that the different factors of traffic intensity (TI) and SC had a significant impact on soil physicochemical properties and subsequent seedling growth. After two machine passes in a low TI on both low and high slopes, soil bulk density (BD) increased by 49.3% and 59.2% and penetration resistance increased by 30.5% and 38.5%, while total porosity decreased by 19.5% and 23.5%. The forest floor decreased by 30.9% and 42%, organic carbon decreased by 25.6% and 39.4%, nitrogen decreased by 18.5% and 26.3%, phosphorus decreased by 14.1% and 23%, and potassium decreased by 10.7% and 24.2%, respectively as compared with the control area. Our results indicated additional BD increments after two, six and 15 machine passes of 49.3%, 17.9% and 8.3% in the low slope, respectively, and 59.2%, 16.5% and 7.1% in the high slope, respectively. The mean of the germination rate (GR) of alder and maple seedlings in the control area was 58.3% and 46.1%, respectively, while after two, six and 15 passes, the GR of alder seedlings reduced to 50%, 46.4% and 37.5%, respectively, while that of maple seedlings reduced to 36.1%, 28.6% and 25.6%, respectively. Additionally, after two machine passes, stem length, main root length, and total dry biomass decreased by 28.7%, 34.9% and 34% in alder seedlings, respectively, and 27.9%, 27.6% and 33.3% in maple seedlings, respectively. Comparison of the response of the two seedling species to soil compaction showed that although alder had a higher GR than maple, the root growth of maple was higher than that of alder.

Keywords: Forest Regeneration, Soil Compaction, Trail Gradient, Wheel Skidder

iForest 16 (2): 127-135 (2023) - doi: 10.3832/ifor4103-016
https://iforest.sisef.org/contents/?id=ifor4103-016

Research Articles: Spatial distribution of aboveground biomass stock in tropical dry forest in Brazil

2023-04-17

Viana Santos HK, Borges De Lima R, Figueiredo De Souza RL, Cardoso D, Moonlight PW, Teixeira Silva T, Pereira De Oliveira C, Alves Júnior FT, Veenendaal E, Paganucci De Queiroz L, Rodrigues PM, Dos Santos RM, Sarkinen T, De Paula A, Barreto-Garcia PAB, Pennington T, Phillips OL

SPATIAL DISTRIBUTION OF ABOVEGROUND BIOMASS STOCK IN TROPICAL DRY FOREST IN BRAZIL

Abstract: Climate change is being intensified by anthropogenic emission of greenhouse gasses, highlighting the value of forests for carbon dioxide storing carbon in their biomass. Seasonally dry tropical forests are a neglected, threatened, but potentially critical biome for helping mitigate climate change. In South America, knowing the amount and distribution of carbon in Caatinga seasonally dry vegetation is essential to understand its contribution to the global carbon cycle and subsequently design a strategic plan for its conservation. The present study aimed to model and map the spatial distribution of the potential forest biomass stock across 32 forest fragments of Caatinga, in the state of Bahia, Brazil, using regression kriging and Inverse Square of Distance techniques, building from point measurements of vegetation biomass made on-the-ground in ecological plots. First, a model for estimating biomass was fitted as a function of environmental variables to apply regression kriging, and then applied to the maps of the selected components. Elevation, temperature, and precipitation explained 46% of the biomass variations in the Caatinga. The model residuals showed strong spatial dependence and were mapped based on geostatistical criteria, selecting the spherical semivariogram model for interpolation by ordinary kriging. Biomass was also mapped by the Inverse Square of Distance approach. The quality of the regression model suggests that there is good potential for estimating biomass here from environmental variables. The regression kriging showed greater detail in the spatial distribution and revealed a spatial trend of increasing biomass from the north to south of the domain. Additional studies with greater sampling intensity and the use of other explanatory variables are suggested to improve the model, as well as to maximize the technique’s ability to capture the actual biomass behavior in this newly studied seasonally dry ecosystem.

Keywords: Geostatistics, Regression Kriging, Spatial Analysis, Forest Inventory

iForest 16 (2): 116-126 (2023) - doi: 10.3832/ifor4104-016
https://iforest.sisef.org/contents/?id=ifor4104-016

Research Articles: Ecological factors affecting the recent Picea abies decline in Slovenia: the importance of bedrock type and forest naturalness

Kermavnar J, Kutnar L, Pintar AM — 2023-03-29

Kermavnar J, Kutnar L, Pintar AM

ECOLOGICAL FACTORS AFFECTING THE RECENT PICEA ABIES DECLINE IN SLOVENIA: THE IMPORTANCE OF BEDROCK TYPE AND FOREST NATURALNESS

Abstract: Norway spruce (Picea abies [L.] Karst.) has been at the centre of controversy for many decades. Recent evidence of its profound disturbance-induced damage and consequent stock depletions across forest landscapes in Europe has reinforced doubts regarding the sustainability and prospects of this tree species in the future. Like many other European countries, Slovenia has experienced significant Norway spruce mortality and a decrease in growing stock primarily as the result of several disturbance agents (bark beetle outbreaks, an ice storm, windthrows). We investigated a countrywide spruce growing stock decline based on data between 2010 and 2018. Particular focus was placed on identifying the main ecological drivers of this decline, namely geological conditions, climatic parameters, soil attributes, topographic factors and forest stand characteristics. The effects of potential predictors on the relative change (%) in spruce volume (m3 ha-1) during the period 2010-2018 were analysed with Generalized Additive Models. Based on a national dataset including forest compartments (n = 6355) with a spruce growing stock decline > 10%, we found mixed support for ecology-based hypotheses. While spruce decline responded to bedrock type as predicted (i.e., greater relative decline in carbonate compared to silicate compartments), higher forest naturalness (preservation of tree species composition) was not associated with a lower decline. Spruce decline was amplified by higher potential evapotranspiration and soil clay content but showed a strong negative relationship with spruce proportion in the year 2010. General trends along the gradients of other selected predictors (stoniness/rockiness and heat load index) were less pronounced. The results suggest that most of these ecological predictors interact with geology and forest naturalness in affecting Norway spruce decline. Our analysis reveals that bedrock type can play an important role due to its mitigating effects. However, forest naturalness is of secondary significance as intensified large-scale forest disturbances likely override its buffering potential.

Keywords: Norway Spruce, Bark Beetle Outbreaks, Ice Storm, Soil-geology Relationship, Tree Species Composition, Slovenia

iForest 16 (2): 105-115 (2023) - doi: 10.3832/ifor4168-016
https://iforest.sisef.org/contents/?id=ifor4168-016

Research Articles: Amazon forest biomass: intra- and interspecific variability in wood density drive divergences in Brazil’s far north

2023-03-21

Farias HLS, Pequeno PACL, Silva WR, Melo VF, Carvalho LCDS, Perdiz RDO, Citó AC, Fearnside PM, Barbosa RI

AMAZON FOREST BIOMASS: INTRA- AND INTERSPECIFIC VARIABILITY IN WOOD DENSITY DRIVE DIVERGENCES IN BRAZIL’S FAR NORTH

Abstract: Wood density (WD) is an important functional trait of tree species. Understanding spatial WD variability as a function of environmental determinants improves our ability to estimate carbon stocks in the woody biomass of tropical forests. However, the role of each environmental variable affecting the intra- and interspecific variability of WD is not entirely clear for most forest ecosystems. In Amazonia there are recurrent uncertainties in estimates of regional woody biomass. The aim of the study was to investigate the effects of environmental conditions on the intra- and interspecific variability of WD for tree assemblages in forests of the northern Brazilian Amazon. A single sample was extracted from each of 680 individuals (108 species, 82 genera, 38 families; stem diameter ≥10 cm) dispersed among 129 plots distributed along a hydro-edaphic gradient. General community-averaged WD (0.703 ± 0.133 g cm-3; range: 0.203 to 1.102 g cm-3) was high in relation to other Amazonian areas because 62% of the species and 69% of the sampled individuals had high WD values (>0.650 g cm-3). Altitude (a proxy for drainage), clay and soil micronutrient content explained 23% of the spatial variation in WD. Partitioning WD variation into species-substitution (turnover) and intraspecific-variation components slightly increased the explanatory power to 26%. The analysis of interspecific variability showed that forests occurring in seasonally flooded areas are characterized by tree assemblages with species tolerant to P-poor soils, where mean WD (0.742 g cm-3) is about 4% higher than the mean (0.713 g cm-3) for tree assemblages on unflooded uplands where soils have less limitations from nutrient poverty. Our results represent an improvement in the estimates of biomass because they promote adjustments (1.4%-16.3%) to the previous estimates of woody biomass in the northern Brazilian Amazon forests considering different environmental conditions.

Keywords: Basic Density, Maracá, Roraima, Seasonal Forests, Wood Specific Gravity

iForest 16 (2): 95-104 (2023) - doi: 10.3832/ifor4137-016
https://iforest.sisef.org/contents/?id=ifor4137-016

Research Articles: Factors of soil CO2 emission in boreal forests: evidence from Central Siberia

Makhnykina AV, Tychkov II, Prokushkin AS, Pyzhev AI, Vaganov EA — 2023-03-19

Makhnykina AV, Tychkov II, Prokushkin AS, Pyzhev AI, Vaganov EA

FACTORS OF SOIL CO2 EMISSION IN BOREAL FORESTS: EVIDENCE FROM CENTRAL SIBERIA

Abstract: Soils of boreal forests are crucial carbon reserves. The response of soil carbon emission to climate change significantly affects the concentration of carbon dioxide in the atmosphere. Soil carbon emission models frequently show a nonlinear response to temperature, but soil moisture is an important limiting factor, often overlooked in energy limited ecosystems. We suggest a statistical model of soil CO2 emission constrained by soil moisture and temperature for different ecosystems in the boreal zone. We tested this modelling strategy using direct measurements of seasonal soil CO2 emission near the research observatory ZOTTO near the Bor settlement, Central Siberia, Russia, in 2012-2017. Soil moisture explained a significant amount of variability of soil emission: the adjusted R2 was twice higher than in the baseline model. Although the temperature-only model describes the annual variability of carbon dioxide emissions quite well, the addition of moisture measurement significantly refines the quality of prediction of the seasonal component dynamics. Models including both temperature and soil moisture could serve as a promising tool to analyze the carbon cycle in boreal forest ecosystems.

Keywords: Boreal Forests, Soil CO2 Emission, Soil Temperature, Soil Moisture, Carbon Cycle, Climate Change, Exponential Model

iForest 16 (2): 86-94 (2023) - doi: 10.3832/ifor4097-016
https://iforest.sisef.org/contents/?id=ifor4097-016

Research Articles: The nurse-plant effect under the dislodgement stress of landslides

Yang JH, Chang LW, Hsu KC, Fan CC, Doley D, Song GZM — 2023-03-16

Yang JH, Chang LW, Hsu KC, Fan CC, Doley D, Song GZM

THE NURSE-PLANT EFFECT UNDER THE DISLODGEMENT STRESS OF LANDSLIDES

Abstract: While the mitigating effects of trees on shallow landslide occurrence are well recognised, the impact of landslides on tree community structure and tree-tree interactions have received much less research attention. The structures of tree communities before and after landslides were compared in a 25-ha subtropical forest plot. Tree-tree interactions were examined by analysing the pre- and post-landslide spatial point patterns of large (DBH ≥ 20 cm) and small (1 cm ≤ DBH < 20 cm) tree cohorts. In landslide scarps, 35 (34%) of 104 large trees and 467 (13%) of 3.072 small trees survived. Large (L) and small (S) tree cohorts were paired together for spatial analyses, including pre-landslide (PL) (LPL-SPL), surviving (S) (LS-SS), and missing (M) large-small tree paired cohorts (LM-SM). We randomly selected trees from the pre-landslide tree cohorts to create two virtual paired cohorts, the L34%-S13% and L66%-S87% paired cohorts, whose population sizes were identical to the field-observed LS-SS and LM-SM paired cohorts respectively, but with random spatial patterns. Post-landslide survival rates of trees increased monotonically with DBH. Large trees dislodged by landslides scarcely reduced small-tree survival. Evidence for this included: (i) the distance from small trees to the nearest large trees of the LM-SM paired cohort did not differ significantly from that of the virtual L66%-S87% paired cohort; (ii) survival rates of small trees near LM individuals did not differ significantly from those without large trees nearby. Surviving large trees had positive effects on the survival of small trees, indicated by: (i) the distance from small trees to the nearest large trees of the LS-SS paired cohort was significantly lower than that of the virtual L34%-S13% paired cohort; (ii) SS individuals clumped around LS individuals, whereas the virtual L34%-S13% spatial relationship was random. Large trees prevent landslide dislodgement of adjacent small trees through the nurse-plant effect. Our study suggests that landslide damage in sloping forests may be reduced simply by constantly maintaining a critical density of large trees.

Keywords: Facilitation, Forest Dynamics Plot, Nurse-plant Effect, Point Pattern Analysis, Slope Stability

iForest 16 (2): 78-85 (2023) - doi: 10.3832/ifor4017-015
https://iforest.sisef.org/contents/?id=ifor4017-015

Research Articles: Co-benefits of biomass and biodiversity in a protected mountain forest of West Java, Indonesia

Rozak AH, Kusuma YWC, Junaedi DI — 2023-03-05

Rozak AH, Kusuma YWC, Junaedi DI

CO-BENEFITS OF BIOMASS AND BIODIVERSITY IN A PROTECTED MOUNTAIN FOREST OF WEST JAVA, INDONESIA

Abstract: Tropical mountain forests are relatively less disturbed and store a large amount of carbon in tree biomass. A high level of species diversity compared to the boreal and temperate forests is also maintained and indicates a positive relationship with tree biomass on a small scale or at plot level. This study aimed to estimate above-ground biomass stocks (AGB) and disentangle the influence of forest structure and attributes on AGB in a small mountain forest. Forty 400 m² plots were randomly established in Takokak Nature Reserve (TNR), a 60-ha protected area at an elevation between 1150-1560 m a.s.l., located in West Java, Indonesia. All trees within the plot were identified, and their respective diameter at breast height (DBH) was measured. AGB was calculated using a global allometric model. Five independent variables, i.e., stem density, stem density of large trees (DBH >50 cm), community weighted mean wood density, rarefied species richness, and Fisher’s alpha index, were analysed using a linear model. Our results showed that AGB in TNR was comparable to other forest types in Indonesia and acted as carbon storage in the mountain regions. AGB in the TNR reached 486 Mg ha-1, of which 75% was contributed by large trees (DBH >50 cm). Three species, i.e., Liquidambar excelsa (Altingiaceae), Schima wallichii (Theaceae), and Lithocarpus sp. (Fagaceae), represent at least 70% of the total biomass in the study site. We also found that forest structures and traits, i.e., stem density, stem density of large trees, and community weighted mean wood density, drive AGB variations but not tree diversity indices. However, although diversity indices were not correlated to AGB, we found that TNR is home for endemic and threatened species on the IUCN Red List. Therefore, we suggest that the management strategies of the tropical forests should include both the conservation of the carbon stock and biodiversity.

Keywords: Carbon Balance, Climate Change, Climate Mitigation, Endemic Tree, Nature Reserve REDD+, Threatened Species

iForest 16 (2): 62-69 (2023) - doi: 10.3832/ifor4068-015
https://iforest.sisef.org/contents/?id=ifor4068-015

Review Papers: Carbon neutrality of forest biomass for bioenergy: a scoping review

Selivanov E, Cudlín P, Horáček P — 2023-03-05

Selivanov E, Cudlín P, Horáček P

CARBON NEUTRALITY OF FOREST BIOMASS FOR BIOENERGY: A SCOPING REVIEW

Abstract: The exploitation of forest biomass for bioenergy is commonly perceived as part of a broad strategy for climate change mitigation due to the view that forest biomass is carbon neutral. The aims of this study are to distinguish the most widely used definition of carbon neutrality and to identify the most frequently discussed aspects of the concept of carbon neutrality. This research is conducted in the form of a scoping review. The results of the scoping review demonstrated that there is no generally accepted definition of carbon neutrality. Eight main concepts of carbon neutrality were identified. The most frequently discussed aspects of the carbon neutrality concept were temporal and spatial boundaries, scenario-based assumptions, and the source of biomass feedstock. This research provides a comprehensive summary of the concept of carbon neutrality and contributes to the debate regarding forest biomass exploitation for bioenergy.

Keywords: Bioenergy, Biofuels, Carbon Cycle, Climate Change, Forest Residues, Life Cycle Assessment

iForest 16 (2): 70-77 (2023) - doi: 10.3832/ifor4160-015
https://iforest.sisef.org/contents/?id=ifor4160-015

Research Articles: Modelling natural regeneration of Oak in Saxony, Germany: identifying factors influencing the occurrence and density of regeneration

Axer M, Martens S, Schlicht R, Eisenhauer DR, Wagner S — 2023-02-16

Axer M, Martens S, Schlicht R, Eisenhauer DR, Wagner S

MODELLING NATURAL REGENERATION OF OAK IN SAXONY, GERMANY: IDENTIFYING FACTORS INFLUENCING THE OCCURRENCE AND DENSITY OF REGENERATION

Abstract: In the course of climate change, natural regeneration of oaks (Quercus spp.) is gaining in importance for forest conversion to climate-adapted mixed forests. In order to predict areas in which natural oak regeneration could establish, variables influencing the occurrence and density of oak regeneration were identified using geostatistical zero-altered negative binomial generalized linear models (ZANB). For this purpose, large-scale inventory data from the state forest of Saxony were analysed. The dataset was derived from 6060 permanent plots. The results show that the occurrence of oak regeneration depends on a number of environmental variables. In addition to seed availability, the establishment environment, especially with regard to the light ecology of oak regeneration, was important. High basal area of pine increased the probability for oak regeneration occurrence. The most important variables for the regeneration density of oak have similarly been found to be those describing the seed availability. The highest regeneration densities are predicted within oak stands, with an optimum relationship at 25 m2 ha-1 of oak basal area. The results further show that a high regeneration density was achieved on sites with low fertility and favourable light conditions. Oak regeneration density increased with increasing browsing percent on rowan, indicating that browsing on oak can be reduced if other palatable species are available. Using the identified variables, the occurrence and density of oak regeneration can be predicted in space with high accuracy. The statistical tool developed can be used for planning forest conversion incorporating natural regeneration.

Keywords: Oak, Established Natural Regeneration, INLA, Zero-altered Negative Binomial Model, Spatial Random Effects, Bayesian Inference

iForest 16 (1): 47-52 (2023) - doi: 10.3832/ifor4064-015
https://iforest.sisef.org/contents/?id=ifor4064-015

Research Articles: Fluctuation of the ecological niche of Moringa peregrina (Forssk.) Fiori with topoclimatic heterogeneity in southern Iran

Piri Sahragard H, Karami P, Ajorlo M — 2023-02-16

Piri Sahragard H, Karami P, Ajorlo M

FLUCTUATION OF THE ECOLOGICAL NICHE OF MORINGA PEREGRINA (FORSSK.) FIORI WITH TOPOCLIMATIC HETEROGENEITY IN SOUTHERN IRAN

Abstract: Heterogeneity can be studied for any dynamic or fixed environmental factors over time. However, determining the extent of heterogeneity occurrence in terms of habitat suitability, variability of dynamic and fixed factors, as well as landform role is an issue that has received less attention. This study aimed to investigate the distribution of Moringa peregrina at two climate change scenarios, to identify the Region of High Heterogenetic (ROHH) of the habitats in those scenarios and to ascertain the heterogeneity of habitat variables of the species in southern Iran. The current and potential distributions of the species in mild and severe climate change scenarios of 2050 and 2070, respectively, were modeled through the Ensemble technique using the climatic and topographic (topoclimatic) variables. The current distribution with four predictions of mild to severe Representative Concentration Pathways (RCP2.5, RCP4.5, RCP6.0 and RCP8.5) were entered into the principal component analysis (PCA) each year to achieve the heterogeneity of distribution. Then, the ROHH was calculated for areas with fluctuations of more than 50%. The topoclimatic variables in the ROHH were compared with the value of each variable in the current distribution in different landforms. The climatic variables of temperature seasonality and mean diurnal range had the greatest impact on M. peregrina distribution. There was more than 90% spatial agreement between the species current and potential distributions under different climate change scenarios (minimum Kappa = 0.9). In climate change scenarios, increase in species distribution is mainly limited by reduced rainfall, high temperature and altitude. The heterogeneity of habitat variables varied greatly in the ROHH and current presence points, indicating the species attempt to occupy new ecological niches. The highest distribution of the species was in the canyons and mountain tops, and the species seeks to occupy these areas in the ROHH. The magnitude of fluctuations of habitat variables at the presence points and the ROHH was different, indicating the species crossing the current niche range to establish in new niche. The mean diurnal range (Bio2) and annual precipitation (Bio12) variables had the lowest heterogeneity in 2050 and 2070 scenarios. This study reports that the fluctuation of habitat variables in areas with high heterogeneity was different from the current distribution range of M. peregrina. No significant fluctuation was found in the distribution range of the species in climate change scenarios.

Keywords: Environmental Heterogeneity, Climate Change, Region of High Heterogenetic, Climatic Variables

iForest 16 (1): 53-61 (2023) - doi: 10.3832/ifor4196-015
https://iforest.sisef.org/contents/?id=ifor4196-015

Research Articles: Yield of forests in Ankara Regional Directory of Forestry in Turkey: comparison of regression and artificial neural network models based on statistical and biological behaviors

Bolat F, Ercanli I, Günlü A — 2023-01-22

Bolat F, Ercanli I, Günlü A

YIELD OF FORESTS IN ANKARA REGIONAL DIRECTORY OF FORESTRY IN TURKEY: COMPARISON OF REGRESSION AND ARTIFICIAL NEURAL NETWORK MODELS BASED ON STATISTICAL AND BIOLOGICAL BEHAVIORS

Abstract: Models of forest growth and yield provide important information on stand and tree developments and the interactions of these developments with silvicultural treatments. These models have been developed based on assumptions such as independence of observations, uncorrelated error terms, and error terms with constant variance; if these factors are absent, there may be problems with multicollinearity, autocorrelation, or heteroscedasticity, respectively. These problems, which have several adverse effects on parameter estimates, are statistical phenomena and must be avoided. In recent years, the artificial neural network (ANN) model, thanks to its superior features such as the ability to make successful predictions and the absence of the requirement for statistical assumptions, has been commonly used in forestry modeling. However, while goodness-of-fit measures were taken into consideration in the assessment of ANN models, the control of the biological characteristics of model predictions was ignored. In this study, variable-density yield models were developed using nonlinear regression and ANN techniques. These modeling techniques were compared based on some goodness-of-fit measures and the principles of forest yield. The results showed that ANN models were more successful in meeting expected biological patterns than regression models.

Keywords: Bayesian, Machine Learning, Gompertz, Overfitting

iForest 16 (1): 30-37 (2023) - doi: 10.3832/ifor4116-015
https://iforest.sisef.org/contents/?id=ifor4116-015

Research Articles: Modeling compatible taper and stem volume of pure Scots pine stands in Northeastern Turkey

Saygili B, Kahriman A — 2023-01-22

Saygili B, Kahriman A

MODELING COMPATIBLE TAPER AND STEM VOLUME OF PURE SCOTS PINE STANDS IN NORTHEASTERN TURKEY

Abstract: Compatible taper and volume equations for pure and natural Scots pine stands in the northeastern part of Turkey (Ardahan Province) were developed using a nonlinear mixed-effects modeling approach. Experimental data were obtained from 137 felled sample trees in different diameter and height classes. The most successful model (Jiang et al. 2005) explained 98.3% of the variance in stem diameter estimation and the RMSE, ME, MAE, AIC and BIC value obtained using this model were 1.955 cm, 0.043 cm, 1.300 cm, 9783.8 and 9812.6, respectively. Considering the criterion values of AIC, BIC and -2LnL, the model with random-effects in two parameters (b1 and b3) was the most successful for Scots pine. While the mixed model including random parameters did not completely solved the problem of the autocorrelation of errors in this study, the use of the autoregressive error structure AR(1) eliminated the autocorrelation in the residuals. In addition, the best estimation results among 20 different calibration options were obtained using the option of measuring two tree diameters at d1.30 and d5.30 with validation data. The most successful model explained 99.18% of the total variance in stem volume estimation in Scots pine.

Keywords: Nonlinear Mixed-effects Model, Segmented Polynomial Taper Models, Calibration, Random Parameters, Autocorrelation, Stem Volume

iForest 16 (1): 38-46 (2023) - doi: 10.3832/ifor4099-015
https://iforest.sisef.org/contents/?id=ifor4099-015

Research Articles: Logging residue chipping options for short rotation poplar plantations

Spinelli R, Mihelič M, Kováč B, Heger P, Magagnotti N — 2023-01-15

Spinelli R, Mihelič M, Kováč B, Heger P, Magagnotti N

LOGGING RESIDUE CHIPPING OPTIONS FOR SHORT ROTATION POPLAR PLANTATIONS

Abstract: Short rotation poplar plantations grow on flat and even terrain, and the interrow spacing is wide enough for easy machine access. If the terrain is firm enough, one may consider moving the classic roadside chipping operation directly into the field (i.e., terrain chipping), thus saving on wood extraction cost. This study compared the efficiency and cost of roadside and terrain chipping conducted with exactly the same equipment, to assess the benefits offered by the versatile deployment of a standard chipping operation, whereby the operation can be moved inside the stand whenever terrain conditions are suitable. The study was conducted at 12 sample plots, containing about one truck load of chips each (i.e., approximately 11 bone-dry tons or BDT). Plots were arranged as alternate windrows on a 8.5 ha field. Data was collected for the whole supply chain, from field to factory. The factory was located 14 km from the field. Delivered cost was 53 € BDT-1 and 70 € BDT-1 for roadside and terrain chipping, respectively, i.e., terrain chipping was 1/3 more expensive than roadside chipping, even if the latter included the additional cost of forwarding the residues to the roadside. The chipper-truck used for the test could not cope with small scattered residue piles (32 BDT ha-1), and the cumbersome reposition maneuver became the main hurdle to efficient operation. Further improvements might be achieved by pre-bunching the residues, introducing a dedicated terrain chipper or bundling the residues and taking the bundles to the factory for centralized chipping.

Keywords: Forestry, Efficiency, Productivity, Cost

iForest 16 (1): 23-29 (2023) - doi: 10.3832/ifor4130-015
https://iforest.sisef.org/contents/?id=ifor4130-015

Research Articles: Heat treatment of poplar plywood: modifications in physical, mechanical and durability properties

2023-01-09

Marcon B, Viguier J, Candelier K, Thevenon MF, Butaud JC, Pignolet L, Gartili A, Denaud L, Collet R

HEAT TREATMENT OF POPLAR PLYWOOD: MODIFICATIONS IN PHYSICAL, MECHANICAL AND DURABILITY PROPERTIES

Abstract: Plywood made of poplar are limited to indoor usages since poplar exhibits a rather low natural durability. Recently, wood heat treatments have been applied to improve properties such as decay susceptibility and dimensional stability. This study examines the potential of exposing poplar plywood to heat treatment to extend the potential of applications of this engineered wood product to outdoor end uses, and new markets accordingly. Plywood panels were glued with two different adhesive formulations based on the same melamine-urea-formaldehyde (MUF) resin to compare their respective ability to resist to the heat treatment. These different plywoods were thermally modified in saturated steam conditions at 215 °C for 2 hours following the ThermoWood® process, up to reach 14% in mass loss. The durability improvement brought by the heat treatment was assessed in order to evaluate any possible outdoor uses for such plywood. After all the conducted analyses, the potential to use heat treated poplar plywoods in humid interior and protected exterior service conditions was confirmed.

Keywords: Heat Treatment, Plywood, Poplar, Bending Modulus of Elasticity, Bending Strength, Bond Quality, Fungal Durability, Termite Resistance

iForest 16 (1): 1-9 (2023) - doi: 10.3832/ifor4159-015
https://iforest.sisef.org/contents/?id=ifor4159-015

Review Papers: Problems and solutions to cork oak (Quercus suber L.) regeneration: a review

Mechergui T, Pardos M, Boussaidi N, Jacobs DF, Catry FX — 2023-01-09

Mechergui T, Pardos M, Boussaidi N, Jacobs DF, Catry FX

PROBLEMS AND SOLUTIONS TO CORK OAK (QUERCUS SUBER L.) REGENERATION: A REVIEW

Abstract: This study aimed to review the requirements and difficulties of natural and artificial regeneration of cork oak (Quercus suber L.) in the Mediterranean Basin. Cork oak regeneration is achieved naturally by means of sexual or vegetative reproduction (by seeds or by sprouting), or artificially through direct seeding, or seedling planting. Both natural and artificial regeneration of cork oak frequently encounter numerous difficulties which limit the ecological conditions for cork oak regeneration, including acorn predation, slow growth, vegetative competition, browsing of seedlings, fires, pests and diseases, and summer drought. We reviewed the state of the art of these difficulties and summarize the potential solutions for each regeneration form.

Keywords: Natural Regeneration, Artificial Regeneration, Direct Seeding, Plantation, Stump Sprouts

iForest 16 (1): 10-22 (2023) - doi: 10.3832/ifor3945-015
https://iforest.sisef.org/contents/?id=ifor3945-015

Research Articles: Natural regeneration and species diversification after seed-tree method cutting in a maritime pine reforestation

De Frutos S, Bravo-Fernández JA, Roig-Gómez S, Del Río M, Ruiz-Peinado R — 2022-12-14

De Frutos S, Bravo-Fernández JA, Roig-Gómez S, Del Río M, Ruiz-Peinado R

NATURAL REGENERATION AND SPECIES DIVERSIFICATION AFTER SEED-TREE METHOD CUTTING IN A MARITIME PINE REFORESTATION

Abstract: Forest adaptation to global change has become one of the main objectives of forest management in recent years. Species and structural diversification by thinning is a well-known adaptation measure, often applied by managers in monospecific even-aged stands. However, regeneration fellings may be more efficient for enhancing naturalization and resilience of monospecific reforested pine stands, widely distributed throughout the Mediterranean basin. This work focuses on the evaluation of natural regeneration after seed-tree method cuttings, adopted as a diversification strategy in a 60-year old P. pinaster reforestation with varying presence of broad-leaved species (mainly Quercus spp.) in mountains of Southern Spain. A trial consisting of 78 circular plots (1 m radius) was installed to monitor annual tree-species regeneration over seven years, classified into seedlings (0-10 cm height) and saplings (10-130 cm). Scrub coverage and other ecological variables were also measured. Sampling was carried out in three stand types (Pure, Mixed 1 and Mixed 2, in order of increasing presence of broad-leaved species), according to forest species composition before the felling. Maritime pine regeneration was successfully achieved by the end of the study period (over 2000 trees ha-1 widely distributed throughout the stand), whereas Quercus spp. seedlings even colonised plots in which there were no seed trees. Pine seedling density was positively affected by summer precipitation and the presence of conspecific adult pines, and negatively influenced by scrub coverage. High temperatures during the mid-summer months (especially August) negatively affected the seedling to sapling change ratio as well as sapling survival during the study period. Our results point to regeneration fellings with retention of pine and broadleaf species as a suitable method for diversifying species composition in Pinus pinaster reforestations in the Mediterranean region.

Keywords: Adaptation, Global Change, Mixed Forests, Naturalization, Regeneration Fellings

iForest 15 (6): 500-508 (2022) - doi: 10.3832/ifor4088-015
https://iforest.sisef.org/contents/?id=ifor4088-015

Research Articles: Seeing, believing, acting: climate change attitudes and adaptation of Hungarian forest managers

Jankó F, Bertalan L, Pappné Vancsó J, Németh N, Hoschek M, Lakatos M, Móricz N — 2022-12-14

Jankó F, Bertalan L, Pappné Vancsó J, Németh N, Hoschek M, Lakatos M, Móricz N

SEEING, BELIEVING, ACTING: CLIMATE CHANGE ATTITUDES AND ADAPTATION OF HUNGARIAN FOREST MANAGERS

Abstract: Climate change attitudes, perceptions, and adaptation activities of Hungarian forestry managers have been examined in this study through a national questionnaire and interviews. The questionnaire results revealed that respondents are mainly concerned by the decrease in snow-covered days, but differences in opinions can be attributed to geographical location and forest composition. Forest management aimed at climate change adaptation in Hungary is still in the initial phase: only 16% of respondents reported the application of climate change adaptation measures. Many foresters claim legislative constraints frequently hinder their efforts to implement such measures; those who have implemented adaptation measures show an increased concern toward climate change, on average. They have been aware of climate change for a longer time and consider it a serious problem affecting their management activities. The questionnaire results indicate that the adaptations of state forest managers are at about the same level as private foresters. Moreover, a high level of concern combined with nature conservation factors does not hinder adaptation. Nevertheless, interview respondents reported that nature conservation factors are hindrances to adaptation processes.

Keywords: Climate Change, Forestry Management, Perception, Adaptation, Hungary

iForest 15 (6): 509-518 (2022) - doi: 10.3832/ifor3958-015
https://iforest.sisef.org/contents/?id=ifor3958-015

Research Articles: Evaluation of estimation methods for fitting the three-parameter Weibull distribution to European beech forests

Bončina Z, Trifković V, Rosset C, Klopčič M — 2022-12-01

Bončina Z, Trifković V, Rosset C, Klopčič M

EVALUATION OF ESTIMATION METHODS FOR FITTING THE THREE-PARAMETER WEIBULL DISTRIBUTION TO EUROPEAN BEECH FORESTS

Abstract: We evaluated three estimation methods for fitting the three-parameter Weibull distribution to even-aged European beech (Fagus sylvatica) forests by using experimental tree diameter data collected in 3709 sample plots (500 m2 each). The maximum likelihood estimation method (MLE), the method of moments (MOM) and the method of modified moments type 1 (MM1) were applied for fitting the Weibull function. The goodness-of-fit of stand parameters (total tree number, stand basal area, dominant stand diameter and mean quadratic diameter) was tested by MAE and RMSE, and the probability and cumulative density functions of trees per 5 cm diameter classes were additionally tested by the Kolmogorov-Smirnov test and compared with Kolmogorov-Smirnov’s D statistic. All three methods are suitable for estimating stand parameters based on the fitted Weibull function. Fitting the diameter distribution per 5 cm diameter classes at the plot level was less accurate due to the low number of trees or irregular diameter distribution of trees. The MM1 method was found to be the most suitable for fitting the three-parameter Weibull distribution to beech forests represented by data derived from small plots.

Keywords: Diameter Distribution Fitting, Weibull Function, Parameter Estimation, Inventory Data, Circular Sample Plots, Near-natural Forests, Fagus Sylvatica, Slovenia

iForest 15 (6): 484-490 (2022) - doi: 10.3832/ifor4145-015
https://iforest.sisef.org/contents/?id=ifor4145-015

Research Articles: Multiscale characteristics of the early spring temperature and response to climate indices over the past 179 years in the Qinling Mountains

Zhang C, Wang J, Li S, Hou L — 2022-12-01

Zhang C, Wang J, Li S, Hou L

MULTISCALE CHARACTERISTICS OF THE EARLY SPRING TEMPERATURE AND RESPONSE TO CLIMATE INDICES OVER THE PAST 179 YEARS IN THE QINLING MOUNTAINS

Abstract: Examination of the periodic differences in temperature in the Qinling Mountains at different time scales is highly important in research on the long-term evolution of the regional climate system and ecological environment. Based on February-April temperature data from 1835 to 2013 obtained at 27 weather stations in the Qinling Mountains reconstructed through tree rings, the multiscale characteristics of the early spring temperature time series on the southern and northern slopes of the Qinling Mountains and the response to climate signals were analyzed. The results indicate that the early spring temperature in the Qinling Mountains exhibits significant periodic characteristics on multiple time scales. Reconstruction at the different time scales reveals that the interannual scale change in the temperature variation on the northern slope of the Qinling Mountains plays a decisive role. The temperature on the northern slope exhibits a higher amplitude at the interannual and interdecadal scales than does that on the southern slope, and temporal differences occur at the quasi-century scale. The temperature achieves the strongest correlation with the original Atlantic Multidecadal Oscillation (AMO) sequence during the entire study period. In addition, the different time scales reveal that a significant response relationship exists between the temperature at the interannual scale and the May sea temperature in the NINO3.4 area, which lags by one year. At the different time scales and various time ranges, the Qinling early spring temperature responds differently to the climate signals, which is an important factor leading to a lower correlation during the entire study period.

Keywords: Temperature, Ensemble Empirical Mode Decomposition, Time Scale, Qinling Mountains

iForest 15 (6): 491-499 (2022) - doi: 10.3832/ifor4069-015
https://iforest.sisef.org/contents/?id=ifor4069-015

Research Articles: Effect of forwarder multipassing on forest soil parameters changes

Pandur Z, Kopseak H, Šušnjar M, Landekić M, Šporčić M, Bačić M — 2022-11-24

Pandur Z, Kopseak H, Šušnjar M, Landekić M, Šporčić M, Bačić M

EFFECT OF FORWARDER MULTIPASSING ON FOREST SOIL PARAMETERS CHANGES

Abstract: In the lowland part of Croatia, heavy machinery such as forwarders is mainly used for the purpose of extracting wood from even-aged forest stands. According to the forest management plan, forwarders are used intensively in the winter period when the soil is mostly saturated with water and when their activity can cause significant damage to the soil. The aim of this study was to determine changes in soil characteristics as a consequence of the repeated passage of a loaded 8-wheel forwarder on silty clay loam type of soil. The research was conducted in an area where the forwarder usually works and in a way that did not significantly disrupt his normal workflow. The results indicate that during the study period the soil had a good bearing capacity and that the observed changes in soil characteristics (bulk density, total soil porosity, soil moisture, particle density, soil water retention capacity etc.) occurred as a result of breaking structural soil aggregates after soil compaction by multiple passes. Characteristic points (T) of equalized penetration curves indicate the compaction of the soil surface layer. Cone penetration index (CI) values did not show a proportional increase as the number of forwarder passes increased, although significant differences in their values with respect to the number of passes were found. Shear strength (τ) did not significantly increase with increasing the number of passes, but a statistically significant difference in the measured values was detected at the soil surface, which was not observed at a depth of 15 cm. Exceeding the rut depth limit of 10 cm occurred only after the 20th pass. Our results indicate that the soil at the harvesting site had a good bearing capacity during the study period.

Keywords: Silty Clay Loam, Bulk Density, Cone Index, Shear Strength, Ruts Depth

iForest 15 (6): 476-483 (2022) - doi: 10.3832/ifor4138-015
https://iforest.sisef.org/contents/?id=ifor4138-015

Research Articles: Impact of deforestation on the soil physical and chemical attributes, and humic fraction of organic matter in dry environments in Brazil

2022-11-18

Souza Rezende J, Freire FJ, Araújo Filho JCD, Dos Santos Freire MBG, Gomes de Almeida B, Costa Santos LR

IMPACT OF DEFORESTATION ON THE SOIL PHYSICAL AND CHEMICAL ATTRIBUTES, AND HUMIC FRACTION OF ORGANIC MATTER IN DRY ENVIRONMENTS IN BRAZIL

Abstract: Deforestation of Caatinga and inadequate land use of these dry environments have impacted soil quality in Northeastern Brazil. The objectives of this study were: (a) to evaluate the effect of deforestation and different agricultural uses on the physical and chemical properties of soil, and humic fractions of soil organic matter in dry environments; and (b) to detect the soil properties that were most affected by anthropic actions. We evaluated four dry areas in Chapada do Araripe, NE Brazil: preserved native vegetation; degraded native vegetation; cassava conventional cultivation; and eucalyptus agro-energy cultivation. Soil fertility, total organic carbon and humic fractions of soil organic matter were lower in the degraded native vegetation area. The best indicators for soil quality evaluation were: macroporosity; bulk density; soil resistance penetration; sum of bases (mainly Ca2+); available P; and saturation by Al3+. Total organic carbon and humic acid fractions of soil organic matter were important in improving soil quality. These properties were influenced by deforestation and agricultural uses, suggesting that the deforestation of native vegetation in dry environments has high capacity to degrade the soil, preventing its regeneration.

Keywords: Degraded Soil, Forest Soil, Land Use Change, Soil Quality

iForest 15 (6): 465-475 (2022) - doi: 10.3832/ifor4016-015
https://iforest.sisef.org/contents/?id=ifor4016-015

Research Articles: Estimating the potential threat of increasing temperature to the forests of Turkey: a focus on two invasive alien insect pests

Ipekdal K — 2022-11-03

Ipekdal K

ESTIMATING THE POTENTIAL THREAT OF INCREASING TEMPERATURE TO THE FORESTS OF TURKEY: A FOCUS ON TWO INVASIVE ALIEN INSECT PESTS

Abstract: Rising temperature can affect forests negatively through its impact on insect pests. The present study focused on two invasive alien insect species (Dryocosmus kuriphilus and Leptoglossus occidentalis) to understand how rising temperature might affect their damage in Turkish forests. For D. kuriphilus, the timing of chestnut budburst, gall induction and emergence of its introduced parasitoid, Torymus sinensis, were monitored between 2015 and 2019, and each phenological event was compared annually with fluctuations in temperature to observe the parasitoid-host synchrony. For L. occidentalis, cumulative degree days (CDD) were calculated, and the possible number of generations produced in 2020 in different regions of Turkey were predicted. The CDD calculations were repeated under increasing temperature and different photoperiod-diapause induction scenarios. Evaluation of the monitoring data on the D. kuriphilus system showed that gall induction occurred at the same time as budburst, whereas T. sinensis emergence was independent from the budburst, and that the parasitoid-host synchrony was disrupted after the abnormally warm winter in 2018. The CDD calculations estimated that L. occidentalis produced one to five generations from north to south in 2020. They also suggested a significant increase in the number of generations in the southern Turkey under temperature increase scenarios. Including photoperiod as a time-limiting factor reduced the highest possible number of generations from five to two. In conclusion, rising temperature has a potential to threaten the biocontrol against D. kuriphilus, and it can increase voltinism in L. occidentalis.

Keywords: Dryocosmus kuriphilus, Leptoglossus occidentalis, Asynchrony, Voltinism, Climate Change

iForest 15 (6): 444-450 (2022) - doi: 10.3832/ifor3960-015
https://iforest.sisef.org/contents/?id=ifor3960-015

Research Articles: Above ground biomass estimation from UAV high resolution RGB images and LiDAR data in a pine forest in Southern Italy

2022-11-03

Maesano M, Santopuoli G, Moresi FV, Matteucci G, Lasserre B, Scarascia Mugnozza G

ABOVE GROUND BIOMASS ESTIMATION FROM UAV HIGH RESOLUTION RGB IMAGES AND LIDAR DATA IN A PINE FOREST IN SOUTHERN ITALY

Abstract: Knowledge of forest biomass is an essential parameter for managing the forest in a sustainable way, as forest biomass data availability and reliability are necessary for forestry and forest planning, but also for the carbon market as well as to support the local economy in the mountain and inner areas. However, the accurate quantification of the above-ground biomass (AGB) is still a challenge both at the local and global levels. The use of remote sensing techniques with Unmanned Aerial Vehicle (UAV) platforms can be an excellent trade-off between resolution, scale, and frequency data of AGB estimation. In this study, we evaluated the combined use of RGB images from UAV, LiDAR data and ground truth data to estimate AGB in a forested watershed in Southern Italy. A low-cost AGB estimation method was adopted using a commercial fixed-wing drone equipped with an RGB camera, combined with the canopy information derived by LiDAR and validated by field data. Two modelling methods (stepwise regression, SR and random forest, RF) were used to estimate forest AGB. The output was an accurate maps of AGB for each model. The RF model showed better accuracy than the Steplm model, and the R2 increased from 0.81 to 0.86, and the RMSE and MAE values were decreased from 45.5 to 31.7 Mg ha-1 and from 34.2 to 22.1 Mg ha-1 respectively. We demonstrated that by increasing the computing efficiency through a machine learning algorithm, readily available images can be used to obtain satisfactory results, as proven by the accuracy of the Random forest above biomass estimation model.

Keywords: Above Ground Biomass, UAV, Random Forest, Forest Biomass, Machine Learning

iForest 15 (6): 451-457 (2022) - doi: 10.3832/ifor3781-015
https://iforest.sisef.org/contents/?id=ifor3781-015

Research Articles: Fuel characterization and crown fuel load prediction in non-treated Calabrian pine (Pinus brutia Ten.) plantation areas

Yurtgan M, Baysal I, Küçük O — 2022-11-03

Yurtgan M, Baysal I, Küçük O

FUEL CHARACTERIZATION AND CROWN FUEL LOAD PREDICTION IN NON-TREATED CALABRIAN PINE (PINUS BRUTIA TEN.) PLANTATION AREAS

Abstract: Successful management of young, fire-prone Calabrian pine forests requires an accurate characterization of surface and canopy fuel loads at stand level. This study characterizes the surface and canopy fuel characteristics in unthinned Calabrian pine plantations in Turkey. Fifteen sample plots were measured to determine the surface and crown fuel characteristics of very young, young and middle aged Calabrian pine stands (10 to 28 years old). Thirty-six trees were destructively sampled to quantify the crown fuel loads and canopy fuel characteristics of the stands. Surface fuel load ranged from 11.38 t ha-1 in the young stands to 35.27 t ha-1 in the middle aged stands. Dead fuel load as ladder fuels on the trees ranged from 0.77 kg in very young stands to 13.56 kg in the young stands. Live fuel loads on the trees ranged from 0.77 kg to 23.29 kg in the young aged stands. Total active crown fuel load was 58.7%, 52.1% and 49.5% of total crown fuel load in very young, young and middle aged stands, respectively. Our results improve the current crown fuel model predictions and showed the importance of dead fuel load in fire management studies both for the determination of crown fuel loads and the calculation of carbon stocks.

Keywords: Surface Fuel, Dead Crown Fuel, Live Crown Fuel, Non-treated, Pinus brutia, Türkiye

iForest 15 (6): 458-464 (2022) - doi: 10.3832/ifor4048-015
https://iforest.sisef.org/contents/?id=ifor4048-015

Research Articles: Do different indices of forest structural heterogeneity yield consistent results?

Reich KF, Kunz M, Bitter AW, Von Oheimb G — 2022-10-20

Reich KF, Kunz M, Bitter AW, Von Oheimb G

DO DIFFERENT INDICES OF FOREST STRUCTURAL HETEROGENEITY YIELD CONSISTENT RESULTS?

Abstract: Forest management with a focus on high structural heterogeneity is a major goal in modern forestry to increase multifunctionality. The assessment and quantification of forest structures has, therefore, gained much attention in recent years. However, there is no standardized approach to surveying forest heterogeneity; instead, a variety of structural indices, which have been developed over past decades, are used. This makes it difficult to interpret the results of different studies and to base management decisions on such data. In this study, we compared six structural indices that differ in terms of their complexity and the method of data acquisition. These included the Gini coefficient of the diameter at breast height and of tree height, the Shannon index of tree species diversity, two complex indices of structural heterogeneity, one based on conventional inventory data and one on terrestrial laser scanning (TLS) data, and a simple-holistic TLS-based stand structural complexity index. For the comparison of these six indices, we used data from 84 plots in 12 different forest stand types in two study areas in Germany. The stand types consisted of different dominant tree species and included different age classes. The degree of correlations among the different indices was highly variable. In addition, we did not find a clear age-dependency of the indices. We conclude that the choice of a specific index plays an important role in the evaluation and interpretation of forest structural heterogeneity. Because TLS data offer multiple benefits in terms of precision, reproducibility and comprehensiveness, we recommend to use TLS-based indices of structural heterogeneity.

Keywords: Forest Structure, Shannon Index, Gini Coefficient, Stand Structural Complexity Index, Structural Heterogeneity Index

iForest 15 (5): 424-432 (2022) - doi: 10.3832/ifor4096-015
https://iforest.sisef.org/contents/?id=ifor4096-015

Research Articles: Impact of rotation length of Eucalyptus globulus Labill. on wood production, kraft pulping, and forest value

2022-10-20

Resquin F, Fariña I, Rachid-Casnati C, Rava A, Doldán J, Hirigoyen A, Inderkum F, Alen S, Morales Olmos V, Carrasco-Letelier L

IMPACT OF ROTATION LENGTH OF EUCALYPTUS GLOBULUS LABILL. ON WOOD PRODUCTION, KRAFT PULPING, AND FOREST VALUE

Abstract: Most of the wood from Eucalyptus globulus Labill. plantations in Uruguay is harvested for pulp industry at an average age of 11 years. In this study we evaluated the volume and quality of the wood produced and the economic return for owners using different rotation length (from 6 to 13 years) and two different provenances (Jeeralang, Australia and Chivilingo, Chile) in experimental plots planted at two different sites (southwest and southeast of Uruguay). Silvicultural practices, industrial process, and economic aspects of the plantations were evaluated by measuring the following variables: survival, individual and per hectare growth, basic density, cellulose yield, wood consumption, cellulose production per hectare, dry solids content, fiber length, paper resistance, internal rate of return, and soil expectation value. The results showed that an increase in the harvest age generates: (i) an increase in the production of wood and cellulose per hectare at decreasing rates; (ii) an increase in wood density and yield; (iii) a reduction in the consumption of wood and solid contents in the cooking liquor; and (iv) a reduction in economic profitability at the farm level. No differences were found in the fiber length and resistance properties of the paper from wood harvested at different ages.

Keywords: Eucalyptus globulus, Harvest Age, Pulping Kraft, Fiber Length, Forest Value

iForest 15 (5): 433-443 (2022) - doi: 10.3832/ifor4040-015
https://iforest.sisef.org/contents/?id=ifor4040-015

Research Articles: Light availability influences the invasion of Teline monspessulana (L.) K. Koch in a temperate fragmented forest in Central Chile

Gómez P, Espinoza S, Cuadros N, Goncalves E, Bustamante R — 2022-10-19

Gómez P, Espinoza S, Cuadros N, Goncalves E, Bustamante R

LIGHT AVAILABILITY INFLUENCES THE INVASION OF TELINE MONSPESSULANA (L.) K. KOCH IN A TEMPERATE FRAGMENTED FOREST IN CENTRAL CHILE

Abstract: The Maulino forest is a temperate ecosystem of the Mediterranean zone of Chile classified as one of the 34 biodiversity hot-spots of the world; however, there is still limited information about the ecological factors that make this native forest prone to be invaded. We assess to what extent forest attributes such as light availability and native species diversity control the invasion process of Teline monspessulana (L.) K. Koch, an aggressive weed, into the Maulino forest, an endemic forest ecosystem of Central Chile. We examined whether the seedling density of this exotic plant is related to forest attributes such as cover, incoming photosynthetically active radiation, litter depth, and native species density and richness. We found that a decrease of light availability reduces T. monspessulana invasion. No relationships were observed between native species diversity and the abundance of T. monspessulana plants. Increasing the forest cover will recover forest structure but at the same time, it will prevent the invasion of T. monspessulana and other exotic plants with similar regeneration niche requirements.

Keywords: Invasibility, Invasiveness, French Broom, Genista monspessulana, Forest Cover, Native Species Diversity

iForest 15 (5): 411-416 (2022) - doi: 10.3832/ifor4026-015
https://iforest.sisef.org/contents/?id=ifor4026-015

Research Articles: Suitability of Fagus orientalis Lipsky at marginal Fagus sylvatica L. forest sites in Southern Germany

Mellert KH, Šeho M — 2022-10-19

Mellert KH, Šeho M

SUITABILITY OF FAGUS ORIENTALIS LIPSKY AT MARGINAL FAGUS SYLVATICA L. FOREST SITES IN SOUTHERN GERMANY

Abstract: European beech (Fagus sylvatica L.) is the most important tree species in Central Europe and is considered to be relatively resistant to climate warming. However, dry summers in the last five years led to considerable damage in beech stands in Southern Germany (SG). Assisted migration of drought resistant beech provenances including those of Oriental beech (Fagus orientalis Lipsky) may help to stabilise Central European beech forests under climate change. The focus of this study is to compare the climatic ranges of F. sylvatica and F. orientalis using quantile distribution of climatic variables based on WorldClim data at forest sites within their natural distribution area. Temperature, precipitation, and aridity quantile ranges showed that F. orientalis is better adapted to warmer and drier climate compared to F. sylvatica. The quantile distribution method was applied to the whole range of the species to map the habitat suitability for both species at marginal sites in the target region (SG) in the current climatic scenario (1970-2000) and in a warmer scenario (+2°C) using the climate marginality index (CMI), i.e., the distance of sites to the xeric edge at low-latitude and low-altitude distribution limits for the species. To this purpose we applied the simple BIOCLIM algorithm using annual temperature and precipitation as climatic variables. According to our results, F. orientalis seems a promising species with a high potential for future afforestation activities in Southern Germany, especially at marginal sites of European beech forests. However, before introducing F. orientalis on a larger scale in the study area, further research on the species ecology and genetics are needed. For further application of the quantile range method, we produced tables of the vigintiles of the climatic range for both species, which can be used for estimating CMI based on WorldClim data in other regions.

Keywords: BIOCLIM, Climate Change, Climatic Marginality Index, Climatic Range, Ellenberg Quotient, Macroecology, Quantile Distribution, Species Distribution

iForest 15 (5): 417-423 (2022) - doi: 10.3832/ifor4077-015
https://iforest.sisef.org/contents/?id=ifor4077-015

Research Articles: Nursery screening of poplar and willow clones for biofuel application in Ukraine

Kutsokon N, Rakhmetov D, Rakhmetova S, Khudolieieva L, Rashydov N — 2022-10-06

Kutsokon N, Rakhmetov D, Rakhmetova S, Khudolieieva L, Rashydov N

NURSERY SCREENING OF POPLAR AND WILLOW CLONES FOR BIOFUEL APPLICATION IN UKRAINE

Abstract: Poplars and willows are fast-growing trees that can be effectively grown as a renewable energy source. This study was devoted to the preliminary screening of poplar and willow clones for biofuel application in a fast-growing tree nursery established in the M.M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine. The nursery includes 19 Populus and 10 Salix clones, with many hybrids of Ukrainian origin. The clones were assessed in the first two years in the nursery using growth parameters, biomass fuel criteria, and susceptibility to pathogens. Using total rank for evaluation, the highest rank was found in the poplar clone “Kanadska × balsamichna” followed by the clones “Ivantiivska”, “Volosystoplidna”, “Perspektyvna”, and “Nocturn”. Among the willows, the highest rank was recorded for the clone “Zhytomyrska-1”, followed by clone “Zhytomyrska-2”. High ranks were also found in the poplars “Strilopodibna”, “Mobilna”, “Novoberlinska-7” and “Keliberdynska”, and the willows “Lisova pisnya” and “Vinnytska”. Thus, the above-mentioned clones may be recommended as promising trees, though they should be further evaluated under field conditions for growth performance within the short-rotation cycles. The clones with the lowest total rank were poplars “Bolle”, “Gradizka” and “Kytaiska × piramidalna” and willows “Lukash”, “Olimpiisky vohon” and “Pryberezhna” are not recommended for bioenergy short-rotation plantations. Evaluation of plants in the nursery allowed us to carry out rapid and cost-effective preliminary screening. Such multiclonal screening of bioenergy trees for planting in short rotations was described for the first time in Ukraine.

Keywords: Tree Biomass, Short-Rotation Plantations, Growth Parameters, Wood Biofuel Properties, Pathogen Tolerance

iForest 15 (5): 401-410 (2022) - doi: 10.3832/ifor3732-015
https://iforest.sisef.org/contents/?id=ifor3732-015

Research Articles: NIR-based models for estimating selected physical and chemical wood properties from fast-growing plantations

Assis Loureiro B, Arriel TG, Guedes Ramalho FM, Hein PRG, Trugilho PF — 2022-10-05

Assis Loureiro B, Arriel TG, Guedes Ramalho FM, Hein PRG, Trugilho PF

NIR-BASED MODELS FOR ESTIMATING SELECTED PHYSICAL AND CHEMICAL WOOD PROPERTIES FROM FAST-GROWING PLANTATIONS

Abstract: As a faster, reliable, and low cost technique, applicable to large samplings, near infrared (NIR) spectroscopy technology has been widely applied for high-throughput phenotyping in forest breeding programmes. The aim of this study was to develop multivariate models for estimating the chemical and physical properties of juvenile wood based on NIR signatures of milled wood. Moreover, two approaches, namely, external validation by clone and by age, were tested to validate the model for estimating extractive content. NIR spectra of wood specimens taken from three clones of Eucalyptus urophylla (one to six years old) grown in southern Brazil were used to calibrate and validate models for predicting the wood basic density, total extractives, ash content, holocellulose content, syringyl to guaiacyl ratio (S/G) and elementary components of the wood. PLS-R models were validated by an independent set of wood specimens and presented promising statistics for the estimating wood density (R2p = 0.768), extractives (R2p = 0.912), ash (R2p = 0.936) and carbon (R2p = 0.697) contents from NIR signatures measured in the milled wood of young trees. Furthermore, NIR models for estimating the extractive content of wood were validated using the clones or ages left out of the training sets. Most models presented satisfactory statistics (R2 > 90%) and could be applied to routine laboratory analyses or to select potential trees in Eucalyptus breeding programmes.

Keywords: Near Infrared, Wood Analysis, Predictive Models, Wood Powder, Eucalyptus, Multivariate Analysis

iForest 15 (5): 372-380 (2022) - doi: 10.3832/ifor4030-015
https://iforest.sisef.org/contents/?id=ifor4030-015

Research Articles: Effects of mixture and management on growth dynamics and responses to climate of Quercus robur L. in a restored opencast lignite mine

Manetti MC, Mazza G, Papini L, Pelleri F — 2022-10-05

Manetti MC, Mazza G, Papini L, Pelleri F

EFFECTS OF MIXTURE AND MANAGEMENT ON GROWTH DYNAMICS AND RESPONSES TO CLIMATE OF QUERCUS ROBUR L. IN A RESTORED OPENCAST LIGNITE MINE

Abstract: Opencast mining is currently one of the most destructive economic activities of natural ecosystems. Many restoration techniques have been developed to promote the recovery of terrestrial ecosystems degraded by mining, and afforestation and reforestation are among the most important methods to this purpose. In this study, we evaluated the combined effect of tree species mixture and thinning intervention on growth dynamics and responses to the climate of a target native planted oak (pedunculate oak, Quercus robur L.) about 40 years after reforestation of an opencast lignite mining area in Central Italy. The species used for reforestation were a native tree species (Q. robur L.), two valuable broadleaved trees (Fraxinus angustifolia Vahl. and Prunus avium L.) and a nitrogen-fixing tree (Alnus cordata Loisel.) to improve timber quality and restore the ecological and environmental value of the degraded land. Climate-growth relationships for precipitation, the Standardised Precipitation-Evaporation Index (SPEI), and temperature (on a monthly and seasonal scale) were tested together with indices based on tree-ring responses to drought. Thinning improved the stem quality and promoted a significant long-term increase in basal area increment (BAI, +31.0%) only in the mixture with alder. The thinning effect slightly mitigated radial growth reductions of oak trees during drought (resistance) and produced a general improvement in the magnitude of resilience and post-drought growth recovery (+37% and +27% on average, respectively). This effect was most evident when oak trees were mixed with only the N-fixing alder species, both after shorter- and longer-term drought or rainfall reduction. In conclusion, the mixture with alder combined with thinning practices resulted in the best management option to produce good-quality stems, improve growth performances, and mitigate drought effects in the recovery of opencast lignite mines through reforestation.

Keywords: Mixed Plantation, Tree Rings, Basal Area Increment, Mine Restoration, N-fixing Species, Linear Mixed Models, Pedunculate Oak

iForest 15 (5): 391-400 (2022) - doi: 10.3832/ifor4108-015
https://iforest.sisef.org/contents/?id=ifor4108-015

Research Articles: Impact of inbreeding on growth and development of young open-pollinated progeny of Eucalyptus globulus

Faia J, Costa J, Araújo J, Borralho N, Marques C, Trindade H — 2022-09-20

Faia J, Costa J, Araújo J, Borralho N, Marques C, Trindade H

IMPACT OF INBREEDING ON GROWTH AND DEVELOPMENT OF YOUNG OPEN-POLLINATED PROGENY OF EUCALYPTUS GLOBULUS

Abstract: The use of open-pollinated seeds from seed orchards is a common strategy for the deployment of genetically improved eucalypts, including Eucalyptus globulus, an important pulpwood tree in many temperate climate areas. However, seed quality can be affected by the rate of selfing and to a lesser extent by contamination from pollen outside the orchard. Inbreeding between related parents and especially from self-crosses is known to cause diminished growth and developmental abnormalities in the resulting progeny. This study looks at the magnitude and variation in selfing and the impact in inbreeding depression across several E. globulus families collected over the years in a seed orchard. The effects on growth and development of outcrossed and selfed progeny were studied across five progeny trials, after pedigree reconstruction of the open pollinated progeny based on SSR genotyping. An additive genetic mixed linear model was fitted to the data to evaluate the impact of inbreeding on height growth. The results showed a significant inbreeding depression, with a height growth reduction of 15% in selfed progeny, when compared with crosses from unrelated parents. These inbreeding depression values varied among families, ranging between 7% and 24%, evidencing the importance of genetic background. Contamination rates were on average 10% suggesting long distance pollen dispersal was present. A small number of abnormal phenotypes (less than 10%) was observed in the field. This was associated with specific, unrelated, crosses and not to high inbreeding rates such as found among selfed progeny. The relevance of these results for orchard management and parent selection is discussed.

Keywords: Inbreeding Depression, Seed Orchard, Selfing, Abnormal Phenotypes, SSRs, Pedigree Reconstruction

iForest 15 (5): 356-362 (2022) - doi: 10.3832/ifor4012-015
https://iforest.sisef.org/contents/?id=ifor4012-015

Research Articles: Predictive capacity of nine algorithms and an ensemble model to determine the geographic distribution of tree species

2022-09-20

Montoya-Jiménez JC, Valdez-Lazalde JR, Ángeles-Perez G, De Los Santos-Posadas HM, Cruz-Cárdenas G

PREDICTIVE CAPACITY OF NINE ALGORITHMS AND AN ENSEMBLE MODEL TO DETERMINE THE GEOGRAPHIC DISTRIBUTION OF TREE SPECIES

Abstract: The different models that predict the distribution of species are a useful tool for the evaluation and monitoring of forest resources as they facilitate the planning of their management in a changing climate environment. Recently, a significant number of algorithms have been proposed for this purpose, making it difficult to select the most appropriate to use. The evaluation of performance and predictive stability of these models can elucidate this problem. Distribution data of 17 pine species with high economic importance for Mexico were collected and distribution models were carried out. We carried out a pre-modeling design to select the prediction variables (climatic, edaphic and topographic), after which nine algorithms and an ensemble model were contrasted against one another. The true skill statistic (TSS) and the area under the curve (AUC) were used to evaluate the predictive performance of the models, and the coefficient of variation of the predictions was used to evaluate their stability. The number of predictive variables in the final models fluctuated from 6 to 12; the mean diurnal range and the maximum temperature of warmest month were included in the models for most species. Random forests, the ensemble model, generalized additive models and MaxEnt were the ones that best described the distribution of the species (AUC >0.92 and TSS >0.72); the opposite was found in Bioclim and Domain (AUC<0.75 and <0.82; and TSS<0.5 and <0.55). Support vector machine, Mahalanobis distance, generalized linear models and boosted regression trees obtained intermediate settings. The coefficient of variation indicated that Bioclim, Domain and Support vector machine have low predictive stability (CV>0.055); on the contrary, Maxent and the ensemble model attained high predictive stability (CV<0.015). The ensemble model obtained greater performance and predictive stability in the predictions of the distribution of the 17 species of pines. The differences found in performance and predictive stability of the algorithms suggest that the ensemble model has the potential to model the distribution of tree species.

Keywords: TSS, AUC, BRT, SVM, MaxEnt, Random Forests, GAM, Ensemble Model

iForest 15 (5): 363-371 (2022) - doi: 10.3832/ifor4084-015
https://iforest.sisef.org/contents/?id=ifor4084-015

Research Articles: Effects of functional traits on the spatial distribution and hyperdominance of tree species in the Cerrado biome

2022-09-01

De Souza HJ, Miguel EP, Resende RT, Matricardi EAT, Rezende AV, Leal FA, Dos Santos ML

EFFECTS OF FUNCTIONAL TRAITS ON THE SPATIAL DISTRIBUTION AND HYPERDOMINANCE OF TREE SPECIES IN THE CERRADO BIOME

Abstract: The ecological influence of functional traits on species persistence as well as on their role over the organization of forest communities in the Brazilian Cerrado biome have not been fully understood yet. In this study, we assessed the effects of six functional groups, characterized by three seed dispersal syndromes (i.e., anemochory, autochory, and zoochory) and three wood density classes (i.e., hardwood, lightwood, and softwood), on tree spatial distribution patterns, habitat occupancy, and ecosystem services (biomass hyper dominance and abundance) provided by a forest community located in the “Parque do Lajeado”, state of Tocantins, Brazil. The similarity among study sites was characterized by applying the tree dominant height approach and the environmental and soil variables as input. The floristic similarity was assessed by applying the Bray-Curtis index. The zoochoric species showed more aggregated spatial pattern at local scale, which indicates that it is more sensitive to environmental gradients than other dispersal syndromes. Meanwhile, hardwood density species were more established in the community, being more persistent to environmental filters. We observed that a small number of species contributed with about 50% of the abundance and biomass of the community, whose functional traits (wood density and dispersal syndrome) indirectly affect the relationship among the community species richness and their ecosystem functions. We observed that the functional traits related to seed dispersal and wood density functional groups resulted in different spatial distribution patterns of those tree species. Therefore, functional traits and environmental factors combined have substantially affected the structure and composition of forest communities at local scale.

Keywords: Seed Dispersal, Wood Density, Species Abundance Distribution, Spatial Patterns, Brazilian Savanna

iForest 15 (5): 339-348 (2022) - doi: 10.3832/ifor3920-015
https://iforest.sisef.org/contents/?id=ifor3920-015

Research Articles: Physiological dormancy and dormancy release of Sassafras tzumu, a colored-leaf tree species with high landscape and economic value

Chen H, Jiang J, Liu J, Tan Z, Li Y — 2022-09-01

Chen H, Jiang J, Liu J, Tan Z, Li Y

PHYSIOLOGICAL DORMANCY AND DORMANCY RELEASE OF SASSAFRAS TZUMU, A COLORED-LEAF TREE SPECIES WITH HIGH LANDSCAPE AND ECONOMIC VALUE

Abstract: Sassafras tzumu is one of the most valuable tree species in southern China. However, the dormancy of the seed limits its seedling quality. In order to improve the germination percentage of seeds, characteristics, causes of dormancy, changes in endogenous hormones and nutrients during storage were investigated. The results showed that seed viability was 78.11%, and the highest water absorption rate was 26.09%. The germination percentage of the embryo without cotyledon was 21.13%, but intact seed and embryo could not germinate on hormone-free medium. Seed embryo and coat extracts were found to have a significant inhibitory effect on seed germination. Germination percentage were significantly positively correlated to free amino content (p < 0.01) and negatively correlated to soluble sugar content (p < 0.05) during storage. The levels of GA3 and GA3/ABA had significant effects on the germination percentage of S. tzumu seed storage at 4°C. The results suggest that S. tzumu seeds are in intermediate physiological dormancy at maturity and are mainly caused by the presence of inhibitory substances in the seed tissues. Furthermore, changes in endogenous hormones and metabolism of nutrients at 4°C can significantly promote the release from dormancy of S. tzumu seeds.

Keywords: Sassafras tzumu, Seed Dormancy, Wet Sand Storage, Phytohormones, Nutrients

iForest 15 (5): 349-355 (2022) - doi: 10.3832/ifor4031-015
https://iforest.sisef.org/contents/?id=ifor4031-015

Research Articles: Seed germination traits of Pinus heldreichii in two Greek populations and implications for conservation

Daskalakou EN, Koutsovoulou K, Oikonomidis S, Thanos CA — 2022-08-24

Daskalakou EN, Koutsovoulou K, Oikonomidis S, Thanos CA

SEED GERMINATION TRAITS OF PINUS HELDREICHII IN TWO GREEK POPULATIONS AND IMPLICATIONS FOR CONSERVATION

Abstract: Seed germination traits were assessed on Pinus heldreichii H. Christ, a Tertiary relict, high-elevation Mediterranean pine, endemic in the western Balkan Peninsula and southern Italy; it is naturally grown at the northern Greece mountains, but also found in shrubby form above the timberline. Closed and mature cones were collected (October) for three consecutive years from Pindos Range and Mt. Olympus populations. Cone and seed morphological traits were recorded along with the seedling cotyledon number. Seed germination tests were performed under various ecologically meaningful temperatures and light regimes; climate change effects on seed germination and seedling development were assessed based on two climate scenarios. Final seed germination was moderate (~55%) on both, untreated seed lots at most favourable conditions (15 and 20 °C). Although cold stratification is not an absolute requirement, seed germination rate and final percentage are promoted by both a month of cold stratification (at least 30 or 45 days) and white light. The predicted climate change suggests that a prolonged drought period (>3 months) might turn out by the end of the century in the populations studied. Although the temperature increase might not have significant effects in the germination window of the species. The rainfall decrease will inevitably expose the young seedlings to the summer drought, thus increasing the potential mortality rate. Both ex situ (e.g., germplasm conservation) and in situ measures of conservation are recommended for the species survival in Greece, with a particular focus on the populations established at lower altitudes.

Keywords: Climate Change, Cold Stratification, Cotyledon Number, Heldreich’s Pine, Light Response, Seed Ecophysiology, Seed Mass

iForest 15 (4): 331-338 (2022) - doi: 10.3832/ifor4045-015
https://iforest.sisef.org/contents/?id=ifor4045-015

Research Articles: Contribution of anthropogenic, vegetation, and topographic features to forest fire occurrence in Poland

2022-08-23

Ciesielski M, Balazy R, Borkowski B, Szczesny W, Zasada M, Kaczmarowski J, Kwiatkowski M, Szczygiel R, Milanovic S

CONTRIBUTION OF ANTHROPOGENIC, VEGETATION, AND TOPOGRAPHIC FEATURES TO FOREST FIRE OCCURRENCE IN POLAND

Abstract: Climate is one of the main causes of forest fires in Europe. In addition, forest fires are influenced by other factors, such as the reconstruction of tree stands with a uniform species composition and increasing human pressure. At the same time, the increasing number of fires is accompanied by a steady increase in the number and quality of spatial information collected, which affects the ability to conduct more accurate studies of forest fires. The appropriate use of spatial information systems (GIS) together with all the collected information on fires could provide new insights into their causes and, in further steps, allow the development of new, more accurate predictive models. The objectives of the study were: (i) to estimate the probability of fire occurrence in the period 2007-2016; (ii) to evaluate the performance of the developed model; (iii) to identify and quantify anthropogenic, topographic and stand factors affecting the probability of fire occurrence in forest areas in Poland. To achieve these objectives, a statistical model based on a logistic regression approach was built using the nationwide forest fire database for the period from 2007 to 2016. The information in the database was obtained from the Polish State Forest Information System (SILP). Then it was supplemented with spatial, topographic and socio-economic information from various spatial and statistical databases. The results showed that fire probability is significantly positively affected by population density and distance from buildings. In addition, the further the distance from roads and railways, watercourses and water objects or the edge of the forest, height above sea level, and steep slopes, the lower is the fire probability. Analysis of spatial, ecological and socio-economic factors provides new insights that contribute to a better understanding of fire occurrence in Poland.

Keywords: Forest Fires, Logistic Regression, Variables Selection, Anthropogenic Factors

iForest 15 (4): 307-314 (2022) - doi: 10.3832/ifor4052-015
https://iforest.sisef.org/contents/?id=ifor4052-015

Research Articles: The patterns of nearest neighbor trees in a temperate forest

Chen X, Bowman KA — 2022-08-23

Chen X, Bowman KA

THE PATTERNS OF NEAREST NEIGHBOR TREES IN A TEMPERATE FOREST

Abstract: The nearest neighbor trees (NNTs) are essential for reflecting forest structure and spatial heterogeneity in a forest stand. It is not clear whether different tree species have varied patterns of NNTs in a small area due to biological interactions, whether big trees affect the nearest neighbors for diversity and recruitments, or whether a universal linear relationship between the distance of NNTs and their average DBH exists. In this study, the information of NNTs at two plots (each 30 × 100 m) in a temperate mixed broadleaved forest in Southern USA was collected by field survey. Our results indicated that approximately 80% of NNTs were within a distance of 1.5-4.0 m. Tulip poplar, oaks, and hickory trees did not have the same species as NNTs or were very limited. Carolina buckthorn had itself as an NNT but with fewer other species. Sugar maple could serve as the NNT for oaks, hickory and others. The relationships between the distance of an NNT and its cumulative percentage were different among varied species or groups. Overall, for trees and their NNTs, there existed complicated relationships between their sizes (e.g., height and DBH). Big trees might affect NNTs in diversity and recruitment. The suggested linear relationship between tree size and distance was not observed. The results could be helpful to manage forest structure (tree species and NNT) and provide evidence to improve the scaling theory on NNTs.

Keywords: Forest Structure, Heterogeneity, Scaling, Species Interaction, Tree Size

iForest 15 (4): 315-321 (2022) - doi: 10.3832/ifor4035-015
https://iforest.sisef.org/contents/?id=ifor4035-015

Research Articles: Effect of dust accumulation on Quercus cerris L. leaves in the Ezer forest, Lebanon

Najib R, Houri T, Khairallah Y, Khalil M — 2022-08-23

Najib R, Houri T, Khairallah Y, Khalil M

EFFECT OF DUST ACCUMULATION ON QUERCUS CERRIS L. LEAVES IN THE EZER FOREST, LEBANON

Abstract: Air pollution arising from different sources represents a serious environmental threat to all living organisms, including vegetation. Monitoring air contamination levels is necessary to detect pollution levels, regulate atmospheric pollution, and ultimately improve ambient air quality. The current study evaluated the effects of air pollutants with a focus on dust and some biochemical and physiological properties of Quercus cerris L., which is growing in Lebanon’s Ezer forest, threatened by the presence of a public road on its northern side. The studied parameters include leaf extract pH, stomatal conductance, relative water content, hydrogen peroxide, proline, carotenoids, and air pollution tolerance index. These parameters can provide reliable information about the tolerance status of plants towards pollutants. Three sites with different exposure to vehicular activities were used to conduct this study, including a control site (unpolluted) and two polluted sites (S1 and S2). The results showed a significant reduction in stomatal conductance and relative water content at polluted sites compared with the control site. Hydrogen peroxide, proline, and carotenoids showed the highest levels at the S2 site, which is indicative of the fact that Quercus cerris undergoes established physiological and biochemical changes in response to environmental stress. Based on the air pollution tolerance index (4.97-9.85) Quercus cerris is categorized as a sensitive species that can be used as a biological monitor of environmental pollution. Thus, the development and implementation of efficient environmental action plans based on biomonitoring should be considered for protecting the forests.

Keywords: Ezer Forest, Quercus cerris L., Dust, Physiological Parameters, Biochemical Parameters, Bioindicator

iForest 15 (4): 322-330 (2022) - doi: 10.3832/ifor3959-015
https://iforest.sisef.org/contents/?id=ifor3959-015

Research Articles: Complex networks, an innovative methodology for functional zoning in forest management

2022-08-22

Serrano-Ramírez E, Valdez-Lazalde JR, Mora-Gutiérrez RA, De Los Santos-Posadas HM, Ángeles-Pérez G

COMPLEX NETWORKS, AN INNOVATIVE METHODOLOGY FOR FUNCTIONAL ZONING IN FOREST MANAGEMENT

Abstract: Forest management planning requires a permanent collection of data on the distribution, composition, and structure of the stands that conform a woodland. These data serve as the basis for suggesting the most appropriate management scheme according to the natural resource conditions and management objectives. It is common for the collected databases’ structure and dimension to hinder their analysis using traditional descriptive techniques. Therefore, alternative methodologies are required to facilitate both the exploration of data properties and their collective behavior. We used complex networks analysis to identify distribution patterns of topographic, biological, and productive conditions of a managed forest, suggesting its functional zoning. The forest was considered a graph consisting of nodes and edges; the stands served as nodes and interactions between them as edges. Degree, clustering coefficient, triangles, and modularity were used as segregation and connectivity metrics to evaluate forest properties and allocate stands to five predefined potential forest uses (zones). The clustering coefficient metric provided the better graph partition, allowing to obtain the best alternatives for zoning the forest in conservation areas, areas with potential for timber production, and carbon storage. Proposing forest functional zoning through complex network theory is a powerful methodological option to represent the spatial and nonspatial interactions among the relevant attributes defining a forest ecosystem condition.

Keywords: Forest Planning, Spatial Interactions, Segregation And Connectivity Metrics, Graph Theory

iForest 15 (4): 299-306 (2022) - doi: 10.3832/ifor3927-015
https://iforest.sisef.org/contents/?id=ifor3927-015

Research Articles: Monitoring of the incidence of Dutch Elm Disease and mortality in experimental plantations of French Ulmus minor clones

Collin E, Pozzi T, Joyeau C, Matz S, Rondouin M, Joly C — 2022-07-29

Collin E, Pozzi T, Joyeau C, Matz S, Rondouin M, Joly C

MONITORING OF THE INCIDENCE OF DUTCH ELM DISEASE AND MORTALITY IN EXPERIMENTAL PLANTATIONS OF FRENCH ULMUS MINOR CLONES

Abstract: The results of 16 experimental plantations of Ulmus minor clones of the French national collection are presented as a complement to a previous work (Collin et al. 2020) on the outcome of the French Programme for the Conservation of Native Elm Genetic Resources. A total of 710 elms from 38 clones were planted in three different regions of France using two types of experimental designs and exposed to natural infection by Dutch Elm Disease (DED). DED infection and subsequent mortality were monitored in rectangular monospecific plantations (“plot-tests”), comprising at least 100 elms (10 clones). Linear plantations of 15 to 36 elms intermixed with other trees and shrubs (“hedge-tests”) investigated the feasibility of using native field elm clones in hedge reconstruction projects. After at least 9 (up to 17) years of experimentation, overall DED infection frequency was 33%, with scores above 63% in the oldest plantation and in two fast-growing tests. The overall mortality in the 232 diseased trees was 21%, reaching 29% in the oldest plantation and 64% in a hedge-test on high quality soil, suggesting a possible effect of the very fast growth of the trees. A few clones showed an interesting lower infection frequency or some ability to recover, whereas some others were found quickly infected in several tests and could serve in future experiments on clone attractiveness for DED vectors. Practical conclusions for genetic resources conservation consist of recommendations for the establishment of conservation plantations using regional clones.

Keywords: Ulmus minor, Plantation, Dutch Elm Disease, Ophiostoma novo-ulmi, Genetic Resources, France

iForest 15 (4): 289-298 (2022) - doi: 10.3832/ifor3820-015
https://iforest.sisef.org/contents/?id=ifor3820-015

Research Articles: Allometric models for the estimation of foliage area and biomass from stem metrics in black locust

Tziaferidis SR, Spyroglou G, Fotelli MN, Radoglou K — 2022-07-27

Tziaferidis SR, Spyroglou G, Fotelli MN, Radoglou K

ALLOMETRIC MODELS FOR THE ESTIMATION OF FOLIAGE AREA AND BIOMASS FROM STEM METRICS IN BLACK LOCUST

Abstract: Allometric equations relating trees’ vascular system and other stem metrics with foliage area and mass are important to estimate their growth, carbon stocks and interactions with abiotic environment in terms of carbon and water balance. In this study we focused on Robinia pseudoacacia restoration plantations in Greece and aimed at establishing species-specific models to predict foliage leaf area and biomass based on stem traits. In particular, we evaluated stem cross-sectional areas of sapwood, current sapwood and total stem (sapwood and heartwood), measured at different tree heights, as predictors of leaf area and mass, based on the pipe model theory. Furthermore, we assessed the variation in the ratios of leaf area to different stem cross-sectional areas across the tree profile and we examined the relationships of diameter at breast height (DBH) with diameter at the base of the live crown and with leaf area. Taking into account the trees’ DBH distribution according to the plantations’ inventory, 25 black locust individuals were destructively sampled and the relationships among the studied traits were analyzed by means of multiple and simple linear regression at p<0.001. Foliage dry mass and area were best predicted by total stem cross-sectional area at mid-bole and stump height (R2=0.81), followed by current sapwood area at stump height (R2=0.74), which outperformed the most often used sapwood area (R2=0.70). DBH was also reliably estimating tree leaf area (R2=0.72) but was less precise, compared to total cross-sectional area, while it was a useful proxy of diameter at the base of the live crown (R2=0.80). In line with the pipe model theory, the ratio of leaf area to total cross-sectional area declined across the canopy basipetally, but only when total cross-sectional area was considered. Deviations from the sapwood-foliage functions described by the pipe model theory may be due to the small sample size and the variability in tree size in such developing restoration plantations. The produced species-specific relationships between stem and foliage metrics may be a useful tool to predict the carbon sequestration and climate change adaptation potential of black locust restoration plantations, which are often characterized by harsh site conditions.

Keywords: Sapwood Area, Current Sapwood Area, Total Cross-sectional Area, Diameter at Breast Height, Diameter at Live Crown Base, Leaf Area, Foliage Dry Weight, Robinia pseudoacacia

iForest 15 (4): 281-288 (2022) - doi: 10.3832/ifor3939-015
https://iforest.sisef.org/contents/?id=ifor3939-015

Research Articles: Edge tree functional traits and their association with edaphic factors in seasonally dry forests in northern Thailand

Asanok L, Taweesuk R, Kamyo T — 2022-07-26

Asanok L, Taweesuk R, Kamyo T

EDGE TREE FUNCTIONAL TRAITS AND THEIR ASSOCIATION WITH EDAPHIC FACTORS IN SEASONALLY DRY FORESTS IN NORTHERN THAILAND

Abstract: The relationships between plant traits and soil properties in forest edges can provide insights into tree species recovery in edge habitats. In this study, we investigated the relationships between plant functional traits and soil conditions related to tree species recovery at the edges of two seasonally dry forests, a mixed deciduous forest (MDF) and a deciduous dipterocarp forest (DDF) in northern Thailand. We analyzed differences in functional trait diversity and community-level trait values between forests and performed RLQ analysis to assess the associations among species abundance, plant traits, and soil variables. We found that the MDF site had greater functional diversity and was dominated by plants with high specific leaf area (SLA) and leaf dry-matter content (LDMC) at the community level, whereas the DDF site had lower diversity and was dominated by plants with high wood density (WD) and leaf thickness (LT). The RLQ results indicated that at the MDF site, tree species with greater SLA (e.g., Pterocarpus macrocarpus, Dalbergia cultrata, and Phanera bracteata) were associated with soil clay content and nutrient status (i.e., nitrogen and calcium). Species with greater LDMC and leaf size (e.g., Xylia xylocarpa, Schleichera oleosa, and Chukrasia tabularis) were associated with soil organic matter content. At the DDF site, species with greater WD and LT (e.g., Dipterocarpus obtusifolius, Shorea siamensis, and Buchanania lanzan) were associated with soil sand content and bulk density. These patterns reflect the interplay between soil conditions and plant traits in the edge habitats of seasonally dry forests. Our results indicate that the edge effects on plant communities within seasonally dry forests depend on soil conditions and species-specific plant traits.

Keywords: Forest Edge Effects, Tree Species Recovery, Plant-soil Relationships, Mixed Deciduous Forest, Deciduous Dipterocarp Forest

iForest 15 (4): 273-280 (2022) - doi: 10.3832/ifor3870-015
https://iforest.sisef.org/contents/?id=ifor3870-015

Research Articles: Variability of tolerance of Wild cherry clones to PEG-induced osmotic stress in vitro

Vuksanović V, Kovačević B, Stojnić S, Kebert M, Kesić L, Galović V, Orlović S — 2022-07-25

Vuksanović V, Kovačević B, Stojnić S, Kebert M, Kesić L, Galović V, Orlović S

VARIABILITY OF TOLERANCE OF WILD CHERRY CLONES TO PEG-INDUCED OSMOTIC STRESS IN VITRO

Abstract: The effects of drought simulated via osmotic stress induced by polyethylene glycol (PEG) in the growing medium were examined on two Wild cherry (Prunus avium L.) clones (6A and 8A) based on thirteen morphometric, physiological, and biochemical traits. The shoot tips were exposed to two PEG concentrations (20 and 50 g L-1) in growing medium designed for micropropagation with axillary buds. The results showed that all morphological and physiological traits were significantly reduced, indicating a strong detrimental effect of increased PEG concentrations. The significant decline of radical scavenging activity against ABTS•+ and total content of flavonoids (TFC) and phenols (TPC) were recorded in both clones as a response to high PEG concentrations, whereas opposite trends were noticed for ferric reducing antioxidant power (FRAP). Clone 8A achieved better performance, having more intensive growth, higher multiplication percentage, higher values of carotenoids, more intense decrement of ABTS and increment of FRAP values compared to the clone 6A. The results of the principal component analysis indicate that parameter TFC/TPC in both stem and leaves, as well as TFC in the stems, achieved the strongest relation with morphometric parameters. Our results confirm the feasibility of in vitro evaluation of drought tolerance of Wild cherry, supporting further research on the variability of examined traits in this noble broadleaved tree species.

Keywords: Drought, Selection, Prunus avium, Tissue Culture, Oxidative Stress

iForest 15 (4): 265-272 (2022) - doi: 10.3832/ifor4033-015
https://iforest.sisef.org/contents/?id=ifor4033-015

Research Articles: Reversible and irreversible effects of mild thermal treatment on the properties of wood used for making musical instruments: comparing mulberry to spruce

2022-07-20

Karami E, Brémaud I, Bardet S, Almeras T, Guibal D, Langbour P, Pourtahmasi K, Gril J

REVERSIBLE AND IRREVERSIBLE EFFECTS OF MILD THERMAL TREATMENT ON THE PROPERTIES OF WOOD USED FOR MAKING MUSICAL INSTRUMENTS: COMPARING MULBERRY TO SPRUCE

Abstract: Thermal treatments can be considered as an accelerated ageing, bringing partly similar changes in properties as naturally aged wood. Thermal treatment was applied on white mulberry (Morus alba L.), a dominant species for making musical instruments from middle-East to Far-East, to investigate the effects on the vibro-mechanical and physical properties of this wood, and the results compared to previously published data on spruce (Picea abies Karst.) as a reference for the soundboard of Western string instruments. Thermal treatment (TT) at 150 °C and 0% of relative humidity was applied to five analogous groups of specimens with five different durations (2.5, 8, 24, 72, 261 hours). Humidity re-conditioning of specimens was done to explore the reversibility of TT effects. Physical and vibrational properties such as specific gravity (γ), equilibrium moisture content (EMC), CIELab colorimetric values, specific modulus of elasticity (E’/γ) and damping coefficient (tanδ) in longitudinal (L) and radial (R) directions, have been measured after stabilisation of samples in standard conditions (20 °C, 65% RH), before and after TT and then after re-conditioning. Untreated mulberry had a low EMC, very low L/R anisotropy and low E’L/γ, and relatively low tanδ. Weight loss (WL) and CIELab values evolved similarly during TT for mulberry and for previous results on spruce, however, their EMC and vibrational properties were affected differently. This could be explained in part by the low anisotropy of mulberry, and in part by its particular extractives. The parts of irreversible effects, linked to chemical modification or degradation, and of reversible effects, linked to physical configuration, were different between mulberry and spruce. The applied treatments did not bring permanent “improvements” in vibrational properties of mulberry, yet its colour appearance was enhanced.

Keywords: Anisotropy, CIELab, Morus alba, Musical Instruments, Reconditioning, Thermal Treatment, Vibrational Properties

iForest 15 (4): 256-264 (2022) - doi: 10.3832/ifor4074-015
https://iforest.sisef.org/contents/?id=ifor4074-015

Research Articles: Growing at the forest edges: how natural regeneration develops under fragmentation

Pereira Gomes L, Borges Dias P, Machado Dias H, Horn Kunz S — 2022-07-19

Pereira Gomes L, Borges Dias P, Machado Dias H, Horn Kunz S

GROWING AT THE FOREST EDGES: HOW NATURAL REGENERATION DEVELOPS UNDER FRAGMENTATION

Abstract: Environmental changes caused by edge effects and matrix land use can interfere with plant community resilience and, consequently, alter forest succession. Here, we aimed to (i) investigate whether species composition, density and richness in a forest’s regeneration layer vary in its edge-to-interior gradient and (ii) analyze the relationship between regeneration and local abiotic variables. We conducted the study in the lowland rainforest of the Atlantic Forest biodiversity hotspot at the Córrego Grande Biological Reserve, Espírito Santo state, Brazil. We sampled the regeneration layer in two edge environments with different matrices (forest and road) and the fragmented interior to link vegetation structure with environmental variables. In each environment, we set up 12 plots of 5 × 10 m size and recorded, in each plot, the height and stem base diameter of all living individuals above 50 cm of height and below 2.5 cm of diameter at breast height (1.30 m height). We applied different multivariate analyses to assess the influence of environmental data, such as canopy openness and physical-chemical soil variables. The three environments shared 22 out of the 174 morphospecies recorded, and the forest-side edge had the lowest species richness among all environments. The environmental variables that better explained the distribution of species across the three environments were: canopy openness, soil penetration resistance, zinc, and calcium content. Our results revealed significant environmental differences among the forest edges and the forest interior of the study site, highlighting the relevant role of the forest surrounding matrix for the maintenance of protected remnants.

Keywords: Seedling, Forest Resilience, Biological Reserve, Environmental Variables

iForest 15 (4): 248-255 (2022) - doi: 10.3832/ifor3834-015
https://iforest.sisef.org/contents/?id=ifor3834-015

Research Articles: Identification of wood from the Amazon by characteristics of Haralick and Neural Network: image segmentation and polishing of the surface

2022-07-14

de Souza Vieira GL, Moutinho da Ponte MJ, Pereira Moutinho VH, Jardim-Gonçalves R, Pantoja Lima C, de Albuquerque Vinagre MV

IDENTIFICATION OF WOOD FROM THE AMAZON BY CHARACTERISTICS OF HARALICK AND NEURAL NETWORK: IMAGE SEGMENTATION AND POLISHING OF THE SURFACE

Abstract: The identification of Amazonian timber species is a complex problem due to their great diversity and the lack of leaf material in the post-harvest inspection often hampers a correct recognition of the wood species. In this context, we developed a pattern recognition system of wood images to identify commonly traded species, with the aim of increasing the accuracy and efficiency of current identification methods. We used ten different species with three polishing treatments and twenty images for each wood species. As for the image recognition system, the textural segmentation associated with Haralick characteristics and classified by Artificial Neural Networks was used. We verified that the improvement of sandpaper granulometry increased the accuracy of species recognition. The developed model based on linear regression achieved a recognition rate of 94% in the training phase, and a post-training recognition rate of 65% for wood treated with 120-grit sandpaper mesh. We concluded that the wood pattern recognition model presented has the potential to correctly identify the wood species studied.

Keywords: Wood Identification, Amazon, Technology, Pattern Recognition, Digital Image Processing, Artificial Neural Networks

iForest 15 (4): 234-239 (2022) - doi: 10.3832/ifor3906-015
https://iforest.sisef.org/contents/?id=ifor3906-015

Research Articles: Afforestation monitoring through automatic analysis of 36-years Landsat Best Available Composites

2022-07-12

Cavalli A, Francini S, Cecili G, Cocozza C, Congedo L, Falanga V, Spadoni GL, Maesano M, Munafò M, Chirici G, Scarascia Mugnozza G

AFFORESTATION MONITORING THROUGH AUTOMATIC ANALYSIS OF 36-YEARS LANDSAT BEST AVAILABLE COMPOSITES

Abstract: The study of afforestation is crucial to monitor land transformations and represents a central topic in sustainable development procedures, in terms of climate change, ecosystem services monitoring, and planning policies activities. Although surveying afforestation is important, the assessment of the growing forests is difficult, since land cover has different durations depending on the species. In this context, remote sensing can be a valid instrument to evaluate the afforestation process. Nevertheless, while a vast literature on forest disturbance exists, only a few studies focus on afforestation and almost none directly exploits remote sensing data. This study aims to automatically classify non-forest, afforestation, and forest areas using remote sensing data. To this purpose, we constructed a reference dataset of 61 polygons that suffered a change from non-forest to forest in the period 1988-2020. The reference data were constructed with the Land Use Inventory of Italy and through photointerpretation of orthophotos (1988-2012, spatial resolution 50 × 50 cm) and very high-resolution images (2012-2020, spatial resolution 30 × 30 cm). Using Landsat Best Available Pixel composites time-series (1984-2020) we calculated 52 temporal predictors: four temporal metrics (median, standard deviation, Pearson’s correlation coefficient R, and slope) calculated for 13 different bands (the six Landsat spectral bands, three Spectral Vegetation Indices, and four Tasseled Cap Indices). To verify the possibility of distinguishing afforestation from non-forest and forest, given the differences between them can be minimal, we tested four different models aiming at classifying the following categories: (i) non-forest/afforestation, (ii) afforestation/forest, (iii) non-forest/forest and (iv) non-forest/afforestation/forest. Temporal predictors were used with random forest which was calibrated using random search, validated using k-fold Cross-Validation Overall Accuracy (OAcv), and further using out-of-bag independent data (OAoob). Results illustrate that the distinction of afforestation/forest reaches the largest OAcv (87%), followed by non-forest/forest (83%), non-forest/afforestation (75%) and non-forest/afforestation/forest (72%). The different OA values confirm that the difference in photosynthetic activity between forest and afforestation can be analysed through remote sensing to distinguish them. Although remote sensing data are currently not exploited to monitor afforestation areas our results suggest it may be a valid support for country-level monitoring and reporting.

Keywords: Afforestation, Remote Sensing, Land Cover Monitoring, Random Forest

iForest 15 (4): 220-228 (2022) - doi: 10.3832/ifor4043-015
https://iforest.sisef.org/contents/?id=ifor4043-015

Commentaries & Perspectives: Forest plantations with public subsidies: to harvest or not to harvest, this is the question

Olmo V, Sigura M, Alberti G — 2022-07-12

Olmo V, Sigura M, Alberti G

FOREST PLANTATIONS WITH PUBLIC SUBSIDIES: TO HARVEST OR NOT TO HARVEST, THIS IS THE QUESTION

Abstract: In the last three decades the European Union has supported the afforestation of lands previously devoted to agriculture through targeted subsidies, thus enhancing the provision of many ecosystem services (ESs). However, most of these plantations are close or even above the minimum permanence period and will be likely eradicated by landowners to restore the previous land use (i.e., croplands). In this scenario, the investments for carbon (C) sequestration will be nullified and the supply of many other ESs, which have developed along with plants growth, will be drastically reduced. In this commentary, using as reference a case study in the Friuli Venezia Giulia Autonomous Region (NE Italy), we quantify the value of wood production and C sequestration ESs of tree plantations, simulating a present and a future scenario. Our simulations show that by extending the permanence of these stands for 20 more years, a 34% increase of biomass annual Net Present Value will be expected on average, according to its final use. Regarding C sequestration, a total C stock of 167 tC ha-1 can be estimated in 40 years, corresponding to a cumulative Net Present Value of more than 11 million euro. Thus, if C sequestration is considered, the overall annual Net Present Value shows a 35% increase on average, when compared to a reconversion to corn. These data suggest the need for a new national and European strategy, which not only considers well-planned new afforestation campaigns, but also aims at maintaining at least part of the afforested lands, thus maximizing ESs and supporting high quality wood production. At the end of the rotation period, new cycles can be promoted on the same surfaces through natural gamic or agamic regeneration. An additional important aspect to consider is also related to the active management of these stands, thus to improve their growth (quantity and quality), in situ C storage as well as storage in final products.

Keywords: EU-afforestation Policy, Carbon Sequestration, Italy, Reg. 2080/92, Wood Quality

iForest 15 (4): 229-233 (2022) - doi: 10.3832/ifor3943-015
https://iforest.sisef.org/contents/?id=ifor3943-015

Review Papers: Biomass, radial growth and regeneration capacity of Aleppo pine, and its possible use as rootstock in arid and degraded areas

Mechergui K, Naghmouchi S, Alsubeie MS, Jaouadi W, Ammari Y — 2022-06-16

Mechergui K, Naghmouchi S, Alsubeie MS, Jaouadi W, Ammari Y

BIOMASS, RADIAL GROWTH AND REGENERATION CAPACITY OF ALEPPO PINE, AND ITS POSSIBLE USE AS ROOTSTOCK IN ARID AND DEGRADED AREAS

Abstract: This paper reviews recent findings on Aleppo pine (Pinus halepensis Mill.), which is found throughout the Mediterranean region and has been introduced in several areas of the world. This species is used in reforestation efforts for timber production and protection of degraded areas. Several studies have shown that this species has high biomass productivity and high plasticity. Its radial growth is influenced by the climate and the physical environment. Aleppo pine is known for its great capacity for expansion in its natural environment and its great capacity for invasion in areas where it has been introduced worldwide. The use of P. halepensis Mill. as rootstock has yielded satisfactory resultsin the production of stone pine cones and nuts in marginalized, arid, and dry areas. This review can help forest managers developing optimal management strategies for Aleppo pine stands in arid and sub-arid Mediterranean regions.

Keywords: Pinus halepensis Mill., Biomass, Radial Growth, Regeneration, Grafting, Arid Land

iForest 15 (3): 213-219 (2022) - doi: 10.3832/ifor3954-015
https://iforest.sisef.org/contents/?id=ifor3954-015

Research Articles: Changes in tree layer and altitudinal distribution of herbaceous species in temperate old-growth forests over 30 years

Unar P, Janík D, Adam D, Holík J — 2022-06-11

Unar P, Janík D, Adam D, Holík J

CHANGES IN TREE LAYER AND ALTITUDINAL DISTRIBUTION OF HERBACEOUS SPECIES IN TEMPERATE OLD-GROWTH FORESTS OVER 30 YEARS

Abstract: Temperate forest ecosystems, including old-growth fragments, are subject to increasing pressures, both from biotic and abiotic factors. Frequent disturbance events, rising mean annual temperatures and longer-lasting droughts are causing changes in tree species composition, probably shifting the altitudinal distribution of herbaceous species as well. Our goal was to examine whether such shifts can be observed even in old-growth temperate forests, and if the changes in the species composition and spatial distribution of trees is reflected in the herbaceous layer. Our study was based on a survey of several old-growth forests from the 1970s that was repeated after 30 years. Using spatial point pattern methods and generalized linear mixed effect models, repeated measurements of mapped phytosociological relevés and detailed maps of tree positions from two survey periods allowed us to examine how the species composition of the herb layer and the spatial distribution of trees ≥ 10 cm DBH (diameter at breast height) changed over 30 years. On most of the studied sites, the total number of trees declined and the proportion of broadleaves increased between the two surveys. Analyses of tree spatial distribution showed a general shift from a regular spatial distribution in the 1970s to a clustered spatial distribution of trees in the 2000s. In the 2000s, herbaceous species showed an upwards shift in their distribution compared to the 1970s, even after accounting for the effect of changing tree spatial distributions in both survey periods. These effects could be an outcome of warmer and drier weather conditions during the past decades. Further investigation is needed to examine whether this trend is related to changes in climatic conditions.

Keywords: Herb Layer, Species Presence, Forest Structure, Altitude, Climate Conditions

iForest 15 (3): 206-212 (2022) - doi: 10.3832/ifor3749-015
https://iforest.sisef.org/contents/?id=ifor3749-015

Research Articles: Soil of the parent plant and AMF mix improve Cerrado’s seedlings growth in forest nurseries

Abreu GM, Paiva HND, Megumi Kasuya MC, Paula SDD, Guirardi BD, Araújo GDM — 2022-05-28

Abreu GM, Paiva HND, Megumi Kasuya MC, Paula SDD, Guirardi BD, Araújo GDM

SOIL OF THE PARENT PLANT AND AMF MIX IMPROVE CERRADO’S SEEDLINGS GROWTH IN FOREST NURSERIES

Abstract: The soil microbiota plays an extremely important role in the growth and survival of plants. The presence of some microorganisms can positively and significantly impact the growth of tree species, which can improve the performance of seedlings after planting for commercial purposes and/or for ecosystem restoration. The present study aimed to evaluate the initial growth of seedlings of Hancornia speciosa and Brosimum gaudichaudii associated with microorganisms from the soil of the parent tree and/or inoculated with arbuscular mycorrhizal fungi (AMF). Four substrates were tested: T1 (control) = Autoclaved dystrophic Red-Yellow Latosol (Aut-dRYL) + autoclaved commercial substrate (Aut-CS); T2 = Aut-dRYL + Aut-CS + inoculum of AMF (Mix); T3 = Aut-dRYL + Aut-CS + soil of the parent plant (SPP); and T4 = Aut-dRYL + Aut-CS + SPP + Mix. The AMF inoculum comprised a mix of the species Gigaspora decipiens, Rhizophagus clarus, and Scutellospora heterogama. Seedling growth was determined 270-350 days after transplanting by measuring the following parameters: mycorrhizal colonization rate (MC), abundance of spores (AS), height (H), stem diameter (D), H/D ratio, volume of roots (VR), dry matter of shoot (SDM), roots (RDM), total (TDM), shoot / root dry matter ratio (SDM/RDM), height / shoot dry matter ratio (H/SDM), and Dickson quality index (DQI). The results showed that the addition of SPP improved the growth and DQI of the seedlings, while the AMF mix minimally changed both growth and DQI. The use of symbiotic microorganisms in the nursery in Brazil is scarse due to the difficulty of acquiring these microorganisms and the lack of commercialization of specific isolates for species native to the Cerrado biome. The present study evaluated the use of soil from naturally occurring areas as a source of inoculum. The higher growth and biomass production of inoculated plants support the use of SPP as a form of inoculum and/or inoculation with native AMF to produce seedlings of H. speciosa and B. gaudichaudii.

Keywords: Forest Nurseries, Biological Inoculants, Dickson Quality Index

iForest 15 (3): 197-205 (2022) - doi: 10.3832/ifor3833-015
https://iforest.sisef.org/contents/?id=ifor3833-015

Research Articles: Stem profile of red oaks in a bottomland hardwood restoration plantation forest in the Arkansas Delta (USA)

Tian N, Gan J, Pelkki M — 2022-05-19

Tian N, Gan J, Pelkki M

STEM PROFILE OF RED OAKS IN A BOTTOMLAND HARDWOOD RESTORATION PLANTATION FOREST IN THE ARKANSAS DELTA (USA)

Abstract: Bottomland hardwoods are among the most diverse and productive forest ecosystems in the southeastern United States and are critically important for the provision of timber and non-timber ecosystem services. Red oaks, the dominant species in this group of forests, are of high ecological and economic value. Stem profile models are essential for accurately estimating the merchantable volume of oak trees, which is also closely indicative of total tree biomass and other ecosystem services given their allometric relationships. This study aims to develop and compare stem profiles among three red oak species in an 18-year old plantation forest using destructive sampling. Sixty trees randomly selected from an oak restoration plantation in the Arkansas Delta were felled for measuring the diameter-outside-bark (DOB) and diameter-inside-bark (DIB) at different stem heights. These sample composed of twenty trees from each of three species: cherry bark oak (CBO - Quercus pagoda Raf), Nuttall oak (NUT - Quercus texana Buckley), and Shumard oak (SHU - Quercus shumardii Buckl). Multiple models, including the segmented-profile model, form-class profile model, and second-and third-order polynomial models were fitted and compared. Results demonstrate that the form-class profile model was the best fitted for CBO and NUT, whereas the third-order polynomial model was the best for SHU. CBO tends to grow taller and has a higher wood density than NUT and SHU. These findings will inform restoration and management decisions of bottomland hardwood forests, especially red oaks in the region.

Keywords: Cherry Bark Oak, Nuttall Oak, Shumard Oak, Taper Models, Wood Density, Southeastern United States

iForest 15 (3): 179-186 (2022) - doi: 10.3832/ifor4057-015
https://iforest.sisef.org/contents/?id=ifor4057-015

Research Articles: The effects of forest management on biodiversity in the Czech Republic: an overview of biologists’ opinions

Kjučukov P, Hofmeister J, Bače R, Vítková L, Svoboda M — 2022-05-19

Kjučukov P, Hofmeister J, Bače R, Vítková L, Svoboda M

THE EFFECTS OF FOREST MANAGEMENT ON BIODIVERSITY IN THE CZECH REPUBLIC: AN OVERVIEW OF BIOLOGISTS’ OPINIONS

Abstract: Europe has been dominated by cultural landscape and rather intensively managed forests. It is thus no surprise that the ongoing global biodiversity crisis as well as the consequences of climate change have been apparent. In recent years, forestry in Central Europe has been going through a crisis caused by extensive disturbances primarily in commercial monocultures; this phenomenon is particularly striking in the Czech Republic. Given the significance of the situation, it is essential to review and optimise the current forest management practices in relation to biodiversity protection. Therefore, a survey among Czech biologists was conducted in an effort to provide specific feedback to foresters and other stakeholders based on scientific and empirical knowledge of the survey respondents. The survey assessed the forest habitat (in terms of light conditions and the structure of the forest environment), forest management tools and conceptual approaches regarding specific species and groups of organisms. The respondents negatively perceived the current forestry practices, especially in terms of creating homogeneity across the forest environment and eliminating important habitats. Structurally diverse old-growth forests as well as the open forests with the presence of old and habitat trees were emphasised by the survey respondents as essential environments. Large-scale non-intervention within protected areas is necessary to support the presence of old-growth forests. On the other hand, there is an urgent need to restore open forests which requires (but not exclusively) the active efforts of man. These two basic appeals are essential in order to diversify the landscape through a combination of segregative and integrative forest management tools that aim to support biodiversity.

Keywords: Biodiversity Conservation, Forest Management Approaches, Key Habitats, Questionnaire Survey

iForest 15 (3): 187-196 (2022) - doi: 10.3832/ifor3953-015
https://iforest.sisef.org/contents/?id=ifor3953-015

Research Articles: The effects of fire on Pinus sylvestris L. as determined by dendroecological analysis (Sierra de Gredos, Spain)

Génova M, Ortega P, Sadornil E — 2022-05-09

Génova M, Ortega P, Sadornil E

THE EFFECTS OF FIRE ON PINUS SYLVESTRIS L. AS DETERMINED BY DENDROECOLOGICAL ANALYSIS (SIERRA DE GREDOS, SPAIN)

Abstract: Iberian populations of Scots pine (Pinus sylvestris L.) have been declining since the late-glacial period; among those that remain, relict stands have great biological and ecological value. This paper investigates the effects of a 2009 fire on tree growth in one of these small populations in the Sierra de Gredos (Spain) by examining the responses recorded in the tree-ring width series of the surviving trees. The current status and distribution of these surviving trees reveal the severity of the fire; indeed most show scars or other evidence of fire damage. Dendroecological analysis revealed narrower tree rings, indicating negative pointer years for the year of the fire and the following year. A very significant reduction in growth was recorded for the years after the fire, both in terms of tree-ring width and basal area increment; incomplete and even absent rings were also recorded. No relationship was seen between these effects and climatic events. The dates and geographical extension of former possible disturbances were also investigated, using the data from these same trees plus information collected from others in the region. The vulnerability of these populations to past fires was evident. Lastly, given the problems affecting the regeneration of these relict populations, it is strongly suggested to urgently include all these populations in conservation and environmental management programs.

Keywords: Disturbances, Tree-ring Width, Growth Change, Absent Rings, Negative Pointer Years

iForest 15 (3): 171-178 (2022) - doi: 10.3832/ifor3727-015
https://iforest.sisef.org/contents/?id=ifor3727-015

Research Articles: Impacts of stump harvesting on carbon dioxide, methane and nitrous oxide fluxes

Vestin P, Mölder M, Kljun N, Cai Z, Hasan A, Holst J, Klemedtsson L, Lindroth A — 2022-05-07

Vestin P, Mölder M, Kljun N, Cai Z, Hasan A, Holst J, Klemedtsson L, Lindroth A

IMPACTS OF STUMP HARVESTING ON CARBON DIOXIDE, METHANE AND NITROUS OXIDE FLUXES

Abstract: During 2010-2013, we investigated the effects of stump harvesting on greenhouse gas (GHG) fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) with the flux-gradient technique at four experimental plots in a hemiboreal forest in Sweden. All plots were clear-cut and soil scarified and two of the plots were additionally stump harvested. The two clear-cut plots served as control plots. Due to differences in topography, we had one wetter and one drier plot of each treatment. All plots exhibited substantial emissions of GHGs and we noted significant effects of wetness on CO2, CH4 and N2O fluxes within treatments and significant effects of stump harvesting on CO2 and N2O fluxes at the dry plots. The CO2 emissions were lower at the dry stump harvested plot than at the dry control, but when estimated emissions from the removed stumps were added, total CO2 emissions were higher at the stump harvested plot, indicating a small enhancement of soil respiration. In addition, we noted significant emissions of N2O at this plot. At the wet plots, CO2 emissions were higher at the stump harvested plot, also suggesting a treatment effect but differences in wetness and vegetation cover at these plots make this effect more uncertain. At the wet plots, we noted sustained periods (weeks to months) of net N2O uptake. During the year with simultaneous measurements of the abovementioned GHGs, GHG budgets were 1.224×103 and 1.442×103 gm-2 of CO2-equivalents at the wet and dry stump harvested plots, respectively, and 1.070×103 and 1.696×103 gm-2 of CO2-equivalents at the wet and dry control plots, respectively. CO2 fluxes dominated GHG budgets at all plots but N2O contributed with 17% at the dry stump harvested plot. For the full period 2010-2013, total carbon (CO2+CH4) budgets were 4.301×103 and 4.114×103 g m-2 of CO2-eqvivalents at the wet and dry stump harvest plots, respectively and 4.107×103 and 5.274×103 gm-2 of CO2-equivalents at the wet and dry control plots, respectively. Our results support recent studies suggesting that stump harvesting does not result in substantial increase in CO2 emissions but uncertainties regarding GHG fluxes (especially N2O) remain and more long-term measurements are needed before robust conclusions can be drawn.

Keywords: CO2, CH4, N2O, Greenhouse Gas Budget, Stump Harvesting, Climate Change Mitigation, Forest Management, Hemiboreal Forest

iForest 15 (3): 148-162 (2022) - doi: 10.3832/ifor4086-015
https://iforest.sisef.org/contents/?id=ifor4086-015

Research Articles: Assessment of land sensitivity to degradation using MEDALUS model - a case study of Grdelica Gorge and Vranjska Valley (southeastern Serbia)

2022-05-07

Lukić S, Baumgertel A, Obradović S, Kadović R, Beloica J, Pantić D, Miljković P, Belanović Simić S

ASSESSMENT OF LAND SENSITIVITY TO DEGRADATION USING MEDALUS MODEL - A CASE STUDY OF GRDELICA GORGE AND VRANJSKA VALLEY (SOUTHEASTERN SERBIA)

Abstract: Land degradation is a complex issue caused by diverse drivers, each of which should be considered in the analysis of land sensitivity to degradation. This study identifies the areas most sensitive to land degradation in the Grdelica Gorge and Vranjska Valley, which are unique in terms of natural and socioeconomic conditions. Land-use changes and inappropriate land management have led to serious degradation in this region. The flexible and multifactorial approach of the Mediterranean Desertification and Land Use (MEDALUS) model allowed comprehensive land degradation sensitivity analysis in the study area. The main factors driving soil degradation were assessed by estimating climate quality index, soil quality index, and vegetation quality index, and the main socioeconomic indicators by management quality index and social quality index. The results showed that forest cover is the main factor to contrast land degradation, and even minor adverse changes in forest characteristics, such as structure, canopy cover, health, and quality, could trigger degradation processes. The vegetation quality index was defined in terms of the current vegetation’s capacity to protect soil from erosion, drought resistance, and fire risk. Detailed data on forest vegetation cover was obtained from the National Forest Inventory (NFI). The environmentally sensitive area (ESA) index generated through the analysis classified 26.11% of the total study area as critical, 69.53% as fragile, and 2.70% as either prone to or unaffected by degradation processes. According to the ESA index, the areas covered by forests with optimal species composition and high canopy cover were the least susceptible to degradation. The areas under intensive agricultural production without any application of conservation measures were the most susceptible to degradation. Future strategies for optimal land-use patterns are discussed, such as the intergration of woody species in croplands to protect soil against degradation and meet human needs in the areas prone to degradation.

Keywords: Land Degradation, Sensitivity, MEDALUS, Vegetation Cover, Spatial Analysis

iForest 15 (3): 163-170 (2022) - doi: 10.3832/ifor3871-015
https://iforest.sisef.org/contents/?id=ifor3871-015

Research Articles: Chloroplast DNA barcoding genes matK and psbA-trnH are not suitable for species identification and phylogenetic analyses in closely related pines

Olsson S, Giovannelli G, Roig A, Spanu I, Vendramin GG, Fady B — 2022-04-25

Olsson S, Giovannelli G, Roig A, Spanu I, Vendramin GG, Fady B

CHLOROPLAST DNA BARCODING GENES MATK AND PSBA-TRNH ARE NOT SUITABLE FOR SPECIES IDENTIFICATION AND PHYLOGENETIC ANALYSES IN CLOSELY RELATED PINES

Abstract: The largest and most economically important conifer genus Pinus is widespread in the northern hemisphere. Comprehensive phylogenies relying on complete chloroplast gene sequences are now available for the entire genus. However, phylogenetic relationships remain unresolved for certain lineages. One such example, which is also inconsistent in terms of biogeography, is within the subsection Pinus and includes five taxa: Pinus densiflora, P. nigra, P. resinosa, P. sylvestris and P. mugo / uncinata species complex. In this study, we use this clade as an example to explain weak support in phylogenetic studies of closely related pine species and show that some of the most popular genetic markers, namely the chloroplast DNA barcoding sequences matK, psbA- trnH and rbcL, are not recommended for species identification purposes in European pines. In addition, we show that matK and psbA-trnH contain contradicting phylogenetic signals in some of the most economically important pine species.

Keywords: Gene Tree, Taxonomy, Pinus, GenBank

iForest 15 (2): 141-147 (2022) - doi: 10.3832/ifor3913-015
https://iforest.sisef.org/contents/?id=ifor3913-015

Research Articles: Can forest trees take up and transport nanoplastics?

2022-04-09

Murazzi ME, Cherubini P, Brunner I, Kägi R, Saurer M, Ballikaya P, Hagedorn F, Al Sid Cheikh M, Onandia G, Gessler A

CAN FOREST TREES TAKE UP AND TRANSPORT NANOPLASTICS?

Abstract: Plastic contamination of ecosystems has increased dramatically over the last decades, raising concerns about the negative impacts of plastic particles on aquatic and terrestrial systems. In recent years, the focus of most research has shifted from large fragments (macroplastic) to micro- (<5 mm) and more recently to nano-plastic (<1000 nm) particles as more evidence has come to light about their ubiquity in water, soils, and living systems, and their effects on ecosystem and human health. In this study, we investigate nanoplastic uptake in the roots of seedlings (1-2 years old) of three different tree species and assess their transport to different tissues. Parts of the main roots of silver birch (Betula pendula Roth), sessile oak (Quercus petraea Matt. [Liebl.]), and Norway spruce (Picea abies [L.] Karst.) were immersed for one or four days in a suspension containing 13C-labelled nano-sized polystyrene particles (13C-nPS; 99% 13C, d = 28 ± 8 (1 σ) nm). Carbon stable isotope analysis showed significant 13C enrichment (P < 0.05) in the immersed part of the root after one day of treatment in all three species, and after four days in Q. petraea alone. Signals of significant 13C enrichment were also found in the aboveground tissues of the trees. The stem of B. pendula in particular showed a significant 13C enrichment after one day of treatment (P < 0.01). This indicates that nanoplastic particles can be taken up through tree roots into the tree’s central cylinder, where they are subsequently conveyed through the tree by acropetal transport via the xylem.

Keywords: Forest Trees, Nanoplastic, Polystyrene

iForest 15 (2): 128-132 (2022) - doi: 10.3832/ifor4021-015
https://iforest.sisef.org/contents/?id=ifor4021-015

Research Articles: LIFE-CLIVUT, ecosystem benefits of urban green areas: a pilot case study in Perugia (Italy)

2022-04-09

Orlandi F, Fornaciari M, Ranfa A, Proietti C, Ruga L, Meloni G, Burnelli M, Ventura F

LIFE-CLIVUT, ECOSYSTEM BENEFITS OF URBAN GREEN AREAS: A PILOT CASE STUDY IN PERUGIA (ITALY)

Abstract: Trees have a great value in terms of ecosystem services in urban areas. LIFE CLIVUT is an “Information and Governance” European project developed in 4 Mediterranean Cities, with the goal of increasing the knowledge and awareness of citizens, especially young people, on the importance of the presence and good management of urban trees to mitigate the “Heat Island” effects. The data collected on the value of tree heritage and their future potential are used to design a green asset management strategy that will help urban planners adopt better practices for the mitigation of the effects of climate change in urban environments. This paper illustrates the results of tree census activity in four urban green areas of Perugia, Central Italy, that will be compared with those recorded in others cities involved in the project. Dendrometric parameters (diameter at breast height, tree height, first branch height, max and min crown width, crown shape and density) were recorded in situ using a dedicated software operating through a web app (“Clivut-Treedb”). The following ecosystem services were estimated: CO2 sequestration, particulate matter (PM) absorption, shadow effect, biodiversity indexes. Several tree species characterized by important wood structures during their adult phase, such as Pinus pinea, Quercus ilex, Q. pubescens, Ulmus carpinifolia, Populus alba and Aesculus hippocastanum showed the highest estimates of CO2 stored. Q. ilex was the most efficient species in particulate adsorption, showing similar estimates (about 60 g PM10 tree-1 year-1) in the 3 oldest green areas established in the 1980s, while the youngest plantations (dating back to 2005) absorbed about 10 g tree-1 of PM10 per year. In terms of the potential cooling effect of trees, preliminary estimates of the shaded areas highlighted the difference between the older green areas (about 50% of shading) compared to the younger ones (about 15% and 8%).

Keywords: Urban Green Asset, Open Access WebApp, Tree Ecosystem Value, LIFE CLIVUT

iForest 15 (2): 133-140 (2022) - doi: 10.3832/ifor3908-015
https://iforest.sisef.org/contents/?id=ifor3908-015

Review Papers: Tectona grandis Linn. f. secondary metabolites and their bioactive potential: a review

Chávez-Salgado LP, Vandenbossche V, Vilarem G — 2022-03-26

Chávez-Salgado LP, Vandenbossche V, Vilarem G

TECTONA GRANDIS LINN. F. SECONDARY METABOLITES AND THEIR BIOACTIVE POTENTIAL: A REVIEW

Abstract: Tectona grandis Linn. f. (teak) is one of the most appreciated high-quality timber all over the world due to its economic value and wide array of applications. This tropical hardwood presents outstanding characteristics like pleasing aesthetic appearance, strength, lightness, ease of working, dimensional stability, and decay resistance. The latter quality is mainly ascribed to its extractives, which contain biologically active compounds (mainly quinones and anthraquinones) that confer a natural resistance against termites and fungi. This review focuses on teak secondary metabolites and the bioactivity potential of heartwood extractives. Furthermore, it covers the generalities of the teak tree and gives an overview on the approaches aimed to valorize the wastes from woodworking enterprises as a possible source of functional extractives and as an eco-friendly raw material. Notwithstanding the efforts made to elucidate the compounds present in teak wood, further research is needed to understand the chemical bases of its natural resistance to decay. Moreover, there is a lack of economic, technical, and ecotoxicity feasibility studies regarding extractives as a source of bioactive molecules for pharmaceutical, food, or cosmetics purposes.

Keywords: Extractives, Natural Resistance, Bioactivity, Secondary Metabolites, Teak Heartwood

iForest 15 (2): 112-120 (2022) - doi: 10.3832/ifor3714-015
https://iforest.sisef.org/contents/?id=ifor3714-015

Review Papers: Methods of soil seed bank estimation: a literature review proposing further work in Africa

Padonou EA, Akakpo BA, Tchigossou B, Djossa B — 2022-03-26

Padonou EA, Akakpo BA, Tchigossou B, Djossa B

METHODS OF SOIL SEED BANK ESTIMATION: A LITERATURE REVIEW PROPOSING FURTHER WORK IN AFRICA

Abstract: A number of methods are used to assess the soil seed banks of a range of plant species in various habitats around the world, with approaches that differ between countries and continents. An understanding of the differing techniques emphasises the need for further research, especially in Africa. We reviewed 97 articles on soil seed bank estimation, published between 2010 and 2020, and only 13.41% of these were from Africa. Soil sample collection in Africa was based mainly on stratified random sampling, systematic sampling, random sampling or cluster sampling carried out at the end of each region’s rainy season. Random and cluster sampling were more widely used in savannas, while stratified random and systematic samplings were more common in forests. The shape of the samples was either circular or quadrilateral (square and rectangular) or they were measured by soil mass or volume. The soil sampler cores most often applied were: circular diameter of 5 cm; square sizes of 10 × 10 cm, 20 × 20 cm and 25 × 25 cm; and rectangular sizes of 20 × 25 cm and 20 × 10 cm. The most-used soil core depths were 5 cm and 10 cm. No specific sample shape was linked with either forest or savanna ecosystems, although the number of samples depended on the land use and land cover. Soil seed bank densities and species composition were mainly assessed with direct greenhouse germination over trial duration depending on the plant species’ functional traits. In analysing soil seed bank data, non-parametric statistics were more frequently used than parametric statistics because of the skews in the data. This review will contribute to future soil seed bank studies in Africa.

Keywords: Soil Seed Bank, Sampling Methods, Greenhouse Germination, Literature Review

iForest 15 (2): 121-127 (2022) - doi: 10.3832/ifor3850-015
https://iforest.sisef.org/contents/?id=ifor3850-015

Research Articles: Total tree height predictions via parametric and artificial neural network modeling approaches

Karatepe Y, Diamantopoulou MJ, Özçelik R, Sürücü Z — 2022-03-21

Karatepe Y, Diamantopoulou MJ, Özçelik R, Sürücü Z

TOTAL TREE HEIGHT PREDICTIONS VIA PARAMETRIC AND ARTIFICIAL NEURAL NETWORK MODELING APPROACHES

Abstract: Height-diameter relationships are of critical importance in tree and stand volume estimation. Stand description, site quality determination and appropriate forest management decisions originate from reliable stem height predictions. In this work, the predictive performances of height-diameter models developed for Taurus cedar (Cedrus libani A. Rich.) plantations in the Western Mediterranean Region of Turkey were investigated. Parametric modeling methods such as fixed-effects, calibrated fixed-effects, and calibrated mixed-effects were evaluated. Furthermore, in an effort to come up with more reliable stem-height prediction models, artificial neural networks were employed using two different modeling algorithms: the Levenberg-Marquardt and the resilient back-propagation. Considering the prediction behavior of each respective modeling strategy, while using a new validation data set, the mixed-effects model with calibration using 3 trees for each plot appeared to be a reliable alternative to other standard modeling approaches based on evaluation statistics regarding the predictions of tree heights. Regarding the results for the remaining models, the resilient propagation algorithm provided more accurate predictions of tree stem height and thus it is proposed as a reliable alternative to pre-existing modeling methodologies.

Keywords: Tree Height Model Prediction, Generalized Models, Mixed-Effects Models, Levenberg-Marquardt Algorithm, Resilient Propagation

iForest 15 (2): 95-105 (2022) - doi: 10.3832/ifor3990-015
https://iforest.sisef.org/contents/?id=ifor3990-015

Research Articles: The physicomechanical and thermal properties of Algerian Aleppo pine (Pinus halepensis) wood as a component of sandwich panels

Lakreb N, Sen U, Bezzazi B, Pereira H — 2022-03-21

Lakreb N, Sen U, Bezzazi B, Pereira H

THE PHYSICOMECHANICAL AND THERMAL PROPERTIES OF ALGERIAN ALEPPO PINE (PINUS HALEPENSIS) WOOD AS A COMPONENT OF SANDWICH PANELS

Abstract: Aleppo pine (Pinus halepensis Mill.) is the main forest species of Algeria occupying more than 35% of the total forest area of the country. However, the physicomechanical and thermal characteristics of Algerian P. halepensis wood are not well-known. This research investigates the physical (moisture, density, swelling, and shrinkage), mechanical (bending strength and modulus of elasticity), and thermal (mass loss under combustion and pyrolysis as well as thermal conductivity) properties of P. halepensis wood from the Darguina (Bejaia) forest in Algeria. The results showed that Algerian P. halepensis wood with a mean density of 540 kg m-3 has good dimensional stability in swelling and shrinkage, with 116.43 MPa bending strength and a modulus of elasticity of 17,520 MPa. The wood shows a good thermal resistance under low-temperature range and has a thermal conductivity of 0.21 W m-1 K-1. The overall results indicate that Algerian P. halepensis wood may be commercially exploited for construction and insulation applications, namely in the production of sandwich composites.

Keywords: Density, Bending Strength, Thermal Conductivity, Shrinkage, Swell-ing

iForest 15 (2): 106-111 (2022) - doi: 10.3832/ifor3952-015
https://iforest.sisef.org/contents/?id=ifor3952-015

Research Articles: Assessing the performance of MODIS and VIIRS active fire products in the monitoring of wildfires: a case study in Turkey

Coskuner KA — 2022-03-19

Coskuner KA

ASSESSING THE PERFORMANCE OF MODIS AND VIIRS ACTIVE FIRE PRODUCTS IN THE MONITORING OF WILDFIRES: A CASE STUDY IN TURKEY

Abstract: MODIS and VIIRS fire products have been widely used to detect and monitor fire activity at a global scale, as they provide highly relevant information on fire events, on their spatial and seasonal trends. Although these products have some limitations in detecting fires in forested areas due to closed canopy and smoke, they have been widely used to monitor and assess forest fires in many scientific studies. This study analyzes the performance of MODIS (MCD14ML) and VIIRS S-NPP (VNP14IMG) active fire/hotspot products in fire detection in five different land cover types (closed and open forests, shrublands, herbaceous vegetation and croplands) and compares the results to the ground-based fire database from 2015 to end of the 2019 in Turkey. Detected fires with a confidence value above 30% (nominal and high confidence) were used in the study. The land cover was assessed using the European Space Agency (ESA) Copernicus Global Land Service (CGLS) Dynamic Land Cover Layers at 100 m resolution in the study area. The performance assessment of two fire/hotspot products were conducted in three fire size classes, namely: fire size <1 ha, 1 to 10 ha, and >10 ha in five different land cover types. The results indicated that the overall accuracy of MODIS ranged from 0.6% to 16.6% and VIIRS S-NPP ranged from 1.3% to 25.6% of all ground-based fires in five different land cover types. The detection rates increased as the fire size increased. This study indicates that some limitations still exist to use MODIS and VIIRS S-NPP active fire/hotspot data in the assessment of wildfires.

Keywords: Wildfires, Fire Monitoring, Land Cover, MODIS, VIIRS, Remote Sensing

iForest 15 (2): 85-94 (2022) - doi: 10.3832/ifor3754-015
https://iforest.sisef.org/contents/?id=ifor3754-015

Research Articles: Influence of site conditions and land management on Quercus suber L. population dynamics in the southern Iberian Peninsula

2022-03-14

Jurado Doña V, López-Jurado J, González Román A, Sánchez-Salguero R, Matías L, Díaz Del Olmo F

INFLUENCE OF SITE CONDITIONS AND LAND MANAGEMENT ON QUERCUS SUBER L. POPULATION DYNAMICS IN THE SOUTHERN IBERIAN PENINSULA

Abstract: During recent decades, tree mortality and dieback have been reported in forest ecosystems across global biomes. Although numerous forest species, including those of the genus Quercus, have been affected by hotter and drier conditions in the Mediterranean Basin during the last decades, there is scarce information regarding the interactive role of past management and climate across large areas of south-western Europe. Here, we examined the influence of several climatic factors (mean annual temperature, annual precipitation) over the last 3 decades, latitude, land management and site conditions on the cork oak (Quercus suber L.) population dynamics given their high ecological and economic relevance. We sampled 20 plots across contrasting environmental conditions in SW Iberian Peninsula with different land property (public vs. private) to characterize cork oak tree size, stand density, mortality ratio and regeneration. We observed widespread effects of latitude (8.9% at northern vs. 15.6% at southern plots) and land property (6.9% in private properties vs. 13.9% in public ones) on tree mortality. Tree density and basal area differed with latitude, with higher values (307.2 trees ha-1 and 38.4 m2 ha-1, respectively) at northern populations. In addition, the more intense cork-focused productive management resulted in higher tree sizes in private (mean DBH = 47.3 cm) than in public (mean DBH = 37.8 cm) plots. Tree regeneration was higher in northern forests (94.9 ± 25.2 vs. 26.0 ± 6.1 saplings ha-1 for the southern location), being this difference more pronounced in public plots. These findings highlight the importance of sustainable forest management in public and private forests for further reduction of mortality processes, as well as for enhancing the regeneration aimed to the conservation of cork oak under forecasted drier conditions of these economically invaluable Mediterranean forests.

Keywords: Cork Oak, Climate Change, Forest Management, Mediterranean, Land Uses, Tree Mortality

iForest 15 (2): 77-84 (2022) - doi: 10.3832/ifor3753-015
https://iforest.sisef.org/contents/?id=ifor3753-015

Research Articles: Red wood ants shape epiphytic lichen assemblages in montane silver fir forests

2022-02-22

Di Nuzzo L, Masoni A, Frizzi F, Bianchi E, Castellani MB, Balzani P, Morandi F, Sozzi Y, Vallese C, Santini G, Benesperi R

RED WOOD ANTS SHAPE EPIPHYTIC LICHEN ASSEMBLAGES IN MONTANE SILVER FIR FORESTS

Abstract: The Formica rufa group comprises several ant species which are collectively referred to as “red wood ants” (hereafter RWA). These species have key roles in forest ecosystems, where they are ecologically dominant and greatly influence the dynamics of the habitat they colonise. Various studies have shown how their trophic activity may affect other organisms, which include both other invertebrates and plants. We can therefore hypothesize that their presence could affect the taxonomic and functional composition of epiphytes, despite clear information on such an effect is lacking. This study aimed to fill this research gap by evaluating whether the presence of red wood ants could affect the structure and composition of lichen communities. We selected two sites on the Apennine Mountains in Italy, where the red wood ant F. paralugubris was introduced from the Alps more than 50 years ago. In each site, lichen assemblages on Abies alba trees located within the colonised areas were compared to those from nearby, non-occupied areas. The results allowed for the identification of significant effects of F. paralugubris on the structure of lichen communities. Although there was no detectable impact on lichen species richness, a significant difference in their community composition between colonised and control sites was detected. Furthermore, ant presence seemed to be associated with specific lichen functional traits such as asexual reproduction. We argue that RWA could affect the lichen community either directly, e.g., by actively dispersing the species capable of asexual reproduction through their movements on trees (ant-mediated dispersion), or indirectly through herbivore exclusion. Finally, we also observed differences in β-diversity among the colonised and non-colonised sites.

Keywords: Formica paralugubris, Red Wood Ants, Lichen Diversity, Impact, Introduced Species, Functional Diversity

iForest 15 (1): 71-76 (2022) - doi: 10.3832/ifor3897-014
https://iforest.sisef.org/contents/?id=ifor3897-014

Research Articles: Modeling the risk of illegal forest activity and its distribution in the southeastern region of the Sierra Madre Mountain Range, Philippines

Barit JB, Choi K, Ko DW — 2022-02-21

Barit JB, Choi K, Ko DW

MODELING THE RISK OF ILLEGAL FOREST ACTIVITY AND ITS DISTRIBUTION IN THE SOUTHEASTERN REGION OF THE SIERRA MADRE MOUNTAIN RANGE, PHILIPPINES

Abstract: Illegal activity within protected forests, such as illegal logging, slash-and-burn farming, and agricultural expansion, has brought many plant and animal species to the brink of extinction and threatens various conservation efforts. The Philippine government has introduced a number of actions to combat environmental degradation, including the use of mobile platforms such as the SMART-Lawin system to collect patrol data from the field, which represents a remarkable step towards data-driven conservation management. However, it remains difficult to control illegal forest activity within protected landscapes due to limited patrol and law enforcement resources. A better understanding of the spatial distribution of illegal activity is crucial to strengthening and efficiently implementing forest protection practices. In the present study, we predicted the spatial distribution of illegal activity and identified the associated environmental factors using maximum entropy modeling (MaxEnt). Patrol data collected using the SMART-Lawin system from the Baliuag Conservation Area for the period 2017-2019 were used to train and validate the MaxEnt models. We tuned the MaxEnt parameter setting using the ENMeval package in R to overcome sampling bias, avoid overfitting, and balance model complexity. The resulting MaxEnt models provided a clear understanding of the overall risk of illegal activity and its spatial distribution within the conservation area. This study demonstrated the potential utility of data-driven models developed from patrol observation records. The output of this research is beneficial for conservation managers who are required to allocate limited resources and make informed management decisions.

Keywords: Philippines, SMART, Ranger Patrol Data, Illegal Forest Activity, Protected Area Management

iForest 15 (1): 63-70 (2022) - doi: 10.3832/ifor3937-014
https://iforest.sisef.org/contents/?id=ifor3937-014

Research Articles: Universal reaction norms for the sustainable cultivation of hybrid poplar clones under climate change in Italy

2022-02-08

Marchi M, Bergante S, Ray D, Barbetti R, Facciotto G, Chiarabaglio PM, Hynynen J, Nervo G

UNIVERSAL REACTION NORMS FOR THE SUSTAINABLE CULTIVATION OF HYBRID POPLAR CLONES UNDER CLIMATE CHANGE IN ITALY

Abstract: The cultivation of hybrid poplar clones is increasing worldwide. Hundreds of hectares of plantations now occur across Europe and other continents such as North America, using tested clones and novel genotypes. Research effort aims are to develop fast growing disease- and pest-resistant clones to improve production quality and quantity. In this study the phenotypic plasticity of poplar clones was tested across environmental and temporal gradients. The growth performance of 49 hybrid poplar clones recorded between 1980 and 2021 was analysed using a mixed-effects model with climatic data as a predictor variable. Clones were aggregated into two groups according to their breeding protocol (i.e., standard clone, and improved material) and their growth modelled for future climate scenarios of RCPs 2.6 and 8.5 using a downscaled version of the variants 01 and 21 of UKCP18 climate projections dataset for three 30-year normal period time-slices: 2030s, 2040s, 2050s. The fitted growth models showed highly significant results, explaining more than 85% of the variance, with a mean relative absolute error of approximately 2%. Improved material showed more resistance to warmer and drier climates and less sensitivity to the changing climate. While no unique pattern was found when comparing growth performances, new improved clones were more productive than older clones (e.g., “I-214”) with an additional benefit of resistance to rust and pests. Spatial predictions confirmed the Po valley as the most important geographic area for poplar cultivation in Italy, but zones in Central and Southern Italy show potential. However, the Po Valley is also where poplars are predicted to be suitable in the next decades with large uncertainties. The analysis identified the need for more research on the topic of poplar breeding. For example, models using the most extreme (warm and dry) climate projection, variant 01 of RCP8.5 of the UKCP18, exceeded the historic climate threshold, and predictions used model extrapolation, with associated statistical uncertainty. Therefore, predictions should be considered with care and more research effort is required to test clones over wider environmental conditions.

Keywords: Forest Tree Breeding, ClimateDT, Universal Response Function, B4EST

iForest 15 (1): 47-55 (2022) - doi: 10.3832/ifor3989-015
https://iforest.sisef.org/contents/?id=ifor3989-015

Research Articles: Comparison of extractive chemical signatures among branch, knot and bark wood fractions from forestry and agroforestry walnut trees (Juglans regia × J. nigra) by NIR spectroscopy and LC-MS analyses

2022-02-08

Heim L, Dodeler R, Brancheriau L, Marchal R, Boutahar N, Lotte S, Dumarçay S, Gérardin P, Candelier K

COMPARISON OF EXTRACTIVE CHEMICAL SIGNATURES AMONG BRANCH, KNOT AND BARK WOOD FRACTIONS FROM FORESTRY AND AGROFORESTRY WALNUT TREES (JUGLANS REGIA × J. NIGRA) BY NIR SPECTROSCOPY AND LC-MS ANALYSES

Abstract: Walnut agroforestry systems require regular tree pruning, generating a large volume of biomass residues which are mainly valorized as wood-energy, Ramial Chipped Wood (RCW) or animal litter. However, walnut is recognized as a rich source of different chemical compounds, which could be recovered as valuable chemicals. This study aims to improve the knowledge on the composition of the water and ethanol extractive contents of wood, knot and bark fractions from walnut branches, harvested in agroforestry (AF) and traditional forestry control (FC) systems. LC-MS analyses were carried out to identify the chemical composition of extracts. Additionally, all samples were analyzed by near-infrared (NIR) spectroscopy with the aim of developing a fast tool to distinguish walnut branches, knots and bark wood fractions from trees grown under agroforestry and plantation management. Extractive contents and chemical composition of AF and FC wood samples were slightly different among branch, knot and bark. Despite these small chemical differences, PLS-DA models based on NIRS measurements can distinguishing among wood samples from walnut trees grown under different silvicultural regimes. In addition, in the both forestry systems, branch and knot extractive contents were significantly lower than those of bark specimens. Principal Component Analyses (PCA) based on NIR-spectrometry of raw samples revealed that the chemical composition of branch and knot woods are similar to each other and are very different compared to those of bark samples. This study provides new knowledge on branch woods from agroforestry systems, which are still very under-studied at present.

Keywords: Agroforestry, Bark, Branches, Extractives, Knot, Walnut

iForest 15 (1): 56-62 (2022) - doi: 10.3832/ifor3973-014
https://iforest.sisef.org/contents/?id=ifor3973-014

Research Articles: Secondary metabolites of six Siberian and Crimean Armillaria species and their in vitro phytotoxicity to pine, larch and poplar

2022-02-04

Antipova TV, Zhelifonova VP, Litovka YA, Pavlov IN, Baskunov BP, Kokh ZA, Makolova PV, Timofeev AA, Kozlovsky AG

SECONDARY METABOLITES OF SIX SIBERIAN AND CRIMEAN ARMILLARIA SPECIES AND THEIR IN VITRO PHYTOTOXICITY TO PINE, LARCH AND POPLAR

Abstract: Basidiomycetes Armillaria infect deciduous, coniferous and fruit trees, causing enormous economic damage. The role of secondary metabolites (tricyclic sesquiterpene aryl esters - melleolides) in the life cycle and pathogenesis of Armillaria is under active investigation. To date, not all species of Armillaria have been tested for the biosynthesis of melleolides. We investigated the secondary metabolite profiles of six root-pathogenic species of the genus Armillaria (A. borealis Marxmüller & Korhonen, A. cepistipes Velenovský, A. gallica Marxm, A. mellea (Vahl) P. Kummer, A. sinapina Bérubé & Dessur, A. ostoyae (Romagn.) Herink) distributed in Siberia (South Krasnoyarsk Krai, Republic of Tyva, Republic of Khakassia, Taimyr Peninsula), Russian Far East (Sikhote-Alin) and Crimea (Krymsky National Park, Chatyr-Dag Mountain Lower Plateau). A total of 15 compounds were identified in the metabolome profile. Two compounds (melleolide D and melledonal C) are synthesized by all investigated strains irrespective of their geographic location and host plant. The maximum spectrum of melleolides (7-8 compounds) was found in isolates of A. borealis, A. gallica, A. sinapina, A. ostoyae. In submerged culture, the maximum accumulation of melleolides varied from 2 up to 239 mg l-1. A mixture of melleolide D and melledonal C (1:1) synthesized by the most productive strain A. mellea Cr2-17 was first found to have a phytotoxic action on the growth parameters of the callus culture Populus balsamifera and 10-day-old conifer seedlings. A 0.5% concentration of melleolides caused a credible decrease of P. balsamifera callus raw biomass; a decrease of the viability of Larix sibirica and, which is especially significant, Pinus sylvestris seedlings; inhibition of stem and root growth processes; dechromation of foliage; loss of turgor. The occurrence of a broad range of melleolides in the metabolome profile and two common compounds in all investigated strains, with a phytotoxic action at their sufficiently high concentration, enables considering the synthesis of melleolides by Armillaria fungi as one of the possible mechanisms of their pathogenicity efficiently realized in strains characterized by overproduction of melleolides under natural conditions.

Keywords: Melleolides, Metabolome, Armillaria fungi, Phytotoxicity, Callus, Coniferous Plants

iForest 15 (1): 38-46 (2022) - doi: 10.3832/ifor3840-014
https://iforest.sisef.org/contents/?id=ifor3840-014

Technical Notes: The impact of pruning on tree development in poplar Populus × canadensis “I-214” plantations

Danilović M, Sarić R, Cirović V, Pudja V — 2022-01-30

Danilović M, Sarić R, Cirović V, Pudja V

THE IMPACT OF PRUNING ON TREE DEVELOPMENT IN POPLAR POPULUS × CANADENSIS “I-214” PLANTATIONS

Abstract: The effect of pruning on tree development and the potential structure of wood assortments was investigated in the poplar Populus × canadensis clone “I-214”. The study was carried out in a permanent sample plot within a poplar plantation established in 2006, in the area of the “Vojvodinašume” Public Company, within the “Gornje Potamišje” Forest Management Unit (Republic of Serbia). Pruning was performed on a total of 325 trees at different stem heights and a total of 13,186 branches were pruned. The average number of pruned branches per tree at the stem height of 5 m was 36, while it was 40 at the stem height of 6 m and 46 at the stem height of 7 m. The average diameter of pruned branches was 1.7 cm. The results showed that there are no significant differences in diameters at breast height between pruned and unpruned trees after two different intensities of pruning. Our results showed that pruning do not impact the long-term growth performance in poplar clone “I-214”, while remarkably improving the quality and economic value of wood assortments obtained from pruned trees.

Keywords: Poplar, Pruning, Pruning Intensity, Pruning Height, Branch Diameter

iForest 15 (1): 33-37 (2022) - doi: 10.3832/ifor3865-014
https://iforest.sisef.org/contents/?id=ifor3865-014

Research Articles: Quantifying the vertical microclimate profile within a tropical seasonal rainforest, based on both ground- and canopy-referenced approaches

Deng Y, Dong J, Zhang W, Yuan S, Tan Z, Song Q, Deng X, Cao M — 2022-01-27

Deng Y, Dong J, Zhang W, Yuan S, Tan Z, Song Q, Deng X, Cao M

QUANTIFYING THE VERTICAL MICROCLIMATE PROFILE WITHIN A TROPICAL SEASONAL RAINFOREST, BASED ON BOTH GROUND- AND CANOPY-REFERENCED APPROACHES

Abstract: Quantifying the microclimate of a tall and complex tropical forest is quite challenging because of the difficulty in accessing the canopy. Traditional ground-referenced methods may underestimate the contribution of canopy heterogeneity to structuring the vertical profiles of forest microclimate. The present study examined how the reference height affects vertical variation of microclimate in a tropical rainforest in southwest China, based on both ground- and canopy-referenced approaches. The results show that the canopy-referenced approach yielded a higher model fit than did the ground-referenced method, and only canopy-referenced method could detect two thresholds in the leaf area index at approximately -22.6 ± 2.7 m and -36.6 ± 6.6 m below the canopy top; the higher threshold is consistent with thresholds of the annual mean temperature, the diurnal ranges of air temperature, and the relative humidity in the vertical profile; while the lower threshold is similar with the breakpoints of annual mean relative humidity, the annual ranges of air temperature and the relative humidity along the profile. The discontinuous variance in the microclimatic factors was due to the canopy structure in the vertical profile. Selecting the top of the canopy as the reference height could be a better approach for quantifying the microclimatic profiles in the studied forest, and this approach can improve our understanding of the effects of the vertical stratification of microclimates on species composition and diversity in this forest.

Keywords: Tropical Seasonal Rainforest, Vertical Gradient, Light Environment, Temperature And Humidity, Distance From The Canopy Surface

iForest 15 (1): 24-32 (2022) - doi: 10.3832/ifor3780-014
https://iforest.sisef.org/contents/?id=ifor3780-014

Research Articles: Nursery fertilization affected field performance and nutrient resorption of Populus tomentosa Carr. ploidy levels

Wang M, Li G, Liu Y — 2022-01-24

Wang M, Li G, Liu Y

NURSERY FERTILIZATION AFFECTED FIELD PERFORMANCE AND NUTRIENT RESORPTION OF POPULUS TOMENTOSA CARR. PLOIDY LEVELS

Abstract: Nutrient resorption (NuR) is an important nutrient conservative strategy but little information is available about the effect of nursery fertilization on NuR in the field. In this study, diploid and triploid one-year-old plants of Populus tomentosa Carr. were fertilized with 9 g N per plant, and non-fertilized plants as control. Initial functional attributes, i.e., height, diameter, stem mass, mineral nutrients and non-structural carbohydrate (NSC) levels of each tissue, were measured before planting. Field performance (survival, total height, diameter, stem volume and their growth, leaf nutrient status, and NuR) were measured in the field. Compared to control, 9 g N per plant was benefit for plant growth, mineral nutrients and NSC accumulation of diploids, but declined plant size of triploids before planting. While in the field, fertilization effect on plant size was inversed for each ploidy level. Nursery fertilization increased nitrogen resorption efficiency (NRE) of triploids and decreased phosphorus resorption efficiency (PRE) of both ploidy levels. Initial plant size were the most effective parameters predicting field performance and NuR. Furthermore, NRE was multi-elements controlled as indicated by the correlation of N and P in green and senesced leaves, while PRE was only positively correlated with P in green leaves. However, there was no relationship between field growth and NuR. This study deepened our understanding of NuR from the perspective of artificial managements, for instance nursery fertilization.

Keywords: Nursery Fertilization, Nutrient Resorption, Leaf Nutrient Status, Plant Growth, Initial Functional Attributes, Ploidy Levels

iForest 15 (1): 16-23 (2022) - doi: 10.3832/ifor3912-014
https://iforest.sisef.org/contents/?id=ifor3912-014

Research Articles: Deriving tree growth models from stand models based on the self-thinning rule of Chinese fir plantations

Zhang X, Cao QV, Qu Y, Zhang J — 2022-01-13

Zhang X, Cao QV, Qu Y, Zhang J

DERIVING TREE GROWTH MODELS FROM STAND MODELS BASED ON THE SELF-THINNING RULE OF CHINESE FIR PLANTATIONS

Abstract: Self-thinning due to density-dependent mortality usually occurs during the forest development. To improve predictions of such processes during forest successions under climate change, reliable stand-level models are needed. In this study, we developed an integrated system of tree- and stand-level models by deriving tree diameter and survival models from stand growth and survival models based on climate-sensitive self-thinning rule of Chinese fir plantations in subtropical China. The resulting integrated system, having a unified mathematical structure, should provide consistent estimates at both tree and stand levels. Predictions were reasonable at both stand and tree levels. Because stand-level values aggregated from the tree model outputs are different from those predicted directly from the stand models, the disaggregation approach was applied to provide numerical consistency between models of different resolutions. Compared to the unadjusted approach, predictions from the disaggregation approach were slightly worse for tree survival but slightly better for tree diameter. Because the stand models were developed under the climate-sensitive self-thinning trajectory, the integrated system could offer reasonable predictions that could aid in managing Chinese fir plantations under climate change.

Keywords: Chinese Fir, Self-thinning Rule, Disaggregation, Stand Model, Tree Model

iForest 15 (1): 1-7 (2022) - doi: 10.3832/ifor3792-014
https://iforest.sisef.org/contents/?id=ifor3792-014

Research Articles: Contribution of legume and non-legume trees to litter dynamics and C-N-P inputs in a secondary seasonally dry tropical forest

Neves NM, Paula RR, Araujo EA, Gorsani RG, Abreu KMPD, Kunz SH — 2022-01-13

Neves NM, Paula RR, Araujo EA, Gorsani RG, Abreu KMPD, Kunz SH

CONTRIBUTION OF LEGUME AND NON-LEGUME TREES TO LITTER DYNAMICS AND C-N-P INPUTS IN A SECONDARY SEASONALLY DRY TROPICAL FOREST

Abstract: Many studies have investigated nutrient cycling in seasonally dry tropical forests, but few have assessed the contribution of different functional groups to these processes. Here, we investigated general litter dynamics patterns and the contribution of legume and non-legume trees to litter dynamics and carbon (C), nitrogen (N), and phosphorus (P) inputs in a fragment of secondary seasonally dry tropical forest after half a century of forest succession in the Atlantic Forest biome in Brazil. Between 2016 and 2017, we quantified litterfall production, canopy cover, forest floor, and soil C and N storage in 11 permanent plots distributed in the fragment. Vegetation identity and structure had been previously assessed. We quantified the seasonal inputs of leaf litter and C, N, and P separately for each functional group (legume and non-legume tree species). We also analyzed the correlations between the variables measured for each functional group with the variables measured at the plot level. Litter dynamics and nutrient input were affected by climate and functional group. Litterfall production during the two driest months was three times higher than during the other periods of the year, suggesting that species synchronicity is likely to minimize drought-related damage on trees. Legume trees had twice the basal area attained by non-legume trees, but while legumes were larger, non-legumes were more abundant and dominant in the smaller diameter class. Legumes deposited twice as much N during the driest period of the year as non-legumes. Although leaf litter, C, and P inputs by legumes were generally higher than those of non-legumes, these differences during the dry season were not statistically significant. We also found that the legume variables correlated better with the plot-level variables, compared to the non-legume functional group. Our results also indicated potential effects of the leaf litter and nutrient inputs by the legume functional group on the decomposition constant and, consequently, on the time of forest floor decomposition. Further studies should assess the role of different functional groups in litter dynamics and nutrient inputs in seasonally dry tropical forests.

Keywords: Nutrient Cycling, Litterfall, Nutrient Input, Canopy Cover, Decomposition Rate, Fabaceae, Atlantic Forest

iForest 15 (1): 8-15 (2022) - doi: 10.3832/ifor3442-014
https://iforest.sisef.org/contents/?id=ifor3442-014

Research Articles: Kretzschmaria deusta, a limiting factor for survival and safety of veteran beech trees in Trentino (Alps, Northern Italy)

2021-12-18

Cordin G, Messina G, Maresi G, Zottele F, Ferretti F, Montecchio L, Oliveira Longa CM

KRETZSCHMARIA DEUSTA, A LIMITING FACTOR FOR SURVIVAL AND SAFETY OF VETERAN BEECH TREES IN TRENTINO (ALPS, NORTHERN ITALY)

Abstract: The importance of veteran trees is well recognised nowadays. The sudden breakage of some of these plants in Trentino (Italy), mainly due to Kretzschmaria deusta, prompted a survey of the veteran beeches reported in this area. Visual tree assessment was carried out in 40 sites with either single trees or groups of beeches, for a total of 115 trees evaluated. Most trees showed serious defects or problems in need of management and 19 had a high level of risk of breakage because of the presence of several structural problems. The presence of K. deusta was recorded on 50.4% of the examined trees. The pathogen was also identified in the proximity of investigated trees at 29 sites. Laboratory tests confirmed the identity of K. deusta by microbiological and molecular approaches and also identified Cosmopora berkeleyana as mycoparasite on K. deusta fruiting bodies. Isolates obtained from declining trees and old stumps showed the same pattern of growth at different temperatures. The risk evaluation emphasised how the fungus could affect the survival and safety of these veteran trees; this was confirmed by the collapse of four of the investigated trees in the last years. Therefore, K. deusta, which has been considered as a facultative parasite up to now, could play a more incisive role both in the decline of old beech trees and the natural evolution of aging beech woods.

Keywords: Fagus sylvatica, Xilariaceae, Brittle Cinder, Soft-rot, Visual Tree Assessment, Veteran Tree Conservation

iForest 14 (6): 576-581 (2021) - doi: 10.3832/ifor3830-014
https://iforest.sisef.org/contents/?id=ifor3830-014

Research Articles: Composted sewage sludge as an alternative substrate for forest seedlings production

2021-12-16

Gabira MM, Silva RBGD, Bortolheiro FPDAP, Mateus CDMD, Villas Boas RL, Rossi S, Girona MM, Silva MRD

COMPOSTED SEWAGE SLUDGE AS AN ALTERNATIVE SUBSTRATE FOR FOREST SEEDLINGS PRODUCTION

Abstract: The production of forest seedlings with adequate morphological and physiological characteristics is essential for the success of plantations. Substrates and irrigation are the major factors determining seedlings’ growth. Substrates made of urban and agricultural residues are a sustainable alternative to peat-based substrates. In this study, we evaluated how composted sewage sludge substrates affect the growth and gas exchange in seedlings of Cedrela fissilis Vell. Seedlings were produced under daily irrigation depths of 6, 9, and 12 mm, and on different substrates. The substrates were based on sewage sludge composted with Eucalyptus bark or sugarcane bagasse, and a commercial substrate based on peat, involving a double factorial design with 12 treatments (3 irrigation depths × 3 substrates). Both physical and chemical characteristics of substrates were analyzed, and morphological traits and gas exchanges of seedlings were measured. Sewage sludge-based substrates presented different characteristics according to the material it was mixed. Eucalyptus bark provided higher bulk density (0.19 g cm-3) and lower total porosity (75%) to the substrate, while sugarcane bagasse increased macroporosity up to 60%. Seedlings produced in sewage sludge-based substrates presented a height up to 17.8 cm and stem diameters of between 8.39-10.29 mm. Higher shoot and root dry mass was obtained in sewage sludge-based substrates with irrigation depth of 9 mm, which were 3.71 and 2.01 g, respectively. Photosynthetic carbon assimilation varied between 2.26 and 3.23 µmol CO2 m-2 s-1, and water use efficiency varied from 2.058 to 3.395 µmol CO2 (mol H2O)-1, with the highest values being obtained in seedlings produced in sewage sludge-based substrates with irrigation depth of 6 mm. Our results demonstrate that sewage sludge-based substrates are an efficient alternative to commercial peat-based substrates for seedling production.

Keywords: Agricultural Residues, Cedrela fissilis, Forest Nursery, Gas Exchange, Irrigation, Plant Growth, Silviculture, Solid Wastes

iForest 14 (6): 569-575 (2021) - doi: 10.3832/ifor3929-014
https://iforest.sisef.org/contents/?id=ifor3929-014

Research Articles: Adaptability and interspecific variability in growth and leaf traits of eucalypt

Makouanzi Ekomono CG, Loubassou CBSV, Mbama MP, Loubota Panzou GJ, Vigneron P — 2021-12-09

Makouanzi Ekomono CG, Loubassou CBSV, Mbama MP, Loubota Panzou GJ, Vigneron P

ADAPTABILITY AND INTERSPECIFIC VARIABILITY IN GROWTH AND LEAF TRAITS OF EUCALYPT

Abstract: Effective adaptability of plants to new environments can be analysed in terms of survival rate. Analysing the traits that favour adaptation to environmental changes provides a more in-depth understanding of the mechanisms involved. Local adaptation occurs because different environmental factors exert selective pressure across habitats. Understanding the leaf mechanisms underlying plant survival and growth is crucial to determine why local adaptation involves trade-offs. A comparative provenance test on 29 eucalyptus species was conducted to improve our understanding of species adaptation strategies on coastal plains of Pointe-Noire, Republic of the Congo. We studied the different functional traits to determine how plants function and to highlight the different species’ adaptive strategies. For each species, survival, growth traits and leaf traits were measured, and the climatic factors of the origin area for each species was taken into account. Cluster analysis was performed on groups of species with a similar growth strategy. The results revealed general trends that explain the physiological mechanisms involved in the species’ local adaptation. Indeed, species have survived to current environmental changes by adjusting their specific leaf area plasticity. The 32 provenances of eucalyptus were subdivided into four groups by cluster analysis. The first cluster included two species (E. pilularis and E. peltata) that are totally unsuited to the local conditions in Pointe-Noire, with the slowest growth rate and smallest specific leaf area. The second cluster contained species that showed a wide variety of growing strategies, allowing them to adapt to local conditions. The third cluster included a species that is specialised in obtaining large quantities of resources, while investing very little in growth. The fourth cluster included species that acquired and used resources at a slow rate. Leaf anatomy was quite responsive to climatic conditions. We evaluated the different strategies and found that eucalyptus species had very diverse functional traits, which may explain their broad ecological range.

Keywords: Adaptability, Eucalyptus, Foliar Traits, Growth Strategies, Clustering Analysis

iForest 14 (6): 560-568 (2021) - doi: 10.3832/ifor3660-014
https://iforest.sisef.org/contents/?id=ifor3660-014

Research Articles: Historical fire ecology and its effect on vegetation dynamics of the Lagunas de Montebello National Park, Chiapas, México

2021-12-01

Ponce-Calderón LP, Rodríguez-Trejo DA, Villanueva-Díaz J, Bilbao BA, Álvarez-Gordillo GDC, Vera-Cortés G

HISTORICAL FIRE ECOLOGY AND ITS EFFECT ON VEGETATION DYNAMICS OF THE LAGUNAS DE MONTEBELLO NATIONAL PARK, CHIAPAS, MÉXICO

Abstract: Historical information on wildfires and dendrochronological studies offer meaningful clues about fire and climate regimes, factors that affect forest structure and dynamics. This study aimed to determine the effect of fire history on vegetation dynamics and successional pathways of areas under different fire management policies in the Lagunas de Montebello National Park (LMNP), Chiapas, México. The selected study sites were El Parque area under fire exclusion policies since 1961; Tziscao-inhabited area under fire prohibition since 1984; and Antelá area with a traditional agricultural fire management history. A Pinus oocarpa ring-width chronology was used as a proxy for climate variability to which wildfire occurrence was mapped and to determine the establishment patterns of this dominant species. Current vegetation composition and structure and fuel loads were determined to characterise the study sites. Large wildfires, like those occurring in 1984 and 1998, were associated with periods of high humidity followed by intense droughts; they were linked to strong El Niño events and severely impacted the LMNP. Vegetation dynamics indicated simplification of mesophyll forest (climax) to pine-oak-sweetgum forests, with Pinus dominating the overstorey in all sampling sites. Pine, oak and sweetgum species were the dominant juvenile trees in Antelá, El Parque and Tziscao, respectively. Late-successional seedlings (i.e., Prunus) were present in Antelá and El Parque, while were absent from Tziscao where several wildfires had occurred. Fuel accumulation in sites within protected areas subject to fire exclusion policies was very high (40-68 t ha-1); in contrast, it was the lowest in rural Antelá (24 t ha-1). Considering vegetation vulnerability to wildfires associated with extreme humid-dry climate events, increased fire hazard due to fuel accumulation, and the socio-ecological impacts of these events, we recommend revising the fire exclusion policies currently implemented in the LMNP and applying an integrated fire management approach that incorporates local socio-ecological conditions.

Keywords: Historical Ecology, Dendrochronology, Fire Ecology, Ecological Succession, Fuel Loads

iForest 14 (6): 548-559 (2021) - doi: 10.3832/ifor3682-014
https://iforest.sisef.org/contents/?id=ifor3682-014

Research Articles: Ectomycorrhizal fungal community in mature white poplar plantation

Milović M, Orlović S, Grebenc T, Bajc M, Kovačević B, Kraigher H — 2021-11-26

Milović M, Orlović S, Grebenc T, Bajc M, Kovačević B, Kraigher H

ECTOMYCORRHIZAL FUNGAL COMMUNITY IN MATURE WHITE POPLAR PLANTATION

Abstract: Ectomycorrhizal communities are rarely studied on seasonal basis, especially in poplar plantations. In this study we analysed the ectomycorrhizal community in a mature twenty-year-old white poplar (Populus alba L.) plantation during four consecutive seasons. Using morpho-anatomical and molecular identification 30 taxa of ectomycorrhizal fungi were recorded of which 15 were identified to the species level, 12 to the genus level, 2 to the family, and one morphotype of ectomycorrhizae remained unidentified. The most abundant among identified ectomycorrhizal fungi were: Inocybe griseovelata, Inocybe splendens, Tuber rufum, and Tomentella sp. 2, which together represented up to 50% of all ectomycorrhizal root tips. The number of ectomycorrhizal fungal taxa and the percentage of vital ectomycorrhizal root tips were highest in winter and spring, respectively. The diversity indices of ectomycorrhizae, number of vital ectomycorrhizal root tips, and total fine roots in the studied poplar plantation did not differ between seasons. Ectomycorrhizal fungi belonging to Inocybaceae family and the short-distance exploration strategy were dominant in all four seasons. On the other hand, the abundance of ectomycorrhizal root tips belonging to the medium-distance exploration strategy type was significantly higher in spring in comparison with autumn and winter.

Keywords: Populus alba L., Ectomycorrhizal Diversity, Morpho-anatomical Characterization, Molecular Identification, Seasons

iForest 14 (6): 540-547 (2021) - doi: 10.3832/ifor3827-014
https://iforest.sisef.org/contents/?id=ifor3827-014

Research Articles: Local adaptation at a small geographic scale observed in Juniperus excelsa populations in southern Turkey

Yücedag C, Çiçek N, Gailing O — 2021-11-24

Yücedag C, Çiçek N, Gailing O

LOCAL ADAPTATION AT A SMALL GEOGRAPHIC SCALE OBSERVED IN JUNIPERUS EXCELSA POPULATIONS IN SOUTHERN TURKEY

Abstract: Juniperus excelsa is one of the most common tree species and has a wide geographical and altitudinal distribution in Turkey. It is also resistant to drought and frost damages and can cope with poor soils. In this study, we explore whether there are any differences among eight J. excelsa populations from a narrow geographic region grown in a common garden test site in terms of growth and contents of photosynthetic pigments, proline and nutrients of their 10-year-old saplings. Phenotypic trait differentiation (QST) at all traits, FST at neutral SSRs among six of the populations and associations of traits with environmental conditions at provenance regions were also analysed to test for patterns of local adaptation. Sapling traits of eight J. excelsa populations of from Lakes District in Turkey at the test site showed that populations significantly differed for growth, photosynthetic pigments, proline and nutrient contents. The mean height and diameter of 10-year-old saplings were found as 94.5 cm and 41.6 mm, respectively. EÄŸirdir-Barla and Sütçüler-Tota populations showed the highest performance for the majority of traits at age 10 compared to all other populations. Nutrient contents in leaves were generally in the sufficiency range reported for plant growth. Considering photosynthetic pigments and proline, it could be concluded that the populations were not exposed to severe stress. Among the environmental variables, the best predictors of growth were annual mean minimum temperature and soil texture at the populations’ origin, accounting for 49% of the variation in height and diameter, respectively. Also, higher phenotypic trait differentiation for most traits than genetic differentiation at neutral genetic markers suggests local adaptation at a small geographic scale. The present study revealed adaptive divergence between populations at a small geographic scale. However, environmental similarity between region of origin and test site was not a good indicator of growth-related traits. The results can be used in the early selection of provenances for J. excelsa for plantation establishment.

Keywords: Juniperus excelsa, Chlorophyll, Proline, Phenotypic Trait Differentiation, Local Adaptation

iForest 14 (6): 531-539 (2021) - doi: 10.3832/ifor3769-014
https://iforest.sisef.org/contents/?id=ifor3769-014

Research Articles: Towards a functional phytosociology: the functional ecology of woody diagnostic species and their vegetation classes in Northern Italy

Zanzottera M, Dalle Fratte M, Caccianiga M, Pierce S, Cerabolini BEL — 2021-11-22

Zanzottera M, Dalle Fratte M, Caccianiga M, Pierce S, Cerabolini BEL

TOWARDS A FUNCTIONAL PHYTOSOCIOLOGY: THE FUNCTIONAL ECOLOGY OF WOODY DIAGNOSTIC SPECIES AND THEIR VEGETATION CLASSES IN NORTHERN ITALY

Abstract: Vegetation is often classified through phytosociology, which defines floristically and ecologically coherent units identified by diagnostic species. Since species- and community-environment relations are regulated by plant functional traits, it is likely that phytosociology has a strong functional underpinning, although the past and current phytosociology does not explicitly tackle this issue. Here we provide an analysis of functional traits of 221 woody species from Northern Italy, diagnostic of 21 European woody vegetation classes (including alien dominated ones). We assessed whether the functional space occupied by selected species corresponds to the physiognomy and ecology of the vegetation they represent, and whether this could help to evaluate major threats, such as invasion by alien species. For each species we collected from Authors’ datasets leaf trait data (leaf area, specific leaf area, leaf dry matter content, carbon to nitrogen ratio, leaf nitrogen content) and whole plant (plant height, seed mass) traits, and calculated Competitor, Stress-tolerant, Ruderal (CSR) scores. We identified the multidimensional functional trait space of diagnostic species and clustered classes according to their scores in the functional space, to check whether their physiognomy was coherently represented and mirrored in the CSR space. Lastly, we tested for differences between native and neophyte species and their overlap with classes. Diagnostic species mirrored the global spectrum of plant form and function, and classes showed a functional pattern coherent with their physiognomy and ecology. Evergreen dominated classes showed a similar convergence toward conservative characteristics and the stress-tolerant strategy, as opposed to deciduous forest classes that showed a tendency toward the competitive strategy. None of the classes showed a marked ruderal strategy, thus abiotic stress and biotic competition are the main ecological drivers affecting woody vegetation. Neophyte woody species exhibited relatively more competitive strategies compared to natives, and their invasion could be facilitated in resource-limited or mildly disturbed environments, should climate warming or increased nutrient availability occur. We demonstrated that plant traits and CSR strategies of woody diagnostic species reliably indicate the structure and functions of the phytosociological classes they represent, opening the way to the development of a “functional phytosociology”.

Keywords: CSR Adaptive Strategies, Forests, Shrublands, Global Spectrum, Neophytes, Plant Functional Traits, Structure and Functions, Typical Species

iForest 14 (6): 522-530 (2021) - doi: 10.3832/ifor3730-014
https://iforest.sisef.org/contents/?id=ifor3730-014

Short Communications: Estimation of canopy attributes of wild cacao trees using digital cover photography and machine learning algorithms

Duarte-Carvajalino JM, Paramo-Alvarez M, Ramos-Calderón PF, González-Orozco CE — 2021-11-17

Duarte-Carvajalino JM, Paramo-Alvarez M, Ramos-Calderón PF, González-Orozco CE

ESTIMATION OF CANOPY ATTRIBUTES OF WILD CACAO TREES USING DIGITAL COVER PHOTOGRAPHY AND MACHINE LEARNING ALGORITHMS

Abstract: Surveying canopy attributes while conducting fieldwork in the rain forest is time-consuming. Low-cost imagery such as digital cover photography is a potential source of information to speed up the process of vegetation assessments and reduce costs during expeditions. This study presents an image-based non-destructive method to estimate canopy attributes of wild cacao trees in two regions of the rain forest in Colombia, using digital cover photography and machine learning algorithms. Upward-looking photography at the base of each cacao tree and machine learning algorithms were used to estimate gap fraction (GF), foliage cover (FC), crown cover (CC), crown porosity (CP), clumping index (Ω), and leaf area index (LAI) of the canopy cover. Here we used the cacao wild trees found on forestry plots as a case study to test the application of low-cost imagery on the extraction and analysis of canopy attributes. Canopy attributes were successfully extracted from the canopy cover imagery and provided 92% of classification accuracy for the structural attributes of the canopy. Canopy cover attributes allowed us to differentiate between canopy structures of the Amazon and Pacific rainforests sites suggesting that wild cacao trees are associated with different vegetation types. We also compare classification results for the computer extraction of canopy attributes with a digital canopy cover benchmark. We conclude that our approach was effective to quickly survey canopy features of vegetation associated with and of crop wild relatives of cacao. This study allows highly reproducible estimates of canopy attributes using cover photography and state-of-the-art machine learning algorithms such as deep learning Convolutional Neural Networks.

Keywords: Canopy Attributes, Cover Photography, Colombia, Machine Learning, Deep Learning

iForest 14 (6): 517-521 (2021) - doi: 10.3832/ifor3936-014
https://iforest.sisef.org/contents/?id=ifor3936-014

Research Articles: Soil fauna communities and microbial activities response to litter and soil properties under degraded and restored forests of Hyrcania

Bazyari M, Etemad V, Kooch Y, Shirvany A — 2021-11-11

Bazyari M, Etemad V, Kooch Y, Shirvany A

SOIL FAUNA COMMUNITIES AND MICROBIAL ACTIVITIES RESPONSE TO LITTER AND SOIL PROPERTIES UNDER DEGRADED AND RESTORED FORESTS OF HYRCANIA

Abstract: Reforestation has long been the best practice to restore degraded forests due to human interventions. In this paper we investigated the effect of forest degradation (DNF) along with reforestation using 4 endemic species (Alnus subcordata, ASP; Acer velutinum, AVP; Cupressus sempervirens, CSP; Quercus castaneifolia Mey, QCP) on forest’s soil chemical and biological indicators compared to a close-to-virgin natural forest (VNF). For this study, a total of 24 physico-chemical and 25 biological and microbial indicators were measured in soils of all 6 forest stands along with the litter properties. Results showed that the lowest soil quality was observed under DNF, CSP, and QCP which was the result of forest cover degradation in DNF and low litter quality, especially low pH and high C:N, in CSP and QCP. Soil fauna communities were significantly affected by tree species. We found two times higher density of earthworms in VNF compared to ASP, but in DNF the density was 5 times lower than VNF. We found no epigeic earthworms in QCP, CSP and DNF and no endogeic earthworms in DNF. Acarina and Collembola density was high in VNF and ASP, but they showed significant differences (VNF>ASP), and their density sharply decreased in other stands, especially in CSP (3 times lower than VNF) and DNF (8 to 10 times lower than VNF). Nematode density was statistically equal in VNF, ASP, and AVP, but significantly lower in other stands. Protozoa, bacteria and fungi densities were significantly higher in VNF and ASP (VNF>ASP) compared to each other and other forest stands. Basal respiration, substrate induced respiration, microbial biomass N and P, and carbon availability index was also higher in VNF and ASP compared to other stands. Although VNF has the best condition because of old forest cover and high diversity, ASP soil showed significant improvements, demonstrating the importance of litter quality in soil restoration. Restoration effectiveness ranking of the four tested species on soil improvement are therefore ASP>AVP>QCP>CSP. The significant improvement of soil quality under ASP compared to other reforestated stands, only after 3 decades, emphasizes the importance of tree species selection and litter quality on soil chemical and biological restoration.

Keywords: Forest Restoration, Reforestation, Litter Quality, Soil Biological Activity, Soil Chemical Properties, Soil Fauna

iForest 14 (6): 490-498 (2021) - doi: 10.3832/ifor3583-014
https://iforest.sisef.org/contents/?id=ifor3583-014

Research Articles: Improving sustainability in wood coating: testing lignin and cellulose nanocrystals as additives to commercial acrylic wood coatings for bio-building

2021-11-11

Jusic J, Tamantini S, Romagnoli M, Vinciguerra V, Di Mattia E, Zikeli F, Cavalera M, Scarascia Mugnozza G

IMPROVING SUSTAINABILITY IN WOOD COATING: TESTING LIGNIN AND CELLULOSE NANOCRYSTALS AS ADDITIVES TO COMMERCIAL ACRYLIC WOOD COATINGS FOR BIO-BUILDING

Abstract: Wood use in bio-building should be considered as one of the main pillars of sustainability. According to international standards, beech wood (Fagus sylvatica L.) is a rather less durable species as it is subject to degradation due to weathering, though it is abundantly available to a more intense use. Service life of beech products and wood products in general can be enhanced by different methods, such as heat treatments, but new chances are offered by coating technologies. However, to ensure protection from wood-destroying organisms, most commercial coatings include components that could harm human health, other organisms and the environment. Therefore, coating industry has to develop more eco-friendly solutions in order to decrease its impact on human health and environment. The objective of this article was to modify commercial acrylic varnish by adding cellulose nanocrystals (CNC) and lignin (LN) extracted from beech wood and investigate their effect on water sorption, additive dispersion in the coating matrix and coating resistance to bacterial attack. Contact angle, weight gain and colour difference were analysed and FT-IR mapping was applied. The performance of CNC was promising, as it enhanced water sorption of the modified coating. However, protection against bacterial attack was not satisfying. On the other hand, chemically unmodified lignin did not show positive effects as component in the coating formulation. Nevertheless, the currently limited usage of these two renewable and abundant resources urgently calls for their more efficient utilization, in order to create additional value with industry side-streams producing novel bio-based materials. Further experiments are needed in order to obtain better dispersion of the particles and higher resistance to bacterial attacks.

Keywords: Acrylic Waterborne Coating, Beech Wood, Fagus sylvatica, Lignin, Cellulose Nanocrystal (CNC), FT-IR Mapping, Antibacterial Activity

iForest 14 (6): 499-507 (2021) - doi: 10.3832/ifor3782-014
https://iforest.sisef.org/contents/?id=ifor3782-014

Research Articles: Can species Cedrela fissilis Vell. be used in sites contaminated with toxic aluminum and cadmium metals?

2021-11-11

Castro Kuinchtner C, Silva Wertonge de Oliveira G, Miranda de Aguilar MV, Bernardy D, Berger M, Tabaldi LA

CAN SPECIES CEDRELA FISSILIS VELL. BE USED IN SITES CONTAMINATED WITH TOXIC ALUMINUM AND CADMIUM METALS?

Abstract: Toxic metals are among the main pollutants contributing to environmental degradation. Cadmium (Cd) and aluminum (Al) stand out among these metals as extremely toxic elements. The use of native species in reforestation programs can compensate for degradation and re-establish the ecological conditions of the affected environments. Cedrela fissilis Vell., popularly known as cedar, may be used as an alternative in phytoremediation, since it is a fast-growing native woody species widely distributed in tropical America. In this study we investigated the possibility of using C. fissilis in sites contaminated with Al and Cd by evaluating morphological, physiological, and biochemical variables of seedlings grown in hydroponic system. C. fissilis seedlings were subdivided into two experiments with a completely randomized design. The first experiment evaluated the effect of four Al concentrations, namely: 0 (complete nutrient solution without phosphorus), 25, 50 and 100 mg l-1. The second experiment evaluated four Cd concentrations, namely: 0 (complete nutrient solution), 25, 50 and 100 μM. Each sample unit consisted in a pot with four plants. Morphological, physiological and biochemical variables of seedlings were evaluated after 15-day exposure to different treatments in the hydroponic system. Aluminum concentration of 100 mg l-1 caused oxidative stress in C. fissilis seedlings, reduced shoot and root dry weight, and increased hydrogen peroxide contents, which led to lipid peroxidation. Cadmium concentration of 100 µM also damaged C. fissilis seedlings by significantly reducing root dry weight and involving the most severe effects on photosynthetic variables. Cadmium presence in the nutrient solution negatively affected morphophysiological and biochemical variables of Cedrela fissilis seedlings, and it was also harmful to their growth. Based on our results, the investigated species shows a sensitive behavior upon exposure to cadmium. On the other hand, C. fissilis tolerates high Al concentrations (up to 50 mg l-1), which suggests a moderate tolerance to this metal.

Keywords: Phytoremediation, Heavy Metals, Gas Exchange, Morphophysiological Variables

iForest 14 (6): 508-516 (2021) - doi: 10.3832/ifor3890-014
https://iforest.sisef.org/contents/?id=ifor3890-014

Research Articles: The willingness of inhabitants in medium-sized city and the city’s surroundings settlements to pay for recreation in urban forests in Poland

Mandziuk A, Fornal-Pieniak B, Ollik M — 2021-10-27

Mandziuk A, Fornal-Pieniak B, Ollik M

THE WILLINGNESS OF INHABITANTS IN MEDIUM-SIZED CITY AND THE CITY’S SURROUNDINGS SETTLEMENTS TO PAY FOR RECREATION IN URBAN FORESTS IN POLAND

Abstract: The aim of the study was to determine the willingness-to-pay (WTP) in exchange for recreation, to determine the dependency between the frequency of visits and willingness of forest users to make contributions for urban forests and the appearance of the forest, as well as the sociological characteristics of the respondents. The research was carried out on the example of the medium-sized city of Tarnów, southern Poland. To this aim, a survey was conducted on a group of 309 adult respondents inhabitants of Tarnów city and city’s surroundings settlements. For statistical analysis, the Classification And Regression Trees (CART) method was used to determine the dependency between the declared contributions and the characteristics of respondents, and the Principal Components Analysis for examining the dependency between WTP and the appearance (structure) of the forest. The dependency between the frequency of visits to urban forests and the demographics was analysed by chi-square test and one-way analysis of variance. The results showed that 97% of respondents are willing to make payments for urban forests, the amount of which differed depending on their place of residence, education, and age. Also, the vast majority of respondents make their WTP contributions dependent on the appearance of the forest. This applies in particular to a multi-stratum, multi-species forest with the undergrowth and recreational infrastructure. In addition, the frequency of visits to the area is affected by gender and place of residence. The obtained results are especially important for the recreation function of urban forests including willingness of inhabitants in Tarnów city and surroundings settlements.

Keywords: Recreation, Urban Forests, Willingness To Pay, Visual Aspect of Forest, Preferences of Tourist, Tarnów

iForest 14 (5): 483-489 (2021) - doi: 10.3832/ifor3758-014
https://iforest.sisef.org/contents/?id=ifor3758-014

Research Articles: Scots pine’s capacity to adapt to climate change in hemi-boreal forests in relation to dominating tree increment and site condition

2021-10-18

Mikalajunas M, Pretzsch H, Mozgeris G, Linkevičius E, Augustaitiene I, Augustaitis A

SCOTS PINE’S CAPACITY TO ADAPT TO CLIMATE CHANGE IN HEMI-BOREAL FORESTS IN RELATION TO DOMINATING TREE INCREMENT AND SITE CONDITION

Abstract: Forest site (FS) and meteorological conditions are recognized as the main factors affecting tree growth and whole-stand sustainability. This study aims to detect the combined effects of FS and meteorological conditions on tree ring formation of Scots pine (Pinus sylvestris L.), the most common tree species in Lithuania and hemi-boreal forests of northeastern Europe. We used data on stand structure and productivity from the Lithuanian National Forest Inventory (NFI) and stem radial increment series of dominating trees during the period 1993-2012 collected since 2013. Pine stem basal area increment (BAI) was chosen as the response variable, while temperature in March (°C) and precipitation in June (mm) were used as predictor variables, as they best express the effect of climate change on Lithuanian forests. We simulated the effects on dominating pine annual increment of deciduous tree species, mainly Betula sp. and the level of soil moisture and fertility, accounting in addition for the random effects of NFI network tract, plot direction, and tree number. A nonlinear mixed-effects model explained up to 68% of the variation in the BAI of pine trees. The annual pine trees BAI increased with the increase in the proportion of deciduous trees in pine stands. Increases in temperature and precipitation in considered months reinforced this positive effect on pine BAI, especially in mature pine stands in temporarily waterlogged meso-eutrophic FSs on mineral soils. A negative effect of deciduous trees on pine stem increment was observed only in nutrient-rich eutrophic and drained peatland FSs. Forestry treatments directed towards the increase in deciduous tree proportion in the most common normal or temporarily waterlogged meso-eutrophic and oligotrophic pine stands might increase the biodiversity and productivity of pine stands, and their sustainability in future climate change scenarios.

Keywords: Scots Pine, Basal Area Increment, Site Conditions, Meteorology, Mixed-effects, Hemi-Boreal Forests

iForest 14 (5): 473-482 (2021) - doi: 10.3832/ifor3703-014
https://iforest.sisef.org/contents/?id=ifor3703-014

Research Articles: Comparison of alternative harvesting systems for selective thinning in a Mediterranean pine afforestation (Pinus halepensis Mill.) for bioenergy use

Lerma-Arce V, Oliver-Villanueva JV, Segura-Orenga G, Urchueguia-Schölzel JF — 2021-10-16

Lerma-Arce V, Oliver-Villanueva JV, Segura-Orenga G, Urchueguia-Schölzel JF

COMPARISON OF ALTERNATIVE HARVESTING SYSTEMS FOR SELECTIVE THINNING IN A MEDITERRANEAN PINE AFFORESTATION (PINUS HALEPENSIS MILL.) FOR BIOENERGY USE

Abstract: Due to a continuous abandonment of marginal agricultural land, Mediterranean pine forests are growing both in biomass stock and area but remain mainly unmanaged. Pinus halepensis is one of the main pioneer species with strong expansion throughout the Mediterranean basin. In mature forests and pole stands, selective thinnings aimed to eliminate dominated and dead trees are necessary to improve the resilience and persistence of these forest ecosystems. Bioenergy market provides an opportunity to mobilise this woody material, helping to prevent and reduce wildfires in a context of climate change and energy transition. Despite the existing expertise on wood harvesting, there is a lack of practical knowledge about cost-effective methods for bioenergy use of selective thinnings in such forests. The objective of this study was to compare thinning harvesting methods in representative 63-year-old Pinus halepensis afforestation in pole stage for bioenergy uses, following the silvicultural treatments defined in the Spanish forest management plan. Time studies were performed over six representative plots in Navalón (Spain). Treatments included three plots with the traditional stem wood method combined with the logging of forest residues (integrated system), and three plots with the whole tree chipping (whole tree system). Time, productivity and fuel consumption were recorded for both systems. A woodchip quality assessment of each assortment was performed in the laboratory according to European standards. The results obtained demonstrated that time consumption and productivity were similar between the integrated harvesting system and the whole tree system. Regarding the total energy balance, it should be noted that both systems produce woodchips that contain over ten times more energy than that required to mobilise and process the obtained biomass. Fuel consumption, costs and degree of damage were slightly higher in the whole tree system due to the more intensive forwarding operation. The two assortments of woodchips in the integrated system had a higher (chipped log material) and lower quality (chipped crown material) than whole tree woodchips. In conclusion, integrated harvesting is a better option to diminish fuel consumption, cost and environmental impact, and also to obtain better quality woodchips for the production of added value biofuels (pellets).

Keywords: Pinus halepensis, Selective Thinnings, Bioenergy Harvesting, Logging Residues, Woodchips, Net Energy Efficiency, Whole-tree Biomass

iForest 14 (5): 465-472 (2021) - doi: 10.3832/ifor3636-014
https://iforest.sisef.org/contents/?id=ifor3636-014

Research Articles: Abundance and impact of egg parasitoids on the pine processionary moth (Thaumetopoea pityocampa) in Bulgaria

Mirchev P, Georgiev G, Georgieva M, Markoff I, Zaemdzhikova G, Matova M — 2021-10-02

Mirchev P, Georgiev G, Georgieva M, Markoff I, Zaemdzhikova G, Matova M

ABUNDANCE AND IMPACT OF EGG PARASITOIDS ON THE PINE PROCESSIONARY MOTH (THAUMETOPOEA PITYOCAMPA) IN BULGARIA

Abstract: We collected 2297 egg batches of the pine processionary moth (Thaumetopoea pityocampa) during the period 1991-2018 from 44 sites in Bulgaria. The sampling sites were classified into three groups according to T. pityocampa phenological form (early, late and both forms) as well as in two groups of its range (historical and newly colonized areas). Seven primary egg parasitoids were identified: Ooencyrtus pityocampae, Baryscapus servadeii, Pediobius bruchicida, Anastatus bifasciatus, Eupelmus (Macroneura) vesicularis, Eupelmus (Macroneura) vladimiri and Trichogramma sp., and one hyperparasitoid, Baryscapus transversalis. The average impact of egg parasitoids (the percentage of parasitized host eggs) on T. pityocampa in Bulgaria was 13.8%. The two main parasitoids, O. pityocampae and B. servadeii, parasitized about 90% of the host eggs. The remaining parasitoids were of insignificant consequence to the parasitism of the T. pityocampa eggs, but in areas recently colonized by the pest, A. bifasciatus and Trichogramma sp. had a noticeable share (up to 33% of the impact). In old habitats of the host (areas colonized more than 10 years), the impact was almost two times higher than in new ones (15.3% vs. 8.6%). This could be attributed to B. servadeii, which was rare in newly colonized areas of T. pityocampa (impact 0.5%), but strongly dominant in old habitats (impact 7.2%). In contrast, O. pityocampae had a significant impact in new habitats (4.9%), which increased only slightly over time, reaching 6.0% in old habitats. There was no significant difference between the percentage of parasitism of the early and late form of the pine processionary moth (14.8% vs. 15.9%). However, there was a significant difference in the share of separate species in the parasitoid complex: in the early form, B. servadeii definitely dominated (63% of the infested eggs), while in the late form O. pityocampae dominated, although not so strongly (52% of the infested eggs). This difference is most likely due to the phenological characteristics of the parasitoids and the two forms of T. pityocampa. B. transversalis secondarily infested about 5% of the eggs of O. pityocampae and B. servadeii. This percentage was slightly lower for new habitats and habitats of the early form of pine processionary moth (3% and 4%, respectively). The impacts of the main parasitoids O. pityocampae and B. servadeii as well as the total impact of the parasitoid complex as a whole decreased with altitude. Conversely, the impacts of A. bifasciatus and Trichogramma sp. slightly increased with altitude probably due to the reduced competition of the main parasitoids.

Keywords: Thaumetopoea pityocampa, Distribution, Habitats, Expansion, Phenological Forms, Egg Parasitism, Bulgaria

iForest 14 (5): 456-464 (2021) - doi: 10.3832/ifor3538-014
https://iforest.sisef.org/contents/?id=ifor3538-014

Research Articles: Daily prediction modeling of forest fire ignition using meteorological drought indices in the Mexican highlands

2021-09-28

Vilchis-Francés AY, Díaz-Delgado C, Becerril Piña R, Mastachi Loza CA, Gómez-Albores M&, Bâ KM

DAILY PREDICTION MODELING OF FOREST FIRE IGNITION USING METEOROLOGICAL DROUGHT INDICES IN THE MEXICAN HIGHLANDS

Abstract: We analyzed the behavior of forest fires for daily prediction purposes in one of the regions with the highest fire incidence in Mexico. The main objective was to build logistic regression models (LRMs) for daily prediction of forest fire ignition based on meteorological drought indices. We built 252 LRMs for seven types of vegetation cover of greater representativeness and interest for the study area. Three dynamic variables were considered to estimate daily dryness in combustible fuels based on the effective drought index and the standardized precipitation-evapotranspiration index. Additionally, two weather data sources were included in drought indices: conventional weather stations (CWS) and automatic weather stations (AWS). Prediction efficiency assessment for LRMs was done through the relative operating characteristic (ROC) and model precision efficiency (MPE). The results show that LRMs using data from CWS performed relatively better than those based on data from AWS, as the former data sources have higher spatial density and thus generate predictions with higher accuracy (ROC ≥ 0.700, MPE ≥ 0.934). For both data sources, the use of standardized precipitation-evapotranspiration index as a fuel dryness estimator is recommended, as it reflects an atmospheric moisture balance between precipitation and reference evapotranspiration (ROC ≥ 0.734, MPE = 1). Such predictive models can be used as inputs in early warning systems for forest fire prevention or mitigation.

Keywords: Logistic Regression, Effective Drought Index, Standardized Precipitation-Evapotranspiration Index, Conventional Weather Stations, Automatic Weather Stations

iForest 14 (5): 437-446 (2021) - doi: 10.3832/ifor3623-014
https://iforest.sisef.org/contents/?id=ifor3623-014

Research Articles: Using nano-scale Fe0 particles and organic waste to improve the nutritional status of tree seedlings growing in heavy metal-contaminated soil

Tafazoli M, Hojjati SM, Biparva P, Kooch Y, Lamersdorf N — 2021-09-28

Tafazoli M, Hojjati SM, Biparva P, Kooch Y, Lamersdorf N

USING NANO-SCALE FE0 PARTICLES AND ORGANIC WASTE TO IMPROVE THE NUTRITIONAL STATUS OF TREE SEEDLINGS GROWING IN HEAVY METAL-CONTAMINATED SOIL

Abstract: The rehabilitation of heavy metal-contaminated lands is a challenging issue worldwide. The application of effective eco-friendly techniques and materials is necessary for amending the contaminated soils, and the in-situ results should be examined. The present study investigated the effect of zero-valent iron-nanoparticles (Fe0-NPs) and cellulosic wastes (CW) on the lead (Pb) and cadmium (Cd) uptake and nutrients’ (N, P, K) concentration of maple seedlings in contaminated soil. First, one-year-old seedlings were planted in pots containing unpolluted soil (volume = 3 Kg), and then the soil was contaminated by adding Pb (0, Pb100, Pb200, and Pb300 mg kg-1) and Cd (0, Cd10, Cd20, and Cd30 mg kg-1) solutions. The CW (0, 10, 20, 30 g/100g soil) and Fe0-NPs (0, 1, 2, 3 mg kg-1) treatments were applied to the soil before and after Pb and Cd addition, respectively. The biomass of seedlings and the concentration of nitrogen, potassium, and phosphorus in leaves were measured. Leaves, stems, and roots were digested to measure the Pb and Cd concentrations. Results showed that CW and Fe0-NPs improved N, P, and K concentrations in leaves at all levels of contamination. The lowest concentration of Pb and Cd in all organs and treatments was observed in the highest level of Fe0-NPs. The cellulosic waste and Fe0-NPs (the highest level only) significantly increased the soil pH at all levels of contamination. Our findings suggested that the use of Fe0-NPs (3 mg kg-1) and CW (30g/100g soil) could be appropriate for reducing the bioavailability of Pb and Cd in contaminated soil and improving the growth of maple seedlings.

Keywords: Soil Amendments, Zero-valent Iron, Heavy Metal Immobilization, Forest Rehabilitation

iForest 14 (5): 447-455 (2021) - doi: 10.3832/ifor3821-014
https://iforest.sisef.org/contents/?id=ifor3821-014

Research Articles: A multisource approach helps to detect a forest as a reference site in an intensively used rural landscape (Uckermark, NE Germany)

2021-09-21

Wulf M, Kaiser K, Mrotzek A, Geiges-Erzgräber L, Schulz L, Stockmann I, Schneider T, Kappler C, Bens O

A MULTISOURCE APPROACH HELPS TO DETECT A FOREST AS A REFERENCE SITE IN AN INTENSIVELY USED RURAL LANDSCAPE (UCKERMARK, NE GERMANY)

Abstract: The sharp decline in seminatural areas worldwide is undisputed, but the consequences of this decline, apart from the loss of biodiversity, cannot be fully assessed. To restore ecosystems or landscapes, it is essential to have so-called reference sites. We want to show how reliable reference sites can be found in heavily used landscapes with the help of independent sources, and we present an approach that can be used in other regions, because it is very well suited for developing essential databases in the context of theses at different levels. A forest of seminatural stocking was selected in northeast Germany as a case study. The mapping of archival sources and the analyses of historical maps as well as field investigations were combined to reconstruct the dynamics of vegetation and soil for the last several centuries to thousands of years. Palynological data from nearby sites show that the study area has been forested for several millennia and has been less influenced by humans in the last 450 years. Together with historical maps of tree species composition, it allows to infer that the specific forest has been preserved in good ecological conditions for at least 250 years. Soil inventory and field studies on two catenas and corings support this conclusion, as they rarely show signs of anthropogenic erosion and related colluviation. Using a multisource approach, it is possible to identify potential reference sites that provide a reliable basis for ecosystem or landscape restoration.

Keywords: Ancient Forest, Geo-bio-archives, Historic Maps, Land Use Legacy, Pollen Analysis, Reference Site

iForest 14 (5): 426-436 (2021) - doi: 10.3832/ifor3774-014
https://iforest.sisef.org/contents/?id=ifor3774-014

Research Articles: Forest management with carbon scenarios in the central region of Mexico

2021-09-15

Ramírez-Martínez A, González-Guillén MDJ, De Los Santos-Posadas HM, Ángeles-Pérez G, Santiago-García W

FOREST MANAGEMENT WITH CARBON SCENARIOS IN THE CENTRAL REGION OF MEXICO

Abstract: The search for mechanisms to mitigate global warming has generated a series of proposals to reduce deforestation and promote conservation of forests as carbon stocks through financial or in-kind support. However, the economic implications of including carbon sequestration in forest for timber production have not been dealt with in depth, and the conditions in which combined production might be a profitable option to forest owners, particularly in Mexico, are unknown. The aim of this study was to quantify carbon sequestration in a central region of Mexico and evaluate the profitability of selling carbon credits as well as timber products. Data and information used comes from three inventories (2013, 2014 and 2016) taken in 160 permanent sampling plots of 400 m2 each; forest management costs per hectare were obtained through interviews to the landowners, and the profitability was assessed using the economic indicators Net Present Value (NPV), Internal Return Rate (IRR), Benefit-Cost Ratio (BCR), and Land Expected Value (LEV). The results indicate that, in areas of low productivity, carbon sequestration is profitable only at a low discount rate (3.5%) and a high price of the ton CO2e (USD 100 ha-1 year-1). However, under combined production, the optimal rotation periods are longer, depending on the discount rate and price of sequestered carbon. Therefore, timber production will continue to be the main economic activity, until the rules of operation of the different mechanisms created for carbon sequestration become more flexible and the carbon markets offer more attractive incentives.

Keywords: Climate Change, Carbon Sequestration, Productivity, Financial Profitability, Optimal Rotation

iForest 14 (5): 413-420 (2021) - doi: 10.3832/ifor3630-014
https://iforest.sisef.org/contents/?id=ifor3630-014

Short Communications: Competition effects and economic scenarios in an agroforestry system with cereal crops and wood plantations: a case study in the Po Valley (Italy)

Rosso L, Cantamessa S, Chiarabaglio PM, Coaloa D — 2021-09-15

Rosso L, Cantamessa S, Chiarabaglio PM, Coaloa D

COMPETITION EFFECTS AND ECONOMIC SCENARIOS IN AN AGROFORESTRY SYSTEM WITH CEREAL CROPS AND WOOD PLANTATIONS: A CASE STUDY IN THE PO VALLEY (ITALY)

Abstract: This study aims to evaluate the economic feasibility of agroforestry management in temperate latitudes. The surveys carried out in 1971 by Prevosto on the yields of wheat and rice combined with poplars was revised with updated prices to assess whether an agroforestry system can positively influence farm incomes. Based on Prevosto’s dataset, four scenarios were simulated with poplar clone I-214, assuming four different positions of the poplar row (along the field borders, towards the cardinal points) and the relative shadows. The results show that the agroforestry system is economically advantageous, especially for wheat, and is directly related to wood price. The achievable benefits could be more significant with political and financial support that promotes these practices, taking into account the fundamental ecosystem services they provide.

Keywords: Agroforestry, Poplar, Cereal Crop, Shading Effect, Tree Row Orientation, Economic Evaluation, Threshold Area Convenience

iForest 14 (5): 421-425 (2021) - doi: 10.3832/ifor3842-014
https://iforest.sisef.org/contents/?id=ifor3842-014

Short Communications: Is microbial biomass measurement by the chloroform fumigation extraction method biased by experimental addition of N and P?

Mori T, Wang S, Wang C, Mo J, Zhang W — 2021-09-04

Mori T, Wang S, Wang C, Mo J, Zhang W

IS MICROBIAL BIOMASS MEASUREMENT BY THE CHLOROFORM FUMIGATION EXTRACTION METHOD BIASED BY EXPERIMENTAL ADDITION OF N AND P?

Abstract: The chloroform fumigation extraction (CFE) method determines microbial biomass carbon (MBC) or nitrogen (MBN) by calculating the increase in extractable carbon (C) or nitrogen (N) due to microbial lysis during chloroform fumigation. In China, many studies have focused on the impacts of N and phosphorus (P) addition on soil MBC and MBN in forest ecosystems, where substantial atmospheric N deposition has strongly acidified soils. The addition of nutrients may alter the extraction process applied in the CFE method, potentially influencing the MBC and MBN determined by the CFE method independently of the actual microbial biomass. In this study, we tested whether the MBC and MBN determined by the CFE method were biased by the experimental addition of N and P in strongly acidified Chinese forest soils by adding N and P to the soils immediately before chloroform fumigation, which should not affect the actual microbial biomass. P addition significantly elevated the dissolved organic carbon (DOC) content, especially after fumigation, while N addition significantly reduced the dissolved nitrogen (DN) content. The added N was subtracted using blank samples without soil. However, the altered DOC and DN contents did not affect the MBC and MBN contents determined by the CFE method. In conclusion, our study suggests that the CFE is a relatively robust method to test the impacts of nutrient addition on microbial biomass in the strongly acidified soils of Chinese forests. We also suggested that: (i) even if a fertilization experiment results in an elevated DOC content following P addition, it does not necessarily indicate a stimulation of DOC production by microbes; and (ii) the soil adsorption capacity or the strength of microbial N uptake during the extraction procedure applied in the CFE method may affect the determination of MBN by influencing the DN extraction efficiency.

Keywords: Chloroform Fumigation Extraction, Microbial Biomass, Nitrogen, Phosphorus, Soil, Tropical Forest

iForest 14 (5): 408-412 (2021) - doi: 10.3832/ifor3374-014
https://iforest.sisef.org/contents/?id=ifor3374-014

Research Articles: Cryptogamic epiphytes and microhabitat diversity on non-native green ash (Fraxinus pennsylvanica Marsh., Oleaceae) in urban habitats

Dittrich S, Thiem E, Albrecht BM, von Oheimb G — 2021-09-01

Dittrich S, Thiem E, Albrecht BM, von Oheimb G

CRYPTOGAMIC EPIPHYTES AND MICROHABITAT DIVERSITY ON NON-NATIVE GREEN ASH (FRAXINUS PENNSYLVANICA MARSH., OLEACEAE) IN URBAN HABITATS

Abstract: With the increased planting of non-native trees within urban environments there is a need for investigating the impacts they may have on the indigenous biodiversity. In this study, we explored the diversity of epiphytic lichens and bryophytes as well as the tree-related microhabitats on planted, non-native green ash Fraxinus pennsylvanica and compared it to that of indigenous Fraxinus excelsior and Quercus robur. We conducted sampling on trees of similar growing conditions and size within two cities of eastern Germany (Dresden and Dessau-Roßlau). In our analysis we did not find any significant differences in epiphyte diversity and abundance. By contrast, microhabitat diversity was significantly higher on F. pennsylvanica than on the indigenous tree species, which we attribute to the pioneer character of F. pennsylvanica with faster ageing. Our results underline a low impact of F. pennsylvanica on epiphytic lichen and bryophyte diversity, while indigenous animals might even benefit from the higher diversity and frequency of microhabitats on trees of this species. Therefore, its use as an ornamental tree should not be generally rejected in urban environments.

Keywords: Alien Trees, Bryophytes, Invasiveness, Lichens

iForest 14 (5): 393-399 (2021) - doi: 10.3832/ifor3739-014
https://iforest.sisef.org/contents/?id=ifor3739-014

Research Articles: Characterization of technological properties of matá-matá wood (Eschweilera coriacea [DC.] S.A. Mori, E. odora Poepp. [Miers] and E. truncata A.C. Sm.) by Near Infrared Spectroscopy

Nascimento CSD, Nascimento CCD, Araújo RDD, Soares JCR, Higuchi N — 2021-09-01

Nascimento CSD, Nascimento CCD, Araújo RDD, Soares JCR, Higuchi N

CHARACTERIZATION OF TECHNOLOGICAL PROPERTIES OF MATá-MATá WOOD (ESCHWEILERA CORIACEA [DC.] S.A. MORI, E. ODORA POEPP. [MIERS] AND E. TRUNCATA A.C. SM.) BY NEAR INFRARED SPECTROSCOPY

Abstract: The aim of this study was to determine the technological properties (chemical, mechanical and physical) of Eschweilera sp. woods using near infrared spectroscopy (NIRS). NIR spectroscopy proved to be efficient for chemical analysis (extractives, lignin and carbohydrates) and physical-mechanical testing (moisture content, basic density - BD, modulus of elasticity - MOE and modulus of rupture - MOR) of wood, providing a powerful tool for use in sustainable forest management activities in the Amazon. Wood samples from three trees of each Eschweilera species were collected from the Experimental Station of Tropical Forestry/INPA/Brazil. Specimens were extracted from the cross-sectional area (20 × 20 × 30 mm) in the direction sapwood-heartwood. NIR spectra (4.000-10.000 cm-1) were then obtained from the samples (moisture 12%) using Fourier-transform spectrometry. The Partial Least Squares (PLS) regression prediction models for the chemical, mechanical and physical properties of Amazonian woods were used for quantification. The results for total extractives (both in toluene and ethanol) and hot water solubility showed a maximum extractive concentration of 7.66% and 3.13% for E. odora (yellow matá-matá), including several compounds with low molecular weight, such as resins, gums, terpenes, alkaloids, flavonoids, and tannins. The highest concentration of phenolic substances (tannins) was found in E. Truncata (black matá-matá, 10.00%). The macrocomponents (primary metabolism) of Eschweilera species were in the range of 44.20-46.33% for cellulose and 28.89-31.21% for lignin. Mineral compounds (ash) were quantified in concentrations < 0.70%. The predictive results for the physical and mechanical properties of matá-matá wood are in the standard range for tropical woods. The higher calorific value (HCV) varied from 4.993-5.033 cal g-1 and the BD from 0.78-0.88 g m-3. Regarding moisture, the highest content was observed in E. truncata (13.46%). Values for mechanical resistance were in the range of 14,253-17,447 MPa for MOE and 146.04-175.73 MPa for MOR, with the greatest strength attributed to E. truncata wood. The values obtained for the wood technological properties of E. coriacea (white matá-matá), E. odora (yellow matá-matá) and E. truncata (black matá-matá) were compatible with those obtained by destructive determination of tropical species and also for other species of the genus Eschweilera.

Keywords: Eschweilera, Amazonian Woods, Wood Chemistry, Physico-mechanical Properties, NIR Spectroscopy, Forest Management

iForest 14 (5): 400-407 (2021) - doi: 10.3832/ifor3748-014
https://iforest.sisef.org/contents/?id=ifor3748-014

Research Articles: Long-term dynamics of stand structure and regeneration in high-stocked selection fir-beech forest stand: Croatian Dinarides case study

Cavlović J, Teslak K, Beljan K, Vedriš M, Andabaka M — 2021-08-24

Cavlović J, Teslak K, Beljan K, Vedriš M, Andabaka M

LONG-TERM DYNAMICS OF STAND STRUCTURE AND REGENERATION IN HIGH-STOCKED SELECTION FIR-BEECH FOREST STAND: CROATIAN DINARIDES CASE STUDY

Abstract: In recent decades, changes in stand structure in Central European fir-beech forests, such as accumulation of large-diameter firs, fir dieback, and poor regeneration, have been well documented. Besides environmental factors, light harvesting was suggested as one of the main drivers of the negative structural dynamics of these forests in Croatia. This study applied the MOSES 3.0 stand simulator on permanent sample plot data to reconstruct stand development over the past 20 years and simulate long-term projections of selection stand structure and regeneration with respect to theoretical values, using three management regimes differing by the applied harvesting intensity (traditionally applied, theoretical intensity, and no management). Sample plot data from three sets of detailed measurements (1992, 2002, and 2012) were used for validation of the simulator, and eleven 10-year cycles of management were then simulated under the above management scenarios. Results showed a positive influence of harvest intensity on stand regeneration and the achievement of a targeted selection structure in the long term. Two management scenarios predicted a decrease in stand volume (34% and 40%, respectively), an increase in the initial percentage (28%) of beech and maple (58% and 75%, respectively), and the achievement of optimal stand regeneration of 11-13 recruited trees per hectare annually (60% firs). No management scenario could achieve old-growth structure (accumulation of standing stock, large trees, and deadwood). The theoretical intensity scenario was evaluated as the better approach to be applied in this type of forest stands in Croatia.

Keywords: Selection Harvest, Stand Growth Simulator, Development of DBH Distribution, Tree Species Composition, Natural Regeneration, Old-growth Structure

iForest 14 (4): 383-392 (2021) - doi: 10.3832/ifor3638-014
https://iforest.sisef.org/contents/?id=ifor3638-014

Short Communications: Evidence of Alectoris chukar (Aves, Galliformes) as seed dispersal and germinating agent for Pistacia khinjuk in Balochistan, Pakistan

Essa M, Ziauddin Z, Khan MA, Imran M, Saeed AE — 2021-08-22

Essa M, Ziauddin Z, Khan MA, Imran M, Saeed AE

EVIDENCE OF ALECTORIS CHUKAR (AVES, GALLIFORMES) AS SEED DISPERSAL AND GERMINATING AGENT FOR PISTACIA KHINJUK IN BALOCHISTAN, PAKISTAN

Abstract: Seed dispersal is a key process for the distribution of wild fruit plants in forests and/or rangeland. The ecological role of Alectoris chukar as a seed dispersal agent was hardly known to date, though its diet consists of herbs, shrubs, and fleshy fruits of wild plants. Here we report the first evidence of seed dispersal and germination of wild pistachio plant (Pistacia khinjuk Stocks) favored by Alectoris chukar from the district Killa Saifullah and Pishin in Balochistan, Pakistan. Fecal droppings of Alectoris chukar were collected by a suitable sampling method from August to September 2020. Fecal droppings were kept in plastic bags, and later washed thoroughly, identified, and counted for Pistacia khinjuk seeds, which have a characteristic rounded and tough seed coat easily distinguishable from other seeds. Out of a total of 840 fecal samples collected, 557 were identified as Pistacia khinjuk seeds. A comparative germination trial was carried out for pistachio seeds both from Alectoris chukar fecal droppings and manually collected from mother trees in the forest. After passing through the chukar gut, the seeds were still viable and showed a faster germination rate as compared with seeds collected from mother trees and directly sown in the soil. The results revealed that Alectoris chukar is an important spreading and germinating agent for seeds of pistachio plants in suitable habitats and could contribute in the long term to modify the ground vegetation of (sub)arid regions depending on its dietary preferences.

Keywords: Alectoris chukar, Balochistan, Fecal Dropping, Pistacia khinjuk, Seed Dispersal, Seed Germination

iForest 14 (4): 378-382 (2021) - doi: 10.3832/ifor3691-014
https://iforest.sisef.org/contents/?id=ifor3691-014

Research Articles: Temporal patterns control carbon balance in forest and agricultural tropical peatlands in North Selangor, Malaysia

2021-08-10

Vijayanathan J, Ishak MF, Parlan I, Omar H, Osumanu Haruna A, Lion M, Hassan MG, Jong RM, Samah AKA

TEMPORAL PATTERNS CONTROL CARBON BALANCE IN FOREST AND AGRICULTURAL TROPICAL PEATLANDS IN NORTH SELANGOR, MALAYSIA

Abstract: Tropical peat swamp forests can sequester significant amount of carbon (C). However, there is dearth of understanding on the tropical soils’ C stocks and emissions because of the changes in peatland use, land use policies, and micro-climate. The objective of this study was to determine the C stocks and fluxes of two peat swamp forests and a peatland under mixed cropping in Selangor, Malaysia. Standard procedures were used to determine aboveground biomass, belowground biomass, selected peat soil physical, chemical, and biological properties, and environmental variables that are related to peat soil respirations. The mean C stocks for the peat swamp forest and mixed cropping sites were 1788.79 Mg C ha-1 and 1023.57 Mg C ha-1, respectively. The carbon dioxide emission rates of peat swamp forest and mixed cropping sites ranged from 7.20 to 73.13 tCO2 ha-1 year-1 and 26.50 to 43.43 tCO2 ha-1 year-1, respectively. These emissions are related to seasonal changes because the relative humidity, soil temperature, and ground water of the experimental sites had significant effects on soil respiration. Unlike the mixed cropping sites, the fluxes of the peat swamp forest were significantly higher in the dry season compared with the wet season. These findings suggest that peat soil respiration is controlled by relative humidity, temperature, and the changes in ground water table. Continued monitoring and conservation efforts to preserve stored C in peatlands are essential.

Keywords: Peat Characteristics, Carbon Storage, Carbon Dioxide Fluxes, Cash Crop Cultivation, Seasonal Variations

iForest 14 (4): 362-369 (2021) - doi: 10.3832/ifor3700-014
https://iforest.sisef.org/contents/?id=ifor3700-014

Research Articles: Short-term effects in canopy gap area on the recovery of compacted soil caused by forest harvesting in old-growth Oriental beech (Fagus orientalis Lipsky) stands

Jourgholami M, Feghhi J, Tavankar F, Latterini F, Venanzi R, Picchio R — 2021-08-10

Jourgholami M, Feghhi J, Tavankar F, Latterini F, Venanzi R, Picchio R

SHORT-TERM EFFECTS IN CANOPY GAP AREA ON THE RECOVERY OF COMPACTED SOIL CAUSED BY FOREST HARVESTING IN OLD-GROWTH ORIENTAL BEECH (FAGUS ORIENTALIS LIPSKY) STANDS

Abstract: Natural treefall gaps have a substantial role in maintaining soil and plant diversity in old-growth forests. However, the amount of information on the effects of gaps on the recovery of physical and chemical properties of compacted soils is scarce. We tested the hypothesis that natural treefall gaps accelerate the restoration of compacted soil by enhancing biological and microbial activity in the topsoil after a period of five years. Five years after a ground-based skidding operation in the Hyrcanian forest, the recovery levels of soil properties were compared among different treatments including natural canopy gaps with an area of 200 m2 (NCG), clear-cuts with an area of 1600 m2 (CC), disturbed trails under a dense canopy (DDC), and an undisturbed area (UND) as control. The lowest soil bulk density (1.07 g cm-3), penetration resistance (1.11 MPa), and the highest macroporosity (36.3%), and sand content (14.4%) among treatments were recorded for the NCG followed by DDC and CC treatments. Significantly lower values of soil pH, and electric conductivity and the highest values of soil organic C, total N, available P, K, Ca, and Mg were detected under the NCG followed by the DDC and CC treatments, as compared to the UND area. The highest values of earthworm density and dry mass, and soil microbial respiration were found in the NCG followed by the DDC and CC treatments. Fine root biomass was significantly higher in the UND area (92.27 g m-2) followed by the DDC, NCG and CC treatments. We can conclude that the effects of gap size on the recovery values of compacted soil were significant in terms of greater nutrient availability and higher earthworm density and dry mass, suggesting that mimicking natural canopy gap was more effective than the clear-cut gap (CC) for the resilience of the forest stand in the restoration of soil quality.

Keywords: Canopy Gap Area, Timber Extraction, Skid Trails, Soil Compaction, Forest Soil Recovery, Earthworm, Hyrcanian Forest

iForest 14 (4): 370-377 (2021) - doi: 10.3832/ifor3432-014
https://iforest.sisef.org/contents/?id=ifor3432-014

Research Articles: A geographically weighted deep neural network model for research on the spatial distribution of the down dead wood volume in Liangshui National Nature Reserve (China)

Sun Y, Ao Z, Jia W, Chen Y, Xu K — 2021-07-27

Sun Y, Ao Z, Jia W, Chen Y, Xu K

A GEOGRAPHICALLY WEIGHTED DEEP NEURAL NETWORK MODEL FOR RESEARCH ON THE SPATIAL DISTRIBUTION OF THE DOWN DEAD WOOD VOLUME IN LIANGSHUI NATIONAL NATURE RESERVE (CHINA)

Abstract: In natural forest ecosystems, there is often abundant down dead wood (DDW) due to wind disasters, which greatly changes the size and structure of forests. Accurately determining the DDW volume (DDWV) is crucial for sustaining forest management, predicting the dynamic changes in forest resources and assessing the risks of natural disasters or disturbances. However, existing models cannot accurately express the significant spatial nonstationarity or complexity in their spatial relationships. To this end, we established a geographically weighted deep neural network (GWDNN) model that constructs a spatially weighted neural network (SWNN) through geographic location data and builds a neural network through stand factors and remote sensing factors to improve the interpretability of the spatial model of DDWV. To verify the effectiveness of this method, using 2019 data from Liangshui National Nature Reserve, we compared model fit, predictive ability and residual spatial autocorrelation among the GWDNN model and four other spatial models: an ordinary least squares (OLS) model, a linear mixed model (LMM), a geographically weighted regression (GWR) model and a deep neural network (DNN) model. The experimental results show that the GWDNN model is far superior to the other four models according to various indicators; the coefficient of determination R2, root mean square error (RMSE), mean absolute error (MAE), Moran’s I and Z-statistic values of the GWDNN model were 0.95, 1.05, 0.77, -0.01 and -0.06, respectively. In addition, compared with the other models, the GWDNN model can more accurately depict local spatial variations and details of the DDWV in Liangshui National Nature Reserve.

Keywords: Down Dead Wood Volume (DDWV), Ordinary Least Squares (OLS) Model, Linear Mixed Model (LMM), Geographically Weighted Regression (GWR) Model, Deep Neural Network (DNN) Model, Geographically Weighted Deep Neural Network (GWDNN) Model

iForest 14 (4): 353-361 (2021) - doi: 10.3832/ifor3705-014
https://iforest.sisef.org/contents/?id=ifor3705-014

Research Articles: Method for the analysis of the relationship between forest cover and streamflow in watersheds

Ferraz FT, Zanetti SS, Cecílio RA, De Carvalho D, De Oliveira FR — 2021-07-21

Ferraz FT, Zanetti SS, Cecílio RA, De Carvalho D, De Oliveira FR

METHOD FOR THE ANALYSIS OF THE RELATIONSHIP BETWEEN FOREST COVER AND STREAMFLOW IN WATERSHEDS

Abstract: The relationship between forest cover and streamflow of watersheds is complex and still controversial in the scientific literature. To investigate suchrelationship we propose an alternative method which requires the following information for each watershed: percentage of forest cover, annual rainfall, average specific streamflow (qave), and minimum mean specific streamflow in seven consecutive days (q7). As a case study, we analyzed a dataset composed by 25 watersheds located in the Espírito Santo State (ESS), Brazil. We conducted simple and multiple linear regression analyses as well as partial correlation analysis between the above parameters. To reduce the effect of heterogeneity of environmental factors, watersheds with similar characteristics in term of rainfall, drainage area, and both rainfall and drainage area were grouped by cluster analysis, and the above regression and correlation analysis was repeated on each group. Our results using the whole dataset showed that forest cover has a negative relationship with watershed streamflow. The analysis of homogeneous groups of watersheds showed that the average minimum streamflow during seven days (q7) was more sensitive to the presence of forest cover, showing a negative relationship, especially in watersheds with low annual rainfall, while in areas with high precipitation, the annual rainfall showed a strong influence on the hydrological responses of watersheds, masking the effect of forest cover. The proposed method may be easily extended to other areas, and allowsthe inclusion of other relevant environmental variables according to specific cases.

Keywords: Forests, Cluster Analysis, Water Regime, Land Use, Watershed Management

iForest 14 (4): 344-352 (2021) - doi: 10.3832/ifor3536-014
https://iforest.sisef.org/contents/?id=ifor3536-014

Research Articles: Response of Chinese sea buckthorn clonal growth and photosynthetic physiological mechanisms toward a soil moisture gradient

Bai S, Nie K, Ji S, Chen S, Yao Z, Li G, Tang C, Guo F — 2021-07-15

Bai S, Nie K, Ji S, Chen S, Yao Z, Li G, Tang C, Guo F

RESPONSE OF CHINESE SEA BUCKTHORN CLONAL GROWTH AND PHOTOSYNTHETIC PHYSIOLOGICAL MECHANISMS TOWARD A SOIL MOISTURE GRADIENT

Abstract: Studies have reported on the regulation of clonal growth in Chinese sea buckthorn in response to environmental resource availability, but these studies have been limited to external mechanisms. In this report, we controlled irrigation to generate a soil moisture gradient in order to examine the photosynthetic physiological mechanisms regulating clonal growth in this species. The results indicated that as irrigation intensity increased, the soil water content increased vertically and tissue water content first increased and then decreased. Furthermore, Rubisco activase (RCA) and Mg-chelatase H subunit (CHLH) gene expression levels, photosynthetic capacity (net photosynthetic rate, transpiration rate, chlorophyll content, and stomatal conductance), and clonal growth (ramet growth, clonal proliferation, clonal propagation) all showed a quadratic parabolic change (i.e., first increasing and then decreasing). In addition, gene expression levels and tissue water content, photosynthetic capacity and gene expression levels, and clonal growth and photosynthetic capacity were all significantly positively correlated. When irrigation intensity (soil water content) is exceedingly low or high, the tissue water content is also low, RCA and CHLH gene expression levels are low, photosynthetic capacity is weak, clonal growth ability is inhibited, and clonal growth layout tends toward the “guerrilla type.” This type manifests as fewer and smaller clonal daughter ramets that are sparsely distributed with reduced clonal organ extension ability and branching intensity. When irrigation intensity (soil water content) is moderate, the tissue water content, gene expression levels, and photosynthetic capacity is high, clonal growth ability is completely uninhibited, and the clonal growth layout tends toward the “aggregated type.” This type is associated with numerous large clonal daughter ramets that are densely distributed with high clonal organ extension ability and branching intensity. Therefore, as irrigation intensity continuously changes from inordinately low to moderate to exceedingly high, Chinese sea buckthorn regulates clonal growth by photosynthetic capacity through photosynthetic gene expression. This results in a clonal growth layout continuum of “guerrilla-aggregated-guerrilla” that depends on irrigation intensity.

Keywords: Clonal Growth, Irrigation Intensity, Tissue Water Content, Photosynthetic Genes, RCA and CHLH Gene Expression, Hippophae rhamnoides ssp. sinensis, Mu Us Sandy Land

iForest 14 (4): 337-343 (2021) - doi: 10.3832/ifor3564-014
https://iforest.sisef.org/contents/?id=ifor3564-014

Research Articles: Potential relationships of selected abiotic variables, chemical elements and stand characteristics with soil organic carbon in spruce and beech stands

Horváth M, Bečvárová PH, Šarapatka B, Vencálek O, Zouhar V — 2021-07-09

Horváth M, Bečvárová PH, Šarapatka B, Vencálek O, Zouhar V

POTENTIAL RELATIONSHIPS OF SELECTED ABIOTIC VARIABLES, CHEMICAL ELEMENTS AND STAND CHARACTERISTICS WITH SOIL ORGANIC CARBON IN SPRUCE AND BEECH STANDS

Abstract: Increasing attention is given to carbon sequestration in forest soil with regard to climate change and the mitigation of its impacts; therefore, it is very important to know which parameters and variables could influence carbon sequestration and throw light on their relationships. The aim of this study is to assess the role of abiotic variables, chemical elements and stand parameters in soil carbon sequestration, and clarify which of these could affect soil organic carbon (SOC) content in the surface mineral horizon in Norway spruce and European beech stands in Czech Republic. We analyzed 81 monitoring plots within pure and mixed stands of spruce and beech with different degrees of forest naturalness. In each monitoring plot, SOC content, chemical elements (content of bound forms of oxides: tFe, tAl, tCa, tMg, tK, tMn, tP, tN) and related variables (BS, pH, C/N) were measured. The effect of these variables, including abiotic variables (elevation, temperature, precipitation, duration of growing season and soil group) on SOC content was tested, and differences between represented stands (natural vs. unnatural, pure vs. mixed, spruce vs. beech) were analyzed. The results showed that elevation has a positive relationship to SOC content. Of the studied chemical elements and related variables, only tN content was significantly related to SOC content. A positive relationship was also demonstrated between forest naturalness and SOC content. The highest SOC and tN contents were observed in pure natural Norway spruce stands, which likely play a very important role in SOC sequestration. In the context of the current issue of unnatural Norway spruce stands in the Czech Republic, a higher SOC content was found in mixed natural European beech stands than in either pure or mixed unnatural Norway spruce stands. Therefore, replacing the unnatural Norway spruce stands in the study area with mixed natural European beech stands could represent a viable alternative to current forest management in terms of soil carbon sequestration, especially in the context of global climate change and spruce dieback.

Keywords: Soil Organic Carbon (SOC), Carbon Sequestration, Forest Soil, Norway Spruce, European Beech, Chemical Elements

iForest 14 (4): 320-328 (2021) - doi: 10.3832/ifor3654-014
https://iforest.sisef.org/contents/?id=ifor3654-014

Research Articles: Study on the chemical composition of teak wood extracts in different organic solvents

2021-07-09

Colbu DE, Sandu I, Vasilache V, Earar K, Paraschiv ED, Sandu IG, Iliescu Bulgaru D, Sandu AV

STUDY ON THE CHEMICAL COMPOSITION OF TEAK WOOD EXTRACTS IN DIFFERENT ORGANIC SOLVENTS

Abstract: Teak wood (Tectona grandis Linn F.) is known for its high natural resistance to attack by microorganisms. For this reason, teak wood is used for restoration works. This paper provides an assessment of the extraction capacity of various organic solvents and the chemical and physical-structural characteristics of extracts of teak wood with an age of 40 years. On the basis of literature data, we selected the solvents with potential synergetic activity in preservation treatments. For this purpose we used the SEM-EDX and GC+MS methods, assisted by computerized processing software, and corroborated the data obtained from these two instrumental techniques.

Keywords: Teak Wood, Composition, Organic Solvents, Extracts, SEM-EDX, GC+MS

iForest 14 (4): 329-336 (2021) - doi: 10.3832/ifor3717-014
https://iforest.sisef.org/contents/?id=ifor3717-014

Research Articles: Growth and physiological acclimation to shade in young plants of Adesmia bijuga Phil., a critically endangered species in central Chile

Yáñez MA, Gómez P, Gajardo J, Espinoza S — 2021-07-01

Yáñez MA, Gómez P, Gajardo J, Espinoza S

GROWTH AND PHYSIOLOGICAL ACCLIMATION TO SHADE IN YOUNG PLANTS OF ADESMIA BIJUGA PHIL., A CRITICALLY ENDANGERED SPECIES IN CENTRAL CHILE

Abstract: Adesmia bijuga Phil. is an endemic and endangered shrub species of central Chile. Its potential shade intolerance is one of the leading hypotheses for its vigor loss when the species grows beneath closed canopies. The objective of this study was to assess the growth and physiological acclimation to the shade of young plants of A. bijuga. A nursery experiment was established with three light levels based on the interception of photosynthetic active radiation (PAR) (TRT0: control at full sun; TRT60: 60% shaded; TRT90: 90% shaded), and maintained for 71 days during the summer season. Growth and leaf morpho-physiological responses were evaluated at the beginning, at the middle, and at the end of the experiment. The shading treatment increased plant height (H), live crown percentage (Lcrown), and specific leaf area (SLA) compared to the control treatment at full sun. However, light-saturated photosynthetic rate (Amax), dark respiration rate (Rd), and light compensation point (Γi) were higher in TRT60 than in the other treatments, while no differences were found among treatments for the apparent quantum yield (α). At this stage of plant development, our results suggest high acclimation plasticity of A. bijuga to light levels; however, a semi-shade environment (i.e., TRT60) favored a better performance of the species.

Keywords: Adesmia bijuga, Shade Tolerance, Photosynthesis, Light Acclimation, Forest Restoration

iForest 14 (4): 307-312 (2021) - doi: 10.3832/ifor3640-014
https://iforest.sisef.org/contents/?id=ifor3640-014

Research Articles: Improving dimensional stability of Populus cathayana wood by suberin monomers with heat treatment

Zhang R, Ma E — 2021-07-01

Zhang R, Ma E

IMPROVING DIMENSIONAL STABILITY OF POPULUS CATHAYANA WOOD BY SUBERIN MONOMERS WITH HEAT TREATMENT

Abstract: This paper presents a wood modification method using renewable and non-toxic suberin monomers (SMs) under heat treatment to improve dimensional stability of wood from fast-growing species. Specimens of poplar (Populus cathayana) wood were impregnated with SMs and then subjected to heat treatment at 180°C for two hours. The untreated wood (Control), suberin monomers impregnated wood (Sub) and suberin monomers impregnated wood with heat treatment (Sub 180°C) were analyzed by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and Fourier transform infrared spectroscopy (FTIR). The hygroscopicity and dimensional stability of modified wood were evaluated. The results showed that SMs in the treated wood were located in the cell lumen of fibers and vessels, as well as in the cell wall which was bulked. The dimensional stability of SMs modified wood was improved, and this enhancement became more pronounced by a combination with heat treatment. The anti-swelling efficiency of Sub and Sub 180°C treatments were 30.0% and 49.6%, respectively. The presented results showed potential of SMs treatment to develop an effective modification approach and improve dimensional stability of wood of fast-growing species, as well as to promote the reuse of suberin from the bark.

Keywords: Poplar, Wood Modification, Suberin, Dimensional Stability, Heat Treatment

iForest 14 (4): 313-319 (2021) - doi: 10.3832/ifor3684-014
https://iforest.sisef.org/contents/?id=ifor3684-014

Research Articles: Could cattle ranching and soybean cultivation be sustainable? A systematic review and a meta-analysis for the Amazon

da Silveira Bueno R, Marchetti L, Cocozza C, Marchetti M, Salbitano F — 2021-06-08

da Silveira Bueno R, Marchetti L, Cocozza C, Marchetti M, Salbitano F

COULD CATTLE RANCHING AND SOYBEAN CULTIVATION BE SUSTAINABLE? A SYSTEMATIC REVIEW AND A META-ANALYSIS FOR THE AMAZON

Abstract: Tropical forests are being destroyed to make space for agricultural activities with the assumption that they are required to feed the growing global population. Consequently, more sustainable practices are needed to guarantee food security and environmental protection of highly threatened natural biodiversity hotspots like the Amazon rainforest. Cattle ranching and soybean cultivation are by far the greater drivers of land use change and deforestation in the Amazon region. We performed a systematic review of papers related to these two main drivers and a meta-analysis on the effects of sustainable practices on different ecosystem services. The results of the review highlight a large concern about the negative impacts of cattle ranching and soybean crops on the ecosystem dynamics and functionality of the Amazon biome, in addition to the clear relationship with deforestation. Another relevant finding is the large gap in empirical research concerning the effects of sustainable practices on different ecosystem services. Such a gap is evident since only 13 studies from the initial database met the requirements for a meta-analysis. Of the 171 comparisons between the ecosystem services provided in conventional land-uses and those adopting sustainable practices, the overall model indicated a non-significant effect, although the results were heterogeneous. Crop yield and herbage biomass were negatively affected, while livestock productivity, soil organic carbon, soil fertility and woody biomass were positively affected. Also, the six sustainable practices evaluated showed different outcomes, from a predominance of positive effects in silvopastoral systems, to a predominance of negative effects on agrosilvicultural systems. Our systematic review and meta-analysis indicate that cattle ranching and soybean cultivation can indeed be conducted in a more sustainable way, enhancing the provision of ecosystem services while avoiding deforestation. In turn, our results also highlight the lack of empirical data and the need to standardize the methodologies used to deeply assess the effects of such practices. In conclusion, we suggest a way to advance research into the real effects of sustainable practices aimed at reducing the negative impacts of cattle ranching and soybean crops in the Amazon.

Keywords: Tropical Forest, Agroforestry, Ecosystem Services, Silvopastoral Systems, Sustainable Practices, Cattle, Soybean

iForest 14 (3): 285-298 (2021) - doi: 10.3832/ifor3779-014
https://iforest.sisef.org/contents/?id=ifor3779-014

Research Articles: Age and thinning effects on elemental composition of Pinus pinaster and Pinus radiata needles

Gómez-Rey MX, Couto-Vázquez A, González-Prieto SJ — 2021-06-08

Gómez-Rey MX, Couto-Vázquez A, González-Prieto SJ

AGE AND THINNING EFFECTS ON ELEMENTAL COMPOSITION OF PINUS PINASTER AND PINUS RADIATA NEEDLES

Abstract: The information about the impacts of thinning on the availability of micro-nutrients, as well as macro-nutrients other than N, P and K, is still scarce. We assessed the changes in the concentrations of 12 elements (Al, B, Ca, Cu, Fe, K, Mg, Mn, N, Na, P and Zn) with needle age (current year or 1-year-old) and three early thinning treatments in two of the most widely distributed pines in SW Europe: P. pinaster and P. radiata. Four treatments were setup in triplicate: control (C), light thinning (LT), heavy thinning (HT) and selection thinning of dominant trees (ST), with 0%, 10%, 20% and 20% of total basal area removed, respectively. Needle δ15N varied little with needle age and most thinning treatments in both species, but ST triggered an increase of N in P. pinaster needles. Needle Ca and Na increased with age, but were unaffected by treatment. Foliar K, Zn and Cu decreased with age in both species and increased with ST only in P. pinaster. Jointly considering all treatments, there was no needle age effect on Mn concentration, neither in P. radiata nor in P. pinaster, but in the latter species Mn levels increased with age in the selection thinning plots. There were significant thinning effects on Mn levels in both P. pinaster (ST>C) and P. radiata (HT > LT, ST). Foliar Fe and Al concentration increased with age in both pines; the former increased with ST only in P. pinaster while the latter was affected by thinning only in current year needles and without a clear tendency. Neither age nor treatment effects on needle Mg and B were found, while for P needle age had a significant effect only in P. pinaster.

Keywords: Leaves, Macro-nutrient, Micro-nutrient, Management, Pines

iForest 14 (3): 299-306 (2021) - doi: 10.3832/ifor3575-014
https://iforest.sisef.org/contents/?id=ifor3575-014

Research Articles: Validation of visual and machine strength grading for Italian beech with additional sampling

Brunetti M, Aminti G, Nocetti M, Russo G — 2021-05-29

Brunetti M, Aminti G, Nocetti M, Russo G

VALIDATION OF VISUAL AND MACHINE STRENGTH GRADING FOR ITALIAN BEECH WITH ADDITIONAL SAMPLING

Abstract: The typical variability of wood properties, higher than for other construction materials, requires a thorough knowledge of its mechanical performance. To make the use of wooden structural products safe and at the same time efficient, a proven methodology for the selection of the raw material is also crucial. As a general rule, the initial sampling is of vital importance to develop effective strength grading processes, but it is rarely verified with additional samples, besides those already included during the development of the grading procedure itself. Here, a new source of sawn timber was collected to verify the original sampling and to validate the visual and machine strength grading early developed for Italian beech. The new pieces were graded, destructively tested and the characteristic values of the graded material were calculated. The dispersion of the new data was found to be entirely included in that of the original data, proving an effective sampling of the resource variability. The correlations between properties were very similar comparing the original and the new sample, with the exception of the correlations between the dynamic modulus of elasticity and both bending strength and stiffness, which were lower in the new sample. The characteristic values of the graded new material were generally higher than the characteristics values of the corresponding strength classes as tabled in the technical standard. Only for one grade in the machine grading the strength reached 98.9% the class value, anyhow above the 90% required by the procedure of the checking of existing settings in a particular location, as provided by the related standard. In conclusion, the earlier development of the strength grading of Italian beech confirmed to be correct and safe.

Keywords: Hardwood, Visual Grading, Machine Grading, Structural Timber

iForest 14 (3): 260-267 (2021) - doi: 10.3832/ifor3649-014
https://iforest.sisef.org/contents/?id=ifor3649-014

Research Articles: Thermo-modified native black poplar (Populus nigra L.) wood as an insulation material

Todaro L, Liuzzi S, Pantaleo AM, Lo Giudice V, Moretti N, Stefanizzi P — 2021-05-29

Todaro L, Liuzzi S, Pantaleo AM, Lo Giudice V, Moretti N, Stefanizzi P

THERMO-MODIFIED NATIVE BLACK POPLAR (POPULUS NIGRA L.) WOOD AS AN INSULATION MATERIAL

Abstract: Extensive research projects have been carried out on thermal modification of wood material, yet thermal properties of thermally modified poplar wood have not been comprehensively investigated. Black poplar (Populus nigra L.) is a Eurasian species native to Italy which is rarely used for the production of high-performance products, though it is one of the least expensive hardwoods on the market. To explore alternative applications of poplar wood such as building facade or fire resistance materials, reliable data of thermal behaviour of thermally modified wood at high temperatures are needed. In this work, the thermal behaviour of native black poplar wood after thermal modification at different temperatures (180 °C, 200 °C and 220 °C) was analyzed. Thermal conductivity, thermal diffusivity and porosity were measured on poplar wood boards, as well as mass loss and wood color changes after heat treatment were quantified. Thermal conductivity of wood samples showed significant changes after treatment at 200 and 220 °C, but not at 180 °C. Wood porosity showed significant differences with the control when the samples were modified at a temperature of 220 °C. Increasing color differences were observed in wood samples by increasing the thermal modification temperature. Also, the mass loss of wood samples increased and equilibrium moisture content significantly dropped down after thermal modification. Our results showed that the use of thermally-modified black poplar wood could be considered as a viable alternative to chemically treated wood products for specific applications where high insulation is needed, such as saunas or windows, and for façades elements.

Keywords: Thermal Modification, Poplar, Insulation, Thermal Properties

iForest 14 (3): 268-273 (2021) - doi: 10.3832/ifor3710-014
https://iforest.sisef.org/contents/?id=ifor3710-014

Research Articles: Hardness and contact angle of thermo-treated poplar plywood for bio-building

Zanuttini R, Negro F, Cremonini C — 2021-05-29

Zanuttini R, Negro F, Cremonini C

HARDNESS AND CONTACT ANGLE OF THERMO-TREATED POPLAR PLYWOOD FOR BIO-BUILDING

Abstract: The interest towards poplar cultivation and its wood has recently been growing in Italy, where the use of timber and wood-based materials in construction is increasing as well. Poplar plywood, with a national production of around 270.000 m3 in 2017, is a key product for the Italian wood sector, and currently is destined for several applications as component for furniture and motorhomes. Previous research has shown that thermal treatment can be effectively applied to poplar plywood in order to make it suitable to the requirements of new end-uses. The present study aims to widen the knowledge of the effects of thermal treatment on poplar plywood. With this purpose, 7-layered, 12-mm thick plywood bonded with urea-melamine-formaldehyde (UMF) resin was thermally treated for 2 h at 170, 190 and 210 °C through the Termovuoto® process. The treatment aimed to improve the dimensional stability and durability against fungal decay. The process was set at lower temperature and shorter time than those of many thermal treatments commonly used in practice in order to limit the reduction in mechanical properties and to maintain an adequate bonding quality. The above properties were already verified by previous research, whereas in this study Brinell hardness and contact angle of treated panels were investigated as relevant for several end-uses that can be prospected in building and in outdoor environments. Brinell hardness decreased from 10.8 to 8.3 N mm-2 and contact angle increased from 75.8° to 103.6°. Overall, treatment at 190 °C seems the most suitable to induce balanced modifications in the panels. From a technical point of view, these appear ready to enter the market, for instance for use in exterior claddings, partitions and outdoor flooring.

Keywords: Brinell Hardness, Contact Angle, Plywood, Poplar, Thermo-treatment

iForest 14 (3): 274-277 (2021) - doi: 10.3832/ifor3662-014
https://iforest.sisef.org/contents/?id=ifor3662-014

Research Articles: Estimation of forest leaf area index using satellite multispectral and synthetic aperture radar data in Iran

Vafaei S, Fathizadeh O, Puletti N, Fadaei H, Baqer Rasooli S, Vaglio Laurin G — 2021-05-29

Vafaei S, Fathizadeh O, Puletti N, Fadaei H, Baqer Rasooli S, Vaglio Laurin G

ESTIMATION OF FOREST LEAF AREA INDEX USING SATELLITE MULTISPECTRAL AND SYNTHETIC APERTURE RADAR DATA IN IRAN

Abstract: Different satellite datasets, including multispectral Sentinel 2 and synthetic aperture radar Sentinel 1 and ALOS2, were tested to estimate the Leaf Area Index (LAI) in the Zagros forests, Ilam province, in Iran. Field data were collected in 61 sample plots by hemispherical photographs, to train and validate the LAI estimation models. Different satellite data combinations were used as input in regression models built with the following algorithms: Multiple Linear Regression, Random Forests, and Partial Least Square Regression. The results indicate that Leaf Area Index can be best estimated using integrated ALOS2 and Sentinel 2 data; these inputs generated the model with higher accuracy (R2 = 0.84). The combination of a single band and a vegetation index from Sentinel 2 also led to successful results (R2 = 0.81). Lower accuracy was obtained when using only ALOS 2 (R2 = 0.72), but this dataset is helpful where cloud coverage affects optical data. Sentinel 1 data was not useful for LAI prediction. The optimal model was based on the traditional Multiple Linear Regression algorithm, using a preliminary input selection step to exclude multicollinearity effects. To avoid this step, the use of Partial Least Square Regression may be an alternative, as this algorithm was able to produce estimates similar to those obtained with the best model.

Keywords: Leaf Area Index, Sentinel 2, ALOS 2, Forest Monitoring

iForest 14 (3): 278-284 (2021) - doi: 10.3832/ifor3633-014
https://iforest.sisef.org/contents/?id=ifor3633-014

Research Articles: Intra-annual tree growth responds to micrometeorological variability in the central Amazon

Antezana-Vera SA, Marenco RA — 2021-05-21

Antezana-Vera SA, Marenco RA

INTRA-ANNUAL TREE GROWTH RESPONDS TO MICROMETEOROLOGICAL VARIABILITY IN THE CENTRAL AMAZON

Abstract: Intra-annual distribution of precipitation in central Amazonia leads to a short mild dry season, which is associated with an increase in irradiance and temperature and a decline in relative humidity; however, the independent effect of each individual climatic variable on tree growth is still under investigation. The objective of this study was to determine how tree growth (inferred from radial stem increment) responds to monthly variations of micrometeorological variables in the central Amazon. During five years (2013-2017) we measured tree growth in 51 trees from nine species and, above the forest canopy, collected environmental data, such as photosynthetically active radiation (PAR), air temperature (T), precipitation, air relative humidity (RH), air vapor pressure deficit (VPD), reference evapotranspiration (ETo), and soil water content (SWC). We used principal component regression to evaluate the effect of micrometeorological variability on tree growth. Mean tree growth across species was responsive to variations in almost all the micrometeorological variables examined, with the exception of mean and minimum temperature, maximum RH, and minimum VPD. Mean tree growth across species increased with increasing precipitation, RHmean, RHmin and SWC, while it decreased with increasing PAR, Tmax, and ETo. It was also shown that an increase in VPDmean and VPDmax has a negative effect on tree growth. These results contribute to improve our understanding of effect of climate variability on tree growth, and shed light on the potential effect of severe droughts in the central Amazon.

Keywords: Atmospheric Evaporative Demand, Tropical Rainforest, Wood Density

iForest 14 (3): 242-249 (2021) - doi: 10.3832/ifor3532-014
https://iforest.sisef.org/contents/?id=ifor3532-014

Research Articles: Factors affecting the quantity and type of tree-related microhabitats in Mediterranean mountain forests of high nature value

2021-05-21

Marziliano PA, Antonucci S, Tognetti R, Marchetti M, Chirici G, Corona P, Lombardi F

FACTORS AFFECTING THE QUANTITY AND TYPE OF TREE-RELATED MICROHABITATS IN MEDITERRANEAN MOUNTAIN FORESTS OF HIGH NATURE VALUE

Abstract: Tree-related microhabitats (hereafter TreMs) are structures occurring on trees, such as rot holes, cavities, large nests, mould, fruiting bodies and mycelia of decomposer fungi. TreMs have been widely recognized as important substrates and structures useful for biodiversity conservation in forest ecosystems, and they can be used as indicators for describing and monitoring forest naturalness. However, most studies on the occurrence of TreMs have been mainly done in forest ecosystems of Central Europe, while less research has been conducted in Mediterranean mountain forests. In this study, we investigated the diversity and abundance of 23 types of TreMs on living trees and on deadwood in seven Mediterranean mountains unmanaged forests located in the Apennines (Italy). The abundance of TreMs was evaluated by counting the number of TreMs per tree, while the diversity of TreMs was evaluated by means of the Shannon-Wiener index. We focused on the relationships between diversity and abundance of TreMs, and tree size (e.g., diameter, height, volume), and the time since the last harvest. Among the investigated stands, 2612 living trees, 457 standing dead trees and snags, and 1247 lying deadwood pieces were analysed. For living trees, a generalized linear mixed model was applied to test the effect of several variables on the abundance of TreMs per tree. Diameter at breast height (DBH) of tree stems influenced the abundance and diversity of TreMs. The time since the last harvest also significantly affected the probability that TreMs could be formed in a long-term perspective. The interaction of the predictors “DBH2” and “Years since the last harvest” generated a better model than the one in which the two variables were kept separate. Indeed, these two factors together would better represent the transition of a previously managed forest to a more natural state over time. This study might provide useful information to land managers committed to forestry practices towards sustainable management and biodiversity conservation, especially referring to survey and inventory of forests of high nature value.

Keywords: Biodiversity Indicators, Forest Structure, Old-growth Forests, Tree Microhabitats, Woody Debris

iForest 14 (3): 250-259 (2021) - doi: 10.3832/ifor3568-014
https://iforest.sisef.org/contents/?id=ifor3568-014

Research Articles: Are Mediterranean forest ecosystems under the threat of invasive species Solanum elaeagnifolium?

Formozis G, Tsakaldimi M, Ganatsas P — 2021-05-10

Formozis G, Tsakaldimi M, Ganatsas P

ARE MEDITERRANEAN FOREST ECOSYSTEMS UNDER THE THREAT OF INVASIVE SPECIES SOLANUM ELAEAGNIFOLIUM?

Abstract: Solanum elaeagnifolium Cav. is one of the most invasive plant species worldwide that colonizes crops and human disturbed lands, while it appears at the edge of forest ecosystems. Its control still remains an unsolved problem around the world. Understanding its distribution under predicted climate change, could contribute to an effective management and conservation of ecosystems in the future. This research was conducted in order to investigate the capacity of this species to invade Mediterranean forest ecosystems, and if the allelopathy effects of forest tree species could control its regeneration, thus contributing to a natural and biological management practice aimed to prevent the species from pervading into Mediterranean forest ecosystems. Results showed that S. elaeagnifolium can establish itself outside and along the forest edges, but not in a typical forest environment. The leaf extracts of Pinus brutia, Cupressus sempervirens, Quercus coccifera and Quercus pubescens significantly inhibited the germination of S. elaeagnifolium. Root regenerative ability of the cuttings was also significantly affected by the leaf extract treatments. P. brutia leaf extract had significantly the highest inhibitory activity on root regenerative ability of the species. Despite the promising findings of this study, absence of S. elaeagnifolium in Mediterranean forest ecosystems can be attributed to a combination of factors. In the context of climate change, especially in hot and dry Mediterranean areas, and the expected increase of forest disturbances (e.g., fires), the findings of the study could contribute towards the restriction of this invasive alien species by an appropriate management of forest ecosystems.

Keywords: Alien Species, Allelopathy, Forest Conservation, Plant Invasion, Weed Control

iForest 14 (3): 236-241 (2021) - doi: 10.3832/ifor3706-014
https://iforest.sisef.org/contents/?id=ifor3706-014

Commentaries & Perspectives: JRC study on harvested forest area: resolving key misunderstandings

Grassi G, Cescatti A, Ceccherini G — 2021-05-07

Grassi G, Cescatti A, Ceccherini G

JRC STUDY ON HARVESTED FOREST AREA: RESOLVING KEY MISUNDERSTANDINGS

Abstract: A recent study on forest harvest in the EU (Ceccherini et al. 2020) reported a strong increase in clear-cut harvested area in recent years, based on remote sensing information. This triggered a heated debate and many critical comments. Apart from several fair and constructive criticisms, which were welcome, we found that some comments have been either not based on evidence or affected by serious misunderstandings. Here we clarify some technical aspects that were omitted or misrepresented in the public debate. Overall, the original study used in a scientifically correct way the best information available at that time. After the study was published, a previously undocumented inconsistency in the time series emerged in the original dataset used. After correcting for this inconsistency, updated results confirm an increase in clear-cut harvested area, but not as abrupt as originally reported. Contrary to what many critics say, this information should be seen as complementing and not necessarily contradicting country statistics, because the latter typically refer to total harvest (including thinning, etc.) and not clear-cut only. Finally, it should not be overlooked that the main aim of the original study was to offer a vision for integrating satellite data into the monitoring of forest resources. This was achieved: the JRC study showed the potential (and limitations) for high-resolution satellite maps to track the temporal evolution of clear-cut forest harvest in EU.

Keywords: Harvested Forest Area, Remote Sensed Datasets, Global Forest Change (GFC), High-Resolution Satellite Maps

iForest 14 (3): 231-235 (2021) - doi: 10.3832/ifor0059-014
https://iforest.sisef.org/contents/?id=ifor0059-014

Research Articles: Is there an effect of storage depth on the persistence of silver birch (Betula pendula Roth) and rowan (Sorbus aucuparia L.) seeds? A seed burial experiment

Tiebel K, Huth F, Wagner S — 2021-05-06

Tiebel K, Huth F, Wagner S

IS THERE AN EFFECT OF STORAGE DEPTH ON THE PERSISTENCE OF SILVER BIRCH (BETULA PENDULA ROTH) AND ROWAN (SORBUS AUCUPARIA L.) SEEDS? A SEED BURIAL EXPERIMENT

Abstract: Sorbus aucuparia L. (rowan) and Betula spp. (birch) are the most common of the early successional pioneer tree species in central Europe with the ability to form a soil seed bank. Little is known about the reasons for the high variations observed in the persistence in the soil of rowan and birch seeds. The objective of this study was to assess the ability of buried birch and rowan seeds to form short-term persistent soil seed banks and to analyse the influence of burial depth on seed persistence. An artificial seed burial experiment was initiated to study the persistence of birch seeds and rowan seeds, with and without pulp, stored at depths of 2, 5 and 10 cm in mineral soil over 2.5 years. The predicted maximum storability periods for buried birch seeds was 13 years, compared to 4.5 years for rowan seeds with pulp and 3.5 years without pulp. The lower storage capacity of rowan seeds was demonstrated by germinations in the darkness within soil of 3-22% of seeds without pulp and 4-48% of seeds with pulp. Germination percentages of birch and rowan with and without pulp did not differ between depths. Only burial duration had an effect for either tree species. Birch and rowan seeds are able to form short-term persistent soil seed banks. Birch accumulates a seed reserve in the soil over time, until a change in conditions conducive to germination occurs, while rowan seeds germinate promptly after overcoming seed dormancy. The pulp provides no benefits in relation to the persistence of rowan seeds; rather, it appears to act as a physical inhibitor of germination. Therefore, annual input of fresh seeds is required for the success of rowan. Seed input every few years seems sufficient to guarantee a minimum number of viable birch seeds.

Keywords: Soil, Propagule Bank, Seed Longevity, Germination Within Soil, Pioneer Trees, Dormancy

iForest 14 (3): 224-230 (2021) - doi: 10.3832/ifor3685-014
https://iforest.sisef.org/contents/?id=ifor3685-014

Editorials: Obituary: Ervedo Giordano, silviculturalist and forest ecologist from the Mediterranean, open to the world and to international forestry

Scarascia Mugnozza G — 2021-05-05

Scarascia Mugnozza G

OBITUARY: ERVEDO GIORDANO, SILVICULTURALIST AND FOREST ECOLOGIST FROM THE MEDITERRANEAN, OPEN TO THE WORLD AND TO INTERNATIONAL FORESTRY

Abstract: Ervedo Giordano passed away in Rome on April 24, 2021. This note describes some of his major scientific contributions to research in silviculture and forest ecology, and sketches out the remarkable personality and character traits that he displayed throughout his life.

Keywords: Silviculture, Forest Ecology, Mediterranean Forests, Italy

iForest 14 (3): 221-223 (2021) - doi: 10.3832/ifor0060-014
https://iforest.sisef.org/contents/?id=ifor0060-014

Research Articles: Determination of differences in temperature regimes on healthy and bark-beetle colonised spruce trees using a handheld thermal camera

Majdák A, Jakuš R, Blaženec M — 2021-05-02

Majdák A, Jakuš R, Blaženec M

DETERMINATION OF DIFFERENCES IN TEMPERATURE REGIMES ON HEALTHY AND BARK-BEETLE COLONISED SPRUCE TREES USING A HANDHELD THERMAL CAMERA

Abstract: In this study, we compared the daily temperature regimes of healthy uninfected trees in the interior of a forest stand and at the fresh forest edge with infested trees at the forest edge in an area affected by a bark beetle outbreak. We estimated the potential of a handheld thermal camera for early identification of bark-beetle infested trees. We show that infested trees have significantly higher trunk temperatures than uninfested trees, which is more visible on the shine side of the trunk, and we report the differences in temperature between the shine and shadow sides. The differences are more noticeable on a warm, bright, and sunny day than on cold and cloudy day. The different intensity of solar radiation does not affect the distinction between infested and uninfested trees. The handheld thermal camera shows potential for identifying bark-beetle infested trees by scanning tree trunks on bright sunny days.

Keywords: Bark-beetle Infested Trees, Handheld Thermal Camera, Incoming Solar Radiation, Norway Spruce, Solar Radiation Modelling, Temperature Differences

iForest 14 (3): 203-211 (2021) - doi: 10.3832/ifor3531-014
https://iforest.sisef.org/contents/?id=ifor3531-014

Research Articles: Density, extractives and decay resistance variabilities within branch wood from four agroforestry hardwood species

2021-05-02

Terrasse F, Brancheriau L, Marchal R, Boutahar N, Lotte S, Guibal D, Pignolet L, Candelier K

DENSITY, EXTRACTIVES AND DECAY RESISTANCE VARIABILITIES WITHIN BRANCH WOOD FROM FOUR AGROFORESTRY HARDWOOD SPECIES

Abstract: Agroforestry practices like pruning trees to control the light flux to crops produce every year a large volume of branches which is valorized by farmers as mulching or energy fuel. However, according to the literature, the wood of branches shows higher rates of polyphenols than stem wood and this can open some new perspectives for branch exploitation. In this study, the wood properties (density, mechanical properties, extractive content and decay resistance) were determined on branches of different sizes from oak, chestnut, poplar and walnut trees collected in two agroforestry systems. These properties were evaluated according to the wood age and the sampling position along the radial and longitudinal axes of the branch. All samples were analyzed by NIR-Spectroscopy and a predicting model aimed to assess the branch wood properties has been developed. Wood characteristics largely vary between species and do not exactly follow the same trends from one species to another. Overall, hardwood density of branches is similar to that of trunks, the content in wood extractives follows similar evolutions, and the decay resistance of branch wood does not seem to be really impacted by its position along the branch. Reliable NIRS models were built to easily predict the wood density and extractives content of agroforestry branches. The extractives content and the decay resistance of branch hardwood appear to be substantially lower than those of trunks, which suggests a non-suitability of branch wood for developing high-valued green chemistry.

Keywords: Agroforestry, Branches, NIR-Spectrometry, Wood Quality

iForest 14 (3): 212-220 (2021) - doi: 10.3832/ifor3693-014
https://iforest.sisef.org/contents/?id=ifor3693-014

Research Articles: Mid-rotation fertilization and liming of Pinus taeda: growth, litter, fine root mass, and elemental composition

Adam WM, Rodrigues VDS, Magri E, Motta ACV, Prior SA, Moraes Zambon L, Lima RLD — 2021-04-24

Adam WM, Rodrigues VDS, Magri E, Motta ACV, Prior SA, Moraes Zambon L, Lima RLD

MID-ROTATION FERTILIZATION AND LIMING OF PINUS TAEDA: GROWTH, LITTER, FINE ROOT MASS, AND ELEMENTAL COMPOSITION

Abstract: Forest floor litter can influence biogeochemical cycling and root growth in Pinus taeda systems, especially on low soil fertility sites. The impact of fertilization and liming on forest floor litter (quantity, elemental composition and root presence) was evaluated in a Pinus taeda stand in southern Brazil. A nutrient omission experiment was initiated in November 2008 on an 11 year-old Pinus taeda plantation. The experiment was a randomized block design with seven treatments and four blocks. The treatments were: complete (macro + micro + lime); minus macronutrients; minus micronutrients; minus K; minus Zn; minus lime; and control. In 2012, forest floor litter samples were collected, divided by layer (new litter, old litter, coarse fragmented forest layer > 2mm, fine fragment forest floor < 2mm, and fine roots) and analyzed for concentrations of Na, Al, and total nutrients. Results indicated that lime increased Ca and Mg concentrations, reduced Al toxicity, and improved fine root growth. An increase in fine roots was observed in treatments without K. There were large increases in Fe and Al as a function of litter age and increased Mn in fragmented litter when lime was applied. There was little variation in forest floor litter accumulation in all treatments. Elemental abundance was C>N>Fe>P>Ca>K>Mg>Mn under control conditions and C>N>Ca>Mg>P>Fe>Mn>K for the complete treatment. Occurrence of needle chlorosis, similar to that reported for Mg, and low growth under lime omission indicate that Mg was a major factor limiting growth. Fertilization and liming affected the bio-cycling of nutrients, Al toxicity, and root growth.

Keywords: Nutrient Concentration, Litter, Ca:Al Ratio, Forest Management

iForest 14 (2): 195-202 (2021) - doi: 10.3832/ifor3626-014
https://iforest.sisef.org/contents/?id=ifor3626-014

Research Articles: Developing stand transpiration model relating canopy conductance to stand sapwood area in a Korean pine plantation

Park J, Cho S, Moon M, Ryu D, Kim HS — 2021-04-14

Park J, Cho S, Moon M, Ryu D, Kim HS

DEVELOPING STAND TRANSPIRATION MODEL RELATING CANOPY CONDUCTANCE TO STAND SAPWOOD AREA IN A KOREAN PINE PLANTATION

Abstract: With increasing concern for forest water use and anthropogenic alteration of forest structures, understanding the effects of structural changes in forests on transpiration is important. Our aim is to develop a stand transpiration model relating canopy conductance with stand sapwood area (SA) and environmental conditions for assessing the interannual variation in stand transpiration. The stand transpiration model is developed based on multiplicative empirical Gc estimations at eight Korean pine stands with different SAs. The model integrated the response of stomatal conductance to various environmental variables as vapor pressure deficit (D), photosynthetic active radiation (Q), air temperature (Ta), and soil water content (θ). The reference Gc (Gc at D=1kPa) and stomatal sensitivity to D was found to have a significant relationship with the SA, whereas other parameters like stomatal sensitivity to Q or Ta did not show significant relationships with it. The Gc model successfully reproduced changes in stand transpiration with changes in SA and climatic conditions. As this model uses SA, a simple and easily measurable structural variable, it can be easily applied to other Korean pine forests and can help estimate the spatial and temporal variations in stand transpiration.

Keywords: Sapwood Area, Canopy Conductance, Stand Transpiration, Empirical Model

iForest 14 (2): 186-194 (2021) - doi: 10.3832/ifor3291-014
https://iforest.sisef.org/contents/?id=ifor3291-014

Research Articles: The impact of land use on future water balance - A simple approach for analysing climate change effects

Herceg A, Kalicz P, Gribovszki Z — 2021-04-13

Herceg A, Kalicz P, Gribovszki Z

THE IMPACT OF LAND USE ON FUTURE WATER BALANCE - A SIMPLE APPROACH FOR ANALYSING CLIMATE CHANGE EFFECTS

Abstract: Regional climate change projections for Europe agree in predicting a statistically significant warming in all seasons. The most significant climate change effect is its impact on water cycle through altering precipitation patterns and evapotranspiration processes at multiple scales. The anticipated changes in the distribution and precipitation amounts together with continuously increasing temperatures may induce a higher rate of water consumption in plants, which can generate changes in soil moisture, groundwater, and the water cycle. Thus, climate change can cause changes in the water balance equations structure. A Thornthwaite-type monthly step water balance model was established to compare the water balance in three different surface land cover types: (i) a natural forested area; (ii) a parcel with mixed surface cover; (iii) an agricultural area. The key parameter of the model is the water storage capacity of the soil. Maximal rooting depth of the given area is also determinable during the calibration process using actual evapotranspiration (AET) and soil physical data. The locally calibrated model was employed for assessing future AET and soil moisture of selected land cover types using data from four bias-corrected regional climate models. The projections demonstrate increasing actual evapotranspiration values in each surface cover type at the end of the 21st century. Regarding the 10th percentile minimum soil moisture values, the forested area displayed an increasing trend, while the agricultural field and mixed parcel showed a strong decrease. The 30-year monthly means of evapotranspiration shows the maximum values in June and July, while the minimum soil moisture in September. Water stress analysis indicates water stress is expected to occur only in the agricultural field during the 21st century. The comparison of the three surface covers reveals that forest has the greatest soil water storage capacity due to the highest rooting depth. Thus, according to the projections for 21st century, less water stress is predicted to occur at the forested area compared to the other two surface covers which shows shallow rooting depth.

Keywords: Water Balance, Climate Change, Plant Available Water, Evapotranspiration, Soil Moisture, Water Stress

iForest 14 (2): 175-185 (2021) - doi: 10.3832/ifor3540-014
https://iforest.sisef.org/contents/?id=ifor3540-014

Review Papers: Perspectives of plantation forests in the sustainable forest development of China

2021-04-09

Farooq TH, Shakoor A, Wu X, Li Y, Rashid MHU, Zhang X, Gilani MM, Kumar U, Chen X, Yan W

PERSPECTIVES OF PLANTATION FORESTS IN THE SUSTAINABLE FOREST DEVELOPMENT OF CHINA

Abstract: Modern forestry is gradually moving towards man-made forests on a large scale. Plantations with advanced forestry system have been introduced with the goal of sustainable forestry development and to enhance social, ecological, and economic benefits. Forest plantations with native and exotic species have been established in China and worldwide with shorter rotation cycles than natural forests. In this paper, we discuss the role and perspectives of plantation forests in the Chinese sustainable forest development, the evolution of various plantation programs, the ecological effects of plantations, and the measures to improve plantation forestry. The Chinese government has given substantial importance to nurturing plantation forest resources through various large scale afforestation programs. In 2019, the total area covered by plantations in China reached 79.54 million ha, with a stock volume of 3.39 billion m³ (59.30 m³ per ha); coniferous forests (26.11 million ha, 32.83%) and broad-leaved forests (26.45 million ha, 33.25%) are the dominant types. Plantations have been primarily distributed in the central and southern parts of the country. Plantations with fast-growing and high-yielding tree species facilitated Chinese afforestation activities and improved the administration of forest production, which effectively boosted the forest industry. Plantation forest resources offer many potential productive, economic, and social advantages, though they are also associated with a loss of biodiversity and climate change makes them likely susceptible to disease and insect attack. Appropriate forest management practices during planning, execution, and maintenance of plantations can contribute to the conservation, promotion, and restoration of biodiversity, with the final aim of attaining a balance between having forest plantations and natural forests.

Keywords: Chinese Fir, Poplar, Eucalyptus, National Forest Inventories of China, Ecological Implications

iForest 14 (2): 166-174 (2021) - doi: 10.3832/ifor3551-014
https://iforest.sisef.org/contents/?id=ifor3551-014

Research Articles: Contrasted growth response of hybrid larch (Larix × marschlinsii), jack pine (Pinus banksiana) and white spruce (Picea glauca) to wood ash application in northwestern Quebec, Canada

Bélanger N, Palma Ponce G, Brais S — 2021-04-06

Bélanger N, Palma Ponce G, Brais S

CONTRASTED GROWTH RESPONSE OF HYBRID LARCH (LARIX × MARSCHLINSII), JACK PINE (PINUS BANKSIANA) AND WHITE SPRUCE (PICEA GLAUCA) TO WOOD ASH APPLICATION IN NORTHWESTERN QUEBEC, CANADA

Abstract: The use of wood ash as a soil amendment in afforestation and reforestation efforts is increasing. While most studies suggest benefits or neutral results on tree growth and survival, a few studies indicate adverse effects. Hybrid larch, jack pine and white spruce were studied at three northwestern Quebec plantation sites after they received wood ash at two application rates. Soil chemical properties, foliar nutrients and seedling growth and mortality were monitored over a period of eight years. The response of soil to ash application was mostly observed in the forest floor and was more pronounced in year 3 than year 8, likely due to the acidifying nature of the boreal soils studied. Jack pine growth increased linearly with wood ash application rates, white spruce growth showed an inconsistent and delayed positive response under the higher application rate, and hybrid larch growth and survival were either increased or decreased under the lower application rate depending of site but decreased at all sites under the higher application rate. The divergence in growth response between tree species underlines a trade-off between species with rapid acquisition of resources (e.g., pine, larch) to species that use more conservative strategies and store nutrients in their tissues for longer periods (e.g., spruce). In the case of hybrid larch, it accumulated larger amounts of Mn in its needles under the higher application rate and thus, the high bioavailability of Mn appears to have been detrimental to its survival and growth. Its higher sensitivity to Mn addition from ash is likely due to its highly acquisitive (nutrients) nature compared to other coniferous species as well as the initial levels of available Mn levels in the soil. The contrasted growth responses reported here under similar growing conditions highlight the importance of identifying suitable species, sites and application rates to maximize the benefits of wood ash amendments for future tree plantations in the boreal forest.

Keywords: Wood Ash, Fertilization, Boreal Forest, Soil Properties, Foliar Nutrition, Tree Growth

iForest 14 (2): 155-165 (2021) - doi: 10.3832/ifor3597-014
https://iforest.sisef.org/contents/?id=ifor3597-014

Research Articles: Are we ready for a National Forest Information System? State of the art of forest maps and airborne laser scanning data availability in Italy

2021-03-23

D’Amico G, Vangi E, Francini S, Giannetti F, Nicolaci A, Travaglini D, Massai L, Giambastiani Y, Terranova C, Chirici G

ARE WE READY FOR A NATIONAL FOREST INFORMATION SYSTEM? STATE OF THE ART OF FOREST MAPS AND AIRBORNE LASER SCANNING DATA AVAILABILITY IN ITALY

Abstract: Forest planning, forest management, and forest policy require updated, reliable, and harmonized spatial datasets. In Italy a national geographic Forest Information System (FIS) designed to store and facilitate the access and analysis of spatial datasets is still missing. Among the different information layers which are useful to start populating a FIS, two are essential for their multiple use in the assessment of forest resources: (i) forest mapping, and (ii) data from Airborne Laser Scanning (ALS). Both layers are not available wall-to-wall for Italy, though different local sources of information potentially useful for their implementation already exist. The objectives of this work were to: (i) review forest maps and ALS data availability in Italy; (ii) develop for the first time a high resolution forest mask of Italy which was validated against the official statistics of the Italian National Forest Inventory; (iii) develop the first mosaic of all the main ALS data available in Italy producing a consistent Canopy Height Model (CHM). An on-line geographic FIS with free access to both layers from (ii) and (iii) was developed for demonstration purposes. The total area of forest and other wooded lands computed from the forest mask was 102.608.82 km2 (34% of the Italian territory), i.e., 1.9% less than the NFI benchmark estimate. This map is currently the best wall-to-wall forest mask available for Italy. We showed that only the 63% of the Italian territory (the 60% of the forest area) is covered by ALS data. These results highlight the urgent need for a national strategy to complete the availability of forest data in Italy.

Keywords: National Datasets, Forest Inventory, Forest Monitoring, Forest Mask, Airborne Laser Scanning, LiDAR

iForest 14 (2): 144-154 (2021) - doi: 10.3832/ifor3648-014
https://iforest.sisef.org/contents/?id=ifor3648-014

Research Articles: Modelling taper and stem volume considering stand density in Eucalyptus grandis and Eucalyptus dunnii

Hirigoyen A, Navarro-Cerrillo R, Bagnara M, Franco J, Requin F, Rachid-Casnati C — 2021-03-16

Hirigoyen A, Navarro-Cerrillo R, Bagnara M, Franco J, Requin F, Rachid-Casnati C

MODELLING TAPER AND STEM VOLUME CONSIDERING STAND DENSITY IN EUCALYPTUS GRANDIS AND EUCALYPTUS DUNNII

Abstract: Eucalyptus grandis and Eucalyptus dunnii are the most planted tree species in Uruguay. Anticipating information about the quantity and quality of wood is important for managing intensive forest plantation. The estimate of merchantable and total wood volume is an essential tool in forest planning and management. The aim of this study was to evaluate four systems of taper and merchantable volume that consisted in a taper, a merchantable volume and a total tree volume function. A modified second-order continuous autoregressive error structure corrected the inherent serial autocorrelation of different observations in one tree. Taper and volume equations were fitted simultaneously after autocorrelation correction by full information maximum likelihood method. The segmented system proposed by Fang et al. (2000) produced the best fit as it explained more than 98% of the taper, merchantable volume and total volume variability for both species. In addition, precision of the segmented system was compared with and without incorporating stand density as a variable. Results of this analysis showed that for E. grandis, the predictive accuracy of the model was improved by including the stand density variable, whereas for E. dunnii this variable was not statistically significant. This modelling framework provides an improvement in taper and tree volume predictions for E. dunnii and E. grandis in Uruguay. The possibilities offered by this methodology could be of interest for its application in countries where fast growing plantations are managed.

Keywords: Compatible Systems, Taper, Simultaneous Estimation, Intensive Silviculture, Eucalyptus

iForest 14 (2): 127-136 (2021) - doi: 10.3832/ifor3604-014
https://iforest.sisef.org/contents/?id=ifor3604-014

Research Articles: Modeling of time consumption for selective and situational precommercial thinning in mountain beech forest stands

Arnič D, Krč J, Diaci J — 2021-03-16

Arnič D, Krč J, Diaci J

MODELING OF TIME CONSUMPTION FOR SELECTIVE AND SITUATIONAL PRECOMMERCIAL THINNING IN MOUNTAIN BEECH FOREST STANDS

Abstract: Rationalization and optimization of work is becoming increasingly important in the European forestry sector. In this study a tool for modeling three different precommercial thinning approaches in young beech mountain stands was developed based on several field studies. The simulation examines three primary types of precommercial thinning: selective thinning and two types of situational thinning. We studied the impact of the number of candidates/crop trees and the impact of harvesting intensity on the structure and consumption of productive time. We found that in terms of costs situational precommercial thinning is more rational than selective precommercial thinning, that harvesting intensity has a significant impact on time consumption and that the number of candidates or crop trees has a significant impact on time consumption as well as on the relationships between main and auxiliary productive time. The modeling has shown that situational thinning is an alternative to selective thinning and that, in addition to requiring smaller and more efficient harvesting machines, it offers a cost-effective and ergonomic option (more walking, less chainsaw operation) for the pre-commercial thinning of young forest.

Keywords: Precommercial Thinning, Selective Thinning, Situational Thinning, Modeling, Crop Tree

iForest 14 (2): 137-143 (2021) - doi: 10.3832/ifor3556-014
https://iforest.sisef.org/contents/?id=ifor3556-014

Research Articles: Long-term effects of thinning and mixing on stand spatial structure: a case study of Chinese fir plantations

Li Y, Xu J, Wang H, Nong Y, Sun G, Yu S, Liao L, Ye S — 2021-03-08

Li Y, Xu J, Wang H, Nong Y, Sun G, Yu S, Liao L, Ye S

LONG-TERM EFFECTS OF THINNING AND MIXING ON STAND SPATIAL STRUCTURE: A CASE STUDY OF CHINESE FIR PLANTATIONS

Abstract: The regular planting and periodic harvesting of a single tree species are features of plantations, which are associated with a reduction of biodiversity. Such plantations are strongly encouraged to be converted into mixed forests. However, the spatial structure dynamics of plantations during the conversion process are poorly understood. In subtropical regions, thinned forest of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) and mixed forest of Chinese fir and Michelia macclurei Dandy are considered two ideal modes of plantation management. In this study, we analyzed the spatial structure dynamics of two forest stands and their six main tree populations over a rotation of 27 years, using spatial point analyses. We found that Chinese fir and M. macclurei had a regular distribution pattern (scale, r = 0-1 m) in the early stages of planting (1993), and Chinese fir maintained this pattern after experiencing self-thinning and selective cutting. In addition, non-planted tree species (i.e., natural regeneration of late-seral species, NRLSS) displayed significantly intraspecific clumping, which resulted in the distribution patterns of the forest stands changing from regular to aggregated (r = 0-5.5, 1-20 m), and the species distribution of mixed forest changed from random to clumped (r = 0-20 m). Moreover, during the management period (1993-2018), individuals were significantly differentiated in terms of size, and some small trees in the thinned forest were aggregated together. For the NRLSS, the diameter at breast height was randomly distributed (r = 0-20 m). Furthermore, Chinese fir and M. macclurei were separated at r = 0-1 m in the planting stage, but any pair of the six main populations in the thinned forest and mixed forest were randomly correlated over a rotation. Finally, the nearest neighbor distance of the stands became shorter after conversion, while the values for Chinese fir increased. After 25 years, the mixed plantation and the thinned plantation had a complex spatial structure. They develop towards natural forests and could be used as a template for future plantation management.

Keywords: Chinese Fir, Distribution Pattern, Mixed Forest, Plantation, Spatial Correlation, Thinning

iForest 14 (2): 113-121 (2021) - doi: 10.3832/ifor3489-014
https://iforest.sisef.org/contents/?id=ifor3489-014

Research Articles: Effects of low-impact logging on understory birds in the Brazilian Amazon

Soares JC, Amaral AO, De Moura RS, Cerboncini RA, Klemann Junior L — 2021-03-08

Soares JC, Amaral AO, De Moura RS, Cerboncini RA, Klemann Junior L

EFFECTS OF LOW-IMPACT LOGGING ON UNDERSTORY BIRDS IN THE BRAZILIAN AMAZON

Abstract: Tropical forests have a great potential for the exploitation of natural resources. Among the economic activities that depend on forest resources, timber production is the most important one. Nevertheless, these activities may negatively affect wildlife, the availability of natural resources, and ecosystem process. Here we analysed the effects of low-impact logging on understory bird species richness, number of individuals captured, species composition, and assemblage structure in central Brazilian Amazon. We compared logged and unlogged areas over a period of three years (from August 2014 to May 2017). We captured a total of 180 birds and 42 species (20 families) in the logged area and 226 birds and 49 species (20 families) in the unlogged area. Bird assemblage structure in the logged area changed more intensely over the three years of study and became more similar to the assemblage found in the unlogged area. The degree of similarity (Jaccard’s index) in species composition between logged and unlogged areas increased from 18% in the third year to 39% in the fifth year after logging. The results suggest that the minor effects of low-impact logging were reduced a few years after the disturbance, probably due to ecological succession. The proximity of logged and unlogged areas and the reduced impact in the study site may facilitate the recovery of the bird assemblage after the disturbance.

Keywords: Biodiversity, Conservation, Environmental Disturbance, Forest Resources, Sustainable Development

iForest 14 (2): 122-126 (2021) - doi: 10.3832/ifor3435-014
https://iforest.sisef.org/contents/?id=ifor3435-014

Research Articles: Tracing the acclimation of European beech (Fagus sylvatica L.) populations to climatic stress by analyzing the antioxidant system

Visi-Rajczi E, Hofmann T, Albert L, Mátyás C — 2021-03-01

Visi-Rajczi E, Hofmann T, Albert L, Mátyás C

TRACING THE ACCLIMATION OF EUROPEAN BEECH (FAGUS SYLVATICA L.) POPULATIONS TO CLIMATIC STRESS BY ANALYZING THE ANTIOXIDANT SYSTEM

Abstract: Through a common garden (provenance) experiment, we investigated the metabolic responses to climatic stress with regard to the acclimation potential of different European beech (Fagus sylvatica L.) populations. Selected enzymatic and non-enzymatic antioxidants were analyzed in leaves. Peroxidase (POD) and polyphenol oxidase (PPO) enzyme activity, total protein content as well as ABTS [2.2’-azino-bis-(3-etylbenzothiazoline)-6-sulphonic acid] antioxidant capacity were measured in the leaves of selected populations. Major leaf polyphenols were identified and their relative amounts were compared. Significant correlations were found between phenotypic (diameter growth) response to simulated climatic stress and the activity (and amount) of selected chemical components. The concentrations of certain polyphenols, POD enzyme activity, and total protein content may be chemical indicators of the acclimation potential of populations and may contribute to the forecasting of climate change effects, which can aid in the selection of suitable propagation material for adaptive silviculture.

Keywords: Beech, Drought Stress, Antioxidants, Phenotypic Plasticity, Provenance Trial, Climate Change

iForest 14 (2): 95-103 (2021) - doi: 10.3832/ifor3542-013
https://iforest.sisef.org/contents/?id=ifor3542-013

Review Papers: Climate change impacts on spatial distribution, tree-ring growth, and water use of stone pine (Pinus pinea L.) forests in the Mediterranean region and silvicultural practices to limit those impacts

Mechergui K, Saleh Altamimi A, Jaouadi W, Naghmouchi S — 2021-03-01

Mechergui K, Saleh Altamimi A, Jaouadi W, Naghmouchi S

CLIMATE CHANGE IMPACTS ON SPATIAL DISTRIBUTION, TREE-RING GROWTH, AND WATER USE OF STONE PINE (PINUS PINEA L.) FORESTS IN THE MEDITERRANEAN REGION AND SILVICULTURAL PRACTICES TO LIMIT THOSE IMPACTS

Abstract: Stone pine (Pinus pinea L.) has been cultivated since centuries in Mediterranean areas for its products and economic benefits, including edible pine nuts, timber, mushrooms, firewood, and grazing. However, current management objectives of stone pine stands also include recreational use, biodiversity conservation, protection from soil erosion, and CO2 fixation. Stone pine stands are considered to be among the ecosystems most vulnerable to climate change, and the current increase in drought frequency in the Mediterranean Basin has been shown to negatively impact their long-term establishment. Understanding the effects of climate change on the distribution, tree-ring growth and water use of stone pine forests can help assessing the adaptive capacity of the species, and developing management programs aimed at its conservation. This paper reviews the impacts of climate change on stone pine in the Mediterranean region. The high sensitivity of stone pine to climate change has been widely demonstrated in that: (i) climatic models predict the loss of suitable habitats and the shift of its geographical distribution in the next future; (ii) tree-ring analysis showed that winter and spring rainfalls have positive effects on growth, whereas high spring temperature has a negative effect; (iii) the strategy of stone pine to cope with water deficit affects the processes regulating its growth, including wood formation, leading to peculiar tree-ring anatomical features such as intra-annual density fluctuations. The silvicultural interventions and the most effective management strategies for stone pine forests are reviewed and discussed in the context of current climate change in the Mediterranean Basin.

Keywords: Stone Pine, Climate Change, Spatial Distribution, Tree-ring, Silvicultural Practices, Mediterranean Area

iForest 14 (2): 104-112 (2021) - doi: 10.3832/ifor3385-013
https://iforest.sisef.org/contents/?id=ifor3385-013

Research Articles: Carbon, nitrogen and phosphorus stoichiometry controls interspecific patterns of leaf litter-derived dissolved organic matter biodegradation in subtropical plantations of China

Wu PP, Ding YD, Li SL, Sun XX, Zhang Y, Mao R — 2021-02-19

Wu PP, Ding YD, Li SL, Sun XX, Zhang Y, Mao R

CARBON, NITROGEN AND PHOSPHORUS STOICHIOMETRY CONTROLS INTERSPECIFIC PATTERNS OF LEAF LITTER-DERIVED DISSOLVED ORGANIC MATTER BIODEGRADATION IN SUBTROPICAL PLANTATIONS OF CHINA

Abstract: Leaching of leaf litter is the primary source of dissolved organic matter (DOM) in forest soils. However, the interspecific variations of litter-derived DOM characteristics and biodegradation and their controlling factors remain unclear in subtropical plantations. Using fresh leaf litter of two broadleaf trees (Liquidambar formosana and Schima superba) and two coniferous trees (Pinus massoniana and P. elliottii) in subtropical plantations of China, we assessed the effects of tree species on the amounts and properties of litter-derived DOM with a short-term leaching experiment, and examined the interspecific variation of DOM biodegradation using a 56-day laboratory incubation method. Broadleaf tree litter generally leached higher amounts of dissolved organic carbon (DOC), dissolved total nitrogen (DTN), and dissolved total phosphorus (DTP) than coniferous tree litter. Compared with coniferous trees, broadleaf trees had higher DOM aromaticity and molecular weight, but lower DOC:DTP and DTN:DTP ratios in the litter leachates. Despite greater DOM aromaticity and molecular weight, broadleaf trees had higher litter-derived DOM biodegradation than coniferous trees because of the relatively lower DOC:DTP and DTN:DTP ratios. These results indicate the distinct patterns of litter-derived DOM characteristics and biodegradation between broadleaf and coniferous trees, and also highlight the predominant role of C:N:P stoichiometry in driving the interspecific variation of litter-derived DOM biodegradation in subtropical plantations of China.

Keywords: Broadleaf Trees, Coniferous Trees, DOM Aromaticity, DOM Molecular Weight, Leaching

iForest 14 (1): 80-85 (2021) - doi: 10.3832/ifor3609-013
https://iforest.sisef.org/contents/?id=ifor3609-013

Research Articles: Method for classifying sites to Atlantic Rainforest restoration aiming to increase basin’s streamflows

Cecílio RA, Oliveira-Ravani LT, Zanetti SS, Mendes HDA — 2021-02-19

Cecílio RA, Oliveira-Ravani LT, Zanetti SS, Mendes HDA

METHOD FOR CLASSIFYING SITES TO ATLANTIC RAINFOREST RESTORATION AIMING TO INCREASE BASIN’S STREAMFLOWS

Abstract: We propose a method to classify priority sites for Atlantic Rainforest restoration aiming to increase basin streamflows. The Rainfall Forest to Water Production (RFWP) method uses multicriteria analysis supported by GIS techniques and hydrological modeling. The method was applied to the Itapemirim River Basin, southeastern Brazil. The application of RFWP provided a map of areas with different priority for forest restoration by overlapping standardized numerical criteria with different weights (climatological, soil type/land use, and relief). The results indicated the influence of the wide distribution of the restoration sites on the streamflows. The RFWP proved to be suitable for the spatial analysis of the effect of different restoring areas on streamflows. Based on simulated scenarios, an increase in the native forest cover by restoration up to 27.6% of the basin area is expected to significantly enhance water production. The priority areas where forest restoration could better contribute to increase streamflows were delineated, especially at high altitude and in pastures, which are mostly in degraded conditions.

Keywords: GIS Application, Streamflow, Hydrologic Modeling, DHSVM

iForest 14 (1): 86-94 (2021) - doi: 10.3832/ifor3658-013
https://iforest.sisef.org/contents/?id=ifor3658-013

Research Articles: Response of soil bacterial communities to nitrogen and phosphorus additions in an age-sequence of subtropical forests

Dai Y, Wang H, Chen M, Wang D, Cao X, Chu B, Xu X — 2021-02-11

Dai Y, Wang H, Chen M, Wang D, Cao X, Chu B, Xu X

RESPONSE OF SOIL BACTERIAL COMMUNITIES TO NITROGEN AND PHOSPHORUS ADDITIONS IN AN AGE-SEQUENCE OF SUBTROPICAL FORESTS

Abstract: With global nitrogen (N) deposition continuously increasing, few reports exist describing how soil bacteria respond at the molecular level to long-term addition of excess N in variously aged forests. To reveal the responses of soil bacteria to the elevated N, an experiment was conducted with a chronic nutrient addition within differently aged stands (46-, 78-, and 200-years-old) in the northern subtropical China since 2011, including three treatments, CK (no N nor phosphorus (P) additions), N treatment (N, 100 kg N ha-1), and N with P (N+P, 100 kg N ha-1 + 50 kg P ha-1) to examine potential P limitation under N deposition. Metagenomic sequencing was used to examine the snapshot responses of soil bacterial communities. Soil moisture and texture, ammonium, nitrate, SOC (soil organic carbon), TN (soil total nitrogen), TP (total phosphorus), DOC (dissolved organic carbon), DON (dissolved organic nitrogen) were measured to explain the influence mechanism of forest age and fertilization on changes of microbial community. Following N addition, soil bacterial community diversity and most dominant phyla increased, but they showed a decrease with increasing stand age. The effects of fertilization on the same taxa were variable across forest ages. Soil bacterial community responded differently in 7-year fertilization, with distinct shift in 46-year-old forest and adaptability to long-term N addition in the 200-year-old forest. Soil texture and moisture, DOC, DON, pH, SOC/TN and TP were significantly correlated with bacterial community across stand ages, while N fertilization affected the bacterial community mostly via inducing soil moisture, NO3--N, DOC and pH in the 46-year-old forest, whose effects decreased with increasing stand age. Our results suggest that due to the variation of soil physicochemical properties among forest ages, soil bacterial communities are more stable and resilient to N deposition with increasing the age of stands. Soil bacterial communities might not encounter P limitation following the long-term addition of N in the subtropics.

Keywords: Nitrogen Deposition, Subtropical Evergreen Broadleaved Forest, Forest Age, Metagenomic, Soil Bacterial Community

iForest 14 (1): 71-79 (2021) - doi: 10.3832/ifor3655-013
https://iforest.sisef.org/contents/?id=ifor3655-013

Research Articles: Aboveground tree biomass of Araucaria araucana in southern Chile: measurements and multi-objective optimization of biomass models

2021-02-09

Kutchartt E, Gayoso J, Pirotti F, Bucarey A, Guerra J, Hernández J, Corvalán P, Drápela K, Olson M, Zwanzig M

ABOVEGROUND TREE BIOMASS OF ARAUCARIA ARAUCANA IN SOUTHERN CHILE: MEASUREMENTS AND MULTI-OBJECTIVE OPTIMIZATION OF BIOMASS MODELS

Abstract: Estimating carbon stocks in wooded systems is crucial to quantify national greenhouse gas balance estimates. However, inaccurate estimates are likely due to the divergent architecture of many species. The monkey puzzle tree Araucaria araucana, with its umbrella-like architecture is a vivid example. This species, often found in monodominant stands at high elevations, is the greatest carbon reservoir in the landscape, hence estimating its carbon storage is crucial. To provide the necessary basis for these estimations, we documented the variation in basic density and moisture content along the stem profile, identified the most suitable biomass estimation models, and quantified biomass allocation for three age ranges. We measured, felled, weighed, and separated trees into three categories: stem wood, stem bark, and foliage (branches + scaly leaves). The log-linear form of the simple allometric equation Y = aXb, based on diameter at breast height as the explanatory variable, covered a large part of the variation and showed good cross-validation performance (>0.96). Models using more covariates achieved lower absolute errors, but the estimation of the additional model parameters was associated with greater uncertainty. A multi-objective model comparison revealed that the best additional covariate to further improve biomass estimation was total tree height. The mean absolute percentage error was 9.8% for the total aboveground biomass, 8% for stem wood, 12% for stem bark and 24% for foliage. Changes in biomass distribution among tree components were related to age. For older trees, there was a relative increase in stem wood, a decreased proportion of foliage, but no change in stem bark. The proportion of stem bark biomass is similar to that of Araucaria angustifolia, but higher than in other conifers and most trees in general. Our results provide key properties for A. araucana and general guidance for the selection of easily-measurable variables allowing for excellent predictive power for local biomass estimation.

Keywords: Monkey Puzzle Tree, Carbon Stocks, Forest Modelling, Multicriteria Optimization, Allometry

iForest 14 (1): 61-70 (2021) - doi: 10.3832/ifor3492-013
https://iforest.sisef.org/contents/?id=ifor3492-013

Research Articles: Role of photosynthesis and stomatal conductance on the long-term rising of intrinsic water use efficiency in dominant trees in three old-growth forests in Bosnia-Herzegovina and Montenegro

2021-01-28

Palandrani C, Motta R, Cherubini P, Curović M, Dukić V, Tonon G, Ceccon C, Peressotti A, Alberti G

ROLE OF PHOTOSYNTHESIS AND STOMATAL CONDUCTANCE ON THE LONG-TERM RISING OF INTRINSIC WATER USE EFFICIENCY IN DOMINANT TREES IN THREE OLD-GROWTH FORESTS IN BOSNIA-HERZEGOVINA AND MONTENEGRO

Abstract: Old-growth forests have an important role in maintaining animal and plant diversity, are important carbon (C) reservoirs and are privileged sites to study long-term plant physiological responses, long-term forest dynamics and climate change impact on forest ecosystems. Several studies have highlighted how old-living trees undergo age-related declines with hydraulic limitations and reduction in photosynthesis, though some recent works have suggested that such a decline is not always observed. Our study aims at understanding the role of atmospheric CO2 increase on tree C uptake and stomatal conductance (gs) in old-living trees by analysing the long-term patterns of tree growth and intrinsic water use efficiency (iWUE) in three old-growth forests in the Balkans (Bosnia-Herzegovina and Montenegro), using dendrochronology and isotopic analysis. We hypothesised a long-term increase in iWUE in the studied old-growth forests, mostly related to enhanced photosynthesis rather than reduced stomatal conductance. Tree cores were sampled from dominant silver fir (Abies alba Mill.) trees in each forest. Tree-ring widths were measured and basal area increments (BAI) were assessed for each sampled tree and, from the six longest chronologies, five decades were chosen for cellulose extraction, its isotopic analysis (δ13C, δ18O), iWUE and leaf water 18O evaporative enrichment above the source water (Δ18OL) determination. We observed a continuous and significant increase in iWUE from 1800 to 2010 in the sampled dominant trees at all the three old-growth forests. Our BAI data and our estimates of Δ18OL across the study period support the idea that enhanced photosynthesis rather than reduced stomatal conductance is the major driver of the measured iWUE increase. Thus, our results support some recent findings challenging the hypothesis that iWUE in forests is primarily the result of a CO2-induced reduction in stomatal conductance as well as the so called hydraulic limitation hypothesis.

Keywords: Old-growth Forests, Intrinsic Water-Use Efficiency (iWUE), Basal Area Increment, Stable C Isotopes, Atmospheric CO2 Increase

iForest 14 (1): 53-60 (2021) - doi: 10.3832/ifor3414-013
https://iforest.sisef.org/contents/?id=ifor3414-013

Short Communications: Not all long-distance-exploration types of ectomycorrhizae are the same: differential accumulation of nitrogen and carbon in Scleroderma and Xerocomus in response to variations in soil fertility

Trocha LK, Bulaj B, Durska A, Frankowski M, Mucha J — 2021-01-18

Trocha LK, Bulaj B, Durska A, Frankowski M, Mucha J

NOT ALL LONG-DISTANCE-EXPLORATION TYPES OF ECTOMYCORRHIZAE ARE THE SAME: DIFFERENTIAL ACCUMULATION OF NITROGEN AND CARBON IN SCLERODERMA AND XEROCOMUS IN RESPONSE TO VARIATIONS IN SOIL FERTILITY

Abstract: Long-distance-exploration type (LDET) ectomycorrhizae have been reported to be best adapted to infertile soils, but variation within LDET ectomycorrhizae have not been thoroughly examined. Concentrations of nitrogen (N) and carbon (C) in LDET ectomycorrhizae were examined in Xerocomus-Pinus sylvestris and Scleroderma-Quercus petraea ectomycorrhizae. The study determined how concentrations of these elements vary in ectomycorrhizae in fertile (organic, uppermost mineral) and infertile (brunic) soil layers. The organic horizon in both Scots pine and sessile oak forest soils had the highest mineral status and exchange cations. In contrast, low mineral concentrations, high base saturation, and pH were characteristic of the brunic horizon in both forest stands. Xerocomus ectomycorrhizae had a higher concentration of N in the fertile (organic and uppermost mineral) soil horizons (3.4%) than in the infertile (brunic) soil horizon (2.2%). N concentration in Scleroderma ectomycorrhizae varied from 2.8%-3.0 % and did not differ between the studied soil horizons. The mean concentration of carbon in Xerocomus ectomycorrhizae varied from 29%-46% in Scots pine stands and from 41%-44% in Scleroderma ectomycorrhizae in sessile oak stands. The concentration of carbon in both Xerocomus and Scleroderma ectomycorrhizae was significantly higher in the fertile horizons (organic and uppermost mineral) compared to the brunic (infertile) horizon. In summary, the analysis conducted in the present study indicates that the LDET ectomycorrhizae, Xerocomus and Scleroderma, possess inherent variations in C and N content to manage soil resources.

Keywords: Ectomycorrhiza, Soil Interaction, Soil Nitrogen, Nitrogen Utilization, Ectomycorrhizal Adaptation, Soil Chemistry

iForest 14 (1): 48-52 (2021) - doi: 10.3832/ifor3594-013
https://iforest.sisef.org/contents/?id=ifor3594-013

Research Articles: Large-scale spatial distribution of deer browsing damage to young tree plantations

2021-01-14

Suzuki KK, Watanabe Y, Kubota T, Kuwano Y, Kawauchi Y, Yamagawa H, Yasuda M, Kondoh H, Nomiya H, Oka T

LARGE-SCALE SPATIAL DISTRIBUTION OF DEER BROWSING DAMAGE TO YOUNG TREE PLANTATIONS

Abstract: The economic loss caused by herbivore browsing in forest plantations is a concerning problem in many areas around the world. Information on the spatial distribution of browsing damage is important for forest owners when selecting locations for new plantations, because planting trees in areas of high browsing pressure increases economic losses. Although it is difficult to survey browsing damage across large areas, sporadic sampling data on browsing damage are often collected by foresters, governments, and researchers. Thus, in this study, we applied a generalized additive model (GAM) for analysis of sporadic data to reveal large-scale spatial variation in deer (Cervus nippon) browsing damage. A map of browsing pressure produced by a GAM that used years after planting (plantation age) and location as independent factors showed a few areas of high browsing pressure. In addition, browsing damage increased with increasing plantation age, and plantation stands aged 2+ years showed more browsing damage. Areas with high browsing damage estimated based on plantation stands aged 2+ years generally coincided with areas of high deer abundance, with some exceptions. Thus, this model reflects large-scale browsing damage relatively well and will help forest owners to avoid locating new plantations in areas of high browsing pressure.

Keywords: Cervus nippon, Deer Browsing Damage, Forest Management, Generalized Additive Model, Plantation

iForest 14 (1): 34-40 (2021) - doi: 10.3832/ifor3387-013
https://iforest.sisef.org/contents/?id=ifor3387-013

Research Articles: The economic value of fire damages in Tuscan agroforestry areas

Fagarazzi C, Fratini R, Montanino M, Viccaro M, Cozzi M, Romano S, Riccioli F — 2021-01-14

Fagarazzi C, Fratini R, Montanino M, Viccaro M, Cozzi M, Romano S, Riccioli F

THE ECONOMIC VALUE OF FIRE DAMAGES IN TUSCAN AGROFORESTRY AREAS

Abstract: The Tuscan Region (Central Italy) spends about 12 million euros every year in the prevention and suppression of forest fires. In this context, this study aims to analyse the economic and environmental benefits derived from fire suppression activities. Starting from a case study of a real fire event in Tuscany, we simulated three hypothetical scenarios (with different fire durations) without fire extinction activities planned by using the open source software FARSITE. Benefits derived from fire extinction activities can be quantified as the avoided damage, which has been calculated through the estimation of the total economic value of forests not destroyed by fire thanks to the extinction action. The avoided damage is represented by the difference between values of forest areas burned by the real fire event and those burned by simulated fire. By providing an economic estimation of avoided damages, our results confirm that forest fire services and forest management have a high impact on both the economy and the environment.

Keywords: Fire Damage, FARSITE, Total Economic Value, Fire Simulation, GIS

iForest 14 (1): 41-47 (2021) - doi: 10.3832/ifor3607-013
https://iforest.sisef.org/contents/?id=ifor3607-013

Research Articles: Dynamics of humus forms and soil characteristics along a forest altitudinal gradient in Hyrcanian forest

Bayranvand M, Akbarinia M, Salehi Jouzani G, Gharechahi J, Alberti G — 2021-01-10

Bayranvand M, Akbarinia M, Salehi Jouzani G, Gharechahi J, Alberti G

DYNAMICS OF HUMUS FORMS AND SOIL CHARACTERISTICS ALONG A FOREST ALTITUDINAL GRADIENT IN HYRCANIAN FOREST

Abstract: Humus forms are good indicators of environmental conditions and thus important in forest ecological processes. Altitudinal gradients are considered as natural laboratory for evaluating soil ecological processes and humus form distribution. The objective of this study was to evaluate the macromorphology of humus forms along an altitudinal gradient (0-2000 m a.s.l.) covered with plain forest, mixed and pure forests and forest-grassland ecotone, in Alborz Mountains in northern Iran. In total, 225 humus profiles were evaluated. Forest stand variables including tree density, basal area, crown density, and height, forest floor and soil physico-chemical properties along with biological features were measured. We found that altitudinal gradients influence both humus forms distribution and soil properties but with different mechanisms. While soil properties (i.e., temperature, pH, CaCO3, soil N content, soil C/N and microbial biomass N) were significantly correlated with altitude, the forest floor properties were more influenced by tree species composition. Particularly, the abundance of Mull was decreased in plain mixed forests compared to mountain pure forests, whereas the frequency of Amphi was increased. Moreover, Oligomull and Leptoamphi were abundant in mixed beech forests, while Eumacroamphi, Eumesoamphi and Pachyamphi were only observed in pure beech forests. Such a distribution influenced soil fertility where higher values of nitrogen (N), microbial biomass nitrogen (MBN) and pH were observed at lower altitudes under mixed forests compared to pure forests at higher altitudes.

Keywords: Altitude Gradient, Plant-humus-soil Relationships, Humus Systems, Soil Microbial Biomass

iForest 14 (1): 26-33 (2021) - doi: 10.3832/ifor3444-013
https://iforest.sisef.org/contents/?id=ifor3444-013

Research Articles: Estimation of total extractive content of wood from planted and native forests by near infrared spectroscopy

Teixeira Mancini L, Guedes Ramalho FM, Trugilho PF, Gherardi Hein PR — 2021-01-09

Teixeira Mancini L, Guedes Ramalho FM, Trugilho PF, Gherardi Hein PR

ESTIMATION OF TOTAL EXTRACTIVE CONTENT OF WOOD FROM PLANTED AND NATIVE FORESTS BY NEAR INFRARED SPECTROSCOPY

Abstract: The aim of this study was to evaluate the performance of multivariate models using Near infrared (NIR) spectra for predicting total extractives content of solid and powdered wood of planted and native species from tropical savanna. NIR spectra were recorded on the milled wood and radial surface of solid wood specimens of Cedrela sp., Jacaranda sp., Apuleia sp., Aspidosperma sp. and clones of Eucalyptus hybrids via an integrating sphere and fiber optics probe. NIR spectral signatures were evaluated by Principal Component Analysis (PCA) and then associated to the total extractive content quantified by extraction in toluene/ethanol (2:1) solutions, pure ethanol and hot water by Partial Least Squares (PLS) regressions. PCA revealed that NIR spectra measured in solid wood by integrating sphere gave a better discrimination of wood species. A global PLS model was developed based on NIR obtained by integrating sphere with satisfactory estimations both for solid wood (R²cv= 0.87, RMSECV= 1.08%) and wood powder (R²cv= 0.85, RMSECV= 1.19%). An independent test-set validation was performed with 25% of the samples and yielded R²p= 0.93 and RMSEP= 0.95% (for solid wood) and R²p= 0.87 and RMSEP= 1.40% (for wood powder). Both models can be applied for rapid screenings, though models developed from NIR spectra by integrating sphere on solid wood are considered more suitable for rapid predictions of extractive content in unknown wood specimens.

Keywords: Lumber, Multivariate Analysis, Non-destructive Testing, Test Set Validation, Wood Chemistry

iForest 14 (1): 18-25 (2021) - doi: 10.3832/ifor3472-013
https://iforest.sisef.org/contents/?id=ifor3472-013

Research Articles: Species interactions in pure and mixed-species stands of silver fir and European beech in Mediterranean mountains

2021-01-02

Versace S, Garfì V, Dalponte M, Febbraro Mirko D, Frizzera L, Gianelle D, Tognetti R

SPECIES INTERACTIONS IN PURE AND MIXED-SPECIES STANDS OF SILVER FIR AND EUROPEAN BEECH IN MEDITERRANEAN MOUNTAINS

Abstract: Interactions between tree species determine the dynamics of forest communities. Spatial and temporal changes in resource availability, variation in species composition and spatial distribution of trees may alter competitive interactions between species and, therefore, affect tree growth and forest productivity. In this study, we analyzed the intra and inter-specific interactions between European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.) in southern Italy (Molise and Calabria regions), and how these interactions affect basal area increments in mixed-species and pure stands. Results showed that intra-specific interactions have a negative effect on the basal area increment, both in pure and mixed-species stands of Molise and Calabria. Basal area increment was higher influenced by intra-specific interactions in pure stands than in mixed-species stands. Silver fir in Molise showed higher basal area increment in mixed-species stand, probably in relation with stand structure and space occupation that resulted in less competition between individual trees. European beech showed high values of intra-specific interactions in pure stands, likely related to the low self-tolerance of this species and to the spatial arrangement of trees, due to canopy closure. The absence of inter-specific interactions in mixed-species stands could be explained by the sub-dominant position of European beech, which may have limited the benefit derived from niche separation and complementarity for silver fir.

Keywords: Abies alba Mill., Fagus sylvatica L., Intra-specific Interactions, Inter-specific Interactions, Stand Productivity, Tree Growth

iForest 14 (1): 1-11 (2021) - doi: 10.3832/ifor3476-013
https://iforest.sisef.org/contents/?id=ifor3476-013

Research Articles: Interaction between planting spacing and wood properties of Eucalyptus clones grown in short rotation

2021-01-02

Soares Brito A, Baptista Vidaurre G, da Silva Oliveira JT, Missia Da Silva JG, Ferreira Oliveira R, Dias Júnior AF, Chaves Arantes MD, Cabral Moulin J, Valin M, De Siqueira L, Valverde Zauza EA

INTERACTION BETWEEN PLANTING SPACING AND WOOD PROPERTIES OF EUCALYPTUS CLONES GROWN IN SHORT ROTATION

Abstract: Wood quality results from the interaction between the genotype of trees and the silvicultural conditions to which they were subjected. Based on this interaction, research on the factors that add value to the woody raw material has an impact on the production of various forest products. This study aimed to evaluate the influence of different planting spacings (3×1, 3×2, 3×3 and 3×4 m) on the wood properties of three 4-year-old Eucalyptus clones. The wood of each clone was evaluated based on basic density, dry mass, anatomy, structural chemical composition, ash content and higher heating value. For at least one of the three clones studied, the planting spacing explained the variations in the basic density, dry mass, diameter and frequency of vessels and wall thickness of the wood fibers. Regardless of the eucalyptus clone, the area of vessels, the length and fraction of the fiber wall, as well as the contents of extractives, lignin, ash and the higher heating value of the wood were not influenced by the planting spacing. In summary, the change in the useful area alters the properties of wood in eucalyptus genetic materials in different ways and intensities at 4 years old.

Keywords: Wood Quality, Useful Area for Planting, Eucalyptus Genetic Materials, Harvesting Age

iForest 14 (1): 12-17 (2021) - doi: 10.3832/ifor3574-013
https://iforest.sisef.org/contents/?id=ifor3574-013

Research Articles: Influence of inorganic salts on biomass production, biochemical composition, and bioethanol production of Populus alba

Sim SJ, Yong SH, Park D, Choi E, Seol Y, Song HJ, Jeong MJ, Kim HG, Choi MS — 2020-12-07

Sim SJ, Yong SH, Park D, Choi E, Seol Y, Song HJ, Jeong MJ, Kim HG, Choi MS

INFLUENCE OF INORGANIC SALTS ON BIOMASS PRODUCTION, BIOCHEMICAL COMPOSITION, AND BIOETHANOL PRODUCTION OF POPULUS ALBA

Abstract: Inorganic salts are very important for the biosynthesis of major components such as cellulose and lignin. In order to investigate biomass production, major components of the biosynthesis of plant cell wall and the bioethanol production of Populus alba, we examined the effect of inorganic salts on in vitro culture systems without specific mineral salts. The medium without H2PO4- was supportive for Populus alba shoot growth, while the absence of NH4+ resulted in poor shoot growth. The medium without H2PO4- and Fe3+ inhibited above-ground biomass production, whereas NH4+ and K+ deprivation led to an enhancement of the same. The root/shoot ratio of Populus alba in the medium without H2PO4- was high compared with plants cultured in the control medium. H2PO4- is deeply involved in lignin biosynthesis, and its removal has been shown to reduce the biosynthesis of lignin. Plants grown on nitrate-free medium were found to be good for enzymatic saccharification and ethanol production. The plants grown in the medium without NO3- showed 72.0% enzyme digestibility, and the yield of ethanol showed 9.58% ethanol productivity after 12 hours. These results can be used as the basis for producing high-quality biomass for future bioethanol production.

Keywords: Enzymatic Hydrolysis, Fermentation, Inorganic Salts, In vitro Culture, Populus alba

iForest 13 (6): 566-574 (2020) - doi: 10.3832/ifor3438-013
https://iforest.sisef.org/contents/?id=ifor3438-013

Research Articles: Magnolia grandiflora L. shows better responses to drought than Magnolia × soulangeana in urban environment

2020-12-07

Vastag E, Orlović S, Konôpková A, Kurjak D, Cocozza C, Pšidová E, Lapin K, Kesić L, Stojnić S

MAGNOLIA GRANDIFLORA L. SHOWS BETTER RESPONSES TO DROUGHT THAN MAGNOLIA × SOULANGEANA IN URBAN ENVIRONMENT

Abstract: Drought tolerance is becoming an increasingly important criterion for the selection of tree species, especially in urban areas characterized by low water availability. Apart from drought tolerance, the introduction of non-native species should be considered for new planting programs under such conditions to enhance the resilience of urban forests. The present study is aimed at evaluating the in situ physiological responses of Magnolia grandiflora and Magnolia × soulangeana to severe drought that frequently occurs in urban environments in the Southeastern Europe. Transpiration rate, stomatal conductance, intercellular CO2 concentration, water-use efficiency and intrinsic water-use efficiency showed notable differences both between species and between the measured periods (wet and dry). Among the chlorophyll a fluorescence parameters, effective photochemical quantum yield of PS II, quantum yield of light-induced non-photochemical fluorescence quenching, quantum yield of non-regulated heat dissipation, fluorescence emission and index of susceptibility of leaves to light stress revealed significant differences both between the two species and the periods of measurements. The reduction of net photosynthesis in both magnolia species occurs as the result of non-stomatal limitation obtained by the reduction of electron transport rate coupled with simultaneous increase in intercellular CO2 concentration. Moreover, M. grandiflora was the species less vulnerable to water shortage conditions, while M. soulangeana exhibited a photosynthetic capacity sensitive to drought-induced stress. M. grandiflora can therefore be considered as a promising alternative to M. soulangeana for urban sites under the predicted climate change scenarios.

Keywords: Chlorophyll a Fluorescence, Drought, Leaf Gas Exchange, Photosynthesis, Urban Tree Selection

iForest 13 (6): 575-583 (2020) - doi: 10.3832/ifor3596-013
https://iforest.sisef.org/contents/?id=ifor3596-013

Research Articles: Controlling soil total nitrogen factors across shrublands in the Three Rivers Source Region of the Tibetan Plateau

Nie X, Wang D, Yang L, Zhou G — 2020-11-29

Nie X, Wang D, Yang L, Zhou G

CONTROLLING SOIL TOTAL NITROGEN FACTORS ACROSS SHRUBLANDS IN THE THREE RIVERS SOURCE REGION OF THE TIBETAN PLATEAU

Abstract: Alpine shrublands in the Three Rivers Source Region (TRSR) store substantial soil total nitrogen (N); however, limited information is available regarding its storage and controlling factors. To quantify the storage and controlling factors of soil total N stock, we analysed 66 soil profiles from samples obtained from 22 shrubland sites located across the TRSR on the Tibetan Plateau. Analytical methods, such as ordinary least squares regression, one-way analysis of variance, curve estimation, and variation partitioning were used to evaluate the effects of soil characteristics (soil organic carbon), vegetation characteristics (community types and ground cover of shrublands), climatic factors (mean annual temperature - MAT), and topographical features (slope) on soil N stock. Our results showed that soil N storage at a soil depth interval of 0-100 cm was 63.10 ± 27.41 Tg (Tg = 1012 g), with an average soil N stock of 2.44 ± 1.06 kg m-2 in the TRSR shrublands. Although the type of vegetation community had a small effect on soil N stock, the latter increased with increasing shrubland ground cover and soil organic carbon. However, soil N stock decreased with increasing topographical slope and MAT. Furthermore, changes in MAT primarily affected the N stock of topsoil. Among all the controlling factors, soil organic carbon explained most of the variation in the soil N stock. Considering the effects of global warming, an increase in MAT has decreased the soil N stock. Long-term monitoring of changes in soil N stock should be conducted to improve the precise estimation of soil N storage across the shrublands in the TRSR of the Tibetan Plateau.

Keywords: Soil N Storage, Ground Cover, SOC, MAT, Alpine Shrublands, Tibetan Plateau

iForest 13 (6): 559-565 (2020) - doi: 10.3832/ifor3533-013
https://iforest.sisef.org/contents/?id=ifor3533-013

Review Papers: Soil fungal communities across land use types

Balami S, Vašutová M, Godbold D, Kotas P, Cudlín P — 2020-11-23

Balami S, Vašutová M, Godbold D, Kotas P, Cudlín P

SOIL FUNGAL COMMUNITIES ACROSS LAND USE TYPES

Abstract: Land use change is one of the major causes of biodiversity loss, mostly due to habitat change and fragmentation. Belowground fungal diversity is very important in terrestrial ecosystems, however, the effect of land use change on soil fungal community is poorly understood. In this review, a total of 190 studies worldwide were analyzed. To monitor the effect of land use change, different fungal parameters such as richness, diversity, community composition, root colonization by arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi, spore density, ergosterol, and phospholipid fatty acid (PLFA) content and AM fungal glomalin related soil protein (GRSP) were studied. In general, results from analyzed studies often showed a negative response of fungal quantitative parameters after land use change from less-intensive site management to intensive site management. Land use change mostly showed significant shifts in fungal community composition. Considering land use change types, only 18 out of 91 land use change types were included in more than 10 studies, conversion of primary and secondary forest to various, more intensive land use was most often represented. All these 18 types of land use change influenced fungal community composition, however, the effects on quantitative parameters were mostly inconsistent. Current knowledge is not sufficient to conclude general land use impacts on soil fungi as the reviewed studies are fragmented and limited by the local context of land use change. Unification of the methodology, detailed descriptions of environmental factors, more reference sequences in public databases, and especially data on ecology and quantitative parameters of key fungal species would significantly improve the understanding of this issue.

Keywords: Soil Fungi, Land Use Change, Fungal Diversity, Species Composition, Mycorrhizal Fungi

iForest 13 (6): 548-558 (2020) - doi: 10.3832/ifor3231-013
https://iforest.sisef.org/contents/?id=ifor3231-013

Research Articles: The natural recovery of disturbed soil, plant cover and trees after clear-cutting in the boreal forests, Russia

Ilintsev A, Bogdanov A, Nakvasina E, Amosova I, Koptev S, Tretyakov S — 2020-11-18

Ilintsev A, Bogdanov A, Nakvasina E, Amosova I, Koptev S, Tretyakov S

THE NATURAL RECOVERY OF DISTURBED SOIL, PLANT COVER AND TREES AFTER CLEAR-CUTTING IN THE BOREAL FORESTS, RUSSIA

Abstract: This study aims to determine the impact of forest harvesting machinery on the temporarily moist soil of spruce forests (Picea abies Karst.) during the summer. For research purposes, we investigated 23 sites of the boreal forest in the European North of Russia (Arkhangelsk region) where logging operations had been carried out using harvesters and forwarders (CTL, cut-to-length harvesting). In the 15 years after logging, the sites were monitored for changes in physical soil properties and the depth/width of ruts and vegetation. In freshly cut areas, the depth of the ruts was linked to the amount of logging residue that had been used to strengthen skidding trails. After 15 years, the ruts were smooth but had not disappeared entirely. The average depth of the ruts decreased from 36 cm to 18 cm during the period under review. At a depth of 0-10 cm, the soil bulk density of the section between the control area and the wheel track increased by 19-27% within the first two years. At a depth of 10-20 cm, the soil bulk density only increased by 16-17% within the two-year period. After 15 years, the soil bulk density had decreased to the extent that there were no signs of heavy machinery movement. The natural restoration of vegetation in the ruts was affected by the presence of stagnant water in the initial post-logging period. Ruderal species and species with broad ecological amplitude to environmental factors grew over the skid trails. 15 years after logging, this overgrowth had stabilised, with the biodiversity level in the control area approaching its pre-logging state. Primarily, the renewal of the cutting areas occurred through species such as birch (Betula pendula Roth.) and aspen (Populus tremula L.). The highest amount of undergrowth (more than 30.000 ha-1) was detected 6-8 years after logging. This then decreases in areas that were cut down earlier. There are environmental consequences of clear-cutting (using the CTL system) on temporarily moist soil. To prevent the formation of deep ruts, it is recommended to leave 15-20 kg m-2 of felling residue.

Keywords: Clear-cuttings, Soil Disturbance, Rutting, Vascular Species, Natural Tree Regeneration

iForest 13 (6): 531-540 (2020) - doi: 10.3832/ifor3371-013
https://iforest.sisef.org/contents/?id=ifor3371-013

Research Articles: The analytic hierarchy process for selection of suitable trees for Mexico City

2020-11-18

Bravo-Bello JC, Martínez-Trinidad T, Romero-Sanchez ME, Valdez-Lazalde JR, Benavides-Meza H

THE ANALYTIC HIERARCHY PROCESS FOR SELECTION OF SUITABLE TREES FOR MEXICO CITY

Abstract: Urban foresters require methodologies that help to select tree species for urban environments, mainly in places where there is a large number of potential species such as the Valley of Mexico. We applied the Analytic Hierarchy Process (AHP) to select suitable native tree species that are under-represented or non-existent in Mexico City trees. Through bibliographic research, the selection criteria and the list of trees to be evaluated were selected; later, a group of specialists in urban forestry and arboriculture determined by pair-wise comparison matrices the specific weight of each selection criterion, while a set of taxonomists evaluated the rating of each attribute for each species. Finally, for practical purposes, the synthesis of both evaluations resulted in a ranking of 15 tree species according to their degree of aptitude suggested for Mexico City. According to results, Buddleja cordata, Quercus glaucoides and Litsea glaucescens obtained the highest degree of suitability as a large, medium and small-size species, respectively. The AHP proved to be an appropriate methodology to solve a complex problem through multiple criteria evaluation by diverse specialists in the subject. The implementation of the results contributes to the selection process of suitable tree species for urban environments.

Keywords: Multi-criteria Analysis, Native Species, Urban Environment, Urban Tree Diversity, Valley of Mexico

iForest 13 (6): 541-547 (2020) - doi: 10.3832/ifor3481-013
https://iforest.sisef.org/contents/?id=ifor3481-013

Research Articles: Harmonized dataset of surface fuels under Alpine, temperate and Mediterranean conditions in Italy. A synthesis supporting fire management

2020-11-13

Ascoli D, Vacchiano G, Scarpa C, Arca B, Barbati A, Battipaglia G, Elia M, Esposito A, Garfì V, Lovreglio R, Mairota P, Marchetti M, Marchi E, Meytre S, Ottaviano M, Pellizzaro G, Rizzolo R, Sallustio L, Salis M, Sirca C, Valese E, Ventura A, Bacciu V

HARMONIZED DATASET OF SURFACE FUELS UNDER ALPINE, TEMPERATE AND MEDITERRANEAN CONDITIONS IN ITALY. A SYNTHESIS SUPPORTING FIRE MANAGEMENT

Abstract: Surface biomass characterization plays a key role in wildfire management. It allows classifying vegetation fuels flammability for fire risk analysis, to define silvicultural prescriptions for fire hazard reduction, to plan prescribed burning, or to model fire behavior and its effects, such as greenhouse gas and pollutant emissions. To facilitate fuel classification and analysis of potential fire behavior and effects in Italy, we harmonized 634 measurements of surface wildland fuels from Alpine, temperate and Mediterranean environments. The dataset provides quantitative data for duff, fine dead fuels and downed woody material, live grasses and shrubs fuel components. Surface fuel data were harmonized by subdividing loads (Mg ha-1) to standard size classes for dead (0-6, 6-25 and 25-75 mm) and live (0-6, 6-25 mm) fuels, collecting percent cover and depth/height (cm) of the various fuel components, and classifying observations into 19 fuelbed categories. To ensure comparability with existing vegetation classification systems, we classified each observation according to the European Fuel Map, the Corine Land Cover classes (level IV), the European Forest Types, and the forest categories of the Italian National Forest Inventory. The dataset and a photo description of each fuelbed category are available as Supplementary material. This dataset is the first step to develop several products at the national scale such as: (i) fuel type classification and mapping; (ii) carbon stock and wildfire emission estimates; (iii) calibration of fuel models for the simulation of fire behavior and effects.

Keywords: Wildfire, Fire Behavior, Simulation, Fuel Types, Emissions

iForest 13 (6): 513-522 (2020) - doi: 10.3832/ifor3587-013
https://iforest.sisef.org/contents/?id=ifor3587-013

Research Articles: Effect of environmental gradients on leaf morphological traits in the Fandoghlo forest region (NW Iran)

Jahdi R, Arabi M, Bussotti F — 2020-11-13

Jahdi R, Arabi M, Bussotti F

EFFECT OF ENVIRONMENTAL GRADIENTS ON LEAF MORPHOLOGICAL TRAITS IN THE FANDOGHLO FOREST REGION (NW IRAN)

Abstract: The purpose of this study was to analyze the effects of altitude, the position of the trees along a gradient of canopy cover, and the orientation of their crown on leaf traits of 18 deciduous woody species belonging to 10 families in the Fandoglo forest region in Ardabil, North West of Iran. We measured eight leaf traits (leaf width, length, area, thickness, water content, leaf mass per area, specific leaf area, and dry matter concentration) of trees sampled at sites subjected to different light regimes (forest edge, forest understory, and isolated trees). All traits were measured on more than 3600 leaves from 90 trees sampled in two altitudinal ranges (low: 1300-1500 m a.s.l.; high: 1500-1700 m a.s.l.). A two-way ANOVA and t-test for independent samples were applied to test for differences in leaf traits between different altitudes and degree of canopy cover. The results confirmed that species’ leaf traits were more strongly correlated with the altitude and canopy cover rather than the orientation of the crown. No relationship between leaf traits and crown orientation was detected. All leaf traits had significantly higher values at low than at high elevation, indicating that environmental factors such as atmospheric CO2 concentration, temperature, light, irradiance, and wind deeply impact on foliar morphology and function; however, water content and specific leaf area showed an opposite trend. Also, species with different positions along the gradient of canopy cover could have different responses to elevation. Our results indicate that the variation of functional (morphological and physiological) traits in different tree species are affected by altitude and light regime. This might provide a theoretical basis for afforestation and forest management activities in the Fandoghlo forest region.

Keywords: Leaf Morphological Traits, Fandoglo Forest Region, Altitude, Tree Position, Crown Orientation

iForest 13 (6): 523-530 (2020) - doi: 10.3832/ifor3391-013
https://iforest.sisef.org/contents/?id=ifor3391-013

Research Articles: Phytopathogenic fungi in forest nurseries of Middle Siberia

Sheller MA, Shilkina EA, Ibe AA, Razdorozhnaya TY, Sukhikh TV — 2020-11-05

Sheller MA, Shilkina EA, Ibe AA, Razdorozhnaya TY, Sukhikh TV

PHYTOPATHOGENIC FUNGI IN FOREST NURSERIES OF MIDDLE SIBERIA

Abstract: The paper presents the results of phytopathogenic fungi determination in bare-root forest nurseries of Middle Siberia. Genetic analysis of pathogenic microflora of Pinus sylvestris L., Pinus sibirica Du Tour and Picea obovata Ledeb. seedlings allowed identification of 17 genera of micromycetes: Phoma Sacc., Lophodermium Chevall., Sclerophoma Höhn. (teleomorph Sydowia Bres.), Cladosporium Link, Alternaria Nees, Typhula (Pers.) Fr. etc. Most frequently detected fungi represented genera Phoma (23.7 %) and Lophodermium (23.6 %). Pinus sylvestris L. seedlings harboured the highest diversity of fungal taxa. Seven genera of microscopic fungi (Phoma sp., Didymella sp., Alternaria sp., Cladosporium sp., Lophodermium sp., Gremmenia sp., Sclerophoma sp.) were detected in all studied forest zones: taiga, forest-steppe and Southern-Siberian mountain. The obtained results demonstrate the usefulness of DNA analysis for the identification of phytopathogenic fungi in forest nurseries of Middle Siberia with several implications for increasing the efficacy of forest management.

Keywords: Forestry, Forest Nurseries, Phytopathogens, Conifers, DNA analysis, ITS Region, Phytopathological Monitoring

iForest 13 (6): 507-512 (2020) - doi: 10.3832/ifor3507-013
https://iforest.sisef.org/contents/?id=ifor3507-013

Research Articles: Soil water deficit as a tool to measure water stress and inform silvicultural management in the Cape Forest Regions, South Africa

Scheepers GP, Du Toit B — 2020-11-01

Scheepers GP, Du Toit B

SOIL WATER DEFICIT AS A TOOL TO MEASURE WATER STRESS AND INFORM SILVICULTURAL MANAGEMENT IN THE CAPE FOREST REGIONS, SOUTH AFRICA

Abstract: An understanding of variations in water availability to plantation forests on a spatial and temporal scale is essential when designing risk averse and site-specific silvicultural management regimes. Various indices of site water availability were compared to each other and to an independent, unbiased estimate of stand productivity potential, namely site index, across the Tsitsikamma, Knysna and Boland forestry regions of South Africa. This was done to find the balance between water availability indices requiring intensive data inputs (that may be very accurate) and indices with lower input data requirements (but may sacrifice some accuracy). The following indices of water availability (in order from low to higher input data requirements) were tested: Mean Annual Precipitation (MAP); Aridity Index (AI), i.e., MAP as a fraction of mean annual potential evapotranspiration (Ep); Moisture Growing Season (MGS), i.e., the Julian days where long-term MAP exceeds 0.3 times Ep; Water Deficit (WD), an estimate based on a rudimentary water balance with relatively low data inputs. The first three estimates use only climatic variables while the WD incorporates soil water storage capacity to run a water balance calculation. Results showed that both regional climatic variability and soil properties significantly affected the level of water availability, and hence also the potential productivity of pine stands. The shallow and sandy soils from the Knysna and Boland regions exhibited rapid water depletion during periods of decreased precipitation and seasonal shifts, however, the large WD’s (up to 345 mm year-1) observed in several of these sites rapidly changed to surplus values following only one month of high precipitation. Sites from the Tsitsikamma region had significantly larger water retention capabilities and this was attributed to the regional soil properties and climatic conditions. Temporal variations in the WD were also quantified. The WD estimates correlated significantly (r = -0.80, p<0.001) to the respective site indices from sites across all regions. These results underscore the importance of soil water availability on plantation productivity, especially in moderately dry regions or in areas with either shallow soils or a seasonal rainfall pattern. We conclude that the WD is a fairly accurate estimate of site-specific water availability with relatively low data requirements. The WD estimates are far superior to currently used indices of water availability in Southern Africa and has data input requirements that are currently readily available for most plantation forest sites.

Keywords: Soil Water Availability, Climatic Gradient, Slash Pine, Monterey Pine, Edaphic Properties

iForest 13 (6): 473-481 (2020) - doi: 10.3832/ifor3059-013
https://iforest.sisef.org/contents/?id=ifor3059-013

Research Articles: Analysing species abundance distribution patterns across sampling scales in three natural forests in Northeastern China

Tan L, Zhang P, Zhao X, Fan C, Zhang C, Yan Y, Von Gadow K — 2020-11-01

Tan L, Zhang P, Zhao X, Fan C, Zhang C, Yan Y, Von Gadow K

ANALYSING SPECIES ABUNDANCE DISTRIBUTION PATTERNS ACROSS SAMPLING SCALES IN THREE NATURAL FORESTS IN NORTHEASTERN CHINA

Abstract: Understanding how and why species abundance distributions (SADs) vary with sampling scale has been a long-standing issue in ecology. By fitting various SAD models with observations collected in three large forest field plots, the objective of this study is to explore how the shape of SADs and the predictive ability of SAD models vary with sampling scales. Based on a large dataset collected in the Changbaishan, Jiaohe and Liangshui forests in northeastern China, observed SADs were compared with SADs estimated using five different models (log-normal, broken stick, Zipf, niche preemption and neutral model) at four sampling scales (10 × 10 m, 30 × 30 m, 60 × 60 m and 90 × 90 m). The results show that the studied SADs are scale dependent. Niche-based models provided a better fit at small sample sizes, the predictive ability decreasing with increasing sampling scale. The neutral model performed better at large sample sizes, the predictive ability increasing with increasing sampling scale. We identify the models that provided the best fit to observed species abundance distributions across spatial scales, and conclude that there is not one best SAD model for all spatial scales. Future studies should consider the scale effects on the species abundance distribution.

Keywords: Community Ecology, Neutral Theory, Niche Theory, Scale Effects, Species Abundance Distribution, Temperate Forest, Woody Plants

iForest 13 (6): 482-489 (2020) - doi: 10.3832/ifor3211-013
https://iforest.sisef.org/contents/?id=ifor3211-013

Research Articles: Biochar amendment regulated growth, physiological, and biochemical responses of conifer in red soil

Tarin Muhammad Waqqas K, Fan L, Cai Y, Tayyab M, Chen L, He T, Rong J, Zheng Y — 2020-11-01

Tarin Muhammad Waqqas K, Fan L, Cai Y, Tayyab M, Chen L, He T, Rong J, Zheng Y

BIOCHAR AMENDMENT REGULATED GROWTH, PHYSIOLOGICAL, AND BIOCHEMICAL RESPONSES OF CONIFER IN RED SOIL

Abstract: The addition of Biochar (BC) into the soil is expected to improve soil physicochemical properties and plant growth. However, few studies have verified such an effect on the growth and physiological characteristics of conifers. The current study aims to assess the efficacy of novel physiological parameters as an indicator for assessing the impact of hardwood biochar (BH) on the development of Fokienia hodginsii seedlings to strengthen our understanding of the impacts of the BH on soil to optimize the achievement of BC-based restoration projects. The BH was applied to the soil under four different levels (0, 5, 20, and 80 g Kg-1 of soil) to assess their influence on the leave’s photosynthetic pigments, photosynthesis (Pn), and biochemical traits of F. hodginsii seedlings in four different seasons, and on biomass and soil physicochemical properties at final harvest under greenhouse conditions for one year. In the first two seasons, BH20 and BH80 amended seedlings responded with an improved photosynthetic rate with more production of photosynthetic pigments and biochemical attributes. However, none of the BC doses increased the Pn of seedlings in the final season. Nonetheless, after one year a rise in soil pH as well as P and K availability resulted in a maximum 25% increase in biomass of F. hodginsii under BH80 amendments. Our findings reveal that the incorporation of BH (20 and 80 g kg-1 of soil) has a substantial positive effect on seedling biomass and soil fertility. However, the application of BH into acidic soils may be effective in restoring degraded soils if initially combined with fertilizers. We recommend a careful approach to the selection of BC because its influence may vary between different soil types, plant species, and BC feedstocks.

Keywords: Fokienia hodginsii, Hardwood Biochar, Restoration, Photosynthesis

iForest 13 (6): 490-498 (2020) - doi: 10.3832/ifor3416-013
https://iforest.sisef.org/contents/?id=ifor3416-013

Research Articles: Estimating the distribution characters of Larix kaempferi in response to climate change

Wu C, Shen J, Chen D, Du C, Sun X, Zhang S — 2020-11-01

Wu C, Shen J, Chen D, Du C, Sun X, Zhang S

ESTIMATING THE DISTRIBUTION CHARACTERS OF LARIX KAEMPFERI IN RESPONSE TO CLIMATE CHANGE

Abstract: A better understanding of the distribution of suitable habitats of Larix kaempferi and its environmental constraints is crucial to know how global climate change will affect its growth and future dynamics. We simulated global suitable distribution areas of L. kaempferi under current and future climates, using different representative concentration pathway (RCP) scenarios, to evaluate the main factors affecting its geographical distribution. The results showed that under current climate conditions the suitable distribution areas of L. kaempferi are concentrated in Europe and Asia, followed by North America. The “Germany-Sweden-Britain” (19.42% of the total worldwide area) and “China-Japan-North Korea” (43.11%) regions are the cores for L. kaempferi distribution. The suitable distribution area for L. kaempferi is large in China (33.75% of the total area). The suitable distribution areas in Asia, Europe, and China decreased and shifted northward in the RCP scenarios. The main climatic factors affecting the distribution of L. kaempferi were the annual mean temperature, mean temperature of the coldest quarter, annual mean precipitation, and precipitation in the driest month. L. kaempferi could adapt or move to higher latitudes/altitudes to cope with climate change. Our results contribute to the introduction, cultivation, and management of L. kaempferi and potentially of other deciduous gymnosperms.

Keywords: Suitable Distribution Areas, Maxent Model, Environmental Variable, RCPs, Cultivation and Management

iForest 13 (6): 499-506 (2020) - doi: 10.3832/ifor3570-013
https://iforest.sisef.org/contents/?id=ifor3570-013

Research Articles: Shifts in the arbuscular mycorrhizal fungal community composition of Betula alnoides along young, middle-aged plantation and adjacent natural forest

Jing Y, Li T, Cui H, Li L, Allen SC, Chen L, Li Y, Zhao Z — 2020-10-07

Jing Y, Li T, Cui H, Li L, Allen SC, Chen L, Li Y, Zhao Z

SHIFTS IN THE ARBUSCULAR MYCORRHIZAL FUNGAL COMMUNITY COMPOSITION OF BETULA ALNOIDES ALONG YOUNG, MIDDLE-AGED PLANTATION AND ADJACENT NATURAL FOREST

Abstract: Betula alnoides is a fast-growing and native timber species prevalently planted in tropical and subtropical areas of southern China. Despite the large-scale development of B. alnoides plantations, knowledge of its association with arbuscular mycorrhizal fungi (AMF) is limited. In the present study, we chose young (3-year-old sapling, P3y) and middle-aged (12-year-old stand, P12y) B. alnoides plantations and adjacent native forest (N) in the Puwen Tropical Forest Experimental Station located in Xishuangbanna prefecture of Yunnan Province, southwestern China, as study materials and explored the change in AMF community composition in the plantation chronosequence. In addition, we combined morphological methods and Illumina MiSeq sequencing techniques to analyze rhizosphere soil AMF. The results indicated that the AMF richness and diversity indexes of B. alnoides at two ages tended to be similar to those of natural growing trees in native forest. However, the specific AM fungal compositions were distinctly different, providing evidence of the conservation value of the native forest, which harbors a unique AMF diversity. Hierarchical cluster analysis further revealed that the AMF community composition of trees in the mid-aged stand (P12y) was more similar to that of naturally growing B. alnoides (N) than that of the young-aged trees (P3y), which proved the considerable resilience of AMF to the establishment of the B. alnoides plantation. A set of at least five soil properties (available phosphorus, available nitrogen, organic matter, total nitrogen and silt content) was found to play a significant role in shaping the AMF communities. These results contribute to the understanding of the impacts of B. alnoides plantations on AMF diversity and composition. Such information is critical for the efficient planting and sustainable management of B. alnoides plantations.

Keywords: Arbuscular Mycorrhizal Fungi, Betula alnoides, Plantation, Native Forest

iForest 13 (5): 447-455 (2020) - doi: 10.3832/ifor3515-013
https://iforest.sisef.org/contents/?id=ifor3515-013

Research Articles: Diversity of saproxylic beetle communities in chestnut agroforestry systems

2020-10-07

Parisi F, Lombardi F, Marziliano PA, Russo D, De Cristofaro A, Marchetti M, Tognetti R

DIVERSITY OF SAPROXYLIC BEETLE COMMUNITIES IN CHESTNUT AGROFORESTRY SYSTEMS

Abstract: Chestnut (Castanea sativa Mill.) has been exploited over the centuries for different uses. Nowadays, chestnut is mostly managed as coppice or orchard, creating a matrix of different forest structures. In particular, saproxylic species may provide information to correlate forest naturalness with stand structure. In this study, we evaluated how different management methods might influence the diversity of beetles hosted in chestnut agroforestry systems. Three management options were considered: young and mature coppice stands, and the traditional fruit orchard. Microhabitats occurring on veteran trees were also surveyed to investigate their effect on saproxylic communities, in the fruit orchard. The study area is located in Southern Italy, Aspromonte National Park, where Coleoptera were collected using window flight traps and the stand structural traits were also quantified. In the fruit orchard, a census of the occurring microhabitats was also realized. We used the following diversity indeces (α-diversity) to assess the state of conservation of the analysed forests: (i) Shannon Index; (ii) Margalef’s Richness index; (iii) Equitability index; (iv) Dominance index. Results revealed that forest management have a fundamental role in influencing the diversity of Coleoptera communities and saproxylic beetles. A lower species richness was observed in the mature coppice in comparison with the young coppice and fruit orchard. Nevertheless, these agroforestry systems, reflecting differentiated structural traits, allowed the development of highly specialized and threatened species (34.3% included in IUCN risk categories), with important contribution to conservation of biodiversity in the rural landscape. Finally, the abundance and diversity of microhabitats in the traditional fruit orchard had positive effects on many saproxylic beetle families. These beetle communities, particularly saproxylic species, can be used as excellent bioindicators in actively managed agroforestry systems, suggesting sustainable forest management options for chestnut, while the conservation of veteran trees rich in microhabitats can be considered fundamental for preserving many endangered insects.

Keywords: Apennines, α-diversity, Biodiversity Indicators, Chestnut Orchards, Coppice Stands, Forest Management, Threatened Species

iForest 13 (5): 456-465 (2020) - doi: 10.3832/ifor3478-013
https://iforest.sisef.org/contents/?id=ifor3478-013

Research Articles: Investigations on yellowing of chestnut crowns in Trentino (Alps, Northern Italy)

Bertoldi D, Miorelli P, Pedrazzoli F, Delugan S, Deromedi M, Maresi G — 2020-10-07

Bertoldi D, Miorelli P, Pedrazzoli F, Delugan S, Deromedi M, Maresi G

INVESTIGATIONS ON YELLOWING OF CHESTNUT CROWNS IN TRENTINO (ALPS, NORTHERN ITALY)

Abstract: Yellowing of part or the whole canopy of chestnut trees was observed during the summer of 2014 in the areas of Tenno, Pranzo and Drena in Trentino, where chestnut cultivation is traditional on the lateral moraine deposit in a context of a prevalent limestone lithological substrate. Symptoms were observed on chestnut trees of different ages, either grafted or not, scattered or in stripes along the maximum slope. Investigations were carried out in the form of field surveys, chemical and molecular analyses of soil and leaves and greenhouse trials, to assess the damage evolution and its causes. No known pathogens emerged during the field surveys, and laboratory tests excluded the presence of phytoplasma infections. A comparison of yellow and asymptomatic leaves evidenced significant deficiencies of manganese (Mn) and iron (Fe) in the yellow leaves, though the level of the two nutrients was the same in the soil below green and yellowed trees. Experimental run-off trials in the greenhouse reproduced the foliage damage with a continuous basic water regime; open-field fertilizations with Mn and Fe led to a slightly recovery on the part of some treated leaves, thus confirming the hypothesis of a probable, sudden deficiency of the mentioned microelements. A possible explanation of this phenomenon could be, on one side, the high precipitation level of 2014, and, on the other side, the previous outbreaks of the Asian chestnut gall wasp, that had reduced foliage volume and thus the organic substance in the soil. The natural recovery from symptoms was clearly visible in trees after four years in a context of normal rainfall regime and increasing organic acid in the soil, after effective biological control of wasp. Even if related to a particular and rare geological condition, this is the first description of Mn deficiency in Castanea sativa.

Keywords: Chestnut Yellowing, Castanea sativa, Phytoplasmas, Foliar Deficiencies, Manganese

iForest 13 (5): 466-472 (2020) - doi: 10.3832/ifor3488-013
https://iforest.sisef.org/contents/?id=ifor3488-013

Short Communications: The effects of salicylic acid, oxalic acid and chitosan on damping-off control and growth in Scots pine in a forest nursery

Soltys A, Studnicki M, Zawadzki G, Aleksandrowicz-Trzcinska M — 2020-09-24

Soltys A, Studnicki M, Zawadzki G, Aleksandrowicz-Trzcinska M

THE EFFECTS OF SALICYLIC ACID, OXALIC ACID AND CHITOSAN ON DAMPING-OFF CONTROL AND GROWTH IN SCOTS PINE IN A FOREST NURSERY

Abstract: Modern forestry in the European Union and in Poland is in constant search of environment-friendly technological solutions. These also relate to nursery production, in which attempts are made to apply non-chemical plant-protection products. The objective of this study was to assess the effects of salicylic acid, oxalic acid and chitosan (applied in the form of Beta-chikol®) in controlling damping-off and promoting the growth of Scots pine seedlings under nursery conditions. All the substances were used in seed treatment and in the form of foliar spray, 4 times during the growing season, in the following concentrations: salicylic acid 1% and 2%, oxalic acid 0.5% and 1%, and chitosan 2%. Seedlings were inventoried three times: 3 and 6 weeks after seed sowing, and at the end of the growing season. All seedlings were counted in 1-metre segments of individual rows of the seedbed. At the end of the growing season, parameters of seedling growth like shoot length, root-collar diameter, root length and the dry mass of above-ground parts were determined. The growth of pine seedlings was found to be stimulated by both chitosan and oxalic acid, while salicylic acid proved inhibitory to growth when present at 2% concentration, and showed no detectable influence on biometric parameters at 1% concentration. Numbers of seedlings germinating per 1-metre segment were significantly greater than in the (unprotected) control, where chitosan was applied. Likewise, oxalic acid applied at both concentrations was associated with greater numbers of germinating pine seedlings than in the control, albeit the statistical significance of this difference was achieved only 6 weeks after seed sowing, and only with the 0.5% concentration. Numbers of seedlings per metre-long segment were significantly lower in response to both concentrations of salicylic acid applied. Both chitosan (applied as Beta-chikol®) and 0.5% oxalic acid resulted in seedling protection against damping-off and enhanced growth, whereas the applied concentrations of salicylic acid were presumably excessive, hence the negative impact on both germination and growth.

Keywords: Plant Biostimulants, Induced Resistance, Pinus sylvestris, Growth Stimulation, Disease Control

iForest 13 (5): 441-446 (2020) - doi: 10.3832/ifor3244-013
https://iforest.sisef.org/contents/?id=ifor3244-013

Technical Reports: Remote sensing of american maple in alluvial forests: a case study in an island complex of the Loire valley (France)

Martin H, Monnet JM, De Boisvilliers M, Chevalier R, Villar M — 2020-09-16

Martin H, Monnet JM, De Boisvilliers M, Chevalier R, Villar M

REMOTE SENSING OF AMERICAN MAPLE IN ALLUVIAL FORESTS: A CASE STUDY IN AN ISLAND COMPLEX OF THE LOIRE VALLEY (FRANCE)

Abstract: Due to their particular topographic position between land and river, riparian forests are ecosystems rich in biodiversity. In France, along the Middle Loire (from Nevers to Angers), Black poplar (Populus nigra L.) forests are often in mixtures with the American maple (Acer negundo L.), introduced into the country in the 18th century. We tested the detectability of American maple by LiDAR and very high-resolution multispectral imagery on an island complex. We found that coupling the point cloud height standard deviation with a vegetation index in the red, green and blue spectrums discriminated American maple with a success rate of more than 90%.

Keywords: Acer negundo, American Maple, Box Elder, Populus nigra, Black Poplar, Airborne Laser Scanning, Remote Sensing, Exogenous Woody Species, Loire River

iForest 13 (5): 409-416 (2020) - doi: 10.3832/ifor3237-013
https://iforest.sisef.org/contents/?id=ifor3237-013

Research Articles: Tree volume modeling for forest types in the Atlantic Forest: generic and specific models

2020-09-16

Cysneiros VC, Gaui TD, Silveira Filho TB, Pelissari AL, Machado SDA, De Carvalho DC, Moura TA, Amorim HB

TREE VOLUME MODELING FOR FOREST TYPES IN THE ATLANTIC FOREST: GENERIC AND SPECIFIC MODELS

Abstract: National Forest Inventories are important primary data sources for large-scale forest resource surveys, in which volume estimates of sampled trees are essential for quantitative analysis. Volume prediction models in natural forests are scarce in Brazil due to legal restrictions for cutting trees, especially in the Atlantic Forest. This study aimed to fit volume models for the main forest types and timber species of the Atlantic Forest in Rio de Janeiro state, considering two hypotheses: (I) generic volume models provide greater generalizability of estimates; however, (II) they may reduce the accuracy of forest type- and species-specific predictions. Four linear models with logarithmic transformation of variables were evaluated to fit volume models for generic and specific datasets, which correspond to the main forest types and timber species. Goodness-of-fit statistics were calculated to compare the accuracy and efficiency of the models, and selected models were validated through leave-one-out cross-validation procedures. The estimates obtained by generic and specific models were compared by non-parametric hypothesis tests. Generic models showed similar predictions to the specific models for forest types and timber species, with similar potential for stem and total volume predictions. Therefore, generic models can be used for Atlantic Forests in Rio de Janeiro state, while specific models are recommended to obtain more detailed local estimates.

Keywords: Allometric Models, National Forest Inventory, Non-destructive Methods, Goodness-of-fit, Stem and Total Volume

iForest 13 (5): 417-425 (2020) - doi: 10.3832/ifor3495-013
https://iforest.sisef.org/contents/?id=ifor3495-013

Research Articles: Spatial modeling of the ecological niche of Pinus greggii Engelm. (Pinaceae): a species conservation proposal in Mexico under climatic change scenarios

2020-09-16

Martínez-Sifuentes AR, Villanueva-Díaz J, Manzanilla-Quiñones U, Becerra-López JL, Hernández-Herrera JA, Estrada-Ávalos J, Velázquez-Pérez AH

SPATIAL MODELING OF THE ECOLOGICAL NICHE OF PINUS GREGGII ENGELM. (PINACEAE): A SPECIES CONSERVATION PROPOSAL IN MEXICO UNDER CLIMATIC CHANGE SCENARIOS

Abstract: Pinus greggii is a species of socio-economic importance in terms of wood production and environmental services in Mexico, though it is restricted by particular environmental conditions to the Sierra Madre Occidental. Species distribution models are geospatial tools widely used in the identification and delineation of species’ distribution areas and zones susceptible to climate change. The objectives of this study were to: (i) model and quantify the environmentally suitable area for Pinus greggii in Mexico, and possible future distributions under four different scenarios of climate change; (ii) identify the most relevant environmental variables that will possibly drive changes in future distribution; and (iii) to propose adequate zones for the species’ conservation in Mexico. Some 438 records of Pinus greggii from several national and international databases were obtained, and duplicates were discarded to avoid overestimations in the models. Climatic, edaphic, and topographic variables were used and 100 distribution models for current and future scenarios were generated using the Maxent software. The best model had an area under the curve (AUC) of 0.88 and 0.93 for model training and validation, respectively, a partial ROC of 1.94, and a significant Z test (p<0.01). The current estimated suitable area of Pinus greggii in Mexico was 617,706.04 ha. The most relevant environmental variables for current distribution were annual mean temperature, mean temperature of coldest quarter, and slope. For the 2041-2060 models, annual mean temperature, precipitation of coldest quarter, and slope were the most important drivers. The use of climatic models allowed to predict a future decrease in suitable habitat for the species by 2041-2060, ranging from 48,403.85 (7.8% - HadGEM2-ES RCP 8.5 model) to 134,680.17 ha (21.8% - CNRM-CM5 RCP 4.5). Spatial modeling of current and future ecological niche of Pinus greggii also allowed to delineate two zones for in situ conservation and restoration purpose in northeastern (Nuevo Leon) and central (Hidalgo) Mexico.

Keywords: Conservation, Climate Change, MaxEnt, Sierra Madre Oriental, Pinus greggii

iForest 13 (5): 426-434 (2020) - doi: 10.3832/ifor3491-013
https://iforest.sisef.org/contents/?id=ifor3491-013

Research Articles: Wildfire and harvesting effects on carbon dynamics in an oak-pine mixed forest

Kaptanoglu AS, Namli A — 2020-09-16

Kaptanoglu AS, Namli A

WILDFIRE AND HARVESTING EFFECTS ON CARBON DYNAMICS IN AN OAK-PINE MIXED FOREST

Abstract: CO2 emission to the atmosphere is the main cause of global warming. The impacts of land-use changes for agriculture and urbanisation, deforestation, and fire disturbance are attributed to the increase in CO2 emissions. Soil respiration, largely due to microbial activity, is one of the CO2 sources being released to the atmosphere. In this regard, several soil parameters related with carbon cycle, including organic matter, total N, C/N ratio, CO2 efflux, microbial biomass C (Cmic), the Cmic/Corg ratio, the metabolic quotient qCO2, and β-D glucosidase activity, were determined in a burned (harvested, H; non-harvested, NH), and its adjacent unburned (UB), mixed oak-pine forest to estimate the effects of burning and removal of residual woods. The Cmic increased gradually with burning and harvesting after Month 9, and sharp increases were observed in all areas, likely due to the abundant rainfall after Month 12. CO2 efflux decreased in the burned areas at Months 4 and 6; however, this reversed in Month 9. In spite of non-significant differences, we detected higher CO2 efflux values in the unburned areas compared to the burned ones, probably as a result of the drought effect observed in the burned areas up to Months 9 and 12 due to the increased soil heat. There was no significant difference between the H and NH burned areas, while both areas were different from the unburned areas in all soil parameters, except CO2 efflux and qCO2. The harvesting effect was not significant compared to the fire effect with regard to the considered soil variables, likely due to the management and protection of the burned area which allowed a fast vegetation recover. The abundance of the microbial biomass was independent of the changes in CO2 efflux and showed a negative correlation with β-D glucosidase activity. This might be related to the variation in substrate quality, microbial composition and abundance after burning and harvesting.

Keywords: CO2 Evolution, β-D Glucosidase Activity, qCO2, Soil Microbial Biomass Carbon, Wildfire

iForest 13 (5): 435-440 (2020) - doi: 10.3832/ifor3312-013
https://iforest.sisef.org/contents/?id=ifor3312-013

Research Articles: Effects of stand age on litter quality, decomposition rate and nutrient release of Kazdagi fir (Abies nordmanniana subsp. equi-trojani)

Savaci G, Sariyildiz T — 2020-09-03

Savaci G, Sariyildiz T

EFFECTS OF STAND AGE ON LITTER QUALITY, DECOMPOSITION RATE AND NUTRIENT RELEASE OF KAZDAGI FIR (ABIES NORDMANNIANA SUBSP. EQUI-TROJANI)

Abstract: The influence of stand age on litter quality, decomposition rate and nutrient release was examined in pure stands of Kazdagi fir (Abies nordmanniana subsp. equi-trojani [Steven] Spach) differing in age (Fir38, Fir60, Fir90 and Fir100 years). The needle litters were collected and analysed for initial total carbon, cellulose, hemicellulose, lignin and nutrient concentrations (N, P, K, Ca, S, Mg, Mn and Fe). Initial litter quality parameters varied significantly among the four stand age classes. The Fir60 and Fir100 stands had higher total C than the Fir38 and Fir90 stands, while the Fir38 and Fir100 stands had higher N than the Fir60 and Fir90 stands. Mean cellulose and hemicellulose concentrations were highest in the Fir90 stand, while mean lignin concentration was highest in the Fir38 stand. Fir90 stand showed the highest ratios of C/N and Lignin/N. In general, the older fir stands showed higher Ca, Mg and K concentrations and lower P and S concentrations than the younger stands. The litter, however, showed higher a Mn concentration under the Fir60. Mean Fe concentration was highest under the Fir38 stand and lowest under the Fir60 stand. Litter decomposition was studied in the field using the litterbag technique. The litterbags were placed on the soil under each stand age class and sampled every 6 months for 2 years. The interaction of stand age and time on the mass loss was significant (p<0.01). The repeated measures ANOVA showed that the main effect of time on the mass loss was also significant (p<0.001). Needle litters under Fir100 and Fir60 stands decomposed faster than the needle litters under Fir90 and Fir38 stands. The calculated times required for 50% mass loss were higher under Fir38 (1.35 y) and Fir90 (1.27 y) stands than under Fir100 (1.05 y) and Fir60 (1.06 y) stands. The litters in Fir38 and Fir90 stands need approximately 4 years for 95% mass loss compared to the litters in Fir60 and Fir100 stands, which need 3 years. In general, Ca, Mg and S concentrations increased over time, whereas K and Mn decreased. These results illustrate that stand age is a key factor to be considered when studying litter decomposition dynamics.

Keywords: Litter Quality, Stand Age, Litter Decomposition, Nutrient Release, Fir

iForest 13 (5): 396-403 (2020) - doi: 10.3832/ifor3306-013
https://iforest.sisef.org/contents/?id=ifor3306-013

Short Communications: When a definition makes the difference: operative issues about tree height measures from RPAS-derived CHMs

De Petris S, Berretti R, Sarvia F, Borgogno Mondino E — 2020-09-03

De Petris S, Berretti R, Sarvia F, Borgogno Mondino E

WHEN A DEFINITION MAKES THE DIFFERENCE: OPERATIVE ISSUES ABOUT TREE HEIGHT MEASURES FROM RPAS-DERIVED CHMS

Abstract: Tree height (H) survey is a fundamental step in forest mensuration. The error affecting tree height measure, necessarily influences the correspondent tree estimates. The remotely survey of vegetation using PHODAR (PHOtogrammetric Detection And Ranging) or LiDAR (Light Detection And Ranging) techniques generates very high-density point clouds, that result into Canopy Height Models (CHMs) having GSD (Ground Sampling Distance) of few centimetres. This GSD value potentially allows to survey single crown apexes, which, from a forestry point of view, do not represent the actual tree height. Apex height value, in fact, does not represent the prevailing dendrometric height (PDH) but the maximum tree value. In this study we propose a new approach aimed at measuring dendrometric height by PHODAR derived CHM, taking care about this issue. The proposed method defines a correcting factor (found equal to 95% percentile of CHM values distribution within a given crown) for the tree height extraction from CHM based on the PDH concept. The method could be implemented to single crown approach in forest parameters extraction algorithms permitting more reliable results, especially in terms of tree volume and related estimations (e.g., carbon stock quantification, allometric models).

Keywords: Tree Height, Prevailing Dendrometric Height, CHM, PHODAR, LiDAR

iForest 13 (5): 404-408 (2020) - doi: 10.3832/ifor3411-013
https://iforest.sisef.org/contents/?id=ifor3411-013

Research Articles: Estimation of fuel loads and carbon stocks of forest floor in endemic Dalmatian black pine forests

Bakšić N, Bakšić D — 2020-09-01

Bakšić N, Bakšić D

ESTIMATION OF FUEL LOADS AND CARBON STOCKS OF FOREST FLOOR IN ENDEMIC DALMATIAN BLACK PINE FORESTS

Abstract: Estimation of forest floor loading is important for many forest management applications, especially those related to fire management and carbon balance. We quantified the physical properties (depth, fuel load, bulk density) and carbon stocks of endemic Dalmatian black pine (Pinus nigra J.F. Arnold subsp. dalmatica [Vis.] Franco) forest floor layers. We also examined how these properties differ with stand age and layer. Forest floor depths ranged from 1.5 cm to 11.5 cm and forest floor fuel (FFF) loads ranged from 11.9 Mg ha-1 in the young stand to 197.3 Mg ha-1 in the old stand. Forest floor carbon (FFC) stocks ranged from 6.4 Mg C ha-1 in the young stand to 85.8 Mg C ha-1 in the old stand. We developed regression equations that can be used to convert the investigated forest floor depth into load in each layer individually and across all layers. These equations, together with the organic carbon (OC) concentration determined here for individual forest floor layers, simplify quantification of carbon stocks in the forest floor. Bulk density (BD) values reported here can also be used to convert depth measurements to loads for each layer and the entire forest floor. The results presented here are suitable for rapid estimation of FFF loads and FFC stocks based solely on forest floor depth, without the need to sample and analyze large amounts of forest floor fuels. Similarly, spatial distribution in FFF loads and carbon stocks can be assessed simply by measuring forest floor depths.

Keywords: Dalmatian Black Pine, Forest Floor, Fuel Load, Carbon Stock, Bulk Density

iForest 13 (5): 382-388 (2020) - doi: 10.3832/ifor3184-013
https://iforest.sisef.org/contents/?id=ifor3184-013

Research Articles: Development phases and structural characteristics of the Penteleu-Viforta virgin forest in the Curvature Carpathians

Chivulescu S, Ciceu A, Leca S, Apostol B, Popescu O, Badea O — 2020-09-01

Chivulescu S, Ciceu A, Leca S, Apostol B, Popescu O, Badea O

DEVELOPMENT PHASES AND STRUCTURAL CHARACTERISTICS OF THE PENTELEU-VIFORTA VIRGIN FOREST IN THE CURVATURE CARPATHIANS

Abstract: The stand structure of a virgin forest situated at an average altitude of 1130 m a.s.l. in the Milea Viforta Nature Reserve (Southern Carpathians, Romania) was investigated to determine the specific development phases of the forest and understand how they influence the stand structure, with the aim of providing optimal solutions and structural models for sustainable forest management. All trees with breast height diameter (dbh) ≥ 8 cm were inventoried in the study plot (1 ha), and the main dendrometrical variables were measured. Radial increment cores were taken from all the trees and were subsequently processed. A total of 317 trees from three species - European beech (Fagus sylvatica), silver fir (Abies alba) and Norway spruce (Picea abies) - were sampled at different development phases (optimum, ageing, breakdown and dieback, rejuvenation). Testing stand structural diversity with the Gini index, a minimal stability was found in the rejuvenation development phase and a maximum stability in the ageing phase. No significant match was found between standard theoretical functions (Normal, Weibull, Gamma and Exponential) and the observed distribution of tree diameter. Also, it was confirmed that dominance of beech in all development phases is a consequence of its high competitive ability and its capacity to endure difficult environmental and biologically stressful conditions. The results revealed a series of structural models specific to these forest ecosystems, which can help managing forests under the selection system.

Keywords: Primary Forest, Development Phases, Uneven Aged Forests, Carpathians Forest

iForest 13 (5): 389-395 (2020) - doi: 10.3832/ifor3094-013
https://iforest.sisef.org/contents/?id=ifor3094-013

Research Articles: The effect of provenance of historical timber on tree-ring based temperature reconstructions in the Western Central Alps

Riechelmann DF, Hartl C, Esper J — 2020-08-25

Riechelmann DF, Hartl C, Esper J

THE EFFECT OF PROVENANCE OF HISTORICAL TIMBER ON TREE-RING BASED TEMPERATURE RECONSTRUCTIONS IN THE WESTERN CENTRAL ALPS

Abstract: Millennial-length tree-ring width chronologies are used to reconstruct temperature and place recent warming into historical context. The Simplon valley in the Western Central Alps is an ideal region for such a study as it provides historical timber back to medieval times which can be combined with temperature sensitive living larch trees. However, the exact provenance of the historical timber is unknown, but might origin from different elevations which potentially biases derived temperature reconstructions. To study the effect of elevation on tree growth and climate sensitivity, approximately 250 trees at three elevational levels (1500, 1700, and 2000 m a.s.l.) were sampled. Results indicate that the overall growth rate decreases with increasing elevation. Significant correlations between tree-ring width and summer temperature are recorded at tree sites ≥ 1700 m a.s.l. The comparison of the growth patterns between living trees and historical timber from Simplon Village (1476 m a.s.l.) reveals a most likely origin of the historical samples between 1700 and 2000 m a.s.l. When combining the data from the living trees at the different elevational levels with the historical timber, to produce three separate chronologies spanning the past 1200 years, substantial low frequency differences are recorded after RCS detrending the data. This finding demonstrates that the origin of samples in combined (living + historical) chronologies has a strong influence on long-term summer temperature reconstructions. It is thus important to analyse the growth characteristics of historical timber, and estimate their provenance in comparison to living trees, when producing millennial length chronologies.

Keywords: Elevational Transect, European Larch, Climate Response, Summer Temperature, Dendrochronology

iForest 13 (5): 351-359 (2020) - doi: 10.3832/ifor3412-013
https://iforest.sisef.org/contents/?id=ifor3412-013

Review Papers: Towards better practices of salvage logging for reducing the ecosystem impacts in Mediterranean burned forests

Pons P, Rost J, Tobella C, Puig-Gironès R, Bas JM, Franch M, Mauri E — 2020-08-25

Pons P, Rost J, Tobella C, Puig-Gironès R, Bas JM, Franch M, Mauri E

TOWARDS BETTER PRACTICES OF SALVAGE LOGGING FOR REDUCING THE ECOSYSTEM IMPACTS IN MEDITERRANEAN BURNED FORESTS

Abstract: An average of 213,000 ha of European forest is affected by fire every year, with 90% of this area corresponding to Mediterranean countries. The timber of the burned forests is usually harvested by clearcutting over large areas to be used mainly as bioenergy. Recent scientific evidence has shown the strong impact that these “salvage logging” practices have on the ecosystem. However, forest owners and companies largely ignore academic debate, and salvage logging decisions are usually taken for economic, practical and emotional reasons. We propose a process to connect scientists and practitioners with the aim of providing evidence-based guidelines to protect biodiversity and ecosystem services, which can be used as a general model. The process involves five steps: (1) to review the available scientific knowledge on post-fire forest management; (2) to synthesize the information to produce a handbook of best practices in Mediterranean burned forests; (3) to provide a tool to help decision-making in post-fire management; (4) to actively disseminate this knowledge to the forest sector; and (5) to fill knowledge gaps with new experimental studies aimed to assess the environmental impact of some of the most feasible management alternatives. The feedback of the forest sector has been obtained along the process, and recommendations for better practices are already being promoted among forest owners by the administration. We suggest that similar processes can be conducted in other socio-environmental contexts to improve the management of disturbed forests and to generalize our knowledge on the topic.

Keywords: Biodiversity, Ecosystem Services, Evidence-based Management, Salvage Logging, Sustainable Logging, Wildfires

iForest 13 (5): 360-368 (2020) - doi: 10.3832/ifor3380-013
https://iforest.sisef.org/contents/?id=ifor3380-013

Research Articles: Efficacy of Phlebiopsis gigantea against Heterobasidion conidiospore and basidiospore infection in spruce wood

2020-08-25

Bruna L, Klavina D, Zaluma A, Kenigsvalde K, Burneviča N, Nikolajeva V, Gaitnieks T, Piri T

EFFICACY OF PHLEBIOPSIS GIGANTEA AGAINST HETEROBASIDION CONIDIOSPORE AND BASIDIOSPORE INFECTION IN SPRUCE WOOD

Abstract: Treatment of freshly cut stumps with biological control agents containing Phlebiopsis gigantea spores effectively restricts the spread of new Heterobasidion infections in conifer forests. To test the control efficacy of different P. gigantea strains, conifer stumps or billets cut from tree stems can be artificially infected with asexual Heterobasidion conidiospores or sexual basidiospores or left for natural basidiospore infection. Currently, no information is available about whether the control efficiency of P. gigantea in Norway spruce wood is affected by Heterobasidion spore type. In the present study, the impact of four P. gigantea strains (including the commercial product Rotstop®) on initiation and development of Heterobasidion basidiospore and conidiospore infections as well as the relationship between the area occupied by P. gigantea and control efficacy were analysed in spruce billets. The mean size of the area occupied by P. gigantea was larger, and the efficacy of P. gigantea against Heterobasidion was significantly higher in billets left for natural basidiospore infection compared to treatment with Heterobasidion conidiospore suspension. The control efficacy against Heterobasidion infection was high, although only a small area of the billet surface was occupied by P. gigantea and even when there was no visible discoloration caused by P. gigantea infection on wood surfaces.

Keywords: Picea abies, Billets, Conidiospores, Basidiospores

iForest 13 (5): 369-375 (2020) - doi: 10.3832/ifor3279-013
https://iforest.sisef.org/contents/?id=ifor3279-013

Technical Reports: Assessment of allergenic potential in urban forests: a case study of the Royal Park of Portici in Southern Italy

Rispo M, De Masi L, Calandrelli MM — 2020-08-25

Rispo M, De Masi L, Calandrelli MM

ASSESSMENT OF ALLERGENIC POTENTIAL IN URBAN FORESTS: A CASE STUDY OF THE ROYAL PARK OF PORTICI IN SOUTHERN ITALY

Abstract: In modern cities, the abundance of allergenic plant species has contributed to making less healthy the urban environment, as on-going and direct contact of humans with the urban flora can increase the negative effects on people allergic to pollens. The allergenicity of ornamental species should be considered, and above all quantified, when designing new urban green areas. Numerous studies reported the detailed description of the flora present in cities, but only in some rare cases their allergenic power and related pollen seasons were mentioned. In the present study, starting from the existing data in literature on the vascular flora of the Royal Park of Portici, Southern Italy, tree and shrub species have been classified based on their ability to cause respiratory allergies. Thus, to estimate the allergenic potential of urban green space, two preliminary approaches were defined based on the biological characteristics of the plant species as sources of pollen emissions.

Keywords: Pollens, Allergies, Vascular Flora, Urban Green Parks, Urban Planning

iForest 13 (5): 376-381 (2020) - doi: 10.3832/ifor3485-013
https://iforest.sisef.org/contents/?id=ifor3485-013

Research Articles: Vascular plants diversity in short rotation coppices: a reliable source of ecosystem services or farmland dead loss?

Fehér A, Končeková L, Halmová D, Prus P, Izakovičová Z, Dragoi M — 2020-08-17

Fehér A, Končeková L, Halmová D, Prus P, Izakovičová Z, Dragoi M

VASCULAR PLANTS DIVERSITY IN SHORT ROTATION COPPICES: A RELIABLE SOURCE OF ECOSYSTEM SERVICES OR FARMLAND DEAD LOSS?

Abstract: Short rotation coppices (SRCs) are a relatively new type of crop stand that is usually established on agricultural land in intensively used landscapes. However, SRCs also offer services other than the production of renewable energy. We evaluated the more complex significance of SRCs by including the other important potential ecosystem services of these stands. The objective of this paper was to evaluate the ecosystem services and disservices of SRCs by inductive (bottom-up) methods moving from the species-level to the ecosystem services on the basis of the spontaneous vascular plants diversity in SRCs. We also compared the plant-diversity-based potential ecosystem services and disservices of field SRCs, crops and forests in the same landscape in southwestern Slovakia. It was found that SRCs had an intermediate vascular plants species composition between those of forest ecosystems and agroecosystems. Among the ten evaluated ecosystem services and disservices, considering the sum of the positive and negative evaluations, SRCs had an intermediate position between the forests and arable-land vegetation. When comparing the ecosystem services of the SRCs with those of the forest ecosystems and agroecosystems, the SRCs achieved the best rating for species richness, remediation and collectables. SRCs had the worst rating for providing pasture and had the highest proportion of toxic and allergenic plants. Interestingly, SRCs achieved positive values in ecosystem services and mainly recorded the worst values in the ecosystem disservices. The direct utilization of these services and the economic balance of ecosystem services and disservices require further study.

Keywords: Bioenergy, Ecosystem Service, Farmland, Forest Ecosystem, Short Rotation Coppice

iForest 13 (4): 345-350 (2020) - doi: 10.3832/ifor3055-013
https://iforest.sisef.org/contents/?id=ifor3055-013

Research Articles: Estimation of forest cover change using Sentinel-2 multi-spectral imagery in Georgia (the Caucasus)

Mikeladze G, Gavashelishvili A, Akobia I, Metreveli V — 2020-08-07

Mikeladze G, Gavashelishvili A, Akobia I, Metreveli V

ESTIMATION OF FOREST COVER CHANGE USING SENTINEL-2 MULTI-SPECTRAL IMAGERY IN GEORGIA (THE CAUCASUS)

Abstract: Our objective was to use Sentinel-2A multispectral data in order to cost-effectively detect change in forest cover in Georgia (the Caucasus). Generalized additive models (GAMs) were used to fit forest cover measures to Sentinel-2A spectral band values modified using different topographic correction methods. Canopy closure (calculated from upward-looking fisheye photographs taken beneath forest canopy) was the best forest cover measure accounted for by the Sentinel-2 spectral data that were topographically corrected using the Minnaert Correction (R2 = 0.882). Spectral bands best explaining canopy closure were Band 3 (Green), Band 8 (NIR) and Band 12 (SWIR). Our model is able to reasonably detect spatial and temporal changes in canopy closure, even in highly rugged terrain and diverse vegetation cover, and it has potential to be improved to the extent that it can be applied by managers of natural resources. Based on free open source applications in combination with cheap gadgets our approach might play an important role in monitoring the forests of countries with low economic indicators.

Keywords: Generalized Additive Models, Forest Cover, Satellite Imagery, Sentinel-2, Fisheye, Topographic Correction

iForest 13 (4): 329-335 (2020) - doi: 10.3832/ifor3386-013
https://iforest.sisef.org/contents/?id=ifor3386-013

Research Articles: The cork oak in the Mountains of Palermo (Italy): ecological insights from the south-eastern edge of its distribution range

2020-08-07

Badalamenti E, Scalenghe R, La Mantia T, Bueno RS, Sala G, Pizzurro GM, Giaimo A, Pasta S

THE CORK OAK IN THE MOUNTAINS OF PALERMO (ITALY): ECOLOGICAL INSIGHTS FROM THE SOUTH-EASTERN EDGE OF ITS DISTRIBUTION RANGE

Abstract: The uneven presence of the cork oak (Quercus suber L.) within its distribution range is not only determined by its climatic requirements but also by specific edaphic needs. Although most of the natural populations thrive in acidic soils deriving from metamorphic or volcanic rock outcrops, some cork oak populations are found growing in soils deriving from calcareous bedrock, which are considered less suitable. We carried out a multidisciplinary investigation at the south eastern edge of the Q. suber distribution range (Mountains of Palermo, NW Sicily), including soil, floristic, and vegetation surveys, aimed at: (i) assessing the native or introduced origin of some peculiar cork oak populations; (ii) describing the associated plant communities and soils; (iii) identifying the ecological factors which could explain the local adaptation to soils deriving from calcareous bedrock; (iv) discussing the ecological role played by this species in the study area and within its distribution range. The collected information suggest that the detected cork oak stands are native to these areas. We hypothesized that the co-occurrence of high fire frequency, high soil calcium content and erosion, which caused the intermixing of different parent materials, might favor its competitive interactions with other Mediterranean tree species, thus accounting for the local presence of Q. suber. The study of cork oak populations thriving in peculiar substrates at the driest end of the range could be of great importance for the future conservation of this species, which is expected to face growing threats in the coming decades.

Keywords: Mediterranean Evergreen Forest, Soil Chemistry, Vegetation Science, Wildfire, Landscape, Tree Species, Quercus suber

iForest 13 (4): 336-344 (2020) - doi: 10.3832/ifor3360-013
https://iforest.sisef.org/contents/?id=ifor3360-013

Short Communications: An assessment of the availability of cavities for secondary cavity-nesting birds in certified and conventionally-logged Neotropical rainforests

Schaaf AA, Tallei E, Ruggera RA, Vivanco CG, Rivera L, Politi N — 2020-07-28

Schaaf AA, Tallei E, Ruggera RA, Vivanco CG, Rivera L, Politi N

AN ASSESSMENT OF THE AVAILABILITY OF CAVITIES FOR SECONDARY CAVITY-NESTING BIRDS IN CERTIFIED AND CONVENTIONALLY-LOGGED NEOTROPICAL RAINFORESTS

Abstract: The high level of forest intervention and the decrease in biodiversity as a result of logging are incentives to implement forest certification schemes. Despite the advances in the results of the impact of forest certification on biodiversity, there are few studies on species with specific habits, such as cavity-nesting birds. The objective of this study is to compare the impact of forest certification and conventional logging on the richness, availability (density) and dominance of potentially suitable cavity trees for secondary cavity-nesting birds in the subtropical forests of northwestern Argentina. Seven sites were selected: three control sites which were not logged for at least 40 years, one site under Forest Stewardship Council (FSC) certification, and three sites with conventional logging. The results suggest that logged forests under FSC-certification may guarantee a diversity, availability (density) and dominance of potentially suitable cavity trees for secondary cavity-nesting birds, as well as certain characteristics (such as DBH > 40 cm), similar to unlogged forests for this group of birds. Therefore, we suggest that the forests of northwestern Argentina should be managed by a scheme under forest certification so that the high levels of cavity tree species are maintained.

Keywords: Argentina, Birds, Cavity Trees, Certification Forest, Forest Stewardship Council, South-America, Subtropical Forests

iForest 13 (4): 318-322 (2020) - doi: 10.3832/ifor3220-013
https://iforest.sisef.org/contents/?id=ifor3220-013

Research Articles: Public perceptions of forests across Italy: an exploratory national survey

Carrus G, Panno A, Aragones JI, Marchetti M, Motta R, Tonon G, Sanesi G — 2020-07-28

Carrus G, Panno A, Aragones JI, Marchetti M, Motta R, Tonon G, Sanesi G

PUBLIC PERCEPTIONS OF FORESTS ACROSS ITALY: AN EXPLORATORY NATIONAL SURVEY

Abstract: In a context of progressive expansion of the Italian forest area, we present the results of a national survey exploring public perception of forests across different geographical scales in Italy. Perceptions of forests are assessed in relation to popular beliefs on relevant environmental issues such as countering climate change, protecting biodiversity, and promoting social cohesion and environmental education. Participants (N = 1059) living in five different regions of Northern (Trentino-Alto Adige/Südtirol, Piemonte), Central (Lazio, Molise) and Southern Italy (Puglia), were recruited in the survey and completed a paper-and-pencil questionnaire. Survey questions regarded the estimated percentage of forest cover, the perceived importance of different environmental issues and of different material and non-material forest products, as well as participants’ perceptions regarding connectedness to nature. Results revealed a generalized tendency to overestimate the extension of forest surface area in the participants’ region, in Italy, and in the European Union. Results also showed high scores for participants’ perceived importance of environmental issues, such as climate change and biodiversity protection, and in their belief that forests could play a positive role in addressing these issues and providing important outcomes and benefits for the quality of human life, such as health and well-being or social cohesion.

Keywords: Forest Perceptions, Nature Experience, Environmental Attitudes, Environmental Issues

iForest 13 (4): 323-328 (2020) - doi: 10.3832/ifor3394-013
https://iforest.sisef.org/contents/?id=ifor3394-013

Review Papers: Remote sensing of selective logging in tropical forests: current state and future directions

Jackson CM, Adam E — 2020-07-10

Jackson CM, Adam E

REMOTE SENSING OF SELECTIVE LOGGING IN TROPICAL FORESTS: CURRENT STATE AND FUTURE DIRECTIONS

Abstract: This paper reviews and discusses the status of remote sensing techniques applied in detecting and monitoring selective logging disturbance in tropical forests. The analyses concentrated on the period 1992-2019. Accurate and precise detection of selectively logged sites in a forest is crucial for analyzing the spatial distribution of forest disturbances and degradation. Remote sensing can be used to monitor selective logging activities and associated forest fires over tropical forests, which otherwise requires labor-intensive and time-consuming field surveys, that are costly and difficult to undertake. The number of studies on remote sensing for selective logging has grown steadily over the years, thus, the need for their review so as to guide forest management practices and current research. A variety of peer reviewed articles are discussed so as to evaluate the applicability and accuracy of different methods in different circumstances. Major challenges with existing approaches are singled out and future needs are discussed.

Keywords: Tropical Forest Disturbance, Selective Logging, Forest Degradation, Forest Canopy Gaps, Disturbance Mapping, Remote Sensing, Forest Monitoring

iForest 13 (4): 286-300 (2020) - doi: 10.3832/ifor3301-013
https://iforest.sisef.org/contents/?id=ifor3301-013

Research Articles: Hydrological simulation of a small forested catchment under different land use and forest management

Oliveira LT, Cecílio RA, Zanetti SS, Loos RA, Bressiani DA, Srinivasan R — 2020-07-10

Oliveira LT, Cecílio RA, Zanetti SS, Loos RA, Bressiani DA, Srinivasan R

HYDROLOGICAL SIMULATION OF A SMALL FORESTED CATCHMENT UNDER DIFFERENT LAND USE AND FOREST MANAGEMENT

Abstract: This paper describes the assessment of the SWAT hydrological model to reproduce continuous daily streamflow and simulate scenarios of forest management for a small catchment under tropical climate in Aracruz, Brazil. The main land use of the catchment consisted of eucalyptus cultivation. The SWAT parameters were calibrated and validated using daily hydrologic and meteorological data from 1997 to 2004. The statistical indices of SWAT validation (NS = 0.74, PBIAS = -14.34%, RSR = 0.51) show that SWAT performance was satisfactory in this application. Different land use and forest management scenarios were simulated with the aim of assessing their influence over the streamflow. The scenarios were: catchment under eucalyptus cultivation with three different forest managements and catchment under the native forest (Atlantic Rainforest). The scenarios simulations did not show significant changes in the long-term average streamflow. Minimum, maximum, and average annual streamflows were higher for eucalyptus scenarios compared to the native forest scenario. These results should be carefully applied to other watersheds as they reflect soil, landscape, and climate characteristics, as well as the geographic location, size, and use of water of the plantings and other vegetation.

Keywords: Hydrological Modeling, Soil and Water Assessment Tool (SWAT), Atlantic Rainforest, Eucalyptus

iForest 13 (4): 301-308 (2020) - doi: 10.3832/ifor3221-013
https://iforest.sisef.org/contents/?id=ifor3221-013

Research Articles: The conversion into high forest of Turkey oak coppice stands: methods, silviculture and perspectives

2020-07-10

Manetti MC, Becagli C, Bertini G, Cantiani P, Marchi M, Pelleri F, Sansone D, Fabbio G

THE CONVERSION INTO HIGH FOREST OF TURKEY OAK COPPICE STANDS: METHODS, SILVICULTURE AND PERSPECTIVES

Abstract: The goal of this study is to assess the impact of different thinning approaches for coppice conversion into high forest of Turkey oak stands in Italy. The stand structure and the tree/shrub diversity were analyzed in 27 long-term monitoring plots from 7 experimental trials in the Colline Metallifere district (Tuscany, Central Italy) to verify the consistency of the original cultivation goals with the current stand structures. Three different approaches were applied from 1969 onwards: thinning from below, selective thinning, and no-management. Three indexes of specific diversity (Specific Richness, Shannon index and Importance Value) and two indexes of vertical diversity (Vertical Evenness and Coefficient of variation of tree height) were used to analyze and compare the outcome of management practices. The results showed a significantly higher dimensional variability and basal area, and a more complex vertical diversity in control plots and in the plots subject to selective thinning, as compared with plots subject to thinning from below. Tree species richness was high in all plots, independently of the thinning type applied. Based on our results, we suggest Turkey oak-dominated transitory stands to be initially managed by thinning from below, which is easy to be implemented and economically feasible. Selective thinning may be applied later with the aim of promoting sporadic but valuable tree species and increasing tree species diversity.

Keywords: Forest Monitoring, Thinning from Below, Selective Thinning, Biodiversity, Mediterranean Area

iForest 13 (4): 309-317 (2020) - doi: 10.3832/ifor3483-013
https://iforest.sisef.org/contents/?id=ifor3483-013

Research Articles: Decline in commercial pine nut and kernel yield in Mediterranean stone pine (Pinus pinea L.) in Spain

2020-07-03

Calama R, Gordo J, Mutke S, Conde M, Madrigal G, Garriga E, Arias MJ, Piqué M, Gandía R, Montero G, Pardos M

DECLINE IN COMMERCIAL PINE NUT AND KERNEL YIELD IN MEDITERRANEAN STONE PINE (PINUS PINEA L.) IN SPAIN

Abstract: Cones of the Mediterranean stone pine (Pinus pinea L.) constitute one of the most relevant non-wood forest products collected in the Mediterranean forests, providing high value edible kernels. In the last years it has been observed a severe decline in the kernel-per-cone yield (kg of kernels obtained from a kg of fresh cones) through the whole area of the species. This decline has been associated with both ongoing climate change and the recent expansion over the Mediterranean Basin of the Western Conifer Seed Bug, Leptoglossus occidentalis Heideman, an exotic pest which predates seeds of conifer species. In the present work we aimed to confirm and quantify the impact of this recent decline on pine nut and kernel production, identify the main factors provoking this reduction, and give evidence over causality by a potential biotic agent. We analysed recent and historical series of pine nut and kernel production obtained in the four main regions where Pinus pinea occurs in Spain. Our results showed a significant drop in the final kernel-per-cone yield on three of the four regions analysed, reaching reductions over 50% in the most affected areas. We observed that this reduction is mainly associated with a significant and generalised drop in the kernel-per-nut yield (kg of kernels per kg of pine nuts in shell), triggered by an increment in the rate of damaged pine nuts and, to a lesser extent, a reduction in the number of pine nuts per cone. The prevalence of this reduction on kernel-per-cone yield over different years and provenances with contrasting climate reinforces the hypothesis of the implication of a biotic factor which can be aggravated on extreme drought years.

Keywords: Leptoglossus occidentalis, Kernel-per-cone Yield, Cones, Exotic Pest, Seed Predation

iForest 13 (4): 251-260 (2020) - doi: 10.3832/ifor3180-013
https://iforest.sisef.org/contents/?id=ifor3180-013

Research Articles: Growth, morphology, and biomass allocation of recently planted seedlings of seven European tree species along a light gradient

Bebre I, Annighöfer P, Ammer C, Seidel D — 2020-07-03

Bebre I, Annighöfer P, Ammer C, Seidel D

GROWTH, MORPHOLOGY, AND BIOMASS ALLOCATION OF RECENTLY PLANTED SEEDLINGS OF SEVEN EUROPEAN TREE SPECIES ALONG A LIGHT GRADIENT

Abstract: Light is one of the most critical factors controlling tree survival and growth. Limited light availability induces phenotypic plasticity, thus enabling plants to adapt to suboptimal conditions. The plastic responses are species-specific and are thought to largely depend on species’ shade tolerance. This study aims to add to existing research by trying to disentangle the effects of light, species identity, and shade tolerance on growth, biomass partitioning, and morphology of seedlings of seven common European tree species. For that purpose, we set up a shading experiment where seedlings were grown under three levels of light availability (15%, 35%, and 100%). A destructive harvest was carried out for the assessment of biomass allocation and structural complexity of plant architecture after a year of exposure to limited light. The specific leaf area increased with decreasing light availability for all species. However, we found little to no changes in relative height and diameter growth, biomass allocation to aboveground tree compartments, and structural complexity along the light gradient. We argue that because trees were grown under open field conditions, both in the nursery and for the first year of the experiment, it might have resulted in a delayed response to limited light availability. Assuming the delayed reaction of less plastic plant organs, we expect that the morphological adaptations of the tree species and intra- and interspecific differences will become more pronounced, as the trees grow older.

Keywords: Shade Tolerance, Plant Morphology, Fractal Analysis, Biomass Allocation, Specific Leaf Area, Light

iForest 13 (4): 261-269 (2020) - doi: 10.3832/ifor3370-013
https://iforest.sisef.org/contents/?id=ifor3370-013

Research Articles: Species-specific morphological and physiological characteristics and progressive nitrogen limitation under elevated CO2 concentration

Song WK, Byeon SY, Lee H, Lee MS, Ryu D, Kang JW, Han SH, Oh CY, Kim HS — 2020-07-03

Song WK, Byeon SY, Lee H, Lee MS, Ryu D, Kang JW, Han SH, Oh CY, Kim HS

SPECIES-SPECIFIC MORPHOLOGICAL AND PHYSIOLOGICAL CHARACTERISTICS AND PROGRESSIVE NITROGEN LIMITATION UNDER ELEVATED CO2 CONCENTRATION

Abstract: Elevated atmospheric CO2 (eCO2) concentration initially enhances photosynthesis, growth and ecosystem productivity, but the excessive use of nitrogen due to the increased productivity causes uncertainty in long-term ecosystem responses. We exposed Korean red pine, Chinese ash, and Korean mountain ash to current atmospheric CO2 concentration (aCO2), 1.4 times higher CO2 concentration (eCO21.4), and 1.8 times higher CO2 concentration (eCO21.8) in an Open-Top Chamber (OTC) experiment for eight years (2010-2017) to investigate the effect on the morphological and physiological properties of trees. We also assessed whether nitrogen limitation occurred with time by comparing leaf and soil nitrogen concentration. CO2 fertilization effect was observed on tree growth for the first two years (p < 0.05), but there was no difference thereafter. For photosynthetic properties, CO2 effects were species-specific; no effects on Korean red pine and Chinese ash vs. significant effect on Korean mountain ash. However, maximum photosynthetic and carboxylation rates significantly decreased by 24.3% and 31.3% from 2013 to 2017, respectively. Leaf nitrogen significantly decreased by 21.0 % at eCO21.4 and 18.5 % at eCO21.8 compared with aCO2 treatment. This study showed the decline of leaf nitrogen and species-specific responses to long-term high CO2 concentration, which will effect on species competition and ecosystem succession.

Keywords: Elevated CO2, Photosynthetic Properties, Down-regulation, Progressive Nitrogen Limitation, Carbon dioxide

iForest 13 (4): 270-278 (2020) - doi: 10.3832/ifor3288-013
https://iforest.sisef.org/contents/?id=ifor3288-013

Research Articles: Influences of mature Pinus nigra plantations on the floristic-vegetational composition along an altitudinal gradient in the central Apennines, Italy

Allegrezza M, Pesaresi S, Ballelli S, Tesei G, Ottaviani C — 2020-07-03

Allegrezza M, Pesaresi S, Ballelli S, Tesei G, Ottaviani C

INFLUENCES OF MATURE PINUS NIGRA PLANTATIONS ON THE FLORISTIC-VEGETATIONAL COMPOSITION ALONG AN ALTITUDINAL GRADIENT IN THE CENTRAL APENNINES, ITALY

Abstract: Plantations of conifers are widespread in Europe, often occurring outside of their native range. Reduction in species richness linked to increases in altitude has been previously reported for natural forests, although there is a lack of specific studies for mature pine plantations in both the Apennines and Europe. The aim of this study was to quantify the long-term effects of the extensive Pinus nigra plantations carried out between 1900 and 1956 in protected areas on floristic richness, species composition, and ecological traits of the understorey vegetation. We compared 20 mature pine plantations selected along an altitudinal gradient (700-1700 m a.s.l.) with neighbouring deciduous natural forests dominated by Ostrya carpinifolia and Fagus sylvatica, which represent the most widespread forest types in the central Apennines. The results showed that floristic richness follows two distinct altitude trends in pine plantations and natural forests. A strong reduction in species richness with elevation was observed in the natural forests, as well as a consequent increase in the local contribution to beta diversity, with a turnover of the ecological traits of the species. Contrastingly, no significant changes in richness and beta diversity were found for pine plantations in the same altitude range. Indeed, mature pine plantations up to 1400-1500 m a.s.l. showed the presence of many heliophilous and thermophilous species that are usually distributed at lower elevation. We discuss how such pine plantations can mitigate the effect of increasing altitude which is usually observed in the natural forests, slowing down the typical diversification of the forest communities along the altitudinal gradient.

Keywords: Pinus nigra Plantations, Forest Origin, Richness, Beta-diversity, Altitudinal Gradient, Canopy Filter, Protected Areas, Apennines

iForest 13 (4): 279-285 (2020) - doi: 10.3832/ifor3215-013
https://iforest.sisef.org/contents/?id=ifor3215-013

Research Articles: Measured and modelled source water δ18O based on tree-ring cellulose of larch and pine trees from the permafrost zone

2020-06-19

Churakova-Sidorova OV, Lienert S, Timofeeva G, Siegwolf R, Roden J, Joos F, Saurer M

MEASURED AND MODELLED SOURCE WATER δ18O BASED ON TREE-RING CELLULOSE OF LARCH AND PINE TREES FROM THE PERMAFROST ZONE

Abstract: To identify source water for trees growing on permafrost in Siberia, we applied mechanistic models that quantify physical and biochemical fractionation processes, leading to oxygen isotope variation (δ18O) in plant organic matter. These models allowed us to investigate the influence of a variety of climatic factors on tree-ring cellulose from two dominant species: Larix cajanderi Mayr. from northeastern Yakutia (69° 22′ N, 148° 25′ E, ~ 250 m a.s.l.) and Pinus sylvestris L. from Central Yakutia (62°14′ N, 129°37′ E, ~ 220 m a.s.l.). The climate of the region is highly continental with short growing seasons, low amount of precipitation and these forest ecosystems are growing on permafrost, which in turn impact the water cycle and climate variation in the δ18O of source water. We compared outputs of the Land surface Processes and eXchanges (LPX-Bern v. 1.3), and Roden-Lin-Ehleringer (RLE) models for the common period from 1945 to 2004. Based on our findings, trees from northeastern and central Yakutia may have access to additional thawed permafrost water during dry summer periods. Owing to differences in the soil structure, active thaw soil depth and root systems of trees at two Siberian sites, Larix cajanderi Mayr. trees can access water not more than from 50 cm depth, in contrast to Pinus sylvestris L. in Central Yakutia which can acquire water from up to 80 cm soil depth. The results enhance our understanding of the growth and survival of the trees in this extreme environment.

Keywords: Conifers, Climate, Drought, Permafrost Thaw Depth, Siberia, δ18O of Source Water

iForest 13 (3): 224-229 (2020) - doi: 10.3832/ifor3212-013
https://iforest.sisef.org/contents/?id=ifor3212-013

Research Articles: Local ecological niche modelling to provide suitability maps for 27 forest tree species in edge conditions

Stephan J, Bercachy C, Bechara J, Charbel E, López-Tirado J — 2020-06-19

Stephan J, Bercachy C, Bechara J, Charbel E, López-Tirado J

LOCAL ECOLOGICAL NICHE MODELLING TO PROVIDE SUITABILITY MAPS FOR 27 FOREST TREE SPECIES IN EDGE CONDITIONS

Abstract: Ecological Niche Modelling (ENM) portrays the relationship between the actual geographical distribution of a species and the environmental factors that induced this distribution. Yet most models study species over the wider range of their distribution; thus, they are rarely appropriate for forest management and forest restoration on the local scale. This study aims to understand the major environmental factors affecting the distribution of 27 species, through limiting ENM at national level (Lebanon). MaxENT software was used for modelling. Area under the curve (AUC) values showed a very good robustness of the models. Minimal biogeographic and climatic parameters such as elevation, distance from the sea, annual mean precipitation, the average minimum temperature of the coldest month, the average maximum temperature of the warmest month, and Emberger Quotient were sufficient to obtain robust modelling results. Cloud coverage during summer was identified as a novelty factor explaining species distribution at the edge of their range. Composite soil and topography predictors such as Potential Direct Incident Radiation (PDIR) and the Integrated Moisture Index (IMI) were reduced to simple factors such as aspect, slope and available water content, whose contribution was conditioned to higher data resolution. The high number of presence points enabled us to study the range of species distribution gathering them according to their ecological characteristics. The generated reforestation suitability maps and the likelihood of occurrence of each species were achieved to define priority species for conservation and forest management. This information could be useful for decision-makers and foresters.

Keywords: Ecological Niche Modelling, Suitability Maps, Cloud Coverage, Range of Distribution, MaxEnt

iForest 13 (3): 230-237 (2020) - doi: 10.3832/ifor3331-013
https://iforest.sisef.org/contents/?id=ifor3331-013

Research Articles: Verticillium wilt of Ailanthus altissima in Italy caused by V. dahliae: new outbreaks from Tuscany

2020-06-19

Pisuttu C, Marchica A, Bernardi R, Calzone A, Cotrozzi L, Nali C, Pellegrini E, Lorenzini G

VERTICILLIUM WILT OF AILANTHUS ALTISSIMA IN ITALY CAUSED BY V. DAHLIAE: NEW OUTBREAKS FROM TUSCANY

Abstract: Verticillium spp., including V. nonalfalfae and V. dahliae, are known vascular wilt pathogens of the invasive Ailanthus altissima (tree-of-heaven) in the United States and in Europe. Herein we provide evidence of the presence of a previously unreported wilt disease of A. altissima in Tuscany (Central Italy). Several isolates were collected from two locations and identified as V. dahliae, based on microscopical features of conidiophores, conidia and microsclerotia. Genomic DNA was extracted from the mycelium, the ITS region was amplified and the sequence was deposited in GenBank as VdGL16 (accession no. MK474459). BLASTn analysis showed 100% similarity with V. dahliae. To confirm pathogenicity of VdGL16, inoculations of Ailanthus seedlings were performed with the root dipping technique whereas mature trees were stem-inoculated. All inoculated seedlings exhibited wilt symptoms after 20 days, while mature Ailanthus trees showed wilting and dieback after six months. The pathogen was easily re-isolated from seedlings and re-identified as V. dahliae, thus satisfying Koch’s postulates. Results from intraspecific resistance screening of nine seed sources from across Italy revealed that Ailanthus provenances from all the six sampled regions were susceptible to V. dahliae. Stem inoculated adult plants exhibited abundant production of epicormic sprouts along the stem within six months, and most of these sprouts wilted following initial dieback of the main stem; furthermore, sprouting from the crown was intense. Petioles and rachises tissues of leaves fallen from infected trees were a good source for re-isolation of the pathogen; we proved that such petioles and rachises can effectively transfer the fungus to healthy Ailanthus seedlings via root infections. Host-specificity of the V. dahliae isolate VdGL16 was also determined on 40 non-target species/varieties/cultivars. The isolate caused disease in herbaceous species belonging to five botanical families: Asteraceae, Lamiaceae, Leguminoseae, Linaceae and Solanaceae. Given the difficulties in countering Ailanthus invasion with mechanical and chemical methods, the biological control using Verticillium may provide an efficient, low cost and sustainable control of this invasive species.

Keywords: Tree-of-heaven, Verticillium dahliae, ITS Region, Accession Number MK474459, Koch’s Postulates, Biocontrol

iForest 13 (3): 238-245 (2020) - doi: 10.3832/ifor3238-013
https://iforest.sisef.org/contents/?id=ifor3238-013

Short Communications: Assessing Pinus pinea L. resilience to three consecutive droughts in central-western Italian Peninsula

Piraino S — 2020-06-19

Piraino S

ASSESSING PINUS PINEA L. RESILIENCE TO THREE CONSECUTIVE DROUGHTS IN CENTRAL-WESTERN ITALIAN PENINSULA

Abstract: Climate projections for the Mediterranean area forecast drier and hotter conditions and increasing trend in extreme climatic events such as drought. Scientific evidences reported that extreme dry spells affected the stem growth of different Mediterranean low-elevational pine forests inducing a decrease in tree resilience, defined as the capacity to resist to environmental stress and to recover pre-disturbance functioning. Despite its ecological and economic importance, thus far no study examined Pinus pinea L. (stone pine) resilience to drought events. This research reconstructed stone pine resilience by considering resistance, recovery, and the proportion of trees showing high values of both indexes of several planted stands to three consecutive spring-summer droughts occurred during the second half of the 20th century. Local climatic conditions during dry spells modulated the species resistance and recovery. In this sense, wetter conditions promoted recovery, whereas warmer spring-summer affected stone pine resistance. Moreover, spring rather than summer droughts influenced stone pine resistance and recovery, confirming the species sensitivity to climatic conditions at the beginning of the growing season. Results indicated that while recovery did not significantly changed, the species resistance diminished along the analyzed period. Furthermore, more than 60% of the examined trees were not able to reach pre-drought growth, suggesting a moderate resilience of P. pinea to adverse climatic conditions. The results contribute to improve our understanding of stone pine growth dynamics in the climate-change context of increasing aridity actually occurring in the Mediterranean area, providing useful information for the sustainable management of these natural resources.

Keywords: Climate Change, Disturbance, Dry Spell, Tree Growth

iForest 13 (3): 246-250 (2020) - doi: 10.3832/ifor3320-013
https://iforest.sisef.org/contents/?id=ifor3320-013

Short Communications: Multi-aged micro-neighborhood patches challenge the forest cycle model in primeval European beech

Zenner EK, Peck JE, Trotsiuk V — 2020-06-06

Zenner EK, Peck JE, Trotsiuk V

MULTI-AGED MICRO-NEIGHBORHOOD PATCHES CHALLENGE THE FOREST CYCLE MODEL IN PRIMEVAL EUROPEAN BEECH

Abstract: As currently framed, the forest cycle model that underlies close-to-nature management in temperate beech forests throughout the globe specifies an orderly sequence of temporal development within even-aged patches comprising the forest mosaic. Although this model has been widely applied to European beech (Fagus sylvatica L.) forests, the underlying assumptions of disturbance-induced even-agedness (i.e., within-patch age homogeneity) and competition-induced size differentiation (i.e., within-patch size heterogeneity) have not been tested in natural beech forests due to prohibitions on tree coring in primeval forest reserves. In a rare and unprecedented test dataset of spatially explicit tree ages in an old-growth European beech forest, we employed triangulated irregular networks of Delaunay triangles to objectively identify natural tree neighborhoods to determine if neighboring (i.e., within-patch) trees were even- or, at most, two-aged. Age differences among neighboring trees (summarized in 25-yr age classes) were rarely <25 yrs and mostly >50 yrs, while the few "even-aged" patches were very small (100 m2) and relatively young (<150 yrs). In this first assessment of the assumptions underlying the forest cycle model in European beech, we observed neither the even-aged cohorts expected for disturbance-induced patches in different phases of development, nor the size differentiation among similarly aged trees that should arise from the neighborhood dynamics of competition, self-thinning, and growth. The lack of patches indicating demographic turnover is fundamentally inconsistent with the forest cycle model as it is currently framed. We call for further exploration of spatially-explicit tree age datasets to determine the generality of these observations.

Keywords: Age Reconstruction, Carpathians, Dendrochronology, Development Stage, Forest Cycle, Stand Development, Structure, Triangulated Irregular Network (TIN)

iForest 13 (3): 209-214 (2020) - doi: 10.3832/ifor3309-013
https://iforest.sisef.org/contents/?id=ifor3309-013

Research Articles: A bark beetle infestation predictive model based on satellite data in the frame of decision support system TANABBO

2020-06-06

Duračiová R, Muňko M, Barka I, Koreň M, Resnerová K, Holuša J, Blaženec M, Potterf M, Jakuš R

A BARK BEETLE INFESTATION PREDICTIVE MODEL BASED ON SATELLITE DATA IN THE FRAME OF DECISION SUPPORT SYSTEM TANABBO

Abstract: The European spruce bark beetle Ips typographus L. causes significant economic losses in managed coniferous forests in Central and Northern Europe. New infestations either occur in previously undisturbed forest stands (i.e., spot initiation) or depend on proximity to previous years’ infestations (i.e., spot spreading). Early identification of newly infested trees over the forested landscape limits the effective control measures. Accurate forecasting of the spread of bark beetle infestation is crucial to plan efficient sanitation felling of infested trees and prevent further propagation of beetle-induced tree mortality. We created a predictive model of subsequent year spot initiation and spot spreading within the TANABBO decision support system. The algorithm combines open-access Landsat-based vegetation change time-series data, a digital terrain model, and forest stand characteristics. We validated predicted susceptibility to bark beetle attack (separately for spot initiation and spot spreading) against beetle infestations in managed forests in the Bohemian Forest in the Czech Republic (Central Europe) in yearly time steps from 2007 to 2010. The predictive models of susceptibility to bark beetle attack had a high degree of reliability (area under the ROC curve - AUC: 0.75-0.82). We conclude that spot initiation and spot spreading prediction modules included within the TANABBO model have the potential to help forest managers to plan sanitation felling in managed forests under pressure of bark beetle outbreak.

Keywords: Spatial Predictive Model, Bark Beetle Infestation, GIS, ROC Curve, Norway Spruce

iForest 13 (3): 215-223 (2020) - doi: 10.3832/ifor3271-013
https://iforest.sisef.org/contents/?id=ifor3271-013

Research Articles: Climate impacts on tree growth in a Neotropical high mountain forest of the Peruvian Andes

Rodríguez-Morata C, Madrigal-González J, Stoffel M, Ballesteros-Cánovas JA — 2020-05-19

Rodríguez-Morata C, Madrigal-González J, Stoffel M, Ballesteros-Cánovas JA

CLIMATE IMPACTS ON TREE GROWTH IN A NEOTROPICAL HIGH MOUNTAIN FOREST OF THE PERUVIAN ANDES

Abstract: Global warming can jeopardize important ecosystem functions and services in sensitive Neotropical mountain areas. However, untangling the relative roles of natural climate variability pattern from current global warming trends still represent a major challenge. Here, we propose a novel analytical approach based on Structural Equation Models to evaluate the relative roles of different sources of climate variability on tree growth. Specifically, we investigate direct and indirect linkages between Basal Area Increments (BAI) and a set of different climatic sources of variability, such as: (i) large-scale atmospheric oscillation patterns (i.e., the El Niño Southern Oscillation, ENSO and the Pacific Decadal Oscillation, PDO); and (ii) local meteorology in terms of temperature and precipitation. Additionally, we included in the SEM framework other important variables such as: (iii) calendar year (representative of temporal linear trends); and (iv) tree size (representative of main biological trends). Results indicate that the ENSO and PDO modulate minimum temperatures (Tmin) in the study area. These indices describe the oscillating behavior of the climatic modes (i.e., South Oscillation Index and PDO index) and are negatively correlated with Tmin. As such, they also influence tree growth (represented here by BAI) indirectly. Furthermore, through its direct impact on Tmin increase, ongoing climate warming has an indirect negative effect on BAI, thereby implying that the ongoing temperature rise could exert control on productivity in high mountain forests of the Andes, and that this influence could become more important with continued temperature increase.

Keywords: Global Warming, Tree Growth Variability, Podocarpus glomeratus Don., Andean Forest, Peru, Structural Equation Model (SEM)

iForest 13 (3): 194-201 (2020) - doi: 10.3832/ifor3124-013
https://iforest.sisef.org/contents/?id=ifor3124-013

Research Articles: Typology and synecology of aspen woodlands in the central-southern Apennines (Italy): new findings and synthesis

Russo G, Pedrotti F, Gafta D — 2020-05-19

Russo G, Pedrotti F, Gafta D

TYPOLOGY AND SYNECOLOGY OF ASPEN WOODLANDS IN THE CENTRAL-SOUTHERN APENNINES (ITALY): NEW FINDINGS AND SYNTHESIS

Abstract: In order to review and complete our knowledge of the typology and synecology of the aspen communities from the central-southern Apennines, ten original relevés were performed on the Gargano plateau and a set of 35 relevés assigned to four community types (HP: Holco mollis-Populetum tremulae; MP: Melico uniflorae-Populetum tremulae; FP: Fraxino orni-Populetum tremulae; GP: Geranio versicoloris-Populetum tremulae) were assembled from literature. These relevés along with several environmental variables either measured or estimated were involved in cluster and ordination analyses. The relevés from Gargano formed a distinctive cluster and were assigned to a new community type (SP: Stellario holosteae-Populetum tremulae ass. nova), which can be considered an Adriatic synvicariant of HP that is distributed in similar habitats (doline bottoms) but on the Tyrrhenian escarpment. At low levels of floristic similarity, the grouping of relevés in two clusters induces a sharp separation between the aspen communities distributed in the central Apennines (MP and FP) and those from the southern Apennines (SP, HP and GP), which is mainly due to compositional differences in the regional species pool. The ordination scores of relevés were best related to terrain slope, soil nitrogen, elevation, air temperature, light availability and, to a lesser extent, to soil moisture and reaction. Unlike MP and GP that appear the most mesophilous, the FP stands display a slightly more xerophilous and acidophilous character induced by the steeper slopes on which they occur. The HP habitat is the driest and lightest very likely because of the open overlying canopy, in contrast to MP stands featuring a high shrub cover. The highest occurrence of nitrophilous species was observed in SP and MP. The management of these pioneer woods should be aimed at conservation, as they play an important role in the recovery of forest herb diversity along the ecological succession towards hardwood forests.

Keywords: Differential Species, Distribution Area, Environmental Variable Fitting, Gargano, Multivariate Analyses, Phytosociologic Classification, Secondary Succession, Stellario holosteae-Populetum tremulae

iForest 13 (3): 202-208 (2020) - doi: 10.3832/ifor3315-013
https://iforest.sisef.org/contents/?id=ifor3315-013

Research Articles: Verification of new Populus nigra L. clone improvement based on their performance over three rotations

Novotná K, Štochlová P, Benetka V — 2020-05-12

Novotná K, Štochlová P, Benetka V

VERIFICATION OF NEW POPULUS NIGRA L. CLONE IMPROVEMENT BASED ON THEIR PERFORMANCE OVER THREE ROTATIONS

Abstract: Populus nigra is an important autochthonous woody plant that can be grown as a renewable energy source. The possibility of its improvement through intraspecific hybridization was tested. Differences in biomass production, growth parameters, Melampsora larici-populina rust resistance and drought tolerance were evaluated among 19 intraspecific hybrids from controlled crosses, 2 clones selected from natural populations and the “MAX 4” clone (P. nigra × P. maximowiczii). These P. nigra clones from controlled crosses were chosen from more than 2000 hybrid individuals whose parents were selected from natural populations in the Czech Republic. A field trial was set up in Pruhonice, Czech Republic (320 m a.s.l., 591 mm rainfall annually, mean annual temperature of 9.5 °C). The planting density was 6061 plants ha-1, and the plants were coppiced three times at 3-year intervals. The trial was irrigated only during its establishment. Among the clones, significant differences were found in all the evaluated traits over three rotations. An average dry matter yield of the best clone “MAX 4” was 12.8 t ha-1 yr-1 over three harvests. The best black poplar clone reached up to 9.4 t ha-1 yr-1 in three harvests. Rust resistance was constant over 9 years and high for the three P. nigra clones (two from controlled crosses and one from natural populations). Moreover, the best P. nigra clones from controlled crosses showed higher drought tolerance than the “MAX 4” clone. Breeding progress was confirmed, and most of the P. nigra clones from controlled crosses performed better than the clones selected from natural populations. The trial validated the suitability of natural populations for use as gene sources for intraspecific hybridization and as sources of clones with traits comparable with those of interspecific clones. These new P. nigra clones can replace allochthonous clones in areas where autochthonous P. nigra populations are threatened by introgression.

Keywords: Plant Breeding, Black Poplar, Intraspecific Hybridization, Short Rotation Coppice Culture, Melampsora larici-populina, Biomass Production, Tree Regeneration

iForest 13 (3): 185-193 (2020) - doi: 10.3832/ifor3171-013
https://iforest.sisef.org/contents/?id=ifor3171-013

Review Papers: Ensuring future regeneration success of Qualea grandiflora Mart. (Vochysiaceae) in neotropical savanna (cerrado) biomes by reviewing the available information and identifying research gaps

Da Ponte G, Huth F, Wagner S — 2020-05-02

Da Ponte G, Huth F, Wagner S

ENSURING FUTURE REGENERATION SUCCESS OF QUALEA GRANDIFLORA MART. (VOCHYSIACEAE) IN NEOTROPICAL SAVANNA (CERRADO) BIOMES BY REVIEWING THE AVAILABLE INFORMATION AND IDENTIFYING RESEARCH GAPS

Abstract: Qualea grandiflora Mart. (Vochysiaceae) is one of the most widespread species within the cerrado formation, which counts amongst the most threatened ecosystems worldwide. Understanding the regeneration ecology of Q. grandiflora is a central requirement for the success of conservation measures and silvicultural management strategies. Exhaustive investigation was carried out into each of the development stages, and the connected processes within the regeneration cycle, to provide a better understanding of the main factors influencing the regeneration ecology and the recruitment dynamics of the species. For this purpose, we analysed 92 different sources of information in this review, divided into two groups (n = 41 with “basic species information” and n = 51 with “specific information about regeneration stages and processes”) relevant for regeneration and silviculture. Our literature review showed the high proportion of studies addressing the processes flowering, pollination and fruiting, whereas the subsequent processes like seed dispersal, seed storage, germination and seedling development are almost entirely lacking. This also applies for spatial information about environmental conditions and the related regeneration processes in Q. grandiflora. This knowledge is important for management, for example, knowledge of the critical distances between flowering and seed producing trees to ensure genetically diverse regeneration and the identification of safe sites for seedling establishment. Most of the practical suggestions in relation to increasing densities or growth of Q. grandiflora seedlings and saplings made in the literature are linked to less intensive fire management strategies adopted at certain times. The use of selective herbivory to reduce the increasing competition pressure exerted by invasive grasses and hampering Q. grandiflora seedlings is also cited. In this study we highlight the need for more complex species-specific information following the development stages and processes of the regeneration cycle so as to prepare a continuous strategy with a range of management approaches.

Keywords: Cerrado Formations, Environmental Influences, Regeneration Cycle, Silvicultural Management Strategies

iForest 13 (3): 154-164 (2020) - doi: 10.3832/ifor2684-013
https://iforest.sisef.org/contents/?id=ifor2684-013

Research Articles: Allometric equations to estimate above-ground biomass of small-diameter mixed tree species in secondary tropical forests

2020-05-02

Puc-Kauil R, Ángeles-Pérez G, Valdéz-Lazalde JR, Reyes-Hernández VJ, Dupuy-Rada JM, Schneider L, Pérez-Rodríguez P, García-Cuevas X

ALLOMETRIC EQUATIONS TO ESTIMATE ABOVE-GROUND BIOMASS OF SMALL-DIAMETER MIXED TREE SPECIES IN SECONDARY TROPICAL FORESTS

Abstract: Accounting for small-size tree biomass is critical to improve total stand biomass estimates of secondary tropical forests, and is essential to quantify their vital role in mitigating climate change. However, owing to the scarcity of equations available for small-size trees, their contribution to total biomass is unknown. The objective of this study was to generate allometric equations to estimate total biomass of 22 tree species ≤ 10 cm in diameter at breast height (DBH), in the Yucatan peninsula, Mexico, by using two methods. First, the additive approach involved the development of biomass equations by tree component (stem, branch and foliage) with simultaneous fit. In the tree-level approach, total tree biomass equations were fit for multi-species and wood density groups. Further, we compared the performance of total tree biomass equations that we generated with multi-species equations of previous studies. Data of total and by tree component biomass were fitted from eight non-linear models as a function of DBH, total height (H) and wood density (ρ). Results showed that two models, identified as model I and II, best fitted our data. Model I has the form AGB = β0 (ρ·DBH2·H)β1 + ε and model II: AGB = exp(-β0)(DBH2·H)β1 + ε, where AGB is biomass (kg). Both models explained between 53% and 95% of the total observed variance in biomass, by tree-structural component and total tree biomass. The variance of total tree biomass explained by fit models related to wood density group was 96%-97%. Compared foreign equations showed between 30% and 45% mean error in total biomass estimation compared to 0.05%-0.36% error showed by equations developed in this study. At the local level, the biomass contribution of small trees based on foreign models was between 24.38 and 29.51 Mg ha-1, and model I was 35.97 Mg ha-1. Thus, from 6.5 up to 11.59 Mg ha-1 could be excluded when using foreign equations, which account for about 21.8% of the total stand biomass. Local equations provided more accurate biomass estimates with the inclusion of ρ and H as predictors variables and proved to be better than foreign equations. Therefore, our equations are suitable to improve the accuracy estimates of carbon forest stocks in the secondary forests of the Yucatan peninsula.

Keywords: Species Diversity, Biomass-carbon Stocks, Additive Equations, Simultaneous Fit, Wood Density Groups

iForest 13 (3): 165-174 (2020) - doi: 10.3832/ifor3167-013
https://iforest.sisef.org/contents/?id=ifor3167-013

Research Articles: Evaluation of urban forest landscape health: a case study of the Nanguo Peach Garden, China

Zhao Q, Tang HH, Gao CJ, Wei YH — 2020-05-02

Zhao Q, Tang HH, Gao CJ, Wei YH

EVALUATION OF URBAN FOREST LANDSCAPE HEALTH: A CASE STUDY OF THE NANGUO PEACH GARDEN, CHINA

Abstract: Urban forests are important as they provide recreation areas and offer ecological services. Both functions determine the status of an urban forest and reflect contradictory aspects of forest tourism development and environment conservation. However, assessment of urban forest health status at a landscape scale remains scarce. Here, we selected the Nanguo Peach Garden, China, as the study area. Urban forest health status at the landscape scale were classified into recreation and eco-conservation services. Sustainability was quantified using the principal component analysis and the Kriging method to map the landscape classification in the study area. With regard to landscape recreation sustainability, some 18.9% of the total study region was classified as “very good”. They were mainly distributed in the north, southwest, and southeast parts of the study area. The central and southeast regions, accounting for 9.5% of the total area, were classified as “very good” for eco-conservation sustainability. Regarding landscape health, the region classified as “very good” accounted for 11.1% of the total study area, and it was mainly distributed in the southern part of the area; the region classified as “very poor” accounted for 16.4% of the total area, and it was located in the northwestern and eastern parts of the study area. With improved landscape health status, the forest/non-forest patch area ratio was increased and the patch number ratio was decreased. A landscape was considered the healthiest when the forest/ non-forest area ratio was 0.65 and the patch number was 0.48. The spatial distribution of landscape recreation sustainability and eco-conservation sustainability differed in the Nanguo Peach Garden, and a close relationship was observed between the landscape health and forest landscape internal structure. Forest/non-forest patch area ratios and patch number ratios were relatively stable and constant, suggesting the urban forest landscapes were healthy. The healthiest forest landscapes were mainly distributed in the forest/non-forest transition zone and the unhealthiest forest landscape was mainly located in a single natural forest.

Keywords: Eco-conservation Sustainability, Landscape Recreation Sustainability, Patch Area Ratio, Patch Number Ratio, Urban Forest Landscape

iForest 13 (3): 175-184 (2020) - doi: 10.3832/ifor3206-013
https://iforest.sisef.org/contents/?id=ifor3206-013

Book Reviews: “Models of tree and stand dynamics”: a differential journey through forest modelling

Marano G, Collalti A — 2020-04-16

Marano G, Collalti A

“MODELS OF TREE AND STAND DYNAMICS”: A DIFFERENTIAL JOURNEY THROUGH FOREST MODELLING

Abstract: Quia pulvinar in id habitasse mi orci augue sollicitudin reprehenderit, officiis nisi, vivamus tempore, lorem quos? Lacinia cursus, sed, nascetur, tristique fusce, molestie unde, saepe mi dapibus metus! Perferendis blanditiis curabitur laborum possimus, a, non wisi commodi condimentum? Explicabo hac. Ultricies harum, mauris similique. Occaecat, taciti! Cursus tempus mollis maxime, officia consectetuer tempus vitae magna luctus sapiente nostra officia lacus! Corrupti quaerat deserunt. Id. Omnis et fusce dolores lacinia ea itaque hendrerit, urna. Senectus, voluptate taciti praesent pharetra, congue facilisis.

Keywords: Xxx, Xxx, Xxx, Xxx, Xxx

iForest 13 (2): 152-153 (2020) - doi: 10.3832/ifor0061-013
https://iforest.sisef.org/contents/?id=ifor0061-013

Review Papers: A review of the performance of woody and herbaceous ornamental plants for phytoremediation in urban areas

Capuana M — 2020-04-14

Capuana M

A REVIEW OF THE PERFORMANCE OF WOODY AND HERBACEOUS ORNAMENTAL PLANTS FOR PHYTOREMEDIATION IN URBAN AREAS

Abstract: Urban and periurban areas are often contaminated by several pollutants. Phytoremediation is considered to be an effective and eco-friendly strategy for the restoration of these contaminated lands. For this purpose, the exploitation of ornamental plants could be an additional option, due to their positive impact on the landscape. In this paper, we reviewed a selection of species which have been proposed for utilization in phytoremediation. Several tree species have been introduced in the past into urban environments for parks, gardens and avenues, with a selection studied for their capacity to absorb, tolerate, and translocate contaminants. Shrubby and herbaceous species are also commonly exploited for their ornamental features and are now studied for phytoremediation purposes. The responses of several effective species to the presence of heavy metals or dangerous organic compounds in the growth substrate are examined in this paper.

Keywords: Environment, Heavy Metals, Landscape, Organics, Pollution

iForest 13 (2): 139-151 (2020) - doi: 10.3832/ifor3242-013
https://iforest.sisef.org/contents/?id=ifor3242-013

Review Papers: Wood anatomy of boreal species in a warming world: a review

Zhang S, Belien E, Ren H, Rossi S, Huang JG — 2020-04-09

Zhang S, Belien E, Ren H, Rossi S, Huang JG

WOOD ANATOMY OF BOREAL SPECIES IN A WARMING WORLD: A REVIEW

Abstract: Global warming is affecting tree growth and forest productivity, especially in the Northern boreal ecosystems. Wood quality, which is largely determined by anatomical traits of wood, is vital for the forest industry and global carbon sequestration. Cambium activity, wood density, fiber length and microfibril angle are the anatomical traits that determine wood quality, depending on market demands. Within the global warming scenario, a comprehensive understanding of these traits is still lacking and urgently required for both the forest industries and ecological researches. In this review, we identify that large proportions of mature wood, high wood density, longer fiber or tracheid length and low microfibril angles are the anatomical traits closely related with high wood quality. Higher temperatures could trigger onset and ending of cambial cell division, thus affecting wood quality by modulating duration of the growing season. Climate warming could also affect wood quality by impacting earlywood and latewood formation, as well as changing wood density, fiber length and microfibril angle depending on different species and growing conditions. In addition, this review indicates that the anatomical traits involved in wood quality are diverse and depend on the intended use. Improving our knowledge about the underlying mechanisms of how the wood anatomical traits respond to a changing environment with extreme climate events is thus still a crucial topic in the forest sciences. Selection of species and provenances best adapted to climate warming will be necessary to improve quality without sacrificing volume. Studies on wood traits and their relation to climate should therefore focus on a multitude of aspects including the physiology and genetics of boreal tree species.

Keywords: Climate Warming, Earlywood, Fiber Length, Latewood, Microfibril Angle, Radial Growth, Wood Formation

iForest 13 (2): 130-138 (2020) - doi: 10.3832/ifor3230-013
https://iforest.sisef.org/contents/?id=ifor3230-013

Research Articles: Influences of forest gaps on soil physico-chemical and biological properties in an oriental beech (Fagus orientalis L.) stand of Hyrcanian forest, north of Iran

Amolikondori A, Vajari KA, Feizian M, Di Iorio A — 2020-04-07

Amolikondori A, Vajari KA, Feizian M, Di Iorio A

INFLUENCES OF FOREST GAPS ON SOIL PHYSICO-CHEMICAL AND BIOLOGICAL PROPERTIES IN AN ORIENTAL BEECH (FAGUS ORIENTALIS L.) STAND OF HYRCANIAN FOREST, NORTH OF IRAN

Abstract: Understanding the effects of silvicultural practices including single-tree selection on soil properties is essential for forest management in temperate broadleaved beech forests. Changes in physico-chemical and biological soil properties in 15 harvest-created gaps under single-tree selection and the adjacent closed canopies, with five replications for each, were studied 6 years after gap creation in an oriental beech (Fagus orientalis L.) stand of the Hyrcanian forest. Gaps were classified into three size classes: small (85-130 m2), medium (131-175 m2) and large (176-300 m2). Soil cores were collected at the center and at the edge of gaps, and under the adjacent closed canopy. Results indicated that gap size significantly affected soil texture and bulk density, whereas soil organic carbon (SOC), total nitrogen and pH showed a significant gradient from the center to the edge of gap independently form their size. SOC and total nitrogen at the center of gaps were also significantly lower than closed-canopy, in particular for the medium-gap; contrastingly, the bulk density with the highest mean value was found at the center of the large-gap. Gap size had no significant influence on soil microbial biomass. These results highlighted that similar conditions in terms of many soil properties were still present among gaps and adjacent closed-canopy stands six years after logging, though canopy openness triggered a reduction in carbon and nitrogen availability along with the related microbial activity at the center of gaps, independently from their size. Therefore, if aimed at preserving an uneven aged structure along with soil quality in temperate broadleaved deciduous forest as the oriental beech stands in the Hyrcanian region, single-tree selection practice for harvesting trees can be recommended as sustainable forest management type.

Keywords: Artificial Gap, Oriental Beech, Temperate Forests, Soil Properties

iForest 13 (2): 124-129 (2020) - doi: 10.3832/ifor3205-013
https://iforest.sisef.org/contents/?id=ifor3205-013

Research Articles: Using field and nursery treatments to establish Quercus suber seedlings in Mediterranean degraded shrubland

Muñoz-Rengifo J, Chirino E, Cerdán V, Martínez J, Fosado O, Vilagrosa A — 2020-03-26

Muñoz-Rengifo J, Chirino E, Cerdán V, Martínez J, Fosado O, Vilagrosa A

USING FIELD AND NURSERY TREATMENTS TO ESTABLISH QUERCUS SUBER SEEDLINGS IN MEDITERRANEAN DEGRADED SHRUBLAND

Abstract: Cork oak (Quercus suber L.) is a suitable species for restoring Mediterranean ecosystems due to its capacity to resprout after wildfires and its economic importance for the use of cork. Several studies have focused on improving the seedling quality and abiotic conditions at the outplanting site to favour the field performance of Q. suber, however, most studies have been conducted by independently testing treatments. The aim of this study was to assess the combined effect of three techniques that focused on reforestation success with Q. suber in Mediterranean degraded shrubland: (i) a nursery technique to improve root system development, such as the use of deep containers to develop a longer tap root, combined with two field techniques such as (ii) the use of tree shelters to diminish solar radiation stress, and (iii) shrubland treatments to reduce competition for soil water and nutrients. For this purpose, 1-year-old Q. suber seedlings were grown in two containers types: a shallow container (CCS-18) and a deep container (CCL-30). Seedlings were established in a degraded shrubland at three experimental sites in the Calderona mountain range of Castellón, Spain. A factorial design was combined based on container type (CCS-18 and CCL-30), shrubland management (undisturbed shrubland and cleared shrubland in strips) and tree shelters (vegetable fibre tree shelters and no tree shelters). After 2 years of monitoring, the outplanting results indicated that using: (i) a deep container produced a longer taproot, but did not favour better survival or better field performance of seedlings; (ii) tree shelters improved the microweather conditions around seedlings, particularly by reducing excess incoming solar radiation; (iii) cleared shrubland strips reduced competition for soil water by favouring a higher water potential, better maximum photochemical PSII efficiency and higher survival rates for the seedlings established into cleared sites. The results indicate that the cleared shrubland treatment effects overlap the effects of using deep containers and tree shelters. This, in turn, reveals that shrubland clearing is the most suitable technique for favouring the introduction of a resprouter species like Q. suber into ecosystems characterized by predominantly degraded shrublands.

Keywords: Deep Container, Tree Shelters, Cleared Shrubland, Ecological Restoration

iForest 13 (2): 114-123 (2020) - doi: 10.3832/ifor3095-013
https://iforest.sisef.org/contents/?id=ifor3095-013

Research Articles: Conservation of Betula oycoviensis, an endangered rare taxon, using vegetative propagation methods

Vítámvás J, Kuneš I, Viehmannová I, Linda R, Baláš M — 2020-03-23

Vítámvás J, Kuneš I, Viehmannová I, Linda R, Baláš M

CONSERVATION OF BETULA OYCOVIENSIS, AN ENDANGERED RARE TAXON, USING VEGETATIVE PROPAGATION METHODS

Abstract: Ojcow birch (Betula oycoviensis Besser) is a rare Central European tree taxon, micro-populations of which are found in only several localities. With a view to maintaining the B. oycoviensis gene pool, this study tested the species’ potential for micropropagation, grafting, and propagation by cuttings. Plant material for vegetative propagation was collected from ten genotypes in the Czech Republic. In vitro culture was established from axillary buds surfaces sterilized with 0.1% HgCl2 and cultivated on woody plant (WP) medium supplemented with 1 mg l-1 6-benzylaminopurine (BAP). Two genotypes of the species were successfully multiplied by in vitro propagation using WP medium supplemented with 0-2 mg l-1 BAP. The BAP concentration of 1 mg l-1 proved to be optimal, yielding 2.5 new shoots per explant in genotype 516 and 3.5 shoots per explant in genotype 545. The shoots were rooted on half-strength Murashige and Skoog (MS) medium supplemented with various concentrations of α-naphthylacetic acid (NAA) and indole-3-butyric acid (IBA). The highest rooting percentages (72.5% and 77.5% for genotypes 516 and 545, respectively) were achieved on the medium with the combination of both auxins at concentrations of 0.3 mg l-1. The rooted plants were transferred ex vitro in substrate composed of sand, peat, and perlite (1:1:1) and acclimated in the greenhouse. After 4 weeks, more than 90% of plants survived. Grafting was carried out in spring using Betula pendula as rootstock. The efficiency of this technique ranged from 0% to 50% across genotypes, and 4 out of 10 genotypes were successfully propagated by grafting. The cuttings were treated with commercial root stimulators Stimulax I and Stimulator AS-1, planted in a mixture of peat and sand (1:1) in the greenhouse, and watered regularly. This technique resulted in 0% rooting, however, and no cutting survived until the end of the vegetation period. The results of this study show that protocols for in vitro propagation and grafting can be employed for effective mass propagation of B. oycoviensis, although these processes show genotype-dependent responses.

Keywords: Betula, Cutting, Grafting, In vitro Propagation, Rooting

iForest 13 (2): 107-113 (2020) - doi: 10.3832/ifor3243-013
https://iforest.sisef.org/contents/?id=ifor3243-013

Research Articles: Runoff reconstruction and climatic influence with tree rings, in the Mayo river basin, Sonora, Mexico

Martínez-Sifuentes AR, Villanueva-Díaz J, Estrada-Ávalos J — 2020-03-11

Martínez-Sifuentes AR, Villanueva-Díaz J, Estrada-Ávalos J

RUNOFF RECONSTRUCTION AND CLIMATIC INFLUENCE WITH TREE RINGS, IN THE MAYO RIVER BASIN, SONORA, MEXICO

Abstract: Dendrochronological series are reliable sources of information to analyze past hydrological and climatological variation that provides useful information for the management of water resources within basins. We analyzed dendrochronological series obtained from the upper Mayo River Basin using principal components analysis to determine a common climatic signal. Although the complete series extended for over 350 years, the representative period common to all series was from 1750 to 2014 (265 years) with an expressed population signal of over 0.85. Climate data (precipitation and temperature) were collected from the North American Land Data Assimilation System 2 model of the Land Data Assimilation System and hydrometrics records were obtained from the National Commission of Water in Mexico. The results of the response function showed an association of mean monthly temperature with the ring width series for the months of December of the previous year, May and October of the year of growth, and seasonally from January to July (r = -0.75, n = 36, p < 0.05). A significant response to rainfall of earlywood growth was observed for June, November, and December of the previous year, January and February of the growth year, and seasonally, from October of previous year to May of the current growth year (r = 0.70, n = 35, p < 0.05). Significant association also was found between earlywood and the accumulated runoff from October of the previous year to May of the growth year, which was used for reconstruction of the runoff flow between 1750 and 2014, which showed evidence of decadal drought. Significant correlation was found between the reconstructed runoff series, and the Southern Oscillation index (r = -0.42, n = 228, p < 0.05), but not significant with the Pacific Decadal Oscillation index (r = 0.16, n = 115, p < 0.05). We also observed significant (p < 0.05) associations with the drought indices Palmer Drought Severity Index and Standardized Precipitation Evapotranspiration Index (r = 0.56, r = 0.41, respectively). Our study demonstrated the potential of assimilated data for dendroclimatic reconstructions and the feasibility of generating hydroclimatic information of extreme events that have not been recorded in the available climatic and hydrological instrumental records.

Keywords: Assimilated Data, Dendrohydrology, ENSO, Pinus arizonica

iForest 13 (2): 98-106 (2020) - doi: 10.3832/ifor3190-013
https://iforest.sisef.org/contents/?id=ifor3190-013

Short Communications: The importance of tree species and size for the epiphytic bromeliad Fascicularia bicolor in a South-American temperate rainforest (Chile)

2020-03-10

Ortega-Solís G, Díaz I, Mellado-Mansilla D, Moreno-González R, Godoy J, Samaniego H

THE IMPORTANCE OF TREE SPECIES AND SIZE FOR THE EPIPHYTIC BROMELIAD FASCICULARIA BICOLOR IN A SOUTH-AMERICAN TEMPERATE RAINFOREST (CHILE)

Abstract: Bromeliads are a numerous family of vascular epiphytes, though only one epiphytic species inhabits South-American temperate rainforests: the endemic Fascicularia bicolor. This bromeliad is an important driver of canopy biodiversity, but attributes of its hosts are mostly unknown. Here we report (i) the tree species colonized by F. bicolor, (ii) the relationship between tree size and presence of F. bicolor and (iii) the relation between tree size and the number of mats of F. bicolor inhabiting each colonized tree. We sampled 231 trees in seven forest plots recording their species, diameter, heights, and the number of F. bicolor mats growing on them. The dataset was analyzed with a zero-inflated model to relate host tree attributes with F. bicolor occurrence and abundance in a single statistical approach. The occurrence and abundance of F. bicolor depend on host-species identity and diameter. F. bicolor colonization in slow-growing trees started at smaller DBH than that required for other tree species. Nonetheless, the overall occurrence of F. bicolor relies on large trees above 50 cm DBH for most host species. The number of mats occurring on each colonized tree depends on the interaction between tree height and species suggesting the importance of space available for colonization along the tree-trunk, and differential effects due to species’ traits. Currently, large trees and old-growth forests are scarce within the distribution range of F. bicolor, which could seriously affect the long-term conservation of this endemic epiphyte, along with the canopy properties and species associated with it.

Keywords: Forest Canopy, Epiphytes, Bromeliads, South American Temperate Forests

iForest 13 (2): 92-97 (2020) - doi: 10.3832/ifor2710-013
https://iforest.sisef.org/contents/?id=ifor2710-013

Research Articles: Oak often needs to be promoted in mixed beech-oak stands - the structural processes behind competition and silvicultural management in mixed stands of European beech and sessile oak

Maleki K, Zeller L, Pretzsch H — 2020-03-01

Maleki K, Zeller L, Pretzsch H

OAK OFTEN NEEDS TO BE PROMOTED IN MIXED BEECH-OAK STANDS - THE STRUCTURAL PROCESSES BEHIND COMPETITION AND SILVICULTURAL MANAGEMENT IN MIXED STANDS OF EUROPEAN BEECH AND SESSILE OAK

Abstract: Forest ecosystems nowadays provide multiple ecosystem goods and services at a time and throughout all development phases. Species mixing is considered an effective measure to gain benefits beyond purely additive effects. However, the complex structural processes behind interspecific competition and temporal and spatial facilitative effects through mixing are still far from being understood and predictable. In particular the mixture of European beech (Fagus sylvatica L.) and sessile oak (Quercus petraea [Matt.] Liebl.) is gaining even more importance due to the fact that forests from these species are considered more tolerant to climatic effects and are expected to expand their natural range to the north due to global warming. The 30 long-term experimental plots analysed in this study reveal the structural processes in mixed beech-oak stands based on data at the tree and stand level. Using spatial and non-spatial structural indices, we can show an increasing dominance of beech over oak in unmanaged stands and the effectiveness of thinning operations to support oak. Those processes are representative for other light-demanding tree species in mixtures with shade-tolerant species. Improving the knowledge on the structural processes in mixed-species stands is particularly relevant when trying to modify forest structure in order to adapt forest management to shifting environmental conditions and the increasing demand for ecosystem services.

Keywords: Ecosystem Services and Functions, Facilitation and Competition, Mixing Regulation, Silvicultural Prescriptions, Spatial Distribution, Stand Development, Structural Complexity, Thinning

iForest 13 (2): 80-88 (2020) - doi: 10.3832/ifor3172-013
https://iforest.sisef.org/contents/?id=ifor3172-013

Short Communications: Preliminary indications for diverging heat and drought sensitivities in Norway spruce and Scots pine in Central Europe

Kunert N — 2020-03-01

Kunert N

PRELIMINARY INDICATIONS FOR DIVERGING HEAT AND DROUGHT SENSITIVITIES IN NORWAY SPRUCE AND SCOTS PINE IN CENTRAL EUROPE

Abstract: Massive and increasing tree mortality is currently observed in the two conifer species Norway spruce and Scots pine in Central Europe. Consecutive dry years are made responsible for this phenomenon. Leaf trait measurements, in specific leaf osmotic potential (πosm) and leaf water potential at turgor loss (πtlp), indicate that the underlying mechanisms for tree mortality are most likely different between the two species. πtlp of spruce was highly negative, revealing a potentially high drought tolerance of the species. πtlp of Scots pine was less negative, suggesting a higher susceptibility to drought stress. I conclude that the mortality of Norway spruce might be caused by rising temperatures and that the summer temperatures in the past years were beyond the species thermal tolerance threshold. Overall, I want to highlight and enhance the discussion that the search for suitable species for a climate change adapted forest should go in both directions, i.e., species should be chosen to make the forest fit for both increasing drought and heat stress.

Keywords: Tree Mortality, Water Stress, Heat Stress, Physiological Limitations, Conifers

iForest 13 (2): 89-91 (2020) - doi: 10.3832/ifor3216-012
https://iforest.sisef.org/contents/?id=ifor3216-012

Research Articles: The effectiveness of short-term microwave irradiation on the process of seed extraction from Scots pine cones (Pinus sylvestris L.)

Aniszewska M, Zychowicz W, Gendek A — 2020-02-13

Aniszewska M, Zychowicz W, Gendek A

THE EFFECTIVENESS OF SHORT-TERM MICROWAVE IRRADIATION ON THE PROCESS OF SEED EXTRACTION FROM SCOTS PINE CONES (PINUS SYLVESTRIS L.)

Abstract: The influence of short-term microwave irradiation on the process of seed extraction from Scots pine cones was investigated in this study. Cones from the Brzesko Forest District (near Kraków, southern Poland) were collected in 2015. The size and changes in the mass of cones during the process of seed extraction, as well as the relations between these parameters, were analyzed. Changes in water content and drying rate of cones were modeled using suitable mathematical equations. The thermal balance of the whole process of seeds extraction was calculated, and the heat necessary to extract the seeds was determined. Cones were initially exposed to 2.45 GHz microwaves with a power of 800 W for either 5 or 15 seconds. Subsequently, cones were placed in a circulating air oven and seeds extracted under convective drying at a constant temperature of 50 ± 0.1 °C. We found that seeds from cones subjected to 15-seconds microwave radiation were dramatically damaged, while no significant difference were found in germination and quality of seeds between cones subjected to the 5-seconds microwave pre-treatment and control cones, both yielding first-class quality seeds (mean germination capacity > 90%). The results of this study could help developing microwave-dryer control algorithms to support the automated process of cone seed extraction in large-capacity extraction plants.

Keywords: Seed Extraction Heat, Drying Process, Moisture Content, Seed Viability

iForest 13 (1): 73-79 (2020) - doi: 10.3832/ifor3089-012
https://iforest.sisef.org/contents/?id=ifor3089-012

Research Articles: Soil stoichiometry modulates effects of shrub encroachment on soil carbon concentration and stock in a subalpine grassland

Ding L, Wang P, Zhang W, Zhang Y, Li S, Wei X, Chen X, Zhang Y, Yang F — 2020-02-07

Ding L, Wang P, Zhang W, Zhang Y, Li S, Wei X, Chen X, Zhang Y, Yang F

SOIL STOICHIOMETRY MODULATES EFFECTS OF SHRUB ENCROACHMENT ON SOIL CARBON CONCENTRATION AND STOCK IN A SUBALPINE GRASSLAND

Abstract: There is little information available on the mediating effects of soil nutrient stoichiometry and enzyme stoichiometry on soil carbon (C) during shrub encroachment and their contributions to changes in soil C. Here, we characterized the concentration and stock of soil organic carbon (SOC), inorganic carbon (SIC) and total carbon (STC) along the shrub encroachment sequence (SES). We constructed linkages between soil C and SES with soil nutrient stoichiometric ratios and C-, nitrogen- and phosphorus-acquiring enzyme stoichiometry ratios using structural equation modeling (SEM), and disentangled the contributions of the soil nutrient stoichiometric ratios and enzyme stoichiometric ratios to shaping SOC and SIC using redundancy analysis (RDA) and SEM. Results revealed that the increases in STC stock derived from the increases in both the SOC stock and the SIC stock. Soil stoichiometric ratios played a mediating role in structuring soil C over SES, the mediating pattern depended on soil stoichiometry types (nutrient stoichiometry or enzyme stoichiometry) and soil C types (SOC, SIC or STC). Soil nutrient stoichiometric ratios contributed more than soil enzyme stoichiometric ratios to the variation in SOC and STC, while the contributions of these two types of soil stoichiometric ratios to the variation in SIC changed with soil stoichiometry types. Soil nutrient stoichiometry had positive or negative or threshold effects on soil C, but soil enzyme stoichiometry had monotonously increasing effects on soil C. This study showed that the soil stoichiometry had modulatory effects on soil C during shrub encroachment in the subalpine grassland, China.

Keywords: Encroachment Succession, Soil Organic Carbon, Soil Inorganic Carbon, Soil Total Carbon, Nutrient Stoichiometry, Enzyme Stoichiometry, Mediating Effect, Relative Importance

iForest 13 (1): 65-72 (2020) - doi: 10.3832/ifor3091-012
https://iforest.sisef.org/contents/?id=ifor3091-012

Research Articles: Artificial intelligence associated with satellite data in predicting energy potential in the Brazilian savanna woodland area

2020-02-05

Carrijo JVN, Miguel EP, Teixeira Do Vale A, Matricardi EAT, Monteiro TC, Rezende AV, Inkotte J

ARTIFICIAL INTELLIGENCE ASSOCIATED WITH SATELLITE DATA IN PREDICTING ENERGY POTENTIAL IN THE BRAZILIAN SAVANNA WOODLAND AREA

Abstract: The use of artificial intelligence to generate information of the savanna’s energy capacity may support sustainable management of those areas. We assessed the efficacy of artificial neural networks (ANNs) combined with satellite data to estimate the energy potential (Pe) for cerradão, a dense savannah-like vegetation type in Brazil. We conducted a forest inventory for measuring dendrometric variables and sampling woody materials and barks in a cerradão area in the state of Tocantins, Brazil. The Pe of cerradão biomass was estimated based on the observed higher calorific power and drier biomass values. Six vegetation indices were retrieved from a RapidEye image and tested for correlation to choose the optimum vegetation index for biomass modeling. The basal area and the Normalized Difference Vegetation Index were used as predictors in the Pe modeling. We estimated an average of 19.234 ± 0.411 GJ ton-1 and 19.878 ± 1.090 GJ ton-1 for higher heating values of the wood species and barks, respectively, and an average Pe of 1022.660 GJ ha-1. The best ANN showed an error of 11.3% by using a structure of two, eight, and one neurons in the input layer, in the hidden layer, and in the output layer, respectively, as well as activation functions of the tangential and sigmoidal types. The validation tests showed no significant difference between the observed and ANN-predicted values. Based on our results, we concluded that Pe can be efficiently predicted by combining ANNs and remotely sensed data, which ultimately is a promising tool for forest sustainable management of the cerrado ecosystems.

Keywords: Artificial Neural Networks, Cerrado, Higher Heating Value, Biomass, Modelling, Forestry

iForest 13 (1): 48-55 (2020) - doi: 10.3832/ifor3209-012
https://iforest.sisef.org/contents/?id=ifor3209-012

Research Articles: Growth dynamics of the Norway spruce and silver fir understory in continuous cover forestry

2020-02-05

Vencurik J, Kucbel S, Saniga M, Jaloviar P, Sedmáková D, Pittner J, Parobeková Z, Bosela M

GROWTH DYNAMICS OF THE NORWAY SPRUCE AND SILVER FIR UNDERSTORY IN CONTINUOUS COVER FORESTRY

Abstract: The conversion to uneven-aged, mixed-species stands represents one possible way to mitigate the consequences of disturbances in Norway spruce forests in Central Europe. A better understanding of the establishment and growth dynamics of the understory can contribute to a more effective conversion process. Here we investigate the structure of understory, light climate and growth of natural regeneration of Norway spruce and silver fir in two forest stands undergoing conversion to continuous cover forestry. Stand-wise forest inventory was conducted in 1993 and 2013. The natural regeneration was surveyed, and the light conditions and inter-tree competition were quantified in 51 sample plots established across the stands in 2013. Our results suggest that the diffuse radiation strongly affects the height growth of fir and spruce natural regeneration. We do not confirm the effect of local sapling density on the regeneration dynamics. The results further show that fir trees grow faster than spruce under less intensity of diffuse light. Most of the spruce and fir trees reached the upper limit of the lower overstory (DBH 12 cm) at approximately 50 years of age. Thus, more substantial reductions in stand density can lead to a well-differentiated structure in less than five decades. To control the prospective representation of spruce and fir in mixed-species forests undergoing the conversion, managing of light conditions is crucial.

Keywords: Conversion to Selection Forest, Natural Regeneration, Height Growth, Diffuse Light

iForest 13 (1): 56-64 (2020) - doi: 10.3832/ifor3183-012
https://iforest.sisef.org/contents/?id=ifor3183-012

Technical Reports: Conservation and use of elm genetic resources in France: results and perspectives

2020-02-03

Collin E, Rondouin M, Joyeau C, Matz S, Raimbault P, Harvengt L, Bilger I, Guibert M

CONSERVATION AND USE OF ELM GENETIC RESOURCES IN FRANCE: RESULTS AND PERSPECTIVES

Abstract: Launched in 1987, the French National Programme for the Conservation of Native Elm Genetic Resources focused on the ex situ conservation of clones of adult field elms (Ulmus minor Mill.) survivors of the Dutch elm disease (DED) pandemic. It was later expanded to include the in situ dynamic conservation of populations of European white elm (U. laevis Pall.) and wych elm (U. glabra Huds.). The national collection contains 441 clones, partly characterized and evaluated in a European project. The pathological tests and experimental plantations did not reveal clones truly resistant to DED but provided material for the restoration of hedgerows. Two conservation units of white elm and one of wych elm were selected, enriching the pan-European EUFORGEN network for dynamic conservation of forest genetic resources. This programme provides feedback on genetic conservation strategies for forest trees in a health crisis. New partners are invited to make use of the scientific potential of the clone bank and experimental plots.

Keywords: Ulmus, Genetic Resources, Ex Situ Conservation, In Situ Conservation, France

iForest 13 (1): 41-47 (2020) - doi: 10.3832/ifor3065-013
https://iforest.sisef.org/contents/?id=ifor3065-013

Research Articles: Outplanting performance of three provenances of Quillaja saponaria Mol. established in a Mediterranean drought-prone site and grown in different container size

Espinoza SE, Yañez MA, Magni CR, Santelices RE, Cabrera AM — 2020-01-21

Espinoza SE, Yañez MA, Magni CR, Santelices RE, Cabrera AM

OUTPLANTING PERFORMANCE OF THREE PROVENANCES OF QUILLAJA SAPONARIA MOL. ESTABLISHED IN A MEDITERRANEAN DROUGHT-PRONE SITE AND GROWN IN DIFFERENT CONTAINER SIZE

Abstract: In degraded environments with restricted seed availability, like those burned by wildfires in central Chile during 2017, the use of plant material from outside its area of origin for restoration purposes needs to be accurately investigated. We assessed the early development of three Chilean provenances of Quillaja saponaria grown in different container sizes (140 vs. 280 mL) in the nursery and then outplanted in a common field trial at a site severely affected by fire under Mediterranean-type climate. We analyzed growth, biomass, and leaf-level physiological traits. In the nursery, there was a significant provenance by container type interaction for the biomass traits (P < 0.05). Seedlings from the Maule provenance cultivated in larger containers had the highest biomass, while the lowest biomass was observed for the Metropolitan provenance cultivated in small containers. Two years after outplanting, the provenance by container size interaction was significant for stomatal conductance and chlorophyll density. Seedlings from the Metropolitan provenance cultivated in larger containers exhibited a higher stomatal conductance, while those from the Maule provenance cultivated in small containers exhibited the highest chlorophyll density. Seedling height showed significant variation for provenance and container size. The tallest seedlings were those grown in larger containers from the Maule provenance; however, no differences in survival and height increment were found. Gas exchange parameters differed among provenances, the Metropolitan provenance had a low performance and the opposite was found for the Biobío and Maule provenances. This study demonstrated that different provenances of Q. saponaria have stable performances in a Mediterranean site, which support their use for restoration purposes outside their home area with no detrimental effects on outplanting performance.

Keywords: Restoration, Quillay, Dry Site, Water Stress, Pot Size, Seed Origin

iForest 13 (1): 33-40 (2020) - doi: 10.3832/ifor3142-012
https://iforest.sisef.org/contents/?id=ifor3142-012

Research Articles: A physiological approach for pre-selection of Eucalyptus clones resistant to drought

Müller C, Hodecker BER, De Barros NF, Merchant A — 2020-01-15

Müller C, Hodecker BER, De Barros NF, Merchant A

A PHYSIOLOGICAL APPROACH FOR PRE-SELECTION OF EUCALYPTUS CLONES RESISTANT TO DROUGHT

Abstract: Water deficit is one of the abiotic stresses that most affects the growth and survival of Eucalyptus. Mechanisms used to tolerate water-limited environments influence the distribution of Eucalyptus species in their natural environment. Here, we take a physiological approach to pre-screen Eucalyptus plants for tolerance to drought. Ten different clones of E. urophylla and E. grandis × E. urophylla that are known to show contrasting responses to water deficit under field conditions, were grown in Clark’s nutrient solution (WW, well-watered) and with polyethylene glycol (-1.0 MPa) to simulate water deficit (WD). Clones responded differently to drought with differentiated photosynthetic limitations in drought-treated clones. Photosynthetic rates, stomatal conductance, transpiration and internal CO2 concentrations were reduced in all genotypes under stress conditions. Clone i144 had a smaller reduction in the evaluated physiological traits, also showing increased root growth in WD-treated plants. Clones 3367 and i224, thought to be moderately tolerant, also followed these patterns. Clones gg157, 1568 and 1641, all of which are moderately sensitive under field conditions, reduced most of the physiological characters evaluated. However, clone gg157 demonstrated increased root system growth, even during short periods of water stress. Clones i042 and i182 were deemed drought-susceptible, with large reductions in photosynthesis and growth, despite showing a high increase in abscisic acid content presumably as a defense mechanism. Interaction between A (photosyntetic rate), E (transpiration rate), ETR/A (electrons transport rate/photosynthetic rate) and SDM/ RDM (shoot dry matter/root dry matter) demonstrated the most significant differences between WD-treated clones and offer great potential for use as selection criterion for water deficit-tolerant genotypes.

Keywords: Clonal Variability, Genotypes, Cluster Analysis, Water Stress

iForest 13 (1): 16-23 (2020) - doi: 10.3832/ifor3185-012
https://iforest.sisef.org/contents/?id=ifor3185-012

Research Articles: Variation of major elements and heavy metals occurrence in hybrid aspen (Populus tremuloides Michx. × P. tremula L.) tree rings in marginal land

2020-01-15

Bardule A, Bertins M, Busa L, Lazdina D, Viksna A, Tvrdonova M, Kanicky V, Vaculovic T

VARIATION OF MAJOR ELEMENTS AND HEAVY METALS OCCURRENCE IN HYBRID ASPEN (POPULUS TREMULOIDES MICHX. × P. TREMULA L.) TREE RINGS IN MARGINAL LAND

Abstract: Fast growing tree species such as Populus spp. in short rotation woody crop (SRWC) systems could be an environmentally friendly and cost-effective approach to ensure sustainable biomass production and mitigate the negative impacts on the environment caused by more intensive management aimed to promote additional biomass increment. Knowledge on variation of major biologically important elements’ and toxic heavy metals’ occurrence in fertilised hybrid aspen tree rings in marginal land may have important and relevant implications for the management practice and evaluation of element fluxes in SRWC ecosystems. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to determine the relative amount of major elements (K, Ca, Mg, P) and heavy metals (Cd, Hg, Pb) in stem wood plane on straight line trajectory starting from pith to bark with measurement step 0.1 mm. While inductively coupled plasma mass spectrometry (ICP-MS) was used to determine average content of the mentioned elements in mechanically separated tree rings to quantify data obtained using LA-ICP-MS method and expressed in relative units. Stem disc samples were collected from six year old hybrid aspen trees growing in marginal agricultural land in the central part of Latvia (hemi-boreal climate conditions) that were initially fertilised with biogas production residues, sewage sludge, and wood ash. We concluded that the content of analysed major elements and heavy metals in the hybrid aspen tree rings varied considerably not only within the analysed stem plane (across tree rings) of one sample tree, but also within one annual ring with significant differences between the content of major elements in earlywood and latewood. Nevertheless, the results of the content of major elements and heavy metals in hybrid aspen tree rings highlighted the significant impact of the initially used fertiliser (especially wood ash) on the average content of elements. Hybrid aspens can be considered bioindicators of both the management activities and general growing conditions even if soil pH is close to neutrality, suggesting a limited mobility of the heavy metals.

Keywords: Dendroanalyses, Hybrid Aspen, Tree Rings, Major Elements, Heavy Metals, LA-ICP-MS

iForest 13 (1): 24-32 (2020) - doi: 10.3832/ifor2869-012
https://iforest.sisef.org/contents/?id=ifor2869-012

Research Articles: Interactions between thinning and bear damage complicate restoration in coast redwood forests

O’Hara KL, Narayan L, Leonard LP — 2020-01-08

O’Hara KL, Narayan L, Leonard LP

INTERACTIONS BETWEEN THINNING AND BEAR DAMAGE COMPLICATE RESTORATION IN COAST REDWOOD FORESTS

Abstract: Silviculture was used to direct the development of young redwood stands toward old forest stand structures. Two variable-density thinning treatments and an unthinned control treatment were monitored for 10 years following treatment in young coast redwood (Sequoia sempervirens) stands in northern California, USA. The intent of these treatments was for forest restoration by accelerating the development of old forest features. The thinning treatments increased individual tree growth in both low and moderate density thinning treatments as compared to the control. The variable-density thinning also resulted in greater stand structural variability and was successful at increasing the relative proportion of redwood. Black bears (Ursus americanus) caused major damage to residual trees and showed a preference for more vigorous trees. Most of this damage occurred in the first four years after thinning. The confounding effects of thinning to favor larger trees and bear damage preferentially affecting more vigorous and large trees reduced the effectiveness of these treatments by eliminating the stems intended to form the future old forest structures. It also indicates forest managers need a conservative approach that leaves greater numbers of residual trees in redwood stands when bears are present. Thinning should leave sufficient trees to form the old forest structure plus ample allowances for bear-caused mortality. The long-term outcome of stand development in these thinned redwood forests is uncertain because of high rates of mortality in young trees.

Keywords: Sequoia sempervirens, Restoration, Variable-Density Thinning, Precommercial Thinning, Silviculture, Ursus americanus

iForest 13 (1): 1-8 (2020) - doi: 10.3832/ifor3135-012
https://iforest.sisef.org/contents/?id=ifor3135-012

Research Articles: Testing Hungarian oak (Quercus frainetto Ten.) provenances in Romania

Apostol EN, Stuparu E, Scarlatescu V, Budeanu M — 2020-01-08

Apostol EN, Stuparu E, Scarlatescu V, Budeanu M

TESTING HUNGARIAN OAK (QUERCUS FRAINETTO TEN.) PROVENANCES IN ROMANIA

Abstract: In this study ten Hungarian oak provenances from Southern Romania were tested in two comparative trials 10 years after planting. The diameter at breast height (dbh) and tree height (Th) were measured in family progenies and the survival rate was determined. In both trials, the local provenances (Bals and Seaca 2) revealed superior fitness in terms of growth and adaptability traits, confirming the recommendation of using local provenances with priority in afforestation activities. Based on the measured traits, families which ranked in the first ten positions at age 3 and age 10 years were identified in both trials. The analysis of variance revealed statistically significant differences in growth traits between provenances and families in both comparative trials. Duncan’s test for 5% transgression probability revealed different results for dbh and Th in terms of provenance homogeneity in the two test sites, with a superior homogeneity in the Aramadia trial for dbh and in the Bals trial for Th. Growth performances of the Hungarian oak provenances were significantly influenced by the experimental location and by the interactions between provenance, family and locality, suggesting that maximum precaution must be taken in the choice of forest reproductive materials to be planted in different environmental conditions. The family mean heritability (h2f) was significantly lower than the individual heritability (h2i), suggesting the possible adoption of an individual selection strategy in the next stage of the current breeding programme. The juvenile-adult correlations will be made at the age of 40 years and will take advantage of the results of this study to shorten the testing period for the selection of genetically improved material in Hungarian oak.

Keywords: Age-to-age Correlations, Breeding, Forest Steppe, Oaks’ Adaptability, Selection Strategy

iForest 13 (1): 9-15 (2020) - doi: 10.3832/ifor3108-012
https://iforest.sisef.org/contents/?id=ifor3108-012

Research Articles: Facilitating objective forest land use decisions by site classification and tree growth modeling: a case study from Vietnam

Cuong ND, Volker M, Köhl M — 2019-12-17

Cuong ND, Volker M, Köhl M

FACILITATING OBJECTIVE FOREST LAND USE DECISIONS BY SITE CLASSIFICATION AND TREE GROWTH MODELING: A CASE STUDY FROM VIETNAM

Abstract: Onsite information pertaining to forest growth potential is a significant prerequisite for selecting suitable forest plantation locations and safeguards sustainable timber production and income generation. In the scope of forest landscape restoration, the selection of the most suitable sites for reforestation remains a major issue. The current study introduces an operational, objective, and straightforward methodology for the identification and prioritization of sites that are suitable for forest plantations. The methodology is based on an approach that combines land use suitability assessment with site-specific growth and yield predictions. The land use suitability assessment is based on a methodological framework presented by the Food and Agriculture Organization (FAO). In a study area in Vietnam four different suitability classes are defined for the species Acacia mangium (A. mangium). Field assessments in existing A. mangium plantations were utilized to develop yield models. Among the Korf, Gompertz, and Chapman-Richards growth equations Korf performed the best for all suitability classes. Prioritization of sites is realized by the analytical hierarchy process (AHP). Our study offers a pragmatic approach for selecting the most suitable sites for large-scale forest restoration activities. Integrating growth and yield predictions supports reforestation practices and promotes sustainable timber production.

Keywords: Acacia mangium, Suitability, Analytical Hierarchy Process, Volume Growth, Vietnam

iForest 12 (6): 542-550 (2019) - doi: 10.3832/ifor2945-012
https://iforest.sisef.org/contents/?id=ifor2945-012

Research Articles: Relationships between leaf physiognomy and sensitivity of photosynthetic processes to freezing for subtropical evergreen woody plants

Cheng D, Zhang Z, Zhou S, Peng Y, Zhang L — 2019-12-17

Cheng D, Zhang Z, Zhou S, Peng Y, Zhang L

RELATIONSHIPS BETWEEN LEAF PHYSIOGNOMY AND SENSITIVITY OF PHOTOSYNTHETIC PROCESSES TO FREEZING FOR SUBTROPICAL EVERGREEN WOODY PLANTS

Abstract: Subtropical and tropical species in high altitude suffer from low temperature more frequently than those from temperate regions. Chlorophyll fluorescence analysis can measure the primary photochemical processes of photosystem II (PSII) and help evaluate the sensitivity of evergreen woody plants to low temperature. Coupled with leaf physiognomy, it has allowed to examine the potential thermal regulation of evergreens in response to extreme coldness. The leaf physiognomy (length, width, thickness and ratio of length/width) and chlorophyll a fluorescence (Fv/Fm, maximum potential photochemical efficiency of PSII; NPQ, non-photochemical quenching of chlorophyll fluorescence; and Y(II), effective photochemical quantum yield of photosystem II) under natural freezing and recovery conditions of nine evergreen woody trees were measured to analyze their relationships. Results showed that the changes of Fv/Fm under freezing versus recovery had a positive relationship with leaf length and width, while a negative relationship with leaf thickness. Similar to leaf size, leaf shape also influenced the photoinhibition levels of evergreens by regulating the leaf boundary layer thickness. Leaves with an oval-like shape suffered less from freezing than leaves with a lanceolate-like shape. A relatively weaker relationship between NPQ and Y(II) was found at freezing than after recovery for species with larger and lanceolate-like leaves. Our findings are helpful to understand the adaptation strategy of evergreen woody species to extreme low temperature in subtropical areas and to provide guidance for the management of evergreen plants introduced in botanical gardens.

Keywords: Leaf Size, Leaf Shape, Chlorophyll a Fluorescence, Photoinhibition, Low Temperature Stress, Evergreens

iForest 12 (6): 551-557 (2019) - doi: 10.3832/ifor3196-012
https://iforest.sisef.org/contents/?id=ifor3196-012

Research Articles: Dust collection potential and air pollution tolerance indices in some young plant species in arid regions of Iran

2019-12-17

Javanmard Z, Kouchaksaraei Tabari M, Bahrami H, Hosseini SM, Sanavi SAMM, Struve D

DUST COLLECTION POTENTIAL AND AIR POLLUTION TOLERANCE INDICES IN SOME YOUNG PLANT SPECIES IN ARID REGIONS OF IRAN

Abstract: Dust is one of the main environmental challenges in most arid zone cities of Iran. Tree plantation and forest belts can provide a cost-effective and eco-friendly solution to mitigate dust pollution. Air pollution tolerance index (APTI) based on a combination of total chlorophyll (TChl), relative water content (RWC), ascorbic acid (AsA), and leaf pH is considered as one of the most important means for determining sensitive and tolerant plant species for greening. The present study aimed to evaluate the dust capturing efficiency and APTI of Fraxinus rotundifolia Mill., Morus alba L., Celtis caucasica Willd., and Melia azedarach L., four tree species commonly used in urban green areas of most cities in Iran. As a completely randomized design, 256 saplings were grown in four plastic sheets (64 saplings of four species in each chamber) and the dust was applied at concentrations of 0, 300, 750, and 1500 μg m-3 once a week for 70 days. The results revealed that dust accumulation was greatest in the 750 and 1500 μg m-3 treatment in the following order: M. alba > C. caucasica > F. rotundifolia > M. azedarach. In all species, pH, RWC, AsA, and TChl diminished with increasing dust concentration. A decline in APTI of 0 to 1500 μg m-3 was observed in all species. At 750 μg m-3, only M. alba was tolerant to dust and the other species were intermediate. At 1500 μg m-3, M. alba and M. azedarach showed to be intermediate while two other species were sensitive. The greatest relationship was found between APTI and RWC (R2= 0.85), followed by APTI and AsA (R2 = 0.82). Although C. caucasica showed a high capacity for dust accumulation at 1500 μg m-3, it was found to be sensitive and can, therefore, be used as a dust pollution bioindicator. F. rotundifolia and C. caucasica are not suitable for plantation in urban green spaces where dust concentration is 1500 μg m-3. M. alba appeared to be a tolerant species adaptable to arid urban environments with a potential for reducing dust levels by sinking its particles.

Keywords: APTI, Ascorbic Acid, Dust Pollution, Persian Lilac, White Mulberry

iForest 12 (6): 558-564 (2019) - doi: 10.3832/ifor3063-012
https://iforest.sisef.org/contents/?id=ifor3063-012

Research Articles: Effect of stand density on longitudinal variation of wood and bark growth in fast-growing Eucalyptus plantations

Ramalho FMG, Pimenta EM, Goulart CP, De Almeida MNF, Vidaurre GB, Hein PRG — 2019-12-12

Ramalho FMG, Pimenta EM, Goulart CP, De Almeida MNF, Vidaurre GB, Hein PRG

EFFECT OF STAND DENSITY ON LONGITUDINAL VARIATION OF WOOD AND BARK GROWTH IN FAST-GROWING EUCALYPTUS PLANTATIONS

Abstract: The influence of tree spacing on the wood/bark ratio is unknown in young fast-growing Eucalyptus trees. The objective of this study was to evaluate the effect of plant spacing on the wood and bark production along the Eucalyptus stem. Four genetic materials were planted in four spacings: 3×1 m, 3×2 m, 3×3 m and 3×4 m. Three 5-year-old trees from each clone and in each plant spacing were harvested. Cross-sectional discs (thickness: 30 mm) were cut from each tree along the stem (0%, 25%, 50%, 75% and 100% of the total tree height) and at 1.3 m above ground, totaling 288 disks (4 spacings × 4 clones × 3 replicates × 6 axial positions). The wood thickness was measured at six random and equidistant points around the perimeter using a gauge and means were calculated from each disc. Six cross diameters were measured for each debarked disc. After obtaining the averaged bark thickness and wood diameter, the bark content was calculated as the ratio between the surface area occupied by the bark and the total area of the stem in each level. In the narrowed plant spacing (3×1), the trees had a mean diameter of 7.4 cm, while at the spacing 3×4 the diameter of the trees was 91% higher (14.11 cm) at breast height. The increase in plant spacing from 3 to 12 m2 per tree resulted in an increase in bark thickness (56.7%) from 1.94 mm to 3.04 mm, but caused a reduction of bark content (16%) from 9.66% to 8.11%. Our findings show that trees grown under wider spacing tend to produce thicker bark. The bark thickness and the effect of plant spacing on the bark thickness decreased in the base-top direction. The correlation between bark thickness and wood diameter increases from 0.682 to 0.825 with the increase of spacing between trees. In contrast, the bark thickness to bark content correlation decrease from 0.735 to 0.15 with increased plant spacing. The stand density significantly affected the variation of the stem diameter, bark thickness and bark content of Eucalyptus plantations.

Keywords: Stand Density, Timber, Bark, Silvicultural Treatment, Forest Productivity

iForest 12 (6): 527-532 (2019) - doi: 10.3832/ifor3082-012
https://iforest.sisef.org/contents/?id=ifor3082-012

Research Articles: Estimating biomass and carbon sequestration of plantations around industrial areas using very high resolution stereo satellite imagery

Hosseini Z, Naghavi H, Latifi H, Bakhtiari Bakhtiarvand S — 2019-12-12

Hosseini Z, Naghavi H, Latifi H, Bakhtiari Bakhtiarvand S

ESTIMATING BIOMASS AND CARBON SEQUESTRATION OF PLANTATIONS AROUND INDUSTRIAL AREAS USING VERY HIGH RESOLUTION STEREO SATELLITE IMAGERY

Abstract: Plantations established in highly-pollutant industrial areas have a crucial role to absorb greenhouse gases, particularly CO2. A thorough monitoring of their aboveground biomass and carbon balance is essential to ensure their beneficial effects. This can be operationally supported by using a combination of field and multispectral stereo remote sensing data to provide surface height information with high resolution and wide coverage. We estimated the fresh and dry aboveground biomass and the carbon sequestration from pairs of Pléiades satellite imagery of 25-year-old monoculture plantations of Pinus eldarica Medw., Cupressus arizonica Greene, Morus alba L. and Robinia pseudoacacia L., around the Mobarakeh Steel Complex near the megacity Isfahan. This complex is the largest-scale of its kind in semi-arid Iran. Tree heights were derived from a Canopy height model (CHM) at plantation management unit level. Parsimonious regression models were developed, and the accuracy was assessed by the coefficient of determination, bias and root mean square errors (RMSEs) at plot level. This resulted in R2 of total biomass, dry biomass, carbon sequestration, tree height and tree count of 0.90, 0.90, 0.91, 0.89, and 0.88, respectively. Moreover, mixed bias (with lowest value of -0.12 m for tree height) and NRMSE% (with lowest value of 5.93 % for tree carbon sequestration) values were obtained. The results demonstrated that pairs of stereo imageries can be effectively used for predicting forest biomass and carbon sequestration across semi-arid plantations, hence enabling a continuous monitoring of vegetation established around pollutant industrial areas.

Keywords: Carbon Sequestration, Biomass, Plantation, Industrial Areas, VHR Stereo Images

iForest 12 (6): 533-541 (2019) - doi: 10.3832/ifor3155-012
https://iforest.sisef.org/contents/?id=ifor3155-012

Research Articles: Analysis of canopy temperature depression between tropical rainforest and rubber plantation in Southwest China

Tay Zar Myo S A, Zhang Y, Song QH, Deng Y, Fei X, Zhou R, Lin Y, Zhou L, Zhang P — 2019-12-09

Tay Zar Myo S A, Zhang Y, Song QH, Deng Y, Fei X, Zhou R, Lin Y, Zhou L, Zhang P

ANALYSIS OF CANOPY TEMPERATURE DEPRESSION BETWEEN TROPICAL RAINFOREST AND RUBBER PLANTATION IN SOUTHWEST CHINA

Abstract: Temperature change is an important environmental variable for global change sciences since it largely affects the physiology of plants in forest ecosystems. Canopy temperature depression (CTD) - the result of the deviation of the air temperature (Ta) from the plant canopy surface temperature (Tc) - varies depending on the meteorological and environmental conditions of the forests. Here, we evaluated the differences in CTD between a rubber plantation (RP) and a tropical rainforest (TR) in Xishuangbanna, southwestern China across the various time series of the period of 2011 to 2015. The mean maximum CTD values at the TR site and the RP site were 2.4°C and 0.6°C at diurnal level, 1.3°C and -0.5°C at monthly level, 0.6°C and -0.8°C at seasonal level and 5.6°C and 0.2°C at yearly time series level, respectively, while they were only significant (p < 0.01) in the diurnal time series. There was a significant (p < 0.01) negative linear relationship between CTD and global radiation (Q) in both sites at diurnal level and a significant (p < 0.05) negative linear relationship in the RP site at monthly time series level. A significant (p < 0.05) positive linear relationship between CTD and precipitation (P) at the RP site was found at diurnal level, as well as a significant (p < 0.01) positive linear relationship in the TR site at monthly time series level. The variation of CTD was critical for these two sites and largely depended on the amount of global radiation and the precipitation, while it will mainly affect the physiological variables. This study may prove useful for assessing the physiological response in terms of high temperature and drought conditions to regional and global change.

Keywords: Canopy Temperature Depression, Global Radiation, Precipitation, Tropical Rainforest, Rubber Plantation

iForest 12 (6): 518-526 (2019) - doi: 10.3832/ifor3101-012
https://iforest.sisef.org/contents/?id=ifor3101-012

Review Papers: Accuracy of determining specific parameters of the urban forest using remote sensing

Ciesielski M, Sterenczak K — 2019-12-02

Ciesielski M, Sterenczak K

ACCURACY OF DETERMINING SPECIFIC PARAMETERS OF THE URBAN FOREST USING REMOTE SENSING

Abstract: This paper reviews the current state of knowledge in the field of urban forest inventory and specific tree parameters derived by remote sensing. The paper discusses the possibilities and limitations of using remote sensing to determine the following characteristics of individual trees acquired during the inventory: position (coordinates), tree height, breast height diameter, tree crown parameters (crown span, height of tree crown basis, crown projection surface), health condition, and tree species. A total of 543 papers published in scientific databases (Scopus® and ScienceDirect®) from the year 2000 to December 2017 have been analyzed; 86 of them were used for the review. The most important outcomes are: (a) the integration of many datasets, in particular spectral data (aerial images and satellite imageries) and structural data (LIDAR), allows the most complex use of remote sensing data and helps to improve the accuracy of parameter estimations as well as the correct identification of tree species; (b) the highest precision of measurement is characteristic of TLS, while ALS data has the largest operating system; (c) remote sensing data applications are associated with a large number of sophisticated processing on very large datasets using often proprietary elaborations; (d) the use of remote sensing data makes it possible to determine the characteristics of urban vegetation at various levels of detail and at different scales.

Keywords: Urban Forestry, Remote Sensing, Green Inventory, Laser Scanning, Hyperspectral Imaging, Satellite Imaging

iForest 12 (6): 498-510 (2019) - doi: 10.3832/ifor3024-012
https://iforest.sisef.org/contents/?id=ifor3024-012

Research Articles: Impacts of Norway spruce (Picea abies L., H. Karst.) stands on soil in continental Croatia

Perković I, Pernar N, Roje V, Bakšić D, Baneković M — 2019-12-02

Perković I, Pernar N, Roje V, Bakšić D, Baneković M

IMPACTS OF NORWAY SPRUCE (PICEA ABIES L., H. KARST.) STANDS ON SOIL IN CONTINENTAL CROATIA

Abstract: A quantitative analysis of pedo-physiological indicators aimed at determining changes in the soil attributable to the effects of spruce plantations was done. The study was conducted at eight sites in central and north-western Croatia where spruce plantations were planted in the late 20th century. At each site, a pedological profile was opened within the spruce plantation and the endo-morphological parameters of the soil were determined. Composite soil samples from two depths (0-10 cm and 10-20 cm) and from the forest floor were taken in the spruce plantation and compared with samples taken at plots covered by natural vegetation (natural stands) located in the surroundings. The following pedo-physiographic indicators were measured on the collected soil samples: quantity of forest floor, particle size distribution of soil, pH values in H2O and in CaCl2 aqueous solution (concentration 0.01 mol dm-3), content of Corg, content of Ntot and content of bioavailable nutrients (using the Mehlich III method). The results showed that the forest floor had a higher mass in the spruce plantations than in natural stands. The mineral soil showed clear trends of influence of the spruce plantations on soil in terms of reduced pH values. Most plots in the spruce plantations showed a lower nitrogen content in the soil, a higher C/N ratio and lower content of bioavailable phosphorus. This study provides an insight into the amelioration effects of spruce plantations on soil, and represent a reliable basis for decision-making in planning specific interventions in terrestrial ecosystems, such as the establishment of new forest plantations.

Keywords: Spruce Plantation, Forest Soil, Chemical Properties of Soil, Forest Floor

iForest 12 (6): 511-517 (2019) - doi: 10.3832/ifor3023-012
https://iforest.sisef.org/contents/?id=ifor3023-012

Editorials: Present challenges to global forests and the role of IUFRO

Parrotta JA — 2019-11-02

Parrotta JA

PRESENT CHALLENGES TO GLOBAL FORESTS AND THE ROLE OF IUFRO

Abstract: The new IUFRO President 2019-2024 Dr. John Parrotta, US Forest Service, summarizes his vision of the present challenges to global forests and the role of the International Union of Forest Research Organizations (IUFRO). This paper is drawn from his acceptance speech at the XXV IUFRO World Congress held in Curitiba, Brazil, on 29 Sept - 5 Oct 2019.

Keywords: IUFRO, Global Forests, Forest Challenges

iForest 12 (6): 488-490 (2019) - doi: 10.3832/ifor0066-012
https://iforest.sisef.org/contents/?id=ifor0066-012

Research Articles: Role of serotiny on Pinus pinaster Aiton germination and its relation to mother plant age and fire severity

Cruz O, García-Duro J, Casal M, Reyes O — 2019-11-02

Cruz O, García-Duro J, Casal M, Reyes O

ROLE OF SEROTINY ON PINUS PINASTER AITON GERMINATION AND ITS RELATION TO MOTHER PLANT AGE AND FIRE SEVERITY

Abstract: Serotiny degree may hypothetically depend on mother plant age and fire severity, and fire severity can strongly affect the regeneration of Pinus pinaster Aiton, which is an obligate seeder species with aerial seed banks stocked in cones showing a certain degree of serotiny. The main objective of this study was to evaluate the effect of serotiny and mother plant age on seed germination of P. pinaster in relation to fire severity. For this purpose, cones were collected in two stands from mother trees of different ages. Serotinous cones were opened in oven at increasing temperatures to determine the number of seeds released. The length of cones and the number and weight of seeds were measured. Seeds from both classes of mother plant age were subjected to 34 different treatments simulating different fire severity levels, and their germination was recorded. The results showed that serotiny was significantly higher in cones from young mother trees. Seed germination in the control groups from serotinous cones was always higher than that from non-serotinous cones without thermal shock. Fire severity decreased seed germination as fire severity increases in both mother age classes. Mother plant age was related to the serotiny level, which was higher in young than in old trees, suggesting a strong selection in the population due to a recent fire.

Keywords: Fire Severity, Germination, Mother Plant Age, Pinus pinaster, Plantation Management, Serotiny

iForest 12 (6): 491-497 (2019) - doi: 10.3832/ifor2968-012
https://iforest.sisef.org/contents/?id=ifor2968-012

Research Articles: Bioactivity of ethanol extracts from Eucalyptus bosistoana F. Muell. heartwood

Mishra G, Garrill A, Altaner CM — 2019-10-14

Mishra G, Garrill A, Altaner CM

BIOACTIVITY OF ETHANOL EXTRACTS FROM EUCALYPTUS BOSISTOANA F. MUELL. HEARTWOOD

Abstract: Variability in bioactivity and chemical composition of Eucalyptus bosistoana F. Muell. heartwood extracts between individual trees from two different sites were investigated. Combining the results of fungal assays and quantitative gas chromatography (GC) of the extracts allowed the investigation of bioactive compounds. The bioactivity of extracts was assessed against white rot (Trametes versicolor [L.] Lloyd) and brown rot (Coniophora cerebella Pers.). Ethanol extracts from E. bosistoana heartwood were less effective on the white rot than against the brown rot. Variability in the bioactivity of extracts against the two fungi was observed between the trees. A site effect in the bioactivity was found for the white rot but not the brown rot. Bioactivity of the extracts against the white rot was not correlated to that against the brown rot. The absence of a relationship between of effects of the extracts on the relative growth rates of the white rot and the brown rot indicated that the two fungi were affected by different compounds. Thirty two compounds were quantified in E. bosistoana ethanol extracts by GC, of which six (benzoic acid, hexadecanoic acid, 1,5-dihdroxy-12-methoxy-3,3-dimethyl-3,4-dihydro-1H-anthra[2,3-c]pyran-6,11-dione, octadecanoic acid, polyphenol and beta-sitosterol) were identified. Significant variability in eight compounds was found between the two sites. Multivariate (PLSR) analysis identified compounds at the retention times 10.2 and 11.5 min (hexadecanoic acid) to be most related to the bioactivity of the E. bosistoana heartwood extracts against white rot and brown rot.

Keywords: Brown Rot, Extractives, Fungal Assays, Gas Chromatography, Heartwood, White Rot

iForest 12 (5): 467-473 (2019) - doi: 10.3832/ifor3072-012
https://iforest.sisef.org/contents/?id=ifor3072-012

Research Articles: The influence of age and crown position on growth efficiency along a Scots pine chronosequence

2019-10-14

Turski M, Kwasna H, Beker C, Jaszczak R, Kazmierczak K, Najgrakowski T, Borzyszkowski W

THE INFLUENCE OF AGE AND CROWN POSITION ON GROWTH EFFICIENCY ALONG A SCOTS PINE CHRONOSEQUENCE

Abstract: The study deals with the effects of age and crown position (either dominant or intermediate, as determined by Kraft’s social class) on stemwood growth efficiency (GE), which is viewed as the ratio of annual stemwood volume increment of the previous five years to needle volume of the entire tree, in eight even-aged pure stands of Scots pine (Pinus sylvestris L.). The highest GE was observed in the youngest stands, and the lowest in the oldest ones. There was no clear interdependence of GE on the age of intermediate stands. GE was most variable in the youngest, the 25-year-old stand, and was the least variable in the 74-year-old stand. GE in dominant trees was lower in 25- 74- and 85-year-old stands and higher in 33-, 44-, 56-, 64- and 93-year-old stands. The GE ratios of dominant trees to intermediate trees in 25-, 33-, 44-, 56-, 64-, 74-, 85- and 93-year-old stands were 0.47:1, 1:0.93, 1:0.87, 1:0.81, 1:0.86, 0.88:1, 0.90:1 and 1:0.61, respectively. Tree age had a statistically significant effect on GE; however, the contribution of the age factor to GE was assessed as weak. Generally, the position of trees (whether dominant or intermediate) had no effect on GE, while age × position of trees had a statistically significant effect on GE, which means that the two factors interacted. The correlation between GE and tree height, diameter at breast height (DBH), and the needle volume of the entire empirical material was statistically significant with a negative sign; however, the situation varied among the particular stands.

Keywords: Pine, Needle Volume, Growth Efficiency, Dominant Trees, Intermediate Trees

iForest 12 (5): 474-479 (2019) - doi: 10.3832/ifor2953-012
https://iforest.sisef.org/contents/?id=ifor2953-012

Research Articles: Classification and mapping of Spanish Mediterranean mixed forests

Sánchez de Dios R, Velázquez JC, Sainz Ollero H — 2019-10-14

Sánchez de Dios R, Velázquez JC, Sainz Ollero H

CLASSIFICATION AND MAPPING OF SPANISH MEDITERRANEAN MIXED FORESTS

Abstract: Mixed forests play an important role in promoting forest functions and services, and showed better resilience to perturbations than monospecific forests. In the Mediterranean Basin they constitute an important share of the total forest area. However, although mixed forests have been described, classified and mapped in most of the Mediterranean regions around the world, in the Mediterranean Basin they remain neglected, with direct negative consequences for forest management and conservation strategies. Our objective is to present a reliable, uniform classification along with a map of the Spanish Mediterranean Mixed Forests (MMF) as a tool for their management and conservation in Spain. The digital Spanish Forest Map was analyzed to identify MMF. The most frequent tree species combinations were identified and their representativeness in terms of the total forest area was analyzed. In addition, to ensure environmental homogeneity in the proposed classification, the arrangement of each tree species combination within the Spanish Mediterranean ecoregions was evaluated using the Pearson Chi-square test. Based on our results, Spanish MMF currently cover 27.07% of the Mediterranean natural forest area. They were divided into 9 main ecological groups and 23 subtypes. The classification of Spanish MMF and the distribution map represent a first step towards recognizing the importance of mixed forests in the vegetation of the Mediterranean Basin. Together they may provide a valuable basis to improve future forest management, monitoring and conservation strategies both at national and European level.

Keywords: Mixed Forests, Mediterranean Forests, Vegetation Classification, Forest Map, Mediterranean Mixed Forest

iForest 12 (5): 480-487 (2019) - doi: 10.3832/ifor2817-012
https://iforest.sisef.org/contents/?id=ifor2817-012

Research Articles: Distribution and abundance of the alien Xylosandrus germanus and other ambrosia beetles (Coleoptera: Curculionidae, Scolytinae) in different forest stands in central Slovenia

Hauptman T, Pavlin R, Grošelj P, Jurc M — 2019-09-29

Hauptman T, Pavlin R, Grošelj P, Jurc M

DISTRIBUTION AND ABUNDANCE OF THE ALIEN XYLOSANDRUS GERMANUS AND OTHER AMBROSIA BEETLES (COLEOPTERA: CURCULIONIDAE, SCOLYTINAE) IN DIFFERENT FOREST STANDS IN CENTRAL SLOVENIA

Abstract: The East Asian ambrosia beetle (Xylosandrus germanus - Blandford 1894) is an invasive species that has become successfully established in Europe and North America. In Slovenia, X. germanus was first recorded in 2000 in the western part of the country, and since 2008 the species has also been identified in other parts of Slovenia. The first economic damage was recorded in 2016 after a massive attack on recently felled logs of different tree species, spurring research into this non-native invasive species. To examine the distribution and abundance of X. germanus compared to other ambrosia beetles and to determine voltinism and the flight period of the species in our climatic conditions, we deployed 19 ethanol-baited traps from March to November 2017 in oak-, beech- and fir-dominated forest stands in central Slovenia. To verify the vertical distribution of X. germanus, traps were installed at altitudes ranging from 303 m to 941 m a.s.l. Furthermore, the impact of the ice storm that hit Slovenia in 2014 on the abundance of X. germanus was also studied. Non-native X. germanus represented 71.8% of the total catch and was significantly more abundant than the other five most common species: Xyleborinus saxesenii (20.0%), Xyleborus monographus (3.6%), Anisandrus dispar (2.5%), Trypodendron domesticum (1.2%) and Trypodendron signatum (0.6%). X. germanus was most abundant in beech-dominated stands, but the differences between forest types were not significant. The species was found along the entire altitudinal gradient. Our results indicate that the swarming of X. germanus in lowland forests may already occur by the middle of March. Maximum flying activity was observed in May and early June in forests below 600 m a.s.l. and at the end of May and in June in forests above 700 m a.s.l. Only one generation per year was observed. The ice storm positively affected the abundance of X. germanus, especially in areas where sanitary logging was delayed. Xyleborinus attenuatus was detected for the first time in Slovenia.

Keywords: Xylosandrus germanus, Ambrosia Beetles, Black Timber Bark Beetle, Invasive Species, Habitat Preference, Monitoring, Ethanol-baited Traps

iForest 12 (5): 451-458 (2019) - doi: 10.3832/ifor3114-012
https://iforest.sisef.org/contents/?id=ifor3114-012

Research Articles: Preliminary study on genetic variation of growth traits and wood properties and superior clones selection of Populus ussuriensis Kom.

Jin J, Zhao X, Liu H, Wang S, Song Z, Ma X, Li K — 2019-09-29

Jin J, Zhao X, Liu H, Wang S, Song Z, Ma X, Li K

PRELIMINARY STUDY ON GENETIC VARIATION OF GROWTH TRAITS AND WOOD PROPERTIES AND SUPERIOR CLONES SELECTION OF POPULUS USSURIENSIS KOM.

Abstract: In this study the genetic variation of growth traits and wood properties was assessed in 45 clones of Populus ussuriensis Kom. grown in a 10-year-old experimental forest located in Northeastern China and a preliminary selection of superior clones was performed based on multi-trait selection index. The following traits were analyzed: tree height, H; diameter at breast height, DBH; volume, V; basic wood density, BWD; fiber length, FL; fiber length-width ratio, FL/W; microfibril angle, MA; cell wall percentage, CWP; fiber double wall thickness, FWT; vessel proportion, VP; wood fiber proportion, FP; wood ray proportion, RP; holocellulose content, HC. The results revealed significant differences (P<0.05) in DBH, V, BWD, FWT, VP and FP among different clones. Broad-sense heritabilities for growth traits and wood properties ranged from 0.020 to 0.749, therefore growth traits and wood properties are moderately or weakly controlled. Negative correlations between growth traits and most wood properties were also found. According to the multi-trait selection index at a selected rate of 10% and survival rates, 3 superior clones (I18, H16, C13) were selected, and the DBH, V, BWD, FL and FP of superior clones were higher than those of all clones by 2.83%, 9.81%, 3.40%, 6.59% and 0.31%, the MA, FWT, VP were lower than those of all clones by 7.54%, 0.39%, 2.12%, respectively. These superior clones could be used as starting breeding material for P. ussuriensis.

Keywords: Populus ussuriensis Kom., Growth Traits, Wood Properties, Genetic Variation, Multi-trait Index Selection

iForest 12 (5): 459-466 (2019) - doi: 10.3832/ifor2991-012
https://iforest.sisef.org/contents/?id=ifor2991-012

Research Articles: Spatial structure of the vertical layers in a subtropical secondary forest 57 years after clear-cutting

Li Y, He J, Yu S, Zhu D, Wang H, Ye S — 2019-09-16

Li Y, He J, Yu S, Zhu D, Wang H, Ye S

SPATIAL STRUCTURE OF THE VERTICAL LAYERS IN A SUBTROPICAL SECONDARY FOREST 57 YEARS AFTER CLEAR-CUTTING

Abstract: Stratification is an important phenomenon in natural forests. The mixed pine-oak forests along the Nanpan River in southwest China was clearly formed by two layers in the vertical direction. These forests developed in an area where the virgin forests suffered clear-cutting. After excluding habitat heterogeneity, we divided two plots into upper and lower layers according to the tree height, and then analyzed the spatial pattern, species distribution, and size differentiation using the pair correlation function g(r) and the mark correlation function (MCF) kmm (r), respectively. The following key results were obtained: (1) the upstory was slightly clustered, whereas the understory had an intensively clumped pattern. An uneven pattern of germplasm resources in the early stages of succession and seed dispersion limitation may have contributed to the aggregation of tree species. (2) The spatial correlation among the main populations in each layer, and between both layers, had a largely random association, suggesting that differences in tree growth and physiological characteristics play an important role in species association. (3) Species aggregation decreased as the observation scale increased; however, the aggregation intensity of the understory was significantly higher than that of the upstory, which may be related to negative density dependence and niche complementarity. (4) Size differentiation in the upstory was significant, with small trees gathered together. There were no obvious differences in tree size in the lower layer, indicating a higher competitive pressure among trees in the upper layer. In conclusion, the spatial structure of trees in terms of vertical stratification differs, which is of great significance for investigating the mechanisms by which species coexist.

Keywords: Clear Cut, Secondary Forest, Size Differentiation, Spatial Pattern, Stratification

iForest 12 (5): 442-450 (2019) - doi: 10.3832/ifor2975-012
https://iforest.sisef.org/contents/?id=ifor2975-012

Research Articles: Essential environmental variables to include in a stratified sampling design for a national-level invasive alien tree survey

Kotze JD, Beukes HB, Seifert T — 2019-09-01

Kotze JD, Beukes HB, Seifert T

ESSENTIAL ENVIRONMENTAL VARIABLES TO INCLUDE IN A STRATIFIED SAMPLING DESIGN FOR A NATIONAL-LEVEL INVASIVE ALIEN TREE SURVEY

Abstract: There is a direct relationship between the abundance of biological invasions and their impact, which means that it is important to capture spatial patterns in their abundance and use this information to focus management actions. However, protocols to objectively determine invasive alien plant (IAP) distributions and abundance are lacking at a national level, resulting in the inability to determine and monitor changes in spatial extent and density over time. A complete inventory of IAP spatial distribution across an extensive area such as South Africa is not possible and so requires an efficient sampling approach. A simple random sampling design would not be efficient, so monitoring of IAP species at a national level requires an appropriate sampling design such as a stratified sampling. The selection of environmental variables to be included in such a stratification should be based on the relationship between IAP species and their physical environment to successfully summarize variance in their abundance within the different strata. A further objective is to obtain all possible combinations of environmental variables or a full rank design in the stratification to allow for the comparison of different strata based on actual field sampled data. This raises the question of which predictive environmental variables as well as how many to include in the stratification. For this purpose, three invasive tree species, namely Acacia cyclops, Acacia mearnsii and Prosopis glandulosa were selected as they cover the maximum possible area at the highest density with the least amount of geographic overlap. A total of 26 environmental variables that included climatic, soil and topographic type variables were tested with linear regressions against correlations with the abundance of those tree species. The results showed that a combination of average precipitation, soil depth, clay content in the B-horizon and terrain morphological units will serve as a suitable stratification at a national level to explain IAP abundance variation sufficiently well whilst retaining a full rank design. These results will be applied as the first phase in the formation of a regional level IAP monitoring programme for South Africa on a scientific basis.

Keywords: Invasive Alien Plant (IAP) Species, Monitoring, Sampling Design, Stratification, Environmental Variables

iForest 12 (5): 418-426 (2019) - doi: 10.3832/ifor2767-012
https://iforest.sisef.org/contents/?id=ifor2767-012

Research Articles: Evaluation of hydrological and erosive effects at the basin scale in relation to the severity of forest fires

Coschignano G, Nicolaci A, Ferrari E, Cruscomagno F, Iovino F — 2019-09-01

Coschignano G, Nicolaci A, Ferrari E, Cruscomagno F, Iovino F

EVALUATION OF HYDROLOGICAL AND EROSIVE EFFECTS AT THE BASIN SCALE IN RELATION TO THE SEVERITY OF FOREST FIRES

Abstract: This study aimed to assess the hydrological and erosive effects of different levels of the fire severity in the drainage basin of the Trionto River (Calabria, southern Italy), which was partially burned by intense fires during the summer 2017. The analysis focused on the identification of wildfire areas using a supervised classification of remote sensing images with the minimum distance algorithm. The level of severity of each fire was then discriminated based on a procedure proposed by the U.S. Department of Agriculture and adapted to the study area. To evaluate how wildfire occurrence affects the hydrological behaviour at the basin scale, the SCS-Curve Number model was used to document pre- and post-fire conditions in relation with the level of fire severity. Finally, the influence on erosion was analysed for analogous conditions at the basin scale using the RUSLE equation. The effects on hydrological balance and soil loss were evaluated by comparing the pre-fire value with three different post-fire scenarios: (a) different levels of severity on the surface covered by the fire (real case); (b) maximum level of severity on the surface covered by the fire; (c) total loss of the canopy and formation of a hydrophobic layer on the surface soil. The results confirmed that the level of severity of the forest fires, combined with climatic factors, morphological conditions, and the pedological characteristics of the basin, significantly influence changes to the hydrology and rates of erosion. Moreover, these impacts proved to be mainly dependent on the consequent, often notable, heterogeneity in the spatial distribution of burned areas with different severity.

Keywords: Forest Fire Severity, Hydrological Impacts, Soil Loss Estimation, Remote Sensing

iForest 12 (5): 427-434 (2019) - doi: 10.3832/ifor2878-012
https://iforest.sisef.org/contents/?id=ifor2878-012

Research Articles: Accuracy assessment of different photogrammetric software for processing data from low-cost UAV platforms in forest conditions

Brach M, Chan JCW, Szymanski P — 2019-09-01

Brach M, Chan JCW, Szymanski P

ACCURACY ASSESSMENT OF DIFFERENT PHOTOGRAMMETRIC SOFTWARE FOR PROCESSING DATA FROM LOW-COST UAV PLATFORMS IN FOREST CONDITIONS

Abstract: To obtain precise cartometric measurements of forests is always a challenge and high-resolution data from Unmanned Aerial Vehicle (UAV) is currently the quickest method. Generation of a fine quality orthomosaic of the acquired image series is a pre-requisite for full exploitation of such data. This study examines six of the most frequently used photogrammetric software for popular and inexpensive UAV systems. It is assumed that ground control points (GCPs) are not required. The average Root Mean Square Error (RMSE) for raw orthophoto was 1.24 m and around 0.2 m precision for both X and Y axes. Additionally, the accuracy of UAV internal GNSS receiver was checked on reference points which slightly exceeds 2 m RMSE. The range of accuracy and precision of orthomosaic are provided as a valuable reference for the use of low-cost UAV in forest inventory.

Keywords: UAV, GNSS, Orthomosaic, Accuracy, Precision, Forest

iForest 12 (5): 435-441 (2019) - doi: 10.3832/ifor2986-012
https://iforest.sisef.org/contents/?id=ifor2986-012

Research Articles: Photosynthetic parameters of urban greening trees growing on paved land

Wang X, Wang X, Chen Y, Berlyn GP — 2019-08-13

Wang X, Wang X, Chen Y, Berlyn GP

PHOTOSYNTHETIC PARAMETERS OF URBAN GREENING TREES GROWING ON PAVED LAND

Abstract: Two common urban greening trees, ash (Fraxinus chinensis Roxb.) and maple (Acer truncatum Bunge.), were planted in arranged pervious and impervious land pavements to clarify the response in the photosynthetic processes of the urban tree under different types of pavement. Leaf light and CO2 response curves of the net photosynthetic rate were constructed based on in situ measurements in the 4th year after planting, and additional photosynthetic parameters were obtained. The surface temperature and soil temperature significantly increased while the soil moisture significantly decreased in the land pavement, and these changes varied with types of pavement. The light-saturated net photosynthetic rates of both ash and maple, the saturated intercellular CO2 concentration of ash, and the light saturation point, CO2-saturated net photosynthetic rate and maximum carboxylation rate of maple significantly decreased in impervious pavement, indicating that both the capacity of leaf photosynthesis and utilization of high light and CO2 concentrations were significantly reduced by land pavement. The down-regulation of photosynthesis in the impervious pavement was mainly due to the reduction of available soil water. Photosynthetic parameters of maple showed more sensitivity to the land pavement than those of ash. There was less impact from pervious pavement than impervious pavement on the photosynthetic parameters of ash and maple.

Keywords: Impervious Pavement, Pervious Pavement, Photosynthesis, Photosynthetic Parameter, Urban Tree

iForest 12 (4): 403-410 (2019) - doi: 10.3832/ifor2939-012
https://iforest.sisef.org/contents/?id=ifor2939-012

Research Articles: Fungal community of necrotic and healthy galls in chestnut trees colonized by Dryocosmus kuriphilus (Hymenoptera, Cynipidae)

Muñoz-Adalia EJ, Rodríguez D, Casado M, Diez J, Fernández M — 2019-08-13

Muñoz-Adalia EJ, Rodríguez D, Casado M, Diez J, Fernández M

FUNGAL COMMUNITY OF NECROTIC AND HEALTHY GALLS IN CHESTNUT TREES COLONIZED BY DRYOCOSMUS KURIPHILUS (HYMENOPTERA, CYNIPIDAE)

Abstract: Dryocosmus kuriphilus is a non-native pest that has recently spread through Europe with a special incidence along the Mediterranean Basin. The presence of this exotic wasp (originally from Asia) threatens stands and orchards of sweet chestnut (Castanea sativa Mill.) as it reduces tree growth and consequently fruit production. In this study the living mycobiota in leaves, healthy and necrotic galls collected from two sites in Cantabria (Northern Spain) was investigated. A total of twenty-two fungal taxa based on morphological and molecular traits were determined. In addition, we calculated fungal diversity and identified the dominant taxa among members of the mycobiota. Seven log-linear models were used to analyse whether fungal abundance varied between sites, types of plant material or fungal taxa. Our findings highlight the complex interactions between plant hosts, insect and the endophytic community, and are of potential interest in relation to the biological control of this important pest.

Keywords: ACGW, Biological Control, Castanea sativa, Endophytic Fungi, Entomopathogens, Fungal Community, Necrotic Gall

iForest 12 (4): 411-417 (2019) - doi: 10.3832/ifor3014-012
https://iforest.sisef.org/contents/?id=ifor3014-012

Research Articles: Wintertime photosynthesis and spring recovery of Ilex aquifolium L.

Wachendorf M, Schloz M, Küppers M, Güney A, Veste M — 2019-07-31

Wachendorf M, Schloz M, Küppers M, Güney A, Veste M

WINTERTIME PHOTOSYNTHESIS AND SPRING RECOVERY OF ILEX AQUIFOLIUM L.

Abstract: Former studies using the chlorophyll fluorescence technique on evergreen Ilex aquifolium L. showed that its photosynthetic potential for electron transport in winter recovers quickly when exposed to more favorable conditions. Since little is known, however, about its photosynthetic carbon gain in winter, we investigated its leaf gas exchange over an entire winter and spring period. Measurements were made rotationally in the field and in the laboratory to also investigate if I. aquifolium profits from warmer phases during winter in terms of net carbon gain. From the end of autumn until the end of spring, three different climate-driven phases of photosynthetic responses could be distinguished: first, an acclimation phase which lasted until February and was characterized by a gradually decreasing light-saturated gross photosynthesis (Amax(gross)), decreasing apparent quantum yield of CO2-assimilation (ΦΦi) and a decreasing ability of these parameters to recover overnight inside the laboratory. At the same time, maximal quantum yield of PSII (Fv/Fm) could fully regenerate. In this phase, single warmer days had a positive effect on carbon assimilation. Second, a phase of relatively constant but low photosynthesis which was virtually unaffected by temperature, lasting for almost two months occurred. Here, Amax(gross) and Φi had lost their ability to recover from winter conditions in the field, while Fv/Fm was much less affected. I. aquifolium was still able to conduct positive light-saturated net photosynthesis at a leaf temperature of -0.5 °C, but during this time it could not profit from milder temperatures in terms of carbon gain. Third, a phase of increasing photosynthesis (spring recovery) occurred, starting in March when the 5-day average temperature was above 5 °C and radiation in the field increased, and where all parameters slowly recovered from winter depressions. Our findings show that I. aquifolium is photosynthetically active over the whole winter, even at temperatures around 0 °C. In terms of carbon gain, however, I. aquifolium does not profit from warmer phases during winter, despite the fast recovery seen in chlorophyll fluorescence measurements.

Keywords: Chlorophyll Fluorescence, Frost, Leaf Gas Exchange, Photosynthetic Induction, Quantum Yield, Respiration

iForest 12 (4): 389-396 (2019) - doi: 10.3832/ifor2983-012
https://iforest.sisef.org/contents/?id=ifor2983-012

Research Articles: Near zero mortality in juvenile Pinus hartwegii Lindl. after a prescribed burn and comparison with mortality after a wildfire

Hernández-Correa R, Rodríguez-Trejo DA, Cruz-Reyes A — 2019-07-31

Hernández-Correa R, Rodríguez-Trejo DA, Cruz-Reyes A

NEAR ZERO MORTALITY IN JUVENILE PINUS HARTWEGII LINDL. AFTER A PRESCRIBED BURN AND COMPARISON WITH MORTALITY AFTER A WILDFIRE

Abstract: Fire is considered a relevant ecological factor, however, human alterations of fire regime facilitate more destructive wildfires. The aims of this work were to model probability of tree mortality and to identify the factors associated with leader shoot growth in a prescribed burn area and in a nearby wildfire area in a juvenile Pinus hartwegii Lindl. stand in central Mexico. A prescribed burn was carried out in 10-ha stand in March 2012, and compared with a close area affected by a wildfire occurred one week later, as well as with a nearby unburned area taken as control. A logistic model was used to estimate the probability of mortality, and a linear regression model was employed to investigate factors related to leader shoot growth. No tree mortality was recorded in the unburned control. In contrast, mortality was 6% in the prescribed burn and 66.9% in the wildfire area. The probability of mortality was influenced by stem char height (positively, p<0.0001), tree height (negatively, p=0.0443), and diameter at breast height (negatively, p<0.0001). The variables that had more influence on leader shoot growth were stem char height (negatively, p<0.0001) and tree height (positively, p<0.0001). This work supports evidence of the feasibility of using low intensity prescribed burns in this ecosystem with minimum effects on young tree mortality.

Keywords: Fire Adaptations, Fire Ecology, Integral Fire Management, Prescribed Burning, Probability of Mortality, Logistic Regression, Pinus hartwegii

iForest 12 (4): 397-402 (2019) - doi: 10.3832/ifor2760-012
https://iforest.sisef.org/contents/?id=ifor2760-012

Research Articles: Carbon and nutrient contents in the miscellaneous fraction of litterfall under different thinning intensities in a semiarid Pinus halepensis afforestation

Segura C, Fernández-Ondoño E, Jiménez MN, Navarro FB — 2019-07-12

Segura C, Fernández-Ondoño E, Jiménez MN, Navarro FB

CARBON AND NUTRIENT CONTENTS IN THE MISCELLANEOUS FRACTION OF LITTERFALL UNDER DIFFERENT THINNING INTENSITIES IN A SEMIARID PINUS HALEPENSIS AFFORESTATION

Abstract: Litterfall evaluation and the effects caused by forestry practices provide valuable information on nutrient-cycle dynamics in managed forests. So far, most of the studies have focused on leaf-fall, omitting other litterfall fractions that can be also relevant for forest and soil modelling in a global change context. With this aim the miscellaneous fraction was quantified in a Pinus halepensis afforestation in the semiarid SE of Spain five years after four different thinning regimes were applied (T75: 75% of mean basal area removed; T60: 60%; T48: 48%; and T0: no thinning). Concentrations and pools (kg ha-1) of carbon and nutrients in the miscellanea fraction were monthly analysed for C and N (June 2010-May 2013), and for P, K, Na, Ca, Mg, Fe, Zn, and Mn (June 2011-May 2013). No differences in concentrations of carbon and nutrients were found among treatments with the exception of N, which showed significant differences between T75 and T60 plots. For pools, a high variability was found over time with maximum C and N pools found during spring, likely reflecting the influence of Thaumetopoea pityocampa attacks. Thinning affected C, N, Mn, and Zn pools in 2011-2012 period, and P, K, Ca, Mg, Mn, Fe, and Zn pools in 2012-2013. Significant differences were mainly found between the most intensive treatment (T75) and unthinned plots (T0). The percentage of annual mean C and nutrient pools in miscellanea showed the importance of its monitoring, with pools that represented from 43.0% to 57.9% of the total litterfall for C (278.81-746.01 kg ha-1 yr-1), N (4.18-10.44 kg ha-1 yr-1), and P (0.37-1.43 kg ha-1 yr-1). Our results stress the high relevance of miscellany monitoring in order to gain a better understanding of nutrient cycles in forest ecosystems.

Keywords: Mediterranean Region, Aleppo Pine, Micro- and Macronutrient Concentrations, Nutrient Dynamics, C Inputs, Pine Processionary

iForest 12 (4): 375-382 (2019) - doi: 10.3832/ifor2907-012
https://iforest.sisef.org/contents/?id=ifor2907-012

Research Articles: Impact of forest management on threatened epiphytic macrolichens: evidence from a Mediterranean mixed oak forest (Italy)

2019-07-12

Paoli L, Benesperi R, Fačkovcová Z, Nascimbene J, Ravera S, Marchetti M, Anselmi B, Landi M, Landi S, Bianchi E, Di Nuzzo L, Lackovičová A, Vannini A, Loppi S, Guttová A

IMPACT OF FOREST MANAGEMENT ON THREATENED EPIPHYTIC MACROLICHENS: EVIDENCE FROM A MEDITERRANEAN MIXED OAK FOREST (ITALY)

Abstract: Forest management practices may heavily affect epiphytic cryptogams. This study was conceived in March 2016, as soon as we were informed about an authorized logging for timber within a Mediterranean mixed oak forest in Tuscany (central Italy), which threatened a large population of the forest macrolichen Lobaria pulmonaria (L.) Hoffm., composed of hundreds of fertile thalli. Lobaria pulmonaria is often used as an ecological indicator of high quality habitats hosting rare lichens, and in general, cryptogams worthy of conservation. The species has suffered a general decline throughout Europe as a consequence of air pollution and intensive forest management, and currently it is red-listed in several countries, where it is considered also as a “flag species”. We estimated that 40% of the lichen biomass (8.5-12.3 kg ha-1) has been lost due to logging operations (in the core area, up to 1.8 kg every 100 m2), in particular large and fertile thalli. One year after the conclusion of logging operations, the analysis of chlorophyll fluorescence emission (indicator of the photosynthetic performance of the lichen photobionts), revealed a significant reduction of the vitality of the thalli on retained-isolated trees. The article provides issues for conservation in Mediterranean oak forests and outlines the outmost importance of ensuring the safeguard of forest ecosystems hosting fertile populations of this model species, especially in the case of unprotected forests.

Keywords: Biomass Loss, Chlorophyll Fluorescence, Flag Species, Legal Protection, Lobaria pulmonaria, Red Lists

iForest 12 (4): 383-388 (2019) - doi: 10.3832/ifor2951-012
https://iforest.sisef.org/contents/?id=ifor2951-012

Research Articles: Spatio-temporal modelling of forest monitoring data: modelling German tree defoliation data collected between 1989 and 2015 for trend estimation and survey grid examination using GAMMs

Eickenscheidt N, Augustin Nicole H, Wellbrock N — 2019-07-05

Eickenscheidt N, Augustin Nicole H, Wellbrock N

SPATIO-TEMPORAL MODELLING OF FOREST MONITORING DATA: MODELLING GERMAN TREE DEFOLIATION DATA COLLECTED BETWEEN 1989 AND 2015 FOR TREND ESTIMATION AND SURVEY GRID EXAMINATION USING GAMMS

Abstract: Spatio-temporal modelling of tree defoliation data from the German forest condition survey is statistically challenging, particularly due to irregular grids. In the present study, generalized additive mixed models (GAMMs) were used to estimate the spatio-temporal trends in defoliation of the main tree species spruce, pine, beech and oak from 1989 to 2015 and to examine the suitability of different monitoring grid resolutions (standard 16 × 16 km grid and denser grids). Although data has been collected since 1989, this is the first time spatio-temporal modelling for all of Germany has been carried out. GAMMs proved to be a statistically sound and highly flexible choice for spatio-temporal modelling of defoliation data. In addition to the space-time component, stand age showed a significant effect on defoliation. The mean age and the species-specific relation between defoliation and age determined the general level of defoliation. However, further investigations are necessary in order to understand what is behind the age effect. Adjustment for stand age was carried out for identifying hotspots of high defoliation that are not merely the result of the age effect. Fluctuations in defoliation were most likely related to weather conditions. South-western Germany has emerged as the region with the highest defoliation since the drought year 2003. This region was characterized by the strongest water deficits in 2003 compared to the long-term reference period (1961-1990). Furthermore, the spatio-temporal model was used to carry out a simulation study to compare different survey grid resolutions in terms of prediction error. The model-based approach for grid analysis turned out to be appropriate for the given data and sample design. The grid analysis indicated that an 8 × 8 km grid instead of the standard 16 × 16 km grid is necessary for spatio-temporal trend estimation and for detecting hotspots in defoliation in space and time, especially regarding oaks.

Keywords: Age Effect, Drought Stress, Forest Condition Survey, Generalized Additive Mixed Models, Grid Examination, Spatio-temporal Model, Survey Design, Tensor Product Smooth

iForest 12 (4): 338-348 (2019) - doi: 10.3832/ifor2932-012
https://iforest.sisef.org/contents/?id=ifor2932-012

Research Articles: Geographic determinants of spatial patterns of Quercus robur forest stands in Latvia: biophysical conditions and past management

Rendenieks Z, Brumelis G, Nikodemus O, Elferts D — 2019-07-05

Rendenieks Z, Brumelis G, Nikodemus O, Elferts D

GEOGRAPHIC DETERMINANTS OF SPATIAL PATTERNS OF QUERCUS ROBUR FOREST STANDS IN LATVIA: BIOPHYSICAL CONDITIONS AND PAST MANAGEMENT

Abstract: Most of the forest area dominated by pedunculate oak (Quercus robur L.) in Latvia was lost to arable land several centuries ago and the remnant patches of Q. robur stands are small and spatially scattered. We hypothesized that a large part of the present Q. robur stands in the Eastern Baltic area of the hemiboreal forest zone developed around the past manor houses in the period of social and political turmoil and subsequent agricultural land abandonment. Our aim was to determine the relationship of Q. robur stand occurrence with soil properties, climatic conditions and proximity to past manor houses. Our study area was the entire territory of Latvia (64.589 km2), divided into 16 landscape regions. We used the State Forest Inventory database to filter out all stands dominated by Q. robur (n=3746). Spatial aggregation of the stands was tested by multi-distance spatial clustering analysis (Ripley’s K method). Mean stand area and Euclidean nearest-neighbour distance for stands were calculated for landscape regions. Binary logistic regression with the calculation of autocovariates showed that winter temperature, soil texture, carbonate concentration and distance to closest manor house were the independent factors significantly (p<0.01) related to the probability of occurrence of Q. robur stands. The results showed that Q. robur is spatially clustered, i.e., significantly different from a random distribution (p<0.05). Higher densities of stands occurred in landscape regions with milder maritime climatic conditions. The largest proportional area of stands established between 1885 and 1914 in the period when peasants gained title to lands and manor lords lost control over their land holdings. In addition, in the landscape regions of Rietumkursa, Austrumkursa and Rietumzemgale, the abundance of Q. robur stands coincided with high densities of past manor houses. Thus, establishment of the Q. robur stands likely responded to suitable conditions (open canopy) made available for tree colonization during the land reform occurred 100 years ago. Our results suggest that priority for conservation should be given to spatial aggregations of stands with high connectivity and on richer soils in more maritime conditions.

Keywords: Forest Management, Geographic Distribution, Land Use History, Soil, Manor, Spatial Pattern, Quercus robur

iForest 12 (4): 349-356 (2019) - doi: 10.3832/ifor2979-012
https://iforest.sisef.org/contents/?id=ifor2979-012

Research Articles: Effect of different dolomitic limestone dosages on soil respiration in a mid-altitudinal Norway spruce stand

Rosíková J, Darenova E, Kučera A, Volarík D, Vranová V — 2019-07-05

Rosíková J, Darenova E, Kučera A, Volarík D, Vranová V

EFFECT OF DIFFERENT DOLOMITIC LIMESTONE DOSAGES ON SOIL RESPIRATION IN A MID-ALTITUDINAL NORWAY SPRUCE STAND

Abstract: The study focuses on the effect of chemical amelioration of dolomitic limestone (doses of 0, 2, 3, 4, 6, 9 and 26 t ha-1) on soil respiration in a Norway spruce monoculture in mid-altitudinal elevation during one-year period after application. Firstly, the soil respiration was measured in situ as monthly CO2 efflux from the soil surface horizon in the period May to October 2016. Secondly, basal respiration, microbial biomass carbon and metabolic quotient of the organic H and organo-mineral A horizons were assessed under laboratory conditions within one year after the treatment. Soil CO2 efflux increased by 3 to 31% and by 29 to 98% for the ameliorant of 2 and 26 t ha-1, respectively, compared to the unlimed control treatment. The CO2 efflux was significantly driven by external conditions such as soil moisture and temperature, especially in the last seasonal months. Basal respiration of the H horizon increased up to a dose of 9 t ha-1 but decreased at 26 t ha-1. In the A horizon, microbial activity increased in all the limed variants compared to the non-limed variant. A similar trend was observed in microbial carbon and the metabolic quotient of the soil. Our results prove that the ameliorant doses commonly used in the forestry sector (3-4 t ha-1) substantially increase the soil microbial activity during (soil CO2 efflux) and after (laboratory data) the first year after application. This results in the accelerated mineralization of soil organic material and subsequent loss from the forest ecosystem.

Keywords: Amelioration, Basal Respiration, Liming, Picea abies, Soil CO2 Efflux

iForest 12 (4): 357-365 (2019) - doi: 10.3832/ifor2894-012
https://iforest.sisef.org/contents/?id=ifor2894-012

Research Articles: Large scale semi-automatic detection of forest roads from low density LiDAR data on steep terrain in Northern Spain

Prendes C, Buján S, Ordoñez C, Canga E — 2019-07-05

Prendes C, Buján S, Ordoñez C, Canga E

LARGE SCALE SEMI-AUTOMATIC DETECTION OF FOREST ROADS FROM LOW DENSITY LIDAR DATA ON STEEP TERRAIN IN NORTHERN SPAIN

Abstract: While forest roads are important to forest managers in terms of facilitating the exploitation of wood and timber, their role is far more multifunctional. They permit access to emergency services in the case of forest fires as well as acting as fire breaks, enhance biodiversity, and provide access to the public to enjoy recreational activities. Detailed maps of forest roads are an essential tool for better and more timely forest management and automatic/semi-automatic tools allow not only the creation of forest road databases, but also enable these to be updated. In Spain, LiDAR data for the entire national territory is freely available, and the capture of higher density data is planned in the next few years. As such, the development of a forest road detection methodology based on LiDAR data would allow maps of all forest roads to be developed and regularly updated. The general objective of this work was to establish a low density LiDAR data-based methodology for the semi-automatic detection of the centerline of forest roads on steep terrain with various types of canopy cover. Intensity and slope images were generated using the currently available LiDAR data of the study area (0.5 points m-2). Two image classification approaches were evaluated: pixel-based and object-oriented classification (OBIA). The LiDAR-derived centerlines obtained with the two approaches were compared with the real centerlines which had previously been digitized in the field. The road width, type of surface and type of vegetation cover were also recorded. The effectiveness of the two approaches was evaluated through three quality indicators: correctness, completeness and quality. In addition, the accuracy of the LiDAR-derived centerlines was also evaluated by combining GIS analysis and statistical methods. The pixel-based approach obtained higher values than OBIA for two of the three quality measures (correctness: 93% compared to 90%; and quality: 60% compared to 56%) as well as in terms of positional accuracy (± 5.5 m vs. ± 6.8 for OBIA). The results obtained in this study demonstrate that producing road maps is among the most valuable and easily attainable products of LiDAR data analysis.

Keywords: GIS, Pixel-based Classification, OBIA, Quality Measures, Forest Roads Network, Accuracy Assessment

iForest 12 (4): 366-374 (2019) - doi: 10.3832/ifor2989-012
https://iforest.sisef.org/contents/?id=ifor2989-012

Research Articles: Prediction of stem diameter and biomass at individual tree crown level with advanced machine learning techniques

Malek S, Miglietta F, Gobakken T, Næsset E, Gianelle D, Dalponte M — 2019-06-14

Malek S, Miglietta F, Gobakken T, Næsset E, Gianelle D, Dalponte M

PREDICTION OF STEM DIAMETER AND BIOMASS AT INDIVIDUAL TREE CROWN LEVEL WITH ADVANCED MACHINE LEARNING TECHNIQUES

Abstract: Knowledge about the aboveground biomass (AGB) and the diameters at breast height (DBH) distribution can lead to a precise estimation of carbon density and forest structure which can be very important for ecology studies especially for those concerning climate change. In this study, we propose to predict DBH and AGB of individual trees using tree height (H) and crown diameter (CD), and other metrics extracted from airborne laser scanning (ALS) data as input. In the proposed approach, regression methods, such us support vector machine for regression (SVR) and random forests (RF), were used to find a transformation or a transfer function that links the input parameters (H, CD, and other ALS metrics) with the output (DBH and AGB). The developed approach was tested on two datasets collected in southern Norway comprising 3970 and 9467 recorded trees, respectively. The results demonstrate that the developed approach provides better results compared to a state-of-the-art work (based on a linear model with the standard least-squares method) with RMSE equal to 81.4 kg and 92.0 kg, respectively (compared to 94.2 kg and 110.0 kg) for the prediction of AGB, and 5.16 cm and 4.93 cm, respectively (compared to 5.49 cm and 5.30 cm) for DBH.

Keywords: Aboveground Biomass, Diameter at Breast Height, Airborne Laser Scanning (ALS), Remote Sensing (RS), Support Vector Machine for Regression (SVR), Random Forests (RF)

iForest 12 (3): 323-329 (2019) - doi: 10.3832/ifor2980-012
https://iforest.sisef.org/contents/?id=ifor2980-012

Research Articles: Pollen contamination and mating patterns in a Prosopis alba clonal orchard: impact on seed orchards establishment

D’Amico I, Vilardi JC, Saidman BO, Ewens M, Bessega C — 2019-06-14

D’Amico I, Vilardi JC, Saidman BO, Ewens M, Bessega C

POLLEN CONTAMINATION AND MATING PATTERNS IN A PROSOPIS ALBA CLONAL ORCHARD: IMPACT ON SEED ORCHARDS ESTABLISHMENT

Abstract: Prosopis alba (Leguminosae) is an important species from ecologic and economical points of view in arid and semi-arid regions of Argentina. In several open-pollinated species, pollen contamination from off-orchard parents and selfing have been proven to reduce orchard seed quality. In 2002, the first clonal orchard of Prosopis alba was established in Fernández (Santiago del Estero, Argentina) with 12 trees phenotypically selected from a progeny trial, based on height, pod production per year and pod sweetness. The aim of this study was to evaluate the mating patterns and pollen contamination rate in the orchard using ten SSR markers and paternity analysis. All the clones together with the progeny of a single clone (open-pollinated seeds) were genotyped. Data was processed by two different methods based on likelihood and Bayesian approaches, respectively. A high consistency (89%) of results was observed between the two methods, and pollen contamination rate was estimated between 27% and 37%. The minimum number of different pollen donors per mother plant varied from three to five and selfing occurrence was low (<1.6%). Based on the estimated status number (Ns = 4.4), the expected coancestry in the seed crop is equal to a Mendelian population with an effective size of 4-5 individuals. Genetic analyses are encouraged during the establishment and monitoring of trials in forest breeding and management programmes. It is strongly recommended to establish seed orchards in isolated areas and to guarantee equal representation of parental genotypes in the orchards.

Keywords: Cervus, MasterBayes, Microsatellites, Paternity Analysis, Mesquite, Prosopis alba, Seed Orchard

iForest 12 (3): 330-337 (2019) - doi: 10.3832/ifor2936-012
https://iforest.sisef.org/contents/?id=ifor2936-012

Research Articles: Changes in forest diversity over a chronosequence of fluvial islands

Brumnich F, Marchetti ZY, Pereira MS — 2019-06-06

Brumnich F, Marchetti ZY, Pereira MS

CHANGES IN FOREST DIVERSITY OVER A CHRONOSEQUENCE OF FLUVIAL ISLANDS

Abstract: The high environmental heterogeneity of large fluvial systems is reflected by the co-existence of contrasting plant communities and landforms. The main objective of this study was to assess the forest diversity changes in islands of the Middle Paraná River (Argentina) in order to discuss an integrative question: how synchronized are the major changes in the features of islands and forests? Persistence age, elevation and flood regime of 11 main channel islands were determined. Variables related to the vascular plant community and the tree stand structure of forests were also measured in 400 m2 plots. Islands were classified as young or old (YIs or OIs), according to their persistence age, which ranged from two to 108 years. Both island classes differed in their elevation but not in the proportion of low water phase. Only three out of nine tree species were dominant: Tessaria integrifolia and Croton urucurana (restricted to YIs and OIs, respectively), and Salix humboldtiana (distributed in both island classes). Alpha diversity was positively correlated with the age of the YIs and reach the highest value in the oldest island forest. Beta diversity was mainly due to processes of species replacement which differentiate floodplain forests. Gamma diversity reached 101 species, being the perennial herbs a clear majority. The stand structure and the complete floristic composition were significantly different between YIs and OIs, with three and seven indicator species of each island class, respectively. Considering integrative models of succession, our findings suggest that the biogeomorphic phase, recognised by the fluvial biogeomorphic model, prevailed in the whole range of island persistence ages. Therefore, it seems that the increase in forest diversity in a large river is restricted to spatial refugia defined by major hydrogeomorphic shifts.

Keywords: Middle Paraná River, Fluvial Biogeomorphic Succession, Vegetation Dynamics, Environmental Heterogeneity, Sand Bars, Hydrogeomorphic Dynamics

iForest 12 (3): 306-316 (2019) - doi: 10.3832/ifor2737-012
https://iforest.sisef.org/contents/?id=ifor2737-012

Research Articles: Mechanical and physical properties of Cunninghamia lanceolata wood decayed by brown rot

Li S, Gao Y, Brunetti M, Macchioni N, Nocetti M, Palanti S — 2019-06-06

Li S, Gao Y, Brunetti M, Macchioni N, Nocetti M, Palanti S

MECHANICAL AND PHYSICAL PROPERTIES OF CUNNINGHAMIA LANCEOLATA WOOD DECAYED BY BROWN ROT

Abstract: The relationship between the mechanical properties of Cunninghamia lanceolata (Chinese fir) wood and the development of fungal decay was investigated with the aim of implementing a statistical model useful as a non-destructive and a fast method for determining the state of conservation of in-service timber structures. Artificial decay due to brown rot fungi was induced on wood specimens and physical and mechanical test were performed periodically, as well as anatomical observation of wood, FT-IR spectroscopic and XRD diffraction analysis. As a result, Chinese fir was confirmed to have a good durability against fungi, showing a mass loss percentage of 7.21% on average after 14 weeks of exposure. On the contrary, the mechanical properties reduced dramatically during the decay test: a 19% decrease was observed for compression strength and 21% for tensile strength. The mechanism of decay was explored and the corresponding damage constitutive model was proposed.

Keywords: Wooden Construction, Brown Rot, Mass Loss Rate, Wood Decay, Wood Strength

iForest 12 (3): 317-322 (2019) - doi: 10.3832/ifor2922-012
https://iforest.sisef.org/contents/?id=ifor2922-012

Research Articles: Tree-ring-based reconstruction of larch budmoth outbreaks in the Central Italian Alps since 1774 CE

Cerrato R, Cherubini P, Büntgen U, Coppola A, Salvatore MC, Baroni C — 2019-05-27

Cerrato R, Cherubini P, Büntgen U, Coppola A, Salvatore MC, Baroni C

TREE-RING-BASED RECONSTRUCTION OF LARCH BUDMOTH OUTBREAKS IN THE CENTRAL ITALIAN ALPS SINCE 1774 CE

Abstract: The larch budmoth (Zeiraphera diniana Gn. - LBM) offers a unique example of cyclic fluctuations in insect populations. During regular LBM mass outbreaks, defoliation of European larch (Larix decidua Mill.) subalpine trees results in distinct ring-width reductions in the host trees. Although several observations, reconstructions and models suggest that LBM outbreaks travel from the southwest to the northeast along the Alpine arc, gaps in the underlying data still hamper our mechanistic understanding of the spatio-temporal system dynamics. Evidence of historical LBM outbreaks before 1964 is generally associated with uncertainty and is particularly scarce for the Central Italian Alps. Here, we introduce four new larch ring-width chronologies from Val di Sole in the Central Italian Alps and use time-series analyses and comparisons with non-host trees (Picea abies Karst.) to reconstruct LBM mass outbreaks. We identify distinct fingerprints of 15 spatially-synchronized LBM events that occurred between 1774 and 1964 CE. Our results are important for improving qualitative space-time models to simulate travelling wave dynamics of insect populations, and for correcting ring-width-based summer temperature reconstructions from this part of the Alpine arc.

Keywords: European Larch, Insect Outbreaks, Larch Bud Moth, Tree-rings, Zeiraphera diniana Gn.

iForest 12 (3): 289-296 (2019) - doi: 10.3832/ifor2533-012
https://iforest.sisef.org/contents/?id=ifor2533-012

Review Papers: Should the silviculture of Aleppo pine (Pinus halepensis Mill.) stands in northern Africa be oriented towards wood or seed and cone production? Diagnosis and current potentiality

Jaouadi W, Naghmouchi S, Alsubeie M — 2019-05-27

Jaouadi W, Naghmouchi S, Alsubeie M

SHOULD THE SILVICULTURE OF ALEPPO PINE (PINUS HALEPENSIS MILL.) STANDS IN NORTHERN AFRICA BE ORIENTED TOWARDS WOOD OR SEED AND CONE PRODUCTION? DIAGNOSIS AND CURRENT POTENTIALITY

Abstract: The aim of this work is to review studies on the silviculture of Aleppo pine (Pinus halepensis Mill.) in North Africa and the Mediterranean basin over a period of 50 years. The study presents a synthesis of: (i) silviculture; (ii) wood productivity and growth; (iii) cone and seed production; and (vi) the socio-economic role of Aleppo pine. The results show that the production of the Aleppo pine is enhanced by the potential of the site, which is closely related to the bioclimatic stage and soil fertility. For instance, production increased from 0.4 to 4 m3 ha-1 yr-1 in an Aleppo pine stand with a dominant height varying between 9.7 and 22.8 m. Previous studies confirmed that the average maximum volume in annual growth of Aleppo pine is 3.3 m3 ha-1 yr-1 for 40-year old stands at good-fertility sites. The lowest values (<0.5 m3 ha-1 yr-1) were recorded for the fourth and last class of productivity in >100-year old stands. There is high demand for Aleppo pine seeds in North Africa, making their production profitable, and this represents an important sector for the sustainable development and improvement of living-standards of the local populations. There has been a steady increase in the demand for seeds across years, with seed production becoming a very promising niche. Silviculture oriented towards the commercial production of seeds is expected to enhance this species, as well as facilitate its preservation.

Keywords: Aleppo Pine, Pinus halepensis Mill., Silviculture, Wood Production, Seed Production, Socio-economic Role

iForest 12 (3): 297-305 (2019) - doi: 10.3832/ifor2965-012
https://iforest.sisef.org/contents/?id=ifor2965-012

Research Articles: Methods for predicting Sitka spruce natural regeneration presence and density in the UK

Bianchi S, Hale S, Gibbons J — 2019-05-23

Bianchi S, Hale S, Gibbons J

METHODS FOR PREDICTING SITKA SPRUCE NATURAL REGENERATION PRESENCE AND DENSITY IN THE UK

Abstract: Natural regeneration is crucial for silvicultural approaches based on the continuous presence of a forest cover, or Continuous Cover Forestry (CCF). Sitka spruce (Picea sitchensis) is the main commercial species in the United Kingdom (UK), and its potential for CCF has been demonstrated in various studies. However, there are no quantitative models available to predict its natural regeneration in the country. We describe models for Sitka spruce seedlings presence and density under canopy cover in the UK forests, to be used as a substitution of a regeneration survey. Using a natural regeneration dataset comprised of 340 plots, a Generalized Linear Mixed Model (GLMM) was calibrated to estimate the likelihood of regeneration presence at plot level. Seedling density was simulated in a subsequent step using only the subset of data with regeneration presence (138 plots): we compared methods based on GLMMs calibrated to the observed seedling density, and the simple generation of random numbers similar in distribution to the observed values. We validated the models with a cross-validation method using the calibration dataset and with an independent dataset of 78 plots collected in forests already in the process of transformation to CCF. The best GLMM for regeneration presence included age of the plantation, time after last thinning, favourable ground cover and basal area. After the cross-validation, 73% of the plots were correctly estimated (76% for presence of regeneration and 71% for the absence). After the independent validation process, 82% of the plots were correctly estimated, although 100% for presence of regeneration and only 12% for the absence. Both methods for estimating seedling density had a poor performance, both with the cross-validation and independent validation. The results showed that the tools here described are appropriate for estimating regeneration presence in traditional Sitka spruce plantations. However, alternative methods are required for forests already in an advanced stage of transformation to CCF systems.

Keywords: Sitka Spruce, Natural Regeneration, Regeneration Occurrence, Logistic Modelling, Seedling Density

iForest 12 (3): 279-288 (2019) - doi: 10.3832/ifor2888-012
https://iforest.sisef.org/contents/?id=ifor2888-012

Research Articles: Tree aging does not affect the ranking for water use efficiency recorded from δ13C in three Populus deltoides × P. nigra genotypes

Rasheed F, Dreyer E, Le Thiec D, Zafar Z, Delagrange S — 2019-05-21

Rasheed F, Dreyer E, Le Thiec D, Zafar Z, Delagrange S

TREE AGING DOES NOT AFFECT THE RANKING FOR WATER USE EFFICIENCY RECORDED FROM δ13C IN THREE POPULUS DELTOIDES × P. NIGRA GENOTYPES

Abstract: A large variability of water use efficiency (assessed from the carbon isotopic discrimination in leaves and leaf soluble sugars) has been detected among poplar genotypes. Checking whether such differences detected in young trees (1-2 years old) remain stable with tree age is a prerequisite to use this trait with confidence for breeding purposes. In this study, a synchronic approach was used to test the age-related stability of the genotypic ranking of carbon isotopic discrimination in wood (Δ13C) until tree maturity. We sampled 376 trees between 4 and 20 years from three Populus deltoides × P. nigra genotypes growing in 41 common-garden trials across France. Carbon and nitrogen percentages along with δ13C was measured in the bulk wood of the year 2009 and used to compute the Δ13C. Basal area increment between 2008 and 2009 was also measured. Results showed that Δ13C increased (i.e., water use efficiency decreased) between ages 4 to 6 and remained stable later on. Significant differences among genotypes were found but the ranking among genotypes remained stable with age during the assessed life span. Furthermore, basal area increment and Δ13C were positively correlated interannually. This large-scale survey shows that despite crossing over in the temporal trend, water use efficiency remained stable with age across 3 poplar genotypes. However, further studies with a large number of genotypes are required to confirm whether this trait can be used to maintain or even improve productivity of poplar plantations, while lowering water consumption.

Keywords: Water Use Efficiency, Age, Wood, Tree Ring, Populus × euramericana, Basal Area Increment, Synchronic Approach

iForest 12 (3): 272-278 (2019) - doi: 10.3832/ifor2896-012
https://iforest.sisef.org/contents/?id=ifor2896-012

Research Articles: Species-specific responses of wood growth to flooding and climate in floodplain forests in Central Germany

Heklau H, Jetschke G, Bruelheide H, Seidler G, Haider S — 2019-05-03

Heklau H, Jetschke G, Bruelheide H, Seidler G, Haider S

SPECIES-SPECIFIC RESPONSES OF WOOD GROWTH TO FLOODING AND CLIMATE IN FLOODPLAIN FORESTS IN CENTRAL GERMANY

Abstract: With ongoing climate change, episodes of severe flooding are predicted to become more frequent despite a general trend towards increasing summer drought. We investigated how wood growth of adult trees of two species characteristic of floodplain forests in Central Germany (Fraxinus excelsior L., Quercus robur L.) and two less-typical species (Acer pseudoplatanus L., Carpinus betulus L.) responded to both maximum stream water level and climate, with a special focus on the effects of the extraordinary flood of the Saale River in June 2013 and the extreme drought in summer 1976. Tree-ring widths were measured on wood cores, and standardized ARSTAN tree-ring chronologies were produced. Using variance partitioning as well as linear mixed-effects models, we compared the effects of monthly values for maximum water level, temperature and precipitation sum on tree-ring width. Further, we calculated resistance, resilience and recovery of the tree species to the extreme events of flooding in 2013 and drought in 1976. Wood growth of all species studied, and particularly of F. excelsior, responded positively to the extraordinary flooding in June 2013. However, in the best models for the characteristic floodplain forest species (F. excelsior and Q. robur), mainly precipitation (F. excelsior) or a combination of precipitation and wood growth of the previous year (Q. robur) acted as drivers of wood growth of the current year. In contrast, growth of the less habitat-specific species (A. pseudoplatanus) mainly showed a significant response to the combination of temperature and wood growth of the previous year. C. betulus was the only species studied that benefited from the extreme drought in 1976. However, two years afterwards, only the wood growth of A. pseudoplatanus was still reduced, while F. excelsior and Q. robur fully recovered. In comparison to other regions in Central Europe, the moderate flood regime of the Saale River seems to have the potential to mitigate effects of summer drought in this region, which is one of the driest in Germany. Thus, increased flooding frequency might, to some degree, reduce drought effects brought about by climate change as well.

Keywords: Tree-ring Width, Floodplain Forest, Flooding, Drought, Dendroecology, Fraxinus excelsior, Quercus robur, Acer pseudoplatanus

iForest 12 (3): 226-236 (2019) - doi: 10.3832/ifor2845-012
https://iforest.sisef.org/contents/?id=ifor2845-012

Research Articles: Using soil-based and physiographic variables to improve stand growth equations in Uruguayan forest plantations

Rachid-Casnati C, Mason EG, Woollons RC — 2019-05-03

Rachid-Casnati C, Mason EG, Woollons RC

USING SOIL-BASED AND PHYSIOGRAPHIC VARIABLES TO IMPROVE STAND GROWTH EQUATIONS IN URUGUAYAN FOREST PLANTATIONS

Abstract: Information provided by traditional growth models is an essential input in decision making processes for managing planted forests. They are generally fitted using inventory data guaranteeing robustness and simplicity. The introduction of explanatory factors affecting tree development in age-based sigmoidal growth and yield equations attempts not only to improve the quality of predictions, but also to add useful information underpinning forest management decisions. This study aimed to assess the use of the following soil-based and physiographic predictors: potentially available soil water (PASW), elevation (Elev), aspect (α) and slope (β) in a system of empirical stand equations comprising: dominant height (hdom), basal area (G), maximum diameter at breast height (dmax), and standard deviation of diameters (SDd). Augmented models were compared with the base models through precision and bias of estimations for two contrasting species: Pinus taeda (L.), and Eucalyptus grandis (Hill ex. Maiden), planted commercially in Uruguay. Soil-based and physiographic information significantly improved predictions of all the state variables fitted for E. grandis, but just hdom and G for P. taeda. Only PASW was consistently significant for the augmented models in P. taeda and E. grandis, while the contribution of other predictors varied between species. From a physiological point of view, predictors on the augmented models showed consistency. Models with such augmentation produced decrease of errors between 3 to 10.5%, however decreases in the prediction errors calculated with the independent dataset were lower. Results from this study contributed to add information to the decision-making process of plantations’ management.

Keywords: Forest Modelling, Soil Variables, Physiographic Variables, Pinus taeda, Eucalyptus grandis

iForest 12 (3): 237-245 (2019) - doi: 10.3832/ifor2926-012
https://iforest.sisef.org/contents/?id=ifor2926-012

Research Articles: Disentangling the effects of age and global change on Douglas fir growth

Ravaioli D, Ferretti F, Magnani F — 2019-05-03

Ravaioli D, Ferretti F, Magnani F

DISENTANGLING THE EFFECTS OF AGE AND GLOBAL CHANGE ON DOUGLAS FIR GROWTH

Abstract: Recent changes commonly observed in forests growth could be the result of a combination of different climatic and non-climatic factors, such as rising atmospheric [CO2], temperature changes, atmospheric N deposition and drought stress. These effects are difficult to assess, however, due to the superimposition of age-related changes. After removing age effects through a novel approach, this study quantifies the effects on tree growth of global change, and assesses the relationship with individual environmental drivers and their relative importance. Generalized Additive Mixed Models (GAMMs) were applied to decouple the non-linear effects of age and co-occurring environmental changes on basal area increments (BAI) series, as derived from tree rings in a Pseudotsuga menziesii stand chronosequence of four different age classes (65-, 80-, 100- and 120-year-old). The model could explain about 57% of the overall variation in BAI as a function of age and a selected set of predictors, including water availability in the current summer and at the end of previous growing season; together with age, winter-spring mean temperature was found to be the most important predictor. After accounting for age-related effects, a significant decrease in BAI was observed in Douglas fir over the last decades. No significant impact of atmospheric [CO2] and atmospheric N deposition were detected.

Keywords: Pseudotsuga menziesii, Basal Area Increments, Long-term Trends, Global Change, GAMM, Chronosequence

iForest 12 (3): 246-253 (2019) - doi: 10.3832/ifor2620-012
https://iforest.sisef.org/contents/?id=ifor2620-012

Research Articles: Responses of Taxus chinensis and Phoebe chekiangensis seedlings to controlled-release fertilizer in various formulations and application rates

Chu X, Wang X, Zhang D, Wu X, Zhou Z — 2019-05-03

Chu X, Wang X, Zhang D, Wu X, Zhou Z

RESPONSES OF TAXUS CHINENSIS AND PHOEBE CHEKIANGENSIS SEEDLINGS TO CONTROLLED-RELEASE FERTILIZER IN VARIOUS FORMULATIONS AND APPLICATION RATES

Abstract: Decline of species population, low natural regeneration, and heavy competition on field sites require the planting of large seedling stocks to restore Taxus chinensis and Phoebe chekiangensis in tropical China. In this study, we examined the effects of different formulations and application rates of controlled-release fertilizers (CRF) of nitrogen (N) and phosphorus (P) on nursery seedling growth and nutritional attributes. The objective was to determine optimum formulation (N:P2O5 ratio) and application rate to increase nutrient reserves of the seedlings before transplanting to the field. Four formulations (17-9-13 to 19-6-14 N-P2O5-K2O ratios) and four application rates (1.5 kg m-3 to 4.5 kg m-3) were used in a double-factors factorial design with 3 replications. The results showed that CRF formulation can affect nutritional attributes, while application rate modified seedling growth and nutritional attributes. The optimum seedling response occurred with the 17-6-16 formulation at the rate of 3.5kg m-3. These findings will guide nursery practice in the production of high-quality seedlings for optimum survival and growth in the field.

Keywords: Taxus chinensis, Phoebe chekiangensis, Controlled-Release Fertilizer, Formulation and Application Rate, Nutrient Utilization Efficiency

iForest 12 (3): 254-261 (2019) - doi: 10.3832/ifor2714-012
https://iforest.sisef.org/contents/?id=ifor2714-012

Research Articles: Diurnal surface fuel moisture prediction model for Calabrian pine stands in Turkey

Bilgili E, Coskuner KA, Usta Y, Saglam B, Kucuk O, Berber T, Goltas M — 2019-05-03

Bilgili E, Coskuner KA, Usta Y, Saglam B, Kucuk O, Berber T, Goltas M

DIURNAL SURFACE FUEL MOISTURE PREDICTION MODEL FOR CALABRIAN PINE STANDS IN TURKEY

Abstract: This study presents a dynamic model for the prediction of diurnal changes in the moisture content of dead surface fuels in normally stocked Calabrian pine stands under varying weather conditions. The model was developed based on several empirical relationships between moisture contents of dead surface fuels and weather variables, and calibrated using field data collected from three Calabrian stands from three different regions of Turkey (Mugla, southwest; Antalya, south; Trabzon, north-east). The model was tested and validated with independent measurements of fuel moisture from two sets of field observations made during dry and rainy periods. Model predictions showed a mean absolute error (MAE) of 1.19% for litter and 0.90% for duff at Mugla, and 3.62% for litter and 14.38% for duff at Antalya. When two rainy periods were excluded from the analysis at Antalya site, the MAE decreased from 14.38% to 4.29% and R2 increased from 0.25 to 0.83 for duff fuels. Graphical inspection and statistical validation of the model indicated that the diurnal litter and duff moisture dynamics could be predicted reasonably. The model can easily be adapted for other similar fuel types in the Mediterranean region.

Keywords: Fuel Moisture Content, Modeling, Drying Rate, Vapor Pressure Deficit

iForest 12 (3): 262-271 (2019) - doi: 10.3832/ifor2870-012
https://iforest.sisef.org/contents/?id=ifor2870-012

Research Articles: Estimation of forest biomass components using airborne LiDAR and multispectral sensors

2019-04-25

Hernando A, Puerto L, Mola-Yudego B, Manzanera JA, García-Abril A, Maltamo M, Valbuena R

ESTIMATION OF FOREST BIOMASS COMPONENTS USING AIRBORNE LIDAR AND MULTISPECTRAL SENSORS

Abstract: In order to consider forest biomass as a real alternative for energy production, it is critical to obtain accurate estimates of its availability using non-destructive sampling methods. In this study, we estimate the biomass available in a Scots pine-dominated forest (Pinus sylvestris L.) located in Spain. The biomass estimates were obtained using LiDAR data combined with a multispectral camera and allometric equations. The method used to fuse the data was based on back projection, which assures a perfect match between both datasets. The results present estimates for each of the seven different biomass components: above ground, below ground, log, needles, and large, medium and small branches. The accuracy of the models varied between R2 values of 0.46 and 0.67 with RMSE% ranging from 15.72% to 35.43% with all component estimates below 20%, except for the model estimating biomass of big branches. The models in this study are suitable for the estimation of biomass and demonstrate that computation is possible at a fine scale for the different biomass components. These remote sensing methods are sufficiently accurate to develop biomass resource cartography for multiple energy uses.

Keywords: Biomass Components, Forest Inventory, Airborne Laser Scanning, Multispectral Imagery, Data Fusion, Nearest Neighbor

iForest 12 (2): 207-213 (2019) - doi: 10.3832/ifor2735-012
https://iforest.sisef.org/contents/?id=ifor2735-012

Research Articles: Genetic control of intra-annual height growth in 6-year-old Norway spruce progenies in Latvia

Matisons R, Zeltinš P, Danusevičius D, Džerina B, Desaine I, Jansons A — 2019-04-25

Matisons R, Zeltinš P, Danusevičius D, Džerina B, Desaine I, Jansons A

GENETIC CONTROL OF INTRA-ANNUAL HEIGHT GROWTH IN 6-YEAR-OLD NORWAY SPRUCE PROGENIES IN LATVIA

Abstract: Coupling growth with periods of favourable weather conditions minimizes risks of frost damage and maximizes annual height increment. The phenology of the formation of height increment is therefore a trait related to the adaptability of trees to annual weather fluctuations. Strong genetic control of the timing of the onset and cessation of shoot elongation has been reported for Norway spruce, but little is known about its fluctuations that occur during the growth period. The strength of the genetic control of the height growth rate was assessed for young (6 years old) Norway spruce progenies originating from six open-pollinated stands from two local provenance regions. In 2010, the length of the growing period for the studied trees was ca. 60 days. Trees from the more continental provenance region, which had later onset and cessation of height growth (by ca. 2.5 days), exhibited slightly lower increments (by ca. 1%). Accordingly, the provenance region had a significant effect on height growth at the beginning and end of the growing period. Nevertheless, considerable genetic control of the growth rate was found throughout the entire growing period (particularly at the beginning and cessation, ha2 ≥ 0.20), except for a week-long interval around mid-summer (ha2 = 0.07). Similarly, the coefficient of additive genetic variation suggested that breeding could be applied for the improvement of height growth intensity throughout the season. The phenotypic correlations between weekly growth rates and tree height (before growth) were mostly non-significant, suggesting varying mechanisms of control, hence possibility for simultaneous improvement of the traits by breeding.

Keywords: Height Growth Rate, Growing Period, Heritability, Picea abies, Local Populations

iForest 12 (2): 214-219 (2019) - doi: 10.3832/ifor2777-012
https://iforest.sisef.org/contents/?id=ifor2777-012

Research Articles: Matching seedling size to planting conditions: interactive response with soil moisture

Oliet JA, Ortiz de Urbina E, Sánchez-Pinillos M, Tardío-Cerrillo G — 2019-04-25

Oliet JA, Ortiz de Urbina E, Sánchez-Pinillos M, Tardío-Cerrillo G

MATCHING SEEDLING SIZE TO PLANTING CONDITIONS: INTERACTIVE RESPONSE WITH SOIL MOISTURE

Abstract: Seedling size is a very important issue when producing plants for restoration projects. Scientific evidence on the appropriate size for drylands is contradictory. Thus, the aim of this study was to evaluate the effect of seedling size during first establishment by conducting a short term greenhouse experiment with Pinus canariensis containerized seedlings. A selection of large (mean height: 33.7 cm) and small (14.3 cm) one-year-old seedlings were planted in pots under two volumetric water content regimes: dry (7%) and wet (15%). Midday shoot water potential was measured in two periods: 10 (prior to root protrusion) and 30 (once the roots had protruded from the plug) days after planting. The length of protruding roots was measured after 30 days. One month after planting, the large seedlings under the dry regime produced more new roots than the small seedlings, but also showed the highest midday water potential values. Therefore, the greater root growth of the former did not offset the higher transpiration demand when planted in dry soils. These results suggest that under uncertainty about the soil humidity levels of dry areas, using small seedlings can improve their short-term survival after planting.

Keywords: Planting Survival, Root Water Uptake, Seedling Size, Seedling Ecophysiology, Transpiration Demand, Water Potential, Seedling Morphology

iForest 12 (2): 220-225 (2019) - doi: 10.3832/ifor2801-012
https://iforest.sisef.org/contents/?id=ifor2801-012

Research Articles: The manipulation of aboveground litter input affects soil CO2 efflux in a subtropical liquidambar forest in China

Yan W, Peng Y, Zhang C, Chen X — 2019-04-10

Yan W, Peng Y, Zhang C, Chen X

THE MANIPULATION OF ABOVEGROUND LITTER INPUT AFFECTS SOIL CO2 EFFLUX IN A SUBTROPICAL LIQUIDAMBAR FOREST IN CHINA

Abstract: Litters on the forest floor represent an important organic carbon (C) sources from aboveground plants to the soil, which therefore have a significant influence on belowground processes such as soil respiration. In this study, dynamic property of soil respiration was investigated under aboveground litter manipulation treatments in a liquidambar forest in subtropical China. The purpose of this study was to examine the impacts of changing aboveground litter inputs on soil CO2 emission in forests. The litter manipulation included litter addition (LA), litter removal (LR) and litter control (LC) treatments. Each litter treatment had six replications. Soil respiration rates were measured using an infrared gas analyzer system (LI-COR 8100) with soil chambers. The results showed that mean soil respiration rates increased significantly in LA plots (mean ± SE: 2.21 ± 0.44 μmol m-2 s-1; P<0.05) and decreased slightly in LR plots (1.17 ± 0.16 μmol m-2 s-1) when compared to control plots (1.42 ± 0.20 μmol m-2 s-1). On average, LA treatment significantly increased annual soil respiration by about 56% (837.5 ± 165 gC m-2 year-1), while LR treatment decreased soil respiration by approximately 17% (443.1 ± 61.7 gC m-2 year-1) compared with the control (535.5 ± 75.7 gC m-2 year-1). The “priming effect” was a primary contributor to the increase of soil respiration in LA treatments and the reduction of soil CO2 efflux was mainly ascribed to the elimination of organic C sources in LR treatments. Soil temperature was the main factor affecting seasonal variation in soil respiration. Up to the 90% to 95% seasonal variation in soil respiration is explained by soil temperature within each of the litter treatments. Our study indicated that changes in litter inputs due to climate change and human practices would significantly affected soil CO2 emission and would subsequently affect C balance in subtropical forests.

Keywords: Soil CO2 Emission, Annual Litter Input, Deciduous Forests, Soil Temperature, Soil Water Contents, Subtropical China

iForest 12 (2): 181-186 (2019) - doi: 10.3832/ifor2812-012
https://iforest.sisef.org/contents/?id=ifor2812-012

Research Articles: Retaining unlogged patches in Mediterranean oak forests may preserve threatened forest macrolichens

2019-04-10

Fačkovcová Z, Guttová A, Benesperi R, Loppi S, Bellini E, Sanità di Toppi L, Paoli L

RETAINING UNLOGGED PATCHES IN MEDITERRANEAN OAK FORESTS MAY PRESERVE THREATENED FOREST MACROLICHENS

Abstract: Forest management practices may heavily impact epiphytic (tree inhabiting) organisms. Retaining tree patches and buffer strips in logged stands may contribute to preserve ecosystem functioning and the vitality of epiphytic organisms in managed forests. To test these statements, the threatened forest macrolichen Lobaria pulmonaria (L.) Hoffm. was used as a model species, since it is a “flag” indicator species of forest ecosystems with long ecological continuity. To this purpose, photosynthetic performances, thallus anatomy and water holding capacity (WHC) of samples of L. pulmonaria were investigated in a logged mixed oak forest (Tuscany, Italy), confronting lichen thalli from retained-forest patches and retained-isolated trees, 18 months after logging. Compared with those of retained-forest patches, thalli on the trunks of retained-isolated trees were thinner and showed lower vitality (as indicated by the potential quantum yield of primary photochemistry - FV/FM and the index of overall photosynthetic performance - PIABS), as well as lower water holding capacity. In contrast, thalli from forest patches had performances comparable to those of healthy samples from unlogged forests.

Keywords: Biodiversity Conservation, Ecosystem Services, Forest Logging, Lobaria pulmonaria, Photosynthetic Performance, Water Holding Capacity

iForest 12 (2): 187-192 (2019) - doi: 10.3832/ifor2917-012
https://iforest.sisef.org/contents/?id=ifor2917-012

Short Communications: Detection and quantification of the air inoculum of Caliciopsis pinea in a plantation of Pinus radiata in Italy

2019-04-10

Botella L, Bačová A, Dvorák M, Kudláček T, Pepori AL, Santini A, Ghelardini L, Luchi N

DETECTION AND QUANTIFICATION OF THE AIR INOCULUM OF CALICIOPSIS PINEA IN A PLANTATION OF PINUS RADIATA IN ITALY

Abstract: Caliciopsis pinea has been historically described as a secondary pathogen of pines. However, it has recently been associated with severe damages on Pinus radiata in Italy. Our study focused on the description of the seasonal spore dispersal of C. pinea and its relation to meteorological conditions (temperature, leaf wetness, relative humidity and precipitations). For this experiment one infected P. radiata plantation was sampled in Tuscany (Italy). A rotating arm spore trap together with a weather station were installed to sample the aerospora for 24 h every week from May to November 2016. Exposed tapes from spore traps were directly analyzed after DNA extraction by qPCR using specific primers and TaqMan MGB probe. The study shows an irregular occurrence of the inoculum of C. pinea throughout the whole sampling period with peak levels in mid-June and early August. The statistical analysis of the DNA and climatic data clearly show the strong influence of precipitation on the spore production of this pathogen. Furthermore, the very low detection limit of the qPCR experiment shows the efficacy and suitability of rotating arm spore traps for early detection of this pathogen.

Keywords: Caliciopsis Canker, Monterey Pine, Aerospora, qPCR

iForest 12 (2): 193-198 (2019) - doi: 10.3832/ifor2866-012
https://iforest.sisef.org/contents/?id=ifor2866-012

Research Articles: Dielectric properties of paraffin wax emulsion/copper azole compound system treated wood

Liao Y, Ma E, Liu R — 2019-04-10

Liao Y, Ma E, Liu R

DIELECTRIC PROPERTIES OF PARAFFIN WAX EMULSION/COPPER AZOLE COMPOUND SYSTEM TREATED WOOD

Abstract: In order to investigate the interactions among the waterproof agent, preservative and wood, the dielectric relaxation was measured for untreated wood and wood samples treated with different paraffin wax emulsion/copper azole (CA) compound systems at oven-dried and air-dried state, respectively. The Cole-Cole plot analysis was then conducted and the results were as follow. At oven-dried state (-60 °C), the dielectric characteristics of paraffin wax emulsion treated wood were basically the same as those of untreated wood; CA treatment increased the dielectric constant but decreased the dielectric loss factor and the trends of these two characteristic parameters were more remarkable at higher CA concentration; the dielectric properties of compound system treated wood under C4A grade were similar to those of CA treated wood but an increase in impregnation of paraffin wax emulsion gave rise to decreased dielectric constant and increased loss factor. At air-dried state (20 °C, 65% RH), compared with untreated samples, both the dielectric constant and loss factor were lower in waterproofing agent treated wood and these parameters reduced with increasing waterproofing agent concentration; for CA treated samples, the values of dielectric parameters increased and the trend was similar to those treated with the compound system under C4A grade.

Keywords: Wood, Paraffin Wax Emulsion, Copper Azole, Dielectric Properties

iForest 12 (2): 199-206 (2019) - doi: 10.3832/ifor2879-012
https://iforest.sisef.org/contents/?id=ifor2879-012

Research Articles: Equations for estimating belowground biomass of Silver Birch, Oak and Scots Pine in Germany

Röhling S, Demant B, Dunger K, Neubauer M, Oehmichen K, Riedel T, Stümer W — 2019-03-15

Röhling S, Demant B, Dunger K, Neubauer M, Oehmichen K, Riedel T, Stümer W

EQUATIONS FOR ESTIMATING BELOWGROUND BIOMASS OF SILVER BIRCH, OAK AND SCOTS PINE IN GERMANY

Abstract: In this study we derived allometric functions for estimating the belowground biomass (BGB) of Silver Birch (Betula pendula Roth), Pedunculate Oak (Quercus robur L.), Sessile Oak (Quercus petraea (Matt.) Liebl.) and Scots Pine (Pinus sylvestris L.) in Germany. To assess the impact on German greenhouse gas (GHG) reporting, these new functions were further compared with BGB functions currently used in France and Sweden. For developing new BGB functions 48 Silver Birches, 39 Pedunculate and Sessile Oaks and 54 Scots Pines were destructively sampled. The sampled trees spanned a DBH range from 8.2 to 52.9 cm for Silver Birch, from 7.4 to 42.0 cm for Oak and from 7.2 to 53.2 cm for Scots Pine. After fitting the data, the following values of model efficiency were achieved: 0.81 for Silver Birch, 0.98 for Oak and 0.95 for Scots Pine. The model root mean square error varies between 5.2 kg for Oak, 13.7 kg for Scots pine and 26.9 kg for Silver Birch. Comparison with the currently applied BGB functions in the German GHG inventory from France and Sweden showed that the use of these functions results in systematically different estimates for the BGB of Silver Birch and Oak. Thus, our findings indicate that BGB functions recommended for other European countries (in particular France and Sweden) are not appropriate for estimating the BGB for the tree species concerned in Germany. Currently, the derived data-set for BGB of Silver Birch, Oak and Scots Pine is the largest in Germany and the developed functions are thus the best available for estimating national BGB stock and stock change in Germany at the moment.

Keywords: Belowground Biomass, Allometric Equations, National Greenhouse Gas Inventory, Betula pendula, Quercus robur, Quercus petraea, Pinus sylvestris

iForest 12 (2): 166-172 (2019) - doi: 10.3832/ifor2862-012
https://iforest.sisef.org/contents/?id=ifor2862-012

Research Articles: Reviewing climatic traits for the main forest tree species in Italy

2019-03-15

Pecchi M, Marchi M, Giannetti F, Bernetti I, Bindi M, Moriondo M, Maselli F, Fibbi L, Corona P, Travaglini D, Chirici G

REVIEWING CLIMATIC TRAITS FOR THE MAIN FOREST TREE SPECIES IN ITALY

Abstract: The future dynamics of forest species and ecosystems depend on the effects of climate change and are related to forest management strategies. The expected impacts of climate change are linked to forest growth and productivity. An increase in the length of the growing season and greater productivity are likely as well as shifts in average climatic values and more variable frequencies, intensities, durations and timings of extreme events. The main aim of this work is to assess and describe the climatic requirements for Italian forest tree species. We used 7,272 field observations from Italian National Forest Inventory plots and average annual temperatures and precipitation as interpolated from raster maps with 1 km spatial resolution. On this basis we evaluated the current observed distributions of the 19 most important tree species in Italy with respect to potential climatic limits based on expert knowledge and the available literature. We found that only 46% of the observations fall within the potential joint temperature and precipitation limits as defined by expert knowledge. For precipitation alone, 70% of observations were within the potential limits, and for temperature alone, 80% of observations were within the potential limits. Similarity between current observed and potential limits differ from species-to-species with broadleaves in general more frequently distributed within the potential climatic limits than conifers. We found that ecological requirements and potential information should be revised for some species, particularly for the Pinus genus and more frequently for precipitation. The results of the study are particularly relevant given the threat of climate change effects for Italian forests which are broadly acknowledged to be a biodiversity hotspot. Further investigations should be aimed at modelling the effects of climate changes on Italian forests as a basis for development of mitigation and adaptation forest management strategies.

Keywords: National Forest Inventory, Sustainable Forest Management, Spatial Analysis, Forest Monitoring, Climatic Drivers

iForest 12 (2): 173-180 (2019) - doi: 10.3832/ifor2835-012
https://iforest.sisef.org/contents/?id=ifor2835-012

Research Articles: Hemlock woolly adelgid niche models from the invasive eastern North American range with projections to native ranges and future climates

2019-03-04

Kantola T, Tracy JL, Lyytikäinen-Saarenmaa P, Saarenmaa H, Coulson RN, Trabucco A, Holopainen M

HEMLOCK WOOLLY ADELGID NICHE MODELS FROM THE INVASIVE EASTERN NORTH AMERICAN RANGE WITH PROJECTIONS TO NATIVE RANGES AND FUTURE CLIMATES

Abstract: The hemlock woolly adelgid (Adelges tsugae Annand - HWA) is invasive in eastern North America where it causes extensive mortality to hemlock communities. The future of these communities under projected climate change is an issue of landscape ecological interest and speculation. We employed the MaxEnt algorithm with the random subset feature selection algorithm (RSFSA) in creating HWA niche models. Final models were ensembles of 12 statistically best models with six predictors each. Out of 119 climatic, topographic, and soil variables, 42 were used in at least one final model. Soil features, followed by climate and topographic features, were most common in selected models. The three most important variables among all models were November potential evapotranspiration, slope, and percent Ochrepts soil. The potential distributions of HWA within eastern North America were projected under historical and four future climate scenarios for 2050 and 2070 under low and high CO2 emissions. The mean of the minimum values for the minimum temperature of the coldest month from the 12 MaxEnt model projections in eastern North America was -15.8°C. This value was close to -15°C, the extreme minimum temperature found for both HWA occurrence points and previously reported HWA cold temperature limits. These results indicate that HWA may be close to equilibrium distribution in eastern North America under current climate. We also reverse-casted the eastern North American MaxEnt model back onto the HWA native ranges in eastern Asia and western North America. The projections match best with native ranges in Asian islands, such as Japan, and the Cascade Mountains in western North America. Statistically significant HWA range shifts of 221-468 km northwards and 110-164 km eastwards were projected by the 12 models for 2050-2070. The 2070 high CO2 emission scenario models projects HWA suitability throughout most of the northern range of eastern hemlock.

Keywords: Ecological Niche Modeling, Climate Change, Hemlock Woolly Adelgid, Invasive Species, MaxEnt, Feature Selection

iForest 12 (2): 149-159 (2019) - doi: 10.3832/ifor2883-012
https://iforest.sisef.org/contents/?id=ifor2883-012

Research Articles: Lenticel infection in Fraxinus excelsior shoots in the context of ash dieback

Nemesio-Gorriz M, McGuinness B, Grant J, Dowd L, Douglas GC — 2019-03-04

Nemesio-Gorriz M, McGuinness B, Grant J, Dowd L, Douglas GC

LENTICEL INFECTION IN FRAXINUS EXCELSIOR SHOOTS IN THE CONTEXT OF ASH DIEBACK

Abstract: Common ash (Faxinus excelsior L.) in Europe is declining on a continental scale due to the action of Hymenoscyphus fraxineus, an invasive forest pathogen that causes ash dieback disease leading to the collapse and eventual death of ash trees through shoot infection in the crown and through stem collar infection. This study confirms for the first time lenticels as entry points for pathogens to enter shoot bark. Results show the impact of lenticel infection at a very early stage of invasion by H. fraxineus in a F. excelsior provenance trial and its correlation values with other factors such as shoot dieback, canker-like lesions and bud burst. No significant provenance effects were observed for incidence of shoot dieback, lenticel necrosis or canker-like lesions on shoots, but provenance effects were significant for bud burst phenology. The strongest correlation was observed between lenticel necrosis and canker-like lesions on the lenticels of shoots. Boheremia spp. were most frequently isolated from necrotic ash lenticels and confirmed by ITS sequencing, but also species of Diaporthe, Epicoccum, Aspergillus, Neonectria, Didymella and Hymenoscyphus fraxineus. Finally, lenticel density was similar in sets of ash genotypes that were characterized as having a high and low susceptibility to ash dieback.

Keywords: Ash Dieback, Lenticel, ADB, Phenology

iForest 12 (2): 160-165 (2019) - doi: 10.3832/ifor2897-012
https://iforest.sisef.org/contents/?id=ifor2897-012

Research Articles: Allelopathic effects of dominant ground vegetation species on initial growth of Pinus sylvestris L. seedlings in response to different temperature scenarios

2019-02-27

Sirgedaite-Šežiene V, Baležentiene L, Varnagiryte-Kabašinskiene I, Stakenas V, Baliuckas V

ALLELOPATHIC EFFECTS OF DOMINANT GROUND VEGETATION SPECIES ON INITIAL GROWTH OF PINUS SYLVESTRIS L. SEEDLINGS IN RESPONSE TO DIFFERENT TEMPERATURE SCENARIOS

Abstract: The dominant species of ground vegetation cover in clear-cuts impact the regeneration of Scots pine forests due to the biochemical properties of these dominant species. Environmental conditions in clear-cuts, specifically increased light and temperature, can alter the biochemical impact of dominant species on subsequent Scots pine regeneration processes. To investigate this, plant species diversity, frequency and cover were estimated in order to identify the dominant species of ground vegetation in clear-cut areas over a two-year period. Afterward, the impact of dominant species extracts on pine seed germination and seedling physiology at different temperature scenarios was evaluated. The species Pleurozium schreberi (Brid.) Mitt., Vaccinium vitis-idaea L. and Calluna vulgaris (L.) Hull were recorded as dominant in 1-yr-old clear-cut areas, and Vaccinium vitis-idaea L., Rumex acetosella L., and Calamagrostis epigejos (L.) Roth were dominant in 2-yr-old clear-cut areas. The prepared aqueous extracts of all dominant species exhibited strong inhibitory effects on pine seed germination and seedling morpho-physiological traits (the length of the radicle and hypocotyl; chlorophyll a, b, a/b and carotenoid content), resulting in the reduction of ex situ pine adaptive capacity at higher air temperature (24°C) compared to that at lower temperature (20°C). Significantly (p<0.05) stronger inhibitory effects of root and shoot extracts produced from all dominant species on chlorophyll a, b and a/b content were recorded at higher temperature (22-24°C) compared to lower (20°C) temperature. A significantly lower content of carotenoids was observed in the control (24°C) temperature. Thus, a high increase of ambient temperature may cause unfavourable conditions for Scots pine seedling growth in boreal forests.

Keywords: Carotenoids, Chlorophylls, Clear-cut, Germination, Plant Extract

iForest 12 (1): 132-140 (2019) - doi: 10.3832/ifor2904-012
https://iforest.sisef.org/contents/?id=ifor2904-012

Research Articles: Influence of pH, nitrogen and sulphur deposition on species composition of lowland and montane coniferous communities in the Tatrzanski and Slowinski National Parks, Poland

Uzieblo AK, Staszewski T, Chmura D — 2019-02-27

Uzieblo AK, Staszewski T, Chmura D

INFLUENCE OF PH, NITROGEN AND SULPHUR DEPOSITION ON SPECIES COMPOSITION OF LOWLAND AND MONTANE CONIFEROUS COMMUNITIES IN THE TATRZANSKI AND SLOWINSKI NATIONAL PARKS, POLAND

Abstract: Nitrogen and sulphur deposition is considered as a negative factor for biodiversity, usually leading to changes in species composition and structure of plant communities, and ultimately to the impoverishment of biodiversity. In this study we investigated the variation over time (2001, 2006, 2011) in species composition and structure of the understory vegetation at varying levels of sulphur and nitrogen deposition in two conifer plantations (>100 year-old) growing in different climate areas of Poland (Scots pine at the Slowinski National Park, northern seaside; Norway spruce at the Tatrzanski National Park, southern mountains). The structure of the floor vegetation at both sites changed markedly during the studied decade, as clearly confirmed by principal component analysis. Among the environmental variables analyzed (NH4+, NO3-, SO42-, pH in the throughfall and in soil solution sampled at two different depths), only nitrates were non-significantly correlated with PC axes. The results confirmed the negative effects of the concentration of both elements on undergrowth and tree recruitment in the coastal stand (Empetro nigri-Pinetum). On the other hand, in the mountain stand (Abieti-Piceetum) we observed an increase over time of nitrophilous species typical of the beech forest, which represent the natural vegetation of this area, suggesting a gradual natural restoration of the native vegetation in the long run.

Keywords: Nitrogen Deposition, Sulphur Deposition, Climatic Changes, Coniferous Communities, Biodiversity

iForest 12 (1): 141-148 (2019) - doi: 10.3832/ifor2203-012
https://iforest.sisef.org/contents/?id=ifor2203-012

Research Articles: Big data and evaluation of cultural ecosystem services: an analysis based on geotagged photographs from social media in Tuscan forest (Italy)

Bernetti I, Chirici G, Sacchelli S — 2019-02-11

Bernetti I, Chirici G, Sacchelli S

BIG DATA AND EVALUATION OF CULTURAL ECOSYSTEM SERVICES: AN ANALYSIS BASED ON GEOTAGGED PHOTOGRAPHS FROM SOCIAL MEDIA IN TUSCAN FOREST (ITALY)

Abstract: The paper presents a methodology to quantify the suitability of forest stands for the potential delivery of cultural ecosystem services (CES). The quantification of CES represents a complicated task in the framework of ecosystem service valuation. Compared to traditional investigations, focusing on the study of the aesthetic appreciation of a particular territory, the use of geotagged photographs seems to be a promising alternative to appraise CES. Thus, in order to analyse CES with a particular focus on the aesthetic appreciation of forest stands, this study exploits big data through the analysis of photos shared on the Flickr social network. Crowdsourced datasets are used to depict the geographic location and density of pictures - expressed as the number of photos per unit of surface - as well as their relationship to forest variables and logistic characteristics. The implemented geostatistical model is used to spatialise the results at the regional level (Tuscany forests, Italy). Among the outputs, high values of CES are stressed for high forest and protected areas. From a forest species viewpoint, silver fir, coastal Mediterranean pine, beech and mixed forests seem to be more appreciated compared to other stand typologies such as oaks (e.g., pubescent or Turkey oak) and thermophilic broad-leaved species. Additional quantitative parameters (e.g., elevation, biomass stock and distance to main roads) were significant to the CES assessment. The potential applications of the technique to support forest planning and management are discussed.

Keywords: Forest Aesthetic Value, Social Network, Maximum Entropy Models, Tag-cloud, Geographic Information Systems

iForest 12 (1): 98-105 (2019) - doi: 10.3832/ifor2821-011
https://iforest.sisef.org/contents/?id=ifor2821-011

Research Articles: Seven spruce species on a mountain site - performance, foliar nutrients, and forest floor properties in stands 20 years old

Špulák O, Kacálek D, Balcar V — 2019-02-11

Špulák O, Kacálek D, Balcar V

SEVEN SPRUCE SPECIES ON A MOUNTAIN SITE - PERFORMANCE, FOLIAR NUTRIENTS, AND FOREST FLOOR PROPERTIES IN STANDS 20 YEARS OLD

Abstract: Norway spruce is often considered to have a negative impact on a site, yet it is native to many mountain regions of Europe. The relative influence of Norway spruce on site properties has frequently been compared with that of both broadleaved and other coniferous tree species. In our study, growth, as well as needle, forest floor, and topsoil chemistry were compared between Norway spruce and introduced spruce species (white, black, red, Serbian, Sitka, and blue spruce), all growing on the same, formerly polluted mountain site. There were few differences in needle nutrient status between the introduced spruce species and native Norway spruce. The chemistry of forest floor horizons beneath some of the non-native species showed less acidity and better conditions of the soil sorption complex. There were no significant differences in the nutrient pools, indicating that the influence of the various spruce species on the site was comparable. Given the small differences observed in the various nutritional characteristics, it appears that, under the conditions of the study site, the alternative spruces had substituted for the role of Norway spruce before its recovery in the 2000s. The six spruces grew quite consistently during 2001-2012, while the mean height of Norway spruce shifted from the lowest 176 cm (2001) to one of the tallest. At 710 cm (2012), its height had become comparable with that of Sitka. The poorest performing were black spruce (due to bark beetle attack) and blue spruce (due to bud blight infestation and decline).

Keywords: Spruce, Performance, Foliar Nutrients, Forest Floor, Soil

iForest 12 (1): 106-113 (2019) - doi: 10.3832/ifor2731-011
https://iforest.sisef.org/contents/?id=ifor2731-011

Short Communications: Gliding patterns of Siberian flying squirrels in relation to forest structure

Suzuki KK, Yanagawa H — 2019-02-11

Suzuki KK, Yanagawa H

GLIDING PATTERNS OF SIBERIAN FLYING SQUIRRELS IN RELATION TO FOREST STRUCTURE

Abstract: It is widely accepted that the evolution of gliding ability is correlated with forest environments, but differences in gliding locomotion in relation to forest structure remains poorly elucidated in mammals. Although the cost of gliding locomotion decreases with increasing glide distance per unit vertical drop (glide ratio), gliding mammals often use costly low-ratio glides and seldom exploit maximum-ratio glides. In this study, we evaluated our hypothesis that low-ratio glides are related to forest structure by measuring glide distance, vertical drops and landing tree heights in Siberian flying squirrels (Pteromys volans), and we also recorded their behaviour in landing trees. Glide ratio decreased with increasing landing tree height. Squirrels landed on taller trees using low-ratio glides and tended to depart from them quickly without spending much time there, but used high-ratio glides to land on shorter trees for foraging or nesting. Thus, flying squirrels use two different gliding behaviours depending on their immediate objective, where inefficient low-ratio glides are used to move to higher trees for continued gliding. This approach might be necessary for efficiency and safety in subsequent glides, because taller trees facilitate long-distance glides and significantly decrease energy costs and landing impact. Therefore, the location of tall trees in forests and/or average canopy height might alter glide path routes. This study provides important evidence that forest structure affects gliding patterns and provides insight on how forest management could influence the gliding locomotion of Siberian flying squirrels.

Keywords: Behaviour, Forest Structure, Forest Management, Gliding, Locomotion, Mammal, Tree Height

iForest 12 (1): 114-117 (2019) - doi: 10.3832/ifor2954-011
https://iforest.sisef.org/contents/?id=ifor2954-011

Research Articles: Assessment of presence and distribution of Armillaria and Heterobasidion root rot fungi in the forest of Vallombrosa (Apennines Mountains, Italy) after severe windstorm damage

Dálya LB, Capretti P, Ghelardini L, Jankovský L — 2019-02-11

Dálya LB, Capretti P, Ghelardini L, Jankovský L

ASSESSMENT OF PRESENCE AND DISTRIBUTION OF ARMILLARIA AND HETEROBASIDION ROOT ROT FUNGI IN THE FOREST OF VALLOMBROSA (APENNINES MOUNTAINS, ITALY) AFTER SEVERE WINDSTORM DAMAGE

Abstract: One of the main problems for the management and conservation of silver fir stands has long been pathogens causing root rot, in particular Armillaria spp. and Heterobasidion annosum s.l. These opportunistic pathogens are especially threatening now that climate change related stress is increasing tree susceptibility to disease and vulnerability to windstorms. The northern Apennines Mountains (central Italy) are forecast to be one of the areas with the highest temperature increase in the next future. However, no systematic assessment exists of the risk posed by the disturbance due to secondary pathogens in the Apennine forests. In the Nature Reserve of Vallombrosa (northern Apennines), where silver fir forests have been managed and conserved for centuries since the Middle Ages, making it an ideal site for studying these parasites, the high presence of H. annosum was reported already in 1990, while only sporadic observations are available on Armillaria species. The aim of this work was to examine the occurrence of both pathogens, since detailed knowledge about their distribution may assist forest management planning and decision-making. Systematic sampling was undertaken at the intersection of 52 grid points covering the whole forest. Different fungal species from soil and fungal samples (fruiting bodies or rhizomorphs) were identified by combining morphological descriptions with molecular methods. The analyses confirmed the presence of H. abietinum in about 70% of the investigated points. The fungus was detected at two new localities above 1000 metres suggesting a possible expansion of the parasite at upward elevation, which might be associated with climate change. Armillaria was widespread: almost 90% of the samples resulted positive, and four different Armillaria species were successfully identified. The most frequent species were A. cepistipes, whose rhizomorphs were especially abundant, and A. ostoyae, which was often detected just in soil samples. At sites where A. cepistipes was found to coexist with A. gallica, these two species might specialize themselves to necrotrophic and saprotrophic lifestyle, respectively. Besides, there were unexpected findings of A. mellea, supposed to be a residual from the previous rotation of broadleaves.

Keywords: Abies alba, Armillaria spp., Butt Rot, Climate Change Disturbances, Heterobasidion annosum, Root Rot, Silver Fir, Windstorm Damage

iForest 12 (1): 118-124 (2019) - doi: 10.3832/ifor2929-012
https://iforest.sisef.org/contents/?id=ifor2929-012

Research Articles: Fuel consumption comparison of two forwarders in lowland forests of pedunculate oak

Pandur Z, Šušnjar M, Bačić M, Ðuka A, Lepoglavec K, Nevečerel H — 2019-02-11

Pandur Z, Šušnjar M, Bačić M, Ðuka A, Lepoglavec K, Nevečerel H

FUEL CONSUMPTION COMPARISON OF TWO FORWARDERS IN LOWLAND FORESTS OF PEDUNCULATE OAK

Abstract: Fuel consumption of forest machinery and vehicles depends mainly on terrain conditions, working methods, drivers’ skills, engine load under working conditions, engine speed, type and technical characteristics of the machine. In timber harvesting operations, fuel consumption is significant for both, economic (costs), and environmental issues (80-95% of exhaust emissions and soot particles are associated with fuel consumption). The objective of this study was to compare fuel consumption in two different forwarders and to analyse two different measuring devices for fuel consumption. Fuel consumption was measured on a 6-wheeled Valmet 840.2 forwarder and an 8-wheeled Valmet 860.4 during roundwood and energy wood extraction in winter period. A differential fuel flow meter and a fuel measuring probe were used for measuring fuel consumption as well as a Fleet Management System (FMS) for transmitting measured data. Fuel consumption was expressed in six different ways depending on the stage of the working cycle, time, travelled distance, load volume and load mass. Finally, both the advantages and disadvantages of the used fuel measuring devices were gained. The results indicated higher fuel consumption of the smaller Valmet 840.2 forwarder due to lower soil bearing capacity and longer extraction distances. For both forwarders, higher fuel consumption (expressed in l t-1 km-1) was observed while extracting energy wood due to its lower overall mass.

Keywords: Forwarder, Fuel Measuring, Timber Extraction, Load, Roundwood, Energy Wood

iForest 12 (1): 125-131 (2019) - doi: 10.3832/ifor2872-011
https://iforest.sisef.org/contents/?id=ifor2872-011

Research Articles: Use of δ13C as water stress indicator and potential silvicultural decision support tool in Pinus radiata stand management in South Africa

Fischer PM, du Toit B — 2019-01-24

Fischer PM, du Toit B

USE OF δ13C AS WATER STRESS INDICATOR AND POTENTIAL SILVICULTURAL DECISION SUPPORT TOOL IN PINUS RADIATA STAND MANAGEMENT IN SOUTH AFRICA

Abstract: In this study, the carbon isotope ratio in tree rings was investigated as a potential measure of water availability and drought stress in Pinus radiata stands in South Africa. An understanding of water availability and its variation in space is fundamental to the implementation of increasingly site-specific management regimes that have the potential to improve stand productivity. Fourteen plantation compartments, situated on water shedding (convex) terrain were identified where reliable weather data existed and a water balance model could be run. This output was used to derive water stress indicators: (a) relative canopy conductance (gc/gcmax) and (b) the ratio of actual to potential evapotranspiration (ETa/ETp). The water stress indicators (calculated per year of growth) were related to δ13C values in five tree rings formed in the five years before mid-rotation thinning took place. The water balance model used adequately described soil water availability throughout each growing season and indicated that most severe stand water stress occurred during the summer months of the study period (November to April). The ETa/ETp ratio for this period as well as the relative canopy conductance proved to be good measures of water stress. The 5-year averages of the ETa/ETp ratios (taken over the driest 6 month period) ranged from 0.17 to 0.32 (winter rainfall zone) and 0.44 to 0.70 (all-year rainfall zone). The 5-year averages of ETa/ETp ratios could be accurately predicted (p< 0.0001; adjusted r2 = 0.83) with multiple regression using δ13C values in whole-wood samples (i.e., earlywood and latewood) and the site index of stands (where site index is the average height of the dominant 20% trees in the stand at base age 20). The δ13C values in tree rings across the planted range of P. radiata in South Africa can therefore be used to identify broad categories of water availability for purposes of increasingly site-specific silvicultural management.

Keywords: Stable Carbon Isotope, Tree Rings, Water Availability, Drought Stress, Site-specific Forest Management, Monterey Pine

iForest 12 (1): 51-60 (2019) - doi: 10.3832/ifor2628-011
https://iforest.sisef.org/contents/?id=ifor2628-011

Research Articles: Gas exchange, biomass allocation and water-use efficiency in response to elevated CO2 and drought in andiroba (Carapa surinamensis, Meliaceae)

Oliveira MF, Marenco RA — 2019-01-24

Oliveira MF, Marenco RA

GAS EXCHANGE, BIOMASS ALLOCATION AND WATER-USE EFFICIENCY IN RESPONSE TO ELEVATED CO2 AND DROUGHT IN ANDIROBA (CARAPA SURINAMENSIS, MELIACEAE)

Abstract: Prolonged droughts are predicted for some parts of the Amazon; however, it is still unclear how Amazonian trees will respond to water stress under the ongoing increase in CO2 concentration. The aim of this study was to assess the effect of elevated CO2 (eCO2) and drought on photosynthetic rates, water-use efficiency, and biomass allocation in andiroba (Carapa surinamensis). The plants were grown in pots at ambient (400 ppm CO2) and eCO2 (700 ppm) at two water regimes, soil at 50% field capacity, FC (drought) and soil at 100% FC for 163 days. We measured light saturated photosynthesis on a mass basis (Asat-mass), stomatal conductance to CO2 on a mass basis (gsCO2-mass), whole-plant water-use efficiency (WUEP), biomass accumulation, specific leaf area (SLA) and total leaf area. At eCO2, Asat-mass increased 28% in well-watered plants and 93% under drought, whereas gsCO2-mass declined 39% in well-watered plants at eCO2, with no effect of drought on gsCO2-mass at eCO2. The total biomass gain improved 73% at eCO2 and over CO2 levels it was reduced (54%) by drought. WUEP improved (188%) at eCO2 in well-watered plants and 262% under drought. SLA declined 23% at eCO2, but the effect of drought on SLA was null. On the contrary, total leaf area was greatly reduced (67%) by drought, but it was not affected by eCO2. The large increase in total biomass and the substantial improvement in WUEP under eCO2, and the sharp decline in leaf area under water stress widen our knowledge on the physiology of this important species for the forest management of large areas in the Amazon region.

Keywords: Carboxylation Efficiency, Nonstructural Carbohydrates, Specific Leaf Area, Shoot-root Ratio, Tree Growth

iForest 12 (1): 61-68 (2019) - doi: 10.3832/ifor2813-011
https://iforest.sisef.org/contents/?id=ifor2813-011

Research Articles: Allometric models for estimating biomass, carbon and nutrient stock in the Sal zone of Bangladesh

2019-01-24

Mahmood H, Siddique MR, Costello L, Birigazzi L, Abdullah SR, Henry M, Siddiqui BN, Aziz T, Ali S, Al Mamun A, Forhad MI, Akhter M, Iqbal Z, Mondol FK

ALLOMETRIC MODELS FOR ESTIMATING BIOMASS, CARBON AND NUTRIENT STOCK IN THE SAL ZONE OF BANGLADESH

Abstract: Allometric models are commonly used to estimate biomass, nutrients and carbon stocks in trees, and contribute to an understanding of forest status and resource dynamics. The selection of appropriate and robust models, therefore, have considerable influence on the accuracy of estimates obtained. Allometric models can be developed for individual species or to represent a community or bioregion. In Bangladesh, the nation forest inventory classifies tree and forest resources into five zones (Sal, Hill, Coastal, Sundarbans and Village), based on their floristic composition and soil type. This study has developed allometric biomass models for multi-species of the Sal zone. The forest of Sal zone is dominated by Shorea robusta Roth. The study also investigates the concentrations of Nitrogen, Phosphorus, Potassium and Carbon in different tree components. A total of 161 individual trees from 20 different species were harvested across a range of tree size classes. Diameter at breast height (DBH), total height (H) and wood density (WD) were considered as predictor variables, while total above-ground biomass (TAGB), stem, bark, branch and leaf biomass were the output variables of the allometric models. The best fit allometric biomass model for TAGB, stem, bark, branch and leaf were: ln (TAGB) = -2.460 + 2.171 ln (DBH) + 0.367 ln (H) + 0.161 ln (WD); ln (Stem) = -3.373 + 1.934 ln (DBH) + 0.833 ln (H) + 0.452 ln (WD); ln (Bark) = -5.87 + 2.103 ln (DBH) + 0.926 ln (H) + 0.587 ln (WD); ln (Branch) = -3.154 + 2.798 ln (DBH) - 0.729 ln (H) - 0.355 ln (WD); and ln (Leaf) = -4.713 + 2.066 ln (DBH), respectively. Nutrients and carbon concentration in tree components varied according to tree species and component. A comparison to frequently used regional and pan-tropical biomass models showed a wide range of model prediction error (35.48 to 85.51%) when the observed TAGB of sampled trees were compared with the estimated TAGB of the models developed in this study. The improved accuracy of the best fit model obtained in this study can therefore be used for more accurate estimation of TAGB and carbon and nutrients in TAGB for the Sal zone of Bangladesh.

Keywords: Common Model, Forest Inventory, Phytomass, Tropical Forest

iForest 12 (1): 69-75 (2019) - doi: 10.3832/ifor2758-011
https://iforest.sisef.org/contents/?id=ifor2758-011

Research Articles: Biodiversity conservation and wood production in a Natura 2000 Mediterranean forest. A trade-off evaluation focused on the occurrence of microhabitats

Santopuoli G, di Cristofaro M, Kraus D, Schuck A, Lasserre B, Marchetti M — 2019-01-24

Santopuoli G, di Cristofaro M, Kraus D, Schuck A, Lasserre B, Marchetti M

BIODIVERSITY CONSERVATION AND WOOD PRODUCTION IN A NATURA 2000 MEDITERRANEAN FOREST. A TRADE-OFF EVALUATION FOCUSED ON THE OCCURRENCE OF MICROHABITATS

Abstract: The most significant European forest-related strategies highlight the importance of multifunctional forests for human wellbeing, due to the provision of a wide range of goods and services. However, managing competing aims, such as timber production, economic drivers and biodiversity conservation is often difficult for practitioners. In order to assess the loss and gain of ecosystem services caused by forestry, trade-off evaluation has been increasingly used to aid decision-making. In this study, four silvicultural scenarios are simulated using the Marteloscope approach to evaluate the trade-offs between biodiversity conservation and timber production. Tree-related Microhabitats (TreMs) are used as a proxy to evaluate forest habitat value, while timber production is assessed by the number of harvested trees, biomass removal and economic income. This study takes an innovative approach by investigating TreMs using the Marteloscope in mixed Mediterranean forest. The main findings from this paper confirm that tree-related microhabitats can be considered ecological indicators effective in identifying important habitat trees, to assess forest habitat value and support tree marking for thinning operations and management.

Keywords: Biodiversity Conservation, Sustainable Forest Management, Microhabitats, Habitat Tree, Marteloscope, Timber Production, Precision Forestry

iForest 12 (1): 76-84 (2019) - doi: 10.3832/ifor2617-011
https://iforest.sisef.org/contents/?id=ifor2617-011

Research Articles: Assessing food sustainable intensification potential of agroforestry using a carbon balance method

Crous-Duran J, Graves AR, Garcia-de-Jalón S, Paulo JA, Tomé M, Palma JH — 2019-01-24

Crous-Duran J, Graves AR, Garcia-de-Jalón S, Paulo JA, Tomé M, Palma JH

ASSESSING FOOD SUSTAINABLE INTENSIFICATION POTENTIAL OF AGROFORESTRY USING A CARBON BALANCE METHOD

Abstract: Food security, climate change mitigation, and land use challenges are interlinked and need to be considered simultaneously. One possible solution is sustainable intensification, which is the practice of increasing food production per area of land whilst also reducing the environmental impacts associated with this. Agroforestry has been stated to be a practice that meets this definition. In this study, a new methodology is presented to assess the potential of different management options as sustainable intensification practices. The methodology is based on comparing the carbon emissions associated with the production of food and the carbon sequestered for that same activity for a particular quantity of food produced over a specific area and over a specific time. The resulting indicator, the “carbon balance” is the difference between the greenhouse gasses emitted (considered as negative values) and carbon sequestered (positive values) estimated in Mg CO2eq per Mg of food produced on one hectare of land for one year. The carbon balance quantifies the global warming potential associated with sustainable intensification by integrating a process-based model with life cycle analysis and is able to estimate above- and below-ground biomass and soil carbon content. This methodology is tested in Portugal for wheat production under crop monoculture and agroforestry systems. The results show agroforestry to be a suitable practice for sustainable intensification compared to a crop monoculture as it just slightly decreased wheat yields whilst providing a positive carbon balance from year 50 onwards of approximately 1 Mg of CO2eq sequestered per Mg of wheat produced.

Keywords: Climate Change Mitigation, Food Security, Land-use Occupation, Regulating Ecosystem Services, Soil Fertility, Life Cycle Analysis, Yield-SAFE, Clipick, Carbon Sequestration

iForest 12 (1): 85-91 (2019) - doi: 10.3832/ifor2578-011
https://iforest.sisef.org/contents/?id=ifor2578-011

Research Articles: Changes in moisture exclusion efficiency and crystallinity of thermally modified wood with aging

Tarmian A, Mastouri A — 2019-01-24

Tarmian A, Mastouri A

CHANGES IN MOISTURE EXCLUSION EFFICIENCY AND CRYSTALLINITY OF THERMALLY MODIFIED WOOD WITH AGING

Abstract: This study aimed to investigate whether aging affects moisture exclusion efficiency and crystallinity of thermally modified wood. For this purpose, wood blocks of hornbeam (Carpinus betulus), Norway spruce (Picea abies) and oak (Quercus castanifolia), modified at 180 °C for 3 hours inside a ThermoWood kiln were exposed to a six-cycle artificial aging procedure. Aging reduced the efficiency and crystallinity of the modified woods. A significant negative correlation was found between the wood crystallinity and equilibrium moisture content (EMC) which indicates that change in the crystallinity index (CrI) measured by X-ray diffraction (XRD) affects the affinity of wood to moisture. The increased affinity of the modified wood to moisture after aging is probably due to the leaching of thermal degradation products as observed by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy.

Keywords: Aging, Crystallinity, Moisture Exclusion Efficiency, Thermally Modified Wood

iForest 12 (1): 92-97 (2019) - doi: 10.3832/ifor2723-011
https://iforest.sisef.org/contents/?id=ifor2723-011

Review Papers: Quantifying and modeling water availability in temperate forests: a review of drought and aridity indices

Speich MJR — 2019-01-10

Speich MJR

QUANTIFYING AND MODELING WATER AVAILABILITY IN TEMPERATE FORESTS: A REVIEW OF DROUGHT AND ARIDITY INDICES

Abstract: Climatic water availability is a major determinant of forest structure and composition, while drought events may severely impact forest dynamics. In recent decades, an increasing number of severe drought events has been reported in forests around the world. In the future, climate models project increasingly dry conditions in many temperate regions. Various tools have been applied to better understand the effects of drought on forests, such as dendrochronological analyses, climatic trend analyses and dynamic models. With these approaches, water availability is often summarized as a single scalar, termed a drought or aridity index. As droughts are complex phenomena, such indices are always associated with a loss of information. Many different such indices exist, and have been developed for various purposes. This review asks whether some of these indices are more suitable than others to quantify water availability in temperate forests. In a first step, the rationale and theoretical background of different drought indices are spelled out and compared among each other. Then, evaluations and intercomparisons of drought indices from the literature are reviewed. The implementation of drought indices in dynamic forest models is also discussed. Finally, two current research questions are identified: the role of dry air for physiological drought, and the suitability of various drought indices under climate change. It appears from this review that indices accounting for evaporative demand generally perform better than indices based on precipitation alone. When comparing sites with different edaphic conditions, indices accounting for soil moisture storage are more suitable. Nevertheless, results from intercomparisons show considerable divergence, and it is not possible to clearly favor one index. Furthermore, a differential response of tree species to different drought indices is often observed, although no clear pattern emerges from this comparison. More intercomparisons of indices, across climates and species, might provide valuable knowledge. Another key finding is that the properties of indices also depend on choices regarding, e.g., the calculation of evaporative demand, or the underlying water balance model. Reporting such methodological details could greatly increase the value of future evaluations of drought indices.

Keywords: Drought Indices, Water Availability, Soil Moisture, Climate Change, Dynamic Forest Modeling

iForest 12 (1): 1-16 (2019) - doi: 10.3832/ifor2934-011
https://iforest.sisef.org/contents/?id=ifor2934-011

Research Articles: Patterns of forest dynamics in a secondary old-growth beech-dominated forest in the Jizera Mountains Beech Forest Reserve, Czech Republic

2019-01-10

Lábusová J, Morrissey RC, Trotsiuk V, Janda P, Bače R, Cada V, Mikoláš M, Mrhalová H, Schurman JS, Svobodová K, Mateju L, Synek M, Svoboda M

PATTERNS OF FOREST DYNAMICS IN A SECONDARY OLD-GROWTH BEECH-DOMINATED FOREST IN THE JIZERA MOUNTAINS BEECH FOREST RESERVE, CZECH REPUBLIC

Abstract: Restoring the structural characteristics of secondary old-growth forests that were previously managed is increasingly debated to help increase the area of more complex forests which provide a broader array of forest services and functions. The paucity of long-term data sets in Central Europe has limited our ability to understand the ongoing ecological processes required for effective restoration programs for old-growth forests. To address this, we used repeated census data from eight permanent plots to evaluate forest structural dynamics over a 12-year period in the largest complex of European beech (Fagus sylvatica L.) forests in the Czech Highlands without intensive forestry intervention for almost 50 years. Our results showed that previously managed forests can exhibit structural qualities typically associated with old-growth forests after management has ceased for a period. The stand structural characteristics (e.g., density of large and old trees) is comparable with protected reserves of old-growth European beech-dominated forests. The average stand age was 196 years, but the oldest tree was 289 years old. The annual mortality rate was 0.43% for all species, and the U-shaped distribution indicating size-dependent mortality is likely an important process that is balanced by the turnover of new tree recruitment. During the study period, we detected that the diameter distribution tended towards a rotated sigmoid distribution. The lasting effects of the most recent forest management are evident in the scarcity of dead wood, and a prolonged process of dead wood accumulation has begun. Thus, the abandonment of all management activities in near-natural forest reserves, including dead wood removal, will ensure that the forests will develop characteristics typical of old-growth forests.

Keywords: Dead Wood, Diameter Distribution, Fagus sylvatica, Forest Reserve, Forest Structure, Mortality, Old-growth Forest

iForest 12 (1): 17-26 (2019) - doi: 10.3832/ifor2702-011
https://iforest.sisef.org/contents/?id=ifor2702-011

Research Articles: Effects of mild drought on the morphology of sun and shade needles in 20-year-old Norway spruce trees

Gebauer R, Volarík D, Urban J, Børja I, Nagy NE, Eldhuset TD, Krokene P — 2019-01-10

Gebauer R, Volarík D, Urban J, Børja I, Nagy NE, Eldhuset TD, Krokene P

EFFECTS OF MILD DROUGHT ON THE MORPHOLOGY OF SUN AND SHADE NEEDLES IN 20-YEAR-OLD NORWAY SPRUCE TREES

Abstract: Several studies have looked at how individual environmental factors influence needle morphology in conifer trees, but interacting effects between drought and canopy position have received little attention. In this study, we characterized morphological responses to experimentally induced drought stress in sun exposed and shaded current-year Norway spruce needles. In the drought plot trees were suffering mild drought stress, with an average soil water potential at 50 cm depth of -0.4 MPa. In general, morphological needle traits had greater values in sun needles in the upper canopy than in shaded needles in the lower canopy. Needle morphology 15 months after the onset of drought was determined by canopy position, as only sun needle morphology was affected by drought. Thus, canopy position was a stronger morphogenic factor determining needle structure than was water availability. The largest influence of mild drought was observed for needle length, projected needle area and total needle area, which all were reduced by ~27% relative to control trees. Needle thickness and needle width showed contrasting sensitivity to drought, as drought only affected needle thickness (10% reduction). Needle dry mass, leaf mass per area and needle density were not affected 15 months after the onset of mild drought. Our results highlight the importance of considering canopy position as well as water availability when comparing needle structure or function between conifer species. More knowledge about how different canopy parts of Norway spruce adapt to drought is important to understand forest productivity under changing environmental conditions.

Keywords: Canopy Position, Drought, Crown Light Gradient, Needle Structure, Picea abies, Transpiration

iForest 12 (1): 27-34 (2019) - doi: 10.3832/ifor2809-011
https://iforest.sisef.org/contents/?id=ifor2809-011

Research Articles: Dimensionless numbers for the net present value and the perpetual value of sustainable timber harvests from a monospecific uneven-aged forest

López Torres I, Belda Fullana C — 2019-01-10

López Torres I, Belda Fullana C

DIMENSIONLESS NUMBERS FOR THE NET PRESENT VALUE AND THE PERPETUAL VALUE OF SUSTAINABLE TIMBER HARVESTS FROM A MONOSPECIFIC UNEVEN-AGED FOREST

Abstract: This paper proposes a simple and direct method to provide reliable approximations of the net present value (NPV) and the perpetual value (PV) of sustainable timber harvests from a monospecific uneven-aged forest based on dimensionless numbers. In addition, two new dimensionless numbers ρNPV and ρPV are introduced. These use the NPV or PV derived from the sale of timber throughout a harvest cycle, plus the final stocking value (as numerator), and the fair value of standing timber under IAS 41 (as denominator). They can be interpreted as economic performance indicators for forest management, inspired by the return on assets accounting concept, showing how profitable the forest is, relative to its total value, with sustainability and stability criteria. Those approximations to the variables NPV, PV, ρNPV and ρPV, were obtained under conditions of stable equilibrium from a matrix model. In order to exemplify and test the results, the model used data from uneven-aged managed Pinus nigra stands, considering three levels of tree diameter growth, six levels of basal area and 33 levels of recruitment, creating a total of 594 planning scenarios. Furthermore, the study revealed the existence of strong linear correlations between those variables and a dimensionless number.

Keywords: Dimensionless Numbers, NPV/PV, Equilibrium, Sustainable Harvesting, Matrix Model, IAS 41

iForest 12 (1): 35-42 (2019) - doi: 10.3832/ifor2715-011
https://iforest.sisef.org/contents/?id=ifor2715-011

Research Articles: Ectomycorrhizae of Norway spruce from its southernmost natural distribution range in Serbia

Katanić M, Orlović S, Grebenc T, Bajc M, Pekeč S, Drekić M, Kraigher H — 2019-01-10

Katanić M, Orlović S, Grebenc T, Bajc M, Pekeč S, Drekić M, Kraigher H

ECTOMYCORRHIZAE OF NORWAY SPRUCE FROM ITS SOUTHERNMOST NATURAL DISTRIBUTION RANGE IN SERBIA

Abstract: Norway spruce (Picea abies Karst.) reaches its southernmost limit in the mountainous regions of south Serbia and Bulgaria. The species is a regionally important timber species for the wood industry and a significant host for various ectomycorrhizal fungi, including edible species. We analysed ectomycorrhizal community and fine root parameters of high continental / subalpine Norway spruce stands at three sites (Stara planina, Kopaonik, Tara) located in protected areas in Serbia. In addition, we assessed the potential effects of altitude and growing season on the ectomycorrhizal diversity and fine root parameters. Using standardised sampling in combination with morpho-anatomical and molecular identification of ectomycorrhizae, we recorded 29 different anatomorphotypes. None of the identified fungi belonged to commercial edible fungal species. Compared to other Norway spruce ectomycorrhiza studies in central Europe, sites in Serbia exhibited lower species diversity and different dominant species composition, with Cenococcum spp. and Russula spp. as the dominant ectomycorrhizal fungi. A number of ectomycorrhizal types and the value of the species richness index differed between Stara planina and Tara in the autumn, but the influence of site and season on the studied diversity indices was not significant. The total number of fine roots increased in the spring, while percentage of vital ectomycorrhizal root tips increased in the autumn. This study was the first examination of Norway spruce ectomycorrhizal communities at the edge of the natural geographical range of the species.

Keywords: Ectomycorrhiza, Picea abies Karst., Community Structure, Diversity, Fine Roots

iForest 12 (1): 43-50 (2019) - doi: 10.3832/ifor2729-011
https://iforest.sisef.org/contents/?id=ifor2729-011

Research Articles: Assessing the relative role of climate on litterfall in Mediterranean cork oak forests

Andivia E, Bou J, Fernández M, Caritat A, Alejano R, Vilar L, Vázquez-Piqué J — 2018-12-14

Andivia E, Bou J, Fernández M, Caritat A, Alejano R, Vilar L, Vázquez-Piqué J

ASSESSING THE RELATIVE ROLE OF CLIMATE ON LITTERFALL IN MEDITERRANEAN CORK OAK FORESTS

Abstract: Litterfall plays a key role in the dynamic of forest ecosystems, ultimately determining forest productivity and carbon and nutrient cycling. Increasing our understanding on the role of structural and environmental factors controlling litterfall amount and seasonality is of paramount importance for modelling and estimating soil carbon sequestration and nutrient cycling under climate change scenarios. However, the effect of climatic conditions on litterfall has been scarcely studied, especially in Mediterranean ecosystems. Here, we used nine years of seasonally collected litterfall data in two contrasting Mediterranean cork oak forests to evaluate the effect of climatic variables on leaf fall and litterfall. First, we isolated the litterfall seasonal trend and the between-sites differences in production by using linear mixed models. Then, we evaluated the effect of climatic variables and whether this effect was site-specific. We found a consistent litterfall seasonal pattern, mainly determined by leaf shedding (70% of litterfall). Leaf fall mainly occurs in spring with a second but much smaller peak in autumn some years. Mean temperature, precipitation and mean wind speed strongly influenced litterfall, but this effect was site-specific. In the forest site located at higher latitude and altitude, leaf fall increased linearly with temperature and showed a positive quadratic response to precipitation. In the water-limited site, leaf fall was reduced as temperature increased and did not respond to precipitation. These results have implications for modelling and predicting soil carbon sequestration, nutrient cycling, and the forest ecosystem productivity. Specifically, carbon and nutrient cycling models can be improved by incorporating idiosyncratic forest sites responses to climatic variability.

Keywords: Climate, Leaf Fall, Litterfall, Modelling, Plant-soil Interactions, Quercus suber, Seasonality

iForest 11 (6): 786-793 (2018) - doi: 10.3832/ifor2825-011
https://iforest.sisef.org/contents/?id=ifor2825-011

Research Articles: Effect of exogenous nitrogen and phosphorus inputs on the microbe-soil interaction in the secondary Castanopsis sclerophylla forest in east China

Teng Z, Cui J, Wang J, Fu X, Xu X — 2018-12-14

Teng Z, Cui J, Wang J, Fu X, Xu X

EFFECT OF EXOGENOUS NITROGEN AND PHOSPHORUS INPUTS ON THE MICROBE-SOIL INTERACTION IN THE SECONDARY CASTANOPSIS SCLEROPHYLLA FOREST IN EAST CHINA

Abstract: Soil microbes play a key role in the formation and decomposition of organic materials and in the improvement of the ecological environment. Despite continuous increases in nitrogen (N) and phosphorus (P) inputs due to the atmospheric deposition or fertilization, the response of soil to exogenous inorganic nutrients inputs remains elusive. By a manipulative experiment we simulated N and P depositions in a subtropical secondary Castanopsis sclerophylla forest in east China over the period 2011-2015, to evaluate the impact of inorganic nutrient addition on soil bacterial communities. Four treatments were administered (control and nutrient-enrichment: N, P, and N+P), with N added at a total of 100 kg N ha-1 yr-1 in the form of NH4NO3, and P at 50 kg P ha-1 yr-1 in Ca(H2PO4)2, sprayed near the soil surface at the end of each trimester. Quantitative PCR technique and Illumina platform-based sequencing analysis of the V3-V4 16S rRNA gene region were performed on total DNA extracted from soil samples to characterize the soil bacterial community abundance and diversity. As Proteobacteria, Acidobacteria and Actinobacteria were the predominant phyla in all conditions, treatments did not alter the distribution of bacterial phyla, while their relative abundances responded differently to N, P additions. A GLMM analysis showed that N input significantly (P < 0.05) reduced the relative abundance of Acidobacteria (13.11%), Bacteroidetes (0.6%), Elusimicrobia (0.21%), Nitrospirae (0.1%) and TM6 (0.04%). Relative abundance after P treatment significantly (P < 0.01) decreased for Nitrospirae (0.07%), and pronounced interactive effects of N and P additions (N:P) were observed on phylum Nitrospirae (P < 0.01) and TM6 (P < 0.05). Moreover, redundancy analysis revealed that soil pH was closely related to the bacterial community (r2 = 0.622, P = 0.015). Our findings suggest that exogenous N and P inputs affected the relative abundances and caused compositional shifts in the local bacterial community that closely associated with soil pH, thus providing the evidence that microbe-soil interactions are influenced by N and P availability in subtropical forest ecosystem of east China.

Keywords: 16S rRNA, Nitrogen and Phosphorus Additions, Bacterial Populations, Soil PH, Subtropical Secondary Castanopsis sclerophylla Forest

iForest 11 (6): 794-801 (2018) - doi: 10.3832/ifor2673-011
https://iforest.sisef.org/contents/?id=ifor2673-011

Research Articles: Diversity and distribution patterns of medium to large mammals in a silvicultural landscape in south-eastern Brazil

Campos BM, Charters JD, Verdade LM — 2018-12-14

Campos BM, Charters JD, Verdade LM

DIVERSITY AND DISTRIBUTION PATTERNS OF MEDIUM TO LARGE MAMMALS IN A SILVICULTURAL LANDSCAPE IN SOUTH-EASTERN BRAZIL

Abstract: Agricultural landscapes cover approximately 35% of Brazil and are the second greatest threat to biodiversity worldwide. In Brazil, seven millions hectars of land is covered with Eucalyptus plantations, which is considered to have low conservation value. However, studies have shown that heterogeneous silvicultural landscapes, made up of Eucalyptus matrices and patches dedicated to conservation, are able to support a considerable diversity of wild mammals. This study aims to assess the diversity and distribution patterns of medium-to-large-sized mammals in a silvicultural landscape in Angatuba, São Paulo, Brazil. Nineteen species were detected by camera traps within the study area. Diversity indices did not vary among habitat types (i.e., native vegetation, abandoned pasture and Eucalyptus plantations), suggesting that the species use the landscape as a whole. A relatively diverse range of predator species was found in the area, suggesting that future monitoring programs should focus on predator-prey relationships. A low diversity of frugivores was detected, indicating that management actions should be taken to facilitate their local recovery. Our results stress the fundamental importance of the conservation areas (Permanent Preservation Areas and Legal Reserve) in silvicultural landscapes, as these areas help maintain complexity of the landscape structure.

Keywords: Agroecosystem, Wildlife Management, Mammals, Eucalyptus, Camera-trapping

iForest 11 (6): 802-808 (2018) - doi: 10.3832/ifor2721-011
https://iforest.sisef.org/contents/?id=ifor2721-011

Research Articles: Environmental factors affecting formation of lammas shoots in young stands of Norway spruce (Picea abies Karst.) in Latvia

Katrevics J, Neimane U, Dzerina B, Kitenberga M, Jansons J, Jansons A — 2018-12-14

Katrevics J, Neimane U, Dzerina B, Kitenberga M, Jansons J, Jansons A

ENVIRONMENTAL FACTORS AFFECTING FORMATION OF LAMMAS SHOOTS IN YOUNG STANDS OF NORWAY SPRUCE (PICEA ABIES KARST.) IN LATVIA

Abstract: Norway spruce is a relatively fast-growing tree species that is primarily regenerated by planting, which requires significant investments. The formation of lammas shoots (i.e., second flushing in late summer) have been proven to affect the quality and productivity of Norway spruce stands. The aim of our study was to assess the proportion of trees with lammas shoots in young stands of Norway spruce and to investigate the factors affecting their formation. Data have been collected at the end of 2011 in 102 three- to seven-year-old Norway spruce plantations randomly selected across different forest types in the central part of Latvia, and a subset of 21 stands were inventoried again at the end of 2012. In each stand, 20 sample plots were systematically established where trees with and without lammas shoots were counted and micro-environmental factors (moisture, competition, and browsing) were assessed on a three-grade scale. On average, the proportion of trees with lammas shoots was 6.5%. There was no significant effect of the stand age (from 3 to 7 years) on the proportion of trees with lammas shoots nor was there any age-related trend. The effect of forest type on the presence of lammas shoots was not significant. Micro-environmental factors had an important influence on the proportion of trees with lammas shoots. The proportion of lammas shoots in stands with no competition was significantly higher (14.5%) compared to stands with medium and high competition (6.0% and 2.2%, respectively). Similarly, a significantly higher proportion of trees with lammas shoots (11.7%) was observed in sites with normal moisture regime than in sites with slight or notable excess moisture, reaching 4.8% and 1.7%, respectively. Although the influence of browsing damage was not statistically significant, its trend was similar to that observed for competition and moisture regime. Overall, the proportion of trees with lammas shoots was highest in stands showing the most suitable micro-environmental conditions for Norway spruce.

Keywords: Second Flushing, Vegetation Competition, Tending, Moisture Excess, Browsing Damage

iForest 11 (6): 809-815 (2018) - doi: 10.3832/ifor2539-011
https://iforest.sisef.org/contents/?id=ifor2539-011

Research Articles: Distribution and habitat suitability of two rare saproxylic beetles in Croatia - a piece of puzzle missing for South-Eastern Europe

Rukavina I, Kostanjšek F, Jelaska SD, Pirnat A, Šerić Jelaska L — 2018-11-28

Rukavina I, Kostanjšek F, Jelaska SD, Pirnat A, Šerić Jelaska L

DISTRIBUTION AND HABITAT SUITABILITY OF TWO RARE SAPROXYLIC BEETLES IN CROATIA - A PIECE OF PUZZLE MISSING FOR SOUTH-EASTERN EUROPE

Abstract: Due to habitat loss and fragmentation, the hermit beetle, Osmoderma eremita species complex (Coleoptera; Scarabidae) and the European red click beetle, Elater ferrugineus Linnaeus, 1758 (Coleoptera: Elateridae) are considered threatened in many European countries. Their presence in a large part of South-Eastern Europe has been sporadically recorded and these findings are mainly historical. Here we present the most recent findings of both species, assembled mainly throughout this first systematic study aiming to collect data on the hermit beetle within mapping and monitoring activities of saproxylic species protected by the European Habitat Directive (Annexes II and IV of Council Directive 92/43/EEC) within the Mediterranean, Continental and Alpine biogeographical regions of Croatia, and current literature data. To facilitate mapping activities and species range monitoring to improve the proper management of suitable habitats, we created habitat suitability maps using recent findings for both species, and predicted distribution were overlapped and analysed with historical data and protected areas. Most of the individuals were captured using flight intercept cross-vein funnel traps baited with pheromone for the hermit beetle placed within natural forest dominated by oak, beech and montane beech-fir forests, on sites with and without any forest management. Among set of 11 environmental variables, autumn precipitation, spring mean temperature and slope contributed most to the beetle distribution models. Data analyses indicated that the European red click beetle has much wider environmental envelope in which it can occur and that the hermit beetle can be used as surrogate species for the European red click beetle.

Keywords: European Red Click Beetle, Hermit Beetle, Mapping and Monitoring, MaxEnt, Natura 2000, Nature Conservation, Protected Areas

iForest 11 (6): 765-774 (2018) - doi: 10.3832/ifor2753-011
https://iforest.sisef.org/contents/?id=ifor2753-011

Research Articles: Is Tuber brumale a threat to T. melanosporum and T. aestivum plantations?

Ori F, Leonardi P, Stagnini E, Balestrini V, Iotti M, Zambonelli A — 2018-11-28

Ori F, Leonardi P, Stagnini E, Balestrini V, Iotti M, Zambonelli A

IS TUBER BRUMALE A THREAT TO T. MELANOSPORUM AND T. AESTIVUM PLANTATIONS?

Abstract: True truffles in the genus Tuber are the most valuable ectomycorrhizal fungi and their cultivation has become widespread around the world. Competition with other ectomycorrhizal fungi and especially with undesired Tuber species, like T. brumale, can threaten the success of a truffle plantation. In this work, the competitiveness of T. brumale towards T. melanosporum and T. aestivum was assessed in a 14 year-old plantation carried out planting seedlings inoculated with these three truffle species in adjacent plots. Analyses of both truffle ectomycorrhizas and extra-radical mycelium were carried out in the transects separating the T. brumale plot from T. melanosporum and T. aestivum plots. The results confirm the competitiveness of T. brumale against T. aestivum and T. melanosporum due to its major ability to colonize the soil around its ectomycorrhizas. However, its competitiveness is limited to the transect areas and it was never found inside T. melanosporum plot. These results remark that, in presence of optimal conditions for T. melanosporum and T. aestivum, the greatest risk of contamination with T. brumale is due to wrong greenhouse activity.

Keywords: Competition, Black Truffles, Extra-Radical Mycelium, Ectomycorrhizas, Species-Specific Primers

iForest 11 (6): 775-780 (2018) - doi: 10.3832/ifor2785-011
https://iforest.sisef.org/contents/?id=ifor2785-011

Short Communications: Culturable fungi associated with wood decay of Picea abies in subalpine forest soils: a field-mesocosm case study

2018-11-28

Oliveira Longa CM, Francioli D, Gómez-Brandón M, Ascher-Jenull J, Bardelli T, Pietramellara G, Egli M, Sartori G, Insam H

CULTURABLE FUNGI ASSOCIATED WITH WOOD DECAY OF PICEA ABIES IN SUBALPINE FOREST SOILS: A FIELD-MESOCOSM CASE STUDY

Abstract: Fungi are the principal wood decomposers in forest ecosystems and their activity provides wood necromass to other living organisms. However, the wood decay mechanisms and the associated microbial community are largely unknown, especially in Alpine areas. In this study, the culturable fraction of fungal communities associated with the decomposition of Norway spruce (Picea abies [L.] Karst) deadwood in subalpine forest soils were determined using microbiological methods coupled with molecular identification. Fungal communities were evaluated using in-field mesocosms after one year of exposition of P. abies wood blocks along an altitudinal gradient ranging from 1200 up to 2000 m a.s.l. comprising eight subalpine sites, four of them located at north- and other four at south-facing slopes. Although many saprotrophic species were isolated from the wood blocks, several white-rot species as the pathogenic fungi Armillaria cepistipes and Heterobasidion annosum, along with soft-rot fungi such as Lecytophora sp. were identified. Our results further indicated that the wood-inhabiting fungal community was mainly influenced by topographic features and by the chemical properties of the wood blocks, providing first insights into the effect of different slope exposure on the deadwood mycobiome in the subalpine forest ecosystem.

Keywords: Wood-inhabiting Fungi, Basidiomycota, Subalpine Forest, Wood Decomposition, Norway Spruce, Slope Exposure

iForest 11 (6): 781-785 (2018) - doi: 10.3832/ifor2846-011
https://iforest.sisef.org/contents/?id=ifor2846-011

Research Articles: Prediction of ozone effects on net ecosystem production of Norway spruce forest

Jurán S, Edwards-Jonášová M, Cudlín P, Zapletal M, Šigut L, Grace J, Urban O — 2018-11-15

Jurán S, Edwards-Jonášová M, Cudlín P, Zapletal M, Šigut L, Grace J, Urban O

PREDICTION OF OZONE EFFECTS ON NET ECOSYSTEM PRODUCTION OF NORWAY SPRUCE FOREST

Abstract: Future ground-level concentrations of phytotoxic ozone are projected to grow in the Northern Hemisphere, at a rate depending on emission scenarios. We explored the likely changes in net ecosystem production (NEP) due to the increasing concentration of tropospheric ozone by applying a Generalized Additive Mixed Model based on measurements of ozone concentration ([O3]) and stomatal ozone flux (FsO3), at a mountainous Norway spruce forest in the Czech Republic, Central Europe. A dataset covering the growing period (May-August 2009) was examined in this case study. A predictive model based on FsO3 was found to be marginally more accurate than a model using [O3] alone for prediction of the course of NEP when compared to NEP measured by the eddy covariance technique. Both higher [O3] and FsO3 were found to reduce NEP. NEP simulated at low, pre-industrial FsO3 (0.5 nmol m-2 s-1) was higher by 24.8% as compared to NEP assessed at current rates of FsO3 (8.32 nmol m-2 s-1). However, NEP simulated at high FsO3 (17 nmol m-2 s-1), likely in the future, was reduced by 14.1% as compared to NEP values at current FsO3. The interaction between environmental factors and stomatal conductance is discussed in this paper.

Keywords: Carbon, CO2 Assimilation, Model, Stomatal Ozone Flux

iForest 11 (6): 743-750 (2018) - doi: 10.3832/ifor2805-011
https://iforest.sisef.org/contents/?id=ifor2805-011

Research Articles: The responses of soil microbial community and enzyme activities of Phoebe zhennan cultivated under different soil moisture conditions to phosphorus addition

Olatunji OA, Pan K, Tariq A, Zhang L, Wu X, Sun X, Luo H, Song D, Li N — 2018-11-15

Olatunji OA, Pan K, Tariq A, Zhang L, Wu X, Sun X, Luo H, Song D, Li N

THE RESPONSES OF SOIL MICROBIAL COMMUNITY AND ENZYME ACTIVITIES OF PHOEBE ZHENNAN CULTIVATED UNDER DIFFERENT SOIL MOISTURE CONDITIONS TO PHOSPHORUS ADDITION

Abstract: The importance of conservation and ecological restoration of the rare and economically important tree Phoebe zhennan is increasingly recognized. To this purpose, phosphorus (P) addition has been proposed to improve soil biological attributes and face the anticipated drought under climate change, though few studies have investigated its effect on the interaction between the soil microorganisms and plant host, as well as on ecosystem productivity. We investigated the effect of P addition on soil chemical properties, microbial communities, and enzyme activities in a soil planted with P. zhennan under two levels of water treatments (optimum water and drought treatments). P additions had no significant effect on microbial communities, dissolved organic nitrogen (DON), pH and soil moisture (SM), though the available P (aP) increased. Compared with no P treatment, alkaline phosphate and β-fructofuranosidase activities increased with P additions in the drought treatment. Drought decreased the total phospholipid-derived fatty acids (PLFAs), arbuscular mycorrhiza fungi (AMF), and fungi PLFAs compared to the well-watered. These findings indicated that P additions does not ameliorate the impact of drought on soil microbial communities and enzyme activities, except alkaline phosphate and β-fructofuranosidase, and P may not be responsible for regulating biochemical processes essential for maintaining the fertility of soil planted with P. zhennan under drought conditions. It is hypothesized that the lack of effects of P addition on the majority of the microbial properties could be due to the soil mechanism employed by P. zhennan to tolerate harsh conditions.

Keywords: Alkaline Phosphatase, Biomass, Drought, Enzymes, Microbial, Phoebe zhennan

iForest 11 (6): 751-756 (2018) - doi: 10.3832/ifor2725-011
https://iforest.sisef.org/contents/?id=ifor2725-011

Research Articles: Post-fire recovery of Abies cephalonica forest communities: the case of Mt Parnitha National Park, Attica, Greece

Christopoulou A, Kazanis D, Fyllas NM, Arianoutsou M — 2018-11-15

Christopoulou A, Kazanis D, Fyllas NM, Arianoutsou M

POST-FIRE RECOVERY OF ABIES CEPHALONICA FOREST COMMUNITIES: THE CASE OF MT PARNITHA NATIONAL PARK, ATTICA, GREECE

Abstract: Mountain coniferous forests of Southern Europe seem to be increasingly affected by large fires. Endemic Greek fir (Abies cephalonica) forests were among the most affected ecosystems by the 2007 extreme wildfires in Greece. The aim of this study is to investigate the pattern of post-fire regeneration of fir forest plant communities of Mount Parnitha National Park, in Attica (Greece), after a large wildfire. A network of 8 severely burned sites across the mountain ridge was established in order to monitor natural regeneration of A. cephalonica as well as post-fire floristic composition and species richness. Field campaigns took place in two distinct time periods, one close to the fire event and one 8 to 10 years after. Generalized linear models were used to explore the effects of distance and microhabitat variables on the post-fire regeneration of the Greek fir. Distance from the unburned patches, slope and cover of woody species significantly affected A. cephalonica seedling establishment and hence its natural post-fire regeneration. Floristic composition and plant species richness of the recovering fir communities changed through time. During the initial phase, high species richness was recorded, mainly because of the high contribution of herbaceous species. During the second period, species richness was lower and similar to that recorded in the unburned fir communities. It is during this period when the first seedlings of the Greek fir managed to establish, although their density is rather low to ensure full recovery of the forest.

Keywords: Greek Fir, Mountain Forests, Post-fire Regeneration, Vegetation Dynamics, Secondary Succession

iForest 11 (6): 757-764 (2018) - doi: 10.3832/ifor2744-011
https://iforest.sisef.org/contents/?id=ifor2744-011

Research Articles: Soil CO2 efflux in uneven-aged and even-aged Norway spruce stands in southern Finland

Kumpu A, Mäkelä A, Pumpanen J, Saarinen J, Berninger F — 2018-11-06

Kumpu A, Mäkelä A, Pumpanen J, Saarinen J, Berninger F

SOIL CO2 EFFLUX IN UNEVEN-AGED AND EVEN-AGED NORWAY SPRUCE STANDS IN SOUTHERN FINLAND

Abstract: Even-aged forests usually act as carbon sinks during most of their rotation. However, after clearcut they become sources of carbon for a period of several years. Applying uneven-aged forest management with selective cuttings will maintain tree cover and reduce the environmental impact on forest floor. The aim of this study was to compare the soil CO2 efflux between uneven-aged and even-aged Norway spruce stands with similar site properties, to investigate the effect of management practices on soil CO2 efflux and its possible correlation with soil environmental and chemical properties. We measured soil CO2 efflux in even- and uneven-aged Norway spruce stands (Picea abies [L.] Karst) in southern Finland during the summer of 2013 using closed chamber method on fixed measuring points. The study included two uneven-aged stands and two even-aged stands (a clearcut site and a mature even-aged stand). Soil moisture and soil temperature were measured at the same time as soil CO2 efflux. Soil cores were collected from the topsoil of each study plot to determine soil carbon and nitrogen concentrations. Mean soil CO2 efflux through the summer was highest in the clearcut plot (0.367 mg m-2 s-1) followed by the uneven-aged stands (0.298 and 0.257 mg m-2 s-1, respectively) and the smallest fluxes were measured in the mature even-aged stand (0.224 mg m-2 s-1). There was no statistically significant difference in soil CO2 efflux between the even- and uneven-aged stands of the same site fertility. Even- and uneven-aged stands did not differ significantly in soil moisture or soil temperature. Soil CO2 efflux increased steadily with soil temperature, whereas increasing soil moisture considerably increased soil CO2 efflux at lower moisture levels but only moderately at higher soil moisture levels. Soil carbon and nitrogen concentration did not differ between the study plots of the same fertility. Uneven-aged structure forestry did not prevent the increase in soil CO2 efflux after cuttings. However, the large variation in soil CO2 efflux rates within the uneven-aged stands suggests that the stand level CO2 efflux can be controlled with the intensity of the cutting.

Keywords: Uneven-aged Forest Structure, Even-aged Forest Structure, Soil CO2 Efflux, Norway spruce

iForest 11 (6): 705-712 (2018) - doi: 10.3832/ifor2658-011
https://iforest.sisef.org/contents/?id=ifor2658-011

Research Articles: Relationship between volatile organic compounds released and growth of Cunninghamia lanceolata roots under low-phosphorus conditions

Lai H, Wu K, Wang N, Wu W, Zou X, Ma X, Wu P — 2018-11-06

Lai H, Wu K, Wang N, Wu W, Zou X, Ma X, Wu P

RELATIONSHIP BETWEEN VOLATILE ORGANIC COMPOUNDS RELEASED AND GROWTH OF CUNNINGHAMIA LANCEOLATA ROOTS UNDER LOW-PHOSPHORUS CONDITIONS

Abstract: To understand whether Chinese fir (Cunninghamia lanceolata) can conserve energy by reducing root volatiles to maintain growth under low phosphorus (P) conditions, we cultivated two half-sib families of Chinese fir that display high and low P use efficiency under conditions of normal P supply and total P deficiency. Gas chromatography-mass spectrometry analysis was used to determine the content of root volatiles, and the relationships among root volatiles and root growth index, P content, and distribution were analyzed. There were significantly fewer volatile organic compounds (VOCs) in the rhizosphere of these two fir families, No. 25 and No. 32, under P deficiency. Low P supply significantly promoted root growth in No. 25, increasing both average diameter and volume. A negative correlation was found between the volatiles and the increment of root average diameter and surface area. The belowground P distribution and the root to shoot P concentration (Pr/Ps) were higher in No. 25 than in No. 32. The total amount of VOCs, as well as the amount of 18 individual volatiles were positively correlated with P accumulation, aboveground P distribution, and belowground P distribution, but the opposite pattern was seen in Pr/Ps for family No. 25 seedlings. We conclude that the content and types of VOCs differ among the Chinese fir genotypes. Under low-P stress, the roots of Chinese fir reduce the release of VOCs to maintain seedling growth.

Keywords: Cunninghamia lanceolata, Low-phosphorus Stress, Root Growth, Root Volatile Organic Compounds, Energy Balance

iForest 11 (6): 713-720 (2018) - doi: 10.3832/ifor2797-011
https://iforest.sisef.org/contents/?id=ifor2797-011

Research Articles: Distribution of aluminium fractions in acid forest soils: influence of vegetation changes

Pavlu L, Drabek O, Stejskalova S, Tejnecky V, Hradilova M, Nikodem A, Boruvka L — 2018-11-06

Pavlu L, Drabek O, Stejskalova S, Tejnecky V, Hradilova M, Nikodem A, Boruvka L

DISTRIBUTION OF ALUMINIUM FRACTIONS IN ACID FOREST SOILS: INFLUENCE OF VEGETATION CHANGES

Abstract: This study examines aluminium as a potentially phytotoxic element in acidic forest soils. Concentrations of Al forms in soils are generally controlled by soil chemical conditions, such as pH, organic matter, base cation contents, etc. Moreover, soil conditions are influenced by the vegetation cover. This study analyzed the distribution of Al forms in soils after changes in vegetation. HPLC/IC was used for the separation of three Al fractions in two soil extracts according to their charge. An aqueous extract (AlH2O) simulated the natural soil conditions and bioavailable Al fractions. Potentially available Al form was represented by a 0.5 M KCl extract (AlKCl). We demonstrated that the vegetation type influences the concentrations of different Al fractions, mainly in the surface organic horizons. Differences were more common in the KCl extract. The trivalent fraction was less influenced by vegetation changes than the mono- and divalent fractions. Afforestation increased the concentrations of AlKCl and AlH2O. In contrast, grass expansion after deforestation led to significantly decreased concentrations of AlKCl and AlH2O. Concentrations of AlH2O in organic horizons were higher in spruce forest than in beech forest. A long-term effect of liming on soil pH and concentrations of potentially toxic Al fractions was not apparent. The results provide information on the variations of Al fractions distributions following vegetation type changes and indicate the existence of some natural mechanisms controlling Al toxicity. Furthermore, the results can be used in the management of forested areas endangered by soil acidification.

Keywords: Aluminium Fractionation, Forest Soil, Afforestation, Deforestation, HPLC/IC

iForest 11 (6): 721-727 (2018) - doi: 10.3832/ifor2498-011
https://iforest.sisef.org/contents/?id=ifor2498-011

Research Articles: Drought tolerance in cork oak is associated with low leaf stomatal and hydraulic conductances

Rzigui T, Jazzar L, Baaziz Khaoula B, Fkiri S, Nasr Z — 2018-11-06

Rzigui T, Jazzar L, Baaziz Khaoula B, Fkiri S, Nasr Z

DROUGHT TOLERANCE IN CORK OAK IS ASSOCIATED WITH LOW LEAF STOMATAL AND HYDRAULIC CONDUCTANCES

Abstract: To investigate the role of seeds origin in drought tolerance, the response to water deprivation of cork oak seedlings differing in climatic conditions at their geographical origin was compared. Gaâfour is the provenance from the driest site and Feija is the provenance from the wettest site. Net photosynthesis (An), stomatal conductance (gs) and leaf water potential were measured during dehydration. A delayed decrease in leaf water potential is observed after water withholding in Gaâfour as compared to Feija leaves. At the onset of dehydration, An and gs were higher in Feija. After withholding watering, Gaâfour leaves were able to maintain a higher An and gs than Feija leaves. Most likely, drought tolerance in Gaâfour leaves is associated to their lower gs under well-hydrated conditions. The stomatal density (Ds) and specific leaf area (SLA) were not different in well-watered leaves but, leaf hydraulic conductance was lower in Gaâfour leaves when compared to Feija leaves. Our results suggested that lower stomatal and hydraulic conductances of Gaâfour leaves could be involved in bringing about the better resistance to dehydration.

Keywords: Drought, Cork Oak, Photosynthesis, Stomatal Conductance, Hydraulic Conductance

iForest 11 (6): 728-733 (2018) - doi: 10.3832/ifor2749-011
https://iforest.sisef.org/contents/?id=ifor2749-011

Research Articles: Dynamics of soil organic carbon (SOC) content in stands of Norway spruce (Picea abies) in central Europe

Becvárová P, Horváth M, Sarapatka B, Zouhar V — 2018-11-06

Becvárová P, Horváth M, Sarapatka B, Zouhar V

DYNAMICS OF SOIL ORGANIC CARBON (SOC) CONTENT IN STANDS OF NORWAY SPRUCE (PICEA ABIES) IN CENTRAL EUROPE

Abstract: Norway spruce is the main forest tree species in the Czech Republic. Until now, little attention has been given in the literature to the dynamics of soil organic carbon (SOC) content under Norway spruce stands as a function of stand characteristics. The aim of this study is to estimate soil organic carbon (SOC) content and stock changes in organic and surface mineral soil horizons on forest sites with a dominant representation of Norway spruce. In the study area, a significantly higher content of SOC was found in the surface mineral soil horizon than in the organic soil horizon. In both soil horizons, there was evidence of an increasing trend of SOC with the increasing age of forest stands, a decreasing trend of SOC with increasing density of stocking and an increasing trend of SOC with increasing altitude. The relationship of SOC content with soil group (Podzol vs. non-Podzol) has also been demonstrated. The greatest potential for long-term carbon sequestration in soils was shown in older stands (101-190 years) dominated by Norway spruce with lower density of stocking, located in forest vegetation zones (1010-1225 m a.s.l.) where natural mountain Norway spruce forests currently occur. According to our results, Norway spruce stands may perform a stable function of carbon sequestration in the soil at these sites, especially in the mineral soil horizon.

Keywords: Forest Soil, C Sequestration, Picea abies, Site Conditions, Stand Characteristics, Climate Change

iForest 11 (6): 734-742 (2018) - doi: 10.3832/ifor2521-011
https://iforest.sisef.org/contents/?id=ifor2521-011

Research Articles: Short- and long-term natural regeneration after windthrow disturbances in Norway spruce forests in Bulgaria

Tsvetanov N, Dountchev A, Panayotov M, Zhelev P, Bebi P, Yurukov S — 2018-10-23

Tsvetanov N, Dountchev A, Panayotov M, Zhelev P, Bebi P, Yurukov S

SHORT- AND LONG-TERM NATURAL REGENERATION AFTER WINDTHROW DISTURBANCES IN NORWAY SPRUCE FORESTS IN BULGARIA

Abstract: Norway spruce forests are among the forests most affected by natural disturbances in Europe. One of the key aspects is the regeneration of the disturbed areas, which is decisive for later forest development. We studied the natural regeneration after two windthrows that occurred 30 (1983) and 50 years ago (1962) in an old-growth forest over 150-year-old in the Parangalitsa Reserve and a recent windthrow (2001) in a 130-year-old single cohort forest in the Bistrishko branishte Reserve in Bulgaria. We set up study plots along transects, counted regeneration and substrates, and analyzed age using tree rings. Post-disturbance regeneration made up 62-81% of all recorded trees and was more important than advance regeneration, but it strongly differed among the windthrows. Our data indicated two discrete peaks of post-disturbance regeneration. The first peak started immediately after the windthrows and was dominated by Norway spruce and rowan, while the second one started about 30 years later and was dominated by spruce. Pioneers such as Populus tremula, Salix caprea and Pinus sylvestris were less prominent than expected, contributing up to 21% of the total regeneration. Despite the fact that the highest density of initial regeneration was found on mounds from uprooted trees, the largest total number in the three studied areas was on intact forest floor, which hosted between 69 and 80% of all regeneration. The importance of coarse woody debris rose significantly two to three decades after the disturbances and was particularly important for the secondary regeneration, which consisted of Picea abies and Abies alba.

Keywords: Picea abies, Natural Regeneration, Windthrows, Natural Disturbances, Southeastern Europe

iForest 11 (5): 675-684 (2018) - doi: 10.3832/ifor2754-011
https://iforest.sisef.org/contents/?id=ifor2754-011

Research Articles: What if Eurasian jay Garrulus glandarius would larder acorns instead of scatter them?

Kurek P, Dobrowolska D, Wiatrowska B, Dylewski L — 2018-10-23

Kurek P, Dobrowolska D, Wiatrowska B, Dylewski L

WHAT IF EURASIAN JAY GARRULUS GLANDARIUS WOULD LARDER ACORNS INSTEAD OF SCATTER THEM?

Abstract: Jays usually store acorns at separate sites, but in some cases a part of jay’s caches consists of more than one acorn. Storing acorns separately (scatter hoarding) or in clusters (larder hoarding) seems to be an important factor for further survival of seeds and seedlings. Scatter hoarding is favorable for jays, but what would happen if jays prepared caches consisting of more than one acorn? We put a following question: what is the importance and impact of acorn concentration per cache for the seedlings’ mortality and their growth characteristics? In 2013 an experimental plot was established. 1400 acorns of Quercus robur L. were sewed in 600 holes in three combinations called growing mode - singly, in twos and in fours. The mortality of seedlings depended on growing mode (Z = 6.24, P < 0.001) and year (Z = -2.42, P = 0.016). In the third year of the experiment the mortality of seedlings growing from acorns sewed in fours reached almost 90%, while in the case of seedlings growing separately the mortality was stable, reaching no more than 23%. Both growing mode (F = 26.49, P < 0.001) and year (F = 52.59, P < 0.001) had a significant impact on seedling growth increment. Seedlings growing in fours had a significantly higher growth increment than these growing separately and in twos. We concluded that seedlings growing separately had a higher survival rate, but lower growth increment than those coming from acorns sewed in clumps.

Keywords: Eurasian Jay, Acorns, Scatter Hoarding, Larder Hoarding, Seedlings Survival, Seed Dispersal

iForest 11 (5): 685-689 (2018) - doi: 10.3832/ifor2793-011
https://iforest.sisef.org/contents/?id=ifor2793-011

Research Articles: The effect of silver and copper nanoparticles on the growth and mycorrhizal colonisation of Scots pine (Pinus sylvestris L.) in a container nursery experiment

2018-10-23

Aleksandrowicz-Trzcinska M, Szaniawski A, Studnicki M, Bederska-Blaszczyk M, Olchowik J, Urban A

THE EFFECT OF SILVER AND COPPER NANOPARTICLES ON THE GROWTH AND MYCORRHIZAL COLONISATION OF SCOTS PINE (PINUS SYLVESTRIS L.) IN A CONTAINER NURSERY EXPERIMENT

Abstract: Recent research points to the possibility of nanoparticles being used as fertilisers, growth stimulators, and promoters of plant resistance or pesticides. In this study, we sought to determine the influence of nanoparticles of silver and copper (AgNPs and CuNPs) on growth parameters and spontaneous mycorrhizal colonisation of roots in 2-year-old container-grown seedlings of Scots pine. Foliar applications of nanoparticles were made through two growing seasons, four times a season, at concentrations of 0, 5, 25 and 50 ppm. Comparisons of the ultrastructures characterising the needles, stems and roots of the treated or untreated pines were conducted with transmission electron microscopy (TEM). The deployed CuNPs stimulated mycorrhizal colonisation at all concentrations, although the growth of seedlings was only promoted at a concentration of 25 ppm. Higher concentrations of AgNPs (25 and 50 ppm) inhibited the formation of mycorrhizae, though the lowest concentration (5 ppm) produced an increase in both mycorrhizal colonisation and the dry mass of roots. The species of ectomycorrhizal fungi found were Thelephora terrestris, Suillus bovinus and Sphaerosporella brunnea. The TEM results comparing treated and control (untreated) needles revealed changes in the chloroplasts from lens-shaped to spherical. Furthermore, an increase in the number of plastoglobules and the presence of large osmophilic globules in the cytoplasm associated solely with the needles of pines receiving 50 ppm nanoparticles were observed. In contrast, ultrastructural changes in stems and roots associated with the applications of NPs were not found. Overall, the results indicated that CuNPs and AgNPs could be used as stimulators of growth in general, and mycorrhizal colonisation in particular, among container-grown Scots pines. However, further work is needed to determine their optimal doses and concentrations.

Keywords: Nanoparticles, Ectomycorrhizae, Toxicity, Growth Stimulation

iForest 11 (5): 690-697 (2018) - doi: 10.3832/ifor2855-011
https://iforest.sisef.org/contents/?id=ifor2855-011

Research Articles: Managed and unmanaged silver fir-beech forests show similar structural features in the western Pyrenees

Horvat V, García De Vicuña J, Biurrun I, García-Mijangos I — 2018-10-23

Horvat V, García De Vicuña J, Biurrun I, García-Mijangos I

MANAGED AND UNMANAGED SILVER FIR-BEECH FORESTS SHOW SIMILAR STRUCTURAL FEATURES IN THE WESTERN PYRENEES

Abstract: Forest structure is considered one of the basic features of the forest ecosystem and it is widely studied with the aim of developing sustainable management strategies. The usual approach is to compare structural features of stands in managed and unmanaged forests. Managed stands are those disturbed in some way by silvicultural practices, whereas unmanaged stands are subject to natural disturbance dynamics and may serve as a reference. Up to now, there has been insufficient research into sustainable management strategies for Pyrenean silver fir-beech forests and the structure of managed and unmanaged stands has not yet been evaluated. The aim of this study is to provide a detailed characterisation of the structural attributes of these mixed mountain forests in the western Pyrenees and compare managed and unmanaged stands regarding selected stand parameters. Potential differences between managed and unmanaged stands were assessed with Mann-Whitney U-tests. Diameter distribution was modelled using third-order polynomials and non-linear regression was performed to compare the tree heights in managed and unmanaged stands. Stand structure was similar in both management categories. The diameter distribution of Pyrenean unmanaged silver fir-beech stands showed a tendency towards a rotated sigmoid distribution. Our results indicate that the recommended diameter distribution has been preserved in managed stands despite they were intensively managed in the past, whilst the unmanaged stands are still in the process of developing old-growth attributes because management was abandoned too recently for significant changes in forest structure to have occurred.

Keywords: Forest Management, Gaps, Pyrenees, Stand Structure

iForest 11 (5): 698-704 (2018) - doi: 10.3832/ifor2720-011
https://iforest.sisef.org/contents/?id=ifor2720-011

Research Articles: Effects on soil characteristics by different management regimes with root sucker generated hybrid aspen (Populus tremula L. × P. tremuloides Michx.) on abandoned agricultural land

Rytter RM, Rytter L — 2018-10-04

Rytter RM, Rytter L

EFFECTS ON SOIL CHARACTERISTICS BY DIFFERENT MANAGEMENT REGIMES WITH ROOT SUCKER GENERATED HYBRID ASPEN (POPULUS TREMULA L. × P. TREMULOIDES MICHX.) ON ABANDONED AGRICULTURAL LAND

Abstract: Fast-growing Populus species are becoming frequently used at afforestation of arable land globally and hybrid aspen is promising for short rotation forestry in the northern hemisphere. Knowledge about growth performance of the second-generation plantations, i.e., consisting of root sucker generated shoots after clearcutting of the original stand, is increasing, but less information is available on the effects on soil properties, especially with varying management. We followed the soil effects of three different management regimes, including 4-, 8- and 16-year rotations with thinning measures in the two longer rotations, in root sucker generated hybrid aspen on former agricultural land. The study was performed in a randomized block design and changes in soil variables were estimated by repeated sampling, i.e., at root sucker initiation and after eight years. Concentrations and pools of soil organic carbon (SOC) and soil nutrients, pH and bulk density were analysed in the 0-15 and 15-30 cm mineral soil. Common for all management regimes were unchanged SOC and nutrient pools; pH and bulk density were also unaffected during the study period. Afforestation effects on the vertical distribution of nutrients, i.e., redistribution of NH4-N, K and Mg from deeper to shallower soil by plant uptake and release through litter decomposition, were observed in all management regimes. A different effect was noted for NO3-N where a declining trend was observed. This could indicate a leakage of the ion, but NO3-N distributions in soils are variable which makes interpretations difficult. The results suggest that different management strategies have small initial effects on mineral soil characteristics. However, soil changes need to be followed for an extended period to get more information on the long-term impact of afforestation and management of root sucker generated stands.

Keywords: Afforestation, Bulk Density, Nutrient Removal, pH, Rotation Time, Soil Organic Carbon (SOC), Soil Nutrients

iForest 11 (5): 619-627 (2018) - doi: 10.3832/ifor2853-011
https://iforest.sisef.org/contents/?id=ifor2853-011

Research Articles: The spread of the non-native pine tortoise scale Toumeyella parvicornis (Hemiptera: Coccidae) in Europe: a major threat to Pinus pinea in Southern Italy

Garonna AP, Foscari A, Russo E, Jesu G, Somma S, Cascone P, Guerrieri E — 2018-10-04

Garonna AP, Foscari A, Russo E, Jesu G, Somma S, Cascone P, Guerrieri E

THE SPREAD OF THE NON-NATIVE PINE TORTOISE SCALE TOUMEYELLA PARVICORNIS (HEMIPTERA: COCCIDAE) IN EUROPE: A MAJOR THREAT TO PINUS PINEA IN SOUTHERN ITALY

Abstract: Invasive pests are considered a major threat to biodiversity, conservation and agriculture. The Italian peninsula is a major site of intensive commercial exchange and transport of plants and goods, being consequently one of the European countries most invaded by alien insects. Hemiptera Coccomorpha are the largest group of non-native species recorded in Europe. For example, in the last 70 years more than 50 scale insect species have been accidentally introduced into Italy, 50% of which are now well established. This study was conducted to investigate the biology and the damage of the non-native pine tortoise scale Toumeyella parvicornis Cockerell (Hemiptera: Coccidae) accidentally introduced a few years ago into southern Italy. T. parvicornis is multivoltine in the invaded territories, being able to complete at least three generations per year, overwintering in the adult female stage. Oviposition periods during 2015-2017 surveys occurred from late April to end of May, from July to first half of August, and from mid-September to November. Fecundity was positively correlated to body size of gravid females and varied among the generations. Investigations on natural control by autochthonous species showed a seasonal activity of Metaphycus flavus (Hymenoptera: Encyrtidae), parasitizing mainly immature male individuals. The morpho-molecular approach confirms the hypothesis of an ongoing shift of parasitoid populations from other indigenous soft scales to the invasive one. Unfortunately, the low level of natural control was ineffective in hampering the spread of T. parvicornis, and preventing the dieback of local pine species, Pinus pinea, as observed in all invaded areas.

Keywords: Invasive Pest, Europe, Toumeyella parvicornis, Life History, Pinus pinea, Natural Control

iForest 11 (5): 628-634 (2018) - doi: 10.3832/ifor2864-011
https://iforest.sisef.org/contents/?id=ifor2864-011

Research Articles: Post-fire recovery of the plant community in Pinus brutia forests: active vs. indirect restoration techniques after salvage logging

Ürker O, Tavsanoglu &, Gürkan B — 2018-10-04

Ürker O, Tavsanoglu &, Gürkan B

POST-FIRE RECOVERY OF THE PLANT COMMUNITY IN PINUS BRUTIA FORESTS: ACTIVE VS. INDIRECT RESTORATION TECHNIQUES AFTER SALVAGE LOGGING

Abstract: Although reforestation is frequently utilized in many Mediterranean Basin countries to restore burned Mediterranean pine woodlands, post-fire recovery of the plant community is often neglected. To compare the post-fire recovery of the plant community following active and indirect post-fire restoration techniques, we studied three post-fire regeneration treatments in a salvage-logged Pinus brutia forest, including two active (plantation and seeding) restoration techniques and one indirect (natural regeneration). An unburned pine stand was also included in the study. We applied the point-intercept method to obtain data on the presence and cover of individual species and functional groups in six replicate one-hectare plots for each treatment. We found no significant differences in plant species richness among post-fire treatments; however, plant community composition and vegetation structure were significantly different between treatments. There was a shift in plant community structure when active restoration techniques were applied, from the woody- and resprouter-dominated plant community of the unburned site to an annual herbaceous- and non-resprouter-dominated one. Our results suggest that active restoration by planting tree saplings in Mediterranean pine forests after a fire may decrease the plant community’s resilience and provide empirical evidence that pine plantation treatments change the plant species composition of these forests. These results have important implications for post-fire management of Mediterranean Basin pine forests.

Keywords: Fire, Mediterranean Pine Forest, Plant Cover, Plant Functional Groups, Post-fire Restoration, Resilience, Species Diversity, Turkish Red Pine

iForest 11 (5): 635-642 (2018) - doi: 10.3832/ifor2645-011
https://iforest.sisef.org/contents/?id=ifor2645-011

Research Articles: Predicting the impacts of climate change on the distribution of Juniperus excelsa M. Bieb. in the central and eastern Alborz Mountains, Iran

Fatemi SS, Rahimi M, Tarkesh M, Ravanbakhsh H — 2018-10-04

Fatemi SS, Rahimi M, Tarkesh M, Ravanbakhsh H

PREDICTING THE IMPACTS OF CLIMATE CHANGE ON THE DISTRIBUTION OF JUNIPERUS EXCELSA M. BIEB. IN THE CENTRAL AND EASTERN ALBORZ MOUNTAINS, IRAN

Abstract: In recent years, global climate change has had significant biological, temporal, and spatial effects on many terrestrial habitats. The objective of this study was to evaluate the effect of climate change on the geographic distribution of Juniperus excelsa and prioritize its habitats for protection against these effects until 2070. The study was conducted using the MaxEnt species distribution model and two data series GFDL-CM3 and MRI-CGCM3 under scenarios RCP2.6 and RCP4.5 of the 5th IPCC report. Our results revealed that elevation, minimum temperature of coldest month, precipitation of coldest quarter, annual mean temperature, and slope aspect, in that order, have the greatest effects on the species’ distribution in the study area. Under optimistic scenario RCP2.6, both models predicted that the species’ presence area will grow, but under RCP4.5, models predicted that by 2070, some parts of its habitat in western and central heights will be lost because of change in climate parameters like minimum temperature of coldest month and precipitation of coldest quarter. Under the latter scenario, the northeastern parts of the study area showed no changes in terms of climatic parameters and climatic niche. The results of both climate data series indicated that the Juniperus excelsa will slowly migrate to higher elevations to cope with the changing climate. Assessment of the results through field studies showed that outputs of GFDL-CM3 are closer to the reality.

Keywords: Juniperus excelsa, Climate Change, Irano-Turanian Forests, MaxEnt Model, Climatic Niche

iForest 11 (5): 643-650 (2018) - doi: 10.3832/ifor2559-011
https://iforest.sisef.org/contents/?id=ifor2559-011

Research Articles: Delineation of seed collection zones based on environmental and genetic characteristics for Quercus suber L. in Sardinia, Italy

De Dato G, Teani A, Mattioni C, Marchi M, Monteverdi MC, Ducci F — 2018-10-04

De Dato G, Teani A, Mattioni C, Marchi M, Monteverdi MC, Ducci F

DELINEATION OF SEED COLLECTION ZONES BASED ON ENVIRONMENTAL AND GENETIC CHARACTERISTICS FOR QUERCUS SUBER L. IN SARDINIA, ITALY

Abstract: The assessment of seed zones or regions of provenance (RoP) to preserve local adaptation of tree species is an effective tool for the correct management of forest reproductive materials. The RoP for a species or sub-species is the area or group of areas subject to sufficiently uniform ecological conditions in which stands or seed sources show similar phenotypic or genetic characters, taking into account altitudinal boundaries where appropriate. However, the delineation of RoPs is commonly based on estimates of intrinsic environmental homogeneity, mainly climate and/or soil characteristics. The integration of genetic data into RoP maps is an important strategy to obtain a sound tool for managing forest reproductive materials. A study on Quercus suber (cork oak) in Sardinia (Italy) was carried out with the aim of determining ecological regions of provenance, investigating the genetic diversity among populations at the regional scale and identifying possible areas of interest for valorising the available germplasm. Identification of these areas was performed by Reserve Selection Analysis, which allows to identify priority areas by assessing the minimum number of sites required to include all the genetic diversity estimated by genetic analysis. Four spatial clusters were obtained based on environmental data: the northern and northern-eastern parts of the island were included in the Northern RoP; the second RoP covered the western part; and the third RoP enclosed the south-eastern region. The last group was distributed on the central part of the island (Central RoP) and includes the higher elevations. The sampled populations showed a low differentiation among populations and low diversity. According to the Reserve Selection Analysis, four conservation priority areas were identified. These indications can be useful at the local level because these sites can be proposed as stands for seed collection for future plantations.

Keywords: Regions of Provenance, Quercus suber, Seed Collection Zones, Spatial Genetic Structure, Sardinia

iForest 11 (5): 651-659 (2018) - doi: 10.3832/ifor2572-011
https://iforest.sisef.org/contents/?id=ifor2572-011

Research Articles: Towards the economic valuation of ecosystem production from cork oak forests in Sardinia (Italy)

Corona P, Quatrini V, Schirru M, Dettori S, Puletti N — 2018-10-04

Corona P, Quatrini V, Schirru M, Dettori S, Puletti N

TOWARDS THE ECONOMIC VALUATION OF ECOSYSTEM PRODUCTION FROM CORK OAK FORESTS IN SARDINIA (ITALY)

Abstract: A spatially explicit approach for stand-scale economic valuation of current and future potential of cork forests with respect to ecosystem production is developed and presented. The approach, which relies in large part on the mensuration of stand top height and number of trees as main drivers, has been tested on the pure cork forests of Sardinia (Italy). The test was conducted to assess the effects of alternative silvicultural options on cork and fodder production, carbon sequestration, and water yield. Under current conditions, the surveyed pure cork oak forest stands in Sardinia are characterized, on average, by an annual economic production of 93 euro ha-1 yr-1 as concerns cork, 37 euro ha-1 yr-1 as concerns carbon sequestration and 261 euro ha-1 yr-1 as concerns water yield. The value of cork production on an 11-year cycle equals 1023 euro ha-1 on average. The total economic production values among the tested silvicultural alternatives have proven to be characterized by relatively small differences, due to the trade-offs among the considered goods and services. Therefore, at least under conditions similar to those surveyed, managers may safely rely on different stand density options, without any relevant detrimental effect on total economic production. The tested spatial visualization of the economic values of goods and services production can be useful in supporting forest management planning, e.g., to identify priority areas in order to maximize ecosystem production for local communities. The approach proposed here and tested to this end proves to be readily applicable to other cork contexts with similar characteristics under Mediterranean conditions.

Keywords: Forest Management, Cork Production, Fodder Production, Carbon Sequestration, Water Yield

iForest 11 (5): 660-667 (2018) - doi: 10.3832/ifor2558-011
https://iforest.sisef.org/contents/?id=ifor2558-011

Research Articles: Indicators for the assessment and certification of cork oak management sustainability in Italy

Pollastrini M, Chiavetta U, Cutini A, Casula A, Maltoni S, Dettori S, Corona P — 2018-10-04

Pollastrini M, Chiavetta U, Cutini A, Casula A, Maltoni S, Dettori S, Corona P

INDICATORS FOR THE ASSESSMENT AND CERTIFICATION OF CORK OAK MANAGEMENT SUSTAINABILITY IN ITALY

Abstract: Sustainable forest management (SFM) is crucial for forest ecosystem productivity and conservation, especially in systems such as cork oak (Quercus suber L.) threatened by human activities and biotic and abiotic factors. In this study SFM indicators with particular reference to cork oak forests in the region of Sardinia (Italy) are proposed and tested. Sustainable and responsible management options specifically aimed at cork oak forest management and chain of custody certification are also provided. A set of ten indicators was proposed and assessed by an expert panel in cork oak management. Five indicators were also tested against data on structure, origin, health condition and management in 285 forest compartments managed by FoReSTAS (Regional Forest Agency for Land and Environment of Sardinia, Italy), including 361 sampling plots and 5345 trees. In order to investigate the priorities and perceptions of SFM experts and stakeholders, a survey was also carried out by completion of a questionnaire on the technical issues of cork oak woodland management. The survey results highlighted a need to improve environmental and economic performance by means of SFM and certification. The indicators tested in Sardinian cork oak woodlands showed that about 80% of the stands fulfilled management sustainability requirements. The suggested SFM indicators can effectively support proactive management and conservation measures, representing a valuable tool in the current context of growing environmental and socioeconomic awareness.

Keywords: Quercus suber, Sustainable Forest Management, Forest Management Planning, Non-wood Forest Products, Sardinia, Italy

iForest 11 (5): 668-674 (2018) - doi: 10.3832/ifor2587-011
https://iforest.sisef.org/contents/?id=ifor2587-011

Review Papers: Perspective on the control of invasive mesquite trees and possible alternative uses

Ellsworth SW, Crandall PG, Lingbeck JM, O’Bryan CA — 2018-09-25

Ellsworth SW, Crandall PG, Lingbeck JM, O’Bryan CA

PERSPECTIVE ON THE CONTROL OF INVASIVE MESQUITE TREES AND POSSIBLE ALTERNATIVE USES

Abstract: Mesquite trees continue to invade forests and range lands in many countries across the world. The cost to remove these trees is staggering. In Texas, landowners spent $25 million over a 10-year period to clear 300.000 ha of mesquite trees, a fraction of the 22 million ha of Texas land affected by this invasion. Estimates are that the mesquite continues to negatively impact one to two percent of additional land in selected counties each year in Texas. However, the problem is not unique to Texas, but rather to the 44 species of mesquite trees, belonging to the genus Prosopis found in the pea family (Fabaceae), introduced across the southern United States, South Asia, Africa, the Middle East, South America, and the Caribbean. In response, researchers are searching for economically viable uses for harvested trees and seeds to provide an alternative to the high cost of removal. If viable uses for harvested mesquite trees and seeds are found, then sustained pressure will limit and ultimately reduce the negative impact from these invasive trees. One key factor to controlling this invasive species is to find economically and environmentally sustainable uses to help pay the costs of removal or perhaps make removal less necessary. Traditional uses of mesquite are as a building material, as a source of food for both animals and humans and as wood for charcoal. Emerging uses of mesquite are new applications as a biofuel and as a bio-filter medium for water. Moreover, forestry land management of mesquite has adapted to include the tree as a component of hunting lands. New control methodologies and technologies are based on an increased understanding of mesquite growth patterns, using recommended practices that reduce control and eradication costs while improving the efficiency of land management. Previous land management practices have proven that excessive application of herbicides, physical removal of mesquite trees, or human-induced brush fires, if not carefully planned, only worsen mesquite infestations. The growing problem of mesquite land management provides an opportunity for continued research into novel ways to utilize mesquite biomass, of both wood and seed pods.

Keywords: Mesquite, Land Management, Prosopis spp., Biofuel

iForest 11 (5): 577-585 (2018) - doi: 10.3832/ifor2456-011
https://iforest.sisef.org/contents/?id=ifor2456-011

Research Articles: Exploring patterns, drivers and structure of plant community composition in alien Robinia pseudoacacia secondary woodlands

Campagnaro T, Nascimbene J, Tasinazzo S, Trentanovi G, Sitzia T — 2018-09-25

Campagnaro T, Nascimbene J, Tasinazzo S, Trentanovi G, Sitzia T

EXPLORING PATTERNS, DRIVERS AND STRUCTURE OF PLANT COMMUNITY COMPOSITION IN ALIEN ROBINIA PSEUDOACACIA SECONDARY WOODLANDS

Abstract: Invasive alien tree species can strongly impact biodiversity and future projections predict their spread over natural, semi-natural and human habitats. However, little is known about plant communities that form during the first stages of invasion. We investigated the composition of plant communities in alien Robinia pseudoacacia L. secondary forests growing on grasslands and cultivated areas abandoned during the last 35-40 years in north-eastern Italy to understand whether these formations could cause floristic homogenization of plant communities composition. On the basis of a cluster analysis, plant communities were assigned to seven syntaxonomic categories and split into four groups characterized by the occurrence of 20 species indicative of (a) nitrogen-rich, (b) true forest and (c) open habitat conditions. RDA analysis enabled main stand and environmental variables filtering these communities to be identified and β-diversity components were partitioned through the SDR (Similarity - richness Difference - species Replacement) simplex approach. Plant composition patterns were significantly associated to variability in elevation, stand vertical structure, shrub cover, mean tree diameter and height, and basal area. Shrub cover discriminates between plant communities associated with open or shaded conditions. The partition of β-diversity components revealed that replacement is the prominent process structuring plant communities in these secondary forests. Our study showed that secondary Robinia forests growing on abandoned lands may host compositionally heterogeneous plant communities, thus contributing to regional biodiversity.

Keywords: Black Locust, Alien Tree Species, Biological Invasion, Species Replacement, Plant Composition

iForest 11 (5): 586-593 (2018) - doi: 10.3832/ifor2687-011
https://iforest.sisef.org/contents/?id=ifor2687-011

Short Communications: Shrub encroachment alters topsoil C:N:P stoichiometric ratios in a high-altitude forest cutover

Feng D, Bao W — 2018-09-25

Feng D, Bao W

SHRUB ENCROACHMENT ALTERS TOPSOIL C:N:P STOICHIOMETRIC RATIOS IN A HIGH-ALTITUDE FOREST CUTOVER

Abstract: The effect of shrub encroachment on soil carbon (C): nitrogen (N): phosphorus (P) stoichiometric ratios are largely still unknown. We investigated this effect and the effect of shrub size in a high altitude forest cutover among four common shrub species: Cerasus trichostoma, Ribes glaciale, Rosa omeiensis and Salix sphaeronymphe. The difference in topsoil C:N ratio between meadows and shrub islands was greatly influenced by shrub species and plant sizes. Topsoil N:P and C:P ratios were always higher in shrub islands than in meadows, irrespective of shrub species and plant size. The expansion of shrubs merely increased the topsoil C:N ratio beneath Cerasus and Rosa, and increased the topsoil N:P and C:P ratios beneath the four shrub species. The increase in stoichiometric ratio followed an identical pattern among the four shrub species as shrub size increased. There were always higher topsoil C:P and N:P ratios beneath Ribes than under the other shrub species with the same plant size. This study clearly suggests that the effect of shrub islands on soil C:N:P stoichiometric ratios was dependent on shrub species and size. Our results are conducive to clarifying the currently confusion in secondary successional trends of soil C:N:P stoichiometry.

Keywords: Plant Species, Shrub Islands, Shrub Size, Soil Stoichiometry

iForest 11 (5): 594-599 (2018) - doi: 10.3832/ifor2803-011
https://iforest.sisef.org/contents/?id=ifor2803-011

Research Articles: Changes in the properties of grassland soils as a result of afforestation

Podwika M, Solek-Podwika K, Ciarkowska K — 2018-09-25

Podwika M, Solek-Podwika K, Ciarkowska K

CHANGES IN THE PROPERTIES OF GRASSLAND SOILS AS A RESULT OF AFFORESTATION

Abstract: The effects of afforestation on physical, physico-chemical, and biological properties of grassland soils were investigated in three sites (215-230 m a.s.l.) located within the urban area of Krakow (southern Poland) after 45-60 years since the introduction of forest tree species. We compared the contents of nutrients and the composition of humus between forest and adjacent grassland soils, as well as the quality of the forest soils in relation to the introduced tree species (alder, pine, oak, birch, maple, elm). We hypothesized that afforestation of grassland soils results in the increase of acidity and nutrient contents. Studied soils belong to Dystric Gleysols (forest) and Eutric Gleysols (grassland). Overall, 168 soil samples were taken from two layers (0-10 cm and 10-30 cm) both from forest and grassland soils. The results showed an increase of organic carbon (up to 150%), total nitrogen (up to 70%) and total acidity (up to 18 times), as well as a decrease of pH (up to 40%) and activity of dehydrogenase (up to 60%) in forest soils in relation to the respective grassland soils. The most intensive changes were observed in the topsoil layers (0-10 cm). We also calculated the Soil Quality index (SQI) based on PCA in which only soil parameters with high load factors were taken into consideration. SQI ranged from 0.39 to 0.41 in grassland soils and from 0.33 to 0.37 in forest soils. Among forest soils, the highest value of SQI was obtained for stands dominated by black alder, indicating that such species is the most suitable for afforestation purposes under the study conditions. The results may be helpful in the realization of afforestation plans of humid grassland soils.

Keywords: Land Use Change, Physico-chemical Soil Properties, Soil Quality Index

iForest 11 (5): 600-608 (2018) - doi: 10.3832/ifor2556-011
https://iforest.sisef.org/contents/?id=ifor2556-011

Research Articles: Early responses of biodiversity indicators to various thinning treatments in mountain beech forests

2018-09-25

Lombardi F, Lella SD, Altieri V, Benedetto SD, Giancola C, Lasserre B, Kutnar L, Tognetti R, Marchetti M

EARLY RESPONSES OF BIODIVERSITY INDICATORS TO VARIOUS THINNING TREATMENTS IN MOUNTAIN BEECH FORESTS

Abstract: In recent decades, the conservation of biodiversity has become one of the main areas under consideration in managing forests in an ecologically sustainable way. Forest management practices are primary drivers of diversity and may enhance or decrease forest biodiversity, according to the measures applied (thinning options). We have focused on three beech (Fagus sylvatica L.) forests across a latitudinal gradient in Italy, characterised by different structures resulting from dissimilar management. We tested the short-term effects of differently-based silvicultural intervention vs. stands where no silvicultural practices were applied on biodiversity indicators and related proxies: deadwood amounts, microhabitat density, floristic richness and life form abundance. In each study area, the occurrence of the above indicators and proxies was evaluated before and after the implementation of crop tree thinning (CTT) and thinning from below (LT) methods, comparing them with control areas where no interventions were performed. After two years, the management options resulted in different responses of the investigated parameters. The CTT increased deadwood amounts in comparison with the LT ones, while stumps increased significantly after the LT thinning. Microhabitats increased significantly where intervention was not undertaken. On the contrary, they remained unaltered after the LT treatments. CTT thinning created favourable conditions for the development of microhabitats and their proliferation in the long term. Two years after the application of the CTT thinning treatment, all forest stands demonstrated a significant increase in their floristic richness and herb layer cover. Significant differences were also found in both the frequency and cover of life forms in relation to silvicultural treatment. These findings provide a better understanding of short-term effects of silvicultural treatment useful for maintaining biodiversity in mountain beech forests.

Keywords: Deadwood, Microhabitats, Understory Vegetation, Mountain Forests, Sustainable Forest Management, Italian Forests

iForest 11 (5): 609-618 (2018) - doi: 10.3832/ifor2733-011
https://iforest.sisef.org/contents/?id=ifor2733-011

Research Articles: Bayesian geographically weighted regression and its application for local modeling of relationships between tree variables

Subedi N, Zhang L, Zhen Z — 2018-09-01

Subedi N, Zhang L, Zhen Z

BAYESIAN GEOGRAPHICALLY WEIGHTED REGRESSION AND ITS APPLICATION FOR LOCAL MODELING OF RELATIONSHIPS BETWEEN TREE VARIABLES

Abstract: Geographically weighted regression (GWR) has become popular in recent years to deal with spatial autocorrelation and heterogeneity in forestry and ecological data. However, researchers have realized that GWR has some limitations, such as correlated model coefficients across study areas, strong influence of outliers, weak data problem, etc. In this study, we applied Bayesian geographically weighted regression (BGWR) and a robust BGWR (rBGWR) to model the relationship between tree crown and diameter using observed tree data and simulated data to investigate model fitting and performance in order to overcome some limitations of GWR. Our results indicated that, for observed tree data, the rBGWR estimated tree crown more accurate than both BGWR and GWR. For the simulated data, 74.1% of the estimated slope coefficients by rBGWR and 73.4% of the estimated slope coefficients by BGWR were not significantly different (α = 0.05) from the corresponding simulated slope coefficients. The estimation of model coefficients by rBGWR was not sensitive to outliers, but the coefficient estimation by GWR was strongly affected by those outliers. The majority of the coefficient estimates by rBGWR and BGWR for weak observations were not significantly (α = 0.05) different from the simulated coefficients. Therefore, BGWR (including rBGWR) may be a better alternative to overcome some limitations of GWR. In addition, both BGWR and rBGWR were more powerful than GWR to detect the spatial areas with non-constant variance or spatial outliers.

Keywords: Spatial Autocorrelation, Spatial Heterogeneity, Robust Regression, Spatially Varying Coefficients Models

iForest 11 (5): 542-552 (2018) - doi: 10.3832/ifor2574-011
https://iforest.sisef.org/contents/?id=ifor2574-011

Research Articles: Auxin (IAA) and soluble carbohydrate seasonal dynamics monitored during xylogenesis and phloemogenesis in Scots pine

Fajstavr M, Paschová Z, Giagli K, Vavrčík H, Gryc V, Urban J — 2018-09-01

Fajstavr M, Paschová Z, Giagli K, Vavrčík H, Gryc V, Urban J

AUXIN (IAA) AND SOLUBLE CARBOHYDRATE SEASONAL DYNAMICS MONITORED DURING XYLOGENESIS AND PHLOEMOGENESIS IN SCOTS PINE

Abstract: The metabolic activity of phytohormones and the accumulation of carbohydrates affect the reactivation of the cambial zone and the radial increment of woody plants. We aimed to monitor the dynamics of indole-3-acetic acid (IAA) concentration and amounts of soluble carbohydrates during xylem and phloem formation of one growing season (2015). Six sample trees of Scots pine (Pinus sylvestris L.), aged 80 years on average, growing in the Sobešice research site (404 m a.s.l.) in the Czech Republic were selected. We obtained microcore samples at weekly intervals by the Trephor tool method for cell formation analysis and spectrophotometric determination of IAA and soluble carbohydrate contents. We found that time of the highest concentration of IAA (last week of April) coincided with time of the maximum number of cells in the cambial zone and highest expansion of the cell enlargement stage. When the IAA concentration was too low to be measured, latewood tracheids started to form, and late phloem sieve cell formation ceased. The highest concentration of soluble carbohydrates was 200.40 ± 21.6 µg GLU per sample (May 14). This coincided with the fastest weekly xylem cell increment. This research shows that IAA and soluble carbohydrate dynamics directly affects xylem and phloem formation.

Keywords: Pinus sylvestris L., Indole-3-Acetic Acid, Xylem, Phloem, Tracheids, Earlywood, Latewood

iForest 11 (5): 553-562 (2018) - doi: 10.3832/ifor2734-011
https://iforest.sisef.org/contents/?id=ifor2734-011

Research Articles: Assessing the performance of fire danger indexes in a Mediterranean area

Sirca C, Salis M, Arca B, Duce P, Spano D — 2018-09-01

Sirca C, Salis M, Arca B, Duce P, Spano D

ASSESSING THE PERFORMANCE OF FIRE DANGER INDEXES IN A MEDITERRANEAN AREA

Abstract: The fire danger (FD) defines the conditions less or more favourable for a fire ignition success and its propagation. FD indexes, that integrates environmental variables related to FD in more or less complex equations and systems, are widely used in wildfire prone countries for both scientific and operational purposes. Assessing the performance of FD indexes is challenging and this issue is quite debated within the fire community, which has been trying to apply several methodologies to evaluate FD indexes. The main aim of this work is to give a contribution to this effort. The analysis was conducted using data from a fire-prone Mediterranean area (Sardinia island, Italy), where 8 FD indexes were evaluated and compared using different statistical approaches. We calculated the daily FD values for the period 2000-2007 over the study area. A set of statistical tools (namely Spearman rank correlation, Index Value Distribution and Percentile Analysis, and Logistic Regression) were applied to evaluate the performance of each FD index by comparing FD values with fire occurrence indicators. The statistical tests revealed a large variability in FD indexes performance, depending also on fire activity conditions. Our results showed that two of the tested FD indexes reached a good overall performance. Findings from this study can help both the scientific community and local fire managers, supporting the evaluation of early warning systems and fire prevention strategies in the Mediterranean Basin.

Keywords: Fire Risk, Fire Danger Rating, Mediterranean Basin, Fire Occurrence, Wildfire

iForest 11 (5): 563-571 (2018) - doi: 10.3832/ifor2679-011
https://iforest.sisef.org/contents/?id=ifor2679-011

Research Articles: Plant phenotype affects oviposition behaviour of pine processionary moth and egg survival at the southern edge of its range

Hezil S, Chakali G, Battisti A — 2018-09-01

Hezil S, Chakali G, Battisti A

PLANT PHENOTYPE AFFECTS OVIPOSITION BEHAVIOUR OF PINE PROCESSIONARY MOTH AND EGG SURVIVAL AT THE SOUTHERN EDGE OF ITS RANGE

Abstract: Morphological traits of Aleppo pine (Pinus halepensis) needles in native and planted stands at the southern edge of its range influence oviposition behaviour of the pine processionary moth (Thaumetopoea pityocampa). Extreme environmental conditions result in a reduction in needle size of the host plant which corresponds to a lower rate of fecundity in the moth. Our results showed that egg batches were laid closer to the needle buds, especially on native trees with short needles, and this resulted in increased egg mortality. Number of eggs laid by the female moths did not vary between native and planted stands, nor did the number of parasitized eggs of the two common Hymenopteran parasitoids, Baryscapus servadeii and Ooencyrtus pityocampae. The observed differences in egg mortality are likely due to abiotic factors associated with the position of the egg batch on the needles. Thaumetopoea pityocampa eggs require a thermal niche for optimal development, and further measurements are required to determine the thermal threshold of these eggs. Understanding the role of climate in T. pityocampa populations will be an important factor for the survival of the Aleppo pine forests and protecting it from desertification.

Keywords: Algeria, Egg Parasitoid, Pinus halepensis, Plantation, Thaumetopoea pityocampa

iForest 11 (5): 572-576 (2018) - doi: 10.3832/ifor2675-011
https://iforest.sisef.org/contents/?id=ifor2675-011

Research Articles: Evergreen Quercus aquifolioides remobilizes more soluble carbon components but less N and P from leaves to shoots than deciduous Betula ermanii at the end-season

Cong Y, Wang A, He HS, Yu FH, Tognetti R, Cherubini P, Wang X, Li MH — 2018-08-01

Cong Y, Wang A, He HS, Yu FH, Tognetti R, Cherubini P, Wang X, Li MH

EVERGREEN QUERCUS AQUIFOLIOIDES REMOBILIZES MORE SOLUBLE CARBON COMPONENTS BUT LESS N AND P FROM LEAVES TO SHOOTS THAN DECIDUOUS BETULA ERMANII AT THE END-SEASON

Abstract: Remobilization is an important mechanism of resource conservation in plants. However, our understanding of whether the responses of resource remobilization to global warming differ between deciduous and evergreen trees remains unclear. We assessed resource remobilization from leaves to 1-year-old shoots in a deciduous (Betula ermanii) and an evergreen (Quercus aquifolioides) species along elevational gradients (i.e., temperature gradient) at the end of growing season. We aimed to test the hypotheses that the reallocation rate increased with increasing elevation and that more resources were reallocated from leaves to storage tissues in deciduous species than in evergreen species. We analyzed the concentrations of non-structural carbohydrates (NSC), nitrogen (N) and phosphorus (P), and compared the differences in remobilization efficiency of NSC, N, and P between leaves and shoots within each species and between the two species along the elevational gradients. Due to the different strategies of evergreen and deciduous species in nutrients use, the deciduous species had higher N and P remobilization rate, but lower remobilization rate of sugars, starch, and NSC than the evergreen species at the end of growing season. The remobilization rate of NSC, N, and P was significantly higher in trees at their upper limits compared to lower elevations. Our results suggest that trees reallocate resources from leaves to storage tissues before leaf senescence or at the end of growing season, to increase the resource use efficiency and to adapt to the harsh alpine environments. These results contribute to better understanding of the alpine treeline phenomenon in a changing world.

Keywords: Altitudinal Gradient, Non-structural Carbohydrates, Sugars, Starch, Nutrients, Reallocation

iForest 11 (4): 517-525 (2018) - doi: 10.3832/ifor2633-011
https://iforest.sisef.org/contents/?id=ifor2633-011

Technical Reports: Forest certification map of Europe

2018-08-01

Maesano M, Ottaviano M, Lidestav G, Lasserre B, Matteucci G, Scarascia Mugnozza G, Marchetti M

FOREST CERTIFICATION MAP OF EUROPE

Abstract: Forests cover nearly 40% of European land, with different country percentage and patchy distribution. The European forestry sector highlights that forest areas have different ownership: private (by firms, individual, or organizations) and public (State, communities or municipalities). The number of forestry holdings, size of landholding, and ownership types influence and drive forest management, governance and various other socio-economic linked issues. Moreover, forest owners determine management objectives and policies which influence the application of Sustainable Forest Management (SFM) practices. Several tools were developed to promote SFM, including forest certification. Numerous forest certification schemes are present across the world but the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC) are those prevalent. However, a map of certified forests is lacking, although mapping would be essential to locate the percentage of forest that are certified to be sustainably managed. The study mapped forest certification across 43 European states, according to 499 FSC and 284 PEFC reports and assessed the proportion of certified forest area on public and private land and the rate of increase. This research was carried out collecting information on European certified forest companies/owners and locating geographically their forests at sub-national level (regions, NUTS 2). The database of the Joint COST Action FACESMAP/UNECE/FAO was an important data source. At European level, about six percent of the forest is certified under FSC scheme, while about seven percent under PEFC scheme. As forest certification is a useful tool to manage forests aiming at the integration of economic, ecological and social sustainability, the knowledge of the location and area of certified forest in Europe could be important in motivating decision makers to increase these sustainably managed areas.

Keywords: Forest Policy, Sustainable Forest Management, Forest Certification, Forest Owners, Forest Management

iForest 11 (4): 526-533 (2018) - doi: 10.3832/ifor2668-011
https://iforest.sisef.org/contents/?id=ifor2668-011

Research Articles: Tree biomass and carbon density estimation in the tropical dry forest of Southern Western Ghats, India

2018-08-01

Padmakumar B, Sreekanth NP, Shanthiprabha V, Paul J, Sreedharan K, Augustine T, Jayasooryan KK, Rameshan M, Mohan M, Ramasamy EV, Thomas AP

TREE BIOMASS AND CARBON DENSITY ESTIMATION IN THE TROPICAL DRY FOREST OF SOUTHERN WESTERN GHATS, INDIA

Abstract: United Nations Framework Convention on Climate Change highlights the significance of carbon storage and emission in forests towards climate change mitigation. The aim of this study was to quantify the tree biomass and carbon density (carbon storage) in the tropical dry forest of the Chinnar Wildlife Sanctuary of Kerala located in the Southern Western Ghats, India. We investigated the species-wise contribution of carbon (C) storage, as well as the species-wise and plot-wise correlation between carbon and other dendrometric variables. We also analysed the girth (diameter) wise distribution of carbon and tree density in the study region. The study was conducted in eight selected sample plots of the region, each with an area of 0.1 hectare. Species-specific volume and specific gravity relationship coupled with suitable regression equation were used to estimate biomass. Tree carbon was assumed to be 47% of the biomass. The results showed that the average biomass and carbon density of the vegetation were 64.13 t ha-1 and 30.46 t-C ha-1, respectively. Among the 32 species identified, Tamarindus indica L. (17%), Hardwickia binata Roxb. (14%), Terminalia arjuna (Roxb. ex DC.) Wight & Arn (10%) and Pleiospermium alatum (Wight & Arn.) Swingle (10%) were dominant as for carbon storage. The correlation analysis showed that basal area is a good predictor of tree biomass and carbon, while the role of tree density and tree diversity remain uncertain in determining carbon storage. With respect to diametric class distribution, tree density showed a reverse J-shaped pattern indicating the sustainable regeneration of the analysed forest, where the small- (diameter at breast height 3-9 cm) to medium-sized trees (diameter at breast height 10-69 cm) were found to contribute to more than 50% of biomass and carbon in the forest. The study provides useful information for carbon mitigation strategies in a tropical dry forest in the Southern Western Ghats.

Keywords: Above Ground Tree Biomass, Carbon, Tropical Dry Forest, Kerala, Southern Western Ghats

iForest 11 (4): 534-541 (2018) - doi: 10.3832/ifor2190-011
https://iforest.sisef.org/contents/?id=ifor2190-011

Research Articles: Effect of imperfect detection on the estimation of niche overlap between two forest dormice

2018-07-18

Paniccia C, Di Febbraro M, Frate L, Sallustio L, Santopuoli G, Altea T, Posillico M, Marchetti M, Loy A

EFFECT OF IMPERFECT DETECTION ON THE ESTIMATION OF NICHE OVERLAP BETWEEN TWO FOREST DORMICE

Abstract: Quantification of niche overlap represents an important topic in several aspects of ecology and conservation biology, although it could be potentially affected by imperfect detection, i.e., failure to detect a species at occupied sites. We investigate the effect of imperfect detection on niche overlap quantification in two arboreal rodents, the edible dormouse (Glis glis) and the hazel dormouse (Muscardinus avellanarius). For both species, we used Generalized Linear Mixed Models (GLMM) to estimate the occurrence probability and Occupancy Models (OM) to calculate occurrence and detection probabilities. By comparing these predictions through niche equivalency and similarity tests, we first hypothesised that methods correcting for imperfect detection (OM) provide a more reliable estimate of niche overlap than traditional presence/ absence methods (GLMM). Furthermore, we hypothesised that GLMM mainly estimate species detectability rather than actual occurrence, and that a low number of sampling replicates provokes an underestimation of species niche by GLMM. Our results highlighted that GLMM-based niche overlap yielded significant outcomes only for the equivalency test, while OM-based niche overlap reported significant outcomes for both niche equivalency and similarity tests. Moreover, GLMM occurrence probabilities and OM detectabilities were not statistically different. Lastly, GLMM predictions based on single sampling replicates were statistically different from the average occurrence probability predicted by GLMM over all replicates. We emphasized how accounting for imperfect detection can improve the statistical significance and interpretability of niche overlap estimates based on occurrence data. Under a habitat management perspective, an accurate quantification of niche overlap may provide useful information to assess the effects of different management practices on species occurrence.

Keywords: Occupancy Models, Generalized Linear Mixed Models, Forest Management, Niche Overlap

iForest 11 (4): 482-490 (2018) - doi: 10.3832/ifor2738-011
https://iforest.sisef.org/contents/?id=ifor2738-011

Research Articles: The concept of green infrastructure and urban landscape planning: a challenge for urban forestry planning in Belgrade, Serbia

Vasiljević N, Radić B, Gavrilović S, Šljukić B, Medarević M, Ristić R — 2018-07-18

Vasiljević N, Radić B, Gavrilović S, Šljukić B, Medarević M, Ristić R

THE CONCEPT OF GREEN INFRASTRUCTURE AND URBAN LANDSCAPE PLANNING: A CHALLENGE FOR URBAN FORESTRY PLANNING IN BELGRADE, SERBIA

Abstract: The beginning of the 21st century has witnessed a growth in our understanding of the importance of planning urban landscapes in the context of urban population growth and unpredictable climatic conditions. In the search for responses to the challenges set by the development of contemporary urban landscapes, researchers have offered solutions based on the concept of sustainable and resilient cities, whose spatial development would be based on an interdisciplinary approach to strategy development: biodiversity, urban ecological networks and connectivity, multifunctionality and modularity. Although the concepts of a green infrastructure, in their spatial and functional dimensions, allow the application of such strategies, there are still problems when it comes to implementation and measuring the results achieved. At the same time, there is a growing discussion of the important role played by urban forestry in the context of the collaborative planning of urban landscapes and the application of the ideas of a green infrastructure. The key question is: what are the modalities of application of the concept of green infrastructure in the process of planning the development of the modern city and how can the resulting benefits be evaluated? With the modalities of application of the concept of green infrastructure in mind, we discuss its multi-scale and multifunctional dimensions as applied in the case of Serbia. The realisation of the green infrastructure concept is presented through the example of the Urban Forest Management Plan for the City of Belgrade - Mladenovac Municipality. The results of using the spatial-ecological approach in creating the plan and establishing connectivity as a new aim in forest management planning show that the implementation of the green infrastructure concept, and the achieved multifunctional ecosystem values, can be presented on the basis of the parameters of landscape metrics. In light of the new urban world, future research should focus on the application of the landscape ecological approach of the green infrastructure concept in collaborative planning at the urban landscape scale, which allows the creation of ecosystem services and benefits to human well-being.

Keywords: Green Infrastructure (GI), Urban Landscape Planning, Urban Forestry, Ecosystem Services, Biodiversity, Recreation, Connectivity

iForest 11 (4): 491-498 (2018) - doi: 10.3832/ifor2683-011
https://iforest.sisef.org/contents/?id=ifor2683-011

Research Articles: Real-Time PCR for Ceratocystis platani detection: in-depth validation to assess the diagnostic potential and include additional technical options

2018-07-18

Lumia V, Modesti V, Brunetti A, Wilkinson CL, Di Lernia G, Harrington TC, Pilotti M

REAL-TIME PCR FOR CERATOCYSTIS PLATANI DETECTION: IN-DEPTH VALIDATION TO ASSESS THE DIAGNOSTIC POTENTIAL AND INCLUDE ADDITIONAL TECHNICAL OPTIONS

Abstract: A high-performing detection method is essential to safeguard those countries that are still unaffected by canker stain, a devastating disease of Platanus spp. caused by Ceratocystis platani. We previously developed EvaGreen and Taqman-based Real-Time PCR to detect this pathogen, but in-depth validation is needed to guarantee users about its effectiveness and promote its utilization. In this work we present a validation study designed according to EPPO standards, focusing on the analytical and diagnostic sensitivity and specificity. We extend its technical application using SYBR Green. By performing standard curves and eight-replication-based experiments, we established the detection limit at 3 fg C. platani gDNA per PCR reaction. The repeatability and the operator-based reproducibility of the Real-Time PCR was demonstrated. Different gDNA extraction events by different operators and different gDNA extraction modalities did not affect the detection limit. The detection limit threshold cycle was earliest with SYBR Green, followed by Taqman, and EvaGreen. Spiking 6 µl DNA extractions of uninfected, necrotized wood with 3 fg C. platani gDNA confirmed the detection limit: 3 fg C. platani gDNA per PCR reaction, i.e., 0.5 fg gDNA per µl of wood extract. The assays tolerated 6 µl of necrotic C. platani-infected wood extracts without inhibition except for long-dead wood samples, while the 2 µl dose consistently allowed for successful detection. Detection of the pathogen in infected samples showed the highest diagnostic sensitivity with the SYBR Green assay. Agarose gel electrophoresis and staining was validated for visualizing amplicons, even at the detection limit. The specificity of the method was tested against 23 isolates representing the diversity of Ceratocystidaceae, and most species were not detected at 5 ng gDNA. However, some South American strains of the C. fimbriata complex were detected at doses as low as 5 fg. The method remains specific for C. platani detection as no other Ceratocystidaceae are known to colonize plane tree and the species within the geographic range of canker stain of plane tree were only detected at 500 pg or more gDNA. This work paves the way for a performance study of inter-laboratory comparisons.

Keywords: Canker Stain, Real-Time PCR, Validation, EvaGreen, Taqman, SYBR Green

iForest 11 (4): 499-509 (2018) - doi: 10.3832/ifor2527-011
https://iforest.sisef.org/contents/?id=ifor2527-011

Research Articles: Comparison of genetic parameters between optimal and marginal populations of oriental sweet gum on adaptive traits

Alan M — 2018-07-18

Alan M

COMPARISON OF GENETIC PARAMETERS BETWEEN OPTIMAL AND MARGINAL POPULATIONS OF ORIENTAL SWEET GUM ON ADAPTIVE TRAITS

Abstract: Genetic parameters of 9 oriental sweetgum (Liquidambar orientalis Mill.) populations were estimated at a common garden test. Open-pollinated seeds were collected from 16-27 families for each population. The common garden test was established in 2009 using a randomized complete block design in 25 blocks with single tree plot, with each block included 223 families. Breast height diameter, height and crown diameter were measured at the age of five. The purpose of study was to compare the genetic parameters of optimal and marginal populations and to assess the findings for genetic conservation. The study revealed significant variability in all traits evaluated. In variance components, variation among populations was three times higher than that of families. Individual heritability estimates for breast height diameter, height and crown diameter pooled across the whole dataset (marginal and optimal populations) were 0.21 ± 0.04, 0.27 ± 0.04 and 0.11 ± 0.03 and additive genetic coefficients of variation were 13.4%, 9.1% and 7.1%, respectively. Individual heritability estimates for breast height diameter, height and crown diameter in marginal and optimal populations were 0.27 ± 0.10, 0.19 ± 0.08 and 019 ± 0.08 and 0.19 ± 0.04, 0.29 ± 0.05 and 0.09 ± 0.03, respectively. Additive genetic coefficients of variation for breast height diameter, height and crown diameter were 16.7%, 8.3% and 10.8% in marginal and 12.8%, 9.1% and 6.2% in optimal populations, respectively. While breast height diameter and crown diameter were more heritable for marginal populations, height was more heritable for optimal populations. These findings are discussed in terms of genetic conservation of oriental sweet gum.

Keywords: Liquidambar orientalis, Genetic Variation, Individual Heritability, Gene Conservation, Climate Change

iForest 11 (4): 510-516 (2018) - doi: 10.3832/ifor2450-011
https://iforest.sisef.org/contents/?id=ifor2450-011

Research Articles: Weak isolation by distance and geographic diversity gradients persist in Scottish relict pine forest

González-Díaz P, Cavers S, Iason GR, Booth A, Russell J, Jump AS — 2018-07-02

González-Díaz P, Cavers S, Iason GR, Booth A, Russell J, Jump AS

WEAK ISOLATION BY DISTANCE AND GEOGRAPHIC DIVERSITY GRADIENTS PERSIST IN SCOTTISH RELICT PINE FOREST

Abstract: Gene flow is one of the main factors shaping genetic diversity within and among tree populations, and occurs through pollen and seed dispersal. Recent findings of pollen-release asynchronies in distant populations of Scots pine (Pinus sylvestris L.) within Scotland suggest that gene dispersal among more distant populations might be less effective than previously thought. Limited gene dispersal is one of the major factors causing genetic structure for neutral markers, and pollen-release asynchrony could have driven isolation by distance (IBD) among Scottish populations. Previous studies of neutral markers found little differentiation among Scottish populations of Scots pine, however they did not consider IBD over the full Scottish range. We analysed data from 6 nuclear simple sequence repeats (SSR) and 5 chloroplast SSR loci in a total of 540 individuals of Scots pine from 18 populations across Scotland. Our aim was to assess contemporary levels and distribution of genetic variation and to test if the distribution of genetic diversity was consistent with IBD. We also analysed patterns of gene flow that could have contributed to the observed patterns of variation. Levels of genetic diversity were high, for both nuclear and chloroplast markers within populations, and there was no significant differentiation among populations. A weak signal of IBD was present. We found an increase in nuclear diversity towards the East along with greater gene flow in a West-East direction commensurate with the prevailing winds. Our findings suggest that this wind-driven gene flow is dominant over genetic drift and prevents differentiation among the Scottish populations. It may also counteract any pollen-release asynchronies among populations.

Keywords: Pinus sylvestris, Genetic Diversity, Gene Flow, Isolation by Distance, Prevailing Winds

iForest 11 (4): 449-458 (2018) - doi: 10.3832/ifor2454-011
https://iforest.sisef.org/contents/?id=ifor2454-011

Research Articles: Assessing the availability of forest biomass for bioenergy by publicly available satellite imagery

Vacchiano G, Berretti R, Motta R, Mondino Borgogno E — 2018-07-02

Vacchiano G, Berretti R, Motta R, Mondino Borgogno E

ASSESSING THE AVAILABILITY OF FOREST BIOMASS FOR BIOENERGY BY PUBLICLY AVAILABLE SATELLITE IMAGERY

Abstract: Forest biomass is a renewable energy source, more climate-friendly than fossil fuels and widely available in Europe. The wood energy chain has been suggested as a means to re-activate forest management and improve the value of forest stands in marginalized rural areas. However, wall-to-wall estimates of forest biomass, needed to design the location and size of power and heat biomass plants in any given territory, are notoriously difficult to obtain. This paper tests an algorithm to predict forest biomass using publicly available Landsat satellite imagery in the Liguria region, northern Italy. We used regional forest inventory data to train and validate an artificial neural network (ANN) classifier that uses remotely-sensed information such as three principal components of Landsat-5 TM spectral bands, the Enhanced Vegetation Index (EVI), and topography, to retrieve aboveground live tree volume. Percent root mean square error was -9% and -23% for conifers and broadleaves respectively in the calibration dataset, and -27% and -24% in the validation dataset. The reconstructed volume map was updated to present day using current volume increment rates reported by the Italian National Forest Inventory. A wall-to-wall map of forest biomass from harvest residues was finally produced based on species-specific wood density, biomass expansion factors, volume logged for timber assortments, forest accessibility, and topography. Predicted aboveground forest volume ranged from 81 to 391 m3 ha-1. In forests available for wood supply (70% of the total), planned volume removals averaged 25.4 m3 ha-1, or 18.7% of the average standing stock across. Biomass available for bioenergy supply was 1.295.921 million Mg dry matter or 8.95 Mg ha-1. This analysis workflow can be replicated in all mountain regions with a predominant broadleaved coppice component.

Keywords: Artificial Neural Networks, Mixed Forests, Landsat, Mediterranean Mountains, Vegetation Indices, Wood Energy Chain

iForest 11 (4): 459-468 (2018) - doi: 10.3832/ifor2655-011
https://iforest.sisef.org/contents/?id=ifor2655-011

Research Articles: Growing season water balance of an inner alpine Scots pine (Pinus sylvestris L.) forest

Wieser G, Gruber A, Oberhuber W — 2018-07-02

Wieser G, Gruber A, Oberhuber W

GROWING SEASON WATER BALANCE OF AN INNER ALPINE SCOTS PINE (PINUS SYLVESTRIS L.) FOREST

Abstract: We estimated components of the water cycle of a 150-year-old Pinus sylvestris forest in an inner Alpine dry valley of the Tyrol, Austria throughout five growing seasons. Forest canopy transpiration (TC) was measured by sap flow measurements scaled to the stand canopy level. Estimates of understory transpiration and forest floor evaporation (ETU) were derived from the soil water budget method, while interception (I) was modelled. Growing season cumulative evapotranspiration (ET = TC + ETU + I) varied between 256 and 322 mm or 51 to 79% of the growing season precipitation. The contribution of TC, ETU, and I to ET were 33, 40 and 27% respectively. Although these values of each layer (evapo)-transpiration are in good agreement with studies carried out in other European Scots pine forests, our estimated growing season total forest water use (Ttot = Tc + ETu) of 200-244 mm is at the lower end of values reported for coniferous forest ecosystems, and thus reflects an adaptation to the low shallow soil water availability. We conclude that Scots pine forests in inner alpine dry valleys are able to cope with high evaporative demand, even when shallow soil water availability is limited.

Keywords: Forest Water Balance, Scots Pine, Dry Inner Alpine Valley, Evapotranspiration, Interception, Runoff

iForest 11 (4): 469-475 (2018) - doi: 10.3832/ifor2626-011
https://iforest.sisef.org/contents/?id=ifor2626-011

Research Articles: Long-term effects of stem girdling on needle structure in Scots pine

Gebauer R, Plichta R, Foit J, Cermák V, Urban J — 2018-07-02

Gebauer R, Plichta R, Foit J, Cermák V, Urban J

LONG-TERM EFFECTS OF STEM GIRDLING ON NEEDLE STRUCTURE IN SCOTS PINE

Abstract: Stem girdling is the process of completely removing a strip of cork and phloem tissue. Phloem is the living tissue which serves as the main long-distance pathway for transporting carbohydrates produced during photosynthesis to all parts of the plant where needed, from source leaves to sinks. Stem girdling has been used to study several functional aspects of phloem and their direct impacts on tree growth. Although both photosynthesis and transpiration processes take place in needles, no studies exist which investigate the effect of source-sink disturbance on needle structure. In this study, we evaluated changes in needle morphology and anatomy in current-year Scots pine needles 227 and 411 days after girdling (DAG). Although the studied needle parameters recorded 227 DAG were from 2 to 20% higher than the same parameters in control needles, the differences were not significant. On the other hand, needles 411 DAG were thinner, with decreased cross-sectional areas, phloem areas, vascular cylinder areas, needle dry mass, needle density, and needle flatness when compared to control needles. Marked variations in needle growth were observed 411 DAG, with a smaller number of correlations among almost all studied needle parameters in needles 411 DAG when compared to control needles or needles 227 DAG. Structural development determining needle flatness, needle density, and leaf mass per area (LMA) appeared to have driving factors that were independent of the other studied needle parameters, as correlations with other parameters were not significant in any treatment. The changes in overall needle structure observed after long-term stem girdling provide new insights into the processes that occur as a result of source-sink disturbances. This type of data could be helpful, for example, in studies specifically focused on phloem transport, tree carbon relationships, or investigations modeling gas exchange. Our study might also support gene expression studies, which could provide further knowledge about the regulatory mechanisms that determine needle size and structural form.

Keywords: Anatomy, Cross-section, Morphology, Pinus sylvestris, Phloem, Source-Sink Disturbance

iForest 11 (4): 476-481 (2018) - doi: 10.3832/ifor2648-011
https://iforest.sisef.org/contents/?id=ifor2648-011

Review Papers: Linking deadwood traits with saproxylic invertebrates and fungi in European forests - a review

Parisi F, Pioli S, Lombardi F, Fravolini G, Marchetti M, Tognetti R — 2018-06-18

Parisi F, Pioli S, Lombardi F, Fravolini G, Marchetti M, Tognetti R

LINKING DEADWOOD TRAITS WITH SAPROXYLIC INVERTEBRATES AND FUNGI IN EUROPEAN FORESTS - A REVIEW

Abstract: Deadwood is a substantial component of forests playing a central role in many ecosystem processes. It provides habitats for a multitude of wood-dependent organisms, maintaining the ecosystem health and reducing the effect of natural disturbances. Deadwood is recognized as an indicator of local species diversity and contributes to the global carbon pools and nutrient cycles. Despite its importance, how saproxylic communities respond to deadwood dynamics across multiple spatial and temporal scales is still not clear. With the present review, we aim to summarize the effects of deadwood characteristics on the diversity and composition of saproxylic insects and fungi, with focus on European forests. We also discuss the influence of other biotic and abiotic components that indirectly affect these communities by altering wood continuity and variety. Niche differentiation is the main ecological driver of saproxylic organisms, as the presence of multiple microhabitats supports differently specialized taxa. The assemblage and richness of these saproxylic communities within forest ecosystems can be considered as indicators of climate-smart forestry trajectories. This aspect deserves to be regarded as a major target in sustainable forest management plans, especially in mountain areas, where the conservation of threatened species and the promotion of biodiverse forests are considered a priority.

Keywords: Deadwood Accumulation, Deadwood Decomposition, Saproxylic Insects, Saproxylic Fungi, European Forests, Conservation-oriented Forestry

iForest 11 (3): 423-436 (2018) - doi: 10.3832/ifor2670-011
https://iforest.sisef.org/contents/?id=ifor2670-011

Short Communications: Respiratory costs of woody tissues in a Quercus pyrenaica coppice

Salomón RL, Rodríguez-Calcerrada J, Gil L, Valbuena-Carabaña M — 2018-06-18

Salomón RL, Rodríguez-Calcerrada J, Gil L, Valbuena-Carabaña M

RESPIRATORY COSTS OF WOODY TISSUES IN A QUERCUS PYRENAICA COPPICE

Abstract: Long-term coppicing leads to the development of massive root systems. A disproportionate carbon investment in root maintenance has been pointed as a cause of the widespread decline of abandoned coppices. We aimed at assessing how coppicing has influenced root and shoot development and related carbon loss ascribed to maintenance of woody tissues in Quercus pyrenaica. For this goal, results from published studies on root dynamics, woody biomass and respired CO2 fluxes in an abandoned Q. pyrenaica coppice were integrated and extended to quantify overall respiratory expenditures of above- and below-ground woody organs. Internal and external CO2 fluxes together with soil CO2 efflux were monitored in eight stems from one clone across a growing season. Stems and roots were later harvested to quantify the functional biomass and scale up root and stem respiration (RR and RS, respectively) to the clone and stand levels. Below- and above-ground biomass was roughly equal. However, the root-to-shoot ratio of respiration (RR/RS) was generally below one. Relatively higher RS suggests enhanced metabolic activity aboveground during the growing season, and highlights an unexpected but substantial contribution of RS to respiratory carbon losses. Moreover, soil and stem CO2 efflux to the atmosphere in Q. pyrenaica fell in the upper range of reported rates for various forest stands distributed worldwide. We conclude that both RS and RR represent an important carbon sink in this Q. pyrenaica abandoned coppice. Comparatively high energetic costs in maintaining multiple stems per tree and centennial root systems might constrain aboveground performance and contribute to coppice stagnation.

Keywords: Carbon Loss, CO2 Fluxes, Coppice Stagnation, Oak, Resprouting Species, Root Respiration, Stem Respiration

iForest 11 (3): 437-441 (2018) - doi: 10.3832/ifor2599-011
https://iforest.sisef.org/contents/?id=ifor2599-011

Research Articles: Preliminary results of the tolerance to inorganic contaminants and phytoextraction potential of twelve ornamental shrub species tested on an experimental contaminated site

Vincent G, Shang K, Zhang G, Labrecque M — 2018-06-18

Vincent G, Shang K, Zhang G, Labrecque M

PRELIMINARY RESULTS OF THE TOLERANCE TO INORGANIC CONTAMINANTS AND PHYTOEXTRACTION POTENTIAL OF TWELVE ORNAMENTAL SHRUB SPECIES TESTED ON AN EXPERIMENTAL CONTAMINATED SITE

Abstract: In urban areas of China, several plant species are commonly used for ornamental purposes. Many of these plants have demonstrated a good capacity to resist these varied urban stresses, and it would be relevant to verify whether they can be grown on polluted sites and demonstrate some phytoremediation potential. Twelve ornamental shrub species were chosen to be tested for tolerance to inorganic contaminants and capacity to absorb and concentrate heavy metals in their aerial parts. A large split-plot trial comprising 20 plots was set up, and soil was spiked with different metals (Cu, Pb and Zn). In general, all twelve shrub species performed well regardless of the treatment. Two Hibiscus species, H. mutabilis and H. syriacus “Hamabo” were particularly productive. In terms of capacity to uptake metals, two of the best performing species were Spiraea japonica, for copper, and Nandina domestica, for lead. Bioconcentration and transfer factors were low. This could be related to weak development of the root systems in these recently established plants. Species with high yield, such as the two Hibiscus species, presented more interesting values in terms of quantity of metal extracted, and could eventually be recommended for decontamination of soils polluted by inorganics.

Keywords: Phytoremediation, Phytoectraction, Trace Elements, Ornamental Shrub Species, Urban Stresses

iForest 11 (3): 442-448 (2018) - doi: 10.3832/ifor2716-011
https://iforest.sisef.org/contents/?id=ifor2716-011

Research Articles: Nutrient uptake, allocation and biochemical changes in two Chinese fir cuttings under heterogeneous phosphorus supply

Farooq TH, Tigabu M, Ma X, Zou X, Liu A, Odén PC, Wu P — 2018-06-05

Farooq TH, Tigabu M, Ma X, Zou X, Liu A, Odén PC, Wu P

NUTRIENT UPTAKE, ALLOCATION AND BIOCHEMICAL CHANGES IN TWO CHINESE FIR CUTTINGS UNDER HETEROGENEOUS PHOSPHORUS SUPPLY

Abstract: Plant-available nutrients in soils are usually distributed in a heterogeneous or patchy manner. Plant responses to low levels of phosphorous (P) are not uniform across and within species. In this study, we examined the adaptive role of physiological plasticity (increased rate of nutrient uptake in localized zones) to the heterogeneous distribution of P in the soil, and whether low P stress transcends to the shoot and triggers similar biochemical changes that enhance tolerance. Two Chinese fir clones with high P efficiency (M1, which is tolerant to low P, and M4 which is able to decouple fixed P) were chosen as the research materials and their physiological responses to low P stress were examined using a sand culture experiment. For both clones, there was no significant difference in nutrient concentration between P-replete and P-deficient patches. Heterogeneous P supply did not affect the allocation of nutrients to the above-ground parts of the plants. The activity of acid phosphatase (APase) and malondialdehyde (MDA) content increased initially but declined with increasing duration of stress, while the content of soluble protein and total chlorophyll contents remained unaffected by the heterogeneous P supply. We conclude that physiological plasticity plays no role in adaptation to low P stress in these clones, while the changes in APase activity and MDA content in needles suggest functional metabolic processes are involved in enhancing P-efficiency in these clones.

Keywords: Chinese Fir, Physiological Plasticity, Low Phosphorus Stress, Acid Phosphatase Activity, Nutrient Accumulation

iForest 11 (3): 411-417 (2018) - doi: 10.3832/ifor2657-011
https://iforest.sisef.org/contents/?id=ifor2657-011

Review Papers: Moisture in modified wood and its relevance for fungal decay

Thybring EE, Kymäläinen M, Rautkari L — 2018-06-05

Thybring EE, Kymäläinen M, Rautkari L

MOISTURE IN MODIFIED WOOD AND ITS RELEVANCE FOR FUNGAL DECAY

Abstract: Water plays an essential role in fungal decay of wood, and limiting the cell wall moisture content by chemical modification can effectively improve the durability of the material. Investigating the wood-water relations of modified material under climatic conditions relevant for fungal decay are, however, experimentally challenging. Most studies in literature therefore focus on moisture sorption under conditions outside those of importance for fungal decay. This review discusses the validity of such data for characterising the wood-water relations at very humid climatic conditions, relevant for fungal decay. Moreover, the review attempts to cover the basics of fungal decay, the important role of water, and how controlling water content by modification can improve durability.

Keywords: Modification, Wood, Moisture, Experimental Techniques

iForest 11 (3): 418-422 (2018) - doi: 10.3832/ifor2406-011
https://iforest.sisef.org/contents/?id=ifor2406-011

Research Articles: Response of juvenile progeny of seven forest tree species and their populations to simulated climate change-related stressors, heat, elevated humidity and drought

Pliura A, Jankauskiene J, Lygis V, Suchockas V, Bajerkevičiene G, Verbylaite R — 2018-05-15

Pliura A, Jankauskiene J, Lygis V, Suchockas V, Bajerkevičiene G, Verbylaite R

RESPONSE OF JUVENILE PROGENY OF SEVEN FOREST TREE SPECIES AND THEIR POPULATIONS TO SIMULATED CLIMATE CHANGE-RELATED STRESSORS, HEAT, ELEVATED HUMIDITY AND DROUGHT

Abstract: The study aimed to evaluate response and phenotypic plasticity of juvenile progeny of seven forest tree species Pinus sylvestris, Picea abies, Quercus robur, Fraxinus excelsior, Alnus glutinosa, Betula pendula and Populus tremula and their populations to climate change-related stressors, simulated in a phytotron - heat and elevated humidity and heat and drought - in comparison to performance in ambient (control) conditions. Treatment effect on sapling morphometric, physiological and biochemical traits was significant except for health condition, transpiration and photosynthetic rates and water use efficiency (WUE). Species effect and species-by-treatment interaction were strongly significant in most traits studied, indicating a great inter-specific variability of responses to the applied treatments. Compared to control, stem diameter increment was lower for most species following both hot-wet and hot-dry treatments, while treatment impact on height increment was less pronounced and sometimes even positive. Drought caused significant defoliation in P. tremula, A. glutinosa and B. pendula, while under hot-wet treatment the defoliation in most species was lower than in control. Following hot dry treatment, WUE in P. abies, P. sylvestris and B. pendula was lower than following both hot-wet treatment and control, while in P. tremula, A. glutinosa and Q. robur WUE was higher. This suggests that the latter species are able to maintain a balance between photosynthesis and transpiration. Photosynthetic rate was highest in P. tremula, B. pendula and A. glutinosa, however it was much more negatively affected by water deficit in these three species than in other tested species. In most cases, drought had a negative effect on production of pigments in deciduous tree species, which, together with increased amounts of malondialdehyde and hydrogen peroxide, indicated a presence of an oxidative stress. Significant population effect and population-by-treatment interactions found for most traits showed different plasticity and response of tree populations to the treatments. Although, only 19% of the populations showed significant ecovalencies. Some of the observed reactions may not be considered as adaptive acclimation as decreasing growth of some species and populations indicates deteriorating performance which may lead to changes in their competitiveness, thus compromising regeneration, persistence of natural successions and sustainability of forest ecosystems.

Keywords: Climate Change, Stress, Growth, Physiology, Transpiration, Photosynthesis, Water Use Efficiency, Biochemical Parameters, Phenotypic Plasticity

iForest 11 (3): 374-388 (2018) - doi: 10.3832/ifor2340-011
https://iforest.sisef.org/contents/?id=ifor2340-011

Research Articles: COSMO-SkyMed potential to detect and monitor Mediterranean maquis fires and regrowth: a pilot study in Capo Figari, Sardinia, Italy

Vaglio Laurin G, Avezzano R, Bacciu V, Frate FD, Papale D, Virelli M — 2018-05-15

Vaglio Laurin G, Avezzano R, Bacciu V, Frate FD, Papale D, Virelli M

COSMO-SKYMED POTENTIAL TO DETECT AND MONITOR MEDITERRANEAN MAQUIS FIRES AND REGROWTH: A PILOT STUDY IN CAPO FIGARI, SARDINIA, ITALY

Abstract: Mediterranean maquis is a complex and widespread ecosystem in the region, intrinsically prone to fire. Many species have developed specific adaptation traits to cope with fire, ensuring resistance and resilience. Due to the recent changes in socio-economy and land uses, fires are more and more frequent in the urban-rural fringe and in the coastlines, both now densely populated. The detection of fires and the monitoring of vegetation regrowth is thus of primary interest for local management and for understanding the ecosystem dynamics and processes, also in the light of the recurrent droughts induced by climate change. Among the main objectives of the COSMO-SkyMed radar constellation mission there is the monitoring of environmental hazards; the very high revisiting time of this mission is optimal for post-hazard response activities. However, very few studies exploited such data for fire and vegetation monitoring. In this research, Cosmo-SkyMed is used in a Mediterranean protected area covered by maquis to detect the burnt area extension and to conduct a mid-term assessment of vegetation regrowth. The positive results obtained in this research highlight the importance of the very high-resolution continuous acquisitions and the multi-polarization information provided by COSMO-SkyMed for monitoring fire impacts on vegetation.

Keywords: Cosmo-SkyMed, Maquis, Fire, Mediterranean Vegetation

iForest 11 (3): 389-395 (2018) - doi: 10.3832/ifor2623-011
https://iforest.sisef.org/contents/?id=ifor2623-011

Research Articles: Climate change may threaten the southernmost Pinus nigra subsp. salzmannii (Dunal) Franco populations: an ensemble niche-based approach

2018-05-15

Navarro-Cerrillo RM, Duque-Lazo J, Manzanedo RD, Sánchez-Salguero R, Palacios-Rodriguez G

CLIMATE CHANGE MAY THREATEN THE SOUTHERNMOST PINUS NIGRA SUBSP. SALZMANNII (DUNAL) FRANCO POPULATIONS: AN ENSEMBLE NICHE-BASED APPROACH

Abstract: We used Species Distribution Modeling to predict the probability of Iberian pine (Pinus nigra subsp. salzmannii [Dunal] Franco) occurrences in southern Spain in response to environmental variables and to forecast the effects of climate change on their predicted geographical distribution. The ensemble modeling approach “biomod2” was used, together with present Iberian pine data, to predict the current potential distribution based on bioclimatic explanatory variables (200 m resolution) and to forecast future suitability by studying three periods (2040, 2070, and 2100), considering the Global Circulation Models BCM2, CNCM3, and ECHAM5, and the regional model EGMAM, for different scenarios (SRAB1, SRA2, SRB1). Model evaluation was performed using Kappa, True Skills Statistic (TSS), and Area Under the Curve (AUC) values. The biomod2 approach highlighted the average number of days with a minimum temperature equal to or below 0°C, annual precipitation, and aridity index as the most important variables to describe the P. nigra occurrence probability. Model performances were generally satisfactory and the highest AUC values and high stability of the results were given by GAM and GLM, but MaxEnt and the SRE model were scarcely accurate according to all our statistics. The ensemble Species Distribution Modeling of P. nigra in Andalusia predicted the highest probability of species occurrence in the eastern areas, Sierra de Cazorla being the area with the highest occurrence of P. nigra in Andalusia. In the future habitat, the general probability of P. nigra occurrence in Andalusia will decrease widely; the species is expected to lose habitat suitability at moderate altitudes and its occurrence probability will have decreased by nearly 70% on average by 2100, affected by the selected scenario. Populations in Sierra de Cazorla are those most suitable for P. nigra growth, even under the most pessimistic scenarios. It is likely that the natural southern populations of P. nigra will be very sensitive to changes in climate.

Keywords: Species Distribution Modeling, Climate Change, Ensemble Modeling, Iberian Pine, Mediterranean Relict Forests

iForest 11 (3): 396-405 (2018) - doi: 10.3832/ifor2588-011
https://iforest.sisef.org/contents/?id=ifor2588-011

Technical Notes: Effect of tree age on chemical compounds of ancient Anatolian black pine (Pinus nigra subsp. pallasiana) needles in Northwest Turkey

Turfan N, Alay M, Sariyildiz T — 2018-05-15

Turfan N, Alay M, Sariyildiz T

EFFECT OF TREE AGE ON CHEMICAL COMPOUNDS OF ANCIENT ANATOLIAN BLACK PINE (PINUS NIGRA SUBSP. PALLASIANA) NEEDLES IN NORTHWEST TURKEY

Abstract: Plant primary and secondary metabolites are chemical compounds synthesized for essential functions, such as growth and development (primary metabolites), and specific functions, such as pollinator attraction or defense against herbivory (secondary metabolites). Their concentrations in plants are genetically determined, but are also affected by environmental factors. Among these factors, plant age has been reported to influence plant chemical compounds under similar environmental conditions. We aimed to investigate the chemical compounds of ancient Anatolian black pine (Pinus nigra subsp. pallasiana) needles from trees of different ages. Needles of over 500-, 200-, 100-, 50-, and 25-year-old black pine trees growing under similar environmental conditions were sampled and analyzed for photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), proline, total soluble protein, glucose, sucrose, total soluble sugar, peroxidation level (MDA-malondialdehyde), hydrogen peroxide (H2O2) and antioxidants such as ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) activities. Significant differences for chemical composition associated with age were found. In general, results showed that over 500-year-old Anatolian black pine had the highest proline, total soluble protein, H2O2, sucrose, total soluble carbohydrates, APX, CAT and SOD concentrations, whereas they had the lowest chlorophyll a, total chlorophyll, total carotenoid and glucose concentrations. However, 200-year-old trees had the highest glucose, but the lowest chlorophyll b, proline, H2O2 and total soluble carbohydrates. 50- and 25-year-old trees together showed the highest chlorophyll a and b, total chlorophyll, total carotenoid and MDA, but lowest total soluble protein and sucrose. In conclusion, these results provide valuable insight into the chemical composition of Anatolian black pine needles in relation to their age, and can be used for complementing studies on tree growth-defence relationships.

Keywords: Ancient Trees, Anatolian Black Pine, Chemical Composition, Turkey

iForest 11 (3): 406-410 (2018) - doi: 10.3832/ifor2665-011
https://iforest.sisef.org/contents/?id=ifor2665-011

Research Articles: Recovery of above-ground tree biomass after moderate selective logging in a central Amazonian forest

2018-05-04

Otani T, Lima AJ, Suwa R, Amaral MR, Ohashi S, Pinto AC, Dos Santos J, Kajimoto T, Higuchi N, Ishizuka M

RECOVERY OF ABOVE-GROUND TREE BIOMASS AFTER MODERATE SELECTIVE LOGGING IN A CENTRAL AMAZONIAN FOREST

Abstract: We examined the recovery and dynamics of living tree above-ground biomass (AGB) after selective logging in an Amazonian terra firme forest managed by a private company. The forest consisted of 24 blocks (including one set aside for conservation) selectively logged in different years on a managed schedule. Trees ≥10 cm in diameter at breast height (dbh) were surveyed in 2006 in 192 0.25-ha plots, in 2010 in 119 plots, and in 2012-2013 in 54 plots. A logistic growth model factoring in logging dynamics and mean AGB of a block in these years was established. Referencing the mean AGB of the unlogged forest, the model indicated that the logged forest would take on average 14 years to regain its preharvest AGB after selective logging at 1.9 trees ha-1 (dbh > 50 cm). In 2010 and 2012-2013, the AGB increased significantly for small and large trees (10-20 cm and >60 cm dbh, respectively) in the logged forest. In contrast, it decreased significantly for medium-sized trees (30-50 cm dbh) in the unlogged forest. Comparisons with the previous studies mainly conducted in the other regions of Amazon suggested that the estimated AGB recovery period with moderate logging intensity was almost appropriate and likely acceptable to forest managers.

Keywords: Annual Increment, Dynamics, Logistic Growth, Recovery Period, Terra Firme Forest

iForest 11 (3): 352-359 (2018) - doi: 10.3832/ifor2534-011
https://iforest.sisef.org/contents/?id=ifor2534-011

Research Articles: Photosynthesis of three evergreen broad-leaved tree species, Castanopsis sieboldii, Quercus glauca, and Q. myrsinaefolia, under elevated ozone

Watanabe M, Kinose Y, Izuta T — 2018-05-04

Watanabe M, Kinose Y, Izuta T

PHOTOSYNTHESIS OF THREE EVERGREEN BROAD-LEAVED TREE SPECIES, CASTANOPSIS SIEBOLDII, QUERCUS GLAUCA, AND Q. MYRSINAEFOLIA, UNDER ELEVATED OZONE

Abstract: The main goal of this study was to obtain detailed information on photosynthetic responses of evergreen broad-leaved tree species to ozone (O3). For this, two-year-old seedlings of Castanopsis sieboldii, Quercus glauca, and Q. myrsinaefolia were grown for one growing season, from 15 May to 27 October 2014 under three levels of gas treatments, charcoal-filtered air and 1.0 time and 1.5 times ambient O3 concentrations. We analysed the intercellular CO2 concentration-response curve of the net photosynthetic rate, i.e., the A/Ci curve, in July and October, and growth measurement was carried out at the end of the experiment in October. We observed a difference in O3 susceptibility among the species. Negative effects of O3 were observed on the growth and photosynthetic traits of C. sieboldii, while no significant effects on these traits were noted in the two Quercus species. The decrease in light-saturated net photosynthetic rate (Asat) of C. sieboldii under elevated O3 was accompanied with a significant decrease in the maximum rate of carboxylation (Vcmax). Decreases of leaf nitrogen content and nitrogen use efficiency to Rubisco are considered as factors contributing to lower Vcmax in C. sieboldii seedlings under elevated O3. In addition to the decrease in Vcmax, O3 exposure induced marginal increase of stomatal limitation of photosynthesis. These results indicate that both biochemical and diffusion processes in photosynthesis are responsible for the decrease in Asat of C. sieboldii under elevated O3.

Keywords: Ozone, Photosynthesis, Biochemical Limitation of Photosynthesis, Stomatal Closure, Evergreen Broad-leaved Tree Species

iForest 11 (3): 360-366 (2018) - doi: 10.3832/ifor2493-011
https://iforest.sisef.org/contents/?id=ifor2493-011

Research Articles: Wildfire risk and its perception in Kabylia (Algeria)

Sahar O, Leone V, Limani H, Rabia N, Meddour R — 2018-05-04

Sahar O, Leone V, Limani H, Rabia N, Meddour R

WILDFIRE RISK AND ITS PERCEPTION IN KABYLIA (ALGERIA)

Abstract: This research aims to study wildfire perception by residents living in Wildland Urban Interface (WUI) in Kabylia (Algeria). We conducted an exploratory qualitative survey contacting 254 randomly selected individuals in eight hamlets of the Mizrana forest. Face-to-face questionnaires were administered to understand the fire risk problem. Respondents think that their homes are not exposed to fire risk and perceive their hamlets are protected against wildfires; on the contrary, they perceive their property (fields, livestock, olive trees, etc.) as exposed to fire risk. The vast majority of respondents declare to know how to defend themselves in the case of a fire event, using water and hand tools. Residents mainly use fire for stubble burning and disposal of domestic waste. Their skill in using fire as a land management tool respectively comes from their fathers, grandfathers and mothers. Results show the necessity of making resident more aware of the risks that wildfires pose to them. A culture of risk needs to be developed within the territory to limit vulnerability and the likelihood of destructive fires.

Keywords: Algeria, Fire Use, Mizrana Forest, Risk Perception, TEK, Wildland Urban Interface, Wildfire

iForest 11 (3): 367-373 (2018) - doi: 10.3832/ifor2546-011
https://iforest.sisef.org/contents/?id=ifor2546-011

Research Articles: Outlook of the European forest-based sector: forest growth, harvest demand, wood-product markets, and forest carbon dynamics implications

Jonsson R, Blujdea VN, Fiorese G, Pilli R, Rinaldi F, Baranzelli C, Camia A — 2018-04-18

Jonsson R, Blujdea VN, Fiorese G, Pilli R, Rinaldi F, Baranzelli C, Camia A

OUTLOOK OF THE EUROPEAN FOREST-BASED SECTOR: FOREST GROWTH, HARVEST DEMAND, WOOD-PRODUCT MARKETS, AND FOREST CARBON DYNAMICS IMPLICATIONS

Abstract: A comprehensive assessment of European forest-based biomass harvest potentials, their future utilization and implications on international wood product markets and forest carbon dynamics requires the capability to model forest resource development as well as global markets for wood-based commodities with sufficient geographical and product detail and, most importantly, their interactions. To this aim, we apply a model framework fully integrating a European forest resource model and a global economic forest sector model. In a business-as-usual (BaU) scenario, European Union harvests increase seven percent by 2030 compared to past levels (485 million m3 on 2000-2012 average and 517 million m3 in 2030). The subsequent annual carbon stock change is a ten percent reduction by 2030 compared to 2000-2012 average (equal to 119.3 Tg C yr-1), corresponding to decreasing carbon-dioxide removal by the European forests. A second, high mobilization scenario (HM), characterized by the full utilization of the potential wood supply and a doubling of EU wood pellets consumption, was designed to explore potential impacts on forest carbon dynamics and international wood product markets under intensive exploitation of biomass resources. In the HM scenario, harvest increases by 55% (754 million m3 in 2030) compared to the BaU scenario. Fuelwood accounts for this increase in harvest levels as overall competition effects from increased wood pellets consumption outweighs synergies for material uses of wood, resulting in slightly reduced harvests of industrial roundwood. As expected, this increasing harvest level would significantly impair carbon-dioxide forest sequestration from the atmosphere in the medium term (-83% in 2030, compared to 2000-2012 average).

Keywords: Biomass, Carbon Stock Change, Forest, Fuelwood, Harvest, Wood-based Products

iForest 11 (2): 315-328 (2018) - doi: 10.3832/ifor2636-011
https://iforest.sisef.org/contents/?id=ifor2636-011

Research Articles: Richness and abundance of granivorous vertebrates determine acorn removal patterns in a human modified oak forest

Barragán F, Badano EI, Douterlungne D, Flores J — 2018-04-18

Barragán F, Badano EI, Douterlungne D, Flores J

RICHNESS AND ABUNDANCE OF GRANIVOROUS VERTEBRATES DETERMINE ACORN REMOVAL PATTERNS IN A HUMAN MODIFIED OAK FOREST

Abstract: Most forests of the Earth have been affected by human activities and this can alter the plant-animal interactions on which depend the functional integrity of these ecosystems. In this study, we assessed the relationships between acorn removal rates and the richness and abundance of granivorous vertebrates along a forest-edge-clearing gradient. We also evaluated whether removal rates differed among oak species with different acorn size. To this purpose, a field experiment was performed including acorns of five oak species, which were exposed to seed consumers in the three different habitats (forest interior, man-made clearings and the edge between these habitats). The experimental units consisted in five paper trays containing 50 acorns of each oak species located at different distances from the edge towards the forest and the man-made clearing (0, 20 and 50 m). Experimental sites were equipped with phototraps to record the identity of the visiting granivorous vertebrates. Richness and abundance of granivores increased from the edge towards the forest interior, while the converse patterns were observed in the man-made clearing. For most oak species, acorn removal patterns was positively correlated with richness and abundances of granivores, though in all habitats small-sized acorns were removed much faster and in larger proportions than big-sized acorns. Although these results are specific for the study site, they suggest that man-made clearings reduce the richness and abundance of granivores, thus negatively affecting the secondary dispersion of zoochoric tree species towards open habitats. Further, it also seems that large-seeded oak species face greater dispersal limitations than small-seeded oaks, because of the lack of animals able to scatter them from the forest to the clearings.

Keywords: Acorn Size, Forest Gaps, Land Use Change, Man-made Clearing, Species Diversity

iForest 11 (2): 329-337 (2018) - doi: 10.3832/ifor2216-011
https://iforest.sisef.org/contents/?id=ifor2216-011

Research Articles: Molecular evidence of bidirectional introgression between Quercus suber and Quercus ilex

López De Heredia U, Sánchez H, Soto A — 2018-04-18

López De Heredia U, Sánchez H, Soto A

MOLECULAR EVIDENCE OF BIDIRECTIONAL INTROGRESSION BETWEEN QUERCUS SUBER AND QUERCUS ILEX

Abstract: Cork oak and holm oak share a large part of their natural range, and are known to hybridize in mixed stands. This hybridization is supposed to have played a relevant role in the past history of cork oak. Previous research has reported that F1 hybrids are produced with holm oak acting as pollen recipient, therefore carrying holm oak chloroplast. Additionally, F1 hybrids have been assumed to be pollinated mostly by cork oak. Continued backcrossing of F1 hybrids with cork oak (supported by flowering phenology) could have created the organellar introgression patterns observed nowadays in Eastern Spain and Southern France cork oak populations. On the contrary, no organellar introgression has been detected in holm oak and multiple generation backcross individuals to holm oak have not been reported so far. In this work, we examined whether hybrids preferentially backcross with cork oak or with holm oak. To reach this goal, we genotyped by using eight microsatellite loci the progeny of four cork and four holm oak trees (33 and 44 half-siblings, respectively), and of four hybrids (468 half-siblings) collected over three years from a natural mixed population. We used the STRUCTURE software to estimate the proportion of the genotype of each seedling inherited from cork oak (qs) or from holm oak (qi). The ratio of the offspring q value over the mother q value helped determine the source of pollen that originated each acorn. Our results show for the first time that hybrid trees can be effectively pollinated by both parental species. Additionally, each hybrid tree was predominantly pollinated by the most abundant oak species in its vicinity. These results confirm the occurrence of bidirectional introgression, previously suggested for adult hybrid trees in the field, and point out the pattern of introgression in the seedlings could be most affected by the abundance of the parental species.

Keywords: Cork Oak, Holm Oak, Hybridization, Introgression, Microsatellites

iForest 11 (2): 338-343 (2018) - doi: 10.3832/ifor2570-011
https://iforest.sisef.org/contents/?id=ifor2570-011

Research Articles: Effects of traditional forest management on carbon storage in a Mediterranean holm oak (Quercus ilex L.) coppice

Sferlazza S, Maetzke FG, Iovino M, Baiamonte G, Palmeri V, La Mela Veca DS — 2018-04-18

Sferlazza S, Maetzke FG, Iovino M, Baiamonte G, Palmeri V, La Mela Veca DS

EFFECTS OF TRADITIONAL FOREST MANAGEMENT ON CARBON STORAGE IN A MEDITERRANEAN HOLM OAK (QUERCUS ILEX L.) COPPICE

Abstract: In the last decade, there has been increased interest in measuring and modeling storage in the five forest carbon pools: the aboveground and belowground biomass (living biomass), the deadwood and litter (dead biomass), and the soil (soil organic matter). In this paper, we examined carbon storage in a holm oak coppice stand in the Madonie Mountains in Sicily (Italy), which is a typical case of managed coppice stands. Today, traditional coppice practices are only applied to a small number of forested areas in Sicily, such as the selected site, because of the decline in demand for wood and charcoal. The dendrometric parameters of the stands were recorded, and silvicultural indices were calculated immediately after cutting as well as during and at the end of the rotation period; they showed the trends typical of coppices. The carbon stocks in the five carbon pools were quantified to investigate the effects of coppicing on carbon storage in this Mediterranean area. Results showed that the lowest living biomass values were observed in the first years following coppicing, except for litter carbon. Belowground biomass and the soil carbon stock did not vary significantly with coppicing. During the rotation period, the aboveground biomass was completely restored, and the balance of the carbon stocks indicates that coppicing is a sustainable forest management choice from the point of view of the carbon balance, given that the logged trees are generally used for bioenergy production.

Keywords: Carbon Pool, Aboveground Carbon, Belowground Carbon, Dead Carbon, Litter Carbon, Soil Carbon, Coppicing

iForest 11 (2): 344-351 (2018) - doi: 10.3832/ifor2424-011
https://iforest.sisef.org/contents/?id=ifor2424-011

Research Articles: Patterns of genetic variation in bud flushing of Abies alba populations

Mihai G, Mirancea I, Birsan MV, Dumitrescu A — 2018-04-13

Mihai G, Mirancea I, Birsan MV, Dumitrescu A

PATTERNS OF GENETIC VARIATION IN BUD FLUSHING OF ABIES ALBA POPULATIONS

Abstract: In the spring of 2007, 51 full-sib and six half-sib families of European silver fir were obtained through controlled and open pollinations from the same clones in a seed orchard. Genetic variation and parameters for bud flushing were determined in two progeny tests established in a nursery. The results indicate a high genetic control of bud flushing of European silver fir. Both the additive and the dominance genetic variances were major sources of genetic variation. The additive genetic variance was greater for open-pollinated than for full-sib progeny, representing 50-95% of phenotypic variance. Narrow-sense individual heritability estimates for control-pollinated progenies ranged from 0.14 to 0.64, while the full-sib family heritability ranged from 0.09 to 0.40. In the open-pollinated progenies, the values of individual and family heritability were higher than those in control-pollinated progeny and ranged from 0.50 to 0.95 for both. In both experiments, genetic parameters were higher for bud flushing at the beginning of the growing period than at later stages. The genetic correlations between bud phenology and growth traits were positive and significant in control-pollinated progeny but not significant in open-pollinated progeny. Positive significant correlations between control-pollinated and open-pollinated progeny showed a maternal effect. Bud flushing was negatively correlated with geographic and climatic parameters of the site of parents’ origin, accounting for 83-97% of the total variation of this adaptive trait.

Keywords: Bud Flushing, Climatic Parameters, Correlations, Genetic Parameters, Genetic Variation, Silver Fir

iForest 11 (2): 284-290 (2018) - doi: 10.3832/ifor2314-011
https://iforest.sisef.org/contents/?id=ifor2314-011

Research Articles: Some refinements on species distribution models using tree-level National Forest Inventories for supporting forest management and marginal forest population detection

Marchi M, Ducci F — 2018-04-13

Marchi M, Ducci F

SOME REFINEMENTS ON SPECIES DISTRIBUTION MODELS USING TREE-LEVEL NATIONAL FOREST INVENTORIES FOR SUPPORTING FOREST MANAGEMENT AND MARGINAL FOREST POPULATION DETECTION

Abstract: Spatial modelling is a fundamental tool to support forest management strategies. National Forest Inventories (NFIs) provide extensive and detailed data for spatial analysis. In this study, the most recent Italian NFI (INFC2005) was used to evaluate possible refinements on species distribution model (SDM) techniques and to derive the future scenarios for two target species (Fagus sylvatica L. and Abies alba Mill.) sharing a similar ecological environment and geographic range. A weighted SDM and a provenance distribution model (PDM) were tested, based on tree-level selection of NFI plots using species basal area as a filter. Two climate projections were analysed for 2050s according to the IPCC 5th Assessment Report (AR5). The results were evaluated as possible guidelines for management of the Italian region of the EUFGIS network, where many marginal forest populations (MaPs) are currently included as genetic conservation units (GCUs). The uncertainty of coordinates of inventory points did not affect the results of SDM. No statistical differences were found when comparing the niche realization for the two model species (ANOVA p>0.05) mainly due to spatial autocorrelation between the environmental predictors. Based on the classic SDM evaluation method (True Skill Statistic - TSS) little improvements in predictions were observed when weighting each presence/absence records, possibly due to the lack of adequate ancillary data but also to the evaluation method. A higher accuracy of predictions (TSS>0.85) was obtained when different “provenances” were modelled separately, due to the reduction in the “background noise”. We showed that for classical SDM, the prevalence of certain ecological features of some locations may drive algorithms to produce coarse averaged predictions. Provenance distribution modelling may represent a valuable step forward in spatial analysis, particularly for the detection of marginal peripheral populations. The exact spatial co-ordinates of plots and additional information on site quality (e.g., stand age, site index, etc.) in NFI data could greatly help in better weighting presence/absence data and properly test the new evaluation methods.

Keywords: INFC2005, European Beech, Silver Fir, Modelling Uncertainties, Provenance Modelling, Climate Change, Mediterranean Area

iForest 11 (2): 291-299 (2018) - doi: 10.3832/ifor2441-011
https://iforest.sisef.org/contents/?id=ifor2441-011

Research Articles: Stand structure and regeneration of Cedrus libani (A. Rich) in Tannourine Cedar Forest Reserve (Lebanon) affected by cedar web-spinning sawfly (Cephalcia tannourinensis, Hymenoptera: Pamphiliidae).

2018-04-13

Bassil S, Kattar S, Navarro-Cerrillo RM, Navarrete Poyatos M&, Nemer N, Palacios Rodríguez G

STAND STRUCTURE AND REGENERATION OF CEDRUS LIBANI (A. RICH) IN TANNOURINE CEDAR FOREST RESERVE (LEBANON) AFFECTED BY CEDAR WEB-SPINNING SAWFLY (CEPHALCIA TANNOURINENSIS, HYMENOPTERA: PAMPHILIIDAE).

Abstract: The analysis of forest structure is a useful tool to understand stand biodiversity characterizing forest ecosystems, and could help in suggesting appropriate management plans. Cedar forests in Lebanon are remnant patches that survived past human activities but are still threatened by other different anthropogenic and natural disturbances. Among these threats, the cedar web-spinning sawfly (Cephalcia tannourinensis) discovered in Tannourine Cedar Forest Nature Reserve in 1997, which is able to cause the death of trees. The aim of this study is to investigate the impact of this pest on the stand structure and regeneration of Cedrus libani in Tannourine Cedar Forest Nature Reserve located in North Lebanon. The dependence of stand structural attributes (diameter at breast height, total height and basal area) on the presence of infestation by the cedar web-spinning sawfly was identified using the Student’s t-test. The Ripley’s K(d) function was used to analyse the spatial pattern of cedar stands. In addition, the diameter, the vertical structure and the crown projection were characterized using the Weibull function and graphic representations. The results showed that stand structure and regeneration are significantly different between infested and non-infested stands. The cedar of Lebanon remains as the dominant species, with abundant young individuals and a good regeneration status (c = 1.0). The analysis of the spatial pattern showed a positive spatial relationship between mature Lebanese cedar trees as well as between mature and juvenile cedars, with a bigger aggregation in infested plots (6 to 10 meters) than in non-infested quadrates (2 to 7 meters), reflecting the impact of the cedar web-spinning sawfly on the stand structure and regeneration of Cedrus libani stands.

Keywords: Cedrus libani, Stand Dynamic, Pest Damage, Spatial Pattern, Vertical Structure, Cephalcia tannourinensis

iForest 11 (2): 300-307 (2018) - doi: 10.3832/ifor2502-011
https://iforest.sisef.org/contents/?id=ifor2502-011

Research Articles: Regeneration dynamics in the laurel forest: changes in species richness and composition

2018-04-13

Arévalo JR, De Nascimento L, Fernández-Lugo S, Méndez J, González-Delgado G, Balguerías E, Gomes Pereira Cabral E, Fernández-Palacios JM

REGENERATION DYNAMICS IN THE LAUREL FOREST: CHANGES IN SPECIES RICHNESS AND COMPOSITION

Abstract: The recovery and survival of the Macaronesian laurel forest depends on its regeneration strategies. After years of long-term monitoring, both sexual and asexual regeneration appear to be equally important. However, the mechanisms for each are just beginning to be understood. In order to contribute to the understanding of the laurel forest sexual regeneration, we analyzed the species composition of the seedling bank every two weeks over three years in the laurel forest of Anaga (Tenerife, Canary Islands). We compared the species compositions of the seedling bank with the canopy, and analyzed changes in their diversity over this period in different forest stands. We found that species diversity (evenness) is different among plots regardless of the stand. In some cases, plot diversity remained constant over time, while others showed some variations, which were little related to climatic conditions (temperature and precipitation). We also found no relationship between the seedling bank and canopy composition, with shade-intolerant species being more abundant in the former. Although climatic conditions remained constant during the period and other environmental conditions did not vary either, some changes were found in the seedling bank species composition. These were related to the increased degree of conservation of the laurel forest of Anaga (by closing unpaved roads, limiting access, and the abandonment of agriculture) that had negatively affected the density of shade-intolerant species. We suggest that such conservation measures should be maintained and extended to other areas where agriculture has been recently abandoned to allow the potential establishment of laurel forest and late successional species.

Keywords: Conservation, Evenness, Regeneration, Seedling Bank, Species Composition

iForest 11 (2): 308-314 (2018) - doi: 10.3832/ifor2580-011
https://iforest.sisef.org/contents/?id=ifor2580-011

Research Articles: Contrasting holm oak provenances show different field performance but similar resilience to drought events eight years after planting in a Mediterranean environment

Andivia E, Natalini F, Fernández M, Alejano R, Vázquez-Piqué J — 2018-03-29

Andivia E, Natalini F, Fernández M, Alejano R, Vázquez-Piqué J

CONTRASTING HOLM OAK PROVENANCES SHOW DIFFERENT FIELD PERFORMANCE BUT SIMILAR RESILIENCE TO DROUGHT EVENTS EIGHT YEARS AFTER PLANTING IN A MEDITERRANEAN ENVIRONMENT

Abstract: Diversification of genetic plant material in forest plantations is viewed as a promising strategy to promote forest adaptation and resilience to ongoing climate change. However, there is an intense debate about whether foreign populations might outperform local ones under new climatic conditions. Unfortunately, long-term experiments using contrasting provenances are scarce, especially in the Mediterranean region. In this context, the evaluation of the resistance and resilience of individuals from different provenances to drought can help to forecast their performance under different climate change scenarios, and therefore to establish guideline regarding plant material selection in reforestation projects. We evaluated the performance (survival and drought) and drought sensitivity of Quercus ilex saplings from two contrasting provenances growing during eight years in a common garden experiment. For this, we used a combination of dendroecological methods and water-relation measurements, such as leaf water potential (Ψpd), cuticular transpiration (Ec), relative water content at the point of stomatal closure (RWCc) and specific leaf area (SLA). We also compared the resilience and resistance, in terms of radial growth to the intense drought event of 2012 between saplings from both provenances. Our results suggest a lack of idiosyncratic physiological response and growth sensitivity to drought between provenances. However, saplings from the drier provenance showed a superior performance in terms of survival and growth. Survival was greater in saplings from the dry provenance (100 vs. 91 %). Mean annual basal area increment was also greater in saplings from the dry provenance (158.8 ± 13.5 vs. 96.2 ± 8.4 mm2), which resulted in greater diameter eight year after planting (47.5 ± 2.8 vs. 38.3 ± 2.3 mm). The lower values of Ψpd, Ec and SLA in the summer of the first two years after planting suggest that climatic conditions after planting rather than isolated drought events was the most critical period for the success of these saplings. In view of our results, the selection of plant material for forest plantation should be carefully evaluated in forest restoration projects, while priority should be given to those actions oriented to increase the early survival of local Q. ilex seedlings.

Keywords: Ecotypes, Quercus ilex, Forest Restoration, Growth Stability, Water-relation, Phenotypic Plasticity, Local Adaptations

iForest 11 (2): 259-266 (2018) - doi: 10.3832/ifor2573-011
https://iforest.sisef.org/contents/?id=ifor2573-011

Research Articles: Growth-climate relations and the enhancement of drought signals in pedunculate oak (Quercus robur L.) tree-ring chronology in Eastern Hungary

Árvai M, Morgós A, Kern Z — 2018-03-29

Árvai M, Morgós A, Kern Z

GROWTH-CLIMATE RELATIONS AND THE ENHANCEMENT OF DROUGHT SIGNALS IN PEDUNCULATE OAK (QUERCUS ROBUR L.) TREE-RING CHRONOLOGY IN EASTERN HUNGARY

Abstract: This paper presents an analysis of the climatic factors affecting tree-ring growth in pedunculate oak (Quercus robur L.), one of the most important species of Hungarian forests. A 221-year oak chronology was elaborated, covering the period 1789 to 2009 AD. The daily climate data for a ~110 year stretch offered a detailed insight into the climate-growth relations. The correlation function reached a maximum (r > 0.4) in the case of precipitation in May-August, providing evidence that water availability is the main factor driving the oak growth in the eastern part of the Great Hungarian Plain. Although there was no significant linear relation with temperature in the long term, moving window correlation analysis revealed that temperature response changed substantially over the course of the 20th century. While positive correlation with winter temperature was characteristic in the first decades, later the response to summer temperature strengthened remarkably, reaching r = -0.569 by the end of the analysed period (years 1978-2007). While the vulnerability of oak to drought stress is common across Europe, in southern and central Europe high summer temperatures impair tree growth. The enhanced sensitivity of pedunculate oaks to the water balance in the eastern part of the Great Hungarian Plain allows to surmise the presence of an evolving tendency towards drought risk and vulnerability in the case of these oak stands.

Keywords: Dendroclimatology, Pedunculate Oak, Tree-rings, Hungary, Drought Signal

iForest 11 (2): 267-274 (2018) - doi: 10.3832/ifor2348-011
https://iforest.sisef.org/contents/?id=ifor2348-011

Research Articles: Alternative methods of scaling Eucalyptus urophylla trees in forest stands: compatibility and accuracy of volume equations

Miguel EP, Péllico Netto S, Azevedo GBD, Azevedo GTDOS, Rezende AV, Pereira RS — 2018-03-29

Miguel EP, Péllico Netto S, Azevedo GBD, Azevedo GTDOS, Rezende AV, Pereira RS

ALTERNATIVE METHODS OF SCALING EUCALYPTUS UROPHYLLA TREES IN FOREST STANDS: COMPATIBILITY AND ACCURACY OF VOLUME EQUATIONS

Abstract: This study developed and tested a procedure that aimed to reduce the cost of forest stand volume estimation. Using a typical 3 x 3 m Eucalyptus urophylla plantation, estimates based on a simplified approach were compared with those of precise but costly reference methods. The simplified approach required measuring the total height and bole diameters up to 2 m high. The volume of the lower part was estimated using Smalian’s formula, while the volume of the upper part was estimated using a simple solid as an approximation. Three typical solids were tested: paraboloid, cone, and neiloid. The approach proposed is non-destructive, because it does not require tree felling, while precise methods are destructive. The operational (traditional) method uses Smalian’s formula to measure bole diameter at short intervals over the whole bole, while the precise, more research-suited (reference) method records water displacement (using a xylometer) to accurately measure the volume of each bole section. The reference and traditional methods, as expected, produced very similar results. The approach proposed, using a paraboloid for the upper part, provided results that were not statistically different to the reference values. The volumes estimated by the proposed approach were used to calibrate the Schumacher-Hall function, and the performance of the model was evaluated using the values obtained by the xylometer.

Keywords: Forest Inventory, Rigorous Scaling, Dendrometric Prototype, Volume Equation, Modeling

iForest 11 (2): 275-283 (2018) - doi: 10.3832/ifor2155-011
https://iforest.sisef.org/contents/?id=ifor2155-011

Research Articles: Optimizing silviculture in mixed uneven-aged forests to increase the recruitment of browse-sensitive tree species without intervening in ungulate population

Ficko A, Roessiger J, Bončina A — 2018-03-12

Ficko A, Roessiger J, Bončina A

OPTIMIZING SILVICULTURE IN MIXED UNEVEN-AGED FORESTS TO INCREASE THE RECRUITMENT OF BROWSE-SENSITIVE TREE SPECIES WITHOUT INTERVENING IN UNGULATE POPULATION

Abstract: An increase in ungulate abundance in Europe in recent decades has raised concerns for the survival of browse-sensitive tree species in its early life history stages. A possible strategy for mitigating the browsing-induced mortality of natural regeneration is to optimize silviculture. We used matrix population models parameterized for three types of Abies alba - Picea abies - Fagus sylvatica forests (3,183 permanent sample plots from three study areas in Slovenia, 39,717 ha), and a non-linear optimization to: (i) schedule optimal timing and intensity of logging in the next 100 years to increase the recruitment of Abies alba without intervening in the population of ungulates; and (ii) examine the influence of different natural recruitment rates on the potential for mitigating recruitment failure through silviculture optimization. The optimal management has required species-, growth- and diameter-specific logging, including intensive logging of large-diameter Abies alba in the first decades and strict conservation of recruits. The potential for mitigating recruitment failure through optimization increased progressively with natural recruitment rate and progressively at a decreasing rate with time. Optimizing silviculture was effective for maintaining Abies alba in stands exposed to low or moderate browsing pressures. Faced with chronic ungulate herbivory, forest managers should primarily focus on the reduction of herbivory and to a lesser extent on optimizing silviculture.

Keywords: Continuous Cover Forestry, Optimization, Natural regeneration, Recruitment, Abies alba

iForest 11 (2): 227-236 (2018) - doi: 10.3832/ifor2567-011
https://iforest.sisef.org/contents/?id=ifor2567-011

Short Communications: Climate effects on growth differ according to height and diameter along the stem in Pinus pinaster Ait.

Rubio-Cuadrado A, Bravo-Oviedo A, Mutke S, Del Río M — 2018-03-12

Rubio-Cuadrado A, Bravo-Oviedo A, Mutke S, Del Río M

CLIMATE EFFECTS ON GROWTH DIFFER ACCORDING TO HEIGHT AND DIAMETER ALONG THE STEM IN PINUS PINASTER AIT.

Abstract: Climate-growth relationships in forest trees are increasingly the focus of research aimed at understanding and assessing responses to climate change. Many studies have been confined to annual radial growth at breast height as an easy-to-measure dendrological standard variable, although its validity as a proxy for overall annual growth patterns in trees has scarcely been addressed. In this study, we test this hypothesis by exploring additional information on climate-growth relationships as well as analyzing both the radial growth at different stem heights and the height increment. For this purpose, past annual radial growth and shoot elongation were measured in 10 dominant Pinus pinaster Ait. trees in a 130-year-old stand. Radial increments were measured on disks taken from five different trunk heights up to 15 meters. Height increments were obtained by measuring the distance between consecutive branch whorls, which appear as knots after sawing a longitudinal section of the stem. The relationships between climate and both radial growth and height increment were analyzed through Pearson’s correlations and the response to extreme climatic episodes was analyzed using resilience indices. Results revealed that the climatic variables affecting growth were different for height and stem diameter. Additionally, in the case of stem diameter, the climatic variables affecting growth also depended on the height at which the sample was taken. Precipitation prior to bud break, both in the year in which the studied shoot elongation takes place and in the previous year, has a positive effect on height increment. Radial growth in the upper part of the stem was mainly influenced by spring temperatures and precipitation, whereas in the case of basal radial growth it was the autumn and winter temperatures and precipitation of the previous year to growth which had the greatest influence. Similarly, severe droughts cause greater decline in height increment, while the decline in radial growth of the upper part of stem is smaller than that of radial growth at breast height. In conclusion, the analysis of height increment and upper radial growth provides important information to complement the dendroclimatology data for radial growth at breast height, thus improving our understanding of the impact of climate change on tree growth.

Keywords: Dendrochronology, Climate Growth Response, Growth Allocation, Stem Analysis, Climate Sensitivity, Resilience

iForest 11 (2): 237-242 (2018) - doi: 10.3832/ifor2318-011
https://iforest.sisef.org/contents/?id=ifor2318-011

Research Articles: Hydrological properties of litter layers in mixed forests in Mt. Qinling, China

Chen S, Cao T, Tanaka N, Gao T, Zhu L, Zou CB — 2018-03-12

Chen S, Cao T, Tanaka N, Gao T, Zhu L, Zou CB

HYDROLOGICAL PROPERTIES OF LITTER LAYERS IN MIXED FORESTS IN MT. QINLING, CHINA

Abstract: The litter layer is an important component of forest ecosystems, although little is known about the differences in litter characteristics and hydrological properties of unmanaged, overgrown broadleaved and coniferous mixed forests in the subtropical and temperate zones. This study was carried out in a naturally generated broadleaved and coniferous mixed forest at the Qinling National Forest Ecosystem Research Station, Shaanxi Province, China. We quantified the litter thickness, mass, and its hydrological properties in evergreen pine (Pinus tabulaeformis) stands and deciduous oak (Quercus aliena var. acuteserrata) stands through in situ surveys and laboratory immersion experiments. The thickness of the litter layer for P. tabulaeformis averaged 9.3 ± 2.8 cm, and it was not significantly different from that detected in the Q. aliena stand (8.3 ± 3.6 cm). The total mass of the litter layer for P. tabulaeformis, 27.94 ± 9.81 Mg ha-1, was significantly higher than the total mass of 16.04 ± 3.60 Mg ha-1 found for Q. aliena. The mass of the semi-decomposed, fermented litter (OF) layer was significantly higher than that of the non-decomposed litter (OL) layer, irrespective of species. The rate of water absorption by dry litter was the highest at the onset of the immersion experiment and decreased exponentially with time. The water-holding capacity (Wm) and water-interception capacity (Wi) of the OF layer were higher than the OL layer for both forest stands. The Wm and Wi for the P. tabulaeformis stand were higher than those for the Q. aliena stand at our study sites. The higher Wm and Wi for P. tabulaeformis may be more effective in ameliorating the splash impact from high-intensity storms to improve water quality, while relatively lower Wm and Wi for Q. aliena may be considered favorable for augmenting water yield. Forest resource managers should consider those differences along with the other components of the water budget when making management decisions.

Keywords: Water Conservation Forest, Hydrological Properties, Forest Succession

iForest 11 (2): 243-250 (2018) - doi: 10.3832/ifor2535-011
https://iforest.sisef.org/contents/?id=ifor2535-011

Research Articles: Can bark stripping cause red heartwood formation in beech stems?

Račko V, Mišíková O, Hlaváč P, Deáková V — 2018-03-12

Račko V, Mišíková O, Hlaváč P, Deáková V

CAN BARK STRIPPING CAUSE RED HEARTWOOD FORMATION IN BEECH STEMS?

Abstract: Injuries to standing trees caused by logging and the subsequent changes in biochemical composition and anatomy of affected tissues lead to wood quality loss, thus lowering the commercial value of roundwood. In this study, we investigated the influence of various factors that could help mitigate or prevent the spread of infections in the stem caused by injuries. A total of 112 beech logs (tree age: 42-143 years) from ten forest stands at three different sites in central Slovakia were examined, and the extent of discolouration and decay zones in each stem was measured, along with cambial age, stem diameter, injury width, and injury closure period. The results showed that the width of physiologically active wet sapwood and the width of the inactive dehydrated zone in the stem are important factors influencing red heartwood formation. We found no significant differences in the extent of discolouration and decay among different stands and sites. Stem diameter and injury width did significantly affect the penetration of infection through sapwood, and red heartwood formation was significantly affected by cambial age and injury width, while stand age, site slope, beech proportion in the stand and injury closure did not show any significant effect. Binary logistic models were applied to assess the probability of pathogen penetration through sapwood into the stem dehydrated zone as a function of injury width and stem diameter, as well as the probability that this could lead to red heartwood formation based on injury width and cambial age of beech stems.

Keywords: Sapwood Width, Dehydrated Zone Width, Discoloration Depth, Decay Depth, Red Heartwood Formation

iForest 11 (2): 251-258 (2018) - doi: 10.3832/ifor2147-011
https://iforest.sisef.org/contents/?id=ifor2147-011

Research Articles: Multi-temporal influence of vegetation on soil respiration in a drought-affected forest

Barba J, Lloret F, Poyatos R, Molowny-Horas R, Yuste JC — 2018-03-01

Barba J, Lloret F, Poyatos R, Molowny-Horas R, Yuste JC

MULTI-TEMPORAL INFLUENCE OF VEGETATION ON SOIL RESPIRATION IN A DROUGHT-AFFECTED FOREST

Abstract: Aboveground plant activity influences fine roots and rhizosphere activity, which is reflected on soil respiration (SR). However, it is still unclear and poorly understood the nature of plant activity control over SR, especially under drought conditions. We studied the plant activity-SR relationship at different timescales in a water-limited mixed Mediterranean forest where Scots pines (Pinus sylvestris L.) are undergoing drought-induced die-off and are being replaced by the more drought-resistant Holm oak (Quercus ilex L.). Half-hourly sap flow (SF), as a proxy of photosynthesis, coupled with measures of SR using solid-state CO2 sensors, were monitored during nine months in four different trees, representative of the diversity and health condition of the forest. SF was strongly associated with SR at both daily and seasonal timescales. At daily timescales, almost no lags were found between SF and SR, indicating a fast control of photosynthesis on SR. However, the association between SF and SR weakened during the summer drought. These temporal patterns were not constant across the trees representing the die-off and replacement processes. SR beneath living pines was highly controlled by SF at daily scale, whereas Holm oak seemed to be more controlled by SF at seasonal scale. The relationship between SF and SR measured beneath dead pine and Holm oak at the daily and seasonal scales was consistent with the colonization of soil gaps by holm oak roots following Scots pine death and suggests that surviving Scots pines are unable to expand their root system in these gaps. Our results collectively show how drought modulates the link between canopy photosynthesis and soil respiration, and increase our understanding on how belowground processes may be affected by the successional dynamics following drought-induced forest mortality.

Keywords: Soil Respiration, Sap Flow, Scots Pine (Pinus sylvestris), Holm Oak (Quercus ilex), Drought, Die-off, Functional Colonization, Mediterranean Ecosystem

iForest 11 (2): 189-198 (2018) - doi: 10.3832/ifor2448-011
https://iforest.sisef.org/contents/?id=ifor2448-011

Research Articles: Comparison of soil CO2 emissions between short-rotation coppice poplar stands and arable lands

Ferré C, Comolli R — 2018-03-01

Ferré C, Comolli R

COMPARISON OF SOIL CO2 EMISSIONS BETWEEN SHORT-ROTATION COPPICE POPLAR STANDS AND ARABLE LANDS

Abstract: Bioenergy crops are considered to have the potential for climate mitigation and socio-economic benefits owing to their capacity to sequester C and partially replace the consumption of fossil fuels. In this study, the effects on soil respiration of a recent conversion of arable land to high (H) and very high (VH) density short-rotation coppices (SRCs), as well as of agronomic treatments (fertilization with or without irrigation) and lane/row location, were investigated in an alluvial area in Italy. A survey of soil variability was carried out by collecting soil cores (0-60 cm depth) at 67 points to characterize surface and subsurface spatial distributions of pH, organic carbon, nitrogen and carbonates and identify comparable points for monitoring soil respiration. Soil CO2 emissions were monitored over the period April 2010-November 2011 at 27 locations covering the whole study site. The influence of land use (H-SRC, VH-SRC, corn and alfalfa) or treatments on soil respiration was evaluated considering both factors as fixed effects in a linear mixed model. Our results showed that (i) the high variability of soil properties even at small spatial scale has to be considered when selecting points for monitoring soil respiration in the field; (ii) the cumulative soil respiration over the study period at the VH-SRC was lower (1299 ± 30 g C m-2) than in croplands (1600 ±145 g C m-2) and higher along the rows than in the lanes; (iii) no significant differences in soil respiration were found between the H-SRC and corn field; (iv) two years after VH-SRC establishment, agronomic treatments did not appear to influence soil respiration; (v) land-use change affected the vertical soil organic carbon distribution and soil surface temperature, as reflected in soil respiration differences.

Keywords: Land-use Change, Soil Spatial Variability, Soil Respiration, Short-rotation Coppice, Cropland, Mixed Model

iForest 11 (2): 199-205 (2018) - doi: 10.3832/ifor2621-010
https://iforest.sisef.org/contents/?id=ifor2621-010

Research Articles: Belowground biomass models for young oligotrophic Scots pine stands in Latvia

Kenina L, Bardulis A, Matisons R, Kapostins R, Jansons A — 2018-03-01

Kenina L, Bardulis A, Matisons R, Kapostins R, Jansons A

BELOWGROUND BIOMASS MODELS FOR YOUNG OLIGOTROPHIC SCOTS PINE STANDS IN LATVIA

Abstract: The increasing interest in carbon budget estimation and the growing use of woody biomass in bioenergy production raises the necessity for precise estimates of belowground biomass and soil carbon pools in forest ecosystems, particularly in terms of changes in the age structure of forests. The aim of this study was to estimate the belowground biomass of young (< 40 years) stands of Scots pine (Pinus sylvestris L.) in Latvia. The biomass of small roots (diameter 2-20 mm), coarse roots (diameter > 20 mm), and stumps of 39 trees from eight stands growing on dry, nutrient-poor mineral soils was measured and compared to the aboveground variables of sampled trees. The results revealed that stumps, small roots, and coarse roots comprised 43%, 35% and 22%, respectively, of the belowground biomass of young Scots pines. The proportion of belowground biomass over the total tree biomass was age-dependent, ranging from 33% to 17% for 8-year and 40-year old trees, respectively. Aboveground tree variables were significantly correlated with the belowground biomass, being stemwood volume and basal area the best predictors (R2 = 0.86-0.98, relative errors = 26-43%) of the belowground biomass components. Accordingly, the developed models produced more accurate estimates compared to previous models for the region, thus reducing the uncertainty in determining the carbon budget for belowground biomass. Still, an analysis of a more comprehensive dataset is needed to account for the effect of the social status of trees, as well as the within- and between-stand variation.

Keywords: Hemiboreal Forests, Europe, Pinus sylvestris, Allometric Equation, Coarse Roots, Total Root Biomass

iForest 11 (2): 206-211 (2018) - doi: 10.3832/ifor2553-010
https://iforest.sisef.org/contents/?id=ifor2553-010

Research Articles: Effect of drought stress on some growth, morphological, physiological, and biochemical parameters of two different populations of Quercus brantii

Jafarnia S, Akbarinia M, Hosseinpour B, Modarres Sanavi SAM, Salami SA — 2018-03-01

Jafarnia S, Akbarinia M, Hosseinpour B, Modarres Sanavi SAM, Salami SA

EFFECT OF DROUGHT STRESS ON SOME GROWTH, MORPHOLOGICAL, PHYSIOLOGICAL, AND BIOCHEMICAL PARAMETERS OF TWO DIFFERENT POPULATIONS OF QUERCUS BRANTII

Abstract: In recent years, drought-induced tree mortality has occurred in the oak forests of the Zagros Mountains (western Iran). The impacts of climate change induced by drought stress have been most acutely experienced by two populations of Persian oaks (Quercus brantii Lindl) grown in the western provinces (Ilam and Lorestan) of the Zagros region. We surveyed growth, physiological, and biochemical responses of one-year-old Persian oak seedlings from Melasyah (Ilam) and Chegeni (Lorestan) provenances, which were subjected to three watering regimes (100%, 40%, and 20% of field capacity) in a greenhouse. The severe drought stress decreased the diameter and height growth, total biomass, net photosynthesis, gas exchange, xylem water potential, maximum Rubisco activity (Vcmax) as well as the maximum PSII photochemical efficiency of the oak seedlings in both populations, but the rate of decrease was greater in Chegeni seedlings as compared to Melasyah seedlings. Although proline and soluble sugar contents significantly increased in response to drought in both populations under stress, the rate of increase was higher in Melasyah seedlings as compared to Chegeni seedlings. In addition, the activities of peroxidase, superoxide dismutase, catalase, and ascorbic peroxidase as well as that of phenylalanine ammonia lyase were promoted in both populations under drought stress. However, the incremental rate was higher in the Melasyah population than in the Chegeni population. Under severe drought stress, the MDA content, electrolyte leakage, the content of hydrogen peroxide, and superoxide radical significantly increased in both the populations. The rate of increase, however, was higher in the Chegeni population. Under drought stress, the total phenol and flavonoid contents of Melasyah seedlings were higher than those of Chegeni seedlings. The results showed that Chegeni seedlings are more sensitive than Melasyah seedlings when exposed to a water limitation stress. Our findings suggest that the climate conditions of the Persian oak stands should be considered by nursery managers while creating establishment and restoration programs.

Keywords: Drought Stress, Persian Oak, Zagros Mountain, Provenance, Drought Resistance

iForest 11 (2): 212-220 (2018) - doi: 10.3832/ifor2496-010
https://iforest.sisef.org/contents/?id=ifor2496-010

Research Articles: The effect of calcium on the growth of native species in a tropical forest hotspot

2018-03-01

Gonçalves Bizuti DT, Casagrande JC, Soares MR, Sartorio SD, Brugnaro C, Gomes César R

THE EFFECT OF CALCIUM ON THE GROWTH OF NATIVE SPECIES IN A TROPICAL FOREST HOTSPOT

Abstract: Recovering of degraded areas depends not only on the choice of native species to be planted, but also on the requirements of planted seedling species in terms of soil fertility, mainly in tropical areas. This study aims to assess the effects of calcium (Ca) and soil base saturation (V%) on the growth of seedlings of eight tree species native to the Atlantic Forest biome and commonly used in restoration plantings in the study region. Seedlings were grown in a greenhouse over a period of four months in Haplic Arenosol dystric soil with low calcium content and high aluminum saturation, and were subjected to four different treatments: (i) control; (ii) lime addition until V%=40 (V40); (iii) lime addition until V%=70 (V70); (iv) addition of calcium chloride and magnesium until V%=70 (VMg70). On average, seedlings treated only with lime (V40 and V70) gave similar results, showing an increase in both shoot and root dry plant biomass. Different absorption by species belonging to different successional groups were observed. Pioneer and early secondary species showed similar behavior regarding nutrient use efficiency. Seedling fertilization increases the chances of success of restoration plantings in degraded areas by favoring seedling biomass gain and nutrient absorption, and increasing overall V% through lime fertilization. The patterns for pioneer and secondary species found in this study could contribute to decision making in restoration projects and to native seedling production of white-sand forest native species.

Keywords: Tree Species, Plant Nutrition, Liming, Nutrient Absorption Efficiency, Ecological Restoration

iForest 11 (2): 221-226 (2018) - doi: 10.3832/ifor2074-010
https://iforest.sisef.org/contents/?id=ifor2074-010

Research Articles: Monitoring of changes in woodlots outside forests by multi-temporal Landsat imagery

Rahman MM, Islam MS, Pramanik MAT — 2018-02-19

Rahman MM, Islam MS, Pramanik MAT

MONITORING OF CHANGES IN WOODLOTS OUTSIDE FORESTS BY MULTI-TEMPORAL LANDSAT IMAGERY

Abstract: Woodlots outside forests play a significant role in diversifying household income, reducing poverty, supplying timber and fuel-wood, and regulating the local environment in many countries with low forest cover. This study aimed to develop a method for delineating the spatial footprint of woodlots outside forests and assessing their changes over time. The test site was located in the Jhalokati District of south-western Bangladesh, one of the world’s most densely populated regions. Landsat images from 2010 were classified using a supervised method. Woodlots were extracted, converted to vector layers, and manually edited. The overall accuracy of the 2010 land cover map was 87%-89%. A change vector layer was generated by further updating of the vector layer by overlaying a 1989 Landsat image. The total coverage of woodlots in the district increased between 1989 and 2010, from 19.638 ha (27%) to 27.836 ha (39%). The study identified two primary reasons for changes in woodlot coverage: (i) woodlot expansion associated with the population growth and establishment of new households; and (ii) conversion of cropland to orchards because of economic reasons. The results will improve understanding of the spatial distribution of woodlot coverage in the study area and their dynamics over time.

Keywords: Woodlot, Trees Outside Forests (TOF), Landsat, Change, Mapping

iForest 11 (1): 162-170 (2018) - doi: 10.3832/ifor2021-010
https://iforest.sisef.org/contents/?id=ifor2021-010

Research Articles: A Decision Support System for trade-off analysis and dynamic evaluation of forest ecosystem services

Sacchelli S — 2018-02-19

Sacchelli S

A DECISION SUPPORT SYSTEM FOR TRADE-OFF ANALYSIS AND DYNAMIC EVALUATION OF FOREST ECOSYSTEM SERVICES

Abstract: This paper presents an open-source Decision Support System (DSS) able to quantify the economic value of forest ecosystem services and their dynamic trade-offs. Provisioning, regulation and support services, as well as cultural services, can be evaluated by the model. Best management forestry practices can be identified by optimizing specific objective functions, e.g., maximizing the economic value or identifying the ideal rotation period. The model was applied to a silver fir (Abies alba Mill.) stand in central Italy as a case study. Results show the importance of economic parameters (e.g., discount rate) and management practices (e.g., presence/absence of silvicultural thinning) in defining forest values. The main strengths and weaknesses of the DSS are discussed in light of its potential for application in the sector of Payment for Ecosystem Services.

Keywords: Ecosystem Services Planning, Complex Systems Analysis, Systemic Rotation Period, Nonlinear Programming

iForest 11 (1): 171-180 (2018) - doi: 10.3832/ifor2416-010
https://iforest.sisef.org/contents/?id=ifor2416-010

Research Articles: Determining basic forest stand characteristics using airborne laser scanning in mixed forest stands of Central Europe

Smreček R, Michnová Z, Sačkov I, Danihelová Z, Levická M, Tuček J — 2018-02-19

Smreček R, Michnová Z, Sačkov I, Danihelová Z, Levická M, Tuček J

DETERMINING BASIC FOREST STAND CHARACTERISTICS USING AIRBORNE LASER SCANNING IN MIXED FOREST STANDS OF CENTRAL EUROPE

Abstract: This study focused on the derivation of basic stand characteristics from airborne laser scanning (ALS) data, aiming to elucidate which characteristics (mean height and diameter, dominant height and diameter) are best approximated by the variables obtained using ALS data. The height of trees of different species in four permanent plots located in the Slovak Republic was derived from the normalised digital surface model (nDSM) representing the canopy surface, using an automatic approach to identify local maxima (individual treetops). Tree identification was carried out using four different spatial resolutions of the nDSM (0.5 m, 1.0 m, 1.5 m, and 2.0 m) and the number of trees identified was compared with reference data obtained from field measurements. The highest percentage of tree detection (69-75%) was observed at the spatial resolutions of 1.0 and 1.5 m. Absolute differences of tree height between reference and ALS datasets ranged from 0 to 36% at all spatial resolutions. The smallest difference in mean height was obtained using the higher spatial resolution (0.5 m), while the smallest difference in the dominant height of the relative number of thickest trees (h10% and h20%) was observed using the lower spatial resolution (2 m). The same trends also apply to diameters. The average errors at resolution of 1.0 and 1.5 m was 8.7%, 5.9% and 9.7% for mean height, h20% and h10%, respectively. ALS-derived diameters (obtained using regression models from reference data and ALS-derived individual height as predictor) showed absolute errors in the range 0-48% at all spatial resolutions. The deviation in mean diameter at a resolution of 0.5 m ranged from -12.1% to 15.3%.

Keywords: Forestry, Airborne Laser Scanning, Mixed Forest, Height of Forest Stand, Diameter of Forest Stand

iForest 11 (1): 181-188 (2018) - doi: 10.3832/ifor2520-010
https://iforest.sisef.org/contents/?id=ifor2520-010

Review Papers: Revisiting the Heat Field Deformation (HFD) method for measuring sap flow

Nadezhdina N — 2018-02-07

Nadezhdina N

REVISITING THE HEAT FIELD DEFORMATION (HFD) METHOD FOR MEASURING SAP FLOW

Abstract: The Heat Field Deformation (HFD) technique is a thermodynamic method for measuring sap flow. Based on continuous heating the HFD method allows for high time resolution measurements which are highly important when studying plant responses to abrupt environmental changes. This work provides a succinct review of previously described features of the HFD methodology. Analyzing symmetrical and asymmetrical temperature differences around a measured linear heater (dTsym and dTas) relative to their ratio dTsym/dTas (so called a K-diagram) is at the heart of this methodology. This key concept, however, has to date only been generally described in previous works on the HFD technique. My objective here is to provide a comprehensive overview describing different types of K-diagrams, their interpretation and application for determining K-values or dTas for a zero flow condition. The K-value is a measured parameter which is particularly important for objectively characterizing heat conducting properties at the sensor insertion point under specific local measurement conditions. Correctly determining the K-value is critical for accurately calculating sap flow based on recorded temperature measurements. I have included in this review several examples demonstrating how the K-value is dependent upon changes to the environment and its important role in sap flow estimation.

Keywords: K-diagram, K/R-diagram, K-value, Sap Flow per Section, Sap Flux Density, Sensor

iForest 11 (1): 118-130 (2018) - doi: 10.3832/ifor2381-011
https://iforest.sisef.org/contents/?id=ifor2381-011

Research Articles: Kinetic analysis of poplar wood properties by thermal modification in conventional oven

Marcon B, Goli G, Matsuo-Ueda M, Denaud L, Umemura K, Gril J, Kawai S — 2018-02-07

Marcon B, Goli G, Matsuo-Ueda M, Denaud L, Umemura K, Gril J, Kawai S

KINETIC ANALYSIS OF POPLAR WOOD PROPERTIES BY THERMAL MODIFICATION IN CONVENTIONAL OVEN

Abstract: The kinetics of several poplar (Populus alba L.) wood properties during thermal modification conducted in conventional oven with air recirculation were analysed and modelled in this paper. A wide range of properties was assessed, such as: equilibrium moisture content, sorption diagram, shrinkage coefficients, specific shrinkage coefficients, mass loss, modulus of elasticity, strength and colour. The tests were executed at different temperatures ranging from 90 °C to 180 °C and with different durations. The time-temperature equivalency was checked and property modifications over time analysed through master curves in order to obtain a general model connecting together properties, treatment temperature and duration. Different activation energies arising from each property evolution with treatment temperature and duration are provided showing that every modification could occur with different kinetics.

Keywords: Poplar Wood Modification, Heat Treatment, Time-temperature Equivalency, Energy of Activation, Kinetic Analysis, Mechanical Properties, Hygroscopicity, Wood Colour

iForest 11 (1): 131-139 (2018) - doi: 10.3832/ifor2422-010
https://iforest.sisef.org/contents/?id=ifor2422-010

Research Articles: Microclimate regulating functions of urban forests in Changchun City (north-east China) and their associations with different factors

Wang W, Wang H, Xiao L, He X, Zhou W, Wang Q, Wei C — 2018-02-07

Wang W, Wang H, Xiao L, He X, Zhou W, Wang Q, Wei C

MICROCLIMATE REGULATING FUNCTIONS OF URBAN FORESTS IN CHANGCHUN CITY (NORTH-EAST CHINA) AND THEIR ASSOCIATIONS WITH DIFFERENT FACTORS

Abstract: Microclimate regulating functions of urban trees and their associations with environmental factors and tree-growth characteristics are important for management and ecological evaluations. In this study, a total of 637 trees distributed in the Changchun urban region (ca. 400 km2, northeastern China) were sampled in four different types of urban forests (AF: affiliated forests; RF: roadside forests; LF: landscape and relaxation forests; EF: ecological welfare forests). Tree growth-related parameters and environmental factors (inside and outside the forest) were simultaneously measured, and location-dependent differences in shading, cooling and humidifying effects were assessed, along with their associations with the measured variables. We found that urban forests in Changchun reduced the incident sunlight by 74-86% and increased air relative humidity by 3-7%, on average. Air, soil, and upper-canopy temperatures were decreased approximately by 3 °C, <1 °C and 1 °C, respectively, showing a 3-dimensional cooling effect of urban forests on both air and soil. Shading, cooling and humidifying effects significantly differed among the four forest types, with AF stands showing the highest comprehensive scores for all the microclimate regulation functions. Regression analyses and redundancy analysis revealed that urban forests had much stronger effect in terms of microclimate regulation at sunny days with high temperature, and low air humidity. In general, stands with larger trees showed the higher regulating functions, regardless of the stand structure and composition. The results of this study may help urban forest management and planning aimed at maximizing their ecological services.

Keywords: Urban Forest Types, Shading Effect, Cooling Effect, Humidifying Effect

iForest 11 (1): 140-147 (2018) - doi: 10.3832/ifor2466-010
https://iforest.sisef.org/contents/?id=ifor2466-010

Research Articles: Estimating machine impact on strip roads via close-range photogrammetry and soil parameters: a case study in central Italy

2018-02-07

Cambi M, Giannetti F, Bottalico F, Travaglini D, Nordfjell T, Chirici G, Marchi E

ESTIMATING MACHINE IMPACT ON STRIP ROADS VIA CLOSE-RANGE PHOTOGRAMMETRY AND SOIL PARAMETERS: A CASE STUDY IN CENTRAL ITALY

Abstract: Several studies have been carried out to investigate soil compaction and rutting after logging vehicle traffic, based on time consuming and punctual field measurements. The objective of this study was to measure soil disturbances with two methods: (i) a new, image-based models derived by a structure-from-motion (SfM) photogrammetry approach; and (ii) a traditional soil sampling (bulk density and shear strength). Two trails were selected in a logging area (central Italy), one trafficked by a forwarder (FT) and one trafficked by a skidder (ST). Data collection was conducted before, during and after timber extraction. Image-based models derived by SfM photogrammetry was used to highlight the differences in the shape and distribution of the disturbances along ST and FT. Results showed that the physical parameters of soil significantly changed due to both FT and ST traffic. Machine passes increased bulk density (111% and 31% for FT and ST, respectively), penetration resistance (29% and 24% for FT and ST, respectively) and shear resistance (14% and 6% for FT and ST, respectively), whereas porosity decreased (46% and 9% for FT and ST, respectively). Significant differences between FT and ST were found when comparing ruts removal and bulges with SfM photogrammetry. After logging, FT clearly showed ruts and bulges, whereas in ST ruts and bulges were not visible, but soil displacement in the direction of extraction was evident and measurable. Nevertheless, although our result shows a larger soil disturbance caused by forwarders than skidders, it is not possible to draw any general conclusions about differences between the two machines. Data about the machine passes, or the wood volumes transported over each trial area were not available; therefore, any general conclusion is misleading. SfM photogrammetry give information not available via traditional methods, thus improving impact assessment.

Keywords: Forest Operation, Soil Impacts, Soil Displacement, Close Range Photogrammetry, Digital Terrain Model

iForest 11 (1): 148-154 (2018) - doi: 10.3832/ifor2590-010
https://iforest.sisef.org/contents/?id=ifor2590-010

Research Articles: Energy and environmental profile comparison of TMT production from two different companies - a Spanish/Portuguese case study

Ferreira J, Herrera R, Labidi J, Esteves B, Domingos I — 2018-02-07

Ferreira J, Herrera R, Labidi J, Esteves B, Domingos I

ENERGY AND ENVIRONMENTAL PROFILE COMPARISON OF TMT PRODUCTION FROM TWO DIFFERENT COMPANIES - A SPANISH/PORTUGUESE CASE STUDY

Abstract: Life Cycle Assessment (LCA) is a technique for assessing the environmental aspects and potential impacts associated with a product and has been increasingly used to identify processes or stages in the wood chain with a high environmental impact or to highlight areas where environmental information is unknown. The main aim of this study was to quantify and compare the environmental impacts and the energy used for the production of one cubic meter of Thermally Modified Timber (TMT) by two different companies, one in Spain and the other in Portugal, using the LCA methodology. The LCA study was developed based on ISO 14040/44 standards. The inventory analysis and, subsequently, the impact analysis were performed using the LCA software SimaPro8.1.0.60. The method chosen for the environmental impact assessment was ReCiPe, and for energy use the Cumulative Energy Demand method was chosen. The results show that to produce 1 m3 of thermally modified pine timber the Portuguese company used 14.38 GJ of cumulative energy demand, of which 1.92 GJ was nonrenewable and 12.46 GJ renewable, and the Spanish company used a total of 17.55 GJ, of which 2.52 GJ was nonrenewable and 15.03 GJ renewable. The thermally modified pine timber produced by the Spanish company presented the best environmental results for 13 impact categories in comparison to the 5 best environmental results presented by the Portuguese company. From the weighting triangle, we can conclude that the Portuguese pine boards have a lower environmental impact than Spanish pine boards if a high weight (> 40%) is given to resources, while a weight of <80% is given to human health; otherwise the opposite is true. Regardless of the company, the energy used in the thermal treatment process was identified as the main factor responsible for climate change, acidification, eutrophication, photochemical oxidant formation, metal depletion and fossil depletion. This has to be expected as the treatment is based on heat production and no chemicals are added during the heat treatment process. The round wood production was identified as the leading process responsible for ozone depletion and also presented remarkable contributions to eutrophication and photochemical oxidant formation.

Keywords: Energy, Life Cycle Assessment, Thermally Treated Timber

iForest 11 (1): 155-161 (2018) - doi: 10.3832/ifor2339-010
https://iforest.sisef.org/contents/?id=ifor2339-010

Review Papers: Forest functions and space: a geohistorical perspective of European forests

Pilli R, Pase A — 2018-01-31

Pilli R, Pase A

FOREST FUNCTIONS AND SPACE: A GEOHISTORICAL PERSPECTIVE OF EUROPEAN FORESTS

Abstract: The history of man has been linked to the history of wood since prehistoric times and because the forest is the main place where this resource is available, forest spaces are also directly linked to the evolution of human society. The objective of this paper is to analyze the historical evolution of the functions assigned by humans to forests, highlighting how they affect the production of space from a diachronic perspective. Focusing our attention on some European countries, we highlight that although historically, wood production was the most important function provided by wooded lands, other functions were also attributed to forests. The awareness of these functions emerged when an overexploitation of forest resources produced a lack of a specific service. When these services corresponded to a societal demand, they produced welfare benefits for the society, which were recognized as forest functions. Thus even the functions evolved in time according to the evolution of societal needs. Evaluating when and how each societal demand emerged, and consequently the moment each function was recognized, is an essential prerequisite even for a more accurate interpretation of current forest management practices. Not only is the temporal dimension of forest functions relevant, so is the spatial scale, which may differ considerably between them, ranging from the specific forest area and its owner for the productive function; to the catchment area and its inhabitants for the protective function; to a potentially larger area for the cultural and biodiversity function; and to the entire globe for the carbon-retention function. The strict, and sometimes competing, interactions between these functions may also be recognized in the production of space, which evolved in time according to the evolution of the corresponding societal needs. A forest parcel assigned to a productive function is a material space, marked in the field by colored signs, but it may also be virtually represented by a forest model or be part of some protected area. But this picture would change if, instead of looking at the present, we consider the past and the different sensations and representations concerned with forests. These complex interactions, between different functions and spatial dimensions, justify the need to balance a segregative management system with a wider, multi-functional integrated approach. What has emerged from our study is that to reach this difficult equilibrium, it is useful to consider the production processes of these forest spaces. Through this analytical approach, we can understand the interactions occurring over time between the evolution of the demands expressed by society and the main changes occurred on the forest landscape.

Keywords: Forest Functions, Services, Production of Space, History, Sustainable Forest Management

iForest 11 (1): 79-89 (2018) - doi: 10.3832/ifor2316-010
https://iforest.sisef.org/contents/?id=ifor2316-010

Research Articles: Leaf morphology of progenies in Q. suber, Q. ilex, and their hybrids using multivariate and geometric morphometric analysis

López De Heredia U, Duro-García MJ, Soto A — 2018-01-31

López De Heredia U, Duro-García MJ, Soto A

LEAF MORPHOLOGY OF PROGENIES IN Q. SUBER, Q. ILEX, AND THEIR HYBRIDS USING MULTIVARIATE AND GEOMETRIC MORPHOMETRIC ANALYSIS

Abstract: The genus Quercus is known for the occurrence of frequent hybridization events between species. Although this phenomenon is not common among holm oak (Q. ilex) and cork oak (Q. suber), these species can hybridize when they coexist in mixed stands. The result of hybridization is a viable hybrid progeny with very heterogeneous leaf morphology. Literature concerning the leaf morphology of suber-ilex hybrid seedlings is scarce, and non-existent from a quantitative point of view. In the case of the leaf morphology of hybrids and their progeny, it has been observed a high frequency of leaves with fluctuating asymmetry or developmental abnormalities, which can have a marked effect on fitness. In this work, we have characterized seedlings’ leaf morphology corresponding to two- and four-year-old half-sib progenies of holm oak, cork oak and their hybrids. For this purpose, three to ten leaves of each individual were collected, and two methodologies were used for analysis. Firstly, we used a classic morphological analysis of twelve variables that were reduced using multivariate techniques. On the other hand, shape of the leaves was thoroughly analyzed by geometric morphometric analysis methods. The extent of fluctuating asymmetry and the presence of developmental abnormalities of seedlings were analyzed calculating an asymmetry index. The results indicate that thickness is the most discriminating trait between species, and that the hybrid progenies do not show a third different phenotype compared to the parental species. However, half-siblings tend to show similar leaf morphology between them, depending on the genetic adscription of the parents. While fluctuating asymmetry was found in half-sib progenies of the parental species and the hybrids, a significant proportion of hybrid half-sibs showed strong leaf asymmetry, probably due to modifications of the epigenetic systems that control leaf development at the shoot apical meristems and leaf primordia.

Keywords: Hybridization, Fluctuating Asymmetry, Leaf Morphology, Procrustes Analysis

iForest 11 (1): 90-98 (2018) - doi: 10.3832/ifor2577-010
https://iforest.sisef.org/contents/?id=ifor2577-010

Research Articles: SimHyb: a simulation software for the study of the evolution of hybridizing populations. Application to Quercus ilex and Q. suber suggests hybridization could be underestimated

Soto A, Rodríguez-Martínez D, López De Heredia U — 2018-01-31

Soto A, Rodríguez-Martínez D, López De Heredia U

SIMHYB: A SIMULATION SOFTWARE FOR THE STUDY OF THE EVOLUTION OF HYBRIDIZING POPULATIONS. APPLICATION TO QUERCUS ILEX AND Q. SUBER SUGGESTS HYBRIDIZATION COULD BE UNDERESTIMATED

Abstract: We present SimHyb, a Java-based software for the simulation of mixed hybridizing populations. The software incorporates user-defined initial parameters and input files to account for the initial census size of two species in a closed population, the number of intermediate specific classes, the directional fertility among specific classes, the fitness coefficients for each specific class, the inheritance of fitness, and the degree of ageing and self-incompatibility of the individuals. All these demographic and adaptive parameters can be modified by the user to analyze their effect on the evolution of the mixed population. SimHyb allows the traceability of each individual, whose pedigree is also recorded. For each simulated generation the software yields an output file that is easily convertible to an input for Structure, one of the most popular softwares for the Bayesian analysis of populations. Application of SimHyb to simulate Quercus ilex and Q. suber hybridizing populations, and further analysis with Structure, reveals that advanced introgressed individuals are very often misclassified with the currently available set of nuclear microsatellite markers, so that introgression between these two species could have been underestimated in previous studies. However, we provide a simple parameter based on Structure results to identify the directionality of pollination in the progeny of a known mother tree.

Keywords: Hybridization, Introgression, Simulations, Molecular Markers, Quercus suber, Quercus ilex

iForest 11 (1): 99-103 (2018) - doi: 10.3832/ifor2569-011
https://iforest.sisef.org/contents/?id=ifor2569-011

Research Articles: Genetic diversity of core vs. peripheral Norway spruce native populations at a local scale in Slovenia

Westergren M, Bozic G, Kraigher H — 2018-01-31

Westergren M, Bozic G, Kraigher H

GENETIC DIVERSITY OF CORE VS. PERIPHERAL NORWAY SPRUCE NATIVE POPULATIONS AT A LOCAL SCALE IN SLOVENIA

Abstract: We investigated the levels of genetic diversity and population differentiation among core and peripheral populations of Norway spruce along an altitudinal gradient (from inversions to upper tree line) using isoenzymes (ISO) and nuclear simple-sequence repeats (SSR) markers on overlapping set of populations. Twenty-seven to seventy trees from 11 and 7 populations were genotyped with isoenzymes and SSRs, respectively. The results partially conform to the expectations of the central-peripheral hypothesis (CPH) and are consistent for both marker sets. Genetic differentiation among peripheral populations was low but significantly different from zero (FST-ISO = 0.013, FST-SSR = 0.009) and higher than that among core populations (FST-ISO = 0.007, FST-SSR = 0.005), conforming to central peripheral hypothesis. Contrastingly, levels of genetic diversity assessed by both richness and equitability measures did not significantly differ between peripheral and core populations (AR-ISO = 2.20 vs. 2.14, AR-SSR = 17.16 vs. 17.68, HE-ISO = 0.183 vs. 0.185, and HE-SSR = 0.935 vs. 0.935 for peripheral and core populations, respectively).

Keywords: Central Peripheral Hypothesis, Picea abies (L.) Karst., Genetic Diversity, Genetic Differentiation, Upper Tree Line, Inversion

iForest 11 (1): 104-110 (2018) - doi: 10.3832/ifor2444-011
https://iforest.sisef.org/contents/?id=ifor2444-011

Research Articles: Feasibility study of near infrared spectroscopy to detect yellow stain on cork granulate

Pérez-Terrazas D, González-Adrados JR, Sánchez-González M — 2018-01-31

Pérez-Terrazas D, González-Adrados JR, Sánchez-González M

FEASIBILITY STUDY OF NEAR INFRARED SPECTROSCOPY TO DETECT YELLOW STAIN ON CORK GRANULATE

Abstract: The aim of this study was to evaluate the viability of near infrared spectroscopy (NIRS) to detect the anomaly known as yellow stain on cork granulate. Detecting this anomaly is crucial to the cork granulate stopper industry, since it is associated with the presence of 2.4,6-Trichloroanisole (TCA), this compound having been identified as the main agent responsible for cork off-flavours. Samples for the NIRS spectra were prepared by mixing in different proportions cork granulate with high visual quality and cork granulate with yellow stain, obtaining 120 samples with 8 different percentages of yellow stain (0, 5, 10, 15, 25, 35, 50 and 100%). Two spectra per sample were collected using a Bruker MPA spectrophotometer and the partial least squares (PLS) method was used to obtain numerous equations. The best equation was obtained by utilizing the standard normal variate (SNV) spectral preprocessing, making use of only one specific part of the near infrared spectral range: 9400-4250 cm-1. This equation shows a coefficient of determination (R²) of 99.42%, a root mean square error of cross validation (RMSECV) of 2.34%, and a residual prediction deviation (RPD) of 13.10. The critical level and the limit of detection are 3.8% and 7.6%, respectively. The calculated receiver operating characteristic (ROC) curves show great discrimination capacity and the area under the ROC curve (AUC) is higher than 0.93 in any case. This study demonstrates that NIRS provides a viable technique for detecting yellow stain in cork granulate.

Keywords: Cork, Granulate, Yellow Stain, 2, 4, 6-Trichloroanisole, TCA, Near Infrared Spectroscopy, NIRS

iForest 11 (1): 111-117 (2018) - doi: 10.3832/ifor2563-010
https://iforest.sisef.org/contents/?id=ifor2563-010

Review Papers: Soil seed banks of pioneer tree species in European temperate forests: a review

Tiebel K, Huth F, Wagner S — 2018-01-25

Tiebel K, Huth F, Wagner S

SOIL SEED BANKS OF PIONEER TREE SPECIES IN EUROPEAN TEMPERATE FORESTS: A REVIEW

Abstract: The ability of short-lived tree species such as birch, alder, willow, poplar and rowan to form even a short-term soil seed bank is discussed controversially in the literature. Soil seed banks are an important component of succession and regeneration in ecosystems. Following disturbance, buried viable seeds germinate and the seedlings that establish cover the disturbed, exposed soil surfaces. The objective of this study was to undertake a literature review of soil seed bank research carried out in central and north-west European temperate forests to provide an overview of the ability of pioneer tree species to form a viable seed bank. The review of 33 publications revealed that birch is the only pioneer tree species of temperate forests with longer-lived seeds, persisting in the soil for 1 - 5 years. Birch seeds remain viable in deeper soil layers (5 - 10 cm), so birch may be assigned to the short-term persistent soil seed bank type. The seeds of alder, willow and poplar would appear to be short-lived. Maximum seed densities of all tree species were found in the upper soil layers. With increasing soil depth, seed density declined. Viable seeds of rowan were not detected in any of the soil seed bank studies, although seed trees were present. We found that in spite of the capacity for long seed dispersal distances, high densities of birch, alder and willow seeds were only observed in close proximity to seed trees. The higher the numbers of seed trees, the higher the seed densities in soils. Maximum seed densities were recorded during and shortly after seed rains had occurred. Our results reveal that a birch seed bank may compensate for years with lower levels of seed production. However, as the seed bank is only short-term persistent, it must be supplemented by fresh seeds from surrounding seed trees as often as possible to guarantee a continuous capacity for regeneration.

Keywords: Betula, Buried Seeds, Propagule Bank, Seed Density, Viable Seeds, Germination

iForest 11 (1): 48-57 (2018) - doi: 10.3832/ifor2400-011
https://iforest.sisef.org/contents/?id=ifor2400-011

Research Articles: Bird composition and diversity in oak stands under variable coppice management in Northwestern Turkey

2018-01-25

Beskardes V, Keten A, Kumbasli M, Pekin B, Yilmaz E, Makineci E, Ozdemir E, Zengin H

BIRD COMPOSITION AND DIVERSITY IN OAK STANDS UNDER VARIABLE COPPICE MANAGEMENT IN NORTHWESTERN TURKEY

Abstract: Coppice management results in profound differences in forest structure and composition, which in turn can modify habitat value for bird species. We measured bird species richness and composition at 50 sample plots in pure oak forest stands in northwestern Turkey, which differed in age, cover and height in association with coppice management. We recorded a total of 38 bird species and 699 individuals across all stands. Regression-based multimodel inference showed that structural features of forest stands strongly affect bird diversity and abundance. While canopy cover and tree height affect bird diversity positively, elevation of sampling plots, tree density and tree diameter at breast height (DBH) had a negative effect. In addition, constrained ordination analyses revealed that canopy cover was the most important factor influencing bird species composition. Forest stands that have 42-85% canopy cover, i.e., a few (2009-2580 oak trees) large tall (13.36-15.78 m) trees, were the most preferred habitat by bird species. However, we also found that different bird species favor different stand structural features. Thus, variation in stand structure from maintaining some coppice management across the landscape may be beneficial for rare or endangered species and result in greater landscape level biodiversity.

Keywords: Avian Fauna, Canopy Height, Vegetation Seral Stage, Canopy Cover, Multi-model Inference, Thrace

iForest 11 (1): 58-63 (2018) - doi: 10.3832/ifor2489-010
https://iforest.sisef.org/contents/?id=ifor2489-010

Research Articles: Windstorm disturbance triggers multiple species invasion in an urban Mediterranean forest

2018-01-25

Bonanomi G, Incerti G, Abd El-Gawad AM, Sarker TC, Stinca A, Motti R, Cesarano G, Teobaldelli M, Saulino L, Cona F, Chirico GB, Mazzoleni S, Saracino A

WINDSTORM DISTURBANCE TRIGGERS MULTIPLE SPECIES INVASION IN AN URBAN MEDITERRANEAN FOREST

Abstract: Plant invasion in forest ecosystems is a serious ecological and economic issue, deserving attention by researchers, managers and policy-makers worldwide. Many invasive plants have been reported as early successional species able to colonize disturbed areas following abrupt changes in microhabitat and resource availability. We investigated disturbance effects of a severe windstorm generated by a wet microburst (hail and rain at 160 mm h-1) remarkably affecting the canopy cover of an old-growth Quercus ilex urban forest in Southern Italy. This stand-replacing disturbance produced a mosaic of 103 gaps, 5.6 to 1632 m2 in size, over an area of 1.53 ha, uprooting 76% of the trees and decreasing thereby 85% of the standing above-ground dry biomass into the gaps. By intensive monitoring we compared above- and below-ground microclimate, soil moisture and mineral N availability in paired disturbed and control areas of the study forest. Within newly formed gaps we observed a seasonally consistent 70% higher content of nitrate nitrogen, 29% and 47% decreases of ammonia nitrogen in summer and autumn, respectively, and a higher moisture in topsoil, in addition to different above- and below-ground microclimatic conditions, with canopy cover mitigating extreme temperatures. One year after the windstorm, the microhabitat shift promoted the establishment in gaps of 15 native and 10 alien taxa previously absent in both disturbed and control plots. In such conditions, the rarefaction of the dominant Q. ilex canopy cover and the occurrence of empty niches prone to invasion could dramatically affect the local community structure and diversity. Our data indicate that stand-replacing windstorm can transiently transform the studied urban evergreen forest to an early allogenic successional community dominated, in the medium and large gaps, by annual and perennial non-native species. This is particularly relevant under a perspective of possible increasing frequency of windstorm events in the Mediterranean region in the near future.

Keywords: Invasive Plants, Microburst, Mediterranean Evergreen Woodland, Quercus ilex, Resources Fluctuation, Empty Niche

iForest 11 (1): 64-71 (2018) - doi: 10.3832/ifor2374-010
https://iforest.sisef.org/contents/?id=ifor2374-010

Research Articles: Analysis of growth of recruits of natural regeneration of Sorbus torminalis (L.) Crantz - a rare European forest tree species

Bednorz L, Nowinska R — 2018-01-25

Bednorz L, Nowinska R

ANALYSIS OF GROWTH OF RECRUITS OF NATURAL REGENERATION OF SORBUS TORMINALIS (L.) CRANTZ - A RARE EUROPEAN FOREST TREE SPECIES

Abstract: We compared growth and survival of wild service tree (Sorbus torminalis [L.] Crantz) recruits of different origin (generative: seedlings; vegetative: root suckers) established in a fenced plot at the Forest District of Krzyz (north-western Poland). Total height, annual growth of the dominant shoot, stem diameter at root collar, number of first-order branches, and mortality were measured every year over the period 2011-2015 (5 years). In 2011, a total of 382 multi-age recruits originated both from seeds (212) and root suckers (170) were recorded. Five-year mortality was higher in the generative progeny (12.3% - only youngest seedlings) as compared with vegetative recruits (2.9%). The growth rate of individuals markedly increased with height as absolute values, but slightly decreased in terms of relative growth. Statistical analysis revealed that the effect of the recruit origin on growth was noticeably weaker than that of age, defined in terms of development (height) classes. The origin of recruits had a major effect on the annual growth of the dominant shoots and a minor (though significant) effect on stem diameter and the number of first-order branches. Overall, the analysis of growth rate showed that generative recruits grow faster than the vegetative ones. Our results highlight the importance of stimulating the generative regeneration and protecting seedlings as a conservation strategy for Sorbus torminalis.

Keywords: Sorbus torminalis, Regeneration, Growth, Mortality, Seedlings, Root Suckers

iForest 11 (1): 72-78 (2018) - doi: 10.3832/ifor2347-010
https://iforest.sisef.org/contents/?id=ifor2347-010

Research Articles: Voluntary carbon credits from improved forest management: policy guidelines and case study

Vacchiano G, Berretti R, Romano R, Motta R — 2018-01-09

Vacchiano G, Berretti R, Romano R, Motta R

VOLUNTARY CARBON CREDITS FROM IMPROVED FOREST MANAGEMENT: POLICY GUIDELINES AND CASE STUDY

Abstract: Human activities have the potential to enhance carbon sequestration by the world’s forests and contribute to climate change mitigation. Voluntary carbon trading is currently the only option to pursue and reward carbon sequestration by forestry activities. Carbon credits for enhanced sequestration can be sold to partners wishing to offset their own emissions. Here we illustrate the steps taken to design guidelines for the generation of voluntary carbon credits by improved forest management in Piemonte, Italy. The guidelines have been developed in a joint effort by academia, regional administrations, forest owners and professional consultants. In particular, we show how to compute the baseline and the additionality of credit-generating forest management activities, and how to reconcile the generation of forest carbon credits with law requirements, technical limitations, and the provision of other ecosystem services. To illustrate the profitability of carbon credit generation, we simulated the application of carbon credit guidelines to two forest-rich mountain watersheds in the southern part of the Piemonte region. The two dominating tree species are beech (Fagus sylvatica L.) and chestnut (Castanea sativa Mill.). We computed current forest carbon stock and carbon credits generated in 20 years under business as usual and an alternative biomass retention scenario. The IFM resulted in an avoided harvest of 39.362 m3 for a net total of 64.014 MgCO2e after subtracting harvest emissions, or 38 Mg ha-1 throughout the permanence period of 20 years. These steps can be replicated in other mountain regions where there is interest in promoting this ecosystem service as an alternative or an addition to production-oriented forest management.

Keywords: Carbon Stocks, Carbon Credits, Biomass, Coppice, Ecosystem Services, Forest Management Plan, Climate Change Mitigation, Retention Forestry

iForest 11 (1): 1-10 (2018) - doi: 10.3832/ifor2431-010
https://iforest.sisef.org/contents/?id=ifor2431-010

Research Articles: Comparison of traits of non-colonized and colonized decaying logs by vascular plant species

Chmura D, Zarnowiec J, Staniaszek-Kik M — 2018-01-09

Chmura D, Zarnowiec J, Staniaszek-Kik M

COMPARISON OF TRAITS OF NON-COLONIZED AND COLONIZED DECAYING LOGS BY VASCULAR PLANT SPECIES

Abstract: The main goal of this study was to check whether the process of the colonization of coarse woody debris (CWD) is random or is determined by the wood traits and the environment. The study was conducted in the Karkonosze Mts., a part of Sudeten Mts. (Poland). We recorded the CWD traits and site conditions for 453 logs of spruce (Picea abies) and beech (Fagus sylvatica), which were either colonized or not colonized by vascular plants. Principal Components Analysis (PCA), a statistical comparison of two categories of logs using the Wilcoxon’s sum rank test and Generalized Linear Model (GLM) were applied. P. abies logs were colonized significantly more frequently than F. sylvatica logs. PCA demonstrated that the groups of colonized and non-colonized logs significantly differed overall in both species. The colonization status of a given log was significantly associated with CWD traits and site conditions. Decomposition class, the log diameter and the cover of bryophytes in F. sylvatica and P. abies, as well as altitude in the latter species, were significant factors that increased the probability of dead wood colonization by vascular plants. The results supported the hypothesis that vascular plants do not colonize all of the available logs and that the process of establishment is not random.

Keywords: Dead Wood, Fallen Trees, Succession, Norway Spruce, Beechwood, Montane Forest

iForest 11 (1): 11-16 (2018) - doi: 10.3832/ifor2107-010
https://iforest.sisef.org/contents/?id=ifor2107-010

Research Articles: Seasonal development of lesions caused by Hymenoscyphus fraxineus on young Fraxinus excelsior trees in Latvia

Matisone I, Matisons R, Kenigsvalde K, Gaitnieks T, Burneviča N — 2018-01-09

Matisone I, Matisons R, Kenigsvalde K, Gaitnieks T, Burneviča N

SEASONAL DEVELOPMENT OF LESIONS CAUSED BY HYMENOSCYPHUS FRAXINEUS ON YOUNG FRAXINUS EXCELSIOR TREES IN LATVIA

Abstract: The spread of the ascomycete Hymenoscyphus fraxineus, causing dieback of common ash (Fraxinus excelsior) in Europe, is rapid and the damage is pronounced, as young ashes can perish over the course of only a few months following infection. The objective of this study was to investigate the rate and extent of lesion formation on young (5-8-year-old) ashes during a vegetation season in the hemiboreal zone in Latvia. Continuous surveys (with monthly intervals) of the health condition of 30 young ash and measurements of lesion area in three stands were performed during the vegetation season of 2015. From June to September of that year, the number of observed lesions gradually rose from 58 to 87. New lesions emerged on branches (55%, 0.5 per tree), top shoots (28%, 0.3 per tree), and stems (17%, 0.2 per tree), mostly appearing at the beginning of the observation period (45%, 52%, and 3% in June, July, and August, respectively). During the vegetation season, 20% of the existing and 28% of the newly-emerged lesions on branches, as well as 20% and 25% of top shoot lesions, respectively, reached the main stem. Some (< 20% of cases) transitions of lesions from the tops and branches to the stems were observed. The extension of lesions was significant until August, and ceased afterwards in a similar fashion in all stands. The mean extension of area significantly differed between the previously-existing and newly-emerged lesions. During the vegetation season, the new lesions expanded by 25.1 ± 4.8 cm2, whereas the existing ones grew by only 7.3 ± 1.1 cm2. The extension of the new lesions varied according to their location on a tree. The spread of emerging lesions on stems was considerably slower than on branches or top shoots (1.9 ± 0.7, 7.3 ± 1.5, and 14.5 ± 4.1 cm2 per lesion per month, respectively). During the studied vegetation season (summer), the overall health score of trees decreased twice, yet the relationship between heath status and development of lesions lacked significance.

Keywords: Common Ash, Ash Dieback, Lesion Length, Sapling Wilting

iForest 11 (1): 17-23 (2018) - doi: 10.3832/ifor2283-010
https://iforest.sisef.org/contents/?id=ifor2283-010

Research Articles: Adaptive variation in physiological traits of beech provenances in Central Europe

2018-01-09

Kučerová J, Konôpková A, Pšidová E, Kurjak D, Jamnická G, Slugenová K, Gömöry D, Ditmarová L

ADAPTIVE VARIATION IN PHYSIOLOGICAL TRAITS OF BEECH PROVENANCES IN CENTRAL EUROPE

Abstract: Current climate changes can led to a decline of local beech populations fully adapted to previous climate conditions. In this context, the issue of variation in adaptive traits becomes important. A field experiment with 18-year-old trees of Fagus sylvatica L. was conducted on provenance plot located in Tále (Central Slovakia), where physiological responses of five beech provenances originating from contrasting sites along an altitudinal gradient from 55 to 1100 m a.s.l. across the range of the natural beech distribution were studied. Stomatal characteristics, parameters of chlorophyll a fluorescence and gas exchange parameters were determined. Overall, we observed a significant increase in physiological performance at the leaf level with increasing altitude of origin. Provenances from the higher altitudes showed higher CO2 assimilation rate, stomatal density, potential conductance indices and photochemical efficiency, and lower capability for dissipation of energy by heat. A similar pattern of response was recorded in relation to the precipitation regime of sites of origin. Moreover, in the context of the temperature regime, several negative trends were observed.

Keywords: Adaptation, Provenance Trial, Fagus sylvatica L., Chlorophyll a Fluorescence, Stomatal Traits, Gas Exchange

iForest 11 (1): 24-31 (2018) - doi: 10.3832/ifor2291-010
https://iforest.sisef.org/contents/?id=ifor2291-010

Research Articles: Effects of nitrogen loading under low and high phosphorus conditions on above- and below-ground growth of hybrid larch F1 seedlings

Fujita S, Wang X, Kita K, Koike T — 2018-01-09

Fujita S, Wang X, Kita K, Koike T

EFFECTS OF NITROGEN LOADING UNDER LOW AND HIGH PHOSPHORUS CONDITIONS ON ABOVE- AND BELOW-GROUND GROWTH OF HYBRID LARCH F1 SEEDLINGS

Abstract: Under present environmental conditions, hybrid larch F1 (Larix gmelinii var. japonica × Larix kaempferi) is a promising afforestation species as it has a high growth rate and tolerance against grazing damage, disease and cold. However, the input of nitrogen (N) to forests due to the increase of anthropogenic N is causing imbalances of N compared to other nutrients, especially phosphorus (P), thus affecting the root growth of healthy seedlings. However, knowledge on how different N and P conditions affect F1 root growth is still limited. In this study, various N (3 levels) and P (no addition and addition) conditions were imposed to investigate the effect of N loading on larch F1 seedlings under different P conditions. Needle N: P ratio, aboveground growth, belowground growth as well as fine root production were measured. The results showed that needle N: P ratio was higher under low P loading, and aboveground growth of seedlings increased with N loading at both low and high P conditions. Relative fine root production was decreased by N loading. On the other hand, fine root to total dry proportion was increased by N loading at no P addition, suggesting that limited P availability could increase fine root production. Total root proportion to total dry mass was decreased by N loading at both P conditions. We concluded that N loading has different effects on above- and below-ground growth of larch F1 and its effects may also differ according to P conditions, indicating that both N and P conditions should be carefully considered when planting hybrid larch F1.

Keywords: Nitrogen Deposition, Phosphorus, Fine Root Production, N: P Ratio, Hybrid Larch F1

iForest 11 (1): 32-40 (2018) - doi: 10.3832/ifor2395-010
https://iforest.sisef.org/contents/?id=ifor2395-010

Research Articles: Predicting phenology of European beech in forest habitats

Vilhar U, De Groot M, Zust A, Skudnik M, Simončič P — 2018-01-09

Vilhar U, De Groot M, Zust A, Skudnik M, Simončič P

PREDICTING PHENOLOGY OF EUROPEAN BEECH IN FOREST HABITATS

Abstract: Reliable phenological observations are important for studying the response of trees to climate and climate change. National phenological networks were not specifically established to monitor tree phenology within forests, yet they are often used to generalise tree phenological phases at national or regional scales. Our objective was to investigate whether a phenological monitoring network using trees in open areas can accurately predict phenology of European beech (Fagus sylvatica L.) located within forests by using two models: one with correlates of environmental variables and one with interpolated monthly air temperature and sun hours. The first leaf unfolding, general leaf colouring and leaf fall dates from 2004 through 2010 were modelled using data from 47 Slovene National Phenology Network (NPN) stations in open areas and tested on phenological observations within forests using data from the UNECE CRLTAP ICP Forests network. Good agreement was found between predicted and observed first leaf unfolding in the forest, while slightly lower agreement was detected for general leaf colouring and leaf fall. Suggestions for the improvement of national phenological network are discussed in order to better predict beech phenology in forest habitats.

Keywords: Leaf Unfolding, Leaf Colouring, Leaf Fall, Modelling, Fagus sylvatica, Slovene National Phenology Network, ICP Forests

iForest 11 (1): 41-47 (2018) - doi: 10.3832/ifor1820-010
https://iforest.sisef.org/contents/?id=ifor1820-010

Research Articles: Historical and contemporary forest ecosystem changes in the Beskid Mountains (southern Poland) between 1848 and 2014

Sobala M, Rahmonov O, Myga-Piatek U — 2017-12-19

Sobala M, Rahmonov O, Myga-Piatek U

HISTORICAL AND CONTEMPORARY FOREST ECOSYSTEM CHANGES IN THE BESKID MOUNTAINS (SOUTHERN POLAND) BETWEEN 1848 AND 2014

Abstract: Landscape changes in the Carpathians are related to centuries of human activity, which can be regarded as the key component of global change. Changes in mountainous regions are mainly caused by agriculture, urbanization, forest cutting for production and land abandonment. This paper aimed to assess the impact of natural and historical-cultural factors on forest ecosystem transformations occurred in the period 1848-2014 in two small areas (about 45 km2) on the Beskid Mountains (southern Poland). The comparison of historical and current maps, along with the application of GIS and field verification, allowed a full interpretation of changes in land use in the studied areas. A decrease of 58.0% in non-forest areas was observed in the considered period, while the forested area grew systematically by 28.3% and the forest-field boundary lowered in altitude. Current forest ecosystems are distributed as a mosaic and mainly consist of Dentario glandulosae-Fagetum, Luzulo nemorosae-Fagetum, Abieti-Piceetum montanum, with logged sites taking up large areas. Forest ecosystems include valuable semi-natural meadows such as Gladiolo-Agrostietum, Hieracio-Nardetum, Arrhenatheretum medioeuropaeum, Cirsietum rivularis or Juncetum effusi, whose extension is reducing and fragmentation increasing due to the recolonization of forest tree species after abandonment. We concluded that trends in land use in the Carpathians were mainly determined by non-environmental factors related to the development of farming-pasturing and forest management. The applied approach could be extended to other regions in the Carpathians which were subject to analogous historical-cultural influences. Moreover, our results allow for a comparison with other regions which are subject to similar impacts of natural processes, but to different impact of historical and cultural processes.

Keywords: Landscape Research, Forest Transformation, Land Use Changes, Historical Maps, Poland, Beskid Mountains, Carpathians

iForest 10 (6): 939-947 (2017) - doi: 10.3832/ifor2418-010
https://iforest.sisef.org/contents/?id=ifor2418-010

Research Articles: Testing common hornbeam (Carpinus betulus L.) acetylated with the Accoya method under industrial conditions

Fodor F, Lankveld C, Németh R — 2017-12-19

Fodor F, Lankveld C, Németh R

TESTING COMMON HORNBEAM (CARPINUS BETULUS L.) ACETYLATED WITH THE ACCOYA METHOD UNDER INDUSTRIAL CONDITIONS

Abstract: Hornbeam is known for its high density, hardness, toughness, and wear resistance, but due to its low durability (Class 5 according to EN 350), limited wood quality, and rather small sawmill yield it is mainly utilized as firewood today. The potential for hornbeam to be used as solid, high-quality wood material exists if its durability and dimensional stability can be increased. Hornbeam boards were acetylated under industrial conditions and tests were carried out to evaluate the treatability of this wood species by acetylation. In this study, the examination of physical, mechanical, and durability properties of acetylated hornbeam are described and compared to untreated hornbeam and to acetylated beech, which has a similar anatomical structure to hornbeam. Acetylated hornbeam was also compared to acetylated radiata pine, which is the main product of Accsys Technologies. These comparisons include the determination of the equilibrium moisture content, density, dimensional stability, accelerated checking, color change, water uptake, decay resistance, compression strength, modulus of rupture (MOR), modulus of elasticity (MOE), impact bending strength, Janka hardness, Brinell hardness, and impact bending strength. The aim of this project is the creation of a new product thereby widening the usage of this species.

Keywords: Hornbeam, Acetylation, Accoya, Physical Properties, Mechanical Properties, Durability, Color

iForest 10 (6): 948-954 (2017) - doi: 10.3832/ifor2359-010
https://iforest.sisef.org/contents/?id=ifor2359-010

Research Articles: Patterns of genetic diversity in European beech (Fagus sylvatica L.) at the eastern margins of its distribution range

Ciocîrlan E, Sofletea N, Ducci F, Curtu AL — 2017-12-10

Ciocîrlan E, Sofletea N, Ducci F, Curtu AL

PATTERNS OF GENETIC DIVERSITY IN EUROPEAN BEECH (FAGUS SYLVATICA L.) AT THE EASTERN MARGINS OF ITS DISTRIBUTION RANGE

Abstract: Populations located at the periphery of the species’ distribution range may play an important role in the context of climate change. These peripheral populations may contain specific adaptations as a result of extreme environmental conditions. The aim of this paper was to assess within population genetic diversity and among population differentiation in one of the most important forest tree species in Europe, European beech (Fagus sylvatica), at the eastern margins of its natural range. We analysed four peripheral, isolated populations and five core populations from the continuous natural range along the Carpathian Mountains using a set of microsatellite markers. Higher levels of genetic diversity as measured by allelic richness (7.34 vs. 6.50) and observed heterozygosity (0.71 vs. 0.59) were detected in core populations than in peripheral ones. Population differentiation was slightly higher among peripheral populations than among core, Carpathian populations. There was strong evidence of bottleneck effects in two out of the four peripheral, isolated populations. Both core, Carpathian populations and peripheral, lowlands populations share the same chloroplast haplotype suggesting a common geographical origin from the putative Moravian refuge area. Past long distance founding events with material from the Carpathian mountain chain might explain the occurrence of small, isolated beech populations towards the steppe in the south-east of Romania. Our genetic data may contribute to a better understanding of the evolutionary history of the remnants of beech scattered occurrences at the eastern margins of species’ distribution range.

Keywords: Fagus sylvatica, Genetic Diversity, Peripheral Populations, Bottleneck Effect

iForest 10 (6): 916-922 (2017) - doi: 10.3832/ifor2446-010
https://iforest.sisef.org/contents/?id=ifor2446-010

Research Articles: Identifying priority conservation areas for above-ground carbon sequestration in Central Mexico

Cruz-Huerta C, González-Guillén MDJ, Martínez-Trinidad T, Escalona-Maurice M — 2017-12-07

Cruz-Huerta C, González-Guillén MDJ, Martínez-Trinidad T, Escalona-Maurice M

IDENTIFYING PRIORITY CONSERVATION AREAS FOR ABOVE-GROUND CARBON SEQUESTRATION IN CENTRAL MEXICO

Abstract: Identifying forest ecosystems with significant ecological, social, and/or economic values is an important first-step in conserving landscape function. Here, we identify priority conservation areas in the municipalities of Chignahuapan and Zacatlan, Puebla (Mexico), based on: (i) their capacity to sequester atmospheric CO2; and (ii) risk of future deforestation. We also explore management strategies for priority-lands conservation in the Mexican context. Above-ground C sequestration was estimated using wood density and biomass expansion-factor data available from local forestry sources. Deforestation risk was estimated by a probabilistic model of land use change using socioeconomic and biophysical variables. Carbon sequestration estimates ranged from 14 to 531 Mg ha-1 for Chignahuapan and Zacatlan, respectively. An estimated 11.746 and 4.406 ha of forest was determined to be at risk of deforestation in each municipality. Of these at-risk lands, 2.421 and 1.798 ha were determined to be at high risk. In combination, we determined that 10.687 and 4.319 ha, respectively, are priority lands for carbon sequestration in Chignahuapan and Zacatlan, of which 628 and 310 ha were determined to have high conservation priority. Identifying priority conservation areas through the integrated assessment of carbon sequestration and deforestation risk can enhance efforts to target land management strategies to mitigate climate change impacts. This approach can serve as a model for other forested regions in Mexico and other countries.

Keywords: Forest Carbon Sinks, REDD, Climate Change, Deforestation Risk, Priority Conservation, Probabilistic Model, Land Use, Development

iForest 10 (6): 923-929 (2017) - doi: 10.3832/ifor1980-010
https://iforest.sisef.org/contents/?id=ifor1980-010

Research Articles: Comparison of timber-house technologies and initiatives supporting use of timber in Slovenia and in Sweden - the state of the art

Kitek Kuzman M, Sandberg D — 2017-12-07

Kitek Kuzman M, Sandberg D

COMPARISON OF TIMBER-HOUSE TECHNOLOGIES AND INITIATIVES SUPPORTING USE OF TIMBER IN SLOVENIA AND IN SWEDEN - THE STATE OF THE ART

Abstract: Historically, Slovenia and Sweden have equivalent uses of timber in construction and a long tradition of timber engineering and architecture. Nevertheless, in spite of these similarities, the development path to reach a modern and industrialized use of timber in construction which allows a diversity of architectural expression and design possibilities has differed considerably between these two countries, after the function-based building regulations that were introduced in Europe nearly three decades ago. This paper gives an overview of some characteristic modern timber buildings in Slovenia and Sweden, and the different construction techniques that are used in these two countries. Successful initiatives supporting the use of timber in construction are also presented. The opportunities for the further development of sustainable timber constructions in Slovenia and Sweden lie in new production methods, high prefabrication, and energy-efficient and climate-effective architecture, besides partnership and increased responsibilities for planning, improved and systematic feedback of experience and team cooperation, as well as knowing users identity, values and life style.

Keywords: Architecture, Timber Construction, Technologies, Promotion Initiatives

iForest 10 (6): 930-938 (2017) - doi: 10.3832/ifor2397-010
https://iforest.sisef.org/contents/?id=ifor2397-010

Review Papers: Wood modification technologies - a review

Sandberg D, Kutnar A, Mantanis G — 2017-12-01

Sandberg D, Kutnar A, Mantanis G

WOOD MODIFICATION TECHNOLOGIES - A REVIEW

Abstract: The market for new durable products of modified wood has increased substantially during the last few years, especially in Europe. This increased interest depends partly on the restricted use of toxic preservatives due to increased environmental concern, as well as the need for reduced maintenance for wood products that are mainly for exterior use. Furthermore, as sustainability becomes a greater concern, the environmental impact of construction and interior materials should be included in planning by considering the entire life cycle and embodied energy of the materials used. As a result, wood modification has been implemented to improve the intrinsic properties of wood, widen the range of sawn timber applications, and acquire the form and functionality desired by engineers, without bringing environmental friendliness into question. The different wood modification processes are at various stages of development, and the challenges that must be overcome to expand to industrial applications differ amongst them. In this paper, three groups of wood modification processes are discussed and exemplified with modified wood products that have been newly introduced to the market: (i) chemical processing (acetylation, furfurylation, resin impregnation etc.); (ii) thermo-hydro processing (thermal treatment); and (iii) thermo-hydro-mechanical processing (surface densification). Building on these examples, the paper will discuss the environmental impact assessment of modification processes and further development needs.

Keywords: Chemical Treatments, Thermo-hydro-mechanical, LCA, Acetylation, Furfurylation, Resin Impregnation, Environmental Impacts, Densification

iForest 10 (6): 895-908 (2017) - doi: 10.3832/ifor2380-010
https://iforest.sisef.org/contents/?id=ifor2380-010

Research Articles: Density management diagram for teak plantations in Tabasco, Mexico

Minoche D, Risio-Allione L, Herrero De Aza C, Martínez-Zurimendi P — 2017-12-01

Minoche D, Risio-Allione L, Herrero De Aza C, Martínez-Zurimendi P

DENSITY MANAGEMENT DIAGRAM FOR TEAK PLANTATIONS IN TABASCO, MEXICO

Abstract: Density management diagrams are valuable tools for managing specific forest species. The aim of this study was to obtain a density management diagram for teak (Tectona grandis L.) plantations in the State of Tabasco in Mexico. To achieve this objective, a set of 10 plantations were studied, in which 42 plots were established. Two equations were fitted simultaneously, including one related to the quadratic mean diameter, stand density and dominant height and the other which related the total stand volume to the quadratic mean diameter, stand density and dominant height. The results showed that the diagram had an acceptable predictability, thus indicating its usefulness and accuracy in planning silvicultural interventions. This diagram is a very powerful tool that can enable stakeholders to manage teak plantations in the State of Tabasco.

Keywords: Silvicultural Interventions, Stand Density Diagram, Quadratic Mean Diameter, Tectona grandis

iForest 10 (6): 909-915 (2017) - doi: 10.3832/ifor2247-010
https://iforest.sisef.org/contents/?id=ifor2247-010

Research Articles: Density management diagrams for sweet chestnut high-forest stands in Portugal

Patrício MS, Nunes L — 2017-11-06

Patrício MS, Nunes L

DENSITY MANAGEMENT DIAGRAMS FOR SWEET CHESTNUT HIGH-FOREST STANDS IN PORTUGAL

Abstract: This study aims to develop stand density management diagrams (SDMDs) for pure even-aged high-forest stands of sweet chestnut in Portugal, defining the appropriate upper and lower limits of growing stock while considering the biological, technological and economic objectives that are expected for these stands. The SDMDs were developed with data collected from high-forest stands in northern Portugal, which is the main representative area of these stands in the country. Data were collected from 23 pure even-aged permanent plots with re-measurement intervals of 4-10 years, 43 semi-permanent plots and 18 even-aged temporary plots; all plots were established in chestnut high-forest stands with a broad range of ages. SDMDs were constructed by simultaneously fitting four nonlinear equations relating stand variables using the full information likelihood technique. SDMDs for the estimation of stand total volume, stand stem biomass, stand total aboveground biomass, and carbon content in aboveground biomass are presented as bivariate graphs with dominant height on the x-axis and the number of trees per hectare on the y-axis (using logarithmic scale). A tool is made available to define an optimal range of stand density for a silviculture oriented to single-stem selection on a tree-by-tree basis, focusing management on the most valuable trees. This tool is aimed to support forest managers in the decision-making process, enabling them to schedule thinnings on the basis of the dominant height growth of the trees with the greatest potential (frame trees), maintaining an adequate growing stock and assessing the corresponding aboveground wood volume, biomass, carbon, and mean diameter breast height.

Keywords: Castanea sativa Mill., Stand Density, Thinning, Biomass, Site Index, Dominant Height, Forest Management

iForest 10 (6): 865-870 (2017) - doi: 10.3832/ifor2411-010
https://iforest.sisef.org/contents/?id=ifor2411-010

Research Articles: Evaluating the impact of Hymenoscyphus fraxineus in Trentino (Alps, Northern Italy): first investigations

Giongo S, Oliveira Longa CM, Dal Maso E, Montecchio L, Maresi G — 2017-11-06

Giongo S, Oliveira Longa CM, Dal Maso E, Montecchio L, Maresi G

EVALUATING THE IMPACT OF HYMENOSCYPHUS FRAXINEUS IN TRENTINO (ALPS, NORTHERN ITALY): FIRST INVESTIGATIONS

Abstract: The spread of Hymenoscyphus fraxineus has been causing great concern regarding the survival of European ash (Fraxinus excelsior) throughout Europe since the 1990s. The disease was first recorded in Trentino (southern Alps, Italy) in 2012 and has spread throughout the mountain landscape, where ash trees are scattered in small and isolated stands in different valleys. The status of the disease was checked by monitoring the damage to natural regeneration and adult trees in 90 sites spread over the whole region. The survey confirmed the complete colonization by the pathogen of the whole investigated area, with high levels of damage to both young and adult ash trees. Regeneration (both seedlings and saplings) was observed to be affected by the fungus in 88 plots out of 90. Out of 4486 examined young European ashes, 2261 (50.4%) were affected and 789 (17.6%) were already dead. Ten of the 384 assayed flowering ashes (Fraxinus ornus) showed symptoms on branches and apical stems, similar to those observed for European ash. Isolation and molecular analysis proved the presence of the fungus on both symptomatic European and flowering ashes. The examined 386 adult trees showed different levels of damage, sometimes reaching more than 75% of the crown. Some individual trees (42) growing close to severely damaged trees appeared fully healthy, which suggests the possible existence of some resistant/tolerant individuals in the examined populations.

Keywords: Ash Dieback, Fraxinus excelsior, Fraxinus ornus, Natural Regeneration, Forest Management

iForest 10 (6): 871-878 (2017) - doi: 10.3832/ifor2486-010
https://iforest.sisef.org/contents/?id=ifor2486-010

Research Articles: Examining the evolution and convergence of wood modification and environmental impact assessment in research

Burnard M, Posavčević M, Kegel E — 2017-11-06

Burnard M, Posavčević M, Kegel E

EXAMINING THE EVOLUTION AND CONVERGENCE OF WOOD MODIFICATION AND ENVIRONMENTAL IMPACT ASSESSMENT IN RESEARCH

Abstract: We performed a bibliometric analysis of peer-reviewed publications on wood modification and environmental impact assessment of wood retrieved from the Scopus® database. We used data mining and network analysis tools to investigate the development of the field over time. We explore both wood modification and environmental impact assessment separately, and investigate where the publication record overlaps. Our research revealed that in recent years both topics have produced sharp increases in the number of publications, and have diversified greatly in recent years. Additionally, there were differences in the author collaboration patterns between each field. Fewer authors have contributed over a longer period of time in the wood modification publication record, whereas more authors have contributed over a shorter period of time to the environmental impact assessment of wood record, but they tend to collaborate less frequently. These methods allow researchers and industry members to quickly explore trends in research topics, the number of publications, where research is being conducted, and the growing network of researchers publishing together.

Keywords: Bibliometrics, Data Mining, Network Analysis, Wood Modification, Environmental Impact Assessment, COST Action FP1407, Wood

iForest 10 (6): 879-885 (2017) - doi: 10.3832/ifor2390-010
https://iforest.sisef.org/contents/?id=ifor2390-010

Research Articles: Assessment of timber extraction distance and skid road network in steep karst terrain

Duka A, Grigolato S, Papa I, Pentek T, Poršinsky T — 2017-11-06

Duka A, Grigolato S, Papa I, Pentek T, Poršinsky T

ASSESSMENT OF TIMBER EXTRACTION DISTANCE AND SKID ROAD NETWORK IN STEEP KARST TERRAIN

Abstract: This study aims to define a simple and effective method to calculate skidding distances on steep karst terrain, rich in ground obstacles (stoniness and rockiness) to support decision planning of secondary and primary forest infrastructure network for timber extraction in productive selective cut forests. Variations between geometrical extraction distances and actual distances were highlighted on the operational planning level (i.e., compartment level) through GIS-related calculation models, focusing on cable skidder timber extraction. Automation in defining geometrical and real extraction distances, as well as relative forest openness were achieved by geo-processing workflows in GIS environment. Due to variation of extraction correction factors at the compartment level from a minimum of 1.19 to a maximum of 5.05 in the same management unit, it can be concluded that planning harvesting operations (timber extraction) at operational level should not include the use of correction factors previously obtained for entire terrain (topographical) categories, sub-categories or even management units.

Keywords: Real Extraction Distance, Steep Terrain, Skid Road Network, GIS Environment, Karst Terrain

iForest 10 (6): 886-894 (2017) - doi: 10.3832/ifor2471-010
https://iforest.sisef.org/contents/?id=ifor2471-010

Research Articles: Understory vegetation dynamics and tree regeneration as affected by deer herbivory in temperate hardwood forests

Laurent L, Mårell A, Balandier P, Holveck H, Saïd S — 2017-10-26

Laurent L, Mårell A, Balandier P, Holveck H, Saïd S

UNDERSTORY VEGETATION DYNAMICS AND TREE REGENERATION AS AFFECTED BY DEER HERBIVORY IN TEMPERATE HARDWOOD FORESTS

Abstract: Plant competition and deer browsing are two main factors which limit tree recruitment. We examined natural tree-recruitment processes under continuous-tree-cover management. Changes in plant communities and tree regeneration were monitored over an eight-year period at two different sites in a temperate hardwood forest in the North-East of France. We used paired control plot (unfenced areas, free access to deer) and exclosures (fenced areas, excluding deer) at both sites. Shade-tolerant browsing-tolerant opportunistic species (beech, Fagus sylvatica at site 1 and bramble, Rubus spp. at site 2) were present in low numbers at the beginning of the study. We found that these species used a sit-and-wait strategy, waiting for opportunities to proliferate (thinning and deer exclusion). In the exclosure at site 1, beech proliferate slowly. In the exclosure at site 2, bramble proliferated enough during the first two growing seasons to prevent tree recruitment. Thus, fencing encouraged beech sapling or bramble growth, and this growth in turn was detrimental to the richness and diversity of the plant community. The two study cases presented show that both plant competition and deer browsing can be problematic for tree recruitment. Our results further suggest that excluding deer is not sufficient to enhance the growth of browse-sensitive and moderately shade-tolerant tree species such as oaks (Quercus petraea and Q. robur).

Keywords: Understory Vegetation, Plant Interaction, Competition, Browsing, Forest Regeneration, Exclosure

iForest 10 (5): 837-844 (2017) - doi: 10.3832/ifor2186-010
https://iforest.sisef.org/contents/?id=ifor2186-010

Research Articles: Contrasting multi-taxa diversity patterns between abandoned and non-intensively managed forests in the southern Dolomites

2017-10-26

Sitzia T, Campagnaro T, Dainese M, Cassol M, Dal Cortivo M, Gatti E, Padovan F, Sommacal M, Nascimbene J

CONTRASTING MULTI-TAXA DIVERSITY PATTERNS BETWEEN ABANDONED AND NON-INTENSIVELY MANAGED FORESTS IN THE SOUTHERN DOLOMITES

Abstract: The abandonment of silvicultural activities can lead to changes in species richness and composition of biological communities, when compared to those found in managed forests. The aim of this study was to compare the multi-taxonomical diversity of two mature silver fir-beech-spruce forests in the southern Dolomites (Italy), corresponding to the European Union habitat type 9130. The two sites share similar ecological and structural characteristics, but differ in their recent management histories. In the last 50 years, one site underwent non-intensive management, while the other was left unmanaged and was included in a forest reserve. The species richness and composition of eight taxa were surveyed in the two sites between 2009 and 2011. The difference in mean species richness between the two forest management types was tested through permutation tests, while differences in species composition were tested by principal coordinates analysis and the permutational multivariate analysis of variance. Mean species richness of soil macrofungi, deadwood lichens, bark beetles, and longhorn beetles were significantly higher in the abandoned than in the non-intensively managed forests. Deadwood fungi and epiphytic lichens did not differ in mean species richness between the two study sites, while mean species richness of ground beetles and birds were higher in the non-intensively managed than in the abandoned forest. Significant differences in species composition between the two sites were found for all the taxa, except for longhorn beetles. These results indicate that improving forest landscape heterogeneity through the creation of a mosaic of abandoned and extensively managed forests should better fulfill the requirements of ecologically different taxa.

Keywords: Asperulo-Fagetum, Forestry Abandonment, Biodiversity Conservation, Selection Cutting, Natura 2000, Silver Fir

iForest 10 (5): 845-850 (2017) - doi: 10.3832/ifor2181-010
https://iforest.sisef.org/contents/?id=ifor2181-010

Research Articles: Salinity strongly drives the survival, growth, leaf demography, and nutrient partitioning in seedlings of Xylocarpus granatum J. König

Siddique MRH, Saha S, Salekin S, Mahmood H — 2017-10-26

Siddique MRH, Saha S, Salekin S, Mahmood H

SALINITY STRONGLY DRIVES THE SURVIVAL, GROWTH, LEAF DEMOGRAPHY, AND NUTRIENT PARTITIONING IN SEEDLINGS OF XYLOCARPUS GRANATUM J. KöNIG

Abstract: Salinity is increasing in the Sundarbans (Bangladesh) due to sea-level rise and the reduction of fresh water flow. Xylocarpus granatum is one of the most valuable mangrove tree species of the Sundarbans. We conducted a six-month long study to investigate the effect of salinity on the survival, growth, leaf demography, and nutrient partitioning in parts of X. granatum seedlings. Our results showed that most of the seedlings (90%) survived at 0 to 5 PSU salinity, and this survival percentage was found to decrease at higher saline conditions. Salinity of more than 25 PSU was lethal to the plants as no seedlings survived under these conditions. In this salinity (25 PSU), accelerated leaf fall coupled with a reduction in the new leaves caused loss of leaves. The relative growth rate (RGR) was higher at 0 to 5 PSU salinity, and conversely, a lower growth rate was observed with increased salinity. Higher saline conditions created stress, which inhibited nutrient (N, P and K) accumulation in different parts (leaf, stem, bark and root) of the seedlings. We concluded that salinity is a critical factor for the growth and survival of X. granatum either by inhibiting plant nutrient uptake or due to salinity related toxicity.

Keywords: Mangroves, Climate Change, Leaf Demography, Salinity, Sundarbans, Xylocarpus granatum

iForest 10 (5): 851-856 (2017) - doi: 10.3832/ifor2382-010
https://iforest.sisef.org/contents/?id=ifor2382-010

Research Articles: Pre-treatment with sodium silicate, sodium hydroxide, ionic liquids or methacrylate resin to reduce the set-recovery and increase the hardness of surface-densified Scots pine

Neyses B, Rautkari L, Yamamoto A, Sandberg D — 2017-10-26

Neyses B, Rautkari L, Yamamoto A, Sandberg D

PRE-TREATMENT WITH SODIUM SILICATE, SODIUM HYDROXIDE, IONIC LIQUIDS OR METHACRYLATE RESIN TO REDUCE THE SET-RECOVERY AND INCREASE THE HARDNESS OF SURFACE-DENSIFIED SCOTS PINE

Abstract: The hardness of the outer regions of solid wood can be improved by surface densification, and this opens up new fields of application for low-density species. So far, surface densification relies on time- and energy-consuming batch processes, and this means that the potential advantages over more expensive hardwood species or non-renewable materials are reduced. Using fossil-based plastics or applying wood densification processes with a high energy consumption has adverse effects on the environment. In a previous study, it was shown that the surface of wood can be densified by a continuous high-speed process, adopting a roller pressing approach. The desired density profiles could be obtained at process speeds of up to 80 m min-1, but an equally simple and fast method to eliminate the moisture-induced set-recovery of the densified wood cells is still required. For this reason, the goal of the present study was to evaluate the effect on the set-recovery and hardness of surface-densified Scots pine after a fast pre-treatment with solutions of sodium silicate, sodium hydroxide, methacrylate resin, and ionic liquids. The Scots pine specimens were pre-treated by applying the chemical treatment and impregnation agents to the wood surface with a paper towel, before the specimens were densified. For each type of treatment, 15 specimens were densified in a hot press. The set-recovery was measured after two wet-dry cycles, and 30 Brinell hardness measurements were carried out on each group of specimens. In general, the effect of the treatments on the set-recovery was rather low. Ionic liquid solutions appear to work as a strong plasticiser and the treatment led to a reduction in set-recovery by 25%. The treatments with sodium silicate, ionic liquids and methacrylate resin led to a greater hardness than in untreated and densified specimens. Further experiments are needed to improve the depth of penetration of the treatment solutions into the wood surface, as this was identified as one of the main causes of the rather weak effects.

Keywords: Water Glass, Compression, Wood Modification, Surface Treatment, Ionic Liquid, Sodium Hydroxide, Methacrylate Resin, Sodium Silicate

iForest 10 (5): 857-864 (2017) - doi: 10.3832/ifor2385-010
https://iforest.sisef.org/contents/?id=ifor2385-010

Review Papers: Drought-induced oak decline in the western Mediterranean region: an overview on current evidences, mechanisms and management options to improve forest resilience

Gentilesca T, Camarero JJ, Colangelo M, Nolè A, Ripullone F — 2017-09-25

Gentilesca T, Camarero JJ, Colangelo M, Nolè A, Ripullone F

DROUGHT-INDUCED OAK DECLINE IN THE WESTERN MEDITERRANEAN REGION: AN OVERVIEW ON CURRENT EVIDENCES, MECHANISMS AND MANAGEMENT OPTIONS TO IMPROVE FOREST RESILIENCE

Abstract: Increased forest vulnerability is being reflected as more widespread and severe drought-induced decline episodes. In particular, the Mediterranean area is revealing a high susceptibility to phenomena of loss in tree vitality across species. Within tree species, oaks (Quercus spp.) are experiencing extensive decline in many countries. However, in the wake of the so-called “oak decline phenomenon”, the attention on these species has generally been limited. In this paper, we review the current available literature on oak-decline cases reported within the Mediterranean Basin, with particular remark for those occurred in Italy and Spain. More specifically our main aims were to: (i) provide an update on the patterns and mechanisms of decline by focusing on tree-ring and wood-anatomical variables; (ii) provide some hints for improving the resistance and resilience of oak stands experiencing decline. Our review reveals that drought is reported as the main driver triggering oak decline within the Mediterranean Basin, although other causes (i.e., increasing temperature, pathogens attack or excessive stand density) could exacerbate decline. In most reported cases, drought induced a substantial reduction of growth and changes in some wood anatomical properties. Indeed, growth decline prior death is also indicated as an early-warning signal of impending death. In ring-porous oak species, declining trees were often characterized by a very low production of latewood and a decrease in lumen area of the widest earlywood vessels, suggesting a potential reduction of hydraulic conductivity. Moreover, hydraulic dysfunction is reported as the main cause of decline. Finally, regarding management actions that should be considered for improving the resilience of declining stands and preserve the species-specific stand composition, it could be useful to shorten the rotation period of coppice stands or promoting their gradual conversion towards high forests, and favoring more drought-resistant species should also be considered. In addition, regeneration prior to regeneration cuts should be improved by anticipating seed dispersal or by planting oak seedlings obtained from local germoplasm.

Keywords: Growth, Adaptive Forest Management, Quercus, Resilience, Forest Dieback

iForest 10 (5): 796-806 (2017) - doi: 10.3832/ifor2317-010
https://iforest.sisef.org/contents/?id=ifor2317-010

Research Articles: Life cycle assessment of tannin extraction from spruce bark

Ding T, Bianchi S, Ganne-Chédeville C, Kilpeläinen P, Haapala A, Räty T — 2017-09-25

Ding T, Bianchi S, Ganne-Chédeville C, Kilpeläinen P, Haapala A, Räty T

LIFE CYCLE ASSESSMENT OF TANNIN EXTRACTION FROM SPRUCE BARK

Abstract: Tannins have shown antifungal effects and have been considered a potential natural compound for wood preservation. Extracts produced from softwood bark contain both tannins and non-tannin compounds, which may reduce the effectiveness of tannin used as a wood preservative. The purpose of this research is to study the environmental impact of hot water extraction, identify the hot spots within the tannin cradle-to-gate life cycle and give suggestions to optimize its environmental profile. Different extraction and post-extraction scenarios of tannin production are compared using the life-cycle assessment method. Experiments were designed to study the tannin yield under different extraction scenarios; the post-extraction scenario analysis was based on literature review. The results show that the extract drying process is the primary contributor to the environmental impact of tannin production. Both preliminary cold water extraction and ultrafiltration after extraction are beneficial as they have fewer non-tannin compounds in the final products; however, preliminary cold water extraction had a considerably lower environmental performance. Successive extractions using fresh water at each cycle increased the total tannin yield, but increased the environmental burden. Using only evaporation to obtain a desired tannin concentration is not environmentally efficient. This paper provides a quantified environmental analysis for the development of tannin-treated wood products and discusses the different tannin extraction scenarios from an environmental point of view.

Keywords: LCA, Tannin, Spruce Bark, Hot Water Extraction, Evaporation, Spray Drying, Ultrafiltration, Preservative

iForest 10 (5): 807-814 (2017) - doi: 10.3832/ifor2342-010
https://iforest.sisef.org/contents/?id=ifor2342-010

Review Papers: Comparative assessment for biogenic carbon accounting methods in carbon footprint of products: a review study for construction materials based on forest products

Tellnes LG, Ganne-Chedeville C, Dias A, Dolezal F, Hill C, Zea Escamilla E — 2017-09-25

Tellnes LG, Ganne-Chedeville C, Dias A, Dolezal F, Hill C, Zea Escamilla E

COMPARATIVE ASSESSMENT FOR BIOGENIC CARBON ACCOUNTING METHODS IN CARBON FOOTPRINT OF PRODUCTS: A REVIEW STUDY FOR CONSTRUCTION MATERIALS BASED ON FOREST PRODUCTS

Abstract: The forest and building sector is of major importance in climate change mitigation and therefore construction materials based on forest products are of great interest. While energy efficiency has had a large focus in climate change mitigation in the building sector, the carbon footprint of the construction material is gaining relevance. The carbon footprint of construction materials can vary greatly from one type to another, the building sector is consequently demanding documentation of the carbon footprint of the materials used. Using an environmental product declaration (EPD) is an objective and standardised solution for communicating the environmental impacts of construction products and especially their carbon footprint. Nevertheless, it is challenging to include the features of forest products as pools of carbon dioxide. There is currently a focus on research into methods for the accounting of sequestered atmospheric carbon dioxide and also implementation of these methods into technical standards. This paper reviews the recent research and technical standards in this field to promote a common understanding and to propose requirements for additional information to be included in EPDs of forest-based products. The main findings show the need for reporting the contribution of biogenic carbon to the total on greenhouse gas emissions and removals over the product’s lifecycle. In order to facilitate the implementation of more advanced methods from research, the EPD should also include more detailed information of the wood used, in particular species and origin.

Keywords: Climate Change, Forest Based Construction Materials, Environmental Product Declaration (EPD), Carbon Footprint, Global Warming, Delayed Emissions, Carbon Storage, Biogenic Carbon

iForest 10 (5): 815-823 (2017) - doi: 10.3832/ifor2386-010
https://iforest.sisef.org/contents/?id=ifor2386-010

Research Articles: Compositions of compounds extracted from thermo-treated wood using solvents of different polarities

Lovaglio T, D’Auria M, Rita A, Todaro L — 2017-09-25

Lovaglio T, D’Auria M, Rita A, Todaro L

COMPOSITIONS OF COMPOUNDS EXTRACTED FROM THERMO-TREATED WOOD USING SOLVENTS OF DIFFERENT POLARITIES

Abstract: How well modified wood products perform may be influenced by their chemical compositions. Wood extractives are nonstructural constituents, many with specific biological properties, which affect the color, fragrance, hygroscopicity, durability, and acoustic properties and the drying and adhesion processes of wood. However, incomplete information is available on the extraction techniques and potential use of extractives as value-added chemical products. The main goal of this research was to explore the effects of thermo-vacuum treatment of Deodar cedar (Cedrus deodara Roxb.) and Italian alder (Alnus cordata Desf.) woods on the content and composition of extractives. Solvents with different polarities were used, including water, hexane, dichloromethane, methanol, and a benzene/ethanol mixture. Component groups in extracts were determined by gas chromatography in combination with mass spectrometry. Regardless of the treatment and solvent, the most representative extracts to be obtained from alder were acids/esters, whereas hydrocarbons were most frequently obtained from cedar. Our results revealed an interesting differential species-specific effect of solvents on the composition of extracts. Aside from benzene/ethanol, greater amounts of extracts were obtained from treated than from untreated alder, whereas the opposite was true for cedar, aside from methanol.

Keywords: Alder, Cedar, Thermo-vacuum Treatment, Extraction, GC-MS

iForest 10 (5): 824-828 (2017) - doi: 10.3832/ifor2360-010
https://iforest.sisef.org/contents/?id=ifor2360-010

Research Articles: A silvicultural stand density model to control understory in maritime pine stands

Fonseca TF, Duarte JC — 2017-09-25

Fonseca TF, Duarte JC

A SILVICULTURAL STAND DENSITY MODEL TO CONTROL UNDERSTORY IN MARITIME PINE STANDS

Abstract: The aim of this study was to provide optimal silvicultural guidelines for the maintenance of low understory vegetation cover in maritime pine (Pinus pinaster Ait.) stands in Mediterranean areas prone to the occurrence of forest fires. An extensive data set from maritime pine stands of northern Portugal was used to assess the effect of stand density on the understory cover. A statistically significant relationship between the spacing-top height factor (Fw) and the understory cover was found. An ecologically-based density regulation model was developed based on Fw = 0.21, which provided the optimal stand density and canopy cover to prevent the understory growth and proliferation, thereby reducing the vulnerability to forest fire and ensuring at the same time the highest values of stand yield. The developed model represents a supporting tool for density regulation of maritime pine stands in areas prone to forest fires. The representativeness of the supporting data set (in terms of number of sample plots and variability of the stands characteristics) provides confidence in the generalization of our results to different maritime pine stands in the Mediterranean area. This study suggests that managing stand density may be an effective adaptive management procedure which can help reducing the forest fire hazard.

Keywords: Silviculture, Density Regulation, Understory Reduction, Pinus pinaster

iForest 10 (5): 829-836 (2017) - doi: 10.3832/ifor2173-010
https://iforest.sisef.org/contents/?id=ifor2173-010

Research Articles: Predicted occurrence of ancient coppice woodlands in the Czech Republic

Madera P, Machala M, Slach T, Friedl M, Cernušáková L, Volarík D, Buček A — 2017-09-16

Madera P, Machala M, Slach T, Friedl M, Cernušáková L, Volarík D, Buček A

PREDICTED OCCURRENCE OF ANCIENT COPPICE WOODLANDS IN THE CZECH REPUBLIC

Abstract: Coppicing started in the Neolithic period and has been practiced throughout European history. This traditional silvicultural system was abandoned in many European countries during the 20th century. The Czech Republic now has a very low proportion of coppice woods (CW), as more than 1000 km2 CW were converted into high forests after World War II. Nevertheless, many CW were maintained as stored coppices, which could be the last remainders of ancient coppice woods (ACW) in the Czech Republic. Knowledge of area and distribution of stored coppices is currently missing in the Czech Republic, because they are recorded as high forests in forest management plans. Many stored forests are currently approaching the maturity age, with a high risk that these last ACW remainders will be lost; therefore, an inventory of ancient coppice woods is necessary. In our study, we develop an index of likelihood of coppice occurrence (COP) based on the distribution of habitats favourable for coppices, as well as on past and current occurrence of CW in the Czech Republic from historical maps. COP index values were then used to generate a map showing the relative likelihoods of occurrence of ACW, which can serve as a baseline to support the compilation of an ACW inventory and their mapping in the field. Our results can help prioritize forest areas to be inventoried based on their higher probabilities of ACW occurrence.

Keywords: Ancient Coppice Woodlands, Inventory, Coppice Occurrence, Cultural heritage

iForest 10 (5): 788-795 (2017) - doi: 10.3832/ifor2295-010
https://iforest.sisef.org/contents/?id=ifor2295-010

Research Articles: A comparative study of growth and leaf trait variation in twenty Cornus wilsoniana W. families in southeastern China

Cheng X, Xie H, Zhang L, Wang M, Li C, Yu M, He Z — 2017-09-02

Cheng X, Xie H, Zhang L, Wang M, Li C, Yu M, He Z

A COMPARATIVE STUDY OF GROWTH AND LEAF TRAIT VARIATION IN TWENTY CORNUS WILSONIANA W. FAMILIES IN SOUTHEASTERN CHINA

Abstract: To investigate the genotypic differences associated with the growth potential and leaf traits of Cornus wilsoniana W., we planted twenty C. wilsoniana families in southeastern China and analyzed nineteen leaf morphological and physiological traits that have potential relationships with growth. Seedling growth and leaf traits exhibited high variability among the C. wilsoniana families. The phenotypic coefficients of variation (CVs) of these traits varied from 5.33% (leaf length/leaf width, LL/LW) to 23.17% (stomatal conductance, gs), and their heritabilities (H2) ranged from 0.17 (chlorophyll a/chlorophyll b, Chla/Chlb) to 0.75 (stem height, H and Chla). There was greater genetic variation in the physiological traits than in the morphological traits. H was significantly positively correlated with instantaneous water use efficiency (WUE), Chla, Chlb and total Chl, and diameter (D) was significantly positively correlated with net photosynthetic rate (Pn), gs, WUE, Chla, Chlb and total Chl and was negatively correlated with leaf phosphorus (LP). Based on cluster analysis, three families were selected as superior families for the study area due to their seedling growth and leaf traits. These results indicate that Pn, Chla, Chlb and total Chl are good indicators to use for selecting superior families of C. wilsoniana with better growth performance; additionally, high WUE and low LP are also critical leaf traits for cultivar selection because plant adaptation to environmental conditions is important for growth performance.

Keywords: Plant Growth, Leaf Traits, Intraspecific Variation, Genetic Heritability

iForest 10 (5): 759-765 (2017) - doi: 10.3832/ifor2288-010
https://iforest.sisef.org/contents/?id=ifor2288-010

Research Articles: Relevance of terpenoids on flammability of Mediterranean species: an experimental approach at a low radiant heat flux

Della Rocca G, Madrigal J, Marchi E, Michelozzi M, Moya B, Danti R — 2017-09-02

Della Rocca G, Madrigal J, Marchi E, Michelozzi M, Moya B, Danti R

RELEVANCE OF TERPENOIDS ON FLAMMABILITY OF MEDITERRANEAN SPECIES: AN EXPERIMENTAL APPROACH AT A LOW RADIANT HEAT FLUX

Abstract: One of the major factors influencing forest fuel combustion are terpenoids, a fraction of flammable Biogenic Volatile Organic Compounds (BVOCs) produced and stored by most Mediterranean species. The qualitative and quantitative effect of terpenoids on flammability has been only partially explained. In this study several major terpenoid-storing Mediterranean species (common cypress and three pines) were considered and compared to Holm oak as a reference non-storing species. The terpenoids were quantified via gas chromatography (GC-MS) analysis from both live fine fuel (LFF) and litter samples, and the relations between flammability and the terpenoids content were investigated by categories (Monoterpenoids, oxygenated Monoterpenoids, Sesquiterpenoids). The effect of fuel moisture content and species on ignition probability of LFF was also explored. A very different ignition probability was observed at the same fuel moisture content for the different species (Pinus spp. > C. sempervirens > Q. ilex). The stored terpenoids explained 19% to 50% of the whole flammability of both LFF and litter. Fuel moisture content (FMC) did not substantially change the relative effect of terpenoids on flammability, except in C. sempervirens. Monoterpenoids do not seem to significantly affect flammability, while sesquiterpenoids greatly influenced most flammability components, though their relative effect varied among species. A relation between storing structure of terpenoids and flammability was suggested. The results of this study indicate that isoprenoids should be included in physical models of the prediction and propagation of wildfire in Mediterranean vegetation as significant factors in driving flammability.

Keywords: Fuel Moisture Content, Ignition, Live Fine Fuel, Terpene-storing Species, Terpenoids Content, Sesquiterpenoids, Litter

iForest 10 (5): 766-775 (2017) - doi: 10.3832/ifor2327-010
https://iforest.sisef.org/contents/?id=ifor2327-010

Research Articles: Use of alternative containers for promoting deep rooting of native forest species used for dryland restoration: the case of Acacia caven

De La Fuente LM, Ovalle JF, Arellano EC, Ginocchio R — 2017-09-02

De La Fuente LM, Ovalle JF, Arellano EC, Ginocchio R

USE OF ALTERNATIVE CONTAINERS FOR PROMOTING DEEP ROOTING OF NATIVE FOREST SPECIES USED FOR DRYLAND RESTORATION: THE CASE OF ACACIA CAVEN

Abstract: The size of a container determines the development and quality of root systems. In the case of taprooted forest species used for dryland reforestation, deeper containers may favour early root development and, consequently, better soil profile colonization after outplanting. Although research on container design for worldwide tree species has been developed in the last decades, technical solutions for containerized forest species with a taproot system have been poorly documented. We present a case study using Acacia caven (Mol.) Mol., which has fast-growing taproots and long lateral and superficial roots. The aim of this study is to evaluate the effects of different containers on rooting volume in the early morphological development of A. caven seedlings. Ten day-old seedlings were cultivated in five different PVC container types varying in volume, width and length (T440-Short, T440-Long, T880-Short, T880-Long, and T440-C), in a completely randomized design for one growing season. At the end of the study, whole seedling samples were destroyed to assess taproot length, lateral root biomass, and total root/shoot dry biomass. To evaluate the potential plant capacity for developing new roots, a subsequent experiment using the root growth potential test was performed successfully. Results showed that change in root volume distribution (short vs. elongated containers) had the greatest influence on seedling quality, whereas the size of container (small volume vs. large) was of minor importance. Elongated containers (35 cm to 40 cm in length) with self-pruning basal roots produced seedlings with smaller shoot/root ratios, longer root systems, and a greater ability to restart new root growth in deeper container strata. Elongated containers also prevented taproot deformation. The present study suggests that it would be appropriate to rethink container design for seedlings of deep-rooted xerophytic species destined for water-limited transplanting conditions.

Keywords: Native Tree Domestication, Root Growth Potential, Root Morphology, Seedling Quality

iForest 10 (5): 776-782 (2017) - doi: 10.3832/ifor2101-010
https://iforest.sisef.org/contents/?id=ifor2101-010

Short Communications: Vertical pit-mounds distribution of uprooted Norway spruce (Picea abies L.): field evidence in the upper mountain belt

Zadrozny P, Halecki W, Gasiorek M, Nicia P, Lamorski T — 2017-09-02

Zadrozny P, Halecki W, Gasiorek M, Nicia P, Lamorski T

VERTICAL PIT-MOUNDS DISTRIBUTION OF UPROOTED NORWAY SPRUCE (PICEA ABIES L.): FIELD EVIDENCE IN THE UPPER MOUNTAIN BELT

Abstract: Tree uprooting causes significant changes in forest habitat functioning and soil formation. In this paper soil uplifted by tree throws was compared among 15 study plots from heterogeneous Norway spruce stands of the upper mountain belt in southern Poland. Pit-mound microtopography parameters such as length, width, depth of tree-throw pits, height of the root plate, and height of mineral and organic mounds, were measured at each uprooting site. Sites were grouped in 3 age groups based on the time elapsed since uprooting. Results showed significant differences between the studied parameters among age groups. Differences were most pronounced in mean pit depth (0.52, 0.65 and 0.95 m for 5-year, 3-year, and 1-year-old pits, respectively). No significant interaction between age group and root plate height was detected by ANOVA. Regression analysis showed that pit depth decreases as root plate height increases. Redundancy analysis using pit-mound parameters as dependent variables revealed that root plate height along with slope steepness are good predictors of the volume of dislocated soil at tree-throw sites. Overall, our results suggest that the erosion expected at uprooting sites in mountain Norway spruce stands could be conveniently estimated by measuring their root plates. This may help estimate the impact of windthrow on soil microtopography and quantify its effects on soil disturbance in Norway spruce stands of the upper mountain belt.

Keywords: Bioturbation, Mountain Landscapes, Microtopography, Soil Disturbance, Tree Uprooting

iForest 10 (5): 783-787 (2017) - doi: 10.3832/ifor1959-010
https://iforest.sisef.org/contents/?id=ifor1959-010

Research Articles: Tissue carbon concentration of 175 Mexican forest species

Pompa-García M, Sigala-Rodríguez JA, Jurado E, Flores J — 2017-08-05

Pompa-García M, Sigala-Rodríguez JA, Jurado E, Flores J

TISSUE CARBON CONCENTRATION OF 175 MEXICAN FOREST SPECIES

Abstract: Reliable calculations of carbon stocks in forest ecosystems are crucial for proper implementation of global warming mitigation policies. Accurate estimations depend upon applying the correct factor of carbon (C) concentration for different forest species and tissues instead of the often assumed 50% carbon content. Despite the high forest species richness in Mexico and the increasing CO2 emissions, data on carbon concentrations in forest plant tissues are scarce. In this study, we determined variation in C concentration of different tissues for 175 plant species common in Mexican forests. C contents were estimated and contrasted for plant distribution, taxa, and plant structure (main stems, branches, twigs, bark, leaves, buds, fruits, roots and root cuticles). The mean C concentration across species was 44.7%. Species significantly differed in C concentration by tissue, environment and taxa. These multi-species data contribute to improve precision on estimates of C balance in terrestrial ecosystems, reducing the uncertainty in C inventories in Mexico and elsewhere.

Keywords: Carbon Sink, Plant Tissue C, Multi-species C, Global Warming

iForest 10 (4): 754-758 (2017) - doi: 10.3832/ifor2421-010
https://iforest.sisef.org/contents/?id=ifor2421-010

Research Articles: Temporal changes of forest species composition studied by compositional data approach

Kobal M, Kastelec D, Eler K — 2017-08-01

Kobal M, Kastelec D, Eler K

TEMPORAL CHANGES OF FOREST SPECIES COMPOSITION STUDIED BY COMPOSITIONAL DATA APPROACH

Abstract: Many ecological data are compositional and different quantitative techniques have been used to analyze such data, albeit some of them being methodologically wrong. The aim of this contribution is to apply the compositional data approach to forestry data and demonstrate the strengths of this method for percentage or relative data with infrequent zero values. Basal areas of three dominant tree species (Abies alba, Picea abies, Fagus sylvatica) in 119 forest compartments in some of the Omphalodo-Fagetum forests in Slovenia in 1954 and 2004 were used to investigate the dynamics of forest species composition over a 50-year period. For the investigated period some additional data about geomorphology and harvesting rates within the compartments were used as explanatory variables of compositional change. The species composition of each forest compartment was subjected to several methods within a compositional analysis framework: descriptive, ternary diagram-based graphical presentations, significance of compositional differences between management classes, significance of perturbation differences (the indicator of forest compositional change) and relation of the compositional change with the explanatory variables by means of compositional linear model. Results indicated that the silver fir was the dominant species in both years, but a clear reduction in silver fir proportion was observed after 50 years. The perturbation differences indicated comparatively large relative increase in the proportion of Norway spruce between 1954 and 2004. Subsequently, the perturbation differences were subjected to isometric log-transformation (ilr) and two derived ilr coordinates were further used as dependent variables in the multivariate linear model. The initial stand structure correlated well with the perturbation differences. These were also significantly correlations with salvage cutting, a consequence of silver fir decline in the 1954-2004 period. This study demonstrated that the compositional data approach can be successfully used to study forest dynamics yielding some insights into data which are not possible or even not valid using some alternative methods.

Keywords: Percentage Data, Data Transformation, Compositional Change, Compositional Linear Model, Forest Dynamics, Vegetation Shift, Omphalodo-Fagetum

iForest 10 (4): 729-738 (2017) - doi: 10.3832/ifor2187-010
https://iforest.sisef.org/contents/?id=ifor2187-010

Research Articles: Sampling strategies for high quality time-series of climatic variables in forest resource assessment

Ferrara C, Marchi M, Fares S, Salvati L — 2017-08-01

Ferrara C, Marchi M, Fares S, Salvati L

SAMPLING STRATEGIES FOR HIGH QUALITY TIME-SERIES OF CLIMATIC VARIABLES IN FOREST RESOURCE ASSESSMENT

Abstract: Many ecological studies require long-term time series of high quality. Missing data may represent a serious problem since they can affect the reliability of measured variables in specific locations. To which extent and according to which methodology a gap in time series should be filled is a major research challenge. In this study, the time-series of meteorological data relative to 13 monitoring sites from the ICP-Forest network in Italy were analysed with the aim to define the minimum number of site-specific observations, which can be considered adequate for further analysis on forest resource management. Three main climatic variables were taken into account in the analysis: air temperature, relative humidity and total precipitation. By using an increasing proportion of available data, descriptive and inferential statistic methods were applied to evaluate the amount of variability along the period of analysis (1998-2013) and associated error of estimation at seasonal level. The relative importance of each factor accounted in our analysis (season, year, variable, plot, sampling proportion) was investigated fitting a Random Forest model on the results of the bootstrapping procedure. Air temperature was the variable with a marked seasonal profile and the easiest to be represented at monthly level on a specific time period. Humidity and precipitation were more stable across the analysed time period. Trends in precipitation showed that a high amount of variability could be detected only when > 80% of valid observations were available. Humidity showed an intermediate pattern, with an exponential increase in the amount of explained variability when using an increased proportion of sampled observations. Random Forest Regression models indicated sampling proportion (i.e., number of available observations) as an important factor for trend analysis of relative air humidity and precipitation. We conclude that monthly or seasonal statistics can be proficiently estimated for both air temperature and relative humidity with a proportion of missing values higher than 50%. Conversely, a reliable analysis of intra-seasonal or intra-monthly precipitation variability requires a much higher amount of observations. In the latter case gap filling represents the only feasible solution.

Keywords: ICP-Forests, Sampling Representativeness, Missing Data, Forest Monitoring, Climate

iForest 10 (4): 739-745 (2017) - doi: 10.3832/ifor2427-010
https://iforest.sisef.org/contents/?id=ifor2427-010

Research Articles: Nearest neighbour relationships in Pinus yunnanensis var. tenuifolia forests along the Nanpan River, China

Li Y, Hui G, Yu S, Luo Y, Yao X, Ye S — 2017-08-01

Li Y, Hui G, Yu S, Luo Y, Yao X, Ye S

NEAREST NEIGHBOUR RELATIONSHIPS IN PINUS YUNNANENSIS VAR. TENUIFOLIA FORESTS ALONG THE NANPAN RIVER, CHINA

Abstract: Forest stand structural diversity can be examined at different scales. Small-scale structural changes are the basis of forest structural diversity and habitat heterogeneity, and play a key role in biodiversity conservation. Most research on forest structure has focused mainly at stand level and above, with little attention paid to fine-scale structure and correlations among different forest stand attributes. We set up four permanent plots within a secondary forest community of Pinus yunnanensis var. tenuifolia mixed forests along the Nanpan River in southern China. We analyzed their nearest-neighbor relationships using a bivariate distribution of stand spatial structural parameters (SSSP) with the aim of understanding the processes that drive structural diversity in the development of a secondary forest community. Our results revealed that communities with different disturbance histories and species compositions differed in the level of species mixture. Large, small, and medium-sized trees were well mixed within the community, both conspecific and heterospecificindividual with varying densities. All plots exhibited a uniform size differentiation pattern. Trees with different dominance levels or mixture levels were randomly distributed within the plots, and only few of these displayed clumped or regular distribution. Pearson’s correlation analysis revealed that distribution patterns may be related to species composition and diameter differentiation, though their relationship was very weak. The results of this study are relevant to optimize forest management activities in the studied stands, and promote tree growth, regeneration and habitat diversity at the fine scale.

Keywords: Bivariate Distribution, Nearest Neighbour Trees, Pinus yunnanensis, Secondary Forest, Structure Diversity

iForest 10 (4): 746-753 (2017) - doi: 10.3832/ifor2405-010
https://iforest.sisef.org/contents/?id=ifor2405-010

Research Articles: Variability of ant community composition in cork oak woodlands across the Mediterranean region: implications for forest management

Verdinelli M, Yakhlef SEB, Cossu CS, Pilia O, Mannu R — 2017-07-27

Verdinelli M, Yakhlef SEB, Cossu CS, Pilia O, Mannu R

VARIABILITY OF ANT COMMUNITY COMPOSITION IN CORK OAK WOODLANDS ACROSS THE MEDITERRANEAN REGION: IMPLICATIONS FOR FOREST MANAGEMENT

Abstract: We evaluated the potential use of ants as a powerful tool for environmental monitoring, together with the applicability of the functional group approach as an alternative method for studying ant communities in cork oak woodlands. Variations in ant community composition, diversity and functional groups were studied in two cork oak forested sites across the Mediterranean region. Ants were sampled using pitfall traps placed along linear transects at 12 sites located in the main cork districts of Italy and Morocco (Gallura in Sardinia, and Maâmora, east of Rabat). A total of 13.501 specimens were collected, belonging to 38 species (five shared species). A distinct separation in the NMDS plots between Gallura and Maâmora ant assemblages was clearly visible. Ant species composition was widely different between the two districts and significant differences were detected within the Gallura district at the species level. Opportunist species were well represented in Gallura (about 27% of average Bray-Curtis similarity) as well as cryptic species (over 23%). In the Maâmora forest, generalized Myrmicinae, hot climate specialists and opportunists contributed equally to the average similarity (together about 53%). Multi-scale ant diversity showed that the true turnover was higher in Gallura than in Maâmora. These findings support the idea that the functional group approach, rather than species diversity per se, could be considered as a valuable tool to detect the response of the ant community to environmental changes in Mediterranean cork oak woodlands. Using ants as bioindicators could help not only in detecting early warning signs of habitat disturbance, but also in defining a useful management strategy to increase the resilience of agroforestry systems under future global change scenarios.

Keywords: Cork Oak, Forest Management, Ants, Bioindicators

iForest 10 (4): 707-714 (2017) - doi: 10.3832/ifor2321-010
https://iforest.sisef.org/contents/?id=ifor2321-010

Research Articles: Chitosan oligosaccharide addition affects current-year shoot of post-transplant Buddhist pine (Podocarpus macrophyllus) seedlings under contrasting photoperiods

Wang Z, Zhao Y, Wei H — 2017-07-27

Wang Z, Zhao Y, Wei H

CHITOSAN OLIGOSACCHARIDE ADDITION AFFECTS CURRENT-YEAR SHOOT OF POST-TRANSPLANT BUDDHIST PINE (PODOCARPUS MACROPHYLLUS) SEEDLINGS UNDER CONTRASTING PHOTOPERIODS

Abstract: Chitosan oligosaccharides (COS) have been used as modifiers to promote growth and mineral nutrient utilization in crop plants, but its over-year effect on current-year shoot (CYS) of juvenile trees is still unclear. In this study, Buddhist pine (Podocarpus macrophyllus) seedlings were cultured under natural and extended photoperiods with or without COS addition for one year. In the following spring, parameters of leaf length, biomass accumulation, and N content in CYS were found to be increased by COS addition under the extended photoperiod. P concentration of COS-treated seedlings was lower under longer photoperiod, but both N and P concentrations were negatively correlated with leaf length and biomass accumulation, suggesting the utilization of N and P for growth demand of CYS. The sole addition of COS mainly resulted in whole-plant P accumulation. However, when combined with the extended photoperiod, COS addition showed over-year effect on biomass accumulation and N content in CYS of transplanted Buddhist pine seedlings. Further studies are needed to confirm these results on other tree species.

Keywords: Photoperiodism, Urban Afforestation, Yew Plum Pine, Marine Oligosaccharide, Fine Root

iForest 10 (4): 715-721 (2017) - doi: 10.3832/ifor2302-010
https://iforest.sisef.org/contents/?id=ifor2302-010

Research Articles: Effect of soil-applied lead on mineral contents and biomass in Acer cappadocicum, Fraxinus excelsior and Platycladus orientalis seedlings

Abbasi H, Pourmajidian MR, Hodjati SM, Fallah A, Nath S — 2017-07-27

Abbasi H, Pourmajidian MR, Hodjati SM, Fallah A, Nath S

EFFECT OF SOIL-APPLIED LEAD ON MINERAL CONTENTS AND BIOMASS IN ACER CAPPADOCICUM, FRAXINUS EXCELSIOR AND PLATYCLADUS ORIENTALIS SEEDLINGS

Abstract: Phytoremediation is an effective and affordable approach to extract or remove lead from contaminated soil. An understanding of the physiological responses of different species subjected to heavy metal contamination is necessary before considering their use for environmental clean-up. The objective of this study was to assess the effect of lead (Pb) on growth and nutrient uptake in three forest species native to Iran: Cappadocian maple (Acer cappadocicum), European ash (Fraxinus excelsior) and Oriental aborvitae (Platycladus orientalis). The capability of lead uptake in different organs was studied in one-year-old potted seedlings grown in contaminated soils with Pb concentration ranging from 100 to 500 mg kg-1 for six months in a nursery. Several phytoextraction parameters such as translocation factor (TF), tolerance index (TI) and bioconcentration factor (BCF) were assessed to investigate the phytoremediation potential of these species. Increasing Pb application in the soil caused a gradual decrease in dry weight of leaf and shoot of all species, while the dry weight of root remains unaffected. However, such inhibition was less marked in the conifer (P. orientalis) compared to the two broad-leaf species. Phosphorus uptake of all species slightly declined in contaminated soils. Contrastingly, Pb application did not hinder nitrogen and potassium uptake in seedlings. Atomic absorption thermo electron analysis of Pb-treated plants showed an increasing Pb accumulation in all plant compartments, although the result was more evident in the tissues of P. orientalis. This species also showed the highest values for TF, TI and BCF, indicating this conifer species as a potential candidate for phytoremediation of lead-polluted soils in Iran.

Keywords: Phytoremediation, Seedling Stage, Growth, Nutrient Uptake, Lead Accumulation, Cappadocian Maple, European Ash, Oriental Arborvitae

iForest 10 (4): 722-728 (2017) - doi: 10.3832/ifor2251-010
https://iforest.sisef.org/contents/?id=ifor2251-010

Research Articles: Acid atmospheric deposition in a forested mountain catchment

Krecek J, Palán L, Stuchlík E — 2017-07-17

Krecek J, Palán L, Stuchlík E

ACID ATMOSPHERIC DEPOSITION IN A FORESTED MOUNTAIN CATCHMENT

Abstract: Acid atmospheric deposition is harmful to both forest and aquatic ecosystems. In mountain catchments, acidification also leads to difficulties in water resource management. In 2010-2012, acid atmospheric deposition was analysed in a small forest catchment located in the upper plain of the Jizera Mountains (Czech Republic). Patch observations included monitoring of the canopy interception in two mature stands of Norway spruce (Picea abies) at elevations of 745 and 975 metres a.s.l., and twelve passive fog collectors situated along an elevation gradient between 862 and 994 metres a.s.l. In the studied area, fog (and low cloud) precipitation starts to affect the interception loss of the spruce canopy at elevations above 700 metres. However, fog drip was found to also rise with the canopy area. At the catchment scale, methods of spatial interpolation (ArcGIS 10.2) were used to approximate the aerial atmospheric deposition of water and acidic substances (sulphate, nitrate and ammonia). In the watersheds of two adjacent drinking water reservoirs, Josefuv Dul and Souš, the mean annual fog drip from the canopy was between 88 and 106 mm (i.e., 7-8% of the mean annual gross precipitation, or 10-12% of the mean annual runoff). Simultaneously, this load also deposited 658 kg km-2 of sulphur and 216 kg km-2 of nitrogen (i.e., 55% and 48% of the “open field” bulk amounts). Therefore, in headwater catchments stressed by acidification, the additional precipitation (measured under the canopy) can increase the water yield, but can also contribute to a decline in water quality, particularly in environments of low buffering capacity.

Keywords: Mountain Watershed, Spruce Forests, Acid Atmospheric Deposition, Water Resources Recharge

iForest 10 (4): 680-686 (2017) - doi: 10.3832/ifor2319-010
https://iforest.sisef.org/contents/?id=ifor2319-010

Research Articles: Predicting total and component biomass of Chinese fir using a forecast combination method

Zhang X, Cao QV, Xiang C, Duan A, Zhang J — 2017-07-17

Zhang X, Cao QV, Xiang C, Duan A, Zhang J

PREDICTING TOTAL AND COMPONENT BIOMASS OF CHINESE FIR USING A FORECAST COMBINATION METHOD

Abstract: Accurate estimates of tree biomass are critical for forest managers to assess carbon stock. Biomass of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) in southern China was assessed by three alternative methods. In the Separate model approach, total and component tree biomass was directly predicted from a regression equation as a function of tree diameter and height. In the Additive model approach, total biomass was predicted as the sum of predictions from all component biomass equations. The Forecast Combination method involved combining predictions from the total biomass equation with the sum of predictions from component biomass equations. Results indicated that the Separate model method outperformed the Additive model method in predicting total and component biomass. The drawback of the Separate model method is that the total is not equal to the sum of its components. The Forecast Combination method provided the overall best prediction for total and component biomass, and still ensured additivity of component biomass predictions.

Keywords: Additivity, Biomass Predictions, Cunninghamia lanceolata, Even-aged Plantations, Tree Allometry

iForest 10 (4): 687-691 (2017) - doi: 10.3832/ifor2243-010
https://iforest.sisef.org/contents/?id=ifor2243-010

Research Articles: Use of overburden waste for London plane (Platanus × acerifolia) growth: the role of plant growth promoting microbial consortia

2017-07-17

Karličić V, Radić D, Jovičić-Petrović J, Lalević B, Morina F, Curguz VG, Raičević V

USE OF OVERBURDEN WASTE FOR LONDON PLANE (PLATANUS × ACERIFOLIA) GROWTH: THE ROLE OF PLANT GROWTH PROMOTING MICROBIAL CONSORTIA

Abstract: Overburden waste dumps represent a huge threat to environmental quality. The reduction of their negative impact can be achieved by vegetation cover establishment. Usually, this action is complicated due to site-specific characteristics, such as nutrient deficiency, elevated metal concentration, low pH value, lack of moisture and lack of organic matter. Establishment of vegetation can be facilitated by inoculation with plant growth promoting bacteria (PGPB) which improve the physicochemical and biological properties of degraded substrates and make them more hospitable for plants. In this study we selected several strains based on the ability to produce ammonia, indole-3-acetic acid, siderophores and lytic enzymes, and to solubilize inorganic phosphates. This selection resulted in microbial consortia consisting of Serratia liquefaciens Z-I ARV, Ensifer adhaerens 10_ ARV, Bacillus amyloliquefaciens D5 ARV and Pseudomonas putida P1 ARV. The effects of PGPB consortia on one-year-old London plane (Platanus × acerifolia [Aiton] Willd.) seedlings replanted into overburden waste from Kolubara Mine Basin were examined. After seven months, inoculated seedlings were 32% higher with 45% wider root collar diameter and over 80% higher total dry biomass compared to uninoculated seedlings grown in Kolubara’s overburden. Inoculation resulted in higher amounts of total soluble proteins, higher chlorophyll and epidermal flavonoids content and higher total antioxidative capacity in the leaves. This study represents a successful search for effective PGPB strains and shows that microbial consortia have an important role in enhancing the growth of seedlings in nutrient deficient and degraded substrates such as overburden waste from open-pit coal mines. Positive response of London plane seedlings suggest that inoculation may help widening the opus of species for reforestation of post mining areas and speed up natural succession processes and recovery of degraded landscapes.

Keywords: Plant Growth Promoting Bacteria, London Plane, Overburden Waste, Revegetation

iForest 10 (4): 692-699 (2017) - doi: 10.3832/ifor2135-010
https://iforest.sisef.org/contents/?id=ifor2135-010

Research Articles: Acoustic evaluation of wood quality with a non-destructive method in standing trees: a first survey in Italy

Proto AR, Macrì G, Bernardini V, Russo D, Zimbalatti G — 2017-07-17

Proto AR, Macrì G, Bernardini V, Russo D, Zimbalatti G

ACOUSTIC EVALUATION OF WOOD QUALITY WITH A NON-DESTRUCTIVE METHOD IN STANDING TREES: A FIRST SURVEY IN ITALY

Abstract: Research and development efforts are currently underway worldwide to examine the potential use of a wide range of non-destructive technologies (NDT) for evaluating wood and wood-based materials, from the assessment of standing trees to in-place structures. For this purpose, acoustic velocity by the Fakopp time of flight (TOF) tool was used to estimate the influence of four thinning treatments performed in Southern Italy. The objective of the study was to determine if the effects of silvicultural practices on wood quality can be identified using acoustic measurement to assess the MOEd of standing trees with non-destructive method in Calabrian pine (Pinus nigra Arnold subsp. calabrica). Four hundred and fifty standing trees from four sites were non-destructively tested using a time-of-flight acoustic wave technique. The thinning trials were conducted on 60-year-old plantations of Calabrian pine in four plots under different treatments: Control (T), light thinning (A), intermediate thinning (B) and heavy thinning (C). Statistical analysis demonstrated significant stress wave time differences between the stands with moderate thinning (A and B) and those with heavy thinning (C). The results showed that tree diameter has significant influence on acoustic wave measurements and a valid relationship exists between diameter at breast height and tree velocity. The results of these studies proved that the stress wave technique can be successfully applied on standing trees.

Keywords: Modulus of Elasticity, Wood Density, Thinning, Calabrian Pine

iForest 10 (4): 700-706 (2017) - doi: 10.3832/ifor2065-010
https://iforest.sisef.org/contents/?id=ifor2065-010

Research Articles: Sensitivity analysis of RapidEye spectral bands and derived vegetation indices for insect defoliation detection in pure Scots pine stands

Marx A, Kleinschmit B — 2017-07-11

Marx A, Kleinschmit B

SENSITIVITY ANALYSIS OF RAPIDEYE SPECTRAL BANDS AND DERIVED VEGETATION INDICES FOR INSECT DEFOLIATION DETECTION IN PURE SCOTS PINE STANDS

Abstract: This study investigated the statistical relationship between defoliation in pine forests infested by nun moths (Lymantria monacha) and the spectral bands of the RapidEye sensor, including the derived normalized difference vegetation index (NDVI) and the normalized difference red-edge index (NDRE). The strength of the relationship between the spectral variables and the ground reference samples of percent remaining foliage (PRF) was assessed over three test years by the Spearman’s ρ correlation coefficient, revealing the following ranking order (from high to low ρ): NDRE, NDVI, red, NIR, green, blue, and red-edge. A special focus was directed at the vegetation indices. In both discriminant analyses and decision tree classification, the NDRE yielded higher classification accuracy in the defoliation classes containing none to moderate levels of defoliation, whereas the NDVI yielded higher classification accuracy in the defoliation classes representing severe or complete defoliation. We concluded that the NDRE and the NDVI respond very similarly to changes in the amount of foliage, but exhibit particular strengths at different defoliation levels. Combining the NDRE and the NDVI in one discriminant function, the average gain of overall accuracy amounted to 7.8 percentage points compared to the NDRE only, and 7.4 percentage points compared to the NDVI only. Using both vegetation indices in a machine-learning-based decision tree classifier, the overall accuracy further improved and reached 81% for the test year 2012, 71% for 2013, and 79% for the test year 2014.

Keywords: Forest Health, Discriminant Analysis, Pine Defoliation, Normalized Difference Red-edge Index, Decision Tree Classification

iForest 10 (4): 659-668 (2017) - doi: 10.3832/ifor1727-010
https://iforest.sisef.org/contents/?id=ifor1727-010

Research Articles: Physical, chemical and mechanical properties of Pinus sylvestris wood at five sites in Portugal

2017-07-11

Fernandes C, Gaspar MJ, Pires J, Alves A, Simões R, Rodrigues JC, Silva ME, Carvalho A, Brito JE, Lousada JL

PHYSICAL, CHEMICAL AND MECHANICAL PROPERTIES OF PINUS SYLVESTRIS WOOD AT FIVE SITES IN PORTUGAL

Abstract: The reduction of resinous species in Portuguese forest areas has caused constraints to wood industry supplies. Portugal represents the extreme southwest of Scots pine (Pinus sylvestris) natural distribution and large gaps exist in the knowledge of its wood-quality characteristics. Understanding the relationship between these traits is important for recognizing which combination of wood properties is the most suitable for specific uses. To address these questions, we assessed wood-quality traits, namely, wood-density components (microdensitometric analysis), chemical composition (NIR spectrometry) and mechanical properties (bending tests) of wood samples collected at five representative forest sites in Portugal. Our results showed that Portuguese Pinus sylvestris has good radial growth and denser wood, higher extractive content and higher stiffness and strength than northern European provenances. The lignin content was within the range attributed to softwoods. Among the Portuguese stands, trees growing at lower-altitude sites exhibited denser wood and higher mechanical properties, while trees from high-elevations showed higher amounts of lignin. Ring density was more strongly correlated with earlywood than latewood density. A negative, non-significant correlation was found between ring density and width, supporting the assumption that the higher radial growth (ring width) does not negatively affect wood quality (density). In general, chemical properties had a weak relationship with physical and mechanical properties (MOE and MOR). Both mechanical traits were positively correlated with density and growth components, supporting the assumption that trees with high radial growth do not exhibit poorer mechanical performances.

Keywords: Bending Tests, Correlations, Mechanical Traits, NIR Spectrometry, Scots Pine, Wood-Density Components, Wood Quality, X-ray Microdensitometry

iForest 10 (4): 669-679 (2017) - doi: 10.3832/ifor2254-010
https://iforest.sisef.org/contents/?id=ifor2254-010

Research Articles: Short-time effect of harvesting methods on soil respiration dynamics in a beech forest in southern Mediterranean Italy

2017-06-20

Coletta V, Pellicone G, Bernardini V, De Cinti B, Froio R, Marziliano PA, Matteucci G, Ricca N, Turco R, Veltri A

SHORT-TIME EFFECT OF HARVESTING METHODS ON SOIL RESPIRATION DYNAMICS IN A BEECH FOREST IN SOUTHERN MEDITERRANEAN ITALY

Abstract: CO2 fluxes from soil, together with soil water content and temperature have been measured over one solar year in an even-aged beech forest (Fagus Sylvatica L.) in southern Italy. We investigated the effects of three different harvested biomass removal treatments (traditional, innovative, unharvested control) on soil respiration (Rs) in three plots from May 2014 to April 2015, with the aim to evaluate the effects of such silvicultural practices on the CO2 respired from the forest floor. The influence of soil temperature and soil moisture on soil respiration was also analysed. Rs showed large variations among the treatments, with the innovative treatment resulting in significantly higher soil respiration than control and traditional treatments. There were no significant differences in soil temperature between the treatments, whereas soil water content was statistically different only in the innovative treatment. The study showed that the mean soil respiration increased with thinning intensity, confirming that after harvesting, residues remaining on the forest floor and decomposing roots may contribute to raise soil respiration, due to the higher microbial activity.

Keywords: Soil Respiration, CO2, Forest Management, Beech Forest

iForest 10 (3): 645-651 (2017) - doi: 10.3832/ifor2032-010
https://iforest.sisef.org/contents/?id=ifor2032-010

Research Articles: Long-term effects of single-tree selection cutting management on coarse woody debris in natural mixed beech stands in the Caspian forest (Iran)

Tavankar F, Nikooy M, Picchio R, Venanzi R, Lo Monaco A — 2017-06-20

Tavankar F, Nikooy M, Picchio R, Venanzi R, Lo Monaco A

LONG-TERM EFFECTS OF SINGLE-TREE SELECTION CUTTING MANAGEMENT ON COARSE WOODY DEBRIS IN NATURAL MIXED BEECH STANDS IN THE CASPIAN FOREST (IRAN)

Abstract: Coarse woody debris (CWD) has a wide range of ecological and conservation values such as maintaining biodiversity in forest ecosystems. Each forest management method can have a detrimental effect on stand structure and CWD. We analyzed the volume and density of live trees and CWD (snags and downed logs) over a long-term (30 years) selection-logging managed compartment (harvested), and compared these with values obtained from an unlogged compartment (control) in the Iranian Caspian forests. Results showed that the volume and density of live trees and CWD in the harvested area was significantly lower than in the control area, especially large size trees and CWD, very decayed CWD, and rare tree species. The ratio of snags volume to total standing volume (RSS) was significantly higher in the control (7.9%) than in the harvested area (5.2%), and the ratio of downed logs volume to trees volume (RDT) in the control area (6.3%) was significantly higher than in the harvested area (4.6%), while the ratio of downed logs volume to snags volume (RDS) was significantly higher in the harvested area (83.6%) than in the control (74%). Based on the obtained results, we recommend selection cutting forests to be managed based on CWD management plans, including appropriate cutting cycles (15-30 years) and retention of large-diameter (DBH > 75 cm) and cavity trees as a suitable habitat for many wildlife species.

Keywords: Coarse Woody Debris, Snag, Biodiversity, Selective Logging, Caspian Forest

iForest 10 (3): 652-658 (2017) - doi: 10.3832/ifor2091-010
https://iforest.sisef.org/contents/?id=ifor2091-010

Research Articles: Seeing trees from space: above-ground biomass estimates of intact and degraded montane rainforests from high-resolution optical imagery

2017-06-01

Phua MH, Ling ZY, Coomes DA, Wong W, Korom A, Tsuyuki S, Ioki K, Hirata Y, Saito H, Takao G

SEEING TREES FROM SPACE: ABOVE-GROUND BIOMASS ESTIMATES OF INTACT AND DEGRADED MONTANE RAINFORESTS FROM HIGH-RESOLUTION OPTICAL IMAGERY

Abstract: Accurately quantifying the above-ground carbon stock of tropical rainforest trees is the core component of “Reduction of Emissions from Deforestation and Forest Degradation-plus” (REDD+) projects and is important for evaluating the effects of anthropogenic global change. We used high-resolution optical imagery (IKONOS-2) to identify individual tree crowns in intact and degraded rainforests in the mountains of Northern Borneo, comparing our results with 50 ground-based plots dispersed in intact and degraded forests, within which all stems > 10 cm in diameter were measured and identified to species or genus. We used the dimensions of tree crowns detected in the imagery to estimate above-ground biomasses (AGBs) of individual trees and plots. To this purpose, preprocessed IKONOS imagery was segmented using a watershed algorithm; stem diameter values were then estimated from the cross-sectional crown areas of these trees using regression relationships obtained from ground-based measurements. Finally, we calculated the biomass of each tree (AGBT, in kg), and the AGB of plots by summation (AGBP, in Mg ha-1). Remotely sensed estimates of mean AGBT were similar to ground-based estimates in intact and degraded forests, even though small trees could not be detected from space-borne sensors. The intact and degraded forests not only had different AGB but were also dissimilar in biodiversity. A tree-centric approach to carbon mapping based on high-resolution optical imagery, could be a cheap alternative to airborne laser-scanning.

Keywords: Biomass Estimation, Crown Area, IKONOS-2, Tree Community Similarity, Sabah

iForest 10 (3): 625-634 (2017) - doi: 10.3832/ifor2204-010
https://iforest.sisef.org/contents/?id=ifor2204-010

Research Articles: Assessment of cadmium tolerance and phytoextraction ability in young Populus deltoides L. and Populus × euramericana plants through morpho-anatomical and physiological responses to growth in cadmium enriched soil

Nikolić N, Zorić L, Cvetković I, Pajević S, Borišev M, Orlović S, Pilipović A — 2017-06-01

Nikolić N, Zorić L, Cvetković I, Pajević S, Borišev M, Orlović S, Pilipović A

ASSESSMENT OF CADMIUM TOLERANCE AND PHYTOEXTRACTION ABILITY IN YOUNG POPULUS DELTOIDES L. AND POPULUS × EURAMERICANA PLANTS THROUGH MORPHO-ANATOMICAL AND PHYSIOLOGICAL RESPONSES TO GROWTH IN CADMIUM ENRICHED SOIL

Abstract: Fast growing woody plants represent effective tools for cadmium (Cd) extraction during remediation of low to medium Cd contaminated soils. Poplars are good candidates for this task because of their rapid growth rate, high biomass yield, and adaptability, as well as the availability of well-characterized clones/ genotypes with various anatomical and physiological traits. The present study evaluates the potential of Populus deltoides (clone B-81) and Populus × euramericana (clone Pannonia) for phytoremediation of Cd contamination in soil. Poplar clones were analyzed for (1) plant growth response to Cd contamination, (2) Cd accumulation, translocation, and partitioning between plant organs, and (3) morphological, anatomical and physiological responses to Cd stress as a function of biomass production. Plants were cultivated in soil moderately contaminated with Cd (8.14 mg kg-1 soil) under semi-controlled conditions for six weeks. Our results suggest that P. × euramericana and P. deltoides clones respond differently to Cd contamination. Biomass production and morphological characteristics were more negatively affected in P. × euramericana than in P. deltoides plants. However, most examined leaf structural parameters were not significantly affected by Cd. In most cases, photosynthetic characteristics and gas exchange parameters were affected by Cd treatment, but the levels and patterns of changes depended on the clone. High tolerance to applied Cd levels, as estimated by the tolerance index, was observed in both clones, but was higher in P. deltoides than P. × euramericana (82.2 vs. 66.5, respectively). We suspect that the higher tolerance to Cd toxicity observed in P. deltoides could be related to unchanged proline content and undisturbed nitrogen metabolism. Following treatment, 58.0 and 46.7% of the total Cd content was accumulated in the roots of P. × euramericana and P. deltoides, respectively, with the remainder in the stems (18.2 and 39.9%) and leaves (23.8 and 13.4%). In summary, P. deltoides displayed better phytoextraction performance under Cd exposure than P. × euramericana, suggesting its potential not only for Cd phytostabilization, but also phytoextraction projects.

Keywords: Cadmium, Phytoextraction, Poplars, Tolerance, Toxicity

iForest 10 (3): 635-644 (2017) - doi: 10.3832/ifor2165-010
https://iforest.sisef.org/contents/?id=ifor2165-010

Research Articles: Canopy temperature variability in a tropical rainforest, subtropical evergreen forest, and savanna forest in Southwest China

2017-05-17

Song Q-H, Zhang Y-P, Sha L-Q, Deng X-B, Deng Y, Wu C-S, Lu Z-Y, Chen A-G, Zhang S-B, Li P-G, Zhou W-J, Liu Y-T

CANOPY TEMPERATURE VARIABILITY IN A TROPICAL RAINFOREST, SUBTROPICAL EVERGREEN FOREST, AND SAVANNA FOREST IN SOUTHWEST CHINA

Abstract: Canopy temperature (Tc) measurements with infrared thermometry have been widely used to assess plant water status. Here, we evaluated Tc and its controlling factors in a primary tropical rainforest (TRF), subtropical evergreen broad-leaved forest (STF) and valley savanna forest (SAF) in southwestern China. We found differences between Tc and air temperature (Ta) of as much as 2.2 °C between the dry and wet seasons in the TRF. However, the canopy-to-air temperature difference (Tc-Ta) was only 0.3 °C between the dry and wet seasons in the STF. Solar radiation (SR) was the dominant factor in Tc-Ta variations during the dry and wet seasons at the three sites. The increased heating in the canopy leaves was likely the result of low stomatal conductance leading to low transpiration cooling. Changes in Tc-Ta in the TRF were highly sensitive to the degree of stomatal closure. The change in Tc-Ta was controlled by the climate, but inherent plant traits, such as stomatal conductance, also played an important controlling role.

Keywords: Canopy Temperature, Drought Stress, Microclimate, Transpiration, Leaf Energy Balance

iForest 10 (3): 611-617 (2017) - doi: 10.3832/ifor2223-010
https://iforest.sisef.org/contents/?id=ifor2223-010

Research Articles: Adjustment of photosynthetic carbon assimilation to higher growth irradiance in three-year-old seedlings of two Tunisian provenances of Cork Oak (Quercus suber L.)

Rzigui T, Cherif J, Zorrig W, Khaldi A, Nasr Z — 2017-05-17

Rzigui T, Cherif J, Zorrig W, Khaldi A, Nasr Z

ADJUSTMENT OF PHOTOSYNTHETIC CARBON ASSIMILATION TO HIGHER GROWTH IRRADIANCE IN THREE-YEAR-OLD SEEDLINGS OF TWO TUNISIAN PROVENANCES OF CORK OAK (QUERCUS SUBER L.)

Abstract: Three-year-old seedlings of two Tunisian provenances of cork oak (Quercus suber L.) differing in climatic conditions at their geographical origin were subjected to increasing light intensities. Ga’four was the provenance from the driest site and Feija from the wettest site. Low-light adapted seedlings from both provenances were exposed to two light treatments: full sunlight (HL) and low light (LL, 15% sunlight) for 40 days. The CO2-response curve of leaf net photosynthesis (An-Ci curve) established under saturated photon flux density was used to compare photosynthetic parameters between leaves subjected to continuous low light (LL leaves) and leaves transferred from low to high light (HL leaves). Transfer from low to high light significantly increased net photosynthesis (An) and dark respiration (Rd) in Ga’four provenance but not in Feija. After transfer to high irradiance, specific leaf area (SLA) did not change in either provenance. This suggested that the increase in photosynthetic capacity on a leaf area basis in HL leaves of Ga’four provenance was not due to increased leaf thickness. Only the seedlings from the Ga’four provenance were able to acclimate to high light by increasing Vcmax and Jmax.

Keywords: Quercus suber, Photosynthesis, Vcmax, Jmax, Stomatal Limitation

iForest 10 (3): 618-624 (2017) - doi: 10.3832/ifor2105-010
https://iforest.sisef.org/contents/?id=ifor2105-010

Research Articles: Estimation of aboveground forest biomass in Galicia (NW Spain) by the combined use of LiDAR, LANDSAT ETM+ and National Forest Inventory data

2017-05-15

Jiménez E, Vega JA, Fernández-Alonso JM, Vega-Nieva D, Ortiz L, López-Serrano PM, López-Sánchez CA

ESTIMATION OF ABOVEGROUND FOREST BIOMASS IN GALICIA (NW SPAIN) BY THE COMBINED USE OF LIDAR, LANDSAT ETM+ AND NATIONAL FOREST INVENTORY DATA

Abstract: Assessing biomass is critical for accounting bioenergy potentials and monitoring forest ecosystem responses to global change and disturbances. Remote sensing, especially Light Detection and Ranging (LiDAR) data combined with field data, is being increasingly used for forest inventory purposes. We evaluated the feasibility of the combined use of freely available data, both remote sensing (LiDAR data provided by the Spanish National Plan for Aerial Ortophotography - PNOA - and Landsat vegetation spectral indices) and field data (from the National Forest Inventory) to estimate stand dendrometric and aboveground biomass variables of the most productive tree species in a pilot area in Galicia (northwestern Spain). The results suggest that the models can accurately predict dendrometric and biomass variables at plot level with an R2 ranging from 0.49 to 0.65 for basal area, from 0.65 to 0.95 for dominant height, from 0.48 to 0.68 for crown biomass and from 0.55 to 0.82 for stem biomass. Our results support the use of this approach to reduce the cost of forest inventories and provide a useful tool for stakeholders to map forest stand variables and biomass stocks.

Keywords: Biomass Maps, Forest Inventory, LiDAR, Landsat Vegetation Indices

iForest 10 (3): 590-596 (2017) - doi: 10.3832/ifor1989-010
https://iforest.sisef.org/contents/?id=ifor1989-010

Technical Reports: Canopy Chamber: a useful tool to monitor the CO2 exchange dynamics of shrubland

Guidolotti G, De Dato G, Liberati D, De Angelis P — 2017-05-15

Guidolotti G, De Dato G, Liberati D, De Angelis P

CANOPY CHAMBER: A USEFUL TOOL TO MONITOR THE CO2 EXCHANGE DYNAMICS OF SHRUBLAND

Abstract: A transient state canopy-chamber was developed to monitor CO2 exchange of shrubland ecosystems. The chamber covered 0.64 m2 and it was modular with a variable height. Several tests were carried out to check the potential errors in the flux estimates due to leakages and the environment modifications during the measurements inside the chamber. The laboratory leakages test showed an error below 1% of the flux; the temperature increases inside the chamber were below 1.3 °C at different light intensity and small pressure changes. The radial blowers inside the chamber created different wind speed at different chamber height, with faster speed at the top of the chamber and the minimum wind speed that was recorded at soil level, preventing detectable effects on soil CO2 emission rates. Moreover, the chamber was tested for two years in a semi-arid Mediterranean garrigue, identifying a strong seasonality of CO2 fluxes with the highest rates during spring and lowest rates recorded during the hot dry non-vegetative summer.

Keywords: Canopy Chamber, CO2 fluxes, Cistus monspeliensis, Shrubland, Semiarid Ecosystems, Mediterranean Garrigue

iForest 10 (3): 597-604 (2017) - doi: 10.3832/ifor2209-010
https://iforest.sisef.org/contents/?id=ifor2209-010

Research Articles: Analysis and evaluation of the impact of stand age on the occurrence and metamorphosis of red heartwood

Trenčiansky M, Lieskovský M, Merganič J, Šulek R — 2017-05-15

Trenčiansky M, Lieskovský M, Merganič J, Šulek R

ANALYSIS AND EVALUATION OF THE IMPACT OF STAND AGE ON THE OCCURRENCE AND METAMORPHOSIS OF RED HEARTWOOD

Abstract: The red heartwood of beech is responsible for decreasing the market value of the most important deciduous tree species of central Europe. The aims of this study were: (i) to verify the hypothesis that stand age affects the occurrence and metamorphosis of red heartwood in beech; and (ii) to quantify the economic loss due the sale price reduction of timber affected by red heartwood. Seven even-aged beech stands of different age (87, 100, 105, 110, 115, 132, and 145 years) were selected in Slovakia, and 213 trees were cut into 961 pieces of assortments which were evaluated for the presence, form and extension of red heartwood. The economic loss caused by red heartwood was determined as the difference in price between the actual and the potential quality grades of assortments. The results confirmed that stand age significantly influence the occurrence, development, and metamorphosis of red heartwood. The average loss in timber sale price caused by red heartwood varied between 0.76 and 28.04 € m-3, depending on age and form of red heartwood, with more severe losses in stands older than 110 years. To reduce the incidence of beech red heartwood in Central Europe, a reduction of the rotation period should be considered, as well as the adoption of suitable silvicultural practices in aged beech stands.

Keywords: Red Heartwood, Economics of Beech, Timber Quality, Timber Prices

iForest 10 (3): 605-610 (2017) - doi: 10.3832/ifor2116-010
https://iforest.sisef.org/contents/?id=ifor2116-010

Research Articles: Compatible taper-volume models of Quercus variabilis Blume forests in north China

Zheng C, Wang Y, Jia L, Mason EG, We S, Sun C, Duan J — 2017-05-08

Zheng C, Wang Y, Jia L, Mason EG, We S, Sun C, Duan J

COMPATIBLE TAPER-VOLUME MODELS OF QUERCUS VARIABILIS BLUME FORESTS IN NORTH CHINA

Abstract: Compatible taper and volume models were created for Quercus variabilis Blume (cork oak) forests in North China. 174 trees were felled to obtain stem analysis data. Linear mixed effects analyses were used in modelling. Firstly, a bark thickness model was built. Then diameter at breast height over bark (DBHob) for the inner layers of the 174 trees could be calculated, based on which a total volume model was built. The estimated volume and a specific parameter restriction were then substituted into a polynomial taper model, finally the taper model was fitted and compatible taper and volume models were obtained. Four sets of models based on different data sets were separately built and compared through coefficients of determination (R2), root mean square error (RMSE), value of Akaike’s information criterion (AIC), residuals plots and histograms of residuals. Models based on data of the analyzed stems without ramicorns and simultaneously with relative diameter under 1.5 were chosen as the most precise. Further testing of the chosen models using the jackknife method for the bark thickness and total volume models and a validation data set for the taper model verified that those models can be used to predict bark thickness, diameter at a specific point along the stem, merchantable volume and total stem volume of cork oak forests in North China within specific tree diameter at breast height and height ranges.

Keywords: Quercus variabilis Blume, Dummy Variable, Box-Cox Transformation, Linear Mixed Effects Models, Compatible Taper-Volume Model

iForest 10 (3): 567-575 (2017) - doi: 10.3832/ifor2114-010
https://iforest.sisef.org/contents/?id=ifor2114-010

Research Articles: Characterization of VOC emission profile of different wood species during moisture cycles

2017-05-08

Sassoli M, Taiti C, Guidi Nissim W, Costa C, Mancuso S, Menesatti P, Fioravanti M

CHARACTERIZATION OF VOC EMISSION PROFILE OF DIFFERENT WOOD SPECIES DURING MOISTURE CYCLES

Abstract: This study addresses the characterization of volatile organic compounds (VOCs) emitted by samples of 13 different wood species, belonging to both softwoods and hardwoods groups, regularly measured at different intervals of time, after the first measurement on green wood. The same wood specimens were subjected to several cycles of water desorption and adsorption, assuming that moisture variation might play a role in both the formation and emission of VOCs. Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-TOF-MS) was used as a tool to characterize the emission of VOCs. Coupled with a multivariate class-modelling approach, this tool was able to discriminate between groups (softwood and hardwood) and in some cases between different species. However, results showed that the discriminant capacity of VOCs emission to separate species and families rapidly decreases after the first cycles of moisture variation in wood. The green wood was characterized by a richness of volatile compounds, whereas, after only the first dry cycle, wood emitted a more restricted group of compounds. We hypothesized that most of these VOCs might have originated from structural changes and degradation processes that involve the main polymers (particularly hemicellulose) constituting the cell wall of wooden cells. The results obtained are in agreement with the physical and chemical modification processes that characterize wood ageing.

Keywords: Wood, VOCs, PTR-TOF-MS, PLSDA, Wood Ageing, Moisture Content

iForest 10 (3): 576-584 (2017) - doi: 10.3832/ifor2259-010
https://iforest.sisef.org/contents/?id=ifor2259-010

Short Communications: Variation in soil carbon stock and nutrient content in sand dunes after afforestation by Prosopis juliflora in the Khuzestan province (Iran)

Moradi M, Imani F, Naji HR, Moradi Behbahani S, Ahmadi MT — 2017-05-08

Moradi M, Imani F, Naji HR, Moradi Behbahani S, Ahmadi MT

VARIATION IN SOIL CARBON STOCK AND NUTRIENT CONTENT IN SAND DUNES AFTER AFFORESTATION BY PROSOPIS JULIFLORA IN THE KHUZESTAN PROVINCE (IRAN)

Abstract: Prosopis juliflora is one of the suitable tree species used as vegetation cover for sand dunes fixation. The objectives of this study were to determine the effect of P. juliflora afforestation and its canopy coverage classes on soil carbon (C) stock and nutrient status in sand dunes after 22 years since afforestation. We hypothesized that increasing the canopy coverage would result in higher soil C stocks and nutrient content. We selected two 10-ha afforested sand dunes with 25-50% and more than 75% canopy coverage, respectively, and a 10-ha non-afforested dune (control). At each site, 15 soil samples were taken at two depths (0-5 cm and 5-50 cm). The results indicated a strong increase in the topsoil C stock (from 0.54 to 4.49 tC ha-1 in control and afforested sites, respectively), while a lower change in subsoil C stock was detected (3.0 and 4.6 tC ha-1 in control and afforested sites, respectively). Although, different canopy classes resulted in no significant differences in soil C stock, significant differences were observed for all the soil physico-chemical properties that were studied.

Keywords: Canopy Coverage, Carbon Stock, Soil Physico-chemical, C/N Ratio

iForest 10 (3): 585-589 (2017) - doi: 10.3832/ifor2137-010
https://iforest.sisef.org/contents/?id=ifor2137-010

Research Articles: Temporal development of collar necroses and butt rot in association with ash dieback

Enderle R, Sander F, Metzler B — 2017-05-05

Enderle R, Sander F, Metzler B

TEMPORAL DEVELOPMENT OF COLLAR NECROSES AND BUTT ROT IN ASSOCIATION WITH ASH DIEBACK

Abstract: In recent years collar necroses and butt rot associated with the ash dieback disease occurred with alarming frequency in Fraxinus excelsior. We analysed tree ring structures to identify the year of necrosis initiation on a set of 507 necroses on 155 stem discs from nine severely diseased south-western German stands. The number of first-time infections of trees was highest from 2010 to 2012 and slightly decreased in 2013 and 2014, whereas the total number of newly emerging individual necroses remained high. Logistic modelling of disease progression suggests that collar rot infection has almost reached its maximum incidence and that a fraction of trees will remain healthy at the root collar. On average, Hymenoscyphus fraxineus was isolated more frequently from younger collar necroses, whereas older necroses were more often colonized by Armillaria spp. Advanced stages of rot that may pose a risk to forest workers, visitors and traffic were observed already in two years-old necroses infected by Armillaria spp.

Keywords: Ash Dieback, Collar Necrosis, Disease Progression, Armillaria, Butt Rot, Epidemiology

iForest 10 (3): 529-536 (2017) - doi: 10.3832/ifor2407-010
https://iforest.sisef.org/contents/?id=ifor2407-010

Research Articles: Phenology of the beech forests in the Western Carpathians from MODIS for 2000-2015

Bucha T, Koren M — 2017-05-05

Bucha T, Koren M

PHENOLOGY OF THE BEECH FORESTS IN THE WESTERN CARPATHIANS FROM MODIS FOR 2000-2015

Abstract: The present paper introduces a satellite-based approach to the detection of phenology events in beech forests across Slovakia (the Western Carpathians) using the MOD/MYD09 products. Normalized vegetation index (NDVI) was used for determining the onset of the phenophases in spring and autumn. Double logistic sigmoid function was applied in order to fit the NDVI profile during the year. The satellite-derived phenological metrics was based on calculating the extreme values of the sigmoid function and its derivatives. Between 2000 and 2015, a time-series analysis using the linear regressions models revealed that the onset of leaf unfolding shifted at a rate of 0.8 day per decade, the onset of leaf fall was delayed at a rate of 1.9 day per decade, and the growing season (GS) extended at a rate of 1.1 day per decade. However, at a regional level, the trends were not found to be statistically significant in either case. Leaf unfolding/fall was significantly non-linearly delayed/advanced with the increase of altitude (p<0.01). GS duration varied extensively within the region. Theil-Sen estimation of GS trend revealed the median shift of 1.8 days, the range of shift being from -7.0 to +12.1 days at the 5-95 % quantile for 2000-2015. A significant inverse correlation between GS shift and GS length (p<0.01) was observed. The GS shift was positive in the sites with shorter GS and negative in the sites with longer GS.

Keywords: MODIS, NDVI, Beech, Forest Phenology, Growing Season

iForest 10 (3): 537-546 (2017) - doi: 10.3832/ifor2062-010
https://iforest.sisef.org/contents/?id=ifor2062-010

Research Articles: Climatic factors defining the height growth curve of forest species

Elli EF, Caron BO, Behling A, Eloy E, Queiróz De Souza V, Schwerz F, Stolzle JR — 2017-05-05

Elli EF, Caron BO, Behling A, Eloy E, Queiróz De Souza V, Schwerz F, Stolzle JR

CLIMATIC FACTORS DEFINING THE HEIGHT GROWTH CURVE OF FOREST SPECIES

Abstract: The aim of this study was to modify several existing biological models by including several predictive variables that take into account the effect of climatic factors on tree height growth. Tree height was measured from 2007 to 2014 on 18 trees for each of the following species: Eucalyptus urophylla × Eucalyptus grandis, Parapiptadenia rigida, Peltophorum dubium, Mimosa scabrella and Schizolobium parahybae. Different existing nonlinear models were fitted to the observed data, and the best fitting models were selected. The inclusion of climatic variables into the selected models (mainly minimum temperature and rainfall) improved their predictions of tree height growth with age, and provided more accurate estimates than those obtained by traditional nonlinear models. Simulations were carried out to explore the variation of tree height growth under different minimum temperature and precipitation regimes. The effects of frost and rainfall variation on height growth curves and their consequences for forest management are discussed.

Keywords: Von Bertalanffy-Richards’ Model, Mean Minimum Temperature, Rainfall, Frost

iForest 10 (3): 547-553 (2017) - doi: 10.3832/ifor2189-010
https://iforest.sisef.org/contents/?id=ifor2189-010

Research Articles: Influence of climate on tree health evaluated by defoliation in the ICP level I network (Romania)

Popa I, Badea O, Silaghi D — 2017-05-05

Popa I, Badea O, Silaghi D

INFLUENCE OF CLIMATE ON TREE HEALTH EVALUATED BY DEFOLIATION IN THE ICP LEVEL I NETWORK (ROMANIA)

Abstract: Defoliation is the main parameter for assessing tree crown conditions, and is the result of cumulative interactions among different types of stressors, including climate, air pollution, pests and diseases, and management systems. Here, we evaluated a long-term data series (1992-2013) provided by the ICP-Forests Level I monitoring network (16 × 16 km) in Romania. Specifically, we investigated how climate influences defoliation at different spatial and temporal levels using statistical analyses. Using periodic climatic data (mean temperature and precipitation) derived from a daily grid dataset (ROCADA) with a resolution of 0.1 × 0.1° (10 × 10 km), we quantified how climatic parameters were correlated with defoliation, which was expressed as the mean tree defoliation per plot (DEF), and the proportion of damaged trees (crown defoliation > 25% - fDEF). The cross-correlation (Spearman r) between defoliation indicators and temperature was positive and relatively constant over time for all broadleaves and conifers, combined and separately, except for Fagus sylvatica (European beech), which had a negative cross-correlation coefficient. The correlation obtained for precipitation was similar to that obtained for temperature; however, this relationship was negative (except, again, for beech). The temporal influence of temperature on defoliation was much lower than that of precipitation, which had the greatest influence in dry regions (south and southeast Romania), especially for Quercus species. Furthermore, precipitation had a positive influence in moderate climate regions for conifers that were situated outside their natural distribution ranges. For beech and conifers situated at the upper altitudinal limits, temperature was negatively correlated with defoliation, i.e., temperature had a positive influence on health status.

Keywords: Climate Change, Defoliation, Tree Species, Forest Health, Temperature, Precipitation, Level I

iForest 10 (3): 554-560 (2017) - doi: 10.3832/ifor2202-009
https://iforest.sisef.org/contents/?id=ifor2202-009

Research Articles: Selection priority for harvested trees according to stand structural indices

Li Y, Hui G, Wang H, Zhang G, Ye S — 2017-05-05

Li Y, Hui G, Wang H, Zhang G, Ye S

SELECTION PRIORITY FOR HARVESTED TREES ACCORDING TO STAND STRUCTURAL INDICES

Abstract: The selection of trees to be harvested is a core tenet of uneven-aged forest management; however, few studies have focused on the process of tree selection. A set of stand structural parameters (uniform angle index, W; mingling index, M; dominance index, U) based on tree neighbor-spatial relationships, are particularly suitable for expressing the structural characteristics of forest stands. Such indices were used to parameterize thinning in three plots (a-c, each 100 × 100 m2) in a Korean pine broad-leaved forest in northeastern China and one plot (h, 70 × 70 m2) in a pine-oak mixed forest in northwest China. Low-intensity single-tree selection was applied according to the principles of structure-based forest management (SBFM), i.e., to promote high mixture, obvious size differentiation, and random pattern with the aim of improving the overall structure of the managed plots. A group of thinning priority indices (v_ij, k_ij and z_ij) were calculated according to the bivariate distributions of the structural characteristics of harvested trees and stands before harvest. Our results demonstrated that v_ij, k_ij and z_ij adequately describe the spatial relationship between each tree and its nearest neighbors, and their combinations can be efficiently used to set thinning priorities on harvested trees with different structural characteristics. Their application can reduce the subjectivity of the selection process and improve the speed and accuracy of the choice of trees to be harvested in uneven-aged mixed forests.

Keywords: Dominance Index, Mingling Index, Thinning, SBFM, Silviculture, Uneven-aged Forest, Uniform Angle Index

iForest 10 (3): 561-566 (2017) - doi: 10.3832/ifor2115-010
https://iforest.sisef.org/contents/?id=ifor2115-010

Research Articles: Selection of optimal conversion path for willow biomass assisted by near infrared spectroscopy

Sandak A, Sandak J, Waliszewska B, Zborowska M, Mleczek M — 2017-04-20

Sandak A, Sandak J, Waliszewska B, Zborowska M, Mleczek M

SELECTION OF OPTIMAL CONVERSION PATH FOR WILLOW BIOMASS ASSISTED BY NEAR INFRARED SPECTROSCOPY

Abstract: Willow (Salix sp.) is one of the most common hardwood species suitable for short-rotation coppice. It can be converted to different products, including chemicals, fuels, fibers or furniture. It may also be used in agriculture and environmental engineering. Molecular composition of biomass and its physical properties highly influence effectiveness of its chemical, thermo-chemical or mechanical-chemical conversion. Therefore, it is challenging to provide biomass feedstock with optimized properties, best suited for further downstream conversion. The goal of this research was to establish a procedure for determination of the willow biomass optimal use cultivated in four different plantations in Poland. A special attention has been paid to the application of the near infrared spectroscopy for evaluation of biomass chemical composition and its physical properties. Near infrared spectroscopy (NIR) could be an alternative to standard analytical methods supporting the research and development of biomass production technologies. Partial least squares regression models for quantitative prediction of wood chemical components (lignin, cellulose, holocellulose, hemicellulose and extractives) and high heating values were developed. The residual prediction deviation (RPD) values confirm the applicability of chemometric models for screening in breeding programmes (for lignin, cellulose and extractives content) and for research in the case of high heating value. The analysis of NIR spectra highlighted several peculiarities in the chemical composition of the investigated willow clones. Finally, a knowledge-based expert system and a prototype automatic NIR system allowing the computation of a “suitability index” based on PLS models and dedicated to selection of optimal biomass conversion path, was developed.

Keywords: Willows, NIR Spectroscopy, Optimal Conversion, Biomass Feedstock

iForest 10 (2): 506-514 (2017) - doi: 10.3832/ifor1987-010
https://iforest.sisef.org/contents/?id=ifor1987-010

Research Articles: Soil microorganisms at the windthrow plots: the effect of post-disturbance management and the time since disturbance

Gömöryová E, Fleischer P, Pichler V, Homolák M, Gere R, Gömöry D — 2017-04-20

Gömöryová E, Fleischer P, Pichler V, Homolák M, Gere R, Gömöry D

SOIL MICROORGANISMS AT THE WINDTHROW PLOTS: THE EFFECT OF POST-DISTURBANCE MANAGEMENT AND THE TIME SINCE DISTURBANCE

Abstract: Wind disturbance is a major natural driver of forest dynamics in a large part of Europe and can affect soil properties in different ways and for different time. The present study focuses on the effects of post-disturbance management of windthrow plots in the Tatra Mountains, Slovakia, on soil microorganisms ten years after the disturbance. Their comparison with the microbial characteristics at a new windthrow plot caused by strong wind in 2014 was also carried out. Three research plots differing in the way of their management after the windstorm in 2004 (EXT, salvage plot; FIR, salvage plot affected by fire; NEX, unsalvaged plot) and the plot destroyed by strong wind in May 2014 (REX) were used for study. Ten soil samples were taken from the mineral A-horizon (depth: 0-10 cm) at each plot in autumn 2014. In soil samples, soil chemical and microbial characteristics (microbial biomass C, basal and substrate-induced respiration, N-mineralisation, catalase activity, richness and diversity of soil microbial functional groups based on the Biolog approach) were determined. Ten years after the disturbance we still observed significant differences in microbial characteristics between FIR and the other plots, with higher microbial activity at the FIR, while no significant differences were found among the other plots. The results indicate that at a higher altitude the effect of fire on soil microorganisms is more distinct than removing or not removing of fallen trees and persists even over a decade.

Keywords: Forest Soil, Soil Microorganisms, Windthrow, Fire, Postdisturbance Management

iForest 10 (2): 515-521 (2017) - doi: 10.3832/ifor2304-010
https://iforest.sisef.org/contents/?id=ifor2304-010

Research Articles: Anatomical and genetic aspects of ash dieback: a look at the wood structure

Tulik M, Zakrzewski J, Adamczyk J, Tereba A, Yaman B, Nowakowska JA — 2017-04-20

Tulik M, Zakrzewski J, Adamczyk J, Tereba A, Yaman B, Nowakowska JA

ANATOMICAL AND GENETIC ASPECTS OF ASH DIEBACK: A LOOK AT THE WOOD STRUCTURE

Abstract: Pathogen diseases are increasingly threatening forest trees under the current climate change, causing a remarkable decrease in the stability of forest ecosystems. Ash (Fraxinus excelsior L.) dieback due to Hymenoscyphus fraxineus has been noted in Poland since 1992 and has spread over many European countries. The aim of this study was to test the hypothesis that ash trees affected by dieback could exhibit a reduced vessel size and density along the trunk, as well as a lowered width of annual wood rings, leading to the weakening of water transport towards the crown. Dead and dying ash trees were sampled in a forest district severely affected by ash decline in southern Poland. Wood samples were collected at different height along the trunk and several wood anatomical characteristics of annual tree rings over the period 2002-2011 were examined. Dead trees showed a stronger reduction in radial growth than dying trees over the period considered. Moreover, the diameter of vessels increased from the crown to the base in both dead and dying trees, while the density decreased. Significant differences between dead and dying trees were detected in size and density of vessels in the period analyzed, as well as in the width of annual rings. DNA extracted from wood samples was analyzed using SSR markers and the main genetic parameters of dead and dying trees were estimated, finding similar levels of polymorphism and only slight non-significant differences between the two health groups. Our results are consistent with the hypothesis that pathogens could disrupt the hormonal control of wood formation by interfering with the polar auxin transport, progressively leading to the death of ash trees.

Keywords: Ash Trees, Microsatellites Markers, Tree Decline, Wood, Vessel Size and Density

iForest 10 (2): 522-528 (2017) - doi: 10.3832/ifor2080-010
https://iforest.sisef.org/contents/?id=ifor2080-010

Research Articles: Quantifying forest net primary production: combining eddy flux, inventory and metabolic theory

2017-04-12

Tan ZH, Hughes A, Sato T, Zhang YP, Han SJ, Kosugi Y, Goulden M, Deng XB, Cao M, Hao ZQ, Hu YH, Yu GR, Ma KP

QUANTIFYING FOREST NET PRIMARY PRODUCTION: COMBINING EDDY FLUX, INVENTORY AND METABOLIC THEORY

Abstract: Net primary production (NPP) is a central and fundamental carbon-related term in global change studies. We proposed a top-down method to quantifying forest NPP which overcomes the deficits of the traditional bottom-up method. The new top-down method combines eddy flux data, climate variables, tree inventory and metabolic theory. Our method was tested in six forests and provides reliable annual NPP estimations which are consistent with bottom-up results. Carbon use efficiency also supports this new method. Taking advantage of fine temporal resolution of our top-down method, we examined whether and confirmed NPP was well correlated with leaf area index at a seasonal scale, as suggested by past studies. The potential value of our new method as a standard NPP method is high because of the world-wide network on eddy tower and inventory plot, however further data of performance of the new method is needed to fully evaluate its performance under different conditions.

Keywords: Carbon Use Efficiency, Metabolic Theory of Ecology, Autotrophic Respiration, Biomass, Eddy Covariance

iForest 10 (2): 475-482 (2017) - doi: 10.3832/ifor2159-010
https://iforest.sisef.org/contents/?id=ifor2159-010

Research Articles: Allometric equations to assess biomass, carbon and nitrogen content of black pine and red pine trees in southern Korea

Kim C, Yoo BO, Jung SY, Lee KS — 2017-04-12

Kim C, Yoo BO, Jung SY, Lee KS

ALLOMETRIC EQUATIONS TO ASSESS BIOMASS, CARBON AND NITROGEN CONTENT OF BLACK PINE AND RED PINE TREES IN SOUTHERN KOREA

Abstract: A total of 74 Japanese black pine (Pinus thunbergii Parl.) and red pine (P. densiflora S. et Z.) trees were destructively sampled in southern Korea, which is severely affected by pine wilt disease (PWD). Species-specific allometric equations were developed to estimate the biomass, carbon (C) and nitrogen (N) content of the tree components (i.e., stem wood, stem bark, branches, needles and roots) based on the diameter at breast height (DBH) and stem diameter at 20 cm aboveground (D20). The C concentrations of the various tree components were not correlated with DBH (P > 0.05), except for the C concentration in the stem bark (r = -0.29, P < 0.05) of the black pine and the branches (r = 0.40, P < 0.05) of the red pine. However, the N concentrations in the stem wood (r = -0.53, P < 0.05), stem bark (r = -0.37, P < 0.05) and branches (r = -0.40, P < 0.05) of the black pine were negatively correlated with DBH. The mean C concentrations of the tree components were not significantly different between the black pine and red pine, except for the stem bark, whereas the mean N concentrations were significantly lower in the black pine than in the red pine, except for the stem bark. The allometric equations developed for the biomass, C and N content for all the tree components were significant (P < 0.05). The adjusted coefficient of determination (adj. R2) of the DBH allometric equations ranged from 0.66 to 0.97, while the coefficients for the D20 equations were between 0.66 and 0.95. Black pines consistently exhibited more biomass, C and N content in the tree components compared with the red pines with similar DBH or D20. These results suggest that the accuracy of estimates for biomass, C and N stocks in black pine and red pine forests could be improved by specific allometric equations for PWD-disturbed forests.

Keywords: Biomass Equations, Black Pine, Carbon Stocks, Nitrogen Stocks, Pine Wilt Disease, Red Pine

iForest 10 (2): 483-490 (2017) - doi: 10.3832/ifor2164-010
https://iforest.sisef.org/contents/?id=ifor2164-010

Research Articles: Three-dimensional forest stand height map production utilizing airborne laser scanning dense point clouds and precise quality evaluation

Sefercik UG, Atesoglu A — 2017-04-12

Sefercik UG, Atesoglu A

THREE-DIMENSIONAL FOREST STAND HEIGHT MAP PRODUCTION UTILIZING AIRBORNE LASER SCANNING DENSE POINT CLOUDS AND PRECISE QUALITY EVALUATION

Abstract: In remote sensing, estimation of the forest stand height is an ever-challenging issue due to the difficulties encountered during the acquisition of data under forest canopies. Stereo optical imaging offers high spatial and spectral resolution; however, the optical correlation is lower in dense forests than in open areas due to an insufficient number of matching points. Therefore, in most cases height information may be missing or faulty. With their long wavelengths of 0.2 to 1.3 m, P-band and L-band synthetic aperture radars are capable of penetrating forest canopies, but their low spatial resolutions restrict the use of single-tree based forest applications. In this study, airborne laser scanning was used as an effective remote sensing technique to produce large-scale maps of forest stand height. This technique produces very high-resolution point clouds and has a high penetration capability that allows for the detection of multiple echoes per laser pulse. A study area with a forest coverage of approximately 60% was selected in Houston, USA, and a three-dimensional color-coded map of forest stands was produced using a normalized digital surface model technique. Rather than being limited to the number of ground control points, the accuracy of the produced map was assessed with a model-to-model approach using terrestrial laser scanning. In the accuracy assessment, the standard deviation was used as the main accuracy indicator in addition to the root mean square error and normalized median absolute deviation. The absolute geo-location accuracy of the generated map was found to be better than 1 cm horizontally and approximately 40 cm in height. Furthermore, the effects of bias and relative standard deviations were determined. The problems encountered during the production of the map, as well as recommended solutions, are also discussed in this paper.

Keywords: Airborne Laser Scanning, Forest Stand Height Map, First Echo, Last Echo, NDSM

iForest 10 (2): 491-497 (2017) - doi: 10.3832/ifor2039-010
https://iforest.sisef.org/contents/?id=ifor2039-010

Research Articles: The effect of the calculation method, plot size, and stand density on the accuracy of top height estimation in Norway spruce stands

Ochal W, Socha J, Pierzchalski M — 2017-04-12

Ochal W, Socha J, Pierzchalski M

THE EFFECT OF THE CALCULATION METHOD, PLOT SIZE, AND STAND DENSITY ON THE ACCURACY OF TOP HEIGHT ESTIMATION IN NORWAY SPRUCE STANDS

Abstract: The aim of this study was to evaluate top height (TH) estimates for Norway spruce stands calculated according to different computational methods, and to assess the effects of stand density and plot size on TH estimation accuracy. Field data were collected from twelve 1 ha research plots located in even-aged spruce stands. Conventional estimates were found to generally overstate TH. The accuracy of TH estimation was dependent on sample plot size. TH estimation error decreased rapidly with increasing sample plot area, but only up to a certain cut-off point. Errors in TH estimation were also related to local stand density, with low and very high density levels leading to decreased accuracy. The most reliable TH estimates were obtained using the U-estimator method, which is resistant to changes in sample plot size.

Keywords: Forest Inventory, Site Index, Bias, Accuracy, Picea abies

iForest 10 (2): 498-505 (2017) - doi: 10.3832/ifor2108-010
https://iforest.sisef.org/contents/?id=ifor2108-010

Research Articles: Comparison of wood volume estimates of young trees from terrestrial laser scan data

2017-04-04

Kunz M, Hess C, Raumonen P, Bienert A, Hackenberg J, Maas HG, Härdtle W, Fichtner A, von Oheimb G

COMPARISON OF WOOD VOLUME ESTIMATES OF YOUNG TREES FROM TERRESTRIAL LASER SCAN DATA

Abstract: Many analyses in ecology and forestry require wood volume estimates of trees. However, non-destructive measurements are not straightforward because trees are differing in their three-dimensional structures and shapes. In this paper we compared three methods (one voxel-based and two cylinder-based methods) for wood volume calculation of trees from point clouds obtained by terrestrial laser scanning. We analysed a total of 24 young trees, composed of four different species ranging between 1.79 m to 7.96 m in height, comparing the derived volume estimates from the point clouds with xylometric reference volumes for each tree. We found that both voxel- and cylinder-based approaches are able to compute wood volumes with an average accuracy above 90% when compared to reference volumes. The best results were achieved with the voxel-based method (r2 = 0.98). Cylinder-model based methods (r2 = 0.90 and 0.92 respectively) did perform slightly less well but offer valuable additional opportunities to analyse structural parameters for each tree. We found that the error of volume estimates from point clouds are strongly species-specific. Therefore, species-specific parameter sets for point-cloud based wood volume estimation methods are required for more robust estimates across a number of tree species.

Keywords: Mixed Forests, Quantitative Structure Models, Voxel-based, Xylometry

iForest 10 (2): 451-458 (2017) - doi: 10.3832/ifor2151-010
https://iforest.sisef.org/contents/?id=ifor2151-010

Research Articles: Integration of tree allometry rules to treetops detection and tree crowns delineation using airborne lidar data

Sačkov I, Hlásny T, Bucha T, Juriš M — 2017-04-04

Sačkov I, Hlásny T, Bucha T, Juriš M

INTEGRATION OF TREE ALLOMETRY RULES TO TREETOPS DETECTION AND TREE CROWNS DELINEATION USING AIRBORNE LIDAR DATA

Abstract: Airborne laser scanning (ALS) has recently gained increasing attention in forestry, as ALS data may facilitate the efficient assessment of forest inventory attributes and ecological indicators related to forest stand structure. This paper presents a novel workflow for individual tree detection and tree crown delineation using ALS data. The developed point-based approach included several tree allometry rules on permissible tree heights and crown dimensions to increase the likelihood of detecting the actual tree profiles. The accuracy of the method was assessed in a heterogeneous forest with a complex stand structure in Slovakia (Central Europe). ALS measurements were taken using a RIEGL Q680i scanner at 700 m of height with a point density of 20 echoes per m2. The ground reference data included the measured positions and dimensions of 1332 trees in nine plots distributed across the region. We found that the number of individual trees detected by the algorithm using ALS data was systematically underestimated by 34 ± 15% relative to the reference data. The delineated crown coverage was underestimated by 2 ± 6% as well, but the latter difference was not statistically significant (p>0.05).

Keywords: Tree Allometry, Airborne Laser Scanning, Individual Tree Detection, Point-based Approach

iForest 10 (2): 459-467 (2017) - doi: 10.3832/ifor2093-010
https://iforest.sisef.org/contents/?id=ifor2093-010

Short Communications: Variation in growth, photosynthesis and water-soluble polysaccharide of Cyclocarya paliurus under different light regimes

Yang W, Liu Y, Fang S, Ding H, Zhou M, Shang X — 2017-04-04

Yang W, Liu Y, Fang S, Ding H, Zhou M, Shang X

VARIATION IN GROWTH, PHOTOSYNTHESIS AND WATER-SOLUBLE POLYSACCHARIDE OF CYCLOCARYA PALIURUS UNDER DIFFERENT LIGHT REGIMES

Abstract: As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. Responses of growth, photosynthesis and phytochemical accumulation to light environment are useful informations to determine suitable habitat conditions for the cultivation of C. paliurus. A split-plot design with five light quality and three light intensity levels was adopted to compare the variations in plant growth, photosynthesis and water-soluble polysaccharide yield in C. paliurus leaves. Both light intensity and quality treatments significantly affected total biomass, photosynthetic rate and water-soluble polysaccharide yield in C. paliurus leaves. Treatments under red light and blue light with 1000 μmol m-2 s-1 achieved the highest values of biomass growth, photosynthetic rate, specific dry leaf mass per area and accumulation of water-soluble polysaccharide. These results indicate that red light and blue light with higher light intensity level were effective for increasing plant growth, photosynthesis and production of water-soluble polysaccharide in C. paliurus leaves. Manipulating light conditions might be an effective means to improve biomass and achieve higher water-soluble polysaccharide yield in C. paliurus plantations.

Keywords: Cyclocarya paliurus, Environmental Factor, Biomass Production, Phytochemicals, Photosynthesis

iForest 10 (2): 468-474 (2017) - doi: 10.3832/ifor2185-010
https://iforest.sisef.org/contents/?id=ifor2185-010

Research Articles: A resource capture efficiency index to compare differences in early growth of four tree species in northern England

Leslie AD, Mencuccini M, Perks MP — 2017-03-24

Leslie AD, Mencuccini M, Perks MP

A RESOURCE CAPTURE EFFICIENCY INDEX TO COMPARE DIFFERENCES IN EARLY GROWTH OF FOUR TREE SPECIES IN NORTHERN ENGLAND

Abstract: At a trial established in Cumbria, northern England, significant differences in growth rate between tree species were apparent, with cider gum (Eucalyptus gunnii) and alder (Alnus glutinosa) exhibiting most rapid volume and biomass accumulation. Estimations were made of leaf area, specific leaf area, leaf area ratio (based on stem mass not whole tree mass) and length of growing season. These measurements were undertaken to explain tree growth difference and developing a growth potential index based on growing season length and leaf area. The high leaf area of cider gum and alder explained some of their superior growth, while alder also had the longest period in leaf, compared with ash (Fraxinus excelsior) and sycamore (Acer pseudoplatanus). The slow growth of ash can be explained by the short period in leaf and also the relatively low leaf area ratio. Leaf area to stem weight also differed between species with that of ash being relatively low. Specific leaf area was also low for ash, a trait shared with cider gum, which suggests that these species invest highly in each unit of leaf area. Of the tree species assessed, the length of the growing season was longest for alder, enabling it to maintain growth for a longer period. By multiplying growing season by leaf area a resource capture index was calculated and this explained 56% of the variation in stem dry weight between trees. The potential and limitations for using this index are discussed.

Keywords: Eucalyptus gunnii, Fraxinus excelsior, Acer pseudoplatanus, Alnus glutinosa, Resource Capture Efficiency

iForest 10 (2): 397-405 (2017) - doi: 10.3832/ifor2248-010
https://iforest.sisef.org/contents/?id=ifor2248-010

Research Articles: Damage assessment to subtropical forests following the 2008 Chinese ice storm

Zhou B, Wang X, Cao Y, Ge X, Gu L, Meng J — 2017-03-24

Zhou B, Wang X, Cao Y, Ge X, Gu L, Meng J

DAMAGE ASSESSMENT TO SUBTROPICAL FORESTS FOLLOWING THE 2008 CHINESE ICE STORM

Abstract: Ice storm is a major form of extreme climatic event and may occur more frequently in the future under a changing climate. The 2008 Chinese ice storm provided a natural laboratory to study ecosystem responses and feedbacks to climate variability and extreme events. Four typical subtropical forests (Chinese fir plantation, pine plantation, moso bamboo plantation, and secondary mixed broadleaved forest) were selected to assess the damage caused by the ice storm. The ice damage rate of typical subtropical forests varied between 25% and 81%. The secondary broadleaved forest had most extensive damage while the Chinese fir plantation experienced the most severe damage. Exotic pine species (Pinus elliottii Engelm. and Pinus taeda Linn.) were more severely damaged than the native species, Pinus massoniana Lamb. Ice damage was also affected by tree/culm size, age, stand density, site altitude, and management practices. Large-sized trees/culms were more vulnerable to stem breakage, decapitation, and uprooting, while small-sized trees/culms were more vulnerable to bending and leaning. Younger trees/culms had the highest damage rate, and were more susceptible to bending damage. Ice damage rate increased linearly with the stand density, and higher altitude led to a significant increase of stem breakage. Oleoresin tapping aggravated the damage to pine trees. Resistance of trees to ice damage is an emergent consequence of tree attributes, species origin, site conditions, and human disturbance. Forest silviculture and management practices can play significant roles in controlling forest susceptibility to extreme events. Inappropriate utilization of non-timber forest products can reduce trees’ resistance to extreme events. For sustainable forest development, balance needs to be achieved between the high productivity of introduced exotic tree species and the resistance of native species to extreme climatic events.

Keywords: Ice Damage, Secondary Mixed Broadleaved Forest, Chinese Fir, Moso Bamboo, Pine, Forest Management

iForest 10 (2): 406-415 (2017) - doi: 10.3832/ifor1619-009
https://iforest.sisef.org/contents/?id=ifor1619-009

Research Articles: Analysis of biometric, physiological, and biochemical traits to evaluate the cadmium phytoremediation ability of eucalypt plants under hydroponics

Iori V, Pietrini F, Bianconi D, Mughini G, Massacci A, Zacchini M — 2017-03-24

Iori V, Pietrini F, Bianconi D, Mughini G, Massacci A, Zacchini M

ANALYSIS OF BIOMETRIC, PHYSIOLOGICAL, AND BIOCHEMICAL TRAITS TO EVALUATE THE CADMIUM PHYTOREMEDIATION ABILITY OF EUCALYPT PLANTS UNDER HYDROPONICS

Abstract: Wastewater reclamation and reuse represent a feasible solution to meet the growing demand for safe water. An environmentally sustainable technology such as phytoremediation is targeted for the reclamation of polluted waters. To this end, the capability of different plant species to tolerate and accumulate pollutants has to be investigated. In this work, eucalypt plants were studied by analysing biometric, physiological, and biochemical parameters related to cadmium (Cd) tolerance and accumulation in two clones (“Velino ex 7” and “Viglio ex 358”) of Eucalyptus camaldulensis Dehnh. × E. globulus subsp. bicostata (Maiden, Blakely & J.Simm.) J.B. Kirkp exposed to 50 μM CdSO4 under hydroponics for three weeks. The results indicated that both eucalypt clones have a valuable tolerance to cadmium, expressed as the tolerance index (Ti). Biometric investigations showed that, regardless of the clone, the metal exposure affected most parameters related to biomass allocation and leaf growth. On the contrary, significant differences were found between the clones with respect to the chlorophyll content and the Chl a to Chl b ratio. These findings were also confirmed from the analysis of chlorophyll fluorescence transient (OJIP) using the JIP test. Cadmium accumulation occurred in both clones and in particular in the roots, with a poor amount of metal reaching the aerial parts, and the Velino clone showed the highest Cd accumulation. The metal uptake ratio and the phytoextraction efficiency highlight a good Cd phytoremoval ability, especially for the Velino clone. The results are discussed taking into account that, in wastewater phytoremediation systems, root biomass can be completely harvested allowing for the removal of the absorbed metal. Finally, the notable tolerance to submersion and the large environmental adaptability of eucalypt suggest that this plant species represents an interesting candidate for the phytoremediation of Cd-polluted wastewaters.

Keywords: Heavy Metals, Metal Tolerance, Wastewater, Forest Plants, Chlorophyll Fluorescence, Rhizofiltration

iForest 10 (2): 416-421 (2017) - doi: 10.3832/ifor2129-009
https://iforest.sisef.org/contents/?id=ifor2129-009

Research Articles: Genetic analysis of Latvian Salix alba L. and hybrid populations using nuclear and chloroplast DNA markers

Rungis D, Laivins M, Gailite A, Korica A, Lazdina D, Skipars V, Veinberga I — 2017-03-24

Rungis D, Laivins M, Gailite A, Korica A, Lazdina D, Skipars V, Veinberga I

GENETIC ANALYSIS OF LATVIAN SALIX ALBA L. AND HYBRID POPULATIONS USING NUCLEAR AND CHLOROPLAST DNA MARKERS

Abstract: Latvia is at the northern border of the species range of S. alba L. in Europe, and there has been some debate whether the Latvian populations of S. alba are autochthonous, as this species has long been planted in Latvia as an ornamental tree in gardens, parks and roadsides. In addition, there is increasing interest in the use of several Salix species (including S. alba) as bioenergy crops. Natural S. alba stands throughout Latvia, as well as stands of possibly hybrid origin were analysed using nuclear and chloroplast markers. Our results showed that S. alba populations are probably natural, and that the rate of vegetative reproduction is low, supporting the evidence that Latvia is within the natural range of S. alba. These results provide the basis for the identification of possibly introduced or artificially regenerated stands of S.alba in Latvia. In addition, our results confirm that S. alba hybridises with S. fragilis, and that natural stands including hybrid individuals can be established. The analysis of chloroplast markers indicated that the predominant hybridisation occurs by fertilisation of S. fragilis by S. alba pollen; however, the extent of haplotype sharing between these two species should be further investigated.

Keywords: Willow, Population Structure, Autochthonous, Provenance

iForest 10 (2): 422-429 (2017) - doi: 10.3832/ifor2004-009
https://iforest.sisef.org/contents/?id=ifor2004-009

Research Articles: Heuristic forest planning model for optimizing timber production and carbon sequestration in teak plantations

Quintero-Méndez MA, Jerez-Rico M — 2017-03-24

Quintero-Méndez MA, Jerez-Rico M

HEURISTIC FOREST PLANNING MODEL FOR OPTIMIZING TIMBER PRODUCTION AND CARBON SEQUESTRATION IN TEAK PLANTATIONS

Abstract: We developed a forest planning model integrating two operational scales (single-stand and forest levels) for the optimization of timber production and carbon sequestration in forest teak (Tectona grandis L. f.) plantations. At the stand level, growth and yield simulations using a heuristic thinning optimizer provided a set of near-optimal thinning regimes for individual stands differing on initial spacing and site quality, given biological, silvicultural, and financial constraints. The set of near-optimal thinning regimes obtained were then used as input of the forest-level model, which generated optimal harvest plans for the whole plantation by simultaneously maximizing the net present value of merchantable wood and carbon sequestration. The net amount of carbon captured by the biomass and the emissions produced by decomposition of woody debris and timber products after harvest were estimated. The growth and yield model was based on a system of differential equations incorporating heuristics (genetic algorithms) to optimize age and intensity of thinnings. The full model can handle the optimization of harvest schedules for projects up to 10.000 ha and 200 stands and was tested on a validation dataset including teak plantations from Venezuela and other Latin American countries. Results indicated that regimes favoring carbon sequestration reduce the benefits of timber production, and equal profitability of carbon sequestration and timber production was obtained for carbon prices over 40 $US Gg-1. Sensitivity analysis showed that the proposed model is sensible to variation in growth rates, carbon and timber prices, and production quotas, and barely sensible to harvest and transport costs. The developed model has a modular structure that allows its calibration to incorporate data from a wide range of management regimes for teak and other forest species.

Keywords: Forest Planning, Harvest Scheduling, Optimization, Heuristics, Carbon Sequestration, Tectona grandis

iForest 10 (2): 430-439 (2017) - doi: 10.3832/ifor1733-009
https://iforest.sisef.org/contents/?id=ifor1733-009

Research Articles: Gnomoniopsis castaneae associated with Dryocosmus kuriphilus galls in chestnut stands in Sardinia (Italy)

Seddaiu S, Cerboneschi A, Sechi C, Mello A — 2017-03-24

Seddaiu S, Cerboneschi A, Sechi C, Mello A

GNOMONIOPSIS CASTANEAE ASSOCIATED WITH DRYOCOSMUS KURIPHILUS GALLS IN CHESTNUT STANDS IN SARDINIA (ITALY)

Abstract: Invasive fungal pathogens and pests of sweet chestnut (Castanea sativa Mill.) forests drastically reduce their productivity. The recently described Gnomoniopsis castaneae is one of the main agents involved in the epidemic of brown rot of chestnut nuts worldwide. In 2014, during an investigation aimed at evaluating the health status of chestnut forests in Sardinia, a high incidence of necrotic galls induced by the Asian gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera, Cynipidae) was observed. Several fungal isolates were consistently isolated from necrotic gall tissues. Based on their morphological characters and analyses of both the ITS and EF1-α-coding gene sequences, all isolates were identified as Gnomoniopsis castaneae.

Keywords: Galls Necrosis, Brown Nut Rot, Invasive Pests, Forest Pathogens

iForest 10 (2): 440-445 (2017) - doi: 10.3832/ifor2064-009
https://iforest.sisef.org/contents/?id=ifor2064-009

Research Articles: Shear modulus of old timber

Cavalli A, Cibecchini D, Goli G, Togni M — 2017-03-24

Cavalli A, Cibecchini D, Goli G, Togni M

SHEAR MODULUS OF OLD TIMBER

Abstract: Interest in both the time effect on the timber mechanical properties and the reuse of old solid timbers has prompted many research works since the 1970s, mainly focusing on evaluating bending strength (MOR) and stiffness (MOE). However, only few studies have investigated the effect of aging on shear modulus (G). In this work, transverse vibration test is used to calculate G and MOE of over 80 old timber beams. The MOE/G ratio and the relationship between G and different timber features are investigated. The main outcome of the research confirms that the MOE/G ratio is around 20, close to the value reported in literature for new solid timber. No relationship exists between G and MOE (r2=0.07) or between G and other timber features. When density and knots are used as predictors in a multiple regression model, the G prediction improves (r2=0.22). This work confirms that G is not affected by the age of timber.

Keywords: Flexural Vibration, Old Timber, Historical Timber Buildings, Reclaimed Timber

iForest 10 (2): 446-450 (2017) - doi: 10.3832/ifor1787-009
https://iforest.sisef.org/contents/?id=ifor1787-009

Research Articles: Long-term changes in surface-active beetle communities in a post-fire successional gradient in Pinus brutia forests

Kaynas BY — 2017-03-16

Kaynas BY

LONG-TERM CHANGES IN SURFACE-ACTIVE BEETLE COMMUNITIES IN A POST-FIRE SUCCESSIONAL GRADIENT IN PINUS BRUTIA FORESTS

Abstract: Fire is one of the most important ecological factors for many ecosystem types. Since prehistoric times, synergistic effects of fires and humans have led to changes in Eastern Mediterranean ecosystems. The effects of fire on different trophic levels, particularly regarding plants, have been examined intensively in fire-induced ecosystems. In this study, we aimed to study long-term changes in beetle community structure after fire in Pinus brutia Ten. forests. Five sites burned in different years and a control site unburned for at least 50 years were selected. Beetle sampling was conducted using four pit-fall traps in each of four transects in three replication plots at every successional site and in two plots at the control site. Microhabitat variables related to vegetation structure and litter layer were recorded and associated with abundances of beetles and feeding groups. The results showed that total, wood-eating, and predator beetles showed a decreasing trend of abundance along the successional gradient after fire. In contrast to these groups, herbivores tended to increase towards the late successional stages. Middle and late successional stages were important in terms of species richness, species diversity and evenness of beetle communities and feeding groups. The characteristics of vegetation and litter layer changed with successional gradient, playing a decisive role in the structure of beetle communities at successional sites. According to the data presented here, a mosaic structure consisting of different successional stages is very important to sustain high species diversity in beetle communities.

Keywords: Forest Fires, Coleoptera, Brutia Pine, Resilience, Autosuccession

iForest 10 (2): 376-382 (2017) - doi: 10.3832/ifor2140-009
https://iforest.sisef.org/contents/?id=ifor2140-009

Research Articles: Effects of thinning and pruning on stem and crown characteristics of radiata pine (Pinus radiata D. Don)

2017-03-16

Fernández MP, Basauri J, Madariaga C, Menéndez-Miguélez M, Olea R, Zubizarreta-Gerendiain A

EFFECTS OF THINNING AND PRUNING ON STEM AND CROWN CHARACTERISTICS OF RADIATA PINE (PINUS RADIATA D. DON)

Abstract: Simultaneous applications of thinning and pruning are common silvicultural practices in radiata pine (Pinus radiata) forest plantations. Their separate effects on tree growth and wood quality have been well studied, but their combined effect is not clear yet. The aim of this study is to identify how thinning and pruning together affect the stem structure and properties of the pruned but also the unpruned section of the trees (the portions formed immediately after the application of these management efforts). The effects of pruning and thinning on the number of growth units per year, internode length, number of branches, and branch diameters was analyzed in managed and unmanaged stands of radiata pine grown in Chile. When used jointly, these practices generated larger individual tree volumes (135% more) and clear wood in the pruned logs; however, they also reduced the sawn wood quality of the unpruned stem section for some years after the silvicultural interventions. The managed trees showed more growth units per annual shoot and shorter internodes, thus generating more knotty wood. Moreover, managed trees showed more taper. As trees of the managed stand restore the foliar biomass lost due to pruning, managed and unmanaged stands approach the same level of canopy closure, and differences minimize.

Keywords: Annual Shoot, Silviculture Management, Branching, Knots, Tree Volume, Taper, Wood Quality

iForest 10 (2): 383-390 (2017) - doi: 10.3832/ifor2037-009
https://iforest.sisef.org/contents/?id=ifor2037-009

Research Articles: Successional leaf traits of monsoon evergreen broad-leaved forest, Southwest China

Liu W, Su J — 2017-03-16

Liu W, Su J

SUCCESSIONAL LEAF TRAITS OF MONSOON EVERGREEN BROAD-LEAVED FOREST, SOUTHWEST CHINA

Abstract: Understanding the variation of functional traits of plant species along forest successional gradients may provides useful insights into community assemblages. However, species performance during forest succession is controversial. We explored the variation of leaf traits along a forest succession by examining ten leaf traits in four successional stages in a monsoon evergreen broad-leaved forest in Southwest China. Results showed significant differences in all leaf traits except leaf area and leaf carbon content among the successional stages. Five leaf traits were highly correlated to successional stage, while the first principal component showed no correlation with successional stage. The first principal component accounted for 56.1% of the total variation in all ten leaf traits. Almost 50% of the relationships between leaf traits differed along the examined successional gradient, indicating that leaf traits were affected by the successional stage.

Keywords: Specific Leaf Area, Leaf Chemistry, Maximum Photosynthesis, Successional Stage, Monsoon Evergreen Broadleaved Forest

iForest 10 (2): 391-396 (2017) - doi: 10.3832/ifor2045-009
https://iforest.sisef.org/contents/?id=ifor2045-009

Research Articles: Electrochemical in-situ studies of solar mediated oxygen transport and turnover dynamics in a tree trunk of Tilia cordata

Tötzke C, Cermak J, Nadezhdina N, Tributsch H — 2017-03-07

Tötzke C, Cermak J, Nadezhdina N, Tributsch H

ELECTROCHEMICAL IN-SITU STUDIES OF SOLAR MEDIATED OXYGEN TRANSPORT AND TURNOVER DYNAMICS IN A TREE TRUNK OF TILIA CORDATA

Abstract: Platinum electrodes were implanted into the xylem of a lime tree (Tilia cordata) stem and solar-induced electrochemical potential differences of up to 120 mV were measured during the vegetative period and up to 30 mV in winter. The time dependent curves were found to be delayed with respect to solar radiation, sap flow activity, temperature and vapor pressure deficit. A general equation for the potential difference was derived and simplified by analyzing the effect of temperature and tensile strength. The potential determining influence of oxygen concentration on the respective location of the platinum electrode was identified as the principal phenomenon measured. A systematic analysis and investigation of the observed periodic oxygen concentration signals promises new information on sap flow, oxygen diffusion through tree tissues and on oxygen consumption related to the energy turnover in tree tissues.

Keywords: Tree Stems, Oxygen Transport, Xylem, Sap Flow, Tree Metabolism, Electrical Potential

iForest 10 (2): 355-361 (2017) - doi: 10.3832/ifor1681-010
https://iforest.sisef.org/contents/?id=ifor1681-010

Research Articles: Tree species diversity of three Ghanaian reserves

Cazzolla Gatti R, Vaglio Laurin G, Valentini R — 2017-03-07

Cazzolla Gatti R, Vaglio Laurin G, Valentini R

TREE SPECIES DIVERSITY OF THREE GHANAIAN RESERVES

Abstract: Among tropical areas, Africa is considered to be poor in terms of biodiversity as compared with Amazon or South-East Asia, especially with respect to forest diversity. Despite this lower diversity, some African tropical zones, such as Ghana, harbour a plethora of species, particularly of trees. Unfortunately, as a result of anthropogenic impacts, biological diversity in West Africa dramatically decreased in the last decades, with very limited reference to evaluate the amount of the loss. Due to these growing pressure, a collection of relevant biodiversity information in this region seems to be urgent. We surveyed 127 temporary plots randomly distributed within 3 protected areas in Ghana and we collected data on tree (dbh>10 cm) species richness and their abundances. We also performed α, and β diversity analyses, and estimated the effective number of species, adopting various indices and approaches to provide further information on each assemblage. The main goals of this research were: (i) to provide a wide tree species database (abundance-based data), together with some biodiversity analyses; (ii) to estimate the sampling effort needed for next biodiversity surveys in the same and similar regions; and (iii) to calculate some indices useful to monitor the future of these protected areas both in terms of conservation and biodiversity research.

Keywords: Ghana, Protected Areas, Forests, Database

iForest 10 (2): 362-368 (2017) - doi: 10.3832/ifor2056-010
https://iforest.sisef.org/contents/?id=ifor2056-010

Research Articles: Can traditional selective logging secure tree regeneration in cloud forest?

Ortiz-Colín P, Toledo-Aceves T, López-Barrera F, Gerez-Fernández P — 2017-03-07

Ortiz-Colín P, Toledo-Aceves T, López-Barrera F, Gerez-Fernández P

CAN TRADITIONAL SELECTIVE LOGGING SECURE TREE REGENERATION IN CLOUD FOREST?

Abstract: Unplanned selective logging for charcoal and firewood is a common practice in tropical montane cloud forest (TMCF), a high priority ecosystem for biodiversity conservation at the global scale. However, limited information is available regarding the impact of such logging on forest regeneration. We evaluated the abundance and composition of tree regeneration in four TMCF sites subject to traditional selective logging in southern Mexico. At each site, we calculated a tree extraction index based on the number of stumps, logs and charcoal kilns and established six 200 m2 plots where the abundance of adult, sapling and seedling trees were recorded and canopy cover estimated. Based on the extraction index and estimated basal area values, two sites each were classified as being of low (L) and high (H) logging intensity; the extraction index was three times lower in L (7.5 and 9.2) than in H (35 and 35) sites, while basal area was significantly higher in L than in H sites (80.2 ± 10.2 vs. 41.9 ± 4.96 m2 ha-1, respectively). No significant differences were found among sites in terms of canopy cover, diameter and density of adult trees or in the density of saplings and seedlings (0.72 individuals m-2). In all sites, species of intermediate shade-tolerance dominated the regeneration (76%), followed by the shade-tolerant (23%) and pioneer (1%) species. Regeneration of Quercus spp. (four species) dominated at all sites (50.5%); this is a group of particular interest to the local communities because of its utility for firewood and charcoal. The similarity in composition between adult and regenerating tree species was relatively high in all of the sites (Morisita-Horn Index L1=0.86, L2=0.64, H1=0.69 and H2=0.71). These results indicate that, under the evaluated selective logging intensities, TMCF can sustain sufficient regeneration of Quercus spp. and thus presents an opportunity for sustainable management. The legacy effects of traditional selective logging on TMCF tree regeneration are discussed.

Keywords: Firewood, Forest Management, Mexico, Quercus, Seedlings, Timber Harvesting, Tropical Montane Cloud Forest, Disturbance

iForest 10 (2): 369-375 (2017) - doi: 10.3832/ifor1937-009
https://iforest.sisef.org/contents/?id=ifor1937-009

Research Articles: High resolution biomass mapping in tropical forests with LiDAR-derived Digital Models: Poás Volcano National Park (Costa Rica)

Fernández-Landa A, Navarro JA, Condés S, Algeet-Abarquero N, Marchamalo M — 2017-02-23

Fernández-Landa A, Navarro JA, Condés S, Algeet-Abarquero N, Marchamalo M

HIGH RESOLUTION BIOMASS MAPPING IN TROPICAL FORESTS WITH LIDAR-DERIVED DIGITAL MODELS: POáS VOLCANO NATIONAL PARK (COSTA RICA)

Abstract: Tropical forests play a key role in global carbon cycle. Reducing Emissions from Deforestation and forest Degradation (REDD+) program requires reliable mechanisms for Monitoring, Reporting and Verification (MRV). In this regard, new methods must be developed using updated technologies to assess carbon stocks. The combination of LiDAR technology and in situ forest networks allows the estimation of biomass with high resolution in low data environments, such as tropical countries. However, the evaluation of current LiDAR methods of biomass inventory, and the development of new methodologies to reduce uncertainty and increase accuracy, is still needed. Our aim is to evaluate new methodologies of spatially explicit LiDAR biomass inventories based on local and general plot-aggregate allometry. For this purpose, 25 field plots were inventoried, covering the structural and ecological variability of Poás Volcano National Park (Costa Rica). Important differences were detected in the estimation of aboveground biomass (92.74 t ha-1 considering the mean value of plot sample) depending on the chosen tree allometry. We validated the general aboveground biomass plot-aggregate allometry proposed by Asner & Mascaro (2014) in our study area, and we fitted two specific models for Poás forests. Both locals and general models depend on LiDAR top-of-canopy height (TCH), basal area (BA) and wood density. Small deviations in the wood density plot sample (0.60 ± 0.05) indicated that a single wood density constant value could be used throughout the study area. A BA-TCH origin forced linear model was fitted to estimate basal area, as suggested by the general methodology. Poás forest has a larger biomass density for the same THC compared to the rest of the forests previously studied, and shows that the BA-TCH relationship might have different trends in each life zone. Our results confirm that the general plot-aggregate methodology can be easily and reliably applied as aboveground biomass in a new area could be estimated by only measuring BA in field plots to obtain a local BA-TCH regression. For both local and general methods, the estimation of BA is critical. Therefore, the definition of precise basal area field measurement procedures is decisive to achieve reliable results in future studies.

Keywords: Carbon, Remote Sensing, REDD, LiDAR, Plot-level Allometry, Biomass, Basal Area

iForest 10 (1): 259-266 (2017) - doi: 10.3832/ifor1744-009
https://iforest.sisef.org/contents/?id=ifor1744-009

Research Articles: Comparing image-based point clouds and airborne laser scanning data for estimating forest heights

Ullah S, Adler P, Dees M, Datta P, Weinacker H, Koch B — 2017-02-23

Ullah S, Adler P, Dees M, Datta P, Weinacker H, Koch B

COMPARING IMAGE-BASED POINT CLOUDS AND AIRBORNE LASER SCANNING DATA FOR ESTIMATING FOREST HEIGHTS

Abstract: Accurate and updated knowledge of forest tree heights is fundamental in the context of forest management. However, measuring canopy height over large forest areas using traditional inventory techniques is laborious, time-consuming and excessively expensive. In this study, image-based point clouds produced from stereo aerial photographs (AP) were used to estimate forest height, and compared to Airborne Laser Scanning (ALS) data. We generated image-based Canopy Height Models (CHM) using different image-matching algorithms (SGM: Semi-Global Matching; eATE: enhanced Automatic Terrain Extraction), which were compared with a pure ALS-derived CHM. Additionally, plot-level height and density metrics were extracted from CHMs and used as explanatory variables for predicting the Lorey’s mean height (LMH), which was measured at 296 reference points on the ground. CHMSGM and CHMALS showed similar results in predicting LMH at sample plot locations (RMSE% = 8.54 vs. 7.92, respectively), while CHMeATE had lower accuracy (RMSE% = 13.23). Similarly, CHMSGM showed a lower normalized median absolute deviation (NMAD) from CHMALS (0.68 m) compared to CHMeATE (1.1 m). Our study revealed that image-based point clouds using SGM in the presence of high-resolution ALS-derived digital terrain model (DTM) provide comparable results with ALS data, while the performance of image-based point clouds using eATE is poorer than ALS for forest height estimation. The findings of this study provide a viable and cost-effective option for assessing height-related forest structural parameters. The proposed methodology can be usefully applied in all those countries where AP are updated on a regular basis and pre-existing historical ALS-derived DTMs are available.

Keywords: Forest Inventory, Canopy Height Model, Stereo Aerial Photographs, LiDAR, Semi-Global Matching (SGM), enhanced Automatic Terrain Extraction (eATE)

iForest 10 (1): 273-280 (2017) - doi: 10.3832/ifor2077-009
https://iforest.sisef.org/contents/?id=ifor2077-009

Short Communications: Biodiversity inventory of trees in a neotropical secondary forest after abandonment of shaded coffee plantation

Oliveira-Neto NE, Nascimento DR, Carvalho FA — 2017-02-23

Oliveira-Neto NE, Nascimento DR, Carvalho FA

BIODIVERSITY INVENTORY OF TREES IN A NEOTROPICAL SECONDARY FOREST AFTER ABANDONMENT OF SHADED COFFEE PLANTATION

Abstract: Tree structure and diversity of a secondary Atlantic Forest resulting from the abandonment (ca. 70 years) of a shaded coffee (Coffea arabica) plantation was studied in southeastern Brazil. All trees with DBH ≥ 5 cm (alive and dead) were measured in 25 plots of 20 × 20 m. Out of the 1926 sampled trees, 1837 were living trees belonging to 116 species. The most important species (importance value - IV) in the community were Euterpe edulis (22.9% - present in all plots) and Piptadenia gonoacantha (16.5%). Euterpe edulis is a typical palm tree of high importance value in mature forests, comprising 41.2% of individuals. The results show a more mature tree community in relation to other secondary forests with the same abandonment period in the region, with high richness and diversity of species, high basal area, and low dead tree density. In addition, several endangered species were recorded with high conservation value for the regional flora. The results also showed many typical characteristics of “novel ecosystems” discussed here in order to value these environments, still neglected due to strong environmental human alterations.

Keywords: Brazilian Atlantic Forest, Forest Succession, Novel Ecosystem, Agroforestry

iForest 10 (1): 303-308 (2017) - doi: 10.3832/ifor1901-009
https://iforest.sisef.org/contents/?id=ifor1901-009

Research Articles: Identification and allelochemical activity of phenolic compounds in extracts from the dominant plant species established in clear-cuts of Scots pine stands

Šežiene V, Baležentiene L, Maruška A — 2017-02-23

Šežiene V, Baležentiene L, Maruška A

IDENTIFICATION AND ALLELOCHEMICAL ACTIVITY OF PHENOLIC COMPOUNDS IN EXTRACTS FROM THE DOMINANT PLANT SPECIES ESTABLISHED IN CLEAR-CUTS OF SCOTS PINE STANDS

Abstract: Dominant plant species established in the understory of clear-cuts may have a strong biochemical influence on pine regeneration process, with important consequences for reforestation management. We evaluated and compared the total phenolic content and the allelopathic activity of acqueous extracts from both roots and shoots of dominant plant species established in 1-yr-old and 2-yr-old clear-cuts of Scots pine (Pinus sylvestris L.) stands in Lituania. The highest total content of phenolic compounds was detected in the lingonberry (Vaccinium vitis-idaea L.) shoots from 1-yr-old and 2-yr-old clear-cuts, as well as in the common heather (Calluna vulgaris [L.[ Hull) shoots from 1-yr-old clear-cuts. High-performance liquid chromatography (HPLC) was used to identify and quantify the allelochemicals present in the active fraction to determine their possible role in allelopathy. The highest variety and content of phenolic compounds were observed in shoot extracts of the dominant species from both 1-yr-old and 2-yr-old clear-cuts. Scots pine seed germination and seedling growth were significantly and negatively correlated with ρ-coumaric acid and sinapic acid content, while Scots pine seedling growth was significantly and negatively correlated with ferulic, caffeic and hydroxycinnamic acids contents. The highest contents of these phenolic acids were determined in aqueous extracts of C. vulgaris from 1-yr-old clear-cuts and Rumex acetosella L. of 2-yr-old clear-cuts, which exerted a strong phytotoxicity on Scots pine seed germination. Moreover, morphometric parameters of Scots pine seedlings were most sensitive to aqueous extracts of V. vitis-idaea shoots from both 1-yr-old and 2-yr-old clear-cuts and R. acetosella shoots from 2-yr-old clear-cuts.

Keywords: Phenolics Identification, Allelopathy, Dominant Species, Germination

iForest 10 (1): 309-314 (2017) - doi: 10.3832/ifor1791-009
https://iforest.sisef.org/contents/?id=ifor1791-009

Research Articles: Comparing land use registry and sample based inventory to estimate forest area in Podlaskie, Poland

Jablonski M, Korhonen KT, Budniak P, Mionskowski M, Zajaczkowski G, Sućko K — 2017-02-23

Jablonski M, Korhonen KT, Budniak P, Mionskowski M, Zajaczkowski G, Sućko K

COMPARING LAND USE REGISTRY AND SAMPLE BASED INVENTORY TO ESTIMATE FOREST AREA IN PODLASKIE, POLAND

Abstract: The Land and Property Register (LPR) of Poland contains information on land use for the entire country. Additionally, a sample-based National Forest Inventory (NFI) provides statistical data for forest areas and detailed information on numerous forest parameters. However, until 2014 NFI plots were established only on areas classified as forest in the LPR. In this article, we present results of an estimation of forest area by extending the NFI measurements on all theoretical points in a grid, and compare the results with LPR information for one province (the Podlaskie voivodeship). At each point, we assess land use with recent aerial photographs and verify the ambiguous points in the field. Forest area in Poland is increasing due to afforestation and natural expansion of forest. Delays in the updating process of the LPR, and unwillingness of the owners to agree to reclassification of their land, have led to an underestimation of overall forest area. Our results demonstrate that forest area estimates made by the improved NFI are higher than those based upon the LPR. The modified NFI may be an appropriate tool for monitoring forest area changes in Poland.

Keywords: Land Cover, Afforestation, Natural Expansion of Trees, Land and Property Register, National Forest Inventory

iForest 10 (1): 315-321 (2017) - doi: 10.3832/ifor2078-009
https://iforest.sisef.org/contents/?id=ifor2078-009

Review Papers: Use of canopy gap openings to restore coniferous stands in Mediterranean environment

Muscolo A, Settineri G, Bagnato S, Mercurio R, Sidari M — 2017-02-23

Muscolo A, Settineri G, Bagnato S, Mercurio R, Sidari M

USE OF CANOPY GAP OPENINGS TO RESTORE CONIFEROUS STANDS IN MEDITERRANEAN ENVIRONMENT

Abstract: In Mediterranean regions, climate change increasingly affect tree species distributions. Conifer forests under continuing disturbance show a more rapid shift to dominance by beech and other temperate broadleaves. Thus, there is an urgent need to conserve coniferous vegetation to avoid local extinction. Gap opening has profound effects on the structure and dynamics of most forests and may represent a sustainable way to restore coniferous ecosystems in Mediterranean habitats. What kind of artificial canopy opening is the most sustainable and effective means for restoring coniferous ecosystem functions? We explored the efficacy of artificial gaps in regeneration and dynamics of coniferous in Mediterranean environment. We examined how regeneration of different tree species is associated with soil environmental conditions and how gaps of different sizes influence the ecology and management of Mediterranean forest. Specifically, we analyzed gap disturbance in silver fir and black pine stands, as they dominate central and southern Italian forests. We demonstrated a specificity between gap size and coniferous species regeneration, indicating that small gaps (about 200 m2) favor silver fir regeneration, while black pine, depending on its subspecies, regenerates both in small and medium gaps (about 500 m2). Further, we found that gap characteristics (age and shape) and suitable substrate availability are the primary factors affecting seedling establishment. Our results provide functional information to design a silvicultural system useful to manage the natural regeneration of Mediterranean forest minimizing the environmental and visual impact.

Keywords: Biodiversity, Gap Cutting, Gap Dynamic, Forest Conservation, Forest Restoration

iForest 10 (1): 322-327 (2017) - doi: 10.3832/ifor1983-009
https://iforest.sisef.org/contents/?id=ifor1983-009

Research Articles: Analysis of dust exposure during chainsaw forest operations

Marchi E, Neri F, Cambi M, Laschi A, Foderi C, Sciarra G, Fabiano F — 2017-02-23

Marchi E, Neri F, Cambi M, Laschi A, Foderi C, Sciarra G, Fabiano F

ANALYSIS OF DUST EXPOSURE DURING CHAINSAW FOREST OPERATIONS

Abstract: In 1999, the European Union proclaimed hardwood dust carcinogenic based on the classification of the International Agency for Research on Cancer (IARC) issued in 1995. The operational exposure limit (OEL) for inhalable wood dust has been set to 5 mg m-3 by EU directives, though in different countries the OEL ranges from 1 to 5 mg m-3. The objective of this study was to determine the exposure to wood dust of forest workers in chainsaw cutting and processing and suggest possible countermeasures. The study took into consideration different silvicultural treatments (coppice clear cut, conifer thinning, conifer pruning, and sanitary cut) and chainsaw fuel (normal two-stroke gasoline mix and two alkylate fuels). All the forest operations were carried out in forests located in Central Italy, on the Apennine mountain range. During the tests, 100 samples were collected by means of personal SKC Button Sampler (one sample per worker per day). The results showed that exposure to wood dust varied widely with forest operation type, while no significant difference were found for different type of chainsaw fuel. The average wood dust concentration was about 1.5 mg m-3 for all operations except coppicing, which showed a mean level of about 2.1 mg m-3. About 93% of the samples showed a concentration lower than 3 mg m-3, and in only two samples (one in conifer pruning and one in clear cut in coppice), the concentration was slightly higher than 5 mg m-3.

Keywords: Forest Operation, Chainsaw, Inhalable Wood Dust, Wood Dust Exposure, Cancer

iForest 10 (1): 341-347 (2017) - doi: 10.3832/ifor2123-009
https://iforest.sisef.org/contents/?id=ifor2123-009

Technical Reports: Detecting tree water deficit by very low altitude remote sensing

Martin H, Labbé S, Baldet P, Archaux F, Philippe G — 2017-02-11

Martin H, Labbé S, Baldet P, Archaux F, Philippe G

DETECTING TREE WATER DEFICIT BY VERY LOW ALTITUDE REMOTE SENSING

Abstract: In a context of climate change and expected increasing drought frequency, it is important to select tree species adapted to water deficit. Experimentation in tree nurseries makes it possible to control for various factors such as water supply. We analyzed the spectral responses for two genetic varieties of Douglas fir sapling exposed to different levels of water deficit. Our results show that the mean NDVI derived from remote sensing at very low altitudes clearly differentiated stress levels while genetic varieties were partially distinguished.

Keywords: Very Low Altitude Remote Sensing, Water Deficit, Variety, Douglas Fir

iForest 10 (1): 215-219 (2017) - doi: 10.3832/ifor1690-009
https://iforest.sisef.org/contents/?id=ifor1690-009

Research Articles: Combined effects of short-day treatment and fall fertilization on growth, nutrient status, and spring bud break of Pinus tabulaeformis seedlings

Pan J, Jacobs DF, Li G — 2017-02-11

Pan J, Jacobs DF, Li G

COMBINED EFFECTS OF SHORT-DAY TREATMENT AND FALL FERTILIZATION ON GROWTH, NUTRIENT STATUS, AND SPRING BUD BREAK OF PINUS TABULAEFORMIS SEEDLINGS

Abstract: Although effects of short-day treatment and fall fertilization on seedling development have been studied independently, their combined influences are not well elucidated. We explored growth, nutrient concentration, and spring bud break of Chinese pine (Pinus tabulaeformis Carr.) seedlings exposed to two photoperiod treatments (short-day consisting of 3 weeks of 18-hr nights in late summer and ambient day length) and three rates of fall N fertilization (0, 12 and 24 mg N per seedling). Seedlings were assessed before fall fertilization and at the end of the growing season. Bud break timing was evaluated the following spring. Increased foliar P concentration concurrent with reduced root P and K concentration occurred in short-day treated seedlings at the conclusion of photoperiod treatment. By the end of the growing season, short-day treatment resulted in greater N and P concentration in the stems, and P concentration in the foliage. It also induced smaller foliage and stem dry mass in both stages. Fall fertilization consistently enhanced tissue N concentration, but interaction effects with short-day treatment were generally non-significant. Short-day treatment curtailed shoot growth, induced terminal bud set, and hastened spring bud break (by only one day) for this mid-latitude seed source (41° N). Thus, short-day treatment or fall fertilization each promoted an increased nutrient concentration, while having only a minor effect on spring bud break.

Keywords: Photoperiod, Autumn Fertilization, Nutrient Loading, Bud Break

iForest 10 (1): 242-249 (2017) - doi: 10.3832/ifor2178-009
https://iforest.sisef.org/contents/?id=ifor2178-009

Research Articles: Comparison of range-wide chloroplast microsatellite and needle trait variation patterns in Pinus mugo Turra (dwarf mountain pine)

Zukowska WB, Boratynska K, Wachowiak W — 2017-02-11

Zukowska WB, Boratynska K, Wachowiak W

COMPARISON OF RANGE-WIDE CHLOROPLAST MICROSATELLITE AND NEEDLE TRAIT VARIATION PATTERNS IN PINUS MUGO TURRA (DWARF MOUNTAIN PINE)

Abstract: In this study, range-wide genetic variation was analysed in 553 Pinus mugo Turra (dwarf mountain pine) individuals from 21 locations using 11 chloroplast microsatellites. Our main goal was to assess the spatial distribution of neutral genetic variation. We also used data from a previous study on the morphological variation of needles from 18 stands of P. mugo. In total, 22 needle characteristics were reanalysed and compared to microsatellite data to describe the distribution of morphological variation in the context of neutral genetic variation. We hypothesised that the chloroplast microsatellite and needle trait variation patterns would not entirely overlap. The results indicate the recent divergence of P. mugo populations derived from a formerly larger distribution. We identified 4 genetic and 3 morphological clusters whose spatial distribution overlapped only to some extent. The distribution of genetic variation showed a south-north pattern with signs of admixture in the Alps and Carpathians. Two south-westernmost stands from Italy were evidently isolated from the others. In contrast, morphological variation tended to display a west-east pattern. A separate group based on needle traits was formed mostly by eastern stands and was not observed by microsatellite analysis. In addition, a few needle characteristics significantly correlated with longitude and climate variables. These findings suggest that eastern populations of P. mugo may be of different origin and/or that some needle characteristics may be adaptively important in these locations. The potential roles of past demographic events, phenotypic plasticity and local adaptation in shaping the patterns of genetic and morphological variation in P. mugo are discussed.

Keywords: Adaptation, cpSSRs, Genetic Diversity, Morphological Variation, Neutral Genetic Markers, Phenotypic Plasticity

iForest 10 (1): 250-258 (2017) - doi: 10.3832/ifor1860-009
https://iforest.sisef.org/contents/?id=ifor1860-009

Research Articles: Modelling dasometric attributes of mixed and uneven-aged forests using Landsat-8 OLI spectral data in the Sierra Madre Occidental, Mexico

2017-02-11

López-Sánchez CA, García-Ramírez P, Resl R, Hernández-Díaz JC, López-Serrano PM, Wehenkel C

MODELLING DASOMETRIC ATTRIBUTES OF MIXED AND UNEVEN-AGED FORESTS USING LANDSAT-8 OLI SPECTRAL DATA IN THE SIERRA MADRE OCCIDENTAL, MEXICO

Abstract: Remote sensors can be used as a robust and effective means of monitoring isolated or inaccessible forest sites. In the present study, the multivariate adaptive regression splines (MARS) technique was successfully applied to remotely sensed data collected by the Landsat-8 satellite to estimate mean diameter at breast height (R2 = 0.73), mean crown cover (R2 = 0.55), mean volume (R2 = 0.57) and total volume per plot (R2 = 0.41) in the forest monitoring sites. However, the spectral data yielded poor estimates of tree number per plot (R2 = 0.22), the mean height (R2 = 0.25) and the mean diameter at base (R2 = 0.38). Seven spectral bands (band 1 to band 7), six vegetation indexes and other derived parameters (NDVI, SAVI, LAI, FPAR. ALB and ASR) and eight terrain variables derived from the digital elevation model (elevation, slope, aspect, plan curvature, profile curvature, transformed aspect, terrain shape index and wetness index) were used as predictors in the fitted models. To prevent over-parameterization only some of the predictor variables considered were included in each model. The results indicate the MARS technique is potentially suitable for estimating dasometric variables from using spectral data obtained by the Landsat-8 OLI sensor.

Keywords: Multivariate Adaptive Regression Splines, Mixed Forest, Uneven-aged Forest, Stand Variables, Remote Sensing, Terrain Features

iForest 10 (1): 288-295 (2017) - doi: 10.3832/ifor1891-009
https://iforest.sisef.org/contents/?id=ifor1891-009

Research Articles: A rapid method for estimating the median diameter of the stem profile of Norway spruce (Picea abies Karst) trees

Vasilescu MM, Teresneu CC, Dinulica F — 2017-02-11

Vasilescu MM, Teresneu CC, Dinulica F

A RAPID METHOD FOR ESTIMATING THE MEDIAN DIAMETER OF THE STEM PROFILE OF NORWAY SPRUCE (PICEA ABIES KARST) TREES

Abstract: The median diameter of a longitudinal section of the stem may be used to determine the stem volume. However, to calculate stem volume, many measurements of diameter at different heights along the stem are required. Therefore, this approach is not generally applied because time-consuming and expensive. Here, we propose a novel, more rapid method to obtain median diameter using the area of the stem profile. A total of 218 height/diameter classes from more than 5000 spruce trees (Picea abies Karst.) were used to compute the median diameter using the classical method. In parallel, a regression model to assess the median diameter was developed. The strongest predictor of the median diameter for the stem profile was the diameter at breast height (R2 = 0.9985). Statistical analysis revealed that the height of the median diameter on the stem profile was 0.3 × H (tree height). The model was verified on standing and felled trees, revealing that differences between classical computations and the proposed model were less than 2% in most cases (86.24% of trees). The median diameter of the stem profile provides valuable information on stand architecture that could help in advancing our understanding on the mechanical stability of Norway spruce trees (i.e., delineating breakage point), growth model predictions, and competition among trees.

Keywords: Forest Mensuration, Median Diameter, Stem, Structure, Tree Stability

iForest 10 (1): 328-333 (2017) - doi: 10.3832/ifor1945-009
https://iforest.sisef.org/contents/?id=ifor1945-009

Research Articles: Adaptive response of Pinus monticola driven by positive selection upon resistance gene analogs (RGAs) of the TIR-NBS-LRR subfamily

2017-02-02

Zambounis A, Avramidou E, Papadima A, Tsaftaris A, Arzimanoglou I, Barbas E, Madesis P, Aravanopoulos FA

ADAPTIVE RESPONSE OF PINUS MONTICOLA DRIVEN BY POSITIVE SELECTION UPON RESISTANCE GENE ANALOGS (RGAS) OF THE TIR-NBS-LRR SUBFAMILY

Abstract: Western white pine (Pinus monticola Dougl.) is an important forest tree species, which is intensively plagued by the fungus Cronartium ribicola. Resistance gene analogs (RGAs) are the most highly abundant class of potential resistance (R) genes sharing greatly conserved domains and structures. Hence RGAs are crucial components for disease resistance breeding programs on P. monticola serving as useful functional markers. A total of 33 P. monticola RGAs gene homologues were mined from GenBank, encoding for R gene members of the TIR-NBS-LRR subfamily. The existence of positive selection acting upon RGAs was determined using a series of maximum likelihood analyses. Robust evidence of positive selection was showed to be acting widely in three clades across RGA gene phylogeny, both on terminal and ancestral lineages. Furthermore, our analysis revealed that the majority of positively selected residues sites are localized widely across these RGAs sequences, putatively affecting the structures of their ligand-binding domains and offering novel specificities. These results may find immediate application in ongoing disease resistance breeding programs.

Keywords: Fungal Diseases, Genomics-assisted Breeding, Non-synonymous Nucleotide Substitution, Positive Selection, Resistance Gene Analogs (RGAs), White Pines

iForest 10 (1): 237-241 (2017) - doi: 10.3832/ifor2050-009
https://iforest.sisef.org/contents/?id=ifor2050-009

Commentaries & Perspectives: Comments to Loewe et al. - Growth of Stone pine (Pinus pinea L.) European provenances in central Chile

Agrimi M — 2017-02-02

Agrimi M

COMMENTS TO LOEWE ET AL. - GROWTH OF STONE PINE (PINUS PINEA L.) EUROPEAN PROVENANCES IN CENTRAL CHILE

Abstract: The author replies to the article by Loewe Muñoz et al. (2016), published on Aug 29, 2016 in iForest - Biogeosciences and Forestry, shortly commenting the choice of a Lombardy provenance of Pinus pinea L. used in the field trial experiment test at issue.

Keywords: Stone pine, Productivity, Growth, Provenances

iForest 10 (1): 353-354 (2017) - doi: 10.3832/ifor0078-010
https://iforest.sisef.org/contents/?id=ifor0078-010

Research Articles: Coping with spring frost-effects on polyamine metabolism of Scots pine seedlings

2017-01-27

Muilu-Mäkelä R, Vuosku J, Saarinen M, Hamberg L, Ruotsalainen S, Häggman H, Sarjala T

COPING WITH SPRING FROST-EFFECTS ON POLYAMINE METABOLISM OF SCOTS PINE SEEDLINGS

Abstract: Polyamines (PA) are ubiquitous polycations known to be involved in several phases of plant development as well as in tolerance to abiotic stresses. Phenols are complex secondary metabolites produced via the phenylpropanoid pathway that contain, e.g., cell wall compounds and antioxidants. Phenols are known to enhance chilling tolerance of plants. PA and phenolic pathways are connected via conjugation. In boreal coniferous forests spring frost has been considered to have severe effects on the survival of tree seedlings. Such effects are likely to increase in the future. The present study focuses on the role of PA and phenylpropanoid syntheses in the coping strategies of Scots pine exposed to cold temperatures during the vulnerable early seedling phase in late spring and early summer. We found that spring frost affects the expression of genes regulating PA metabolism and phenylpropanoid synthesis differently in above and below ground parts of the seedlings, whereas PA or phenol contents in tissues were not affected. The results suggest that Scots pine seedlings may not have time to develop metabolite level responses during a short period of freezing stress and, therefore, the originally different PA levels, especially in roots, may influence the tolerance of Scots pine seedlings to spring frost.

Keywords: Phenylpropanoids, Polyamines, Scots Pine, Spring Frost

iForest 10 (1): 227-236 (2017) - doi: 10.3832/ifor2003-009
https://iforest.sisef.org/contents/?id=ifor2003-009

Research Articles: Integrating area-based and individual tree detection approaches for estimating tree volume in plantation inventory using aerial image and airborne laser scanning data

Shinzato ET, Shimabukuro YE, Coops NC, Tompalski P, Gasparoto EA — 2016-12-15

Shinzato ET, Shimabukuro YE, Coops NC, Tompalski P, Gasparoto EA

INTEGRATING AREA-BASED AND INDIVIDUAL TREE DETECTION APPROACHES FOR ESTIMATING TREE VOLUME IN PLANTATION INVENTORY USING AERIAL IMAGE AND AIRBORNE LASER SCANNING DATA

Abstract: Remote sensing has been increasingly used to assist forest inventory. Airborne Laser Scanning (ALS) systems can accurately estimate tree height in forests, and are being combined with more traditional optical images that provide further details about the horizontal structure of forests. To predict forest attributes two main techniques are applied to process ALS data: the Area Based Approach (ABA), and the Individual Tree Detection (ITD). The first part of this study was focused on the effectiveness of integrating ALS data and aerial imagery to estimate the wood volume in Eucalyptus urograndis plantations using the ABA approach. To this aim, we analyzed three different approaches: (1) using only ALS points cloud metrics (RMSE = 6.84%); (2) using only the variables derived from aerial images (RMSE = 8.45%); and (3) the integration of both 1 and 2 (RMSE = 5.23%), which underestimated the true volume by 2.98%. To estimate individual tree volumes we first detected individual trees and corrected the density estimate for detecting mean difference, with an error of 0.37 trees per hectare and RMSE of 12.68%. Next, we downscaled the total volume prediction to single tree level. Our approach showed a better result of the overall volume in comparison with the traditional forest inventory. There is a remarkable advantage in using the Individual Tree Detection approach, as it allows for a spatial representation of the number of trees sampled, as well as their volume per unit area - an important metric in the management of forest resources.

Keywords: Forest Inventory, Airborne Laser Scanning, Treetop Detection, Eucalyptus Plantation, Area-based Approach, LiDAR

iForest 10 (1): 296-302 (2017) - doi: 10.3832/ifor1880-009
https://iforest.sisef.org/contents/?id=ifor1880-009

Research Articles: Effects of altitudinal gradients on leaf area index, soil microbial biomass C and microbial activity in a temperate mixed forest ecosystem of Northwestern Turkey

Bolat I, Öztürk M — 2016-12-15

Bolat I, Öztürk M

EFFECTS OF ALTITUDINAL GRADIENTS ON LEAF AREA INDEX, SOIL MICROBIAL BIOMASS C AND MICROBIAL ACTIVITY IN A TEMPERATE MIXED FOREST ECOSYSTEM OF NORTHWESTERN TURKEY

Abstract: A high leaf area index (LAI) can provide indications of high fertility, such as optimal health and productivity in forest ecosystem. Yet, studying the microbial biomass and inherent activity in any forest ecosystem may enable better understanding of the role of microorganisms in soil quality and nutrient cycling. This study was carried out in the western Black Sea region of Turkey with the aim to determine the influence of elevation on LAI, microbial biomass and activity in a mixed forest ecosystem. Marked differences in the LAI, light transmission, soil temperature, Corg/Ntotal ratio, and microbial properties were found at sites sampled at different elevations along an altitudinal gradient (i.e., 1200, 1300 and 1400 m a.s.l.). The LAI was statistically (P < 0.05) higher at 1300 (3.28 m2 m-2) and 1400 m (3.20 m2 m-2) elevations compared to 1200 m (2.84 m2 m-2) elevation, whereas the light transmission was statistically (P < 0.05) lower at 1300 and 1400 m elevations than that at 1200 m elevation. The amount of microbial biomass C at 1300 m (892.26 µg g-1) and 1400 m (725.99 µg g-1) elevations was significantly (P < 0.05) higher than that at 1200 m (650.84 µg g-1) elevation. Basal respiration did not vary significantly (P > 0.05) along the altitudinal gradient. An increase in respiration per unit biomass (i.e., increasing the metabolic quotient - qCO2) was also found in the sampling sites at 1200 m a.s.l. There was a positive relationship between the microbial biomass C and LAI (r = 0.612, P < 0.01) and negative relationship between the qCO2 and LAI (r = - 0.592, P < 0.01). Our results showed that the elevation gradient has a significant influence on the LAI, microbial biomass C and microbial activity in the forest stand type analyzed. A subdivision of the forest stand types into different sub-types according to their productivity and development is advisable and recommended for forest management and administration purposes.

Keywords: Basal Respiration, Bornmullerian Fir, Cmic/Corg Percentage, Metabolic Quotient (qCO2), Oriental Beech, Soil

iForest 10 (1): 334-340 (2017) - doi: 10.3832/ifor1974-009
https://iforest.sisef.org/contents/?id=ifor1974-009

Research Articles: Inter- and intra-annual patterns of seed rain in the black spruce stands of Quebec, Canada

Rossi S, Morin H, Gionest F, Laprise D — 2016-12-13

Rossi S, Morin H, Gionest F, Laprise D

INTER- AND INTRA-ANNUAL PATTERNS OF SEED RAIN IN THE BLACK SPRUCE STANDS OF QUEBEC, CANADA

Abstract: Divergent reproductive strategies of tree species generate differences in the dynamics of seed production and dispersion. The spatial and temporal variability in seed rain abundance and viability was monitored during the period 2000-2007 in four boreal stands in Quebec, Canada. The aim was to compare the inter- and intra-annual patterns of seed dispersal between species with diverging adaptive characteristics and reproductive strategies by testing the hypothesis that sympatric species can exhibit different patterns of seed dispersal according to specific ecological adaptations. The coefficient of variation (CV), representing the inter-annual variability in seed rain, was close to or higher than 1 in balsam fir (Abies balsamea [L.] P. Mill.) and white birch (Betula papyrifera Marsh.) and confirmed the mast seeding habit of the two species. In contrast, CV in black spruce (Picea mariana [Mill.] BSP) ranged between 0.24 and 0.54, indicating a more homogeneous inter-annual amount of seed dispersal because of its semiserotinous cones that preserve seeds for an indefinite period of time. The species showed divergent intra-annual patterns of seed dispersal. Most seed dispersal of the companion species was observed in September-November, while black spruce concentrated seed rain in spring, when the proportion of germinated seeds was higher. Boreal stands experience annual seed rains constituted by a gradual dispersal of seeds of different ages and originating from cones belonging to multiple cohorts. However, asynchronous seed rains in terms of quantity and quality can occur if companion species are associated to the dominant black spruce.

Keywords: Balsam Fir, Fire, Masting, Regeneration, Reproduction, Seed Viability, Serotiny, White Birch

iForest 10 (1): 189-195 (2017) - doi: 10.3832/ifor2145-009
https://iforest.sisef.org/contents/?id=ifor2145-009

Research Articles: Environmental Kuznets curve for deforestation: evidence using GMM estimation for OECD and non-OECD regions

Joshi P, Beck K — 2016-12-13

Joshi P, Beck K

ENVIRONMENTAL KUZNETS CURVE FOR DEFORESTATION: EVIDENCE USING GMM ESTIMATION FOR OECD AND NON-OECD REGIONS

Abstract: The depletion of the world’s forests in both tropical and temperate regions threatens to cause considerable environmental problems and hamper future economic development. However, some research has suggested that this deforestation might slow or reverse, exhibiting an Environmental Kuznets Curve (EKC). Yet previous studies investigating such an EKC have found mixed results. We therefore test for a deforestation EKC using an improved dataset from the World Development Indicators and an enhanced econometric technique Arellano-Bover/Blundell-Bond Generalized Method of Moments (GMM) estimator. We compare OECD countries with the non-OECD regions of Latin America, Asia, and Africa to determine how various factors like economic growth, population, trade, urbanization, agricultural land conversion, and cereal yield impact deforestation rates. The results show that the OECD countries have an N-shaped curve whereas only the African region experiences an income-based EKC pattern. Population growth tends to create more deforestation as does conversion to agricultural lands. More trade openness and greater urbanization impact the regions differently, but only the OECD countries have less deforestation due to better cereal yields.

Keywords: Environmental Kuznets Curve, Deforestation, GMM, OECD, Non-OECD

iForest 10 (1): 196-203 (2017) - doi: 10.3832/ifor2066-009
https://iforest.sisef.org/contents/?id=ifor2066-009

Research Articles: Fertilisation of Quercus seedlings inoculated with Tuber melanosporum: effects on growth and mycorrhization of two host species and two inoculation methods

Garcia-Barreda S, Molina-Grau S, Reyna S — 2016-12-13

Garcia-Barreda S, Molina-Grau S, Reyna S

FERTILISATION OF QUERCUS SEEDLINGS INOCULATED WITH TUBER MELANOSPORUM: EFFECTS ON GROWTH AND MYCORRHIZATION OF TWO HOST SPECIES AND TWO INOCULATION METHODS

Abstract: Modern truffle cultivation is based on use of inoculated seedlings, which should exhibit highly colonised roots as well as a vegetative quality enhancing field plant performance. However, poor shoot and fine root growth has been a frequent issue in inoculated Quercus seedlings production. Fertilisation is a common solution in forest nurseries, but high fertilisation levels have been found to inhibit the formation of ectomycorrhizas of many fungal species. The influence of slow-release fertilisation (52 mg N, 26 mg P and 36 mg K per seedling) on growth and ectomycorrhizal status of Tuber melanosporum-inoculated seedlings was evaluated. Host species Quercus ilex and Quercus faginea and inoculation methods involving root-dipping and root-powdering were tested. Fertilisation increased weight of both host species without significant detrimental effects on ectomycorrhizal colonisation, showing that it can be effectively used in inoculated seedlings production. Both host species showed similar response to fertilisation. The inoculation method affected seedling weight and ectomycorrhizal status, suggesting that some inoculant carriers are able to damage Quercus development and T. melanosporum colonisation. The study provided an important basis for fine-tuning the use of fertilisers in truffle-inoculated seedling production.

Keywords: Fertilisation, Seedling, Nursery, Ectomycorrhizal, Inoculation

iForest 10 (1): 267-272 (2017) - doi: 10.3832/ifor2096-009
https://iforest.sisef.org/contents/?id=ifor2096-009

Research Articles: Response of artificially defoliated Betula pendula seedlings to additional soil nutrient supply

Araminiene V, Varnagiryte-Kabašinskiene I, Stakenas V — 2016-12-13

Araminiene V, Varnagiryte-Kabašinskiene I, Stakenas V

RESPONSE OF ARTIFICIALLY DEFOLIATED BETULA PENDULA SEEDLINGS TO ADDITIONAL SOIL NUTRIENT SUPPLY

Abstract: The impact of leaf damage on the growth of young silver birch seedlings with and without additional nutrient supply was investigated by simulating leaf-insect damage and applying different levels (25%, 50% and 75%) of artificial defoliation. Based on field-practical and cost-effective methods, we determined how fertilization practices compensate for foliage loss, and the combined effect on silver birch seedling growth. The mineral fertilizers applied to the 25-75%-defoliated silver birch seedlings reduced the growth in aboveground biomass compared to the fertilized but undamaged seedlings. Our results showed that when the birch seedlings received more nutrients they did not compensate for the loss of foliar mass. However, the seedlings loosing part of their foliar mass and receiving no additional fertilizers did compensate for the foliage loss and their root growth was not weakened, using soil nutrients more effectively. Mineral fertilization up to optimal nutritional balance could be a beneficial tool for increasing growth rate and biomass accumulation in the short-term period. However, our study demonstrated that additional fertilization does not necessarily lead to growth compensation of partly defoliated young birch trees.

Keywords: Betula pendula, Artificial Defoliation, Fertilization, Aboveground Biomass, Photosynthesis

iForest 10 (1): 281-287 (2017) - doi: 10.3832/ifor2086-009
https://iforest.sisef.org/contents/?id=ifor2086-009

Research Articles: Influence of soil and topography on defoliation intensity during an extended outbreak of the common pine sawfly (Diprion pini L.)

Kosunen M, Kantola T, Starr M, Blomqvist M, Talvitie M, Lyytikäinen-Saarenmaa P — 2016-11-19

Kosunen M, Kantola T, Starr M, Blomqvist M, Talvitie M, Lyytikäinen-Saarenmaa P

INFLUENCE OF SOIL AND TOPOGRAPHY ON DEFOLIATION INTENSITY DURING AN EXTENDED OUTBREAK OF THE COMMON PINE SAWFLY (DIPRION PINI L.)

Abstract: Insect herbivore disturbances are likely to intensify as a consequence of climate change. In Finland, outbreaks of the common pine sawfly (Diprion pini L.), which feeds on Scots pine (Pinus sylvestris L.) needles, and resulting damage to forests have already increased. Although drivers of sawfly outbreak dynamics have been investigated, the effects of topography and soil fertility have not been fully elucidated. We studied the effect of elevation, slope and soil properties (carbon and nitrogen contents, C/N ratio, pH, texture and horizon thicknesses) on the defoliation intensity of 28 plots (227-531 m2), located in a 34.5 km2 forested area in eastern Finland suffering from an extended outbreak of D. pini. Plot elevation and slope (relative relief 35 m, maximum elevation 200 m a.s.l.) were derived from a digital elevation model and the soil properties from samples of the humus layer (Of+Oh), (Ah+)E and B horizons of podzol profiles. Defoliation was greater on the more fertile and flatter sites than on less fertile and steeper sites, but independent of elevation. The soil property most strongly correlated to plot mean defoliation was the C/N ratio of the humus layer (Spearman’s ρ = -0.68). However, logistic modelling showed that the thickness of the (Ah+)E-horizon had the highest classification accuracy in predicting the probability of a plot having moderate to severe (>20%) defoliation. Our study showed that forest damage caused by D. pini was related to topography and soil fertility. Taking these factors into account could help in understanding the population dynamics of D. pini, in modeling of insect outbreaks and in forest management planning.

Keywords: C/N Balance, Defoliation, Pine Sawfly, Soil, Topography

iForest 10 (1): 164-171 (2017) - doi: 10.3832/ifor2069-009
https://iforest.sisef.org/contents/?id=ifor2069-009

Research Articles: Terrestrial laser scanning as a tool for assessing tree growth

Sheppard J, Morhart C, Hackenberg J, Spiecker H — 2016-11-19

Sheppard J, Morhart C, Hackenberg J, Spiecker H

TERRESTRIAL LASER SCANNING AS A TOOL FOR ASSESSING TREE GROWTH

Abstract: Terrestrial laser scanning (TLS) technology is a powerful tool for assessing tree growth based on time series analysis, as it allows a level of scrutiny not achievable using established destructive techniques. We applied TLS technology to 21 wild cherry trees grown in a research plot near Breisach (southern Germany) in order to build quantitative structure models (QSMs) for each tree. Scans were carried out over three subsequent years (2012-2014), so that three QSMs per each tree were constructed. Using the above approach, we were able to assess the annual growth of the individual wild cherry trees in terms of diameter and height, stem and branch volume, and the merchantable timber fraction. In addition, the growth of single branches of sample trees was detected and quantified. The availability of QSMs based on TLS-derived data allowed the accurate determination of crown length and width, as well as the volume reduction as the result of the tree pruning applied after the first scan (2012). The aboveground biomass (AGB) was assessed for each tree based on the QSM-derived volume and published wood density values for wild cherry, and then compared with AGB values estimated with standard allometric methods, obtaining a very high correlation (r2adj = 0.941). We concluded that the proposed approach is an effective non-destructive technique to accurately assess the increase of tree biomass, and discuss its future application in the forestry sector.

Keywords: TLS, Time Series Analysis, Prunus avium L., Wild Cherry, Simpletree, Quantitative Structure Models

iForest 10 (1): 172-179 (2017) - doi: 10.3832/ifor2138-009
https://iforest.sisef.org/contents/?id=ifor2138-009

Research Articles: Potential for utilization of wood ash on coastal arenosols with limited buffer capacity in KwaZulu-Natal and its effect on eucalypt stand nutrition and growth

Scheepers GP, du Toit B — 2016-11-19

Scheepers GP, du Toit B

POTENTIAL FOR UTILIZATION OF WOOD ASH ON COASTAL ARENOSOLS WITH LIMITED BUFFER CAPACITY IN KWAZULU-NATAL AND ITS EFFECT ON EUCALYPT STAND NUTRITION AND GROWTH

Abstract: A field trial was established to test the effects of various wood ash and fertilizer application rates on the nutrition and early growth of a clonal Eucalyptus grandis × urophylla stand near Richards Bay, KwaZulu-Natal province, South Africa. The trial consisted of wood ash treatments of 0, 0.3, 0.6 and 1.2 t ha-1, combined with fertilizer treatments of no fertilizer (control), 150 g tree-1 of conventional ammonium sulphate fertilizer or 320 g tree-1 of controlled release fertilizer mixture containing N, P and a balanced suite of several plant nutrients. The experiment was conducted on a young sandy soil of aeolian origin with a very low buffer capacity. Ash application rates were chosen after a pilot study was conducted to test the effect of CaCO3 on the soil reaction. At 4 and 8 months after treatment, soil heavy metal concentrations for cadmium (Cd), mercury (Hg), chromium (Cr) and lead (Pb) levels were substantially lower than toxic levels. Foliar heavy metal concentrations (for the same elements) were less than 1mg kg-1 at both time intervals. The wood ash induced a temporary liming effect up to 8 months after application. Foliar nutrient assessments revealed sub-optimal nutrient concentrations for phosphorous (P), potassium (K) and zinc (Zn) at 4 months and K at 8 months of age. The positive growth responses (expressed as a biomass index) at 8 months, ranged between 13% and 683% relative to the untreated control. At 21 months, the growth response to ash and fertilizer combinations ranged from -0.5% to 50% relative to the control. This research demonstrated that 1.2 t ha-1 of wood ash can safely be disposed of on a typical, poorly buffered Zululand coastal sand with little environmental risk and minimal growth suppression, provided that it is balanced with an appropriate NPS plus trace element fertilizer mixture.

Keywords: Wood Ash, Eucalyptus grandis × urophylla, Stand Nutrition, Entisol, Heavy Metals, Fertilizer

iForest 10 (1): 180-188 (2017) - doi: 10.3832/ifor2146-009
https://iforest.sisef.org/contents/?id=ifor2146-009

Short Communications: Determining Pleiades satellite data capability for tree diversity modeling

Akbari H, Kalbi S — 2016-11-19

Akbari H, Kalbi S

DETERMINING PLEIADES SATELLITE DATA CAPABILITY FOR TREE DIVERSITY MODELING

Abstract: Modeling of the spatial distribution of tree species based on survey data has recently been applied to conservation planning. Numerous methods have been developed for building species habitat suitability models. The aim of this study was to investigate the suitability of Pleiades satellite data for modeling tree species diversity of Hyrcanian forests in northern Iran (Mazandaran Province). One-hundred sample plots were established over an area of 2.600 ha and surveyed for tree diversity, and the Simpson’s index (D), Shannon’s index (H’) and the reciprocal of Simpson’s index (1/D) were calculated for each plot. Spectral variables and several parameters derived by texture analysis were obtained from multispectral images of the study area and used as predictors of tree diversity of sample plots. Two different methods, including generalized additive models (GAMs) and multivariate adaptive regression splines (MARS), were used for modeling. The results revealed a fairly good prediction of plot tree diversity obtained using the developed models (adj-R2 = 0.542-0.731). Shannon’s H’ and Simpson’s 1/D indices were more accurately predicted using GAM-based methods, while MARS models were more suitable for predicting Simpson’s D. We concluded that Pleiades satellite data can be conveniently used for estimating, assessing and monitoring tree species diversity in the mixed hardwood Hyrcanian forest of northern Iran.

Keywords: Pleiades, Tree Species Diversity, Modeling, Darabkola Forest

iForest 10 (1): 348-352 (2017) - doi: 10.3832/ifor1884-009
https://iforest.sisef.org/contents/?id=ifor1884-009

Research Articles: Below- and above-ground biomass, structure and patterns in ancient lowland coppices

Vrška T, Janík D, Pálková M, Adam D, Trochta J — 2016-11-06

Vrška T, Janík D, Pálková M, Adam D, Trochta J

BELOW- AND ABOVE-GROUND BIOMASS, STRUCTURE AND PATTERNS IN ANCIENT LOWLAND COPPICES

Abstract: Ancient coppice woods are areas that reflect long-term human influence and contain high species biodiversity. In this type of forest we aimed to: (i) analyze the below- and above ground biomass of stools and estimate the age of largest stool; (ii) define a “zone of interference” for coppices; (iii) describe and classify variability in the shape and size of coppice stools; (iv) define the specific characteristics of the spatial distribution of stems and stools. The study was conducted in the Podyjí National Park, Czech Republic, where two old oak coppice stands were fully stem mapped: Lipina (3.90 ha) and Šobes (2.37 ha). Cores were processed using TimeTable and PAST4. Below- and above-ground biomass of the largest stools was computed using the data from terrestrial laser scanner. Tree zones of influence were analyzed with V-Late landscape analysis tools using Shape Index. The pair correlation function and L function were used to describe the spatial patterns of trees with DBH ≥ 7 cm, and the null model of Complete Spatial Randomness and Matérn cluster process were tested. For a modeled old stool, we estimated a ratio of 2:1 for above/below ground volume with no reduction of below ground biomass regarding the hollow roots. The age of the largest stool was estimated 825 ± 145 (SE) years. An “Inner Zone of Influence” was defined, with a total area covering 323 m2 ha-1. The median area of this zone in both plots was 0.40 m2 for all trees, 0.23 m2 for singles and 0.87 m2 for stools. The Matérn cluster process was successfully fitted to our empirical data. In this model, the mean cluster radius ranged between 1.9 to 2.1 m and mean number of points per cluster was 1.7 and 1.9. The most prevalent characteristics of these ancient oak coppices were their compact shape and clustered spatial distribution up to 10 m.

Keywords: Oak, Stools, Spatial Patterns, Root System, Terrestrial Laser Scanning, Ancient Coppices

iForest 10 (1): 23-31 (2017) - doi: 10.3832/ifor1839-009
https://iforest.sisef.org/contents/?id=ifor1839-009

Research Articles: Quantitative simulation of C budgets in a forest in Heilongjiang province, China

Wang B, Li M, Fan W, Zhang F — 2016-11-06

Wang B, Li M, Fan W, Zhang F

QUANTITATIVE SIMULATION OF C BUDGETS IN A FOREST IN HEILONGJIANG PROVINCE, CHINA

Abstract: Recently, forest carbon (C) budgets have been significantly affected by climate variability, nitrogen (N) deposition, an increasing global atmospheric CO2 concentration, and disturbances (i.e., harvests, fires, and insect infestations). In this study, we quantitatively simulated the annual carbon balance of forests in Heilongjiang, China, from 1901 to 2013 using the Integrated Terrestrial Ecosystem Carbon (InTEC) model, which integrated the effects of nondisturbance (i.e., atmospheric CO2 concentration, N deposition, and climate variability) and disturbance factors. The average net primary production (NPP) of Heilongjiang was 284 g C m-2 a-1 in 1901 and increased in 1950 to 339 g C m-2 a-1; a rapid increase occurred after 1980, with an increase of 48% in 2013 compared with the NPP in 1901. The average NPP of the entire Heilongjiang region increased significantly and became more stable in 2013. However, the NPP in the northern region of the Xiaoxing’an Mountains was lower than that in the other regions. The fluctuation in average net ecosystem production (NEP) was relatively large because Heilongjiang was a carbon source for many years before the 1930s and again in the early 21st century, due to serious disturbances and intensified human activities. In recent years, NEP began to increase again, and in 2013 the forests became a large carbon sink (188 g C m-2 a-1). The spatial distribution of the average NEP was similar to that of NPP, though the largest increment in the average NEP from 1901 to 2013 was in the Changbai Mountains.

Keywords: InTEC Model, NPP, NEP, C Budgets, Heilongjiang

iForest 10 (1): 128-135 (2017) - doi: 10.3832/ifor1918-009
https://iforest.sisef.org/contents/?id=ifor1918-009

Research Articles: Hygroscopicity of the bark of selected forest tree species

Ilek A, Kucza J, Morkisz K — 2016-11-06

Ilek A, Kucza J, Morkisz K

HYGROSCOPICITY OF THE BARK OF SELECTED FOREST TREE SPECIES

Abstract: As the outer layer of trees and shrubs, bark is exposed to the direct action of atmospheric conditions and reacts to changes in relative air humidity. This study focuses on the actual hygroscopicity of the bark, regarded as a component of the total bark retention capability. The main research aims were to: (1) determine the physical properties (specific density, bulk density, total porosity), actual hygroscopicity and maximum water storage capacity of the stem bark at breast height (1.3 m) of eight forest tree species; (2) assess the relationship between bark actual hygroscopicity and its physical properties; (3) determine the share of the actual hygroscopicity of bark in its maximum water storage capacity. Significant differences were observed among the different species considered as a consequence of the variation in physical properties of their bark. Actual hygroscopicity of bark (expressed in balance units), i.e., the maximum water amount that can be absorbed from saturated air by the outer bark layer, showed a significant relationship with bark physical properties. Depending on tree species, actual hygroscopicity may constitute from 10 to 30% of the maximum water storage capacity of bark.

Keywords: Forest Hydrology, Forest Tree Bark, Bark Actual Hygroscopicity, Bark Water Storage Capacity

iForest 10 (1): 220-226 (2017) - doi: 10.3832/ifor1979-009
https://iforest.sisef.org/contents/?id=ifor1979-009

Research Articles: Wildland fire typologies and extreme temperatures in NE Spain

Cardil A, Merenciano D, Molina-Terrén DM — 2016-11-01

Cardil A, Merenciano D, Molina-Terrén DM

WILDLAND FIRE TYPOLOGIES AND EXTREME TEMPERATURES IN NE SPAIN

Abstract: Understanding instrumental factors dealing with the development of large wildland fires is a need. Fire spread typologies and extreme temperature days were studied in the 1978-2012 period in Aragón (NE Spain). Temperature was examined at 850 hPa to characterize the low troposphere state and wildfires were grouped in three fire spread typologies: convective fires, wind-driven fires and topography-driven fires. The analysis of wildland fire propagation typologies revealed that convective fires burned the majority of total area burned, resulting in the larger and the most closely typology related to high temperature days (HTDs). Drought Code (DC) correlation with HTDs and wildland fire size was weak.

Keywords: Wildland Fire, Fire Spread Patterns, Forestry, Heat Waves, Climate Change

iForest 10 (1): 9-14 (2017) - doi: 10.3832/ifor1939-009
https://iforest.sisef.org/contents/?id=ifor1939-009

Research Articles: Sap flow, leaf-level gas exchange and spectral responses to drought in Pinus sylvestris, Pinus pinea and Pinus halepensis

2016-11-01

Manzanera JA, Gómez-Garay A, Pintos B, Rodríguez-Rastrero M, Moreda E, Zazo J, Martínez-Falero E, García-Abril A

SAP FLOW, LEAF-LEVEL GAS EXCHANGE AND SPECTRAL RESPONSES TO DROUGHT IN PINUS SYLVESTRIS, PINUS PINEA AND PINUS HALEPENSIS

Abstract: In a climate change scenario, Mediterranean forest species such as pines may be endangered by rising temperatures and reduced precipitation, thus calling for studies on the transpiration and water balance in pines. In this paper, the response of young plants of Pinus sylvestris L., Pinus pinea L. and Pinus halepensis Mill. to different irrigation treatments has been studied. Significant differences were found in water potential, sap flow, leaf-level gas exchange and spectral variables. P. sylvestris had higher pre-dawn and midday water potentials, sap flow rates and leaf-level gas exchange rates compared to the other two species in well-watered conditions. Vapor pressure gradient correlated with stomatal conductance, net assimilation and transpiration, but the association between stomatal conductance and sap flow was weak. The environmental variables more strongly associated with sap flow were solar radiation and reference evapo-transpiration, especially in the well-watered plants, but those associations were weaker in the stressed plants. All three pine species showed the isohydric, drought-avoiding strategy common in the genus Pinus, maintaining relatively high water potentials in dry conditions. Nevertheless, P. halepensis showed a water-saving strategy, with a stomatal closure behavior under drought. Stomatal regulation was less strict in P. sylvestris, closer to a water-spending pattern, while P. pinea showed an intermediate behavior. Significant differences were recorded among species in spectral reflectance in the visible and infra-red regions. Photochemical Reflectance Index, Normalized Difference Vegetation Index and combinations of other ratios permitted the discrimination among the three pine species. These spectral variables showed association with sap flow rate, water potential and leaf-level gas exchange variables. Both cluster analysis and k-means classification discriminated Scots pine and Aleppo pine in two different groups. On the other hand, Stone pine showed differences in spectral behavior depending on the hydric status of the plants. Well-watered Stone pine plants had the same spectral behavior as Scots pine, while the plants subjected to drought stress were closer to Aleppo pine plants in spectral response. These findings may help to quantify the impacts of early and mid-summer water deficit on Mediterranean pines in future climate regimes.

Keywords: Carbon Assimilation, Aleppo Pine, Hydric Relations, Reflectance, Scots Pine, Stone Pine, Transpiration

iForest 10 (1): 204-214 (2017) - doi: 10.3832/ifor1748-009
https://iforest.sisef.org/contents/?id=ifor1748-009

Research Articles: Comparison of parametric and nonparametric methods for modeling height-diameter relationships

Adamec Z, Drápela K — 2016-10-19

Adamec Z, Drápela K

COMPARISON OF PARAMETRIC AND NONPARAMETRIC METHODS FOR MODELING HEIGHT-DIAMETER RELATIONSHIPS

Abstract: This paper focuses on the problem of regionalization of the height-diameter model at the stand level. To this purpose, we selected two different modeling techniques. As a parametric method, we chose a linear mixed effects model (LME) with calibrated conditional prediction, whose calibration was carried out on randomly selected trees either close to mean diameter or within three diameter intervals throughout the diameter range. As a nonparametric method, the technique of classification and regression trees (CART) was chosen. These two methods were also compared with the local model created by ordinary least squares regression. The results show that LME with calibrated conditional prediction based on measurements of height at three diameter intervals provided results very close to the local model, especially when six to nine trees are measured. We recommend this technique for the regionalization of the global model. The CART method provided worse results than LME, with the exception of parameters of the residual distribution. Nevertheless, the latter approach is very user-friendly, as the regression tree creation and especially its interpretation are relatively simple, and could be recommended when larger deviations are allowed.

Keywords: Calibration, Classification and Regression Trees, Hierarchical Structure, Linear Mixed Effects Model, Spatial Heterogeneity

iForest 10 (1): 1-8 (2017) - doi: 10.3832/ifor1928-009
https://iforest.sisef.org/contents/?id=ifor1928-009

Research Articles: Twenty years of conversion: from Scots pine plantations to oak dominated multifunctional forests

Vrška T, Ponikelský J, Pavlicová P, Janík D, Adam D — 2016-10-19

Vrška T, Ponikelský J, Pavlicová P, Janík D, Adam D

TWENTY YEARS OF CONVERSION: FROM SCOTS PINE PLANTATIONS TO OAK DOMINATED MULTIFUNCTIONAL FORESTS

Abstract: A conversion of previously even-aged pine-dominated forests to uneven-aged and multi-functional oak-dominated forests has been ongoing since 1993 in the Pyramida experimental forest (95 ha) situated in the buffer zone of Podyjí National Park, Czech Republic. Based on repeated surveys in 1992, 2003 and 2013, the conversion was assessed according to changes in: (i) the proportion of species; (ii) the distribution of DBH; (iii) the distribution of patches; and (iv) the distribution of forest types. The proportion of conifers decreased from 61.0% to 42.0%, and the proportion of broadleaved species increased accordingly. A sharp decline in the number of trees in the DBH class 70-109 mm was caused by the intense release of understorey broadleaved trees in young Scots pine small pole stage stands. The number of large habitat trees steadily increased in the DBH classes 430+ mm. The mean size of one patch decreased from 0.8 ha (1992) to 0.4 ha (2013). The spatial proportion of the target forest type (uneven-aged oak-dominated forest) increased from 8.5% in 1992 to 45.0% in 2013, and 35.1% of the area was fully converted during the 20 years. We expect 69.1% of the area to be converted after 30 years (2023).

Keywords: Scots Pine, Conversion, Oak Dominated Forest, Uneven-aged Silviculture, National Park

iForest 10 (1): 75-82 (2017) - doi: 10.3832/ifor1967-009
https://iforest.sisef.org/contents/?id=ifor1967-009

Research Articles: Estimating carbon dynamics in forest carbon pools under IPCC standards in South Korea using CBM-CFS3

Kim M, Lee WK, Kurz WA, Kwak DA, Morken S, Smyth CE, Ryu D — 2016-10-13

Kim M, Lee WK, Kurz WA, Kwak DA, Morken S, Smyth CE, Ryu D

ESTIMATING CARBON DYNAMICS IN FOREST CARBON POOLS UNDER IPCC STANDARDS IN SOUTH KOREA USING CBM-CFS3

Abstract: The main objective of this study was to estimate past and future dynamics of forest carbon pools in South Korea, as classified by the Intergovernmental Panel on Climate Change (IPCC) Good Practice Guidance (GPG) and to test the Carbon Budget Model of the Canadian Forest Sector 3 (CBM-CFS3). Inventory data required in CBM-CFS3 were extracted from Korea’s 3rd Forest Type Map. The site index in the inventory data was estimated through regression models developed using 5th National Forest Inventory (NFI) data with 4000 plots. Necessary yield tables to a stand age of over 100 years, stratified by species, were prepared through the estimation of volume per ha with tree species, site index and stand age. We considered thinning and cutting regulations for sustainable forest management announced by the Korean Forest Service and that the forest area was constant over from 1992 to 2092. We estimated the carbon stocks and their changes of aboveground (AGB) and belowground (BGB) biomass, litter (L), dead wood (DW), and soil organic matter (SOM). Validation was conducted based on the 5th NFI and statistical data. Our results showed that the carbon content of the total forest area increased from 509.7 Tg C to 1007.3 Tg C at a rate of 11.8 Tg C yr-1 during 1992-2034. Results also showed that AGB, BGB, DW, L and SOM changed from 54.6, 30.2, 15.9, 43.6, and 373.9 Tg C in 1992 to 455.6, 100.77, 32.89, 65.46, and 369.2 Tg C in 2034, respectively. However, the amount of forest carbon was projected to decrease due to large increases in harvest rates as most of the forest reaches the legislated cutting age during 2035-2045. Our simulation estimated that by 2045 AGB, BGB, and SOM decreased to 347.8, 78.2, and 368.9 Tg C, respectively, while DW and L increased to 46.8 and 89.1 Tg C, respectively. The carbon content of the total forested area starts to stabilize after 2045 as the annual stand growth gradually decreases. Finally in 2092, the carbon content of AGB, BGB, DW, L, and SOM was estimated as 422.3, 93.9, 31.2, 63.0, and 365.1 Tg C, respectively. Through harvesting, over the 100 year period more than 200 Tg C were transferred from South Korea’s forests to meet demands for timber, fiber and energy. Good agreement between model results, NFI data and independent studies, demonstrates the applicability of CBM-CFS3 for estimating past and future forest carbon budgets in South Korean forests and for exploring forest management activity impacts in managed forests.

Keywords: CBM-CFS3, Carbon Dynamics, Forest Management, National Forest Inventory, Forest Type Map

iForest 10 (1): 83-92 (2017) - doi: 10.3832/ifor2040-009
https://iforest.sisef.org/contents/?id=ifor2040-009

Short Communications: A quick screening to assess the phytoextraction potential of cadmium and copper in Quercus pubescens plantlets

Di Santo P, Cocozza C, Tognetti R, Palumbo G, Iorio ED, Paura B — 2016-10-13

Di Santo P, Cocozza C, Tognetti R, Palumbo G, Iorio ED, Paura B

A QUICK SCREENING TO ASSESS THE PHYTOEXTRACTION POTENTIAL OF CADMIUM AND COPPER IN QUERCUS PUBESCENS PLANTLETS

Abstract: The relevance of the environmental pollution by heavy metals warrants the necessity to develop and assess more efficient plant-based technologies. This study was conducted to evaluate a quick screening approach in order to investigate the cadmium (Cd) and copper (Cu) phytoextraction potential of Quercus pubescens in a micro-propagation system. Increasing concentrations of Cd (0, 5, 50, and 250 µM) and Cu (0, 5, 50, 250 and 500 µM) were separately applied to evaluate the effect of metals on their absorption and accumulation in downy oak plants. At high concentrations, Cd and Cu significantly reduced the dry biomass of shoots and roots and the plant tolerance index. Cd was toxic at increasing concentrations, inducing higher reduction of shoot dry mass than roots, whereas Cu increased dry mass at 5 µM. This study represents the first attempt to assess Cd and Cu uptake in Q. pubescens under in vitro conditions. The in vitro screening potential is meanly related to the following purposes: (i) proper selection of plant materials resilient to excess metals in the growth substrate; (ii) efficient removal of metals by the selected tree species; (iii) minor interference with the growth of plants accumulating metals in their tissues; (iv) rapid provision of plant materials for tree breeding programs.

Keywords: Heavy Metals, Phytoremediation, Downy Oak, Micropropagation

iForest 10 (1): 93-98 (2017) - doi: 10.3832/ifor1999-009
https://iforest.sisef.org/contents/?id=ifor1999-009

Research Articles: Forecasting the field performance of Austrian pine seedlings using morphological attributes

Ivetić V, Grossnickle S, Škorić M — 2016-10-13

Ivetić V, Grossnickle S, Škorić M

FORECASTING THE FIELD PERFORMANCE OF AUSTRIAN PINE SEEDLINGS USING MORPHOLOGICAL ATTRIBUTES

Abstract: This study examined whether the morphological attributes of Austrian pine (Pinus nigra ssp. nigra var. nigra Arnold) seedlings measured in the nursery could be used to forecast subsequent field performance over an extended time frame. Seedlings from three seed sources were produced in two types of containers and in bareroot seedbeds. These seedlings were measured for an array of morphological attributes (height, HT; root collar diameter, RCD; shoot height/diameter ratio, HD; shoot and root dry weight, SDW and RDW, respectively; shoot:root ratio, S:R; number of the first order lateral roots, FOLR; and Dickson quality index, DQI) and then planted at two sample plots with different soil depth. Seedling attributes were tested against field survival and growth in the first three years and growth in the twelfth year for their ability to forecast field performance. Correlations between morphological attributes and field performance were stronger for the plot with shallower soil, having potentially drier conditions. HT, HD, and S:R were the best attributes for forecasting seedling survival. HD was the most reliable attribute to forecast growth during the first three years after planting, defining the largest proportion of variation for growth (r2=0.36 to 0.86). Morphological attributes were better able to forecast field performance in the first three years at the shallow soil site, with FOLR the best single morphological variable. HT, DIA, and RDW were the best attributes to forecast growth during the first three years after planting on both sites. Morphological attributes were not able to forecast growth 12 years after planting.

Keywords: Seedling Quality, Seedling Performance, Reforestation, Pinus nigra

iForest 10 (1): 99-107 (2017) - doi: 10.3832/ifor1722-009
https://iforest.sisef.org/contents/?id=ifor1722-009

Research Articles: Probabilistic prediction of daily fire occurrence in the Mediterranean with readily available spatio-temporal data

Papakosta P, Straub D — 2016-10-06

Papakosta P, Straub D

PROBABILISTIC PREDICTION OF DAILY FIRE OCCURRENCE IN THE MEDITERRANEAN WITH READILY AVAILABLE SPATIO-TEMPORAL DATA

Abstract: The prediction of wildfire occurrence is an important component of fire management. We have developed probabilistic daily fire prediction models for a Mediterranean region of Europe (Cyprus) at the mesoscale, based on Poisson regression. The models use only readily available spatio-temporal data, which enables their use in an operational setting. Influencing factors included in the models are weather conditions, land cover and human presence. We found that the influence of weather conditions on fire danger in the studied area can be expressed through the FWI component of the Canadian Forest Fire Weather Index System. However, the prediction ability of FWI alone was limited. A model that additionally includes land cover types, population density and road density was found to provide significantly improved predictions. We validated the probabilistic prediction provided by the model with a test data set and illustrate it with maps for selected days.

Keywords: Fire Occurrence, Prediction, Canadian Forest Fire Weather Index, Poisson Regression

iForest 10 (1): 32-40 (2017) - doi: 10.3832/ifor1686-009
https://iforest.sisef.org/contents/?id=ifor1686-009

Research Articles: Former charcoal platforms in Mediterranean forest areas: a hostile microhabitat for the recolonization by woody species

Carrari E, Ampoorter E, Verheyen K, Coppi A, Selvi F — 2016-10-06

Carrari E, Ampoorter E, Verheyen K, Coppi A, Selvi F

FORMER CHARCOAL PLATFORMS IN MEDITERRANEAN FOREST AREAS: A HOSTILE MICROHABITAT FOR THE RECOLONIZATION BY WOODY SPECIES

Abstract: Production of wood charcoal is a traditional form of forest use that lasted for millennia in the Mediterranean countries. Following their almost complete abandonment in the last century, thousands of old charcoal platforms remain in present-day forest landscapes. These sites are characterized by peculiar ecological conditions, whose effects on the recolonization by woody plants are still unknown. We examined 61 platforms in evergreen sclerophyllous woodlands and deciduous broadleaf forests with oaks and beech, spread over a wide geographic range in Tuscany (Italy). At each site, one kiln plot (on charcoal platform) and one control plot (in the adjacent stand) were established, and soil, light conditions and herb cover were measured. We examined species richness and composition of trees and shrubs in the understorey layer (<1.3 m) and in the “established regeneration” layer (> 1.3-4 m). In the latter, structural parameters such as number of stools, dbh, mean height and number of stems were compared. The density of seedlings of dominant tree species in the understorey was also measured in a subsample of sites per forest type. In the understorey, a general positive effect of kiln platforms was found on species richness at both the habitat and plot-scale level, as well as on species composition, especially in oak forests. Increased light availability, total C content and soil pH were positively related with species richness, while N content was a negative predictor. Density of seedlings was not substantially affected. Contrastingly, woody species richness in the established regeneration layer was considerably lower in the kiln plots of all three forest types. In sclerophyllous forests, all species in this layer were taller, denser and with a higher basal area compared to control plots, while regeneration was completely lacking on platforms of the two other forest types. Soil N content had a positive influence on structural parameters, while total C content resulting from charcoal accumulation had a negative influence. We conclude that charcoal platforms are a favorable microhabitat only in the first regeneration stages of woody species, as their further growth is hindered by long-term effects that should be investigated with an experimental approach.

Keywords: Charcoal Platforms, Diversity, Forest Recolonization, Mediterranean Area, Tree Regeneration, Species Composition, Woody Species

iForest 10 (1): 136-144 (2017) - doi: 10.3832/ifor1701-009
https://iforest.sisef.org/contents/?id=ifor1701-009

Research Articles: Wind contribution to yearly silver fir (Abies alba Mill.) compression wood development in the Romanian Carpathians

Dinulica F, Marcu V, Borz SA, Vasilescu MM, Petritan IC — 2016-10-02

Dinulica F, Marcu V, Borz SA, Vasilescu MM, Petritan IC

WIND CONTRIBUTION TO YEARLY SILVER FIR (ABIES ALBA MILL.) COMPRESSION WOOD DEVELOPMENT IN THE ROMANIAN CARPATHIANS

Abstract: Since the 1950s, wind has represented one of the main disturbances to forest ecosystems in Europe, causing an increase in the frequency and amount of trees uprooted or broken by wind. Such phenomenon has also increased the incidence of compression wood in the xylem of remnant trees, thus leading to a general decrease in timber quality. In this study, we aimed to determine how wind regime affects the incidence of compression wood by reconstructing its chronology at both inter- and intra-annual scale using dendroclimatic methods. Six silver fir stands at different elevations were selected in central Romania, and compression wood time series were obtained from both increment cores from standing trees and radial discs from felled trees. Wood-structure variables were statistically analyzed as time series, while fluctuations of wind frequency and speed over the period 1921-present were reconstructed based on meteorological data. The structural response of sampled trees to wind was assessed based on the annual fluctuation in the frequency and intensity of compression wood. Results showed that the incidence of compression wood in the time series was synchronized with the intensity of the wind, rather than its duration. Wind regime in December of the preceding calendar year was significantly correlated with the frequency of compression wood, whereas its intensity was significantly correlated with wind load of previous September. The response of cambium to the wind stimulus increased with distance from the tree collar, peaking in the section at the base of the crown. At a decennial scale, only high-intensity wind stress triggered structural responses in the studied trees. Wind effects on xylogenesis in the analyzed stands increased over the last decades as a consequence of the local forest management. A better understanding of the structural response of forest trees to wind regime may explain how individual and groups of trees compete for stability and can help to improve forest management strategies in windy regions.

Keywords: Reaction Wood, Wind Regime, Dendroclimatology, Silver Fir, Carpathian Mountains

iForest 9 (6): 927-936 (2016) - doi: 10.3832/ifor1742-008
https://iforest.sisef.org/contents/?id=ifor1742-008

Research Articles: Substrates and nutrient addition rates affect morphology and physiology of Pinus leiophylla seedlings in the nursery stage

Buendía Velázquez MV, López López M&, Cetina Alcalá VM, Diakite L — 2016-10-02

Buendía Velázquez MV, López López M&, Cetina Alcalá VM, Diakite L

SUBSTRATES AND NUTRIENT ADDITION RATES AFFECT MORPHOLOGY AND PHYSIOLOGY OF PINUS LEIOPHYLLA SEEDLINGS IN THE NURSERY STAGE

Abstract: Production of forest seedlings is expensive mainly due to the use of inputs such as peat moss and fertilizers. Seedling survival in field conditions is low when seedlings with limited internal nutrient reserves are used in low fertility sites. In this work, raw sawdust and exponential fertilization were tested against peat-moss and constant fertilization, the common components of containerized seedling production systems in Mexico. The experiment was carried out under nursery conditions by using a complete randomized experimental design with a 2×2 factorial arrangement. Two substrates ’â‚¬â€š peat-moss (PM) and sawdust (SA) ’â‚¬â€š and two nutrient addition rates ’â‚¬â€š constant (CR) and exponential (ER) ’â‚¬â€š were tested. The response of seedlings was assessed based on diameter at the root collar, seedling height, dry weight (shoot, root, total and 100-needle), Dickson quality index (DQI), slenderness index (SI), and foliar nutrient concentrations and contents. Analysis of variance indicated that the substrate significantly affect all dry weights, with the greatest biomass observed for PM. Similarly, DQI and SI were affected by the substrate, with PM showing the best DQI and highest SI. Neither plant quality variables nor dry weights were affected by nutrient addition rates. Both substrate and nutrient addition rate significantly affected N, P, and K foliar concentrations. At the end of the production cycle, SA promoted higher foliar concentrations of N and P than PM, but not those of K. This suggests that K limited the growth of seedlings in sawdust, likely due to the low capacity of this substrate to adsorb K. ER produced needle concentrations of N, P, and K significantly higher than those of CR (2.65 vs. 2.26 %, 2303 vs. 2011 ppm, and 4235 vs. 3949 ppm, respectively). Our results indicate that ER is likely to give rise to more suited seedlings for outplanting in low fertility sites than CR.

Keywords: Pinus leiophylla, Peat-moss, Sawdust, Constant and Exponential Fertilization Rate

iForest 10 (1): 115-120 (2017) - doi: 10.3832/ifor1982-009
https://iforest.sisef.org/contents/?id=ifor1982-009

Research Articles: Effects of brassinosteroid application on seed germination of Norway spruce, Scots pine, Douglas fir and English oak

Kuneš I, Baláš M, Linda R, Gallo J, Nováková O — 2016-10-02

Kuneš I, Baláš M, Linda R, Gallo J, Nováková O

EFFECTS OF BRASSINOSTEROID APPLICATION ON SEED GERMINATION OF NORWAY SPRUCE, SCOTS PINE, DOUGLAS FIR AND ENGLISH OAK

Abstract: We tested the influence of a synthetically-produced brassinosteroid compound (2α,3α,17βtrihydroxy-5α-androstan-6-one) on seed germination in Norway spruce, Scots pine, Douglas fir and English oak. Before germination, 400 seeds of each species were steeped in a brassinosteroid solution and then placed for germination in a growth chamber under (i) optimal humidity and (ii) temporary drought stress (except for oak). Drought stress significantly reduced the germination capacity and germination rate in the control treatments of Norway spruce, Scots pine and Douglas fir. Nonetheless, the application of brassinosteroid significantly reduced the drought-stress effects in seeds of Norway spruce and Scots pine. The drought-stressed Douglas fir did not respond positively to the brassinosteroid application. English oak was germinated only under the optimal humidity regime and no differences in germination were detected between the control and brassinosteroid-treated acorns.

Keywords: Plant Hormones, Germination Percentage, Germination Rate, Picea abies, Pseudotsuga menziesii

iForest 10 (1): 121-127 (2017) - doi: 10.3832/ifor1578-009
https://iforest.sisef.org/contents/?id=ifor1578-009

Research Articles: Growth performance and nitrogen use efficiency of two Populus hybrid clones (P. nigra × P. maximowiczii and P. trichocarpa × P. maximowiczii) in relation to soil depth in a young plantation

Euring D, Ayegbeni S, Jansen M, Tu J, Gomes Da Silva C, Polle A — 2016-09-22

Euring D, Ayegbeni S, Jansen M, Tu J, Gomes Da Silva C, Polle A

GROWTH PERFORMANCE AND NITROGEN USE EFFICIENCY OF TWO POPULUS HYBRID CLONES (P. NIGRA × P. MAXIMOWICZII AND P. TRICHOCARPA × P. MAXIMOWICZII) IN RELATION TO SOIL DEPTH IN A YOUNG PLANTATION

Abstract: It is a challenge to produce woody crops on marginal land. The goal of this study was to examine growth responses and nitrogen use efficiency of different poplar species on shallow soil. Typical biomass poplar clones of Max1 (P. nigra × P. maximowiczii) and H275 (P. trichocarpa × P. maximowiczii) were planted on a marginal site where a gradient in soil depth was present. The growth, biomass production, and nitrogen uptake rate as well as nitrogen use efficiency of Max1 and H275 were determined for three consecutive years. Both poplar clones showed decreased growth and biomass production in the shallow soil regions. Max1 showed better adaptation to shallow soil with higher survival rate and more biomass production than H275. Max1 had lower nitrogen use efficiency on shallow soil than H275. The results suggest that higher nitrogen uptake of poplar species might be an important adaptation to maintain productivity under unfavorable soil conditions.

Keywords: Biomass, Nitrogen Use Efficiency, Poplar, Shallow Soil

iForest 9 (6): 847-854 (2016) - doi: 10.3832/ifor2016-009
https://iforest.sisef.org/contents/?id=ifor2016-009

Research Articles: Modeling air pollutant removal, carbon storage, and CO2 sequestration potential of urban forests in Scotlandville, Louisiana, USA

Ning ZH, Chambers R, Abdollahi K — 2016-09-22

Ning ZH, Chambers R, Abdollahi K

MODELING AIR POLLUTANT REMOVAL, CARBON STORAGE, AND CO2 SEQUESTRATION POTENTIAL OF URBAN FORESTS IN SCOTLANDVILLE, LOUISIANA, USA

Abstract: Understanding an urban forest’s structure, function, and value can promote management decisions that will improve environmental quality and human health. Using i-Tree Eco software and its sampling and data collection protocol, an assessment of the baseline condition, ecological function, and value of the urban forests in Scotlandville (Louisiana, USA) was conducted during 2014. A stratified (by land use type) random sample plot map of the town was generated. Data from 170 field plots located throughout Scotlandville were collected, including tree species, diameter at breast height, total tree height, height to live top, height to crown base, crown width, crown dieback, crown light exposure, percent impervious surface under the tree, and direction and distance to building. Data were then entered into i-Tree Eco v5.0 and analyzed. Modeling results indicated that there are a total of 31 species and an estimated 239.000 trees in Scotlandville with a tree canopy cover of 23.7 percent; the three most common species are Black willow (Salix nigra), Water oak (Quercus nigra), and American elm (Ulmus americana); the overall tree density is 77 trees per hectare and trees with diameters of more than 15 cm (6 inches) constitute 56.5% of the population. The model estimated that annually, the urban forests in Scotlandville remove 96 tons of air pollutants; gross sequestration is about 3.880 tons of carbon and net carbon sequestration is about 3.650 tons. Each year, trees in Scotlandville are estimated to store 88.700 tons of carbon, produce 9.720 tons of oxygen, reduce runoff by 121.200 m3, reduce energy-related costs by $324.000 USD, and provide an additional $52.595 in value by reducing the amount of carbon released by power plants (a reduction of 739 tons of carbon emissions). The structural value for Scotlandville community forest is estimated at $185 million and the annual ecological functional value is estimated at 9 million USD. These results provide baseline information for management recommendations to maximize the ecological benefits provided by trees.

Keywords: Urban Forest, Pollution Removal, Carbon Sequestration, Carbon Storage, Runoff Reduction, Energy Saving, Climate Change

iForest 9 (6): 860-867 (2016) - doi: 10.3832/ifor1845-009
https://iforest.sisef.org/contents/?id=ifor1845-009

Research Articles: Carbohydrate metabolism during new root growth in transplanted Larix olgensis seedlings: post-transplant response to nursery-applied inorganic fertilizer and organic amendment

Wei H, Guo P — 2016-09-22

Wei H, Guo P

CARBOHYDRATE METABOLISM DURING NEW ROOT GROWTH IN TRANSPLANTED LARIX OLGENSIS SEEDLINGS: POST-TRANSPLANT RESPONSE TO NURSERY-APPLIED INORGANIC FERTILIZER AND ORGANIC AMENDMENT

Abstract: Sustainable agriculture often requires the incorporation of organic matter into cultural protocols as an amendment to mitigate problems caused by chemical inputs, but the responses of transplanted seedlings to such additions have not been well quantified. In this study, bare-root Changbai larch (Larix olgensis Henry) seedlings were applied with 100 or 200 kg nitrogen (N) ha-1 of inorganic fertilizer with or without chicken manure added at a rate of 10.000 kg ha-1 during nursery cultivation, obtaining four treatment combinations designated as F100+, F200+, F100-, and F200-, respectively. Over-winter seedlings were transplanted into pots and placed in a growth chamber, where the carbohydrate metabolism, biomass accumulation, root respiration, and new root number were quantified. Both initial soluble sugar and total non-structural carbohydrate (TNC) accumulation were the lowest in the F100+ treatment. However, two months later, root soluble sugar content was the highest in this treatment, while coarse-root (diameter > 2mm) carbohydrate content was the highest in the low rate of inorganic fertilizer treatment. During the two-month post-transplant period, the net carbohydrate accumulation rate (NCAR) for starch was negative for all treatments, but the NCAR value for soluble sugars was the highest in the F100+ treatment at both the root and whole-plant scales. Relative to the F200- treatment, the NCAR value for soluble sugars, final sugar content, and biomass accumulation in coarse roots, respiration rate of fine roots (diameter ≤ 2 mm), and new root number were all greater in the F100+ treatment, while new root number was increased by organic matter additions. In conclusion, the use of chicken manure as an organic amendment had the potential to enhance transplanted larch seedling performance by improving post-transplant new root number, but this application must be considered within the context of the interaction between organic amendment treatments and inorganic fertilizer applications.

Keywords: Changbai Larch, Organic Additive, Mineral Fertilizer, New Root Egress, Starch, Soluble Sugars

iForest 10 (1): 15-22 (2017) - doi: 10.3832/ifor1988-009
https://iforest.sisef.org/contents/?id=ifor1988-009

Research Articles: Arbuscular mycorrhizal colonization in black poplar roots after defoliation by a non-native and a native insect

2016-08-29

Zampieri E, Petrucco Toffolo E, Mello A, Giorcelli A, Faccoli M, Balestrini R, Gonthier P

ARBUSCULAR MYCORRHIZAL COLONIZATION IN BLACK POPLAR ROOTS AFTER DEFOLIATION BY A NON-NATIVE AND A NATIVE INSECT

Abstract: A major goal in ecology is to understand how interactions among organisms influence ecosystem services. This work compares the effects of two Lepidoptera defoliators, one non-native (Hyphantria cunea) and one native (Lymantria dispar) to Europe, on the colonization of black poplar (the Populus nigra clone “Jean Pourtet”) roots by an arbuscular mycorrhizal (AM) symbiotic fungus (Funneliformis mosseae) in a pot experiment. The effects of defoliation have also been assessed on the expression of fungal and plant genes playing a role during symbiosis. Both control and defoliated poplars have shown a low level of mycorrhization. Additionally, neither the non-native nor the native insect seem to strongly affect the AM colonization, at least at the time of observation (eight days from the end of the defoliation). Concerning the gene expression analysis, our results suggest that defoliation does not influence neither the expression of genes coding for a fungal and a plant phosphate transporter nor that of a gene coding for a fungal ATPase, and that there were no differences between defoliation carried out by the non-native and the native insect.

Keywords: Exotic, Defoliators, Arbuscular Mycorrhizal Symbiosis, qPCR, Poplar, Gene Expression

iForest 9 (6): 868-874 (2016) - doi: 10.3832/ifor1911-009
https://iforest.sisef.org/contents/?id=ifor1911-009

Research Articles: Are the new gridded DSM/DTMs of the Piemonte Region (Italy) proper for forestry? A fast and simple approach for a posteriori metric assessment

Borgogno Mondino E, Fissore V, Lessio A, Motta R — 2016-08-29

Borgogno Mondino E, Fissore V, Lessio A, Motta R

ARE THE NEW GRIDDED DSM/DTMS OF THE PIEMONTE REGION (ITALY) PROPER FOR FORESTRY? A FAST AND SIMPLE APPROACH FOR A POSTERIORI METRIC ASSESSMENT

Abstract: Aerial LiDAR (Light Detection and Ranging) derived data are widely adopted for the study and characterization of forests. In particular, LiDAR derived-CHM (Canopy Height Model) has proved essential in identifying tree height variability and estimating many forest features such as biomass and wood volume. However, CHM quality may be affected by internal limits and anomalies caused by raw data (point cloud) processing (i.e., vertical errors), which are quite often disregarded by users, thus generating potentially erroneous results in their applications. In this work, an auto-consistent procedure for the fast evaluation of CHM accuracy has been developed based on the assessment of internal anomalies affecting CHM data obtained by differencing gridded DSM (Digital Surface Model) and DTM (Digital Terrain Model). To this purpose, a CHM was generated using the gridded DTMs and DSMs provided by the Cartographic Office of the Piemonte Region (north-western Italy). We estimated the local potential CHM error over the whole region, and demonstrated its strictly dependence on the terrain morphometry, particularly slope. The relationship between potential CHM error and slope was modeled separately for mountain, hill and flat terrain contexts, and used to produce a potential error map over the whole region. Our results showed that approximately 20% of the regional territory suffers from CHM uncertainty (in particular high elevation areas, including the treeline), though the majority of regional forest categories was affected by negligible CHM error. The potential consequences of CHM error in forest applications were evaluated, concluding that the tested LiDAR dataset provide a reliable basis for forest applications in most of the regional territory.

Keywords: ALS, LiDAR, CHM, Data Quality, Vertical Errors, Slope Effect, Forest Applications

iForest 9 (6): 901-909 (2016) - doi: 10.3832/ifor1992-009
https://iforest.sisef.org/contents/?id=ifor1992-009

Short Communications: Growth of Stone pine (Pinus pinea L.) European provenances in central Chile

2016-08-29

Loewe Muñoz V, Balzarini M, Delard Rodríguez C, Álvarez Contreras A, Navarro-Cerrillo RM

GROWTH OF STONE PINE (PINUS PINEA L.) EUROPEAN PROVENANCES IN CENTRAL CHILE

Abstract: Pinus pinea is characterized by phenotypic plasticity, tolerance to harsh soils and climates, but low differentiation in growth parameters and low genetic variability. Growth and cone production of six European stone pine provenances (two from Italy, three from Spain and one from Slovenia) were analyzed in a field trial experiment established in central Chile. The study evaluated height, diameter at breast height (DBH) and crown diameter growth of 147 nineteen-year-old trees per provenance, as well as fruiting variables (i.e., number of cones per tree and cone weight). Survival over the first 7 years was also evaluated. Provenances significantly differed in cone number per tree, cone weight, height and DBH growth, and crown diameter growth. Provenances were grouped according to growth and production variables: one group included the Italian and Slovenian provenances, the second group Andalucía and Sierra Morena (Spain), and the third included Meseta Castellana (Spain). Individual cone production was positively correlated with cone weight and other growth variables. Meseta Castellana provenance showed the highest growth and productivity. Our results provide useful information for the selection of P. pinea provenances to be used in new plantations in central Chile.

Keywords: Cone Productivity, Growth, Provenances, Stone Pine Plantations

iForest 10 (1): 64-69 (2017) - doi: 10.3832/ifor1984-009
https://iforest.sisef.org/contents/?id=ifor1984-009

Research Articles: Diurnal dynamics of water transport, storage and hydraulic conductivity in pine trees under seasonal drought

Klein T, Cohen S, Paudel I, Preisler Y, Rotenberg E, Yakir D — 2016-08-21

Klein T, Cohen S, Paudel I, Preisler Y, Rotenberg E, Yakir D

DIURNAL DYNAMICS OF WATER TRANSPORT, STORAGE AND HYDRAULIC CONDUCTIVITY IN PINE TREES UNDER SEASONAL DROUGHT

Abstract: The temporal dynamics of water transport and storage in plants have major implications for plant functioning and survival. In trees, stress on the conductive tissue can be moderated by water storage. Yet, trees can survive high percent loss of conductivity (PLC, up to 80%), suggesting efficient recovery. We assess the role of tree water storage and PLC recovery based on simultaneous measurements of leaf transpiration, branch hydraulic conductivity, and stem sap-flow from different seasons in three study years in mature Pinus halepensis (Miller) trees in a semi-arid forest. During the wet season the rates of transpiration (T) and sap flow (SF) peaked at high morning and through the mid-day. During the dry season T peaked at ~9:00 and then decreased, whereas SF lagged T and fully compensated for it only in the evening, resulting in a mid-day water deficit of ~5 kg tree-1, and with up to 33% of daily T derived from storage. PLC of 30-40% developed during mid-day and subsequently recovered to near zero within 2-3 hr in the dry season (May, June, and September), but not in the wet season (January). The observed temporal decoupling between leaf water loss and soil water recharge is consistent with optimization of the trees’ water and gas exchange economy, while apparently facilitating their survival in the semi-arid conditions.

Keywords: Cavitation Reversal, Sap Flow, Semi-arid, Water Deficit, Xylem Embolism.

iForest 9 (5): 710-719 (2016) - doi: 10.3832/ifor2046-009
https://iforest.sisef.org/contents/?id=ifor2046-009

Research Articles: Relationships between overstory and understory structure and diversity in semi-natural mixed floodplain forests at Bosco Fontana (Italy)

Chianucci F, Minari E, Fardusi MJ, Merlini P, Cutini A, Corona P, Mason F — 2016-08-21

Chianucci F, Minari E, Fardusi MJ, Merlini P, Cutini A, Corona P, Mason F

RELATIONSHIPS BETWEEN OVERSTORY AND UNDERSTORY STRUCTURE AND DIVERSITY IN SEMI-NATURAL MIXED FLOODPLAIN FORESTS AT BOSCO FONTANA (ITALY)

Abstract: The “Bosco Fontana” natural reserve includes the last remaining mixed floodplain forest in northern Italy and one of the most endangered ecosystems in Europe. Its effective management is hindered by the complexity of interactions of mixed-tree species and the influence of environmental factors on understory plant diversity. In this study we analyzed the patterns of natural evolution in semi-natural floodplain forest stands at Bosco Fontana with the aim of better understanding its current natural processes and dynamics. Stand structure, taxonomic and functional diversity, species composition, and leaf area index (LAI) of overstory and understory layers were surveyed in permanent plots over two inventory years (1995, 2005). The influence of environmental factors on understory plant diversity was assessed using Ellenberg’s indices for light, soil moisture, soil nutrient and soil reaction. Results indicated that overstory species composition varies according to the soil moisture, with hornbeam prevailing in xeric sites and deciduous oak species in mesic sites. Xeric sites showed high functional dispersion in both drought and shade tolerant traits, while it was significantly lower in both overstory and understory in the moist site. Functional dispersion of drought tolerance in the overstory and understory layers was positively correlated, while species richness was negatively correlated between the two layers. Diversity in the understory was mainly correlated with soil conditions. Understory LAI was positively correlated with overstory LAI in xeric and mesic plots, while no correlations were found in the moist plot. Overall, our results suggest that site conditions (soil conditions and water availability) are the major drivers of understory and overstory dynamics in the study forest. Hence, local site conditions and the understory should be carefully considered in the management of mixed floodplain forests.

Keywords: Deciduous Forests, Functional Diversity, Diversity Measure, Hemispherical Photography, Leaf Area Index

iForest 9 (6): 919-926 (2016) - doi: 10.3832/ifor1789-009
https://iforest.sisef.org/contents/?id=ifor1789-009

Research Articles: Methods for biomass stock estimation in Mediterranean maquis systems

Sirca C, Caddeo A, Spano D, Bacciu V, Marras S — 2016-08-21

Sirca C, Caddeo A, Spano D, Bacciu V, Marras S

METHODS FOR BIOMASS STOCK ESTIMATION IN MEDITERRANEAN MAQUIS SYSTEMS

Abstract: As a result of Kyoto Protocol agreements, the scientific community increased its efforts to enhance the availability of biomass and organic carbon stock data in forest ecosystems. Nevertheless, a considerable data shortage has been recognized in estimating the stock of above-ground biomass (AGB) in Mediterranean maquis systems. This work aims at contributing in addressing such shortage by testing quick and non-disruptive methods to estimate the AGB stock in maquis species. Two methodologies were tested in three widespread sclerophyllous evergreen species (Pistacia lentiscus, Euphorbia dendroides, and Cystus monspeliensis). Both methodologies were based on the estimation of the apparent volume (AV): the first one assumed the shrub shape (or canopy) to be similar to a regular tridimensional solid, while the second method was based on plant digital images analysis. Results showed some differences in AV values estimated through the two methodologies, although a high correlation was found between them (R2 = 0.92-0.98) and with the AGB weight obtained from plant samples (R2 = 0.89-0.96). As a consequence, the shrubs apparent density values (i.e., weight/AV) vary depending on the method used for AV estimation. This should be taken into account when AV is used for AGB estimation. Besides, measurements of above-ground biomass were carried out to characterize the studied area. Results showed high variability in AGB values, ranging from 7.04 to 48.05 Mg ha-1 of dry matter.

Keywords: Shrubland, Allometric Equations, Above Ground Biomass, Apparent Volume

iForest 10 (1): 108-114 (2017) - doi: 10.3832/ifor1769-009
https://iforest.sisef.org/contents/?id=ifor1769-009

Research Articles: Integrating forest-based industry and forest resource modeling

Jonsson R, Rinaldi F, Räty M, Sallnäs O — 2016-08-12

Jonsson R, Rinaldi F, Räty M, Sallnäs O

INTEGRATING FOREST-BASED INDUSTRY AND FOREST RESOURCE MODELING

Abstract: This paper introduces a modeling approach for the assessment of policy options within the forest-based bioeconomy. The feedback between the forestry dynamics model and the economic model of the global forest-based sector of the proposed framework is essential, not only for response analysis as to the development of forest resources and for a correct assessment of future harvesting potentials, but also for the assessment of the impact of different management regimes on wood-based product markets. Test runs of the modeling framework on a Swedish case highlight the necessity of considering timber assortments for a comprehensive integration of forest resources and wood-based commodity market dynamics. Hence, the composition of harvest demand in terms of timber assortment affects the allocation of harvesting activities and, consequently, the development of forest resources (and thus future harvest potentials), as well as the production, trade and consumption of wood-based products.

Keywords: Policy, Bioeconomy, Wood-based Products, Market, Forest Resources

iForest 9 (5): 743-750 (2016) - doi: 10.3832/ifor1961-009
https://iforest.sisef.org/contents/?id=ifor1961-009

Research Articles: Tolerance to heavy metal stress in seedlings of three pine species from contrasting environmental conditions in Chile

Arencibia AD, Rodríguez C, Roco L, Vergara C, González-Soto N, García-González R — 2016-08-12

Arencibia AD, Rodríguez C, Roco L, Vergara C, González-Soto N, García-González R

TOLERANCE TO HEAVY METAL STRESS IN SEEDLINGS OF THREE PINE SPECIES FROM CONTRASTING ENVIRONMENTAL CONDITIONS IN CHILE

Abstract: Tolerance to metal stress was studied in seedlings of three pine species (Pinus radiata, P. pinaster and P. canariensis) under controlled ex vitro conditions. Mature female cones were randomly collected at two sites in Chile (Llico and Huilquilemu) characterized by contrasting environmental conditions. One-year-old pine seedlings were immersed in trays with solutions of CuSO4 (300 mM) or AlCl3 (100 mM), and their survival, growth rate and decay symptoms were recorded for 60 days. Results showed large differences among provenances in seedling tolerance to CuSO4 and AlCl3 in terms of survival and growth. Multivariate analysis revealed a significant association (p <0.0001) between the first canonical function and the following variables: provenance, species, metal stress and growing rate, as well as between the second canonical function and provenance, species, metal stress and symptomatology, indicating a high degree of genotype-environment interaction. Moreover, the activity of POX, SOD and CAT enzymes was determined 60 days after the beginning of the experiment in the Llico provenance seedlings. P. pinaster showed the highest activity level for all the enzymes considered, while P. canariensis and P. radiata had intermediate and lowest values, respectively. Differential gene expression among pine seedlings under metal stress with CuSO4 for two genes (Cu-Zn-superoxide dismutase and RuBisCo) confirmed P. pinaster as the most tolerant species to CuSO4 treatment. Our results are consistent with the hypothesis that abiotic stress in the maternal environment can induce a “transgenerational plasticity” which could affect progeny performances. The influence of different genetic backgrounds on the tolerance to heavy metals in pine seedlings is also discussed.

Keywords: Pinus spp., Heavy Metals, Abiotic Stresses, Genotype-Environment Interaction

iForest 9 (6): 937-945 (2016) - doi: 10.3832/ifor1908-009
https://iforest.sisef.org/contents/?id=ifor1908-009

Review Papers: Opportunities for coppice management at the landscape level: the Italian experience

2016-08-04

Mairota P, Manetti MC, Amorini E, Pelleri F, Terradura M, Frattegiani M, Savini P, Grohmann F, Mori P, Terzuolo PG, Piussi P

OPPORTUNITIES FOR COPPICE MANAGEMENT AT THE LANDSCAPE LEVEL: THE ITALIAN EXPERIENCE

Abstract: Coppice silviculture has a long tradition in Italy. Societal demands have led to the development of forest management techniques for integrating wood production with other kinds of forest uses and regulations have been issued to limit forest degradation. In Italy, 35% of the national forest cover is currently managed under coppice silvicultural systems that provide 66% of the annual wood production. Fuel-wood demand is increasing and a large amount of fuel-wood is currently imported in Italy. Modern coppice practices differ from those adopted in the past and may have a reduced impact on ecosystem characteristics and processes. Nevertheless, coppice silviculture has a bad reputation mostly on grounds that are beyond economic, technical and ecological rationales. Neither cessation of use nor a generalized conversion from coppice to high forest are likely to respond simultaneously to the many demands deriving from complex and articulated political and economic perspectives operating at global, European, national, regional and forest stand-level scales. Different approaches of modern silviculture to coppice successfully tested in Italy for more than a decade are illustrated. We propose to combine different options at the stand and sub-stand level, including either development without human interference or conversion to high forest, and to apply these approaches within the framework of novel forest management plans and regionally consistent administrative procedures. This bottom-up approach represents a potential solution to the socio-economic and environmental challenges affecting coppicing as a silvicultural system.

Keywords: Biodiversity, Coppice Silviculture, Environmental Change, Landscape, Socio-economic Dynamics, Sustainable Forest Management

iForest 9 (5): 775-782 (2016) - doi: 10.3832/ifor1865-009
https://iforest.sisef.org/contents/?id=ifor1865-009

Research Articles: Tree-oriented silviculture: a new approach for coppice stands

Manetti MC, Becagli C, Sansone D, Pelleri F — 2016-08-04

Manetti MC, Becagli C, Sansone D, Pelleri F

TREE-ORIENTED SILVICULTURE: A NEW APPROACH FOR COPPICE STANDS

Abstract: Tree-oriented silviculture is an innovative approach of forest management aimed at enhancing a limited number of early-selected crop trees whose growth is favored over the full rotation period by applying frequent thinning in their neighborhood. This approach was originally applied to high forests, but can also be applied to coppices to maintain or improve biodiversity by selecting valuable timber trees and/or minority species as target trees. The main limitation of this silvicultural option is the need of specialized and qualified operators in all the phases, from selection of crop trees to logging operations. In this study, experimental trials were established by the Forest Research Centre of Arezzo (Italy) to verify the suitability of this approach to different structural and enviromental conditions. In coppices characterized by fast growing species such as chestnut, tree-oriented silviculture has been applied to a limited number of crop trees (50-100 ha) to obtain more valuable and larger-sized assortments in a shorter rotation period, reducing at the same time the silvicultural costs. In mixed coppices, where the ordinary management (coppicing) was applied, the abandonment or the conversion into high forest gave rise to a progressive loss in terms of species composition. Contrastingly, thinning focused around a few (5-20) trees of sporadic species allowed to maintain a high level of biodiversity, and led to favorable conditions for growth and regeneration of these species.

Keywords: Tree-oriented Silviculture, Valuable Timber, Biodiversity, Thinning Practice

iForest 9 (5): 791-800 (2016) - doi: 10.3832/ifor1827-009
https://iforest.sisef.org/contents/?id=ifor1827-009

Research Articles: The losses of condensed tannins in six foliar litters vary with gap position and season in an alpine forest

Li H, Wu F, Yang W, Xu L, Ni X, He J, Tan B, Hu Y, Justin MF — 2016-08-04

Li H, Wu F, Yang W, Xu L, Ni X, He J, Tan B, Hu Y, Justin MF

THE LOSSES OF CONDENSED TANNINS IN SIX FOLIAR LITTERS VARY WITH GAP POSITION AND SEASON IN AN ALPINE FOREST

Abstract: Condensed tannins (CTs) have been considered to be intrinsic variables that determine litter decomposition. Forest gaps and the surrounding crown canopies may locally influence the microenvironmental factors, thus affecting the losses of CTs from litter. However, little information is available about the dynamics of CTs loss in forest gaps. In this study, litterbags containing foliar litter of Minjiang fir (Abies faxoniana), red birch (Betula albosinensis), Masters larch (Larix mastersiana), cypress (Sabina saltuaria), Kangding willow (Salix paraplesia), and Lapland azalea (Rhododendron lapponicum), were placed on the forest floor at differet positions from the gap center to the closed canopy in the alpine Minjiang fir forest located in the upper reaches of the Yangtze River and the eastern Tibetan Plateau (China). The samples were retrieved during the periods of snow formation, snow cover, snow melt and in the growing season, and the CTs content was measured at each time point. During the first year, all six types of foliar litter experienced high losses of CTs with values ranging from 70.18% to 96.67%. Forest gaps accelerated litter CTs losses in the winter but inhibited CTs losses in the growing season, which demonstrated significant seasonal differences. Additionally, the litter of conifers exhibited greater CTs losses in the winter, especially during the snow formation period, whereas the litter of broadleaved trees showed greater CTs losses during the growing season. These results indicate that the predicted reductions in snow depth resulting from future winter warming and the loss of forest gaps due to forest regeneration will inhibit the decomposition of CTs in the litter of alpine forest ecosystems, which will slow soil carbon sequestration from foliar litter in cold biomes.

Keywords: Forest Gap, Condensed Tannins, Foliar Litter, Seasonal Snowpack, Alpine Forest

iForest 9 (6): 910-918 (2016) - doi: 10.3832/ifor1738-009
https://iforest.sisef.org/contents/?id=ifor1738-009

Research Articles: Trade-offs and spatial variation of functional traits of tree species in a subtropical forest in southern Brazil

2016-07-07

Missio FDF, Higuchi P, Silva ACD, Longhi SJ, Salami B, Dalla Rosa A, Buzzi-Junior F, Ferreira TDS, Koche Marcon A, Bento MA

TRADE-OFFS AND SPATIAL VARIATION OF FUNCTIONAL TRAITS OF TREE SPECIES IN A SUBTROPICAL FOREST IN SOUTHERN BRAZIL

Abstract: Plant functional traits have been recognized as important factors related to the ecological strategies of species in forest ecosystems. We examined the relationships between functional traits and both tree species performance and environmental conditions in a subtropical forest in Brazil. Over four years (2008-2012), we investigated how demographic rates were related to functional traits (wood density, leaf area and tree height) of 20 species sampled within 50 plots of 10 × 20 m, which had previously evaluated as to environmental conditions. Non-metric multidimensional scaling was used to order the species by their functional traits. The demographic rates were fit a posteriori to the ordination, with significant rates (p < 0.05) plotted as vectors. The relationships between environmental conditions and the community-weighted means (CWMs) of trait values were verified using redundancy analysis. CWM wood density was positively correlated with soil pH. CWM leaf area and CWM maximum tree height were both negatively correlated with altitude and positively correlated with soil magnesium (Mg) content. The taller species with lower wood density, which occupied the forest canopy, had a greater diameter increment and lower recruitment than did the shortest species with higher wood density. The shorter species with higher wood density, which occupied the understory, had greater recruitment and a greater increase in abundance than did the taller/lower-wood-density species. Our study (i) revealed changes in the forest related to the light environment, with an increase in the relative participation of shade-tolerant species with higher wood densities, and (ii) detected small-scale spatial variation in community traits as a response to variations in soil chemical properties and topography.

Keywords: Araucaria Forest, Atlantic Forest, Environmental Heterogeneity, Multivariate Analysis

iForest 9 (6): 855-859 (2016) - doi: 10.3832/ifor1960-009
https://iforest.sisef.org/contents/?id=ifor1960-009

Research Articles: Evergreen species response to Mediterranean climate stress factors

Gratani L, Catoni R, Varone L — 2016-07-07

Gratani L, Catoni R, Varone L

EVERGREEN SPECIES RESPONSE TO MEDITERRANEAN CLIMATE STRESS FACTORS

Abstract: Recent climatic projections predict a decline in rainfall mainly during the summer period and an increase in air temperature for the Mediterranean basin, resulting in extended periods of soil water deficit. Mediterranean evergreen species attain drought resistance through different traits or combination of traits. The main objective of this research is to analyze the response of the evergreen species co-occurring in the Mediterranean maquis to variations in water availability and air temperature during the year. The results show that leaf structural traits significantly affect physiological traits as confirmed by the Partial Least Squares Regression analysis (PLS). In particular, the considered species have a similar leaf respiration (RL) trend during the year with the lowest rates in winter (mean 0.95 ± 0.44 µmol m-2 s-1) and the highest in drought (mean 3.05 ± 0.96 µmol m-2 s-1). Nevertheless, a different RL effect on gross photosynthesis (PG) during drought was observed. C. incanus, E. multiflora, R. officinalis and S. aspera have the highest RL/PG ratio (mean 0.54 ± 0.08), while Q. ilex, P. latifolia, P. lentiscus, A. unedo and E. arborea have the lowest (mean 0.22 ± 0.07). RL/PG ratio variations depend on the sensitivity of both the two parameters to drought. Considering the increase of the length and intensity of drought in the Mediterranean basin, and that the photosynthesis of Mediterranean evergreen species is frequently limited by sub-optimal conditions (i.e., water deficit, high light intensity and high air temperature), it is important to improve knowledge on RL, since it has a critical function in modulating carbon balance of Mediterranean species.

Keywords: Global Climate Change, Mediterranean Evergreen Species, Net Photosynthesis, Gross Photosynthesis, Leaf Respiration

iForest 9 (6): 946-953 (2016) - doi: 10.3832/ifor1848-009
https://iforest.sisef.org/contents/?id=ifor1848-009

Research Articles: Age trends in genetic parameters for growth and quality traits in Abies alba

Mihai G, Mirancea I — 2016-07-07

Mihai G, Mirancea I

AGE TRENDS IN GENETIC PARAMETERS FOR GROWTH AND QUALITY TRAITS IN ABIES ALBA

Abstract: Genetic parameters for growth, stem straightness, survival, wood density and percentage of late wood were estimated in a progeny test of European silver fir (Abies alba Mill.) established in Romania in 1980. The experiment was conducted on 95 families collected from 10 natural stands and five provenance regions, and trait measurements were taken 6-34 years after planting. The family effect was highly significant for 14 traits and significant for one trait. The additive genetic variance increased with age for all the studied traits, and family heritability was higher than individual heritability. Stem diameter, volume per tree, wood density and late wood were the traits with the highest heritability. The trend of individual and half-sib family heritability estimates decreased between 6 and 15 years of age for height and between 6 and 10 years for diameter, while both height and diameter heritabilities were stable at older ages. High age-age genetic correlations were observed, though genetic correlations between growth and wood density were weak. Selection at age 6-10 could increase genetic gain in volume in mature silver fir trees. Selection based on family breeding values combined with within-family selection is recommended to maximize genetic gain in breeding activities in silver fir.

Keywords: Age-age Correlations, Genetic Gain, Heritability, Optimum Age, Progeny Trial, Silver Fir

iForest 9 (6): 954-959 (2016) - doi: 10.3832/ifor1766-009
https://iforest.sisef.org/contents/?id=ifor1766-009

Research Articles: Emerging pests and diseases threaten Eucalyptus camaldulensis plantations in Sardinia, Italy

2016-06-29

Deidda A, Buffa F, Linaldeddu BT, Pinna C, Scanu B, Deiana V, Satta A, Franceschini A, Floris I

EMERGING PESTS AND DISEASES THREATEN EUCALYPTUS CAMALDULENSIS PLANTATIONS IN SARDINIA, ITALY

Abstract: The rapid growth and environmental adaptability of Eucalyptus species has favored their global cultivation for pulpwood production. On the island of Sardinia, Italy, eucalypt plantations were established in the 20th century primarily in areas reclaimed from marshland, but the trees are now grown all over the island as ornamentals or windbreaks, and for timber, pulp and honey production. In recent years, an unusual decline and mortality of unknown etiology has been observed in Eucalyptus camaldulensis (river red gum) plantations throughout the island. Given the ecological and economic importance of eucalypt ecosystems in Sardinia, a survey was carried out in 2013 to determine which insect pests and fungal pathogens are directly involved in these phenomena. Field surveys throughout the island revealed severe infestations with the red gum lerp psyllid (Glycaspis brimblecombei) at all 12 surveyed sites, with the greatest numbers of pre-imaginal stages and adults occurring between May and July. The adult population reached its peak in July, followed 2 months later by the peak population of its specific parasitoid, Psyllaephagus bliteus. Symptoms of leaf chlorosis, crown thinning, shoot and branch dieback, sunken cankers, epicormic shoots and exudations of kino gum were also observed at the 12 field sites. Symptomatic woody samples yielded fungal isolates representing three distinct families: Botryosphaeriaceae, Diaporthaceae and Valsaceae. Morphological and DNA sequence data revealed seven distinct fungal species, namely Diaporthe foeniculina, Neofusicoccum australe, N. luteum, N. mediterraneum, N. parvum, N. vitifusiforme and Valsa fabianae. Two putative new species of Cytospora were also identified. Neofusicoccum australe was the only species recovered from all 12 sites, with isolation frequencies of 51-95%. Pathogenicity trials revealed that all Neofusicoccum species except N. vitifusiforme are directly involved in the etiology of the observed decline in the E. camaldulensis population on Sardinia.

Keywords: Timber Industries, Exotic Species, Biosecurity, Invasive Pathogens and Insects

iForest 9 (6): 883-891 (2016) - doi: 10.3832/ifor1805-009
https://iforest.sisef.org/contents/?id=ifor1805-009

Research Articles: Nitrogen deposition and its impact on forest ecosystems in the Czech Republic - change in soil chemistry and ground vegetation

Novotný R, Buriánek V, Šrámek V, Hunová I, Skorepová I, Zapletal M, Lomský B — 2016-06-29

Novotný R, Buriánek V, Šrámek V, Hunová I, Skorepová I, Zapletal M, Lomský B

NITROGEN DEPOSITION AND ITS IMPACT ON FOREST ECOSYSTEMS IN THE CZECH REPUBLIC - CHANGE IN SOIL CHEMISTRY AND GROUND VEGETATION

Abstract: A repeated soil survey (1995 and 2006) on 66 ICP Forests pair plots in the Czech Republic revealed a significant relationship between modeled nitrogen deposition and nitrogen concentration in the soil. Nitrogen deposition was modeled for the years 1995, 2004 and 2006. We found a more significant relationship between deposition data in 2004 and soil data in 2006 than between deposition and soil data from the same year 2006. Concentration of total nitrogen in forest soil increased from 1995 to 2006. Forest soil showed effects of increased nitrogen input from the humus layer to around 20 cm depth of mineral soil. The occurrence and cover of nitrophilous species in the herb layer increased from 1995 to 2006 in 25% of the analyzed plots, which corresponds to the nitrogen increase in forest soil. The results suggest that nitrogen deposition still represents a threat for Czech forest ecosystems.

Keywords: Nitrogen Deposition, Soil Chemistry, Ground Vegetation, Ecosystem Changes, Norway Spruce

iForest 10 (1): 48-54 (2017) - doi: 10.3832/ifor1847-009
https://iforest.sisef.org/contents/?id=ifor1847-009

Research Articles: Physical and mechanical properties of particleboards manufactured using charcoal as additives

Kowaluk G, Zajac M, Czubak E, Auriga R — 2016-06-29

Kowaluk G, Zajac M, Czubak E, Auriga R

PHYSICAL AND MECHANICAL PROPERTIES OF PARTICLEBOARDS MANUFACTURED USING CHARCOAL AS ADDITIVES

Abstract: The objective of this work was to evaluate selected physical and mechanical properties of experimental particleboards manufactured from pine and spruce with charcoal particles in their core layer. For all the manufactured boards the average density was 750 kg m-3, while the mass share of charcoal in the core layer was changed (0%, 10% and 50%). The manufactured panels were tested with respect to their mechanical and physical properties, including formaldehyde emission. The results indicated that the share of charcoal significantly influenced mechanical properties, swelling, and water relations of the boards. In addition, a test on formaldehyde emission from panels were carried out, which revealed that the charcoal share has a considerable impact on the amount of formaldehyde released by the manufactured boards. The 50% content of charcoal caused about 80% reduction of formaldehyde emission.

Keywords: Charcoal, Particleboard, Filler, Bending, Formaldehyde, Emission

iForest 10 (1): 70-74 (2017) - doi: 10.3832/ifor1963-009
https://iforest.sisef.org/contents/?id=ifor1963-009

Research Articles: The response of intra-annual stem circumference increase of young European beech provenances to 2012-2014 weather variability

Ježík M, Blaženec M, Kučera J, Strelcová K, Ditmarová L — 2016-06-23

Ježík M, Blaženec M, Kučera J, Strelcová K, Ditmarová L

THE RESPONSE OF INTRA-ANNUAL STEM CIRCUMFERENCE INCREASE OF YOUNG EUROPEAN BEECH PROVENANCES TO 2012-2014 WEATHER VARIABILITY

Abstract: The increasing frequency and severity of extreme weather events, especially droughts, arising from on-going climate changes negatively affect productivity and stability of forest ecosystems. Understanding species responses and suitable ecotypes that are able of adapting to new environmental conditions is increasingly important. The objective of this study was to quantify the relationships between the inter-annual stem circumference increase (SCI) of five European beech (Fagus sylvatica L.) provenances and weather variability during 2012-2014 in a provenance trial located in central Slovakia. SCIs were extracted on daily and weekly scale from hourly data of circumference changes. To detect the main environmental factors influencing SCI seasonal dynamics, intra-seasonal moving correlation functions were calculated. All five provenances responded synchronously to weather conditions, with high correlations among them during the growing season on both daily and weekly scale. The photoperiod exhibited a synchronizing effect on the seasonal peak of SCI as a sign of tree adaptation to long-term seasonal variations in climate. Temperature was the most significant factor influencing SCI dynamics at the beginning of the season. During the summer months, a precipitation deficit, heat waves and the consequently decreased soil water potential significantly affected the SCI of young beech trees, despite the fact that the provenance plot was situated in an area of optimum beech growth. Not only the severity and duration were important but also the timing of drought within a season. Within all seasons, the lowest SCI values were recorded for the provenance from the lowest altitude and the most oceanic climate (northern Germany). A comparison of daily and weekly SCI with first derivatives of growth functions indicated that SCIs were closely related to theoretical incremental processes, especially on a weekly scale. In young beech trees, SCI seemed to represent an appropriate proxy for studying intra-seasonal incremental processes. A newly designed SASB (self adjusting sharp beginning) function fit these processes better than the Gompertz function.

Keywords: Stem Circumference Increase, Provenances, Fagus sylvatica, Weather Variables, Soil Water Potential

iForest 9 (6): 960-969 (2016) - doi: 10.3832/ifor1829-009
https://iforest.sisef.org/contents/?id=ifor1829-009

Technical Reports: Integration between TLS and UAV photogrammetry techniques for forestry applications

Aicardi I, Dabove P, Lingua AM, Piras M — 2016-06-23

Aicardi I, Dabove P, Lingua AM, Piras M

INTEGRATION BETWEEN TLS AND UAV PHOTOGRAMMETRY TECHNIQUES FOR FORESTRY APPLICATIONS

Abstract: Forests are significant resources from an ecological, economic and social point of view. Their protection and management could greatly benefit from a complete knowledge of the shape and distribution of trees in forest stands. To this purpose, aerial surveys, especially through Airborne Laser Scanning (ALS), were carried out in the last years to acquire point clouds to be used in 3D models aimed at achieving an accurate description of tree crowns and terrain. However, airborne data acquisition is expensive and may provide poor results in case of dense foliage. Further, point cloud resolution is not very high, as models with a grid of 2-3 m are usually obtained. In order to implement more accurate 3D forest models, a feasible solution is the integration of point clouds obtained by aerial acquisition (ALS or photogrammetry) for the treetops and the terrain description, with information from terrestrial surveys. In this paper, we investigated the possible integration of point clouds obtained by Terrestrial Laser Scanner (TLS) with those collected by photogrammetric 3D models based on images captured by Unmanned Aerial Vehicle (UAV) in a test site located in northern Italy, with the aim of creating an accurate dataset of the forest site with high resolution and precision. The limits of ALS and TLS were bridged by aerial photogrammetry at low altitude (and vice versa). A 3D model of the study area was obtained with a resolution of 5 cm and a precision of 3 cm. Such model may be used in a wide range of applications in forestry studies, e.g., the reconstruction of 3D shapes of trees or the analysis of tree growth throught time. The implications of the use of such integrate approach as a support tool for decision-making in forest management are discussed.

Keywords: Data Integration, Forestry, Laser Scanner, Photogrammetry, Unmanned Aerial Vehicle, GNSS

iForest 10 (1): 41-47 (2017) - doi: 10.3832/ifor1780-009
https://iforest.sisef.org/contents/?id=ifor1780-009

Research Articles: Physiological performance and growth of Viburnum tinus L. on phytoremediated sediments for plant nursing purpose

2016-06-23

Ugolini F, Calzolari C, Lanini GM, Massetti L, Sabatini F, Ungaro F, Damiano S, Izquierdo CG, Macci C, Masciandaro G

PHYSIOLOGICAL PERFORMANCE AND GROWTH OF VIBURNUM TINUS L. ON PHYTOREMEDIATED SEDIMENTS FOR PLANT NURSING PURPOSE

Abstract: Sediments are fundamental resources for productive activities like plant nursing, which are also likely to be responsible of their loss. In contrast, other activities like the dredging of canals and waterways involve the extraction and continuous accumulation of sediments. Most dredged sediments are polluted, and need to be stocked and transported to landfills, with extremely high costs for transport and management. To address these problems, a low-cost remediation methodology was previously developed to decontaminate sediments which were tested for use in plant nursery field plantations located in Pistoia (Italy). The phytoremediated sediments were mixed in percentages of 33% and 50% with alluvial soil, which itself was used as control. We studied the characteristics of these mixtures, and the physiological response and growth of Viburnum tinus L. grown on each substrate, as well as its corresponding root ball. Substrates with sediments showed quick water infiltration and no waterlogging, in sharp contrast to what was observed in autumn in the control. Despite a rainy summer, V. tinus demonstrated a good acclimation to the different substrates, showing the lowest leaf water potentials in mixed substrates and no signs of stress. No differences in leaf carbon assimilation or transpiration were observed among substrates, while in late August plants grown on substrates with sediments showed a higher performance index for energy conservation from photons absorbed by PSII to the reduction of intersystem electron acceptors. In the 50% mixture, there was also an enhancement of electron transport from PSII to PSI. Moreover, no differences in growth and biomass were found. Plants in all substrates showed some thin-root mortality, likely due to the persistent rainfall, though a higher number of plants with dead roots was observed in control. Thanks to the dense and fibrous root apparatus of V. tinus, the mixture with 33% sediments produced satisfactory results even for the root ball, resulting in less deformation and a lower breakage percentage.

Keywords: Biomass, Field Plantations, Leaf Gas Exchanges, Plant Nursing, PSII Efficiency, Root Balls, Sediments

iForest 10 (1): 55-63 (2017) - doi: 10.3832/ifor1840-009
https://iforest.sisef.org/contents/?id=ifor1840-009

Technical Reports: Biomass equations for European beech growing on dry sites

Chakraborty T, Saha S, Reif A — 2016-06-17

Chakraborty T, Saha S, Reif A

BIOMASS EQUATIONS FOR EUROPEAN BEECH GROWING ON DRY SITES

Abstract: Biomass equations for European beech (Fagus sylvatica L.) trees growing on dry sites have not been published, although such equations are needed for a proper estimation of the biomass of beech trees growing naturally at their drought limit in dry forests. We aimed to: (1) develop new allometric above-ground biomass equations for European beech trees growing on dry sites; (2) compare these equations with existing biomass equations. We harvested 86 plants, ranging from saplings to trees, from forest stands on south-facing slopes at 5 locations in Germany and Switzerland. Whole plant weights were measured in the field after felling, and samples from stem, branches and leaves of every harvested plant were brought to the laboratory. We developed diameter- and height-based regression equations for the total above-ground biomass, stem with bark biomass, and biomass of the branches with leaves and further compared them with the existing equations from the literature. Our results showed that the 5 current diameter-based equations available in the literature significantly overestimate the total above-ground biomass, the stem with bark biomass and the biomass of branches and leaves. With increasing tree size, the proportion of the biomass of branches and leaves to the total tree biomass decreased significantly. We also found that the inclusion of height in biomass models did not influence the prediction of total above-ground biomass, but significantly improved the prediction of stem biomass. We recommend that researchers and foresters use the equations developed in this study to quantify the biomass of beech trees growing under similar site conditions.

Keywords: Above-ground Biomass, Stem Biomass, Abandoned Oak Coppiced Forest, Stunted Growth, Plant Size Allometry

iForest 9 (5): 751-757 (2016) - doi: 10.3832/ifor1881-009
https://iforest.sisef.org/contents/?id=ifor1881-009

Research Articles: Retranslocation of foliar nutrients of deciduous tree seedlings in different soil condition under free-air O3 enrichment

Shi C, Eguchi N, Meng F, Watanabe T, Satoh F, Koike T — 2016-06-17

Shi C, Eguchi N, Meng F, Watanabe T, Satoh F, Koike T

RETRANSLOCATION OF FOLIAR NUTRIENTS OF DECIDUOUS TREE SEEDLINGS IN DIFFERENT SOIL CONDITION UNDER FREE-AIR O3 ENRICHMENT

Abstract: Retranslocation is the amount of an element that is depleted from old plant components and is provided for new growth. Leaf senescence is usually accelerated at elevated O3 (eO3), and leaf shedding is influenced by soil nutrient availability (and acidification). In this study, we focused on the net retranslocation and allocation dynamics of foliar nutrients (N, P, Mg, K, Ca, Mn, Fe and Al) to investigate the effect of eO3 on birch (Betula platyphylla var. japonica), oak (Quercus mongolica var. crispula), and beech (Fagus crenata) seedlings grown in different soil conditions. Seedlings of the 3 species were planted in a free-air O3 enrichment system under 3 soil types (brown forest soil, serpentine soil, volcanic ash soil) for one growing season. All tree species were grown with 3 replications per each plot at elevated O3 (about 80 ppb) and ambient condition (O3 ranging 25-35 ppb). Leaf samples were taken from the top part of seedlings during the growing season in mid-September, and senescing leaves were sampled in mid-November. Both were collected for chemical composition analysis. Retranslocation rate of P was markedly increased by eO3 in birch and significantly differed among soil types in oak seedlings, while was constant across treatments in beech seedlings. Retranslocation of N in oak seedlings was significantly affected by soil type. Retranslocation of other elements was most sensitive to both eO3 and soil type in beech seedlings. The influence of differential growth patterns among species in modulating the physiological response of seedlings to high levels of ozone and different soil conditions are discussed.

Keywords: Retranslocation, Foliar Nutrients, Ozone, Volcanic Ash Soil, Serpentine Soil

iForest 9 (5): 835-841 (2016) - doi: 10.3832/ifor1889-009
https://iforest.sisef.org/contents/?id=ifor1889-009

Research Articles: Differences in early dynamics and effects of slope aspect between naturally regenerated and planted Pinus sylvestris woodland on inland dunes in Poland

Sewerniak P — 2016-06-17

Sewerniak P

DIFFERENCES IN EARLY DYNAMICS AND EFFECTS OF SLOPE ASPECT BETWEEN NATURALLY REGENERATED AND PLANTED PINUS SYLVESTRIS WOODLAND ON INLAND DUNES IN POLAND

Abstract: There is little knowledge of the effects of landform relief on early growth dynamics and competitive interactions of Pinus sylvestris (Scots pine) stands on inland dunes, which could potentially be substantial. The goal of this study was to examine and compare early dynamics (based on growth parameters and properties of the understorey vegetation) and the effects of slope aspect in naturally regenerated and pine-planted woodland on inland dunes in northern Poland. Growth parameters, tree density, and understorey vegetation were monitored on north- and south-facing slopes in a 26.3 ha post-fire area with natural secondary succession and eight even-aged pine-planted stands, 5-34 years old. Clear differences were detected between the woodland types, in both growth parameters of pines with similar ages and effects of slope aspect on the pines. In the natural regeneration area north-facing slopes provided favorable conditions for natural encroachment by pines. Tree density was higher, and the pines were taller and thicker, on north-facing than on south-facing slopes. In contrast, in the pine-planted area pines were larger on south-facing slopes, although growth conditions were less favorable than on north-facing slopes. However, in the pine-planted area the north-facing slopes had significantly higher herb cover, dominated by Deschampsia flexuosa, indicating that even the presence of a relatively low grass species can impede early growth of Scots pine. The understorey species composition differed in the natural regeneration area, being dominated by Calluna vulgaris on north-facing slopes and Corynephorus canescens on south-facing slopes. The results reveal that interactions between landform, natural dynamics, planting practices, and competitive interactions in woodlands on inland dunes are complex, and should be considered in efforts to manage them efficiently.

Keywords: Scots Pine, Growth Dynamics, Dunes, Slope Aspect, Forest Succession, Pine Plantations, Sandy Areas, Podzols

iForest 9 (6): 875-882 (2016) - doi: 10.3832/ifor1728-009
https://iforest.sisef.org/contents/?id=ifor1728-009

Technical Reports: Hot spot maps of forest presence in the Mediterranean basin

Noce S, Collalti A, Valentini R, Santini M — 2016-06-13

Noce S, Collalti A, Valentini R, Santini M

HOT SPOT MAPS OF FOREST PRESENCE IN THE MEDITERRANEAN BASIN

Abstract: The Mediterranean basin is one of the most varied areas worldwide in terms of biodiversity and species richness due to its climatic and geomorphological features, and it is characterized by multi-faceted habitats where forests play a crucial role. Nowadays, the geographic distribution of forest species is well known and multiple geographic datasets are available with different spatial details. However, protection and conservation strategies need more specific information to identify areas with high conservation priority or more vulnerable to the ongoing environmental change (“hot spots”). To this purpose, tree species distribution data were investigated through hot spot analysis using Geographic Information Systems. The analysis was carried out on presence data of ten relevant forest tree species/classes across Mediterranean Europe. By combining spatial analysis and spatial statistics, we identified high and very high hot spot areas for the selected species/classes, which were validated by assessing their biological significance. Given the sub-continental extent of the study, a multiple scale approach was applied ranging from regional, sub-regional to local scale, coherently with the potential multi-level and multi-sector users of similar data and tools. Our results confirm the feasibility of the approach used to increase the quality and quantity of information achievable from available forest distribution datasets. The hot spot maps obtained are a useful support for further spatial evaluations, and may help environmental decision makers to identify priority areas for forest protection and conservation.

Keywords: Forest, GIS, Spatial Analysis, Hot Spot, Mediterranean Basin

iForest 9 (5): 766-774 (2016) - doi: 10.3832/ifor1802-009
https://iforest.sisef.org/contents/?id=ifor1802-009

Review Papers: Genetic diversity and forest reproductive material - from seed source selection to planting

Ivetić V, Devetaković J, Nonić M, Stanković D, Šijačić-Nikolić M — 2016-06-13

Ivetić V, Devetaković J, Nonić M, Stanković D, Šijačić-Nikolić M

GENETIC DIVERSITY AND FOREST REPRODUCTIVE MATERIAL - FROM SEED SOURCE SELECTION TO PLANTING

Abstract: How much of genetic diversity is desirable in mass production of forest reproductive material? How mass production of forest reproductive material reduces genetic diversity? Relation between genetic diversity and mass production of forest reproductive material is discussed in a holistic manner. In industrial forest plantations, narrow genetic diversity is desirable and reproductive material is produced at clone level. On the other hand, in conservation forestry a wide genetic diversity is imperative. Beside management goals, a desirable level of genetic diversity is related to rotation cycle and ontogeny of tree species. Risks of failure are lower in short rotations of fast growing species. In production of slow growing species, managed in long rotations, the reduction of genetic diversity increases the risk of failure due to causes unknown or unexpected at the time of planting. This risk is additionally increased in cases of seed transfer and in conditions of climate change. Every step in production of forest reproductive material, from collection to nursery production, has an effect on genetic diversity mainly by directional selection and should be considered. This review revealed no consistent decrease of genetic diversity during forest reproductive material production and planting.

Keywords: Genetic Diversity, Forest Reproductive Material, Seed Production, Seedling Production, Directional Selection

iForest 9 (5): 801-812 (2016) - doi: 10.3832/ifor1577-009
https://iforest.sisef.org/contents/?id=ifor1577-009

Research Articles: Effects of soil compaction on seedling morphology, growth, and architecture of chestnut-leaved oak (Quercus castaneifolia)

Jourgholami M, Khoramizadeh A, Zenner EK — 2016-06-13

Jourgholami M, Khoramizadeh A, Zenner EK

EFFECTS OF SOIL COMPACTION ON SEEDLING MORPHOLOGY, GROWTH, AND ARCHITECTURE OF CHESTNUT-LEAVED OAK (QUERCUS CASTANEIFOLIA)

Abstract: Soil compaction following traffic by heavy-timber harvesting machinery usually causes an increase in soil strength, that is a stress factor negatively affecting the growth of newly germinated seedlings. This study used a soil strength experiment carried out in a greenhouse to test the hypotheses that increasing soil strength would adversely affect seedling morphology and alter seedling architecture by changing biomass allocation patterns. We explored the effects of soil compaction in a loam to clay-loam textured soil with optimal conditions of water on a continuous scale (0.2-1.0 MPa penetration resistance) on growth responses of the deciduous Quercus castaneifolia (C.A.Mey). Both above- and below-ground seedling characteristics, including size and biomass, were negatively affected by soil compaction. At the highest intensity of compaction, size and growth were reduced by 50% compared to controls; negative effects were typically more severe on below-ground (i.e., the length and biomass of the root system) than on above-ground responses. Increasing soil strength did not change above- and below-ground biomass allocation patterns (i.e., root mass ratio, root:shoot ratio, specific root length), resulting in unchanged seedling architecture. Strong adverse effects were already evident in the low-intensity compaction treatment and no critical soil strength threshold was observed. We conclude that root and height growth in Q. castaneifolia seedlings is limited by any increase of soil strength, though no evidence for the disruption of a functional equilibrium between above- and below-ground plant portions was found up to soil strengths of 1.0 MPa, at least under optimal water supply.

Keywords: Hyrcanian Forest, Penetration Resistance, Growth, Chestnut-leaved Oak, Relative Growth Rate.

iForest 10 (1): 145-153 (2017) - doi: 10.3832/ifor1724-009
https://iforest.sisef.org/contents/?id=ifor1724-009

Short Communications: Influence of thermo-vacuum treatment on bending properties of poplar rotary-cut veneer

Castro G, Rosso L, Allegretti O, Cuccui I, Cremonini C, Negro F, Zanuttini R — 2016-06-13

Castro G, Rosso L, Allegretti O, Cuccui I, Cremonini C, Negro F, Zanuttini R

INFLUENCE OF THERMO-VACUUM TREATMENT ON BENDING PROPERTIES OF POPLAR ROTARY-CUT VENEER

Abstract: The present paper investigates the influence of thermo-vacuum treatment at 170, 190 and 210 °C on the mechanical and physical properties of poplar wood rotary-cut veneers obtained from two different poplar clones (’I-214’ and ’Lena’). The modulus of rupture in bending was determined according to a method derived from European Standard EN-310 and previously validated by the authors, while the density was determined on the basis of EN-323. With both clones no significant decrease was recorded either in bending strength or in density with treatment temperatures up to 190 °C. On the contrary, at 210 °C a highly significant decrease in modulus of rupture (’I-214’: -18%; ’Lena’: -15%) was recorded; the density showed a similar, though lower, trend (’I-214’: -5 %; ’Lena’: -8.5 %).

Keywords: Populus, Poplar Wood, Veneer, Thermal treatment, Bending Strength

iForest 10 (1): 161-163 (2017) - doi: 10.3832/ifor1955-009
https://iforest.sisef.org/contents/?id=ifor1955-009

Research Articles: Modifying harvesting time as a tool to reduce nutrient export by timber extraction: a case study in planted teak (Tectona grandis L.f.) forests in Costa Rica

2016-06-03

Fernández-Moya J, Algeet-Abarquero N, Cabalceta G, Alvarado A, San Miguel-Ayanz A, Marchamalo-Sacristán M

MODIFYING HARVESTING TIME AS A TOOL TO REDUCE NUTRIENT EXPORT BY TIMBER EXTRACTION: A CASE STUDY IN PLANTED TEAK (TECTONA GRANDIS L.F.) FORESTS IN COSTA RICA

Abstract: Despite its low nutrient concentration, the high amount of biomass accumulated in the tree stem makes it an important nutrient sink. Hence, nutrient loss through timber removal at harvesting is a major cause of nutrient impoverishment at some forest sites. The present study was designed to test the following hypotheses: (a) nutrient allocation in the different tree tissues would be affected by (re)translocation processes related with leaf senescence; hence, (b) timber may have a higher nutrient concentration during the defoliated period (in deciduous species); and consequently, (c) modifying harvesting time could influence nutrient export. To test these hypotheses, the present study analyzes the intra-annual dynamics of foliar and trunk nutrient concentration in a planted teak (Tectona grandis L.f.) forest in Costa Rica. Samples from nine trees were taken at nine sampling times between June 2012 and August 2013. The results confirm the above-mentioned hypotheses and reveal that modifying harvesting time have different consequences: (1) when harvesting occurs between August and October, it reduces the N-P-K exported through timber harvesting by 24-29-43%; (2) when harvesting occurs in December, the reduction is 28-29-14%. Harvesting between August and October (rainy season) may involve logistical difficulties. Harvesting slightly earlier than usual (i.e., December, just after the rainy season but before leaf senescence) would therefore be an efficient approach to reducing nutrient export through timber extraction.

Keywords: Forest Nutrition, Soil Fertility, Soil Depletion, Sustainability, Forest Plantations, Nutrient Resorption

iForest 9 (5): 729-735 (2016) - doi: 10.3832/ifor1756-009
https://iforest.sisef.org/contents/?id=ifor1756-009

Research Articles: Linking nursery nutritional status and water availability post-planting under intense summer drought: the case of a South American Mediterranean tree species

Ovalle JF, Arellano EC, Oliet JA, Becerra P, Ginocchio R — 2016-06-03

Ovalle JF, Arellano EC, Oliet JA, Becerra P, Ginocchio R

LINKING NURSERY NUTRITIONAL STATUS AND WATER AVAILABILITY POST-PLANTING UNDER INTENSE SUMMER DROUGHT: THE CASE OF A SOUTH AMERICAN MEDITERRANEAN TREE SPECIES

Abstract: Drought-avoidance traits of South American Mediterranean tree species are crucial attributes to be considered in nursery practices aimed at improving the performance of seedlings exposed to intense summer drought in dryland reforestation projects. In this study, we determined the relation between nursery fertilization doses and the development of drought-avoidance traits of the soapbark tree Quillaja saponaria (Mol.) under contrasting watering regimes following post-planting. Seedlings were grown for 6 months using four increasing doses of controlled-release fertilizer (0, 3, 6, and 12 g L-1 of Basacote® Plus 15:8:12). After outplanting, half of the seedlings were watered weekly and the other half were left unwatered for one growing season from September 2011 to May 2012. Seedlings were periodically measured for morphological and ecophysiological parameters, and carefully harvested for root measurements at the end of the study. Our results showed that high fertilization doses produced significantly larger seedlings in the nursery with high nitrogen and phosphorous foliar concentrations, which resulted in a significantly higher shoot dry mass after outplanting. Unfertilized seedlings grown with water application had a significantly higher stem diameter, root dry mass and lower shoot/root compared with seedlings with high fertilizer dose. These results highlight the ability of this species to maintain drought-avoidance traits, such as high xylem water potential and chlorophyll fluorescence, during the first 3 months of the 7-month drought period. High nutrient loading, although resulting in improved shoot productivity after outplanting, did not make a significant contribution to the early development of drought-avoidance traits in Q. saponaria.

Keywords: Dryland Forest Restoration, Plant Quality, Root Architecture, Seedling Fertilization, Water-stress Resistance

iForest 9 (5): 758-765 (2016) - doi: 10.3832/ifor1905-009
https://iforest.sisef.org/contents/?id=ifor1905-009

Research Articles: Thinning effects on soil and microbial respiration in a coppice-originated Carpinus betulus L. stand in Turkey

Akburak S, Makineci E — 2016-05-29

Akburak S, Makineci E

THINNING EFFECTS ON SOIL AND MICROBIAL RESPIRATION IN A COPPICE-ORIGINATED CARPINUS BETULUS L. STAND IN TURKEY

Abstract: Effects of thinning on soil respiration and microbial respiration were examined over a 2-year period (2010-2012) in a coppice-originated European hornbeam (Carpinus betulus L.) stand in Istanbul, Turkey. Four plots within the stand were selected; tree density was reduced by 50% of the basal area in two plots (thinning treatment), and the other two plots served as controls. The study focused on the main factors that affect soil respiration (RS) and microbial respiration on the forest floor (RFFM) and in soil (RSM): soil temperature (TS), soil moisture (MS), soil carbon (C), soil nitrogen (N), soil pH, ground cover biomass (GC), forest floor mass (FF), forest floor carbon (FFC) and nitrogen (FFN), and fine root biomass (FRB). Every 2 months, soil respiration was measured using the soda-lime method, and microbial respiration was measured with the incubation method separately for the soil and forest floor. Results were evaluated yearly and over the 2-year research period. During the first year after treatment, RS was significantly higher (11%) in the thinned plots (1.76 g C m-2 d-1) than in the controls (1.59 g C m-2 d-1). However, there were no significant differences in either the second year or the 2-year study period. In the thinned plots during the research period, RS was linearly correlated with GC, Ts and FRB. Thinning treatments did not affect RSM, but interestingly, they did affect RFFM, which was greater in the control plots than in the thinned plots. RSM had a significant and positive correlation with soil N and soil pH, while RFFM was linearly correlated with FFC and C/N ratio of the forest floor in both thinned and control plots during the research period.

Keywords: CO2 Flux, Fine Root, Forest Floor, Ground Cover, Soil Temperature, Soil Moisture

iForest 9 (5): 783-790 (2016) - doi: 10.3832/ifor1810-009
https://iforest.sisef.org/contents/?id=ifor1810-009

Research Articles: Seasonal dynamics of soil respiration and nitrification in three subtropical plantations in southern China

Wang W, Cheng R, Shi Z, Ingwersen J, Luo D, Liu S — 2016-05-29

Wang W, Cheng R, Shi Z, Ingwersen J, Luo D, Liu S

SEASONAL DYNAMICS OF SOIL RESPIRATION AND NITRIFICATION IN THREE SUBTROPICAL PLANTATIONS IN SOUTHERN CHINA

Abstract: Numerous studies have documented that soil respiration and nitrogen cycling show a distinct seasonal dependence regulated by environmental factors (e.g., soil temperature and soil water content). The mechanisms controlling the seasonal dependence of these two key ecosystem processes have rarely been linked to both soil microbial community and soil environmental factors. Here, we present results on the seasonal patterns of soil respiration and gross nitrification rates in three subtropical plantations of Pinus massoniana, Castanopsis hystrix and Erythrophleum fordii over a period of 11 months. Turnover rates were measured with the Barometric Process Separation technique (BaPS). We elucidated how soil respiration and gross nitrification are controlled by the soil microbial community and by soil environmental factors. Soil respiration and gross nitrification showed strong seasonal dynamics, although no significant differences were observed among plantations. The turnover rates were the highest during the wet season and the lowest during the dry season. Microbial biomass, total phospholipid fatty acids (PLFAs), fungal PLFAs and bacterial PLFAs peaked during the dry season. Both soil respiration and gross nitrification rates were positively correlated with soil temperature and soil water content. Microbial biomass decreased with increasing turnover rates. Our findings highlight that carbon and nitrogen turnover rates were mostly controlled by soil temperature and soil water content.

Keywords: Soil Respiration, Nitrification, PLFA, Soil Microbial Community, N-fixing Tree Species, Subtropical China

iForest 9 (5): 813-821 (2016) - doi: 10.3832/ifor1828-009
https://iforest.sisef.org/contents/?id=ifor1828-009

Research Articles: Clonal structure and high genetic diversity at peripheral populations of Sorbus torminalis (L.) Crantz.

Jankowska-Wroblewska S, Meyza K, Sztupecka E, Kubera L, Burczyk J — 2016-05-29

Jankowska-Wroblewska S, Meyza K, Sztupecka E, Kubera L, Burczyk J

CLONAL STRUCTURE AND HIGH GENETIC DIVERSITY AT PERIPHERAL POPULATIONS OF SORBUS TORMINALIS (L.) CRANTZ.

Abstract: Knowing the level of genetic diversity and structure in marginal plant populations is essential for managing their genetic resources. This is particularly important for rare scattered tree species, such as Sorbus torminalis (L.) Crantz. We investigated the genetic diversity and its spatial distribution in peripheral populations of S. torminalis. As the species is known to reproduce vegetatively, we also evaluated clonal structure within populations. Using 13 nuclear microsatellite loci designed in two multiplexes, we genotyped 172 individuals revealing the existence of 100 distinct genotypes. Number of ramets per genotype was variable across populations with an average of 1.72. Examples of somaclonal variation at particular loci were detected. Measures of genetic diversity of the total sample were relatively high (mean allelic richness AR = 10.293; expected heterozygosity He = 0.756), as compared to other S. torminalis populations. We noticed a slightly negative inbreeding coefficient (FIS = -0.029) indicating a small excess of heterozygotes, which is typical for self-incompatible plants. Genetic differentiation among populations was low (FST = 0.048), but Bayesian clustering methods revealed the existence of three distinct genetic clusters only in part related to population structure. Significant spatial genetic structure within populations was also detected (Sp = 0.0125) indicating fine-scale pattern of isolation by distance. Our study demonstrated that peripheral populations of S. torminalis may exhibit relatively high levels of genetic diversity despite the existence of vegetative propagation. Nevertheless, if the studied or similar populations are expected to be utilized as seed sources for ex-situ or in-situ conservation purposes, the existence of clonal structure and spatial genetic structure must be taken into account in order to avoid excessive sampling of the same or closely related genets.

Keywords: Sorbus torminalis, Clonality, Range Limits, Somatic Mutations, Microsatellites

iForest 9 (6): 892-900 (2016) - doi: 10.3832/ifor1885-009
https://iforest.sisef.org/contents/?id=ifor1885-009

Research Articles: Carbon and water vapor balance in a subtropical pine plantation

Posse G, Lewczuk N, Richter K, Cristiano P — 2016-05-25

Posse G, Lewczuk N, Richter K, Cristiano P

CARBON AND WATER VAPOR BALANCE IN A SUBTROPICAL PINE PLANTATION

Abstract: Afforestation has been proposed as an effective tool for protecting primary and/or secondary forests and for mitigating atmospheric CO2. However, the dynamics of primary productivity differs between plantations and natural forests. The objective of this work was to evaluate the potential for carbon storage of a commercial pine plantation by determining its carbon balance. Measurements started when trees were aged 6 and ended when they were older than 8 years. We measured CO2 and water vapor concentrations using the Eddy covariance method. Gross primary productivity in 2010 and 2011 was 4290 ± 473 g C m-2 and 4015 ± 485 g C m-2, respectively. Ecosystem respiration ranged between 7 and 20 g C m-2 d-1, reaching peaks in all Februaries. Of the 30 months monitored, the plantation acted as carbon source for 21 months and as carbon sink for 6 months, while values close to neutrality were obtained during 3 months. The positive balance representing CO2 loss by the system was most likely due to the cut branches left on the ground following pruning activities. The plantation was subjected to pruning in January and September 2008 and to sanitary pruning in October 2010. In all cases, cut branches were not removed but remained on the ground. Residue management seems to have a very important impact on carbon balance.

Keywords: Afforestation, Carbon Source, Ecosystem Respiration, Pruning, Thinning

iForest 9 (5): 736-742 (2016) - doi: 10.3832/ifor1815-009
https://iforest.sisef.org/contents/?id=ifor1815-009

Research Articles: Assessing escapes from short rotation plantations of the invasive tree species Robinia pseudoacacia L. in Mediterranean ecosystems: a study in central Italy

Crosti R, Agrillo E, Ciccarese L, Guarino R, Paris P, Testi A — 2016-05-25

Crosti R, Agrillo E, Ciccarese L, Guarino R, Paris P, Testi A

ASSESSING ESCAPES FROM SHORT ROTATION PLANTATIONS OF THE INVASIVE TREE SPECIES ROBINIA PSEUDOACACIA L. IN MEDITERRANEAN ECOSYSTEMS: A STUDY IN CENTRAL ITALY

Abstract: Black locust (Robinia pseudoacacia L.) is a fast growing tree species native to temperate North America, and widely diffused and naturalized in Europe. It is one of the candidate species for establishing bioenergy plantations on marginal lands in temperate and sub-Mediterranean regions. This potential is in contrast to its well-known invasive habit, leading to a potential damage to plant biodiversity in many European countries. Advise against black locust plantation in regions where it is already invasive has been issued by several international reports, as well as the adoption of mitigation measures (e.g., “containment” buffer zones) to prevent the spread of the species into natural and semi-natural habitats. In the Mediterranean basin, however, no studies have been carried out aimed at quantifying the escape rate of black locust saplings from plantation stands and its recruitment into natural habitats, together with the effectiveness of a buffer zone in reducing the spread. In this study we investigated the spread of black locust along 35 transects surrounding three 20-year- old plantations and including three different land cover types: abandoned arable land, semi-natural woodland and a buffer zone (orchards) with a low degree of farming input. In addition, the effect of soil disturbance on seed propagation was investigated. Our results demonstrate that the density of black locust regeneration is strongly affected by the land cover, abandoned agricultural land being the most prone to black locust colonization. Contrastingly, the spread was minimal in the buffer zone and negligible in semi-natural woodland. During the investigated year, seed generative propagation was also negligible. The semi-natural woodland seems to resist well to black locust invasion, though further observations are needed to assess the consequences of stand harvesting disturbance as well, according to local standard forest management. Buffer zones seem to be very effective in controlling black locust invasion. Best management practices, with active farming inputs, are also discussed.

Keywords: False Acacia, Mediterranean Region, Risk Assessment, Containment, EU Regulation, Invasive Species

iForest 9 (5): 822-828 (2016) - doi: 10.3832/ifor1526-009
https://iforest.sisef.org/contents/?id=ifor1526-009

Research Articles: Predicting impacts of climate change on forest tree species of Bangladesh: evidence from threatened Dysoxylum binectariferum (Roxb.) Hook.f. ex Bedd. (Meliaceae)

Sohel SI, Akhter S, Ullah H, Haque E, Rana P — 2016-05-25

Sohel SI, Akhter S, Ullah H, Haque E, Rana P

PREDICTING IMPACTS OF CLIMATE CHANGE ON FOREST TREE SPECIES OF BANGLADESH: EVIDENCE FROM THREATENED DYSOXYLUM BINECTARIFERUM (ROXB.) HOOK.F. EX BEDD. (MELIACEAE)

Abstract: The impact of climate change on ecosystems, especially at the species level, can be currently observed in many parts of the world. Species distribution models (SDMs) are widely used to predict the likely changes in the distribution of species in future climate change scenarios. The aim of the present study is to predict the effect of climate change on a valuable threatened tree species Dysoxylum binectariferum in the northeastern part of Bangladesh using the maximum entropy (MaxEnt) model on species’ occurrence data. The future distribution of D. binectariferum was predicted under two scenarios from the IPCC 5th assessment (RCP 4.5, and RCP 8.5) in 2050 and 2070. Model results showed that approximately 32% (2177 km2) of the studied area is currently suitable for this species to grow. However, future predictions obtained by the model projected a complete loss of suitable habitat for D. binectariferum in the studied area by both 2050 and 2070. Therefore, urgent measures are required for the conservation of D. binectariferum in northeastern Bangladesh. The application of species distribution models to simple inventory data (such as the occurrence of the species) may provide policymakers and conservationists with a useful tool for the prediction of future distribution (at both local and regional scales) of poorly known species with high preservation concerns.

Keywords: Habitat Distribution Modeling, Potential Distribution Areas, Reintroduction, MaxEnt, Conservation

iForest 10 (1): 154-160 (2017) - doi: 10.3832/ifor1608-009
https://iforest.sisef.org/contents/?id=ifor1608-009

Research Articles: Groundwater uptake of forest and agricultural land covers in regions of recharge and discharge

Móricz N, Tóth T, Balog K, Szabó A, Rasztovits E, Gribovszki Z — 2016-05-17

Móricz N, Tóth T, Balog K, Szabó A, Rasztovits E, Gribovszki Z

GROUNDWATER UPTAKE OF FOREST AND AGRICULTURAL LAND COVERS IN REGIONS OF RECHARGE AND DISCHARGE

Abstract: Groundwater uptake of vegetation in discharge regions is known to play an important role, e.g., in the Hungarian Great Plain. Nevertheless, only little detailed monitoring of water table fluctuations and groundwater uptake (ETgw) were reported under varying hydrologic conditions and vegetation cover. In this study, results of water table monitoring under forest plantations and adjacent corn plots in discharge and recharge regions were analyzed to gain better understanding of the relation of vegetation cover to groundwater uptake. A poplar (Populus tremula) plantation and adjacent corn field plot were surveyed in a local discharge area, while a black locust (Robinia pseudoacacia) plantation and adjacent corn field plot were analyzed in a recharge area. The water table under the poplar plantation displayed a night-time recovery in the discharge region, indicating significant groundwater supply. In this case an empirical version of the water table fluctuation method was used for calculating the ETgw that included the groundwater supply. The mean ETgw of the poplar plantation was 3.6 mm day-1, whereas no water table fluctuation was observed at the nearby corn plot. Naturally, the root system of the poplar was able to tap the groundwater in depths of 3.0-3.3 m while the shallower roots of the corn did not reach the groundwater reservoir in depths of 2.7-2.8 m. In the recharge zone the water table under the black locust plantation showed step-like changes referring to the lack of groundwater supply. The mean ETgw was 0.7 mm day-1 (groundwater depths of 3.0-3.2 m) and similarly no ETgw was detected at the adjacent corn plot with groundwater depths between 3.2 and 3.4 m. The low ETgw of the young black locust plantation was due to the lack of groundwater supply in recharge area, but also the shallow root system might have played a role. Our results suggest that considerations should be given to local estimations of ETgw from water table measurements that could assist to better understanding of groundwater use of varying vegetation types in recharge and discharge zones.

Keywords: Groundwater, Evapotranspiration, Poplar, Black Locust, Recharge and Discharge Area

iForest 9 (5): 696-701 (2016) - doi: 10.3832/ifor1864-009
https://iforest.sisef.org/contents/?id=ifor1864-009

Research Articles: Modelling diameter distribution of Tetraclinis articulata in Tunisia using normal and Weibull distributions with parameters depending on stand variables

Sghaier T, Cañellas I, Calama R, Sánchez-González M — 2016-05-17

Sghaier T, Cañellas I, Calama R, Sánchez-González M

MODELLING DIAMETER DISTRIBUTION OF TETRACLINIS ARTICULATA IN TUNISIA USING NORMAL AND WEIBULL DISTRIBUTIONS WITH PARAMETERS DEPENDING ON STAND VARIABLES

Abstract: The objective of this study was to evaluate the effectiveness of both Normal and two-parameter Weibull distributions in describing diameter distribution of Tetraclinis articulata stands in north-east Tunisia. The parameters of the Weibull function were estimated using the moments method and maximum likelihood approaches. The data used in this study came from temporary plots. The three diameter distribution models were compared firstly by estimating the parameters of the distribution directly from individual tree measurements taken in each plot (parameter estimation method), and secondly by predicting the same parameters from stand variables (parameter prediction method). The comparison was based on bias, mean absolute error, mean square error and the Reynolds’ index error (as a percentage). On the basis of the parameter estimation method, the Normal distribution gave slightly better results, whereas the Weibull distribution with the maximum likelihood approach gave the best results for the parameter prediction method. Hence, in the latter case, the Weibull distribution with the maximum likelihood approach appears to be the most suitable to estimate the parameters for reducing the different comparison criteria for the distribution of trees by diameter class in Tetraclinis articulata forests in Tunisia.

Keywords: Diameter Class Model, Normal Distribution, Weibull Distribution, Maximum Likelihood Approach, Moments Method, Tetraclinis articulata

iForest 9 (5): 702-709 (2016) - doi: 10.3832/ifor1688-008
https://iforest.sisef.org/contents/?id=ifor1688-008

Research Articles: An overview of Italian participation in afforestation and reforestation projects under the Clean Development Mechanism

Corradini G, Brotto L, Ciccarese L, Pettenella D — 2016-05-17

Corradini G, Brotto L, Ciccarese L, Pettenella D

AN OVERVIEW OF ITALIAN PARTICIPATION IN AFFORESTATION AND REFORESTATION PROJECTS UNDER THE CLEAN DEVELOPMENT MECHANISM

Abstract: In order to meet its Kyoto Protocol commitment targets, the Italian Government has made relevant investments in forest projects in developing countries through the Clean Development Mechanism. This paper investigates the Italian participated afforestation/reforestation (A/R) projects under the Clean Development Mechanism of the Kyoto Protocol, by considering the countries hosting forestry projects, the project areas, the estimated emission reductions, the use of tree species (native/non-native), the issuance of Carbon credits, and the projects’ contribution to sustainable development and technology transfer in general, as stated by the “Project Design Document” of each project. This study utilizes the “Project Design Documents” and “Monitoring Reports” of the registered projects in the United Nations Convention on Climate Change database and data from the BioCarbon Fund database. Results show that, in terms of number of projects, the A/R sector is a prominent component of the Italian CDM portfolio. The financing of the 16 projects by the Italian government, with a total of about 65 k ha planted and an estimated emission reductions of about 556 k tCO2 eq per year, are based on criteria that differ substantially from the ongoing policy adopted for domestic forest interventions.

Keywords: CDM, Afforestation, Reforestation, Italy, Forest Policy, Impact Analysis

iForest 9 (5): 720-728 (2016) - doi: 10.3832/ifor1654-009
https://iforest.sisef.org/contents/?id=ifor1654-009

Research Articles: Calibration of a multi-species model for chlorophyll estimation in seedlings of Neotropical tree species using hand-held leaf absorbance meters and spectral reflectance

Viera Silva D, Dos Anjos L, Brito-Rocha E, Dalmolin AC, Mielke MS — 2016-05-17

Viera Silva D, Dos Anjos L, Brito-Rocha E, Dalmolin AC, Mielke MS

CALIBRATION OF A MULTI-SPECIES MODEL FOR CHLOROPHYLL ESTIMATION IN SEEDLINGS OF NEOTROPICAL TREE SPECIES USING HAND-HELD LEAF ABSORBANCE METERS AND SPECTRAL REFLECTANCE

Abstract: The aim of the present study was to calibrate a multi-species model for assessing leaf chlorophyll content in seedlings of six Neotropical rainforest tree species. Two hand-held chlorophyll absorbance meters (SPAD-502 and ClorofiLog) and the chlorophyll normalized difference leaf reflectance index (ND705) were tested. Measurements of leaf absorbance and reflectance, contents of chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll (Chl t), leaf area (LA), and leaf mass per area (LMA) were performed on fully expanded leaves. A total of 200 leaves were used for the calibration of the multiple-species model. The relative root mean square calibration errors (RMSεc, %) were calculated based on estimated chlorophyll values for multiple-species models and on measured values for each of the six species. The average values of LA varied between 14.2 and 29.5 cm-2, LMA between 34.8 and 98.9 g m-2, and Chl t between 3 and 815 mg m-2. For all indices, the highest values of the coefficients of determination (R2) were observed for Chl a (R2 ≥ 0.91), followed by Chl t (R2 ≥ 0.89) and Chl b (R2 ≥ 0.82). The highest values of R2 were obtained for ND705 (R2 ≥ 0.86) followed by SPAD-502 (R2 ≥ 0.83) and ClorofiLog (R2 ≥ 0.82). The present study showed that ClorofiLog and SPAD-502 indices could be safely interconverted by a simple linear regression model (R2 = 0.98). RMSεc values were lower than 20%, which confirmed the feasibility of the multi-species model for estimating the chlorophyll content using hand-held chlorophyll absorbance meters and leaf reflectance.

Keywords: Chlorophyll Normalized Difference Index, Hand-held Chlorophyll Absorbance Meters, Leaf Reflectance, Neotropical Tree Species

iForest 9 (5): 829-834 (2016) - doi: 10.3832/ifor1785-009
https://iforest.sisef.org/contents/?id=ifor1785-009

Research Articles: Integrating conservation objectives into forest management: coppice management and forest habitats in Natura 2000 sites

2016-05-12

Mairota P, Buckley P, Suchomel C, Heinsoo K, Verheyen K, Hédl R, Terzuolo PG, Sindaco R, Carpanelli A

INTEGRATING CONSERVATION OBJECTIVES INTO FOREST MANAGEMENT: COPPICE MANAGEMENT AND FOREST HABITATS IN NATURA 2000 SITES

Abstract: Most forest habitats, as defined and listed for their nature conservation importance in the Habitats Directive of the European Union and in the Bern Convention, result from centuries of human intervention. This paper explores the scope for, and the attitudes towards coppicing in Natura 2000 sites in some of the EU28 countries where coppice was historically one of the most important traditional silvicultural systems. A questionnaire survey was circulated to experts involved with Natura 2000 sites and case studies were conducted in Belgium, the Czech Republic, Estonia, Germany, Italy and the United Kingdom, to investigate attitudes to coppice silviculture within the framework of Natura 2000 site management plans. A list of forest habitat types capable of being managed as coppices was compiled and populated with sites at national and regional levels. At the regional level, management plans for the relevant forest habitat types in Natura 2000 sites were critically scrutinised together with other statutory, administrative or contractual measures. The results show that approaches to integrate coppice management into conservation plans differ widely. Examples of disparities are given and the possible causes discussed. A case is made for coppicing to be continued, where appropriate, as an important strategy in site management plans that aim to conserve habitats and improve forest biodiversity.

Keywords: Habitats Directive, Natura 2000, Forest Habitat Types, Coppice, Biodiversity, Landscape

iForest 9 (4): 560-568 (2016) - doi: 10.3832/ifor1867-009
https://iforest.sisef.org/contents/?id=ifor1867-009

Research Articles: A comparative study of four approaches to assess phenology of Populus in a short-rotation coppice culture

2016-05-12

Vanbeveren SP, Bloemen J, Balzarolo M, Broeckx LS, Sarzi-Falchi I, Verlinden MS, Ceulemans R

A COMPARATIVE STUDY OF FOUR APPROACHES TO ASSESS PHENOLOGY OF POPULUS IN A SHORT-ROTATION COPPICE CULTURE

Abstract: We compared four approaches to assess phenology in a short-rotation coppice culture with 12 poplar (Populus) genotypes. The four approaches quantified phenology at different spatial scales and with different temporal resolutions: (i) visual observations of bud phenology; (ii) measurements of leaf area index; (iii) webcam images; and (iv) satellite images. For validation purposes we applied the four approaches during two years: the year preceding a coppice event and the year following the coppice event. The delayed spring greenup and the faster canopy development in the year after coppicing (as compared to the year before coppicing) were similarly quantified by the four approaches. The four approaches detected very similar seasonal changes in phenology, although they had different spatial scales and a different temporal resolution. The onset of autumn senescence after coppicing remained the same as in the year before coppicing according to the bud set observations, but it started earlier according to the webcam images, and later according to the MODIS images. In comparison to the year before coppicing, the growing season - in terms of leaf area duration - was shorter in the year after coppicing, while the leaf area index was higher.

Keywords: ExG Index, Leaf Area Index, MODIS, NDVI, WRDVI, POPFULL

iForest 9 (5): 682-689 (2016) - doi: 10.3832/ifor1800-009
https://iforest.sisef.org/contents/?id=ifor1800-009

Research Articles: Effect of seedling stock on the early stand development and physiology of improved loblolly pine (Pinus taeda L.) seedlings

Sharma S, Adams JP, Schuler JL, Ficklin RL, Bragg DC — 2016-05-12

Sharma S, Adams JP, Schuler JL, Ficklin RL, Bragg DC

EFFECT OF SEEDLING STOCK ON THE EARLY STAND DEVELOPMENT AND PHYSIOLOGY OF IMPROVED LOBLOLLY PINE (PINUS TAEDA L.) SEEDLINGS

Abstract: This study assessed the effects of spacing and genotype on the growth and physiology of improved loblolly pine (Pinus taeda L.) seedlings from three distinct genotypes planted in Drew County, Arkansas (USA). Genotype had a significant effect on survival and height. Clone CF Var 1 showed greater height and survival compared to other seedlings. Genotype had significant effects on uniformity in height both years and ground line diameter (GLD) first year. However, genotype had no significant effects on leaf water potential and coefficient variation of leaf water potential. These growth and physiology should be further studied to assess potential genetic differences among seedlings and to determine if they can be identified early for improved growth at later ages.

Keywords: Loblolly Pine, Genotype, Leaf Water Potential, Coefficient of Variation

iForest 9 (5): 690-695 (2016) - doi: 10.3832/ifor1725-009
https://iforest.sisef.org/contents/?id=ifor1725-009

Research Articles: Discovering interaction between oaks and carabid beetles on a local scale by point pattern analysis

Wagner S, Wehnert A, Wong KY, Stoyan D — 2016-05-06

Wagner S, Wehnert A, Wong KY, Stoyan D

DISCOVERING INTERACTION BETWEEN OAKS AND CARABID BEETLES ON A LOCAL SCALE BY POINT PATTERN ANALYSIS

Abstract: The understanding of habitat demands of single species needs an explicit habitat element approach which includes both the effect of intensity of the habitat element on the species population and the spatial effect of that habitat element in a given matrix (e.g., forest or water). An established tool in ecological research for this purpose is the point pattern analysis, which yields information on relationships between organisms and habitat elements, as well as on interactions among individuals. However, the application of this tool seems to be restricted so far to locally fixed species and habitat elements. As our model system consists of carabid beetles and single old oak trees in a Scots pine forest, we needed to address the issue of fauna mobility in point pattern analysis. We adopted a random field approach to transform the lattice beetle traps data to point data. For the resulting bivariate point pattern we applied the toroidal shift test to verify the independence of tree and beetle distribution. To overcome the problem of irregular window shape, we reconstructed the oak data to obtain a point pattern in a larger rectangular window to make toroidal shifts possible. We could justify a positive spatial association between oak tree and carabid beetle distributions. By our results, specific spatial fields of oak influence on the beetle species can be derived which may allow for beetles supporting management measures like an increase of oak tree proportion and a more regular spatial distribution of single admixed oak trees. Those measures may increase the ecological effect of C. coriaceus as an antagonist for pest insects in mono-cultured Scots pine forests.

Keywords: Point Pattern Analysis, Species Association, Toroidal Shift Test

iForest 9 (4): 618-625 (2016) - doi: 10.3832/ifor1952-009
https://iforest.sisef.org/contents/?id=ifor1952-009

Research Articles: Carbon storage and soil property changes following afforestation in mountain ecosystems of the Western Rhodopes, Bulgaria

Zhiyanski M, Glushkova M, Ferezliev A, Menichetti L, Leifeld J — 2016-05-06

Zhiyanski M, Glushkova M, Ferezliev A, Menichetti L, Leifeld J

CARBON STORAGE AND SOIL PROPERTY CHANGES FOLLOWING AFFORESTATION IN MOUNTAIN ECOSYSTEMS OF THE WESTERN RHODOPES, BULGARIA

Abstract: Land-use changes and afforestation activities are widely recognized as possible measures for mitigating climate change through carbon sequestration. The present study was conducted to evaluate the effect of afforestation on (i) soil physical and chemical properties and soil carbon stocks in four mountain ecosystems and (ii) whole ecosystem carbon storage. The four experimental sites, situated in the Western Rhodope Mountains (Bulgaria) were characterized by typical forest-related land-use conversions. The four sites were a Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) plantation (Rd1) established on former cropland, a mixed black pine (Pinus nigra Arn.) with Scots pine (Pinus sylvestris L.) plantation (Rd2) established on former cropland, a cropland (RdA1) and an abandoned land with uncontrolled extensive grazing (RdA2) historically used as cropland. Soil parameters, i.e., sand content, pH, organic C and N contents, C/N ratio and soil organic carbon (SOC) stocks, were significantly affected by land use and land-use history. Conversion from cropland into forestland significantly reduced soil bulk density and coarse fragments at 0-10 cm depth. Compared with adjacent cropland and abandoned land, soils in coniferous plantations were acidified in their upper layers. Sites Rd2 and RdA2 contained the least SOC owing to the previous long-term arable cultivation (>100 years). Analysis of the ecosystem C stock distribution revealed that most of C in forests was stored in the aboveground tree biomass. Our study confirmed that afforestation of cropland turned the soil into a C sink for the selected mountain region, but showed conflicting results when afforestation occurred on abandoned cropland.

Keywords: Land-use Change, Afforestation, Soil, Forest Floor, Biomass, Carbon Stock

iForest 9 (4): 626-634 (2016) - doi: 10.3832/ifor1866-008
https://iforest.sisef.org/contents/?id=ifor1866-008

Research Articles: Comparison of drought stress indices in beech forests: a modelling study

Vilhar U — 2016-05-06

Vilhar U

COMPARISON OF DROUGHT STRESS INDICES IN BEECH FORESTS: A MODELLING STUDY

Abstract: Two drought stress indices were applied to managed as well as old-growth beech forests and gaps for the 2001 to 2013 period to aid in the development of an efficient tool for field water supply diagnosis. The relative extractable soil water (REW), which was calculated from the soil water content in the root zone, and the transpiration index (TI), calculated as the ratio between the actual and potential transpiration were used. Both indices were calculated on a daily basis using the water balance model BROOK90, which was fitted and tested using measured data on throughfall and soil water content. A sensitivity analysis apportioned to the input parameters of the drought stress indices was conducted to assess uncertainty. Both drought stress indices showed the greatest drought stress in the years 2009, 2003 and 2011, as also indicated by the Standardized Precipitation Evapotranspiration Index (SPEI) at the nearest meteorological station. However, drought stress intensity and duration differed between the indices and study sites. Greater water supply stress was shown in the forests than the gaps. Furthermore, the agreement among the indices was smaller for gaps compared with forests, which implies that careful index selection is needed when comparing water supply stresses in different stages of forest stand development. Due to the low amount of input data required and the parameters that can be measured with relative ease in the field, REW might be an efficient tool for field water supply diagnosis when analyzing the drought stresses of similar forest types and at unique stages of development. REW satisfactorily indicated drought stress in forests but to a lesser extent in gaps. TI demonstrated more consistent differences in drought stress between forests and gaps and therefore proved to be the appropriate index for a detailed analysis of drought stress variation between different stages of forest stand development. However, due to a greater number of required input data and more demanding parameters, TI appears to be a more complex tool than REW for field water supply diagnosis in forests.

Keywords: Relative Extractable Soil Water, Transpiration Index, Standardized Precipitation Evapotranspiration Index, Fagus sylvatica, BROOK90 Model, Managed Forest, Old-growth Forest, Canopy Gap

iForest 9 (4): 635-642 (2016) - doi: 10.3832/ifor1630-008
https://iforest.sisef.org/contents/?id=ifor1630-008

Research Articles: Influence of tree water potential in inducing flowering in Rhododendron arboreum in the central Himalayan region

Tewari A, Bhatt J, Mittal A — 2016-05-06

Tewari A, Bhatt J, Mittal A

INFLUENCE OF TREE WATER POTENTIAL IN INDUCING FLOWERING IN RHODODENDRON ARBOREUM IN THE CENTRAL HIMALAYAN REGION

Abstract: Rise in temperature has been reported as the principal cause of variation in flowering phenology in several tree species around the globe. In this study, we hypothesized that not only temperature but also rainfall periodicity, soil moisture and the related changes of twig water potential (ψ) in winter and early spring are important drivers of bud expansion and flowering in Rhododendron arboreum in central Himalayas. To this purpose, phenological and physiological variables (flowering time, flower bud size and twig water potential) were monitored over two years in a wild population of R. arboreum (Uttarakhand, India) and related with environmental variables (rainfall, soil moisture and temperature). Results showed that a rise in twig ψ to -0.7MPa, one week after moderate winter precipitation resulted in flower bud enlargement. In both years flowering was triggered after twig ψ reached the threshold of -0.5 Mpa, though the starting date differed between years. Floral bud size was correlated positively with twig ψ (r = 0.43, df =162, p < 0.001) and soil moisture (r = 0.61, df = 71, p < 0.001), while temperature did not influence flower bud size, soil moisture and twig ψ. Flower bud size increment was related with increase in twig ψ and soil moisture. Based on our results, we concluded that water availability plays an important role in inducing flowering in R. arboreum.

Keywords: Rhododendron, Global Warming, Flowering, Water Potential, Himalaya

iForest 9 (5): 842-846 (2016) - doi: 10.3832/ifor1525-008
https://iforest.sisef.org/contents/?id=ifor1525-008

Research Articles: The impact of seed predation and browsing on natural sessile oak regeneration under different light conditions in an over-aged coppice stand

2016-04-04

Kamler J, Dobrovolný L, Drimaj J, Kadavý J, Kneifl M, Adamec Z, Knott R, Martiník A, Plhal R, Zeman J, Hrbek J

THE IMPACT OF SEED PREDATION AND BROWSING ON NATURAL SESSILE OAK REGENERATION UNDER DIFFERENT LIGHT CONDITIONS IN AN OVER-AGED COPPICE STAND

Abstract: Sessile oak (Quercus petraea (Matt.) Liebl.) is one of the most important commercial species cultivated at low altitudes in the Czech Republic, and over-aged coppices are a significant part of oak stands in the region. In order to secure a high-valuable timber production (e.g., through conversion of such stands into coppices-with-standards), knowledge of the potential and limits of generative regeneration is essential. This study was conducted in three oak-dominated over-aged coppice stands in different stages of conversion into coppices-with-standards and characterized by different basal area (BA, from 9.3 to 14.1 m2 ha-1) and relative diffuse radiation (ISF, from 12.1 to 35.5%). The study stands were compared with respect to seed predation following acorn fall and oak regeneration parameters. At the time of their fall the acorns represented a sought-after source of food for large mammals (particularly wild boar). At the end of acorn fall, 13-67% acorns were lost due to animal predation. A control evaluation conducted the following spring revealed a decrease of 92-97% in fallen acorns. Despite the major animal impact, a high reserve of acorns and saplings remained in the stands (4 600-29 000 acorns and 66 000-310 000 saplings per ha). With increasing light intensity the oak regeneration density decreased, while the height and age variability of oak regeneration increased. Although saplings were capable of surviving several years under unfavorable light conditions (even below 12% ISF), they require a minimum of 20% ISF (i.e., BA < 16 m2 ha-1) to achieve sustainable height increment. Based on our results, for conversion of such stands into coppices-with-standards we recommend a maximum of 200 reserved trees (BA = 16 m2 ha-1) to achieve successful height growth of the understorey.

Keywords: Over-aged Coppice, Quercus petraea, Natural Regeneration, Herbivore Impact, Acorn, Light Intensity, Wild Boar

iForest 9 (4): 569-576 (2016) - doi: 10.3832/ifor1835-009
https://iforest.sisef.org/contents/?id=ifor1835-009

Research Articles: Traditional coppice in South East England: the importance of workforce engagement for development

Bartlett D — 2016-04-04

Bartlett D

TRADITIONAL COPPICE IN SOUTH EAST ENGLAND: THE IMPORTANCE OF WORKFORCE ENGAGEMENT FOR DEVELOPMENT

Abstract: This paper describes research into the historic importance of the coppice industry, now largely restricted to south east England and the relevance of this to current rural development policy. The economic and social contexts have altered significantly over time with product substitution and changing consumer aspirations, and particularly the availability of alternative fuel sources. Over the last fifty years the “value” attached to coppiced woodlands has shifted away from resource exploitation and towards a greater appreciation of them for wildlife, recreation, amenity and cultural heritage. This has increased wider public awareness of and appreciation for coppicing as a management technique and, consequently rising concern over the reduction in area managed. This was assumed to be due to market failure but attempts to reverse this by creating new outlets failed. The reason for this has been explored by engaging directly with the workforce, both individually and in focus groups. Coppice workers were found to be more numerous, active and enterprising than previously thought, and many were found to be working in family groups servicing traditional markets. They were unaware of concerns about decline in the area coppiced or initiatives to address it. Issues currently affecting their businesses included housing costs, rural crime, harvesting restrictions, loss of yards and training needs. It is concluded that Government policies to promote woodfuel are not likely to succeed without active engagement with the workforce to understand their perspectives and enabling them to participate in policy decisions is recommended.

Keywords: Chestnut, Workforce, Development, Policy

iForest 9 (4): 577-582 (2016) - doi: 10.3832/ifor1809-009
https://iforest.sisef.org/contents/?id=ifor1809-009

Research Articles: Individual tree mortality of silver birch (Betula pendula Roth) in Estonia

Maleki K, Kiviste A — 2016-04-04

Maleki K, Kiviste A

INDIVIDUAL TREE MORTALITY OF SILVER BIRCH (BETULA PENDULA ROTH) IN ESTONIA

Abstract: The functioning of complex forest ecosystems is intimately related to their structural properties. Tree mortality is a major driver of forest stand dynamics and therefore plays an important role in the formation of forest structure. Data from the Estonian Network of Forest Research Plots (ENFRP) was used to estimate the mortality probability of silver birch trees (Betula pendula Roth) by using logistic models. In this study several spatial and non-spatial variables were tested to determine the most important mortality explanatory factors. Additionally, thinning variables were defined and implemented into the mortality models, to examine whether thinning practices could modify the stand structure and density, then leading to a lower mortality rate. The results of this study showed that tree mortality models that included either a five-year diameter growth rate (id5) as a measure of tree vitality, or the tree relative diameter (drel) as a measure of competition, or both these two variables, were substantially better than any models not including these variables. In addition, any measures of spatial aggregation (agg) and species proportion (sp) within the zone of influence markedly improved the model predictions, though the mortality probability of trees declined where there was higher aggregation and species mixture. Our results also suggested that if thinning were conducted around the birch trees, depending on the thinning intensity, the number of neighbors is effectively reduced, and consequently the competition load within the influence zone decreases, leading to healthier growth and lower mortality rates of the shade-intolerant birch trees. We thus recommend to adopt thinning regimes in mixed forest stands to foster tree species diversity, and at the same time provide adequate growing space for birch trees within the stands. This will improve the forest structure and increase the adaptive capacity of forests, which is increasingly important under changing climatic conditions.

Keywords: Betula pendula Roth, Diameter Growth, Species Proportion, Aggregation, Competition

iForest 9 (4): 643-651 (2016) - doi: 10.3832/ifor1672-008
https://iforest.sisef.org/contents/?id=ifor1672-008

Research Articles: The effect of seed size on seed fate in a subtropical forest, southwest of China

Lang Z, Wang B — 2016-04-04

Lang Z, Wang B

THE EFFECT OF SEED SIZE ON SEED FATE IN A SUBTROPICAL FOREST, SOUTHWEST OF CHINA

Abstract: Scatter-hoarding rodents acting both as seed predators and dispersers usually play an important role in seed dispersal of many plant species. Seed size is thought to essentially affect rodent scatter-hoarding processes. However, studies to date have frequently shown many controversial results regarding the effect of seed size on rodent foraging. In this study, we explored how seed size affects scatter-hoarding rodent foraging preferences in order to identify the possible reasons underlying the conflicting results reported in the scientific literature. We surveyed rodent seed predation and dispersal of five common tree species in a natural subtropical forest located in southwestern China along two seasons which were different in both seed abundances and rodent communities. Our results showed that a similar effect of seed size on rodent scatter-hoarding behavior existed in both seasons, although the seeds in spring were harvested more quickly than in autumn. Larger seeds of the small-seeded species (Castanopsis wattii, Lithocarpus hancei, Machilns yunnanensis and Lithocarpus pachyphyllus) were harvested, removed, and finally cached by the rodents more frequently. For the largest-seeded species (Lithocarpus xylocarpus), seeds with smaller size were preferred during the rodent scatter-hoarding processes. Our findings support the hypothesis that scatter-hoarding rodents preferably feed on large seeds at early stage of seed dispersal, but only up to a certain threshold of seed size.

Keywords: Cache, Rodents, Seed Dispersal, Seed Predation, Seed Size

iForest 9 (4): 652-657 (2016) - doi: 10.3832/ifor1852-008
https://iforest.sisef.org/contents/?id=ifor1852-008

Research Articles: Saproxylic beetles in non-intervention and coppice-with-standards restoration management in Meerdaal forest (Belgium): an exploratory analysis

Vandekerkhove K, Thomaes A, Crèvecoeur L, De Keersmaeker L, Leyman A, Köhler F — 2016-03-25

Vandekerkhove K, Thomaes A, Crèvecoeur L, De Keersmaeker L, Leyman A, Köhler F

SAPROXYLIC BEETLES IN NON-INTERVENTION AND COPPICE-WITH-STANDARDS RESTORATION MANAGEMENT IN MEERDAAL FOREST (BELGIUM): AN EXPLORATORY ANALYSIS

Abstract: For many centuries, coppice-with-standards management was applied in the mixed oak stands of Meerdaal forest (Belgium). Over the last century, these stands were gradually converted to high forest. On an area of 20 ha, the coppice-with-standards management is being restored, with specific adaptations for biodiversity (conservation of dead wood and veteran trees). A survey of saproxylic beetles was performed at 8 locations in the forest, including one site within the coppice-with-standards restoration. This survey not only allowed an evaluation of the saproxylic beetle richness of the forest complex, but also made exploratory observations on the effect of this type of management, as compared to non-intervention, on species richness and composition of saproxylic beetles. The results show that the overall species richness in the forest complex was quite high and comparable to forest reserves in Germany. Both coppice-with-standards and high forest options appear to be equally species-rich, but consist of different communities, both containing specific, rare and notable species, with more thermophilous and light-demanding species in the coppice-with-standards plot. Based on these observations we suggest that a diversified management approach may be the most suitable to conserve and enhance diverse saproxylic beetle communities in formerly intensively managed semi-natural woodlands. This could include areas of active conservation management aimed at producing open-canopy stands with considerable amounts of sun-exposed deadwood, combined with areas of non-intervention in a matrix of multifunctional forests, where conservation of dead wood and veteran trees is fully incorporated in the management.

Keywords: Coppice-with-standards, Saproxylic Beetles, Insect Biodiversity, Type of Management, Active Conservation Management

iForest 9 (4): 536-545 (2016) - doi: 10.3832/ifor1841-009
https://iforest.sisef.org/contents/?id=ifor1841-009

Research Articles: Different harvest intensity and soil CO2 efflux in sessile oak coppice forests

Darenova E, Cater M, Pavelka M — 2016-03-25

Darenova E, Cater M, Pavelka M

DIFFERENT HARVEST INTENSITY AND SOIL CO2 EFFLUX IN SESSILE OAK COPPICE FORESTS

Abstract: Soil CO2 efflux accounts for about 45-80% of total ecosystem respiration and is therefore an important part of the ecosystem carbon cycle. Soil CO2 efflux has been poorly studied in forests managed in the ancient coppicing manner. In our study, soil CO2 efflux, temperature, and moisture were measured in sessile oak stands with different harvesting intensity (control: 0% intensity; V1: 75%; V2: 80 %; V3: 85%; and V4: 100%) during the fifth and sixth years after harvesting. Soil CO2 efflux was in the range 2-8 µmol CO2 m-2 s-1 and indicated an increasing pattern with increasing harvesting intensity. The slope of that pattern became less steep from the fifth to the sixth year after harvesting, thus indicating gradual recovery of soil carbon dynamics in the coppiced stand toward the equilibrium state existing before harvesting. Temperature sensitivity of soil CO2 efflux ranged between 2.1 and 2.8, with the lowest values measured in the control stand. Soil CO2 efflux in the control stand was more sensitive to changes in soil moisture than was that on harvested plots. By our calculations, 6.2 tC ha-1 was released from the control stand and 6.2-6.8 tC ha-1 from the harvested stands during the sixth year after harvesting. If mean temperature were to rise by 1 °C, the amount of soil carbon released would increase by 7.7% in the control stand and, depending on harvesting intensity, by 9.0-10.8% in the harvested stands.

Keywords: Low Forest, Soil Moisture, Soil Respiration, Temperature Dependence

iForest 9 (4): 546-552 (2016) - doi: 10.3832/ifor1773-009
https://iforest.sisef.org/contents/?id=ifor1773-009

Research Articles: Comparison of assimilation parameters of coppiced and non-coppiced sessile oaks

Holišová P, Pietras J, Darenová E, Novosadová K, Pokorný R — 2016-03-25

Holišová P, Pietras J, Darenová E, Novosadová K, Pokorný R

COMPARISON OF ASSIMILATION PARAMETERS OF COPPICED AND NON-COPPICED SESSILE OAKS

Abstract: Coppice forest is an alternative to high forest mainly aimed at the production of firewood with a short rotation period. A new interest in this silvicultural system has arisen with the demand for renewable energy resources. Exploiting the existing root system of the stump, sprouts are advantaged over plants of seed origin, and this advantage could induce changes at the level of a photosynthetic apparatus, especially in young plants. This paper presents a comparison of the photosynthetic ability of young sprouts, young seedlings and mature trees of sessile oak (Quercus petraea (Matt.) Liebl.) growing in a forest stand managed as a coppice-with-standards in the southeast of the Czech Republic. The basic photosynthetic characteristics and transpiration rate at the leaf level were determined using gas-exchange measurement techniques. Data taken in non-limiting conditions were compared with those obtained under limiting soil moisture. The results revealed no differences between the measured parameters of sprouts, seedlings and old trees in non-limiting conditions. Contrastingly, sprouts had the highest photosynthetic capacity and transpiration during drought due to their ability to maintain a higher stomatal conductance as compared with seedlings and old trees. This suggests a better drought tolerance of sprouts compared to seedlings.

Keywords: Drought, Photosynthesis, Sprouts, Seedlings

iForest 9 (4): 553-559 (2016) - doi: 10.3832/ifor1824-009
https://iforest.sisef.org/contents/?id=ifor1824-009

Research Articles: 500 years of coppice-with-standards management in Meerdaal Forest (Central Belgium)

2016-03-17

Vandekerkhove K, Baeté H, Van Der Aa B, De Keersmaeker L, Thomaes A, Leyman A, Verheyen K

500 YEARS OF COPPICE-WITH-STANDARDS MANAGEMENT IN MEERDAAL FOREST (CENTRAL BELGIUM)

Abstract: For centuries, coppice and coppice-with-standards were the main forest management systems in the northern and central parts of present Belgium. A high population density and a low forest cover in the whole region resulted in a high demand for wood, therefore strict regulations and management regimes were necessary to prevent overexploitation. We illustrate this with a well-documented case, that of Meerdaal Forest in Central Belgium, with reference to other sites in the region. Meerdaal Forest is a woodland 30 km east of Brussels. For centuries its high quality timber stands, especially oak, were managed as coppice-with-standards, with a gradually increasing share of standard trees. Using archive documents and ancient maps, we have reconstructed how this coppice-with-standard management has been developed and optimized over a period of about 500 years. Changes in cutting cycles and configurations were discerned, with a gradual increase of the importance of the standard layer over time. The analysis also showed how wood production could be successfully combined with other sources of income like grazing and pannage. We conclude that former managers of Meerdaal Forest, notwithstanding their lack of scholarship and reference works, developed a state-of-the-art sustainable and flexible management regime that allowed to provide high revenues during many centuries.

Keywords: Coppice-with-standards, Archive Documents, Ancient Maps, Long-term Forest Changes, Grazing, Pannage

iForest 9 (4): 509-517 (2016) - doi: 10.3832/ifor1782-008
https://iforest.sisef.org/contents/?id=ifor1782-008

Research Articles: Small forest parcels, management diversity and valuable coppice habitats: an 18th century political compromise in the Osnabrück region (NW Germany) and its long-lasting legacy

Mölder A — 2016-03-17

Mölder A

SMALL FOREST PARCELS, MANAGEMENT DIVERSITY AND VALUABLE COPPICE HABITATS: AN 18TH CENTURY POLITICAL COMPROMISE IN THE OSNABRüCK REGION (NW GERMANY) AND ITS LONG-LASTING LEGACY

Abstract: This study underlines the often under-estimated importance of forest ownership and land tenure in European forest biodiversity studies which are crucial for the management, structure, and tree species composition of woodland. In particular it is assumed that, in regions with both state-owned forests and smaller private forests, the latter contain more relict habitats shaped by historical woodland management practices. A government decree of 1721, a political compromise, was crucial to the present-day woodland ownership pattern and distribution of woodland habitats in the Osnabrück region (northwest Germany). It resulted in the privatization of woodlands held in common for centuries and created a huge number of small, private forest parcels in the 18th century. These developments are discussed in relation to Europe-wide processes in forest affairs. Mainly due to the low economic importance of these forest parcels, as well as the individualism of the forest owners, coppice structures providing valuable habitats have persisted until today. For instance, over-aged coppice stands provide important habitat conditions for saproxylic species and unique herbaceous layers. These valuable habitats must be protected while creating new coppice stands to eventually take their place in future decades. Management plans for Natura 2000 sites in the Osnabrück region should address this problem while reconciling any conflict of interests between private owners and nature conservation organizations. Researchers are encouraged to give more consideration to the important relationship between current woodland biodiversity and the history of forest ownership patterns.

Keywords: Biodiversity Conservation, Forest History, Forest Ownership, Forest Policy, Historical Ecology, Land Tenure, Nature Conservation, Silviculture

iForest 9 (4): 518-528 (2016) - doi: 10.3832/ifor1834-009
https://iforest.sisef.org/contents/?id=ifor1834-009

Research Articles: Oak sprouts grow better than seedlings under drought stress

Pietras J, Stojanović M, Knott R, Pokorný R — 2016-03-17

Pietras J, Stojanović M, Knott R, Pokorný R

OAK SPROUTS GROW BETTER THAN SEEDLINGS UNDER DROUGHT STRESS

Abstract: This study focused on the comparison of two contrasting forest regeneration types and their susceptibility to drought stress. Transpiration and biomass production were studied on young sessile oak trees Quercus petraea (Matt.) Liebl. regenerated as sprouts and seedlings, and grown in a coppice experimental site in the Czech Republic. Biomass production was estimated using destructive methods, while transpiration was derived from sap flow measurements and assessed according to the plant biometry and microclimatic conditions. Sprouts were characterized by a significantly higher diameter, height, leaf area and above-ground biomass and by a lower wood density as compared with seedlings of the same age. Moreover, the sap flow of sprouts was higher than that of seedlings, which was explained by the plant dimension. Transpiration, expressed as sap flow scaled to plant leaf area, did not differ between seedlings and sprouts when soil water was not limiting. However, during drought periods, when soil water potential dropped below -1.4 MPa, sprouts transpired significantly more than seedlings. Our results confirm that sprouts have access to a larger water pool via the old stump root system and are able to draw more water under drought. Moreover, sprouts seemed to be less susceptible to water limitations than seedlings of similar age. Less influence of drought on sprouts may partially explain their higher above-ground biomass production. Based on our results, coppice could be an appropriate management system to be adopted in sites characterized by frequent or extreme drought periods.

Keywords: Drought Stress, Sap Flow, Transpiration, Biomass Production, Sessile Oak, Coppice, Sprout, Seedling

iForest 9 (4): 529-535 (2016) - doi: 10.3832/ifor1823-009
https://iforest.sisef.org/contents/?id=ifor1823-009

Review Papers: Post-fire soil hydrology, water erosion and restoration strategies in Andosols: a review of evidence from the Canary Islands (Spain)

Neris J, Santamarta JC, Doerr SH, Prieto F, Agulló-Pérez J, García-Villegas P — 2016-03-17

Neris J, Santamarta JC, Doerr SH, Prieto F, Agulló-Pérez J, García-Villegas P

POST-FIRE SOIL HYDROLOGY, WATER EROSION AND RESTORATION STRATEGIES IN ANDOSOLS: A REVIEW OF EVIDENCE FROM THE CANARY ISLANDS (SPAIN)

Abstract: Andosols are the most characteristic soils of volcanic regions such as the forested, fire-prone, hillslopes of the mountainous Canary Islands (Spain). Due to their volcanic nature, these soils have traditionally been considered highly resistant to water erosion processes in undisturbed conditions, but are also highly susceptible to environmental disturbances. In addition, volcanic terrains often underlie heavily-populated, steep areas where torrential rains are frequent, increasing the threat to the population and infrastructures down-slope. Numerous hydrological and erosional catastrophic events in disturbed Andosols in the Canary Islands and worldwide, leading to major losses to lives and properties, have been historically and recently reported. The impact of environmental alterations such as land use change on hydrological and erosional response of Andosols has been widely studied in the Canary Islands and worldwide. However, the effect on this soil type of wildfires, generally considered one of the main geomorphological agents, and historically connected to the forested fire-prone Andosols of the islands, has had scant attention to date. This review seeks to redress this knowledge gap by: (i) evaluating the factors affecting the susceptibility of Andosols to catastrophic hydrological and erosional events; (ii) summarizing the published studies on the impact of fire and the post-fire response of this soil type and the specific restoration measures developed to date; and (iii) identifying research gaps and suggesting new lines of investigation in order to reduce the hydrological and erosional risks in these particular terrains.

Keywords: Volcanic Ash Soils, Wildfires, Catastrophic Events, Disaster Risk Reduction, Erosion Mitigation, Post-fire Restoration

iForest 9 (4): 583-592 (2016) - doi: 10.3832/ifor1605-008
https://iforest.sisef.org/contents/?id=ifor1605-008

Research Articles: Outcome of Ceratocystis platani inoculations in Platanus × acerifolia in relation to season and inoculum dose

Pilotti M, Di Lernia G, Modesti V, Lumia V, Brunetti A — 2016-03-17

Pilotti M, Di Lernia G, Modesti V, Lumia V, Brunetti A

OUTCOME OF CERATOCYSTIS PLATANI INOCULATIONS IN PLATANUS × ACERIFOLIA IN RELATION TO SEASON AND INOCULUM DOSE

Abstract: Ceratocystis platani is the causal agent of canker stain, the most destructive disease of Platanus spp. The selection of resistant tree genotypes should be an effective method of controlling the disease. Although breeding programs for resistance have been developed, there is no validated protocol for an in depth evaluation of the resistance phenotype. Testing the variables to identify the conditions that fully challenge the genetic potential of the host is crucial not to overestimate labile resistant phenotypes. Here we report results of testing different inoculum doses and inoculation times - early and late spring, summer and autumn - on the response of susceptible plane genotypes. Late spring inoculation gave rise to the quickest death pattern occurred, followed by early spring inoculation. Nevertheless Ceratocystis platani was aggressive also in the hottest period of the summer. The capacity of C. platani to initiate canker stain in the hottest period of the year underlines its capacity to be virulent in a wide range of temperatures. Although autumnal inoculation enabled fungus entry, its progression was precociously halted as effective and stable resistance reactions were opposed by the majority of the trees. An in vitro study of mycelial growth and conidial germination confirmed the capacity of the fungus to be active or to keep the viability in a wide range of temperatures such as in the three seasons that were taken into consideration. Thus we hypothesize that the failure of symptom expression after autumnal inoculation might be due to a combination of a temperature-linked reduction in pathogen virulence, and a season-linked resistant reaction of the host. Overall our data suggest that, in the context of legal sanitary measures, only the coldest and driest periods of the year should be considered for pruning and the removal of infected trees. The different inoculum doses did not condition the death pattern. Comparing germination in suspensions at 1.000 and 10.000 conidia per µl, self-inhibition germination occurred, as the germination rate was inversely correlated with the conidia concentration. This is a first step in the definition of a resistance-testing protocol for an in depth evaluation of resistance to canker stain.

Keywords: Inoculum Dose, Inoculation Time, Resistance Reaction, Self-inhibition Conidia Germination, Thermal Niche, Resistance Testing Protocol

iForest 9 (4): 608-617 (2016) - doi: 10.3832/ifor1594-008
https://iforest.sisef.org/contents/?id=ifor1594-008

Research Articles: Effect of topography on tree species composition and volume of coarse woody debris in an Oriental beech (Fagus orientalis Lipsky) old growth forests, northern Iran

Sefidi K, Esfandiary Darabad F, Azaryan M — 2016-03-17

Sefidi K, Esfandiary Darabad F, Azaryan M

EFFECT OF TOPOGRAPHY ON TREE SPECIES COMPOSITION AND VOLUME OF COARSE WOODY DEBRIS IN AN ORIENTAL BEECH (FAGUS ORIENTALIS LIPSKY) OLD GROWTH FORESTS, NORTHERN IRAN

Abstract: There is an emerging interest in the relationships between forest structure and topographic aspects. Still, such patterns have been scarcely studied in undisturbed mixed beech forests in northern Iran. We investigated the influence of topographical factors including aspect, slope degree, and landform index (LI) on the distribution of dominant tree species and coarse woody debris (CWD). Tree density and basal area were not significantly correlated with any of the measured parameters, except a moderate relation between basal area and LI (r = - 0.376; P = 0.029). Redundancy analysis (RDA) of the tree layer revealed a significant relationship between the measured environmental variables and species distributions. CWD volume showed significant negative correlation with percent canopy coverage and was highly correlated with slope. Density of CWD in decay class IV was significantly correlated with aspect and percent of canopy cover. Analyses of CWD distributions in relation to both living vegetation and topographic gradients showed a highly complex interplay of factors driving the distribution of CWD across the forest stands.

Keywords: Stand Structure, Physical Geography, Landform, Caspian Forest, Fagus orientalis

iForest 9 (4): 658-665 (2016) - doi: 10.3832/ifor1080-008
https://iforest.sisef.org/contents/?id=ifor1080-008

Research Articles: Density and spatial distribution of beech (Fagus sylvatica L.) regeneration in Norway spruce (Picea abies (L.) Karsten) stands in the central part of the Czech Republic

Dobrovolny L — 2016-03-12

Dobrovolny L

DENSITY AND SPATIAL DISTRIBUTION OF BEECH (FAGUS SYLVATICA L.) REGENERATION IN NORWAY SPRUCE (PICEA ABIES (L.) KARSTEN) STANDS IN THE CENTRAL PART OF THE CZECH REPUBLIC

Abstract: The conversion of Norway spruce monocultures to mixed forest is a long-term and costly process, and little information is available on the silvicultural use of spontaneous regeneration of native tree species to such purposes. In this context, we focused on the natural expansion of European beech in pure Norway spruce stands currently occurring in central Europe. The study was conducted in three secondary spruce stands with single adult (seed) beech trees growing on acidic sites of the fir-beech vegetation zone in the Bohemian-Moravian Highlands (Czech Republic). The regeneration strategy of beech and spruce (in terms of density and height increment) was studied under different light regimes (expressed using the indirect site factor - ISF) on the forest edge (9.7-41.2% ISF) and within gaps in the forest interior (10.7-20.8% ISF). Beech showed a broad light adaptability, being present under the spruce canopy with high density, depending on the distance from beech seed trees. Sparse beech saplings were found at a distance of more than 100 m from adult beech trees; however, abundant beech regeneration was found up to a distance of 25 m. Contrastingly, the density and growth in height of the spruce regeneration was strongly affected by light conditions. Spruce reached a density higher than beech in the understory where ISF > 17% (i.e., up to a distance of 45 m from the stand edge or within gaps no smaller than 400 m2), and competed with beech in terms of height growth where ISF > 20% (i.e., at the very stand edges). Knowledge of the spatial pattern and the light strategy of both species provided useful information to support the conversion of spruce monocultural stands to mixed spruce-beech forests.

Keywords: Natural Regeneration, Beech, Spruce Monoculture, Competition, Conversion, Mixed Forest

iForest 9 (4): 666-672 (2016) - doi: 10.3832/ifor1581-008
https://iforest.sisef.org/contents/?id=ifor1581-008

Research Articles: Effects of traditional coppice practices and microsite conditions on tree health in a European beech forest at its southernmost range

Cullotta S, La Placa G, Maetzke FG — 2016-03-12

Cullotta S, La Placa G, Maetzke FG

EFFECTS OF TRADITIONAL COPPICE PRACTICES AND MICROSITE CONDITIONS ON TREE HEALTH IN A EUROPEAN BEECH FOREST AT ITS SOUTHERNMOST RANGE

Abstract: European beech (Fagus sylvatica) grows at the southern limit of its range in the mountain-Mediterranean vegetation belt up to the timberline. The southernmost beech forests of Sicily (southern Italy) show peculiar ecological, structural and silvicultural characteristics, growing in fragmented and isolated stands near the timberline and in topographically marginal unfavorable habitats. Past silvicultural practices increased the heterogeneity of stand structure at these sites. We compared stand structural characteristics and tree health in coppice-cut and control beech stands with respect to the local topographic gradient (bottom, slope and ridge) and canopy cover (clearing/border vs. interior trees). Our results clearly showed a correlation between declining tree health (crown and bark damage, higher percentage of dead trees and lower seedling density) and recent coppice-cuts, poor (marginal) site quality (on ridges and slopes) and reduced canopy cover (in clearing/border trees). The decrease of tree health indicate an increasing threat to the long-term viability of beech stands facing multiple environmental stress factors (such as those related to southern latitude and topographic position). Declining tree health in the control plots also supports this hypothesis. We concluded that traditional forest management practices, such as coppice-cuts applied regardless to the specific microenvironmental conditions, may pose a risk to beech forest health at the southernmost edge of the species’ range.

Keywords: Marginal Beech Sites, Site-specific Ecology, Topographic Gradient, Cover Fragmentation, Silviculture, Coppice-cuts, Tree Damage, Madonie Mts, Sicily

iForest 9 (4): 673-681 (2016) - doi: 10.3832/ifor1603-008
https://iforest.sisef.org/contents/?id=ifor1603-008

Research Articles: Impact of thinning on carbon storage of dead organic matter across larch and oak stands in South Korea

Kim S, Han SH, Lee J, Kim C, Lee ST, Son Y — 2016-03-01

Kim S, Han SH, Lee J, Kim C, Lee ST, Son Y

IMPACT OF THINNING ON CARBON STORAGE OF DEAD ORGANIC MATTER ACROSS LARCH AND OAK STANDS IN SOUTH KOREA

Abstract: Dead organic matter is important in carbon (C) sequestration because it accounts for a significant proportion of forest C storage. As thinning could alter the C storage of dead organic matter, this study aimed to assess the effect of thinning on the C storage of dead organic matter including the forest floor, mineral soil at a depth of 0-30 cm, and coarse woody debris in larch and oak forests in South Korea. Differing intensities of thinning were applied to four larch and four oak stands, and the C storage of dead organic matter in thinned and control plots was compared three years after thinning. The effect sizes were estimated based on Hedges’ d to measure the influence of thinning. Total C storage of dead organic matter tended to be higher in the thinned plots (larch: 82.45 Mg C ha-1 and oak: 82.56 Mg C ha-1) than in the control plots (larch: 72.07 Mg C ha-1 and oak: 74.79 Mg C ha-1). However, estimation of effect size found that the cumulative effect size was not significant for the C storage of the forest floor, mineral soil, coarse woody debris, and dead organic matter. Only a few of the individual treatments exhibited significant effect sizes for mineral soil C storage in two larch stands and coarse woody debris C storage in two oak stands. The results indicated that the applied thinning treatments might have no consistently significant impact on the C storage of dead organic matter in the larch and oak stands after three years, though thinning may have had an idiosyncratic influence on the C storage of dead organic matter in a few of the study stands.

Keywords: Carbon Sequestration, Dead Organic Matter, Effect Size, Forest Thinning

iForest 9 (4): 593-598 (2016) - doi: 10.3832/ifor1776-008
https://iforest.sisef.org/contents/?id=ifor1776-008

Research Articles: Optimizing the management of uneven-aged Pinus nigra stands between two stable positions

López Torres I, Ortuño Pérez S, García Robredo F, Fullana Belda C — 2016-03-01

López Torres I, Ortuño Pérez S, García Robredo F, Fullana Belda C

OPTIMIZING THE MANAGEMENT OF UNEVEN-AGED PINUS NIGRA STANDS BETWEEN TWO STABLE POSITIONS

Abstract: This study proposes a discrete optimal control model to obtain harvest strategies that maximize the net present value (NPV) of the timber harvested from uneven-aged Pinus nigra stands located in the Spanish Iberian System, between two stable positions. The model was constructed using an objective function that integrates financial data on the harvesting operations with a matrix model describing the population dynamics. The initial and final states are given by the stable diameter distribution of the stand, and the planning horizon is 70 years. The scenario analysis corresponding to the optimal solutions revealed that the stand diameter distribution does not deviate substantially from the equilibrium position over time and that the NPV for the optimal harvesting schedule was always greater than the NPV for the “sustainable/stable” harvesting strategy. The NPV increase for the different scenarios is between 5.36% and 14.43%, showing a greater increase in higher site index scenarios and higher recruitments.

Keywords: Sustainability, Stability, Equilibrium, Optimal Harvesting, Discrete Optimal Control, Matrix Model

iForest 9 (4): 599-607 (2016) - doi: 10.3832/ifor1298-008
https://iforest.sisef.org/contents/?id=ifor1298-008

Research Articles: Does degradation from selective logging and illegal activities differently impact forest resources? A case study in Ghana

2016-01-29

Vaglio Laurin G, Hawthorne WD, Chiti T, Di Paola A, Cazzolla Gatti R, Marconi S, Noce S, Grieco E, Pirotti F, Valentini R

DOES DEGRADATION FROM SELECTIVE LOGGING AND ILLEGAL ACTIVITIES DIFFERENTLY IMPACT FOREST RESOURCES? A CASE STUDY IN GHANA

Abstract: Degradation, a reduction of the ecosystem’s capacity to supply goods and services, is widespread in tropical forests and mainly caused by human disturbance. To maintain the full range of forest ecosystem services and support the development of effective conservation policies, we must understand the overall impact of degradation on different forest resources. This research investigates the response to disturbance of forest structure using several indicators: soil carbon content, arboreal richness and biodiversity, functional composition (guild and wood density), and productivity. We drew upon large field and remote sensing datasets from different forest types in Ghana, characterized by varied protection status, to investigate impacts of selective logging, and of illegal land use and resources extraction, which are the main disturbance causes in West Africa. Results indicate that functional composition and the overall number of species are less affected by degradation, while forest structure, soil carbon content and species abundance are seriously impacted, with resources distribution reflecting the protection level of the areas. Remote sensing analysis showed an increase in productivity in the last three decades, with higher resiliency to change in drier forest types, and stronger productivity correlation with solar radiation in the short dry season. The study region is affected by growing anthropogenic pressure on natural resources and by an increased climate variability: possible interactions of disturbance with climate are also discussed, together with the urgency to reduce degradation in order to preserve the full range of ecosystem functions.

Keywords: Tropical Forest, Remote Sensing, Degradation, Logging, Guild, Africa

iForest 9 (3): 354-362 (2016) - doi: 10.3832/ifor1779-008
https://iforest.sisef.org/contents/?id=ifor1779-008

Short Communications: Differential adaptations in nursery seedlings from diverse Chilean provenances of Peumus boldus Mol.

Magni CR, Espinoza SE, Garrido EF, Santelices RE, Cabrera AM — 2016-01-29

Magni CR, Espinoza SE, Garrido EF, Santelices RE, Cabrera AM

DIFFERENTIAL ADAPTATIONS IN NURSERY SEEDLINGS FROM DIVERSE CHILEAN PROVENANCES OF PEUMUS BOLDUS MOL.

Abstract: Seed germination, seedling growth and biomass allocation of the endemic species Peumus boldus Mol. (Boldo) were studied in four provenances (two northern and two southern provenances) from central Chile. Seeds collected from five different mother plants for each provenance were sowed in plastic pots and placed in an ambient nursery. Germinated seeds were transplanted to 130-mL containers and cultivated under nursery conditions during one growing season. Germination capacity, seed weight, morphological traits of seedlings (root collar diameter, height, number of leaves, foliar area, root length), their biomass allocation pattern (dry mass of leaves, shoots and roots) and survival were analyzed. Results showed significant differences among provenances and mother plants for most traits. Northern provenances showed slower germination, smaller size, higher root biomass, lesser leaf area, and higher survival, while seedlings from southern provenances were taller, with more body mass, larger leaf area and lower root biomass. We concluded that northern provenances of Peamus boldus are more tolerant to drought and therefore are suitable for ecological restoration of drought-prone Mediterranean sites, while the use of southern provenances must be restricted to restoration of more humid environments.

Keywords: Boldo, Habitat Differentiation, Adaptation, Seed Provenances, Seedling Growth, Survival

iForest 9 (3): 409-413 (2016) - doi: 10.3832/ifor1893-008
https://iforest.sisef.org/contents/?id=ifor1893-008

Research Articles: Spatial diversity of forest regeneration after catastrophic wind in northeastern Poland

Szmyt J, Dobrowolska D — 2016-01-29

Szmyt J, Dobrowolska D

SPATIAL DIVERSITY OF FOREST REGENERATION AFTER CATASTROPHIC WIND IN NORTHEASTERN POLAND

Abstract: We examined the spatial diversity of young growth established after the catastrophic windthrow occurred in 2002 in the northeastern part of Poland. Our observations and measurements were conducted on permanent circular measurement plots located in the Szast Protected Forest (continental lowland temperate forests) that were established 3 years after the windstorm and left to natural succession. We evaluated the spatial indices characterizing the four main aspects of stand structure: the spatial arrangement of seedlings and saplings, species mingling, tree size diversity at the local spatial scale and the overall structural complexity index. The calculations were conducted in parts of the forest with differing severity of disturbance. The obtained results indicated the prevalence of a random arrangement of young growth. Clumps of regeneration were observed to a lesser degree in all parts of the forest. The species diversity was moderate and was the highest in the slightly or severely disturbed stands. Scots pine formed homogenous groups of regeneration and oaks were intermingled among other tree species. The height of the natural regeneration was moderately or highly differentiated in all stands. The overall structural diversity index showed that stand regeneration in the slightly or moderately disturbed stands was more differentiated than the young growth in the severely disturbed stands. The size differentiation of young growth is a long-lasting process and thus should be considered in practices aimed at the re-growing of areas after a natural disturbance. This process might be used to the replace monocultures with more diversified forests even in poor forest site types.

Keywords: Spatial Diversity, Spatial Indices, Natural Regeneration, Windthrow, Forest Succession

iForest 9 (3): 414-421 (2016) - doi: 10.3832/ifor1699-008
https://iforest.sisef.org/contents/?id=ifor1699-008

Research Articles: Contribution of environmental variability and ecosystem functional changes to interannual variability of carbon and water fluxes in a subtropical coniferous plantation

Tang Y, Wen X, Sun X, Chen Y, Wang H — 2016-01-25

Tang Y, Wen X, Sun X, Chen Y, Wang H

CONTRIBUTION OF ENVIRONMENTAL VARIABILITY AND ECOSYSTEM FUNCTIONAL CHANGES TO INTERANNUAL VARIABILITY OF CARBON AND WATER FLUXES IN A SUBTROPICAL CONIFEROUS PLANTATION

Abstract: Accurate quantification of the contribution of environmental variability and functional changes to the interannual variability of net ecosystem production (NEP) and evapotranspiration (ET) in coniferous forests is needed to understand global carbon and water cycling. This study quantified these contributions to the interannual variability of NEP and ET for a subtropical coniferous plantation in southeastern China, and the effect of drought stress on these contributions was also investigated. NEP and ET were derived from eddy covariance measurements carried out over the period 2003-2012. A homogeneity-of-slopes model was adopted to quantify the contribution to the interannual variability of these fluxes. Environmental variability accounted for 71% and 85.7% of the interannual variability of NEP and ET, respectively; however, functional changes accounted for only 11.3% and 5.9%, respectively. Furthermore, functional changes explained more of the interannual variability of NEP in dry years (16.3%) than in wet years (3.8%), but there was no obvious change in the contribution of functional changes to the interannual variability of ET in dry (4.7%) or wet (5.5%) years. Thus, environmental variability rather than ecosystem functional changes dominated the interannual variability of both ET and NEP. However, different environmental variables controlled the interannual variability of NEP and ET. The results also indicated that, compared with NEP, ET was more resistant to drought stress through the self-regulating mechanisms of this plantation.

Keywords: Environmental Variability, Functional Changes, Net Ecosystem Production (NEP), Evapotranspiration (ET), Subtropical Plantation

iForest 9 (3): 452-460 (2016) - doi: 10.3832/ifor1691-008
https://iforest.sisef.org/contents/?id=ifor1691-008

Research Articles: Investigating the effect of selective logging on tree biodiversity and structure of the tropical forests of Papua New Guinea

Testolin R, Saulei S, Farcomeni A, Grussu G, Yosi C, De Sanctis M, Attorre F — 2016-01-25

Testolin R, Saulei S, Farcomeni A, Grussu G, Yosi C, De Sanctis M, Attorre F

INVESTIGATING THE EFFECT OF SELECTIVE LOGGING ON TREE BIODIVERSITY AND STRUCTURE OF THE TROPICAL FORESTS OF PAPUA NEW GUINEA

Abstract: Unsustainable exploitation of tropical forest resources is raising worldwide concern. In Papua New Guinea (PNG) timber harvesting has been identified as a major contributor to deforestation and forest degradation but its impact on biodiversity is still poorly understood. In this study we investigated the effect of selective logging on tree taxonomic composition, structure and diversity of PNG forests. We used data from 101 one-hectare permanent sample plots (PSPs) belonging to two vegetation types: low altitude forests on plains and fans (type P) and low altitude forests on uplands (type H). We used multivariate techniques to test for significant differences in species composition between plots of different vegetation types and disturbance regimes, identifying the tree taxa to which these differences could be ascribed. ANOVA was used to test for differences between logged-over and unlogged forest PSPs with respect to biodiversity (richness, Shannon’s diversity, Pielou’s evenness) and stand structure (stem density, basal area - BA). Temporal trends of forest features were analyzed using linear regression. Significant differences in taxonomic composition were found between logged-over and unlogged plots of the H type (p = 0.04). No differences were found in richness, diversity and evenness between logged-over and unlogged forest plots, while stem density was higher in the latter (421 ± 153 stems ha-1). Greater BA was found in unlogged forests (30.28 ± 4.45 m2 ha-1) of the H type when compared to the logged-over stands (15.52 ± 4.04 m2 ha-1). We detected positive trends in richness (0.55 ± 0.19 taxa ha-1 yr-1) and diversity after logging. Furthermore, H type forest exhibited positive trends in stem density (9 ± 1 stems ha-1 yr-1) and BA (0.42 ± 0.06 m2 ha-1 yr-1) with elapsed time since harvesting. Our analysis highlights some significant effects of logging activities on biodiversity and structure of PNG forests. Additionally, forests exhibited a significant recovery with respect to richness, diversity and stand structure. These preliminary results will be compared with data collected by the forthcoming National Forest Inventory in order to assess and monitor the effects of human activities and ecological factors on PNG forest biodiversity and develop appropriate conservation measures and sustainable management strategies.

Keywords: Selective Logging, Biodiversity, Basal Area, Papua New Guinea, Multivariate Analysis, National Forest Inventory, Permanent Sample Plots, REDD+

iForest 9 (3): 475-482 (2016) - doi: 10.3832/ifor1732-008
https://iforest.sisef.org/contents/?id=ifor1732-008

Research Articles: Spatial distribution pattern of Mezilaurus itauba (Meins.) Taub. Ex mez. in a seasonal forest area of the southern Amazon, Brazil

Ebert A, Brito Da Costa R, Brondani GE — 2016-01-25

Ebert A, Brito Da Costa R, Brondani GE

SPATIAL DISTRIBUTION PATTERN OF MEZILAURUS ITAUBA (MEINS.) TAUB. EX MEZ. IN A SEASONAL FOREST AREA OF THE SOUTHERN AMAZON, BRAZIL

Abstract: Spatial analysis of forest tree distribution is a powerful tool to respond to basic ecological questions, and represent a useful support to strategies of genetic conservation and sustainable management practices of forest resources. Spatial analysis techniques combined with the use of Geographical Information Systems have been commonly applied to the study of stochastic processes in order to determine the existence of clusters to be related to microenviromental conditions and/or genetic factors. The present study focused on the distribution patterns of individuals of Mezilaurus itauba in a seasonal forest of the southern Amazon, with the aim of providing information about the spatial arrangement of these species at the juvenile and adult stages. Ripley’s K function with radius of 10, 20 and 30 m was used to describe spatial distribution patterns. The hypothesis of complete spatial randomness (CSR) of individuals was tested by constructing confidence envelopes for the Ripley’s K function through Monte Carlo simulations using a Poisson homogeneous process. The results obtained suggest a general random distribution of individuals, though a tendency to clustering at close distances was detected for individuals classified as adults (DBH > 50 cm). Contrastingly, a completely randomized spatial pattern was found for juveniles trees (DBH < 50 cm). Our results provide a useful baseline for the development of sustainable management plans and conservation of Mezilaurus itauba, as well as for other economically-exploited, native tree species in the southern Amazon forest.

Keywords: Ripley’s K Function, Spatial Distribution Patterns, Forest Management, Conservation of Biodiversity, Horizontal Structure

iForest 9 (3): 497-502 (2016) - doi: 10.3832/ifor1427-008
https://iforest.sisef.org/contents/?id=ifor1427-008

Research Articles: Nine-year monitoring of cambial seasonality and cell production in Norway spruce

Giagli K, Gričar J, Vavrčík H, Gryc V — 2016-01-16

Giagli K, Gričar J, Vavrčík H, Gryc V

NINE-YEAR MONITORING OF CAMBIAL SEASONALITY AND CELL PRODUCTION IN NORWAY SPRUCE

Abstract: We analyzed the relationship between weather conditions and year-to-year (1981-1989) variation in the seasonal dynamics of cambial cell production (CCP) in Norway spruce in a monoculture forest area in the Czech Republic. We found that the timing of CCP greatly varied among the studied years. The onset of CCP occurred at the beginning of May and was strongly correlated with the April mean temperature. CCP ceased by the end of August. The timing of the cessation of CCP was more variable among trees and among years than its onset. The amount of precipitation positively influenced the duration of CCP and the average rate of cell production positively correlated to the minimum temperature in January-April, as well as the maximum temperature during the growing period. Our results show that the timing and the rate of CCP of xylem cells are influenced by temperature and precipitation. However, weather-xylem growth relations of spruce from temperate forests under climatic conditions are complex, since trees are known to respond less strongly to climatic average variation than influences of extreme conditions.

Keywords: Picea abies, Temperature, Precipitation, Wood Formation, Xylem Increment, Light Microscopy

iForest 9 (3): 375-382 (2016) - doi: 10.3832/ifor1771-008
https://iforest.sisef.org/contents/?id=ifor1771-008

Research Articles: Multifactor empirical mapping of the protective function of forests against landslide occurrence: statistical approaches and a case study

Cimini D, Portoghesi L, Madonna S, Grimaldi S, Corona P — 2016-01-16

Cimini D, Portoghesi L, Madonna S, Grimaldi S, Corona P

MULTIFACTOR EMPIRICAL MAPPING OF THE PROTECTIVE FUNCTION OF FORESTS AGAINST LANDSLIDE OCCURRENCE: STATISTICAL APPROACHES AND A CASE STUDY

Abstract: Forests are increasingly valued for services beyond timber and non-timber products including land protection with respect to events such as landslides, soil erosion, floods and avalanches. The most important properties of a protective forest are its ecological and mechanical stability. Planning and implementing multifunctional forest management in protective forests is challenging because of the trade-offs and synergies among the many functions of the forest. In this study, a multifactor empirical method is presented for assessing the protective role of forests on a stand scale with respect to landslide occurrence. Multifactor methodologies typically estimate landslide susceptibility exploiting the relationship between past landslide patterns and site characteristics. Two statistical approaches were here applied to assess the probability of landslide occurrence: the weight-of-evidence technique and the logistic regression technique. Statistical analysis was performed on the basis of landslide detachment zone only. The question of how to estimate protective forest function was answered through the comparison of models established with different sets of predicting factors. This study ultimately aims to provide a decision-support tool focused on mapping the potential role of forests in landslide-prone areas. A case study from the Italian Alps was considered. The density of landslide detachment outside forest areas proves to be more than twice than that within forest areas.

Keywords: Forest Protective Function, Landslide Susceptibility, Logistic Regression, Weight of Evidence, GIS, Alps

iForest 9 (3): 383-393 (2016) - doi: 10.3832/ifor1740-008
https://iforest.sisef.org/contents/?id=ifor1740-008

Research Articles: Relationship between environmental parameters and Pinus sylvestris L. site index in forest plantations in northern Spain acidic plateau

Bueis T, Bravo F, Pando V, Turrión MB — 2016-01-16

Bueis T, Bravo F, Pando V, Turrión MB

RELATIONSHIP BETWEEN ENVIRONMENTAL PARAMETERS AND PINUS SYLVESTRIS L. SITE INDEX IN FOREST PLANTATIONS IN NORTHERN SPAIN ACIDIC PLATEAU

Abstract: The assessment of forest productivity at early stages of stand development may help to define the most appropriate silviculture treatment to be applied for each stand. Site index (dominant height at a reference age) is a useful tool for forest productivity estimation. The aim of this study was to develop a model to predict site index for Scots pine (Pinus sylvestris L.) plantations in northern Spain acidic plateau by using soil (physical, chemical and biochemical), climatic and physiographic parameters. To meet this objective, data from 35 stands classified into three different site quality classes and 63 soil, climatic and physiographic parameters were examined in order to develop a discriminant model. After selecting 12 discriminant models which were biologically consistent and presented the higher cross-validated rate of correct classification, a model including four parameters (latitude, inorganic Al, porosity and microbial biomass carbon) as predictors was chosen. The discriminant model classified 71% of cases correctly and no inferior-quality stands were misassigned to the highest quality class. Soil and physiographic parameters included in the above model are easily obtainable in the field or by simple laboratory analysis, thus our results can be easily integrated in operational forestry to determine site quality.

Keywords: Soil-Site Method, Site Productivity, Environmental Factor, Discriminant Analysis, Principal Components

iForest 9 (3): 394-401 (2016) - doi: 10.3832/ifor1600-008
https://iforest.sisef.org/contents/?id=ifor1600-008

Research Articles: Tree growth, wood and bark water content of 28 Amazonian tree species in response to variations in rainfall and wood density

Dias DP, Marenco RA — 2016-01-16

Dias DP, Marenco RA

TREE GROWTH, WOOD AND BARK WATER CONTENT OF 28 AMAZONIAN TREE SPECIES IN RESPONSE TO VARIATIONS IN RAINFALL AND WOOD DENSITY

Abstract: Pole diameter and wood density are variables commonly used in allometric equations to estimate tree biomass and carbon stocks in tropical forests. The effect of variations in tree water content on pole diameters is often disregarded in allometric equations. This study aimed to determine the effect of rainfall seasonality on tree growth, stem wood and bark water content and to assess the relationship between water content and wood density (dry mass to fresh mass volume ratio) in 120 trees from 28 species in a terra-firme rain forest in the central Amazon. In 2006, stem wood and bark water content were gravimetrically determined in the dry season (August-September) and rainy season (April-May). In the same year, growth in diameter was measured at monthly intervals in the 120 trees (DBH ≥ 10 cm) with dendrometric bands previously adapted to the tree. Mean wood water content was lower in the dry season than the rainy season. On the contrary, bark water content was higher in the dry season than in the rainy season. Wood densities higher than 0.75 g cm-3 were found in 64.3% of the trees. Trees with denser woods grew slower and had lower stem water content. Monthly rainfall did not affect tree growth in diameter, which was contrary to our initial expectation on the effect of rainfall seasonality on tree growth in central Amazonia. This finding supports the hypothesis that in central Amazonia, the mild dry season is not long enough to deplete soil water beyond the reach of the root system, which allows the trees to grow at quite constant rates over the year.

Keywords: Amazonia, Allometry Equations, Pole Diameter, Rainfall Seasonality

iForest 9 (3): 445-451 (2016) - doi: 10.3832/ifor1676-008
https://iforest.sisef.org/contents/?id=ifor1676-008

Research Articles: Effect of family, crown position, number of winter buds, fresh weight and the length of needle on rooting ability of Pinus thunbergii Parl. cuttings

Hakamata T, Hiraoka Y, Yamamoto S, Kato K — 2016-01-11

Hakamata T, Hiraoka Y, Yamamoto S, Kato K

EFFECT OF FAMILY, CROWN POSITION, NUMBER OF WINTER BUDS, FRESH WEIGHT AND THE LENGTH OF NEEDLE ON ROOTING ABILITY OF PINUS THUNBERGII PARL. CUTTINGS

Abstract: As a measure for contrasting pine wilt disease, which caused serious damage in Japanese black pine (Pinus thunbergii Parl.) by the pine wood nematode (Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle), resistant trees have been widely planted in Japan. The propagation of resistant trees using cuttings obtained from healthy stock plants and inoculated with pine wood nematode is expected to further increase in the next future. To improve the cutting propagation of Japanese black pine trees resistant to pine wilt disease, the factors associated with rooting and root volume were investigated. The type of cutting and the crown position of stock plants from which cuttings were taken, were markedly associated with rooting. The crown position did not show significant interactions with any other investigated factor, while fresh weight of cuttings and their number of winter buds did not affect rooting. The rooting percentage was markedly higher for cuttings taken from the lower crown than for those from the upper crown, as already reported for other coniferous tree species. The length of the longest needle was significantly correlated with the root volume of cuttings, and showed significantly interactions with crown position and fresh weight of cuttings. Such correlation suggests that the growth of needles can be considered a useful predictor in the assessment of the root volume of cuttings during the propagation period, allowing growers to transplant rooted cuttings at the appropriate time without excavating or uprooting. These findings may contribute to the improvement of cutting propagation of Japanese black pine.

Keywords: Cutting Propagation, Crown Position, Rooting, Root Volume, Pinus thunbergii Parl.

iForest 9 (3): 370-374 (2016) - doi: 10.3832/ifor1661-008
https://iforest.sisef.org/contents/?id=ifor1661-008

Research Articles: Assessment of age bias in site index equations

Socha J, Coops NC, Ochal W — 2016-01-11

Socha J, Coops NC, Ochal W

ASSESSMENT OF AGE BIAS IN SITE INDEX EQUATIONS

Abstract: The most widely accepted method of evaluating site productivity is site index. In spite of some important restrictions it is still a useful concept in both forest research and management. One of the most important challenges when using site index is an age trend manifested by a negative correlation between site index and stand age. Age trend may result from the inappropriateness of site index models. In this paper we develop a new approach for assessing age bias in site index models. Field data collected from 311 sample plots established in Norway spruce stands in the Polish region of the Carpathians formed the basis of this study. In the proposed approach the appropriateness of site index models is assessed by analyzing the existence of age trends in residuals of geocentric site index prediction models. Using the developed approach we demonstrated that when significant correlations exist between residuals of site index prediction models and stand age, it likely indicates the existence of an age trend and thus the inappropriateness of site index model. To remedy this situation, we demonstrated that the observed age trend can be quantified and utilized in new, non-biased, site index models.

Keywords: Site Productivity, Age Trend, Climate Change, Height Growth, Site Index Model

iForest 9 (3): 402-408 (2016) - doi: 10.3832/ifor1548-008
https://iforest.sisef.org/contents/?id=ifor1548-008

Research Articles: Estimates of selective logging impacts in tropical forest canopy cover using RapidEye imagery and field data

Pinagé ER, Matricardi EAT, Leal FA, Pedlowski MA — 2016-01-11

Pinagé ER, Matricardi EAT, Leal FA, Pedlowski MA

ESTIMATES OF SELECTIVE LOGGING IMPACTS IN TROPICAL FOREST CANOPY COVER USING RAPIDEYE IMAGERY AND FIELD DATA

Abstract: Selective logging is one of the leading causes of forest degradation in the Brazilian Amazon region. The Brazilian Federal government has adopted a forest concession policy as a strategy to mitigate impacts of selective logging and regulate operations of the tropical timber industry in Brazil. This study used fractional forest coverage derived from satellite imagery and field data to assess forest degradation in two selectively logged study sites within the Jamari National Forest, a protected area located in the western Brazilian state of Rondônia. Initially, we estimated the fractional coverage from vegetation indices using RapidEye imagery and compared to gap fraction data derived from hemispherical photos acquired in the field. Subsequently, we estimated the impacts of different types of selective logging activities (log decks, primary and secondary roads, tree fall gaps, and skid trails) on forest cover using the fractional coverage dataset. The NDVI showed the highest R2 (0.56), indicating that 56% of the sample variation in fractional coverage derived from ground measurements can be explained by fractional coverage derived from the NDVI model. Our results also showed that the intensity of canopy impacts may vary according to the selective logging activity, ranging from skid trails to log decks which had the lightest and the heaviest canopy impacts, respectively.

Keywords: Timber Harvesting, Hemispherical Photographs, Satellite Imagery, Forest Degradation, Forest Concessions, Brazilian Amazon

iForest 9 (3): 461-468 (2016) - doi: 10.3832/ifor1534-008
https://iforest.sisef.org/contents/?id=ifor1534-008

Research Articles: Influence of salvage logging on forest recovery following intermediate severity canopy disturbances in mixed beech dominated forests of Slovenia

Fidej G, Rozman A, Nagel TA, Dakskobler I, Diaci J — 2016-01-07

Fidej G, Rozman A, Nagel TA, Dakskobler I, Diaci J

INFLUENCE OF SALVAGE LOGGING ON FOREST RECOVERY FOLLOWING INTERMEDIATE SEVERITY CANOPY DISTURBANCES IN MIXED BEECH DOMINATED FORESTS OF SLOVENIA

Abstract: The practice of salvage logging dead and damaged timber following large high severity disturbances has raised much controversy, partly because of the negative ecological effects that such practices have on forest ecosystems. Many of the studies on salvage logging effects, however, have been done on sites damaged by large, severe disturbances. Less is known about the ecological consequences of salvage logging following intermediate severity disturbances that cause partial canopy damage at smaller scales. We examined the response of the herbaceous layer and tree regeneration to salvaged and non-salvaged treatments following small-scale intermediate severity disturbances in eight mixed beech (Fagus sylvatica L.) dominated forest stands in Slovenia. The cover and diversity of herbaceous vegetation, as well as the density and diversity of tree regeneration were similar between treatments across the study sites. The only notable differences between the treatments were that salvaged sites had a larger proportion of shade intolerant tree species in the regeneration layer, while non-salvaged sites tended to have a more well-developed regeneration layer in taller height classes. The results suggest that salvage logging following small-scale intermediate severity disturbances may not hinder forest recovery in mixed beech dominated forests.

Keywords: Fagus sylvatica, Forest Management, Intermediate Severity, Natural Disturbance, Regeneration, Salvage Logging

iForest 9 (3): 430-436 (2016) - doi: 10.3832/ifor1616-008
https://iforest.sisef.org/contents/?id=ifor1616-008

Research Articles: Combined pre-hardening and fall fertilization facilitates N storage and field performance of Pinus tabulaeformis seedlings

Li G, Wang J, Oliet JA, Jacobs DF — 2016-01-07

Li G, Wang J, Oliet JA, Jacobs DF

COMBINED PRE-HARDENING AND FALL FERTILIZATION FACILITATES N STORAGE AND FIELD PERFORMANCE OF PINUS TABULAEFORMIS SEEDLINGS

Abstract: Exponential fertilization during the pre-hardening stage and fall fertilization during the hardening stage have each been used independently to nutrient load seedlings. However, nursery and field responses of seedlings to the combination of exponential fertilization and fall fertilization have received little attention. Chinese pine (Pinus tabulaeformis Car.) container seedlings were exponentially fertilized with accumulated totals of 40, 80 or 120 mg N per seedling during pre-hardening, and fall-fertilized with 0, 12, 24 or 48 mg N per seedling, and were subsequently outplanted and followed for two growing seasons. Interactions of exponential and fall fertilization had significant effects on plant N content in the nursery and first-year height after outplanting. Fall fertilization promoted additional nutrient loading during hardening for the 40-80 mg N per seedling pre-hardening regimes. The highest exponential fertilization rate enhanced N concentration in foliage and roots compared to the other two rates. Maximum diameter was observed in the lowest exponential fertilization rate at the second year after outplanting. Fall fertilization enhanced foliar N concentration. Supplemental 12 and 24 mg N per seedling during fall were more effective in increasing height increment at the second year after outplanting. Our results indicate that pre-hardening fertilization is a useful tool to nutrient load Chinese pine in the nursery and facilitate outplanting performance in the field. In combination, fall fertilization has potential to further augment this response, although further research is needed to precisely match rates of pre-hardening and fall fertilization to optimize seedling performance.

Keywords: Exponential Fertilization, Fall Fertilization, Nutrient-loading, Field Performance, Chinese Pine

iForest 9 (3): 483-489 (2016) - doi: 10.3832/ifor1708-008
https://iforest.sisef.org/contents/?id=ifor1708-008

Research Articles: Agronomic methods for mountain grassland habitat restoration for faunistic purposes in a protected area of the northern Apennines (Italy)

Cervasio F, Argenti G, Genghini M, Ponzetta MP — 2016-01-07

Cervasio F, Argenti G, Genghini M, Ponzetta MP

AGRONOMIC METHODS FOR MOUNTAIN GRASSLAND HABITAT RESTORATION FOR FAUNISTIC PURPOSES IN A PROTECTED AREA OF THE NORTHERN APENNINES (ITALY)

Abstract: The abandonment of pastures often leads to a remarkable deterioration of grasslands, caused by the spread of intrusive, herbaceous and woody species which reduces the general quality of pastures. Different treatments aimed at improving the grassland and enhancing the forage quality of herbaceous resources have been developed to face this problem. We report the results of a five-year experiment conducted in a protected area of central Italy (the “Laghi di Suviana e Brasimone” regional park) on an abandoned pasture inside a beech forest encroached by intrusive species (mainly bracken). We analyzed the effect on sward’s specific composition and grazing value of two agronomic factors: (i) the establishment method (ploughing followed by sowing of a forage mixture versus no intervention), and (ii) the number of cuts performed on vegetation during the growing season (0, 1 or 2 cuts). Plots were arranged according to a split-split-plot experimental design with three replications, with the sampling dates as the main factor, the establishment technique as the subplot factor, and the number of cuts as the sub-subplot factor. In each plot, data were recorded once a month from June to September every year from 2006 to 2010, in order to assess the botanical composition and the quality of the sward. The main pastoral and botanical parameters of pastures were significantly affected by both cutting and sowing. Establishment by sowing significantly reduced the presence of bracken, even with no cuts, with strong effects on the qualitative value of the pasture. A single cut resulted in an efficient recovery of the pasture as compared to cutting twice, especially in sown plots. Our results confirmed that the regular and continued maintenance of the recovered areas is crucial to ensure the long-term preservation of the results achieved by the improvements.

Keywords: Botanical Composition, Grasslands, Grazing Value, Pteridium aquilinum, Sowing

iForest 9 (3): 490-496 (2016) - doi: 10.3832/ifor1515-008
https://iforest.sisef.org/contents/?id=ifor1515-008

Research Articles: Development of monitoring methods for Hemlock Woolly Adelgid induced tree mortality within a Southern Appalachian landscape with inhibited access

2016-01-02

Kantola T, Lyytikäinen-Saarenmaa P, Coulson RN, Holopainen M, Tchakerian MD, Streett DA

DEVELOPMENT OF MONITORING METHODS FOR HEMLOCK WOOLLY ADELGID INDUCED TREE MORTALITY WITHIN A SOUTHERN APPALACHIAN LANDSCAPE WITH INHIBITED ACCESS

Abstract: Hemlock woolly adelgid (Adelges tsugae Annand, HWA) is an introduced invasive forest pest in eastern North America. Herbivory by this insect results in mortality to eastern hemlock (Tsuga canadensis L. Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.). These species occur in landscapes where extreme topographic variation is common. The vegetation communities within these landscapes feature high diversity of tree species, including several other conifer species. Traditional forest inventory procedures and insect pest detection methods within these limited-access landscapes are impractical. However, further information is needed to evaluate the impacts of HWA-induced hemlock mortality. Accordingly, our goal was to develop a semi-automatic method for mapping patches of coniferous tree species that include the living hemlock component and tree mortality by the HWA using aerial images and LiDAR (light detection and ranging) to increase our understanding of the severity and pattern of hemlock decline. The study was conducted in the Linville River Gorge in the Southern Appalachians of western North Carolina, USA. The mapping task included a two-phase approach: decision-tree and support vector machine classifications. We found that about 2% of the forest canopy surface was covered by dead trees and 43% by coniferous tree species. A large portion of the forest canopy surface (over 55%) was covered by deciduous tree species. The resulting maps provide a means for evaluating the impact of HWA herbivory, since this insect was the only significant coniferous mortality agent present within the study site.

Keywords: Decision-tree Classification, Eastern Hemlock, Hemlock Woolly Adelgid, Remote Sensing, Support Vector Machine

iForest 9 (2): 178-186 (2016) - doi: 10.3832/ifor1712-008
https://iforest.sisef.org/contents/?id=ifor1712-008

Research Articles: Usefulness and perceived usefulness of Decision Support Systems (DSSs) in participatory forest planning: the final users’ point of view

Pastorella F, Borges JG, De Meo I — 2016-01-02

Pastorella F, Borges JG, De Meo I

USEFULNESS AND PERCEIVED USEFULNESS OF DECISION SUPPORT SYSTEMS (DSSS) IN PARTICIPATORY FOREST PLANNING: THE FINAL USERS’ POINT OF VIEW

Abstract: In recent decades, the focus of forestry Decision Support Systems (DSSs) has expanded to consider the social dimension of forestry and to support participatory decision-making. A large number of models and tools have become available to solve forest management planning problems. The Usefulness of a DSS depends on the range of tools that it incorporates, and many researches have been developed to evaluate DSSs using Usefulness as parameter. The assessment of Usefulness concerns the effectiveness of a DSS. Furthermore, most assessments take into account the degree of Perceived Usefulness, which is considered an indicator of the impact a system has on job performance. The present study focuses on the analysis of final users’ point of view on the Usefulness and Perceived Usefulness of DSSs in participatory forest planning. The research investigates how forest users’ characteristics and context influence their views on the potentialities of DSSs to enhance both the various phases of the participatory planning process (Usefulness) and job performance (Perceived Usefulness). The study is based on quantitative data collected through two questionnaires e-mailed to a sample of 150 DSSs end users. The questionnaires focused on Usefulness and on Perceived Usefulness topics, respectively. Results indicate that special attention must be given to motivating respondents with a clear explanation of the survey objectives when e-mailing questionnaires. Moreover, results show that, in general, respondents consider DSSs useful at each step of the participatory process, despite differences emerge among steps. The research also shows that respondents’ Perceived Usefulness of DSSs was higher before actually engaging with DSSs. Furthermore, the results highlight differences in Perceived Usefulness to improve job performance, suggesting that the use of DSSs may actually improve job performance more than expected. Specifically, results indicate that improving the technical descriptions of methodologies incorporated in a DSS may contribute to increasing the Perceived Usefulness. The information provided within this research contributes to the advancement of knowledge regarding the Usefulness of DSSs as perceived by forest stakeholders, which in turn supports the improvement of DSS architectures and the development of participatory processes in forest management planning.

Keywords: Forest Management, Decision Support Systems, Participatory Planning, Usefulness, Perceived Usefulness

iForest 9 (3): 422-429 (2016) - doi: 10.3832/ifor1356-008
https://iforest.sisef.org/contents/?id=ifor1356-008

Research Articles: Endangered and endemic species increase forest conservation values of species diversity based on the Shannon-Wiener index

Song Q, Wang B, Wang J, Niu X — 2016-01-02

Song Q, Wang B, Wang J, Niu X

ENDANGERED AND ENDEMIC SPECIES INCREASE FOREST CONSERVATION VALUES OF SPECIES DIVERSITY BASED ON THE SHANNON-WIENER INDEX

Abstract: Species diversity is the most important component of biodiversity and plays an important role in maintaining forest ecosystem processes and stability. The assessment of the forest conservation value of species diversity is commonly carried out based on the Shannon-Wiener index. However, endangered and endemic species were always ignored in previous studies aimed at assessing the conservation value of forest species diversity. In this study, the conservation value of forest species diversity was assessed in two representative provinces of southern and northern China (Yunnan and Jilin provinces, respectively). The conservation values of species diversity for different forest types was calculated based on the standard Shannon-Wiener index, and on two different indexes derived from it by including: (i) an endangered species index (Ei) based on the China Species Red List; (ii) an endemic species index (Bx) based on the geographic distribution of the species considered. The results showed that the inclusion of the endangered and endemic species indexes dramatically increased the forest conservation values in these two provinces. The total conservation value in the Yunnan province was 268.65 billion yuan yr-1 based on the Shannon-Wiener index, 269.78 billion yuan yr-1 after including Ei in the assessment, and 324.44 billion yuan yr-1 after the inclusion of both Ei and Bx. In Jilin province, the total conservation value was 123.94 billion yuan yr-1 based on the standard Shannon-Wiener index, 124.60 billion yuan yr-1 after including Ei, and 125.74 billion yuan yr-1 after including both Ei and Bx in the assessment. Therefore, the inclusion of endangered and endemic species in the assessment of forest conservation values, as well as other aspects related to biodiversity like the presence of ancient trees, can contribute to the protection of endangered and endemic species in these two provinces of China.

Keywords: Species Diversity, Conservation Value, Endangered Species, Endemic Species

iForest 9 (3): 469-474 (2016) - doi: 10.3832/ifor1373-008
https://iforest.sisef.org/contents/?id=ifor1373-008

Research Articles: Distribution of juveniles of tree species along a canopy closure gradient in a tropical cloud forest of the Venezuelan Andes

Quevedo-Rojas A, Jerez-Rico M, Schwarzkopf Kratzer T, García-Núñez C — 2015-12-08

Quevedo-Rojas A, Jerez-Rico M, Schwarzkopf Kratzer T, García-Núñez C

DISTRIBUTION OF JUVENILES OF TREE SPECIES ALONG A CANOPY CLOSURE GRADIENT IN A TROPICAL CLOUD FOREST OF THE VENEZUELAN ANDES

Abstract: Cloud forests represent a minor portion of the world forests, though outstanding in terms of biodiversity, endemisms, and environmental services provided. Understanding the factors that drive the regeneration and species composition of these forests, and in particular how light availability affects the patterns of juvenile tree distribution in the understory, is critical for conservation and restoration programs. In this study, we determined the range-size and overlap of the abundance distribution of juveniles for 20 tree species in an Andean tropical cloud forest in Venezuela along a gradient of percentage canopy openness (%CO) used as a surrogate of light availability. The observed distribution of %CO was then compared with a bounded null model of community structure in order to test light partitioning as a driver of tree species’ coexistence. We measured %CO using hemispherical photography and the abundance and size of juvenile trees in 280 plots of 1-m radius spread over a 32 ha forest area. The distribution of sites was skewed towards the lower end of the %CO gradient (0.5 to 12.8%), while species abundance sharply diminished at both ends of the gradient. Nevertheless, 15 out of 20 species had a non-random distribution in relation to %CO, with many species concentrated near the lower side of the gradient. The observed pattern of species’ overlap was within the 95% confidence limits for the average overlap expected under the bounded null model. These patterns indicate that low canopy openness is the rule in this forest, in spite of the scattered tree-fall gaps, and suggest that light partitioning does not determine the tree community structure at the juvenile stage. High redundancy in light requirements among juveniles of tree species may have a positive effect on species coexistence in cloud forests, thus maintaining a high species diversity. However, other factors such as recruitment limitation and differential growth/carbon-gain among species at the juvenile stage along the light gradient could contribute to the high diversity of these ecosystems.

Keywords: Natural Regeneration, Light Availability, Understory, Shade Tolerance, Hemispherical Photography, Null Models

iForest 9 (3): 363-369 (2016) - doi: 10.3832/ifor1568-008
https://iforest.sisef.org/contents/?id=ifor1568-008

Research Articles: Effect of Funneliformis mosseae on growth, mineral nutrition, biochemical indexes and chlorophyll content of Ziziphus spina-christi seedlings at different salinities

Mirzaei J, Mirzaei Y, Naji HR — 2015-12-08

Mirzaei J, Mirzaei Y, Naji HR

EFFECT OF FUNNELIFORMIS MOSSEAE ON GROWTH, MINERAL NUTRITION, BIOCHEMICAL INDEXES AND CHLOROPHYLL CONTENT OF ZIZIPHUS SPINA-CHRISTI SEEDLINGS AT DIFFERENT SALINITIES

Abstract: Vast area of the land around the world is saline. Knowledge of plant behavior and their interaction with mychorrizal fungi in saline areas may help seedling establishment in such environments. This study aimed to determine the effects of the inoculation of the fungus Funneliformis mosseae (FM) on Ziziphus spina-christi (Rhamnaceae) plants grown under salt stress. Mycorrhizal and non-mycorrhizal seedlings were exposed to different levels of NaCl in the soil (0, 50, 100, and 150 mM). The following parameters were measured in both inoculated and non-inoculated plants: root colonization rate, seedling height, root diameter, root and shoot dry weights, chlorophyll a and b, total nitrogen (N), phosphorus (P), potassium (K) and sodium (Na+) content, proline accumulation in roots and leaves, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities. The results showed that soil salinity hampered the root colonization by the fungus, and decreased basal diameter, seedling height, root and shoot dry weights, as well as some nutrients and chlorophyll a concentration, while increased leaves and roots Na+, SOD and POD activity, proline accumulation, as well as CAT activity in the roots. Contrastingly, no significant effect of soil salinity were detected on K and CAT of leaves, root N, and chlorophyll b. Inoculated plants had higher basal diameter, leaves and roots P, root and shoot dry weights, chlorophyll a and lower SOD content, proline accumulation in leaves and Na+, as compared with non-inoculated plants. Seedling height, root N, CAT and POD content, and chlorophyll b were not affected by inoculation with FM. These results demonstrated that FM inoculation is a promising method for improving the growth of Z. spina-christi seedlings under salt stress.

Keywords: Salinity, Peroxidase, Chlorophyll, Arbuscular Mycorrhiza, Ziziphus spina-christi

iForest 9 (3): 503-508 (2016) - doi: 10.3832/ifor1643-008
https://iforest.sisef.org/contents/?id=ifor1643-008

Research Articles: Inorganic and organic nitrogen uptake by nine dominant subtropical tree species

Li C, Li Q, Qiao N, Xu X, Li Q, Wang H — 2015-12-02

Li C, Li Q, Qiao N, Xu X, Li Q, Wang H

INORGANIC AND ORGANIC NITROGEN UPTAKE BY NINE DOMINANT SUBTROPICAL TREE SPECIES

Abstract: We explored inorganic and organic N uptake patterns by dominant tree species in a subtropical plantation of southern China to improve understanding of nitrogen (N) cycling in these forests. We labeled intact roots by brief 15N exposures in field hydroponic experiments. Nine dominant tree species were examined to compare the effects of functional plant group (conifers versus broadleaves), mycorrhizal types, and forest successional stages on N uptake. All investigated species took up glycine at lower rates than other N forms, with mean values of 2.55 ± 0.36 µg N g-1 d.w. root h-1. Nitrate uptake rates for all species (average 5.81 ± 0.35 µg N g-1 d.w. root h-1) were significantly lower than ammonium (36.86 ± 5.17 µg N g-1 d.w. root h-1). All investigated species absorbed ammonium for more than 80% of total N uptake. Nitrate acquisition by these species was about 14% of total N uptake, with only 6% for glycine. Conifers showed significantly higher uptake rates of glycine, but lower uptake of nitrate than broadleaves. Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) tree species showed significant difference in nitrate uptake, with higher rates by AM tree species. Tree species at late-successional forest stages showed higher uptake rates of nitrate than those in earlier successional stages. Our findings indicate that ammonium is the dominant N source and glycine is a minor N source throughout forest succession.

Keywords: Plant Functional Group, AM Fungi, ECM Fungi, N Uptake, Subtropical Tree Species, Succession

iForest 9 (2): 253-258 (2016) - doi: 10.3832/ifor1502-008
https://iforest.sisef.org/contents/?id=ifor1502-008

Research Articles: Estimation of stand crown cover using a generalized crown diameter model: application for the analysis of Portuguese cork oak stands stocking evolution

Paulo JA, Faias SP, Ventura-Giroux C, Tomé M — 2015-12-02

Paulo JA, Faias SP, Ventura-Giroux C, Tomé M

ESTIMATION OF STAND CROWN COVER USING A GENERALIZED CROWN DIAMETER MODEL: APPLICATION FOR THE ANALYSIS OF PORTUGUESE CORK OAK STANDS STOCKING EVOLUTION

Abstract: A generalized non-linear tree crown diameter model was developed with the aim of allowing the computation of tree crown diameter over a large range of tree dimensions, and allowing its inclusion in forest growth and yield models. The model was formulated to provide biological meaning to the predicted values. Due to the nested structure of the data analyzed (trees within stands), both mixed- and fixed-effect models were developed. Since tree crown diameter is not frequently measured in forest inventories, the validation of the mixed model was carried out by considering the population specific response. The results demonstrate that when the measurements required for the mixed model calibration are not available, the use of the fixed effect model results in less biased and more accurate estimates. The fixed model was applied to the data from the two last Portuguese National Forest Inventories (NFI) to analyze the change in stand crown cover and assess the stocking evolution of cork oak stands in Portugal between 1996 and 2006. Results showed an increase in the frequency of stands with crown cover lower than 20%, as well as a decrease in the frequency of stands with crown cover between 20 and 40%. Average crown cover values were significantly different in the two NFI, with a decrease from 28.0 to 26.5% over the considered period.

Keywords: Quercus suber, Stand Crown Cover, Tree Crown Diameter, Nonlinear Mixed Effects Model, Nonlinear Fixed Effects Model, Portuguese National Forest Inventory

iForest 9 (3): 437-444 (2016) - doi: 10.3832/ifor1624-008
https://iforest.sisef.org/contents/?id=ifor1624-008

Research Articles: Effects of understory removal on root production, turnover and total belowground carbon allocation in Moso bamboo forests

Tang X, Fan S, Qi L, Guan F, Liu G, Du M — 2015-11-20

Tang X, Fan S, Qi L, Guan F, Liu G, Du M

EFFECTS OF UNDERSTORY REMOVAL ON ROOT PRODUCTION, TURNOVER AND TOTAL BELOWGROUND CARBON ALLOCATION IN MOSO BAMBOO FORESTS

Abstract: Although the role of roots has been highlighted in carbon and nutrient cycles in forest ecosystems, root production, turnover and total belowground carbon allocation (TBCA) under different management regimes in Moso bamboo forests have not been determined to date. In this study, sequential soil cores were collected at two soil depths (0-20 cm and 20-40 cm) to assess the effects of understory removal on root production, turnover, and TBCA in Moso bamboo forests in subtropical China. A total of 1080 sequential soil cores were collected from April 2011 to March 2012. Understory removal significantly reduced fine root biomass and production for both soil layers (p < 0.05). Total fine root biomass was 781.9, 419.2, and 638.7 g m-2 for an unmanaged stand (stand I), pesticide-treated stand (stand II), and hand-weeded stand (stand III), and fine root production was 467.5, 235.1, and 321.6 g m-2 a-1, respectively. Understory removal did not significantly affect fine root turnover (0.5-0.6 a-1). Fine root turnover showed a strong relationship with fine root production, but not with fine root biomass, indicating that fine root production was the main driver of fine root turnover. TBCA calculated from the component cumulative approach was in order of stand I (481.9 g C m-2 a-1) > stand II (457.7 g C m-2 a-1) > stand III (404.9 g C m-2 a-1), though the differences were not statistically significant (p > 0.05). However, TBCA calculated from the mass balance approach showed a reverse trend compared to the component cumulative approach. The TBCA of stand III was significantly higher than that of stand I and stand II (p < 0.05), demonstrating that the belowground process is complex and standardizing the method of estimation of TBCA is extremely important in global carbon cycle modeling.

Keywords: Fine Root, Coarse Root, Production, TBCA, Moso Bamboo Forest

iForest 9 (2): 187-194 (2016) - doi: 10.3832/ifor1674-008
https://iforest.sisef.org/contents/?id=ifor1674-008

Research Articles: Rapid spread of a fleshy-fruited species in abandoned subalpine meadows - formation of an unusual forest belt in the eastern Carpathians

Durak T, Zywiec M, Kapusta P, Holeksa J — 2015-11-20

Durak T, Zywiec M, Kapusta P, Holeksa J

RAPID SPREAD OF A FLESHY-FRUITED SPECIES IN ABANDONED SUBALPINE MEADOWS - FORMATION OF AN UNUSUAL FOREST BELT IN THE EASTERN CARPATHIANS

Abstract: In recent decades, most subalpine hay meadows and pastures have been abandoned, and trees have been recolonizing these sites where forest existed before agricultural activity. This study examined how woody vegetation, dominated by the deciduous fleshy-fruited tree Sorbus aucuparia (rowan), expanded on subalpine meadows in the Western Bieszczady Mountains (eastern Carpathians, Poland) after the cessation of agricultural use. The aims were to determine the abundance of rowan in the woody vegetation, to estimate the rate of rowan expansion in the studied area, and to characterize the variability of rowan stands and growth forms. Rowan dominated the current plant community of abandoned subalpine meadows, though this species is not considered a rapid colonizer of open areas and was not frequent in the uppermost forest belt before the colonization. The whole area was encroached by rowans in a very short period of time 60-70 years ago. Rowan tree density was similar throughout the elevational gradient but the growth form changed, becoming more shrub-like with increasing elevation. Rowan stands will likely be the main element of the subalpine belt in this region in the upcoming decades. At present, no tree species can be considered a rapid successor to rowan in the area.

Keywords: Abandoned Subalpine Meadows, Forest Recolonization, Land Use Change, Subalpine Forest, Succession of Woody Vegetation

iForest 9 (2): 337-343 (2016) - doi: 10.3832/ifor1470-008
https://iforest.sisef.org/contents/?id=ifor1470-008

Research Articles: Public attitudes towards the use of transgenic forest trees: a cross-country pilot survey

2015-11-20

Kazana V, Tsourgiannis L, Iakovoglou V, Stamatiou C, Alexandrov A, Araújo S, Bogdan S, Bozic G, Brus R, Bossinger G, Boutsimea A, Celepirović N, Cvrčková H, Fladung M, Ivankovic M, Kazaklis A, Koutsona P, Luthar Z, Máchová P, Malá J, Mara K, Mataruga M, Moravcikova J, Paffetti D, Paiva JA, Raptis D, Sanchez C, Sharry S, Salaj T, Šijačić-Nikolić M, Tel-Zur N, Tsvetkov I, Vettori C, Vidal N

PUBLIC ATTITUDES TOWARDS THE USE OF TRANSGENIC FOREST TREES: A CROSS-COUNTRY PILOT SURVEY

Abstract: Information on public attitudes towards the use of transgenic trees in forest plantations is important in the decision-making process and policy implementation for safe tree development, particularly at the EU level. In Europe, the use of transgenic forest trees is very limited and therefore such information is completely lacking. To address this issue within the FP0905 European COST Action on the Biosafety of Transgenic Forest Trees a pioneer cross-country pilot survey on public attitudes towards the use of transgenic forest trees was conducted using young population as a focus group. This was decided mainly because this focus group represents the future consumers, policy makers or developers. Specifically, the survey aimed to: i) assess the level of young people’s knowledge about transgenic forest trees, ii) identify issues of concern to them regarding the cultivation of transgenic forest trees and iii) explore whether they approve or disapprove of the use of transgenic forest trees in plantations. Purposive sampling was performed and university students of different disciplines were included in the research as sampling subjects. In total, 1868 completed questionnaires from 15 European and non-European countries were analyzed. The young educated people that took part in the survey appeared to approve of the use of transgenic forest trees in plantations and would be willing to buy forest transgenic products. The potential loss of biodiversity due to a risk of gene flow between transgenic and wild trees was seen as the safety issue of most concern when considering the commercial release of transgenic forest trees. However, a serious perceived lack of knowledge about potential benefits and risks of the cultivation of transgenic forest trees was recorded in most of the countries. K-means clustering was implemented on respondents’ positive responses to identify potential country patterns. No differences in patterns of public attitude towards the acceptance of the commercial growing of transgenic forest trees were observed between European and non-European countries. Extended research on public attitude issues towards the use of transgenic forest trees is strongly recommended as a basis for policy implementation on safe tree development.

Keywords: GM Forest Trees, Public Awareness, Public Acceptance, k-means Clustering, University Students

iForest 9 (2): 344-353 (2016) - doi: 10.3832/ifor1441-008
https://iforest.sisef.org/contents/?id=ifor1441-008

Research Articles: Fire occurrence zoning from local to global scale in the European Mediterranean basin: implications for multi-scale fire management and policy

Koutsias N, Allgöwer B, Kalabokidis K, Mallinis G, Balatsos P, Goldammer JG — 2015-11-12

Koutsias N, Allgöwer B, Kalabokidis K, Mallinis G, Balatsos P, Goldammer JG

FIRE OCCURRENCE ZONING FROM LOCAL TO GLOBAL SCALE IN THE EUROPEAN MEDITERRANEAN BASIN: IMPLICATIONS FOR MULTI-SCALE FIRE MANAGEMENT AND POLICY

Abstract: This study proposes and evaluates a relatively new concept for fire occurrence zoning based on documented historical fire records. The proposed method creates continuous kernel density surfaces based on wildland fire ignition observations. Kernels have the advantage of directly producing density estimates that are not influenced by grid size or localization effects. Within this scheme, kernel density surfaces have been created and reclassified to construct fire occurrence zones at local to global scales in the Mediterranean Basin. Specifically, fire occurrence zones were created for the European scale (European Mediterranean Basin), national scale (Greece), regional scale (Peloponnese, Greece) and local scale (Chalkidiki, Greece). To evaluate fire occurrence zones, we compared the observed with the expected distribution of the number of fires within these zones using a Monte Carlo randomization test, finding that these numbers were statistically different in all cases. The deviations observed from the expected distributions towards the high occurrence zone indicated their successful assessment and value. In this paper, we further discuss their potential role and use for multi-scale fire management and policy in a European context.

Keywords: Fire Occurrence Zones, Kernel Density Interpolation, Local Scale, Regional Scale, National Scale, European Scale, Greece

iForest 9 (2): 195-204 (2016) - doi: 10.3832/ifor1513-008
https://iforest.sisef.org/contents/?id=ifor1513-008

Research Articles: Ectomycorrhizal fungal community associated with autochthonous white poplar from Serbia

Katanić M, Grebenc T, Orlović S, Matavuly M, Kovačević B, Bajc M, Kraigher H — 2015-11-12

Katanić M, Grebenc T, Orlović S, Matavuly M, Kovačević B, Bajc M, Kraigher H

ECTOMYCORRHIZAL FUNGAL COMMUNITY ASSOCIATED WITH AUTOCHTHONOUS WHITE POPLAR FROM SERBIA

Abstract: We analyzed the community of ectomycorrhizal fungi of an autochthonous white poplar (Populus alba L.) stand in the Kovilj-Petrovaradin marshes (Serbia), and examined its seasonal dynamics. Ectomycorrhizal types were identified by combining morphological and anatomical descriptions with molecular methods (sequencing of ITS region of ribosomal DNA). In two seasons, 20 ectomycorrhizal types were recorded, from which 11 types were identified to the species level, six were determined to the genus level, two types were determined to the family level and one type remained unidentified. Number of ectomycorrhizal types, number of fine roots, percentage of vital mycorrhizal roots, diversity indexes and abundance of exploration types did not differ significantly between autumn and spring. During both seasons, the most abundant types were: Entoloma sp., Tuber maculatum, Cenococcum geophilum, Tuber rufum and Peziza sp. Due to the high variation of the ectomycorrhizal types-based Shannon-Weaver diversity index in poplar stands, and the fact that poplars form dual mycorrhizal association, this index is not recommended as a reliable index for bioindication in poplar.

Keywords: Ectomycorrhiza, Populus alba, Diversity, Nature Reserve, Seasonal Dynamics, Morphological-Anatomical Characterization, Molecular Identification

iForest 9 (2): 330-336 (2016) - doi: 10.3832/ifor1370-008
https://iforest.sisef.org/contents/?id=ifor1370-008

Research Articles: Variation in resistance to the rust fungus Melampsora larici-populina Kleb. in Populus nigra L. in the Czech Republic

Štochlová P, Novotná K, Benetka V — 2015-10-26

Štochlová P, Novotná K, Benetka V

VARIATION IN RESISTANCE TO THE RUST FUNGUS MELAMPSORA LARICI-POPULINA KLEB. IN POPULUS NIGRA L. IN THE CZECH REPUBLIC

Abstract: Differences in Populus nigra L. clone resistance to the rust fungus Melampsora larici-populina Kleb. (MLP) were studied in field trials where infected trees were compared with fungicide-protected trees. MLP rust infections were assessed using a 6-point scale. Four parameters of poplar growth were also measured to gauge host response to infection: shoot thickness, shoot number at the end of the growing season, individual plant dry weight, and dry matter yield per unit area. Five of eight known pathogen virulence types were detected. Cumulative growth in shoot thickness in sprayed and unsprayed plots was similar in clones with high rust pathogen resistance, but significantly different in clones with low resistance. Clones with low resistance also exhibited delayed growth initiation in the year following infection, an effect attributed to lower food storage accumulated during the previous year, reflected in a reduction in stem diameter. Based on stem thickness measurements, it was confirmed growth ceased at the end of August. Average rust severity symptoms ranged from 2.75 to 4.22 on the 6-point scale. The percentage reduction for the various growth parameters resulting from rust infection ranged as follows: individual plant dry weight 5-64%; dry matter yield 21-66%; shoot number 17-46%; and stem diameter 1-35%. Exclusive of stem diameter, these reductions correlated with severity in MLP rust infection. The one exception was tolerance to rust infection displayed by one of the clones. Clones with the lowest growth reductions were 97/152 and 97/157. Growth and yield parameter variation as a result MLP resistance difference was observed among tested P. nigra clones. This variation can be viewed as confirmation that resistance observed in this study and P. nigra clones is a suite of quantitative traits. These findings have important implications for MLP resistance breeding programs.

Keywords: Stem diameter, Pathogen effects, Pathogen tolerance, Melampsora larici-populina virulence, Field infection

iForest 9 (1): 146-153 (2016) - doi: 10.3832/ifor1458-008
https://iforest.sisef.org/contents/?id=ifor1458-008

Review Papers: The forest biodiversity artery: towards forest management for saproxylic conservation

Mason F, Zapponi L — 2015-10-26

Mason F, Zapponi L

THE FOREST BIODIVERSITY ARTERY: TOWARDS FOREST MANAGEMENT FOR SAPROXYLIC CONSERVATION

Abstract: One of the objectives of forest conservation is the set aside of unharvested areas. However, the fragmentation and lack of connectivity of protected areas make the integration of conservation measures in productive forests essential. Strategies to integrate conservation of saproxylic biodiversity in forest management have been developed, but often considering only specific aspects or remaining preliminary otherwise. As the impact of climate change and anthropogenic stresses increases, the development and the synthesis of this approach is crucial. We reviewed the key literature on forest management for biodiversity conservation, integrating forest science perspective to provide a practical management framework. Our goal is to present a management framework that could contribute to the effective preservation of forest insect biodiversity at the landscape scale, without high economic efforts, and addressing the conflicts that still jeopardize sustainable forest management. The results of our review support the creation of micro-reserves inside productive forests, to support large reserves in landscape conservation strategies. Micro-reserves increase the resilience of forest ecosystems to anthropogenic disturbances, through the development of a heterogeneous structure, maximizing microhabitat availability. Modeling forest management and harvest on local natural disturbance would extend the benefits of spatio-temporal heterogeneity in productive forests. Variable retention harvest systems, applied at the landscape scale, are a feasible and adaptable strategy to preserve and increase biodiversity, safeguarding structural legacies such as senescent trees and deadwood inside the productive matrix. The operational shift, from the stand to the forest landscape, is fundamental to extend the benefits of conservation measures. The Forest Biodiversity Artery, composed by several micro-reserves or îlots de senescence, connected by corridors of habitat trees and deadwood, constitutes a network that would deliver old-growth forests attributes to the productive matrix. This planning instrument would support forest connectivity, and socioeconomic constraints.

Keywords: Biodiversity, Deadwood, Gap, Habitat Tree, Integrative Conservation, Landscape, Microhabitat, Retention

iForest 9 (2): 205-216 (2016) - doi: 10.3832/ifor1657-008
https://iforest.sisef.org/contents/?id=ifor1657-008

Research Articles: Adaptability of Indocalamus decorus to climate change based on physiological and biochemical responses to elevated carbon dioxide and ozone

Guo Z, Zhuang M, Li Y, Chen S, Yang Q — 2015-10-22

Guo Z, Zhuang M, Li Y, Chen S, Yang Q

ADAPTABILITY OF INDOCALAMUS DECORUS TO CLIMATE CHANGE BASED ON PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES TO ELEVATED CARBON DIOXIDE AND OZONE

Abstract: Carbon dioxide (CO2) and ozone (O3) are important greenhouse gases that contribute to global climate change. The effects of elevated CO2 and/or O3 on plants remain unclear. Plant responses to mixtures of the two gases at high concentrations are likely to be complex. Previous studies have shown that the ability to tolerate elevated levels of the two gases varies among plant species; physiological adaptability in the face of changing atmospheric composition also differs among taxa. However, the effects of mixtures of the two greenhouse gases on the growth and physiology of bamboo are largely unexplored, even though bamboos are important vegetation elements throughout tropical and subtropical regions of the planet. In this study, we used open-topped chambers (OTC) to double the concentrations of atmospheric CO2 and O3, and examined changes in membrane lipid peroxidation, photosynthetic physiology, and antioxidase activities in Indocalamus decorus leaves. After 103 days of treatment, elevated O3 depressed net photosynthetic rate (Pn) without changing stomatal function, but caused no significant oxidative damage in the leaves. High levels of antioxidase activities were maintained in the leaves, indicating that this species had a strong tolerance to elevated O3. Decreases in reactive oxygen content and antioxidase activity in the leaves highlighted the significant positive effects of elevated CO2 on photosynthesis in I. decorus. When a mixture of both gases was supplied at high concentrations, we detected no oxidative damage, although photosynthetic capacity was reduced. Negative effects of O3 were very marked during the early part of the treatment period, but the effects of CO2 were positive. CO2 mitigated the oxidative damage caused by O3 and promoted the growth of I. decorus. Thus, I. decorus tolerated the two greenhouse gases, and was able to adapt to elevated CO2 and O3 levels. These findings contribute to the current knowledge base on the response of bamboo to global climate change.

Keywords: Antioxidant Enzyme, Carbon Dioxide, Indocalamus decorus, Membrane Lipid Peroxidation, Ozone, Photosynthetic Physiology

iForest 9 (2): 311-317 (2016) - doi: 10.3832/ifor1571-008
https://iforest.sisef.org/contents/?id=ifor1571-008

Research Articles: Effects of different silvicultural measures on plant diversity - the case of the Illyrian Fagus sylvatica habitat type (Natura 2000)

Kutnar L, Eler K, Marinšek A — 2015-10-22

Kutnar L, Eler K, Marinšek A

EFFECTS OF DIFFERENT SILVICULTURAL MEASURES ON PLANT DIVERSITY - THE CASE OF THE ILLYRIAN FAGUS SYLVATICA HABITAT TYPE (NATURA 2000)

Abstract: In Slovenia, the Natura 2000 network covers more than 37% of the country. Forests dominate more than 70% of this area, and forest management is a significant driver of diversity. Depending on the options applied, forest management may enhance or decrease forest biodiversity. Dinaric fir-beech forests (part of Natura 2000 habitat type) with remarkable nature-conservation interest and timber production functions were selected for this study. With the aim of testing the effects of different silvicultural measures on plant diversity in these forests, and consequently on biodiversity in a broader sense, three sites in the Slovenian part of a Dinaric fir-beech forest range were studied. The plant species diversity was assessed before and after the implementation of silvicultural measures of three intensities: (1) control plots - no logging; (2) logging of 50% of the growing stock; and (3) logging of 100% of the growing stock. Before the implementation of the silvicultural measures, the mean number of plant species per 400 m² vegetation plots was 48.8, and the mean value of the Shannon’s diversity index was 2.41. Two years after the measures were implemented, different magnitudes of plant species turnover were observed. There were no significant changes in plant diversity status and vegetation composition in the control plots. Two years after 50% of the growing stock was logged, the mean number of species was 73.3, and the mean value of the Shannon index was 3.21. In the plots where all the trees were removed, the mean number of species was 87.4, and the mean value of the Shannon index was 3.42. In parallel with the increases in the diversity parameters, the cover of the herbaceous layer increased significantly with an increase in the silvicultural intensity, indicating that short-term species turnover can mostly be attributed to herbaceous plant species. As a result of changed stand and ecological conditions, an increased plant diversity, a greater biodiversity in a broader sense and an improved habitat suitability for different animal species could be expected.

Keywords: Forest Management, Silviculture, Nature Conservation, Plant Diversity, Species Turnover, Gap Colonization, Mountain Forest, Dinaric Fir-beech Forest, Natura 2000

iForest 9 (2): 318-324 (2016) - doi: 10.3832/ifor1587-008
https://iforest.sisef.org/contents/?id=ifor1587-008

Short Communications: Effect of intensive planting density on tree growth, wood density and fiber properties of maple (Acer velutinum Boiss.)

Naji HR, Nia MF, Kiaei M, Abdul-Hamid H, Soltani M, Faghihi A — 2015-10-22

Naji HR, Nia MF, Kiaei M, Abdul-Hamid H, Soltani M, Faghihi A

EFFECT OF INTENSIVE PLANTING DENSITY ON TREE GROWTH, WOOD DENSITY AND FIBER PROPERTIES OF MAPLE (ACER VELUTINUM BOISS.)

Abstract: Planting density is a major factor in determining tree growth and wood quality. Although the effect of low planting density on the variation of tree and wood characteristics has been already reported, the effect of intensive initial densities in plantations has not been fully assessed yet. In this study, the effect of intensive planting densities on tree growth, wood density and fiber cell properties was investigated in the context of the development of densely-stocked maple plantations for wood production. The study was carried out in a 12-year-old Acer velutinum trial plantation in northern Iran, with initial densities of 10000, 4444, and 2500 trees ha-1 planted. The variation of diameter at breast height, annual ring width, stem taper, wood density, and fiber cell properties were examined. As expected, low planting densities showed trees with larger diameter at breast height and annual ring width. The largest trees at higher densities were smaller than those in lower planting densities. However, initial planting density had no significant effect on stem taper, wood density and fiber cell properties. In addition, no significant relationships between tree growth features and wood properties were detected, indicating similar wood properties at all planting densities. Therefore, stand/tree growth attributes under intensive planting densities could not be considered as reliable predictors of the wood properties.

Keywords: Initial Spacing, Annual Ring Width, Wood Density, Fiber Properties, Acer velutinum

iForest 9 (2): 325-329 (2016) - doi: 10.3832/ifor1333-008
https://iforest.sisef.org/contents/?id=ifor1333-008

Research Articles: Availability of tree cavities in a sal forest of Nepal

2015-10-16

Bhusal P, Czeszczewik D, Walankiewicz W, Churski M, Baral R, Lamichhane BR, Mikusinski G

AVAILABILITY OF TREE CAVITIES IN A SAL FOREST OF NEPAL

Abstract: Tree cavities are important structural elements of forest ecosystem that host numerous birds, mammals and other cavity-dependent organisms. Pattern of cavity distribution in temperate and boreal forests are relatively well studied, yet little is known about cavities in tropical and subtropical forests. We compared cavity availability in relation to tree condition (living tree and snag), tree species and DBH class between two different sites in a subtropical deciduous sal forest in Nepal: the Chitwan National Park Forest (the park site) and the Khorsor Buffer Zone Forest (the buffer site). Surveys for tree cavities were conducted in 2013 on 50 circular sample plots of size 0.1 ha. We recorded 40 cavity trees in the park site and 31 cavity trees in the buffer site. Density of cavities was on average 22.4 ha-1 in the park site and 19.2 ha-1 in the buffer site. Cavities occurred mostly in living trees (85.9% cavity trees) and were formed mostly by damage and decay (natural cavities: 74%) or by woodpecker activity (excavated cavities: 26%). Most were observed on three tree species: Shorea robusta, Dillenia pentagyna and Syzygium operculatum, with a mean diameter of 43 cm (range: 12-111 cm). S. operculatum, Myrsine semiserrata and Semecarpus anacardium were overrepresented among tree species with cavities. In snags, 25.0% of all cavities were found in the park site and 8.3% in the buffer site, while snags represented 4.2% and 2.2% of all trees in the two sites, respectively. Statistical anaysis indicated that tree species, tree condition and particularly diameter (DBH) were important variables for the prediction of cavity presence. We recommend cavity-bearing tree species to be better protected by forest management in order to help maintain the community of cavity dwellers.

Keywords: Chitwan National Park, Natural Cavities, Excavated Cavities, Subtropical Forest, Tree Holes

iForest 9 (2): 217-225 (2016) - doi: 10.3832/ifor1493-008
https://iforest.sisef.org/contents/?id=ifor1493-008

Research Articles: Sensitivity of European beech trees to unfavorable environmental factors on the edge and outside of their distribution range in northeastern Europe

2015-10-16

Augustaitis A, Kliučius A, Marozas V, Pilkauskas M, Augustaitiene I, Vitas A, Staszewski T, Jansons A, Dreimanis A

SENSITIVITY OF EUROPEAN BEECH TREES TO UNFAVORABLE ENVIRONMENTAL FACTORS ON THE EDGE AND OUTSIDE OF THEIR DISTRIBUTION RANGE IN NORTHEASTERN EUROPE

Abstract: European beech is a successful tree species outside its distribution range in northeastern Europe, where Prussian foresters introduced it mainly into Scots pine stands. This forest management practice resulted in new issues related to the sensitivity of European beech to current environmental changes in areas outside its natural range. We hypothesized that recent global environmental changes promoted the northeast migration of European beech outside its distribution range in Europe. To test this hypothesis, dendrochronological analysis of beech tree ring series was performed for eight sites located in Poland, Lithuania and Latvia. Frost in winter months and heat in June, along with drought in the vegetation period, limited beech tree growth outside its natural distribution range in northeast Europe. Higher air concentration of surface ozone and sulphur deposition level reinforced the negative effect of the detected key meteorological variables on beech growth, while higher air concentrations and deposition of nitrate had a positive effect. These factors explained about 50% of the total variation in increment indexes of beech trees at sites on the northeasren edge of their range. The observed trends of beech growth over the last 25 years has determined favorable conditions for planting this tree species outside its natural range in northeastern European forests.

Keywords: European Beech, Tree Increment Indexes, Meteorological Parameters, Ozone, Acidifying Compounds

iForest 9 (2): 259-269 (2016) - doi: 10.3832/ifor1398-008
https://iforest.sisef.org/contents/?id=ifor1398-008

Research Articles: Impact of climate change on tree-ring growth of Scots pine, common beech and pedunculate oak in northeastern Germany

Bauwe A, Jurasinski G, Scharnweber T, Schröder C, Lennartz B — 2015-10-13

Bauwe A, Jurasinski G, Scharnweber T, Schröder C, Lennartz B

IMPACT OF CLIMATE CHANGE ON TREE-RING GROWTH OF SCOTS PINE, COMMON BEECH AND PEDUNCULATE OAK IN NORTHEASTERN GERMANY

Abstract: Tree growth depends, among other factors, largely on the prevailing climatic conditions. Therefore, changes to tree growth patterns are to be expected under climate change. Here, we analyze the tree-ring growth response of three major European tree species to projected future climate across a climatic (mostly precipitation) gradient in northeastern Germany. We used monthly data for temperature, precipitation, and the standardized precipitation evapotranspiration index (SPEI) over multiple time scales (1, 3, 6, 12, and 24 months) to construct models of tree-ring growth for Scots pine (Pinus sylvestris L.) at three pure stands, and for common beech (Fagus sylvatica L.) and pedunculate oak (Quercus robur L.) at three mature mixed stands. The regression models were derived using a two-step approach based on partial least squares regression (PLSR) to extract potentially well explaining variables followed by ordinary least squares regression (OLSR) to consolidate the models to the least number of variables while retaining high explanatory power. The stability of the models was tested through a comprehensive calibration-verification scheme. All models were successfully verified with R²s ranging from 0.21 for the western pine stand to 0.62 for the beech stand in the east. For growth prediction, climate data forecasted until 2100 by the regional climate model WETTREG2010 based on the A1B Intergovernmental Panel on Climate Change (IPCC) emission scenario was used. For beech and oak, growth rates will likely decrease until the end of the 21st century. For pine, modeled growth trends vary and range from a slight growth increase to a weak decrease in growth rates. The climatic gradient across the study area will possibly affect the future growth of oak with larger growth reductions towards the drier east. For beech, site-specific adaptations seem to override the influence of the climatic gradient. We conclude that Scots pine has great potential to remain resilient to projected climate change without any greater impairment, whereas common beech and pedunculate oak will likely face lesser growth under the expected warmer and dryer climate conditions. The results call for an adaptation of forest management to mitigate the negative effects of climate change for beech and oak.

Keywords: Partial Least Squares Regression (PLSR), Precipitation Gradient, Tree-ring Growth Forecast, Standardized Precipitation Evapotranspiration Index (SPEI), Tree Rings, WETTREG

iForest 9 (1): 1-11 (2016) - doi: 10.3832/ifor1421-008
https://iforest.sisef.org/contents/?id=ifor1421-008

Research Articles: Leaf transpiration of drought tolerant plant can be captured by hyperspectral reflectance using PLSR analysis

Wang Q, Jin J — 2015-10-05

Wang Q, Jin J

LEAF TRANSPIRATION OF DROUGHT TOLERANT PLANT CAN BE CAPTURED BY HYPERSPECTRAL REFLECTANCE USING PLSR ANALYSIS

Abstract: A clear understanding of plant transpiration is a crucial step for water cycle and climate modeling, especially for arid ecosystems in which water is one of the major constraints. Traditional field measurements of leaf scale transpiration are always time-consuming and often unfeasible in the context of large spatial and temporal scales. This study focused on a dominant native plant in the arid land of central Asia, Haloxylon ammondendron, with the aim of deriving the leaf-scale transpiration through hyperspectral reflectance using Partial Least Squares Regression (PLSR) analysis. The results revealed that the PLSR model based on the first-order derivative spectra at wavelengths selected through stepwise regression analysis can closely trace leaf transpiration with a high accuracy (R2 = 0.78, RMSE = 1.62 µmol g-1 s-1). The accuracy is also relatively stable even at a spectral resolution of 10 nm, which is very close to the bandwidths of several running satellite-borne hyperspectral sensors such as Hyperion. The results also proved that the first-order derivative spectra within the shortwave infrared (SWIR) domain, especially at 2435, 2440, 2445, and 2470 nm, were critical for PLSR models to predict leaf transpiration. These findings highlight a promising strategy for developing remote sensing methods to potentially characterize transpiration at broad scales.

Keywords: Arid Land, Leaf Transpiration, PLSR, Derivative Spectra, Drought-tolerant, Haloxylon ammondendron

iForest 9 (1): 30-37 (2016) - doi: 10.3832/ifor1634-008
https://iforest.sisef.org/contents/?id=ifor1634-008

Research Articles: Effect of plant species on P cycle-related microorganisms associated with litter decomposition and P soil availability: implications for agroforestry management

Correa E, Carvalhais L, Utida M, Oliveira CA, Scotti MR — 2015-10-05

Correa E, Carvalhais L, Utida M, Oliveira CA, Scotti MR

EFFECT OF PLANT SPECIES ON P CYCLE-RELATED MICROORGANISMS ASSOCIATED WITH LITTER DECOMPOSITION AND P SOIL AVAILABILITY: IMPLICATIONS FOR AGROFORESTRY MANAGEMENT

Abstract: Cutting dry deciduous forest (preserved site) for wood supply in semi-arid Brazil has led to invasion of a pioneer shrub vegetation called “Carrasco” (disturbed site), which inhibits the sprouting of native species. A land restoration project was undertaken in a cleared Carrasco area where a mixed plantation of native species and Eucalyptus spp. (experimental site) was established to preserve the forest and ensure wood supply for the local population. We considered phosphorus as a limiting soil nutrient to plant growth, and we addressed the roles of litter decomposition and microbial activity on phosphorus release in the disturbed, preserved and experimental sites. The phosphorus released from leaf litter was affected by the vegetation type, which favored specific soil microbial populations during decomposition. The Carrasco vegetation predominantly favored arbuscular mycorrhizal fungi (AMF), as shown by root colonization in the litter bags; the Eucalyptus plants favored AMF and ectomycorrhizal fungi (EM), as well as phosphate solubilizing microorganisms (PSM), and the intercropping system favored AMF and PSM groups. In contrast, the preserved site favored the PSM population. High phosphatase activity was found in the preserved and experimental sites in contrast to the Carrasco soil. Principal component analysis showed that AMF root colonization and phosphatase activity were the main parameters influencing the increase in soil phosphorus. Based on the above results, rehabilitation appeared to be underway in the experimental site, since the samples were more similar to the preserved site than to the disturbed site. This effect was attributed to Eucalyptus camaldulensis that promote the establishment of all phosphorus cycle-related microorganisms (AMF, EM and PSF). E. camaldulensis associated with mycorrhizal fungi and PSM are recommended for inclusion in agroforestry systems.

Keywords: Agroforestry System, Arbuscular Mycorrhizal Fungi, Land Restoration, Litter Decomposition, Phosphate Solubilizing Microorganisms, Soil Phosphorus

iForest 9 (2): 294-302 (2016) - doi: 10.3832/ifor1459-008
https://iforest.sisef.org/contents/?id=ifor1459-008

Research Articles: Nutritional, carbon and energy evaluation of Eucalyptus nitens short rotation bioenergy plantations in northwestern Spain

González-García M, Hevia A, Majada J, Rubiera F, Barrio-Anta M — 2015-10-05

González-García M, Hevia A, Majada J, Rubiera F, Barrio-Anta M

NUTRITIONAL, CARBON AND ENERGY EVALUATION OF EUCALYPTUS NITENS SHORT ROTATION BIOENERGY PLANTATIONS IN NORTHWESTERN SPAIN

Abstract: This study provides essential information related to the nutrient and carbon levels and the energy potential of Eucalytpus nitens (Deane & Maiden) Maiden bionenergy plantations located in northwestern Spain. Nutritional analysis showed that leaves and bark had the highest concentrations of N, P, K and Mg. Carbon concentration was constant for all above-ground tree components. Nutrients and carbon were analyzed at stand level according to plantation productivity. Stemwood, the main tree component at the end of the rotation, had the highest nutrient content, except for N and Ca, which were highest in leaves and bark respectively. Based on this study, the nutrient content per ha of above-ground biomass was 243-706 kg N, 44-122 kg P, 131-375 kg K, 121-329 kg Ca and 25-67 kg Mg at the end of the bioenergy rotation (6-12 years, depending on site quality) and 19-56 Mg C ha-1. Energy analysis showed a fairly constant Net Calorific Value for wood, 18.32 ± 0.19 MJ kg-1. The results obtained are valuable for selecting the most appropriate forest management system in these bioenergy plantations, and thereby promote the sustainable use of woody crops.

Keywords: Eucalyptus, Woody Crops, Bioenergy, Site Quality, Nutrient, Carbon, Energy Potential, Calorific Value

iForest 9 (2): 303-310 (2016) - doi: 10.3832/ifor1505-008
https://iforest.sisef.org/contents/?id=ifor1505-008

Research Articles: Dead wood quality influences species diversity of rare cryptogams in temperate broadleaved forests

Preikša Z, Brazaitis G, Marozas V, Jaroszewicz B — 2015-09-28

Preikša Z, Brazaitis G, Marozas V, Jaroszewicz B

DEAD WOOD QUALITY INFLUENCES SPECIES DIVERSITY OF RARE CRYPTOGAMS IN TEMPERATE BROADLEAVED FORESTS

Abstract: Dead wood is one of the most important indicators of forest naturalness and the most important manageable habitat for biodiversity in forests. Standing and lying dead wood, and especially coarse woody debris, plays an important part in creating habitats for many highly specialized organisms, e.g., insects, fungi, lichens and bacteria. Temperate mixed deciduous forests, rich in species, have been studied only to a small extent from the point of view of the ecology of wood-related cryptogams. Our study aimed at the reduction of the gap in knowledge about the ecological characteristics of dead wood-dependent organisms by focusing on species of cryptogams developing on various dead wood structures typical of temperate non-beech forests. Studies were performed in forests located in Lithuania, Poland, Belarus and Russia. We recorded 48 species of cryptogams: 18 species of bryophytes, 24 species of fungi and 6 species of lichens developing on dead wood. Our study stresses the importance of all types of dead wood as a substrate for the development of rare cryptogam species. Logs were the most important substratum type for cryptogams, followed by snags, dead trees and stumps. The cryptogam species richness on logs was several times higher than on the three other types of substrata. Coarse logs of intermediate decay stages hosted the highest number of cryptogams, followed by freshly fallen logs and, finally, well decayed logs. Assessing the importance of dead wood quality for the studied cryptogams, we found that intermediate decay stages are extremely important for fungi, while bryophytes or lichens do not show a clear preference. The highest number of cryptogams was found on Fraxinus excelsior, Quercus robur and Picea abies, while other tree species had less than half cryptogam species.

Keywords: Macrolichens, Fungi, Bryophytes, Tree Species, Indicator Species, Decay Stages

iForest 9 (2): 276-285 (2016) - doi: 10.3832/ifor1483-008
https://iforest.sisef.org/contents/?id=ifor1483-008

Research Articles: Climatic fluctuations trigger false ring occurrence and radial-growth variation in teak (Tectona grandis L.f.)

Palakit K, Duangsathaporn K, Siripatanadilok S — 2015-09-28

Palakit K, Duangsathaporn K, Siripatanadilok S

CLIMATIC FLUCTUATIONS TRIGGER FALSE RING OCCURRENCE AND RADIAL-GROWTH VARIATION IN TEAK (TECTONA GRANDIS L.F.)

Abstract: The objective of this study was to examine the interaction of extreme growth years in teak (Tectona grandis) with climatic conditions of current, antecedent and subsequent years, in order to explain the nature and the effects of climatic variability on teak growth in northeastern Thailand. A 33-year tree-ring index was constructed and extreme growth years during the period 1976-2008 were identified. A superposed epoch analysis (SEA) was used to study the interaction of climatic data and extreme growth years. Extreme growth years were derived from eight wider and seven narrower annual rings identified using the Cropper’s method. Seventeen false rings were detected using the threshold value ≥ 80% of false ring occurrence for all samples in each growth year. False ring occurrence was associated with narrow ring width formation and triggered by increasing maximum and mean temperatures at the beginning of the rainy season (May to August). In the third year after false ring formation, we observed a pattern of wet year occurrence when annual rainfall and relative humidity in September to December were higher than in adjacent years. Moreover, in the sixth year before false ring formation, a wet year was observed when relative humidity in September to December was higher than in adjacent years. Wider ring width index occurring in a particular year was found to be triggered by a decrease in maximum and mean temperatures in May to August of the current year, suggesting that wet years promote teak growth. The third year after the formation of wider rings was characterized by a low annual rainfall. Our results showed that drought years trigger false ring and narrow ring formation, while wet years trigger wide ring formation in teak. A cycle of wet years between the sixth year prior to, and the third year after, the formation of false rings was also observed, as well as the occurrence of drought in the third year since the formation of wide rings. False ring, narrow ring and wide ring occurrences appear to be good indicators of a 3-6 year climate fluctuation pattern, similar to that of the El Niño-Southern Oscillation (ENSO) cycle in this region.

Keywords: Extreme Event, False Ring, Pointer Year, Superposed Epoch Analysis, Teak (Tectona grandis), Tree-ring

iForest 9 (2): 286-293 (2016) - doi: 10.3832/ifor1100-008
https://iforest.sisef.org/contents/?id=ifor1100-008

Research Articles: Estimating biomass of mixed and uneven-aged forests using spectral data and a hybrid model combining regression trees and linear models

2015-09-21

López-Serrano PM, López-Sánchez CA, Díaz-Varela RA, Corral-Rivas JJ, Solís-Moreno R, Vargas-Larreta B, Álvarez-González JG

ESTIMATING BIOMASS OF MIXED AND UNEVEN-AGED FORESTS USING SPECTRAL DATA AND A HYBRID MODEL COMBINING REGRESSION TREES AND LINEAR MODELS

Abstract: The Sierra Madre Occidental mountain range (Durango, Mexico) is of great ecological interest because of the high degree of environmental heterogeneity in the area. The objective of the present study was to estimate the biomass of mixed and uneven-aged forests in the Sierra Madre Occidental by using Landsat-5 TM spectral data and forest inventory data. We used the ATCOR3® atmospheric and topographic correction module to convert remotely sensed imagery digital signals to surface reflectance values. The usual approach of modeling stand variables by using multiple linear regression was compared with a hybrid model developed in two steps: in the first step a regression tree was used to obtain an initial classification of homogeneous biomass groups, and multiple linear regression models were then fitted to each node of the pruned regression tree. Cross-validation of the hybrid model explained 72.96% of the observed stand biomass variation, with a reduction in the RMSE of 25.47% with respect to the estimates yielded by the linear model fitted to the complete database. The most important variables for the binary classification process in the regression tree were the albedo, the corrected readings of the short-wave infrared band of the satellite (2.08-2.35 µm) and the topographic moisture index. We used the model output to construct a map for estimating biomass in the study area, which yielded values of between 51 and 235 Mg ha-1. The use of regression trees in combination with stepwise regression of corrected satellite imagery proved a reliable method for estimating forest biomass.

Keywords: Regression Trees, Stepwise Regression, Remote Sensing, ATCOR3, Terrain Features, Image Texture

iForest 9 (2): 226-234 (2016) - doi: 10.3832/ifor1504-008
https://iforest.sisef.org/contents/?id=ifor1504-008

Research Articles: Genetic variation of Fraxinus excelsior half-sib families in response to ash dieback disease following simulated spring frost and summer drought treatments

Pliura A, Lygis V, Marčiulyniene D, Suchockas V, Bakys R — 2015-09-08

Pliura A, Lygis V, Marčiulyniene D, Suchockas V, Bakys R

GENETIC VARIATION OF FRAXINUS EXCELSIOR HALF-SIB FAMILIES IN RESPONSE TO ASH DIEBACK DISEASE FOLLOWING SIMULATED SPRING FROST AND SUMMER DROUGHT TREATMENTS

Abstract: Ten juvenile Fraxinus excelsior half-sib families from two Lithuanian populations have been tested in the controlled environment for their response to ash dieback disease caused by Hymenoscyphus fraxineus, detecting changes of genetic variation and heritability, as well as estimating genotype by environment (G×E) interaction and phenotypic plasticity following artificial spring frost and summer drought treatments. In 2014, a batch of 200 four-year-old ash seedlings was used for each treatment and control (no treatment). Health condition, bud flushing phenology and height were assessed for each seedling, and disease incidence and survival ratios were assessed for each family both before (at the beginning of the vegetation season) and after the treatments (at the end of the vegetation season). Disease incidence ratio increased from 0.77-0.80 up to 0.90-0.95. Tree mortality rates during one vegetation season were significantly lower in the frost treatment (21%) than in the drought treatment (25%) or control (31%). None of the tested F. excelsior families were completely resistant to ash dieback, although significant among-family differences in disease incidence and damage rates suggest an additive mode of gene action and thus a quantitative resistance to the disease. Neither disease incidence rates, nor tree health condition scores differed significantly among the applied treatments (including control) indicating in general a negligible effect of the simulated adverse conditions on health status of the ash seedlings. However, G×E interaction was found to be significant (at P > 0.05) for disease incidence, length of necrotic shoots and tree survival, implying that susceptibility of ash families to the dieback disease unequally depends on environmental conditions, and indicating a presence of genetic variation in plasticity and reaction norms of the tested families across environments (treatments). Substantially increased coefficients of additive genetic variation and heritability in health condition following both frost and drought treatments and compared to control showed that simulated stress conditions may noticeably contribute to expression of differences among the tested F. excelsior families in their resistance traits, thus enabling a better evaluation of performance of different families, an effective family selection for resistance, and achievement of a marked genetic gain.

Keywords: Common Ash, Dieback, Disease Resistance, Genetic Variation, Heritability, Hymenoscyphus pseudoalbidus (Chalara fraxinea), Phenotypic Plasticity

iForest 9 (1): 12-22 (2016) - doi: 10.3832/ifor1514-008
https://iforest.sisef.org/contents/?id=ifor1514-008

Research Articles: Stand structure and deadwood amount influences saproxylic fungal biodiversity in Mediterranean mountain unmanaged forests

2015-09-08

Persiani AM, Lombardi F, Lunghini D, Granito VM, Tognetti R, Maggi O, Pioli S, Marchetti M

STAND STRUCTURE AND DEADWOOD AMOUNT INFLUENCES SAPROXYLIC FUNGAL BIODIVERSITY IN MEDITERRANEAN MOUNTAIN UNMANAGED FORESTS

Abstract: Old-growth forests are key elements of ecosystem diversity and conservation strategies, providing niche differentiation and trophic pathways that produce structural and compositional heterogeneity. In these forests, deadwood is particularly important for saproxylic and mycorrhizal fungi, sustaining forest productivity and environmental services. In this study, the saproxylic fungal diversity in Mediterranean mountain forests, characterized by different management histories and forest types (holm oak and beech), was analyzed. The relationships between saproxylic fungal biodiversity and structural attributes were considered in three forest stands of the Apennines (Italy). In addition, descriptive environmental parameters and forest traits were related to prevailing fungal communities, in order to analyze the species composition and distribution patterns of saproxylic fungi resulting from the ordination processes. The study sites were selected on the basis of their late-serial stage of development. Species frequency was analyzed through multivariate techniques to test the relationships between fungi, structural attributes and environmental variables. A Detrended Correspondence Analysis (DCA) was used to investigate the response of the overall fungal community structure to environmental gradients. Living tree volume, altitude, vegetation type, and the frequency of species with ephemeral sporocarp lifespan played a crucial role in diversifying species distribution patterns. Deadwood volume and decay classes were related to taxonomic and trophic community diversity. However, differences between the considered climatic regions exerted a major role on the occurrence of fungi with ephemeral sporocarps more than deadwood abundance, utilized primarily as fructification substrate.

Keywords: Apennines Forests, Forest Biodiversity, Old-growth Forest, Saproxylic Fungi, Sporocarp Lifespan, Structural Heterogeneity

iForest 9 (1): 115-124 (2016) - doi: 10.3832/ifor1304-008
https://iforest.sisef.org/contents/?id=ifor1304-008

Research Articles: Variation of wood and bark density and production in coppiced Eucalyptus globulus trees in a second rotation

Miranda I, Pereira H — 2015-09-08

Miranda I, Pereira H

VARIATION OF WOOD AND BARK DENSITY AND PRODUCTION IN COPPICED EUCALYPTUS GLOBULUS TREES IN A SECOND ROTATION

Abstract: Coppiced Eucalyptus globulus trees with 18 years of age and in a second rotation were analysed in relation to wood and bark density in a spacing trial with five initial plant densities. A total of 25 stumps, with a variable number of stems per stump, from one to three, were analysed. A comparison was made to the previous first rotation single stem trees, also harvested at 18 years of age. The average wood basic density at breast height of the eucalypt coppiced trees was 567 kg m-3, with lower wood density for the closest spacings. The wood of coppiced Eucalyptus globulus trees was 2.5% less dense than that of the single stem trees in the first rotation (average 582 kg m-3). Within the tree, the wood density decreased from stump level to breast height level and then gradually increased until 11.3 m and then decreased slightly. The bark density was, on average, 473 kg m-3, ranging from 455 to 487 kg m-3. The mean bark density was comparable to the bark density in the first rotation. The average bark content was 17.4% of the stem volume, providing 25 to 52 ton ha-1. Compared to the first rotation, the average tree volume in the coppice was lower because the individual trees were smaller by 40 to 66%, while the estimated volume production per ha of the coppice was 1.1 to 1.8 times more due to the increased number of trees that were left in each stump.

Keywords: Eucalyptus globulus, Wood Density, Plant Density, Coppice, 1st Rotation

iForest 9 (2): 270-275 (2016) - doi: 10.3832/ifor1442-008
https://iforest.sisef.org/contents/?id=ifor1442-008

Research Articles: Decomposition of Norway spruce and European larch coarse woody debris (CWD) in relation to different elevation and exposure in an Alpine setting

2015-08-28

Petrillo M, Cherubini P, Sartori G, Abiven S, Ascher J, Bertoldi D, Camin F, Barbero A, Larcher R, Egli M

DECOMPOSITION OF NORWAY SPRUCE AND EUROPEAN LARCH COARSE WOODY DEBRIS (CWD) IN RELATION TO DIFFERENT ELEVATION AND EXPOSURE IN AN ALPINE SETTING

Abstract: To describe the decay stage of coarse woody debris (CWD) a five decay-class system has been introduced and it is currently the most commonly applied. This system is based on visual, geometric and tactile features of the wood in the field; however, a detailed chemical characterization is often missing. Furthermore, the driving mechanisms (particularly substrate quality vs. environmental conditions) of deadwood decay are controversially discussed. Consequently, we investigated how typical major and minor chemical parameters of wood were correlated with the decay stage. The decomposition patterns of Norway spruce (Picea abies (L.) Karst) and European larch (Larix decidua Mill.) CWD of an Alpine setting were analyzed, and how the chemical and physical parameters were affected by the substrate and environmental conditions was checked. Two altitudinal sequences, having a different exposure (north- vs. south-facing sites), were sampled. We measured main biochemical compounds (lignin and cellulose), physical properties (density and water content), element concentrations (C, N, P, K, Ca, Mg, Fe, Mn), and the carbon isotopic signature (δ13C) of living trees and CWD at five decomposition stages (decay classes). Most investigated wood physico-chemical parameters such as wood density, water content, lignin and cellulose and even minor constituents (N, Ca, Mg, P, Fe, Mn) correlated well to the five decay-class system. Some important components, such as the carbon concentration and δ13C, did not vary with increasing decomposition. Our hypothesis that the different substrate should be traceable during CWD decay had to be rejected, although some statistically significant chemical differences between larch and spruce were measured in the living trees. The chosen tree species were probably not different enough to be chemically traceable in the CWD. Already in decay class 1, these differences were zeroed. The site conditions (expressed by the different altitudes and exposure) influenced only some of the investigated parameters, namely lignin, the δ13C isotopic ratio and nutrients such as P, Ca and K.

Keywords: Deadwood, Alps, Norway Spruce, European Larch, Decomposition, Lignin, Nutrients, Carbon Isotopes

iForest 9 (1): 154-164 (2016) - doi: 10.3832/ifor1591-008
https://iforest.sisef.org/contents/?id=ifor1591-008

Research Articles: Fragmentation of Araucaria araucana forests in Chile: quantification and correlation with structural variables

Molina JR, Martín A, Drake F, Martín LM, Herrera MA — 2015-08-28

Molina JR, Martín A, Drake F, Martín LM, Herrera MA

FRAGMENTATION OF ARAUCARIA ARAUCANA FORESTS IN CHILE: QUANTIFICATION AND CORRELATION WITH STRUCTURAL VARIABLES

Abstract: Landscape fragmentation is one of the main threats to South American temperate forests due to population growth, conversion of native forests to plantations of exotic species and non-sustainable timber harvesting. The lack of forest connectivity can interfere with pollination, seed dispersal, biodiversity and landscape quality. Species with relatively limited seed dispersal are potentially more sensitive to the landscape fragmentation. Araucaria araucana (Mol.) K. Koch is a long-lived, slow-growing, relict conifer in South America’s temperate forests with large seeds possessing a limited dispersal range. The objective of the study was to identify priority areas for Araucaria conservation based on fragmentation quantification and correlation with structural variables and regeneration conditions. Results from the FRAGSTATS® and CONEFOR® software indicated that Araucaria connectivity has increased in sites located in the central Andean Range in comparison to other sites, because of reduced human and livestock pressure as well as the relative absence of commercial plantations. The proximity index ranged from 6.01 m to 34834.2 m, and the probability of connectivity has significantly increased (175663 ha) in the central Andean Range. Significant relationships were found between the Simpson’s index (or the probability of connectivity) and basal area, and between the mean largest patch index and crown diameter. The largest patch index (r = 0.6; p < 0.05) and the area-weighted mean proximity index (r = 0.767; p < 0.05) were the most important landscape metrics influencing Araucaria regeneration. Furthermore, the integration of spatial pattern analysis obtained from satellite images and aerial photographs with forest and regeneration characterization from field sampling allowed to identify the most vulnerable areas. The methodology presented here can assist in the identification of target areas for spatial conservation, including management needs under the current budget restrictions.

Keywords: Landscape Conservation, Landscape Metrics, Landscape Connectivity, Spatial Pattern Indicators

iForest 9 (2): 244-252 (2016) - doi: 10.3832/ifor1399-008
https://iforest.sisef.org/contents/?id=ifor1399-008

Research Articles: Effects of black locust and black pine on extremely degraded sites 60 years after afforestation - a case study of the Grdelica Gorge (southeastern Serbia)

Lukić S, Pantić D, Simić SB, Borota D, Tubić B, Djukić M, Djunisijević-Bojović D — 2015-08-22

Lukić S, Pantić D, Simić SB, Borota D, Tubić B, Djukić M, Djunisijević-Bojović D

EFFECTS OF BLACK LOCUST AND BLACK PINE ON EXTREMELY DEGRADED SITES 60 YEARS AFTER AFFORESTATION - A CASE STUDY OF THE GRDELICA GORGE (SOUTHEASTERN SERBIA)

Abstract: The selection of tree species can affect the success of afforestation in the rehabilitation of degraded forest sites and forest restoration. In general, black locust (Robinia pseudoacacia L.) and black pine (Pinus nigra Arnold.) represent the most commonly used species in the afforestation of soils that have been degraded by erosion. As far as the extent of the ameliorative effects of black locust and black pine are concerned, it was found that they may play an important role in the selection of species for the afforestation of extremely degraded sites. This study is aimed at determining the potential of black locust and black pine to affect several soil properties, erosion control and C stock, thus creating favourable site conditions for the restoration of previous forest vegetation. This research was conducted in the Grdelica Gorge in south east Serbia, where eight sample plots with an average size of 0.47 ha were established 60 years ago on terrain afforested with black locust and black pine. In each sample plot, we measured the diameter at breast height of all black locust and black pine trees, and the height of 10 black locust and 10 black pine trees in each diameter class. In addition, samples of mineral soil (from depths of 0-5, 5-10 and 10-20 cm) were taken at 4 randomly selected soil profiles in each sample plot, and 8 samples of litter (30 × 30 cm) were also collected. Additionally, laboratory analyses of the physical and chemical properties of the soil and litter were performed in 2 replicates. The obtained results showed that: (1) at the 0-5 cm depth, there was no statistically significant difference in the reaction of the soil solution, although a significant difference in the reaction of the soil solution between the soils under the two species was observed at soil depths greater than 5 cm; (2) there was a significantly higher N content under black locust in the 0-5 cm soil layer; (3) the reduction of soil loss under black locust is statistically significant in all observation periods; (4) black pine is more efficient in C storage. Our results demonstrate that black locust has the potential to improve soil properties and reduce soil loss caused by erosion, while its favourable impact does not decrease over time, making it more suitable for afforestation on degraded land in the examined area.

Keywords: Afforestation, Black Locust, Black Pine, Soil Properties, Soil Losses, Carbon Stock

iForest 9 (2): 235-243 (2016) - doi: 10.3832/ifor1512-008
https://iforest.sisef.org/contents/?id=ifor1512-008

Research Articles: Carbon storage in degraded cork oak (Quercus suber) forests on flat lowlands in Morocco

Oubrahim H, Boulmane M, Bakker MR, Augusto L, Halim M — 2015-08-08

Oubrahim H, Boulmane M, Bakker MR, Augusto L, Halim M

CARBON STORAGE IN DEGRADED CORK OAK (QUERCUS SUBER) FORESTS ON FLAT LOWLANDS IN MOROCCO

Abstract: The present study aims to quantify the carbon stored in a degraded cork oak (Quercus suber L.) ecosystem in the north west of Morocco, in view of potential management implications. To this end, carbon stocks were evaluated in the first 100 cm of the soil, the cork oak trees, and the understorey species (both above- and belowground). Results show that the total carbon stocks in the cork oak ecosystem ranges from 65 to 237 Mg ha-1 with a mean value of 121 Mg ha-1. The first 100 cm of the soil (including the forest floor) represents the largest carbon pool (~51% of the total organic carbon) of the ecosystem. Tree biomass (above- and belowground tissues of cork oak) represents the second largest pool (47%), whereas the contribution of the understorey is less than 2%. Within the first 100 cm of the soil, over 87% of all the soil organic carbon is situated in the first 40 cm of the soil depth. The amount of carbon stored here ranges from 30 to 110 Mg ha-1and these organic carbon stocks vary considerably with the stand basal area of the cork oak (R2 = 0.82). In practice, the carbon stocks of the different pools considered are strongly correlated with the stand density of the cork oak stands. In the semi-arid forest ecosystems of our study, management prescriptions aiming at increasing the standing biomass of the cork oak should thus considerably contribute, both directly through tree biomass and indirectly through increased soil organic matter, to efficient carbon sequestration.

Keywords: Quercus suber, Mamora, Carbon Storage, Biomass, Litter and Soil

iForest 9 (1): 125-137 (2016) - doi: 10.3832/ifor1364-008
https://iforest.sisef.org/contents/?id=ifor1364-008

Research Articles: Coupling daily transpiration modelling with forest management in a semiarid pine plantation

Fernandes TJ, Campo ADD, García-Bartual R, González-Sanchis M — 2015-08-06

Fernandes TJ, Campo ADD, García-Bartual R, González-Sanchis M

COUPLING DAILY TRANSPIRATION MODELLING WITH FOREST MANAGEMENT IN A SEMIARID PINE PLANTATION

Abstract: Estimating forest transpiration is of great importance for Adaptive Forest Management (AFM) in the scope of climate change prediction. AFM in the Mediterranean region usually generates a mosaic of different canopy covers within the same forest. Several models and methods are available to estimate forest transpiration, but most require a homogeneous forest cover, or an individual calibration/validation process for each cover stand. Hence, a model capable of reproducing accurately the transpiration of the whole canopy-cover mosaic is necessary. In this paper, the use of Artificial Neural Network (ANN) is proposed as a flexible tool for estimating forest transpiration using the forest cover as an input variable. To that end, sap flow, soil water content and other environmental variables were experimentally collected under five Aleppo pine stands of different canopy covers for two years. These sets of inputs were then used for the ANN training. Stand transpiration was accurately estimated using climate data, soil water content and forest cover through the ANN approach (correlation coefficient R = 0.95; Nash-Sutcliffe coefficient E = 0.90; root-mean-square error RMSE = 0.078 mm day-1). Finally, the input value for soil water content (when not available) was computed using the process-based model Gotilwa+. Then, this computed soil water content was used as input in the proposed ANN. This combination predicted the forest transpiration with values of R = 0.90, E = 0.63, and RMSE = 0.068 mm day-1. Artificial Neural Network proved to be a useful and flexible tool to predict the transpiration dynamics of an Aleppo pine stand regardless of the heterogeneity of the forest cover produced by adaptive forest management.

Keywords: Adaptive Forest Management, Artificial Neural Network (ANN), Forest Water-use, Pinus halepensis Mill.

iForest 9 (1): 38-48 (2016) - doi: 10.3832/ifor1290-008
https://iforest.sisef.org/contents/?id=ifor1290-008

Research Articles: Modeling extreme values for height distributions in Pinus pinaster, Pinus radiata and Eucalyptus globulus stands in northwestern Spain

Gorgoso-Varela JJ, García-Villabrille JD, Rojo-Alboreca A — 2015-07-25

Gorgoso-Varela JJ, García-Villabrille JD, Rojo-Alboreca A

MODELING EXTREME VALUES FOR HEIGHT DISTRIBUTIONS IN PINUS PINASTER, PINUS RADIATA AND EUCALYPTUS GLOBULUS STANDS IN NORTHWESTERN SPAIN

Abstract: Methods of estimating extreme height values can be used in forest modeling to improve fits to the marginal distribution of heights in the following bivariate diameter-height models: the SBB Johnson’s distribution, the bivariate beta (GDB-2) distribution, the bivariate Logit-Logistic (LL-2) distribution and the power-normal (PN) distribution. Some applications to LiDAR derived data are also possible, e.g., for error calibration. Practical applications in forest management may also be considered, e.g., for pruning. In probability theory and statistics, the generalized extreme value (GEV) distribution, also known as the Fisher-Tippett distribution, is a family of continuous probability distributions that combine the Gumbel, Fréchet and Weibull distributions. This study compared the three distributions for fitting extreme values of tree heights (maximum and minimum heights), which were measured in 185 permanent research plots in Pinus pinaster Ait. stands, 97 research plots in Pinus radiata D. Don stands, and 128 research plots in Eucalyptus globulus Labill. Most of the eucalyptus stands were measured three times giving a total of 304 measurements. All plots are located in northwestern Spain. The Bias, Mean Absolute Error (MAE) and Mean Square Error (MSE) of the mean relative frequency of trees were used to evaluate the goodness-of-fit of the different functions, as well as the Kolmogorov-Smirnov statistic Dn. The Gumbel and the Weibull cumulative distribution functions (CDFs) proved suitable for describing extreme values of height distributions of the above-mentioned tree species in northwestern Spain. The Fréchet distribution was only used to model maximum values and yielded the poorest results in all cases.

Keywords: Gumbel, Fréchet, Weibull, Minimum Height, Maximum Height

iForest 9 (1): 23-29 (2016) - doi: 10.3832/ifor1447-008
https://iforest.sisef.org/contents/?id=ifor1447-008

Research Articles: Spatially explicit estimation of forest age by integrating remotely sensed data and inverse yield modeling techniques

2015-07-25

Frate L, Carranza ML, Garfì V, Febbraro MD, Tonti D, Marchetti M, Ottaviano M, Santopuoli G, Chirici G

SPATIALLY EXPLICIT ESTIMATION OF FOREST AGE BY INTEGRATING REMOTELY SENSED DATA AND INVERSE YIELD MODELING TECHNIQUES

Abstract: In this work we present an innovative method based on the application of inverse yield models for producing spatially explicit estimations of forest age. Firstly, a raster growing stock volume map was produced using the non-parametric k-Nearest Neighbors estimation method on the basis of IRS LISS-III remotely sensed imagery and field data collected in the framework of a local forest inventory. Secondly, species specific inverted yield equations were applied to estimate forest age as a function of growing stock volume. The method was tested in 128.000 ha of even-aged forests in central Italy (Molise region). The accuracy of the method was assessed using an independent dataset of 305 units from a local standwise forest inventory. The results demonstrated that the forest age map was accurate, with a root mean square error of 15.8 years (30% of the mean of field values), thus at least useful for supporting forest management purposes, such as the assessment of harvesting potential, and of ecosystem services. Thanks to the use of remotely sensed data and spatial modeling, the approach we propose is cost-effective and easily replicable for vast regions.

Keywords: k-Nearest Neighbors, Mapping, Forest Inventory, Growing Stock, IRS LISS-III

iForest 9 (1): 63-71 (2016) - doi: 10.3832/ifor1529-008
https://iforest.sisef.org/contents/?id=ifor1529-008

Research Articles: Chloroplast microsatellites as a tool for phylogeographic studies: the case of white oaks in Poland

Chmielewski M, Meyza K, Chybicki IJ, Dzialuk A, Litkowiec M, Burczyk J — 2015-07-19

Chmielewski M, Meyza K, Chybicki IJ, Dzialuk A, Litkowiec M, Burczyk J

CHLOROPLAST MICROSATELLITES AS A TOOL FOR PHYLOGEOGRAPHIC STUDIES: THE CASE OF WHITE OAKS IN POLAND

Abstract: Assessing the distribution of chloroplast DNA (cpDNA) haplotype variation is useful for studying the phylogeography of angiosperms. In the last two decades the cpDNA phylogeography of white oaks in Europe has been extensively studied, mostly based on the PCR-RFLP technique. However, PCR-RFLPs have low mutation rates and are primarily useful for reconstructing patterns at large geographical scales and lack resolution at fine spatial scales. Here we evaluate the usefulness of chloroplast microsatellites (cpSSR) as an alternative to PCR-RFLPs in Polish oak populations which have been underrepresented in previous studies. Eighty-five cpSSR haplotypes were detected using 14 cpSSR loci and a broad collection of 6680 trees sampled throughout Poland. Haplotype diversity was significantly lower in Q. petraea (He = 0.798) than in Q. robur (He = 0.820). Only 17 haplotypes (H01-H17) were found in 13 or more individuals, comprising together 97.9% of the sample. Most frequent cpSSR haplotypes were related to PCR-RFLP haplotypes, establishing the cross-references between the two marker systems. There was significant concordance between the matrices of genetic distances obtained by PCR-RFLP haplotypes and cpSSR haplotypes. Phylogenetic relationships among cpSSR haplotypes supported the existence of the three predominant maternal lineages of oaks in Poland: Iberian (7.8%), Apennine (20.6%) and Balkan (65.5%). The results are discussed with regards to the usefulness of cpSSR markers for phylogeographic studies.

Keywords: Chloroplast Microsatellites, PCR-RFLP, White Oaks, Phylogeography

iForest 8 (6): 765-771 (2015) - doi: 10.3832/ifor1597-008
https://iforest.sisef.org/contents/?id=ifor1597-008

Research Articles: Effects of drought and nutrient deficiency on grafts originating from sound and shaken sweet chestnut trees (Castanea sativa Mill.)

Mutabaruka C, Cook HF, Buckley GP — 2015-07-19

Mutabaruka C, Cook HF, Buckley GP

EFFECTS OF DROUGHT AND NUTRIENT DEFICIENCY ON GRAFTS ORIGINATING FROM SOUND AND SHAKEN SWEET CHESTNUT TREES (CASTANEA SATIVA MILL.)

Abstract: Scions taken from felled, shaken or sound sweet chestnut trees (Castanea sativa Mill.) were grafted and grown for one year in a polythene tunnel in order to compare their responses to water and nutrient stresses. Phenological characteristics of the original trees were strongly reproduced in the grafts grown both in this controlled environment and later on in the field. Grafts originating from shaken trees flushed up to six days later, senesced earlier and produced larger spring vessels. Artificially imposed drought reduced stomatal densities by 5.6% and xylem vessel diameters by up to 35%. Fertiliser additions significantly increased stem increments and promoted earlier flowering, with hermaphrodite flowering filaments more common in grafts from shaken trees. It is considered that, because of their larger spring vessels, shaken trees may be more vulnerable to cavitation and therefore to drought, even though moisture stress is mitigated by some plasticity in earlywood vessel diameter.

Keywords: Shake Defect, Castanea Sativa, Moisture Stress, Soil Fertility

iForest 9 (1): 109-114 (2016) - doi: 10.3832/ifor1572-008
https://iforest.sisef.org/contents/?id=ifor1572-008

Research Articles: Analysis of factors influencing deployment of fire suppression resources in Spain using artificial neural networks

Costafreda-Aumedes S, Cardil A, Molina DM, Daniel SN, Mavsar R, Vega-Garcia C — 2015-07-19

Costafreda-Aumedes S, Cardil A, Molina DM, Daniel SN, Mavsar R, Vega-Garcia C

ANALYSIS OF FACTORS INFLUENCING DEPLOYMENT OF FIRE SUPPRESSION RESOURCES IN SPAIN USING ARTIFICIAL NEURAL NETWORKS

Abstract: In Spain, the established fire control policy states that all fires must be controlled and put out as soon as possible. Though budgets have not restricted operations until recently, we still experience large fires and we often face multiple-fire situations. Furthermore, fire conditions are expected to worsen in the future and budgets are expected to drop. To optimize the deployment of firefighting resources, we must gain insights into the factors affecting how it is conducted. We analyzed the national data base of historical fire records in Spain for patterns of deployment of fire suppression resources for large fires. We used artificial neural networks to model the relationships between the daily fire load, fire duration, fire type, fire size and response time, and the personnel and terrestrial and aerial units deployed for each fire in the period 1998-2008. Most of the models highlighted the positive correlation of burned area and fire duration with the number of resources assigned to each fire and some highlighted the negative influence of daily fire load. We found evidence suggesting that firefighting resources in Spain may already be under duress in their compliance with Spain’s current full suppression policy.

Keywords: Fire Management, Neural Networks, Regional Models, Suppression Resources, Wildfire

iForest 9 (1): 138-145 (2016) - doi: 10.3832/ifor1329-008
https://iforest.sisef.org/contents/?id=ifor1329-008

Research Articles: Effects of artificial defoliation and simulated insect damage on the growth of Betula pendula saplings

Varnagiryte-Kabašinskiene I, Araminiene V, Stakenas V — 2015-07-15

Varnagiryte-Kabašinskiene I, Araminiene V, Stakenas V

EFFECTS OF ARTIFICIAL DEFOLIATION AND SIMULATED INSECT DAMAGE ON THE GROWTH OF BETULA PENDULA SAPLINGS

Abstract: One-year-old silver birch (Betula pendula Roth) saplings were subjected to artificial insect damage and defoliations of varying intensities, and subsequent growth indexes, biomass allocation patterns and photosynthesis were monitored during a 60-day period. Seven treatments were conducted in which the leaves of saplings were perforated with three or six holes per each leaf, and damaged by clipping one-third of each leaf, or they received 25, 50 and 75% defoliations during a single growing season (from April to August of 2014). Simulated insect damage and artificial defoliation decreased growth. The 75% defoliation significantly reduced the total dry mass of birch saplings at harvest by 30%, while such reduction did not influence the total productivity. The dry mass of leaves was reduced by 45% when saplings were defoliated by 75% compared to not defoliated saplings. Moreover, the total production of leaves significantly increased in the 75% defoliated saplings compared with control saplings. Artificial defoliation increased the relative biomass allocation to foliage, and this was more evident in defoliated than in mechanically insect-damaged saplings. Despite losing 25, 50 or 75% of leaf mass due to clipping, defoliated birch saplings recovered similar dry masses and root/shoot ratios by harvest as the non-defoliated saplings. Perforation and clipping parts of the leaves, as well as the artificial defoliations, caused the regrowth of biomass that did not significantly change compared to healthy silver birch saplings, and this phenomenon could be assessed as equal-compensatory growth.

Keywords: Betula pendula, Artificial Defoliation, Artificial Insect-Damage, Growth Compensation

iForest 9 (1): 95-100 (2016) - doi: 10.3832/ifor1522-008
https://iforest.sisef.org/contents/?id=ifor1522-008

Research Articles: Chemometric technique performances in predicting forest soil chemical and biological properties from UV-Vis-NIR reflectance spectra with small, high dimensional datasets

Bellino A, Colombo C, Iovieno P, Alfani A, Palumbo G, Baldantoni D — 2015-07-15

Bellino A, Colombo C, Iovieno P, Alfani A, Palumbo G, Baldantoni D

CHEMOMETRIC TECHNIQUE PERFORMANCES IN PREDICTING FOREST SOIL CHEMICAL AND BIOLOGICAL PROPERTIES FROM UV-VIS-NIR REFLECTANCE SPECTRA WITH SMALL, HIGH DIMENSIONAL DATASETS

Abstract: Chemometric analysis applied to diffuse reflectance spectroscopy is increasingly proposed as an effective and accurate methodology to predict soil physical, chemical and biological properties. Its effectiveness, however, largely varies in relation to the calibration techniques and the specific soil properties. In addition, the calibration of UV-Vis-NIR spectra usually requires large datasets, and the identification of techniques suitable to deal with small sample sizes and high dimensionality problems is a primary challenge. In order to investigate the predictability of many soil chemical and biological properties from a small dataset and to identify the most suitable techniques to deal with this type of problems, we analysed 20 top soil samples of three different forests (Fagus sylvatica, Quercus cerris and Quercus ilex) in southern Apennines (Italy). Diffuse reflectance spectra were recorded in the UV-Vis-NIR range (200-2500 nm) and 22 chemical and biological properties were analysed. Three different calibration techniques were tested, namely the Partial Least Square Regression (PLSR), the combinations wavelet transformation/Elastic net and wavelet transformation/Supervised Principal Component (SPC) regression/ Least Absolute Shrinkage and Selection Operator (LASSO), a kind of preconditioned LASSO. Calibration techniques were applied to both raw spectra and spectra subjected to wavelet shrinkage filtering, in order to evaluate the influence on predictions of spectra denoising. Overall, SPC/LASSO outperformed the other techniques with both raw and denoised spectra. Elastic net produced heterogeneous results, but outperformed SPC/LASSO for total organic carbon, whereas PLSR produced the worst results. Spectra denoising improved the prediction accuracy of many parameters, but worsen the predictions in some cases. Our approach highlighted that: (i) SPC/LASSO (and Elastic net in the case of total organic carbon) is especially suitable to calibrate spectra in the case of small, high dimensional datasets; and (ii) spectra denoising could be an effective technique to improve calibration results.

Keywords: Elastic Net, PLSR, SPC/LASSO, Wavelets, Diffuse Reflectance Spectroscopy, Sample Size

iForest 9 (1): 101-108 (2016) - doi: 10.3832/ifor1495-008
https://iforest.sisef.org/contents/?id=ifor1495-008

Review Papers: Sweetgum: a new look

Adams JP, Lingbeck JM, Crandall PG, Martin EM, O’Bryan CA — 2015-06-23

Adams JP, Lingbeck JM, Crandall PG, Martin EM, O’Bryan CA

SWEETGUM: A NEW LOOK

Abstract: Sweetgum (Liquidambar styraciflua L.) is the only species of its genus in the Western hemisphere. The species is a relatively early successional species with wide seed dispersal, fast growth and is considered one of the most adaptable tree species in North America, growing across a wide range of soil types, altitudes, and hydrologic conditions. This species has routinely been considered a lesser desired species by many forest managers trying to grow tree plantations or even in natural stands because the species tends to rapidly invade and dominate a site. However, because of sweetgum’s adaptability, ease of propagation and field planting, and fast growth rate, the tending of sweetgum as a potential crop for improved markets has been reinvigorated. Managing sweetgum also opens the possibility of development of new products and markets that supplement the traditional markets and can produce further value-added products. Increasingly, sweetgum is not viewed with as much antipathy amongst foresters and its potential as valuable resources is being rediscovered.

Keywords: Sweetgum, Liquidambar styraciflua L., Fast-growing species, Potential crop, Value-added products

iForest 8 (6): 719-727 (2015) - doi: 10.3832/ifor1462-008
https://iforest.sisef.org/contents/?id=ifor1462-008

Research Articles: Developing a stand-based growth and yield model for Thuya (Tetraclinis articulata (Vahl) Mast) in Tunisia

Sghaier T, Sánchez-González M, Garchi S, Ammari Y, Cañellas I, Calama R — 2015-06-23

Sghaier T, Sánchez-González M, Garchi S, Ammari Y, Cañellas I, Calama R

DEVELOPING A STAND-BASED GROWTH AND YIELD MODEL FOR THUYA (TETRACLINIS ARTICULATA (VAHL) MAST) IN TUNISIA

Abstract: Thuya (Tetraclinis articulata (Vahl) Mast) is a Mediterranean forest species mainly occupying semiarid environments in North African countries, where it provides important ecological and economical services, such as biodiversity conservation, soil protection against erosion, fuelwood, timber for fencing, construction and handicraft, resins, etc. Despite the importance of the species, there is a severe lack of scientific knowledge as regards the management of these forests or modeling tools to support multifunctional forest management decision making. In the present work, we developed a stand-level integrated model for the management of Thuya forests in Tunisia. The model comprises a family of site index curves, built using the Generalized Algebraic Difference Approach (GADA) method, which provides predictions for stand growth, aboveground biomass, total and merchantable volumes, along with a non-linear system of stand level equations presented as stand density management diagrams (SDMD). The developed model has been used to define, characterize and compare four different management specific schedules for different site qualities and multifunctional objectives.

Keywords: Site Index Model, Stand Density Management Diagram, Semiarid Environments, Stand-level Model, Management Schedule, Thinning

iForest 9 (1): 79-88 (2016) - doi: 10.3832/ifor1389-008
https://iforest.sisef.org/contents/?id=ifor1389-008

Research Articles: Spatial and temporal variation of drought impact on black locust (Robinia pseudoacacia L.) water status and growth

Mantovani D, Veste M, Böhm C, Vignudelli M, Freese D — 2015-06-18

Mantovani D, Veste M, Böhm C, Vignudelli M, Freese D

SPATIAL AND TEMPORAL VARIATION OF DROUGHT IMPACT ON BLACK LOCUST (ROBINIA PSEUDOACACIA L.) WATER STATUS AND GROWTH

Abstract: Stimulated by the rising demand for bioenergy, forestry practices for energy production are of increasing importance worldwide. Black locust (Robinia pseudoacacia L.) is a suitable tree species for biomass production in short-rotation plantations in East Germany, especially on marginal land where insufficient water and nutrients are a limiting factor for tree growth. Our study aims to clarify the spatial and temporal variability of the black locust growth through the analysis of the plant water status, and to evaluate the effect of adverse edaphic conditions on growth performances, amplified by periods of summer drought. The study was carried out at two sites presenting comparable climatic but different edaphic conditions: (i) fertile agricultural soil; and (ii) heterogeneous unstructured soil from a reclaimed post-mining area. During the vegetation period, the growth rate decreased in both sites following the plant water status in terms of pre-dawn leaf water potential. Particularly in the post-mining area, due to the adverse edaphic conditions, below the critical pre-dawn water potential value of -0.5 MPa, the stem growth was drastically reduced during a period of summer drought. However, the trees could cope with the extreme soil and weather conditions in the post-mining site without perishing.

Keywords: Agroforestry, Drought Stress, Soil Water Availability, Soil Heterogeneity, Reclamation

iForest 8 (6): 743-747 (2015) - doi: 10.3832/ifor1299-008
https://iforest.sisef.org/contents/?id=ifor1299-008

Research Articles: Latent infection of Biscogniauxia nummularia in Fagus sylvatica: a possible bioindicator of beech health conditions

Luchi N, Capretti P, Feducci M, Vannini A, Ceccarelli B, Vettraino AM — 2015-06-18

Luchi N, Capretti P, Feducci M, Vannini A, Ceccarelli B, Vettraino AM

LATENT INFECTION OF BISCOGNIAUXIA NUMMULARIA IN FAGUS SYLVATICA: A POSSIBLE BIOINDICATOR OF BEECH HEALTH CONDITIONS

Abstract: Biscogniauxia nummularia is a xylariaceous fungus known as a common endophyte of European beech, living in plant tissues without development of symptoms, or even inducing strip-cankers and wood decay on trees stressed by drought. We studied the presence of the fungus in apparently healthy beech trees, growing in two different bioclimatic zones characterized by Continental and Mediterranean climates. Asymptomatic twigs were collected in each zone over the season and evaluated for the presence of B. nummularia infections using both cultural and qPCR methods. Results from qPCR indicated differences in the detection of B. nummularia among the seasons and between the study sites. In both sites the highest frequency of detection was in summer. B. nummularia was more frequently detected in the Mediterranean bioclimatic area, where drought is more common. These results suggest that B. nummularia may be a possible bioindicator of beech health stands.

Keywords: Fagus sylvatica, Latent Pathogen, Real Time PCR, Xylariaceae

iForest 9 (1): 49-54 (2016) - doi: 10.3832/ifor1436-008
https://iforest.sisef.org/contents/?id=ifor1436-008

Research Articles: Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates in northwestern Turkey

Sariyildiz T, Savaci G, Kravkaz IS — 2015-06-18

Sariyildiz T, Savaci G, Kravkaz IS

EFFECTS OF TREE SPECIES, STAND AGE AND LAND-USE CHANGE ON SOIL CARBON AND NITROGEN STOCK RATES IN NORTHWESTERN TURKEY

Abstract: Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates were investigated in the northwest of Turkey using 4 common tree species as black pine (Pinus nigra Arnold.), Scots pine (Pinus sylvestris L.), Oriental beech (Fagus orientalis Lipsky) and Uludag fir (Abies nordmanniana ssp. bornmuelleriana). Three tree species (black pine, Scots pine and Oriental beech) were used to investigate the differences in soil C and N among tree species. Old and young Uludag fir stands and adjacent grassland were used to study the differences in soil C and N with stand age and land-use change. Mineral soil samples were taken from 0-10 cm and 10-20 cm soil depths, and analyzed for pH, soil texture, bulk density, total soil carbon and total nitrogen. The total soil carbon and total nitrogen pools were then calculated by multiplying soil volume, soil bulk density, and the total soil carbon or total nitrogen content. Results showed significant differences in soil carbon and nitrogen contents, carbon/nitrogen ratios and stock rates among the three species, and between old and young fir stands and grassland. In general, when 0-20 cm soil depth was considered, mean soil carbon stock rate was the highest under black pine (79 Mg C ha-1) followed by Scots pine (73 Mg C ha-1) and beech (67 Mg C ha-1), whereas mean soil nitrogen stock rate was the highest under beech (9.57 Mg N ha-1) followed by Scots pine (5.77 Mg N ha-1) and black pine (4.20 Mg N ha-1). Young fir stands showed lower soil carbon stock, but higher soil nitrogen stock rates compared to old fir stands and grassland. Our results demonstrated that tree species, stand tree age and land-use change can have significant effects on soil carbon and nitrogen content and stocks rates. These findings can help to enhance forest management activities, such as selection of tree species for carbon sequestration in plantation systems, design of sustainable agroforestry systems, and improvement of biogeochemical models.

Keywords: Forest Soil, Climate Change, Soil Carbon and Nitrogen Budget, Grassland, Turkey

iForest 9 (1): 165-170 (2016) - doi: 10.3832/ifor1567-008
https://iforest.sisef.org/contents/?id=ifor1567-008

Research Articles: Relationship between tree growth and physical dimensions of Fagus sylvatica crowns assessed from terrestrial laser scanning

Seidel D, Schall P, Gille M, Ammer C — 2015-06-11

Seidel D, Schall P, Gille M, Ammer C

RELATIONSHIP BETWEEN TREE GROWTH AND PHYSICAL DIMENSIONS OF FAGUS SYLVATICA CROWNS ASSESSED FROM TERRESTRIAL LASER SCANNING

Abstract: Measurements of physical tree crown dimensions were of subjective character in the past, even though they can be considered important for the management of many silvicultural operations, such as timing of thinning operations. In our study we investigated if and how measures of physical crown dimensions of trees differed when quantified conventionally versus based on 3D-terrestrial laser scanning and how they are related to basal area increment. Some 24 randomly selected predominant or dominant beech trees between 90 and 110 yrs of age and of varying height were used as study trees. We hypothesized that tree crown dimensions obtained from scans are more closely related to tree radial growth than those obtained from conventional field measurements. It was found that from a variety of compared crown size characteristics the scan-based tree attributes mean crown radius, maximum area of the crown and crown projection area were most closely related to individual tree growth. We conclude that the horizontal extension of a tree crown in general is to be considered one of the most important drivers of tree growth. We also conclude that terrestrial laser scanning is a powerful tool to reliably measure physical crown dimensions and TLS-based measurements are more reliable than conventional ones.

Keywords: Tree Geometry, Crown Structure, Crown Surface Area, Basal Area Increment

iForest 8 (6): 735-742 (2015) - doi: 10.3832/ifor1566-008
https://iforest.sisef.org/contents/?id=ifor1566-008

Research Articles: Evaluation and correction of optically derived leaf area index in different temperate forests

Liu Z, Jin G, Zhou M — 2015-06-11

Liu Z, Jin G, Zhou M

EVALUATION AND CORRECTION OF OPTICALLY DERIVED LEAF AREA INDEX IN DIFFERENT TEMPERATE FORESTS

Abstract: In recent years optical techniques for rapid LAI measurements have been developed, but few studies have been performed to evaluate the accuracy of optical estimation of LAI in mixed deciduous-evergreen forest stands. In this paper, we assessed the accuracy of digital hemispherical photography (DHP) and the LAI-2000 for the estimation of effective LAI (Le) by comparison with litter collection LAI (LAIlit) in four mixed deciduous broadleaf and evergreen needleleaf forests and one deciduous needleleaf forest. We also evaluated the relative contribution of major error sources to the determination of LAI by optical methods, including the woody-to-total area ratio (α), the element clumping index (ΩE) and the needle-to-shoot area ratio (γE). Additionally, incorrect automatic photographic exposure has been considered for DHP. DHP Le underestimated LAIlit by an average of 44-70% in different forests, and the difference between LAIlit and DHP Le after correction for the automatic exposure, α, ΩE and γE ranged from 1% to 21% in five forest stands. In contrast, LAI values from LAI-2000 were more similar to the direct litter collection LAI. The LAI-2000 Le underestimated LAIlit by an average of 13-40% in these forests, while the accuracy of the best estimates of LAI using LAI-2000 methods is over 93% after considering α, ΩE and γE. The error caused by automatic exposure to DHP Le is larger than other factors in all forest stands, and the γE was the main uncertainty to LAI-2000 Le in most forest stands. Moreover, optical LAI (both DHP and LAI-2000) was significantly (P < 0.01) correlated with LAIlit, especially the corrected LAI obtained by the LAI-2000 (R2 = 0.83, RMSE = 1.04). Our results demonstrate that the above factors affect the estimation of LAI by optical methods, thus the species composition of a forest stand should be seriously considered in order to improve the accuracy of LAI by optical methods.

Keywords: Leaf Area Index (LAI), Digital Hemispherical Photography (DHP), LAI-2000, Woody Materials, Clumping Effects, Automatic Exposure, Litter Collection, Correlation

iForest 9 (1): 55-62 (2016) - doi: 10.3832/ifor1350-008
https://iforest.sisef.org/contents/?id=ifor1350-008

Research Articles: Height-diameter models for maritime pine in Portugal: a comparison of basic, generalized and mixed-effects models

2015-06-11

Gómez-García E, Fonseca TF, Crecente-Campo F, Almeida LR, Diéguez-Aranda U, Huang S, Marques CP

HEIGHT-DIAMETER MODELS FOR MARITIME PINE IN PORTUGAL: A COMPARISON OF BASIC, GENERALIZED AND MIXED-EFFECTS MODELS

Abstract: Tree height is a key variable in forest monitoring studies and for forest management. However, tree height measurement is time consuming, and the recommended procedure is to use estimates from height-diameter models. Here, we compare height-diameter model forms and approaches for predicting tree height (h) as a function of tree diameter at breast height (d) and additional stand level covariates. Four model forms were evaluated: (i) basic models (which only used d as predictor variable); (ii) generalized models (which used d and stand-level predictor variables); (iii) a mixed-effects model based on the best basic model; and (iv) a mixed-effects model based on the best generalized model. Several alternatives aimed at minimizing height measurement effort were tested in terms of accuracy and applicability. From a practical point of view, the selected generalized model is recommended for estimating the height of maritime pine in Portugal. The results also show that a calibrated basic mixed model provides more accurate results than a basic model locally fitted when the number of h-d observations is limited.

Keywords: Pinus pinaster Ait., Sampling Design, Local Model, Stand Variables, Generalized h-d Relationship, Calibration

iForest 9 (1): 72-78 (2016) - doi: 10.3832/ifor1520-008
https://iforest.sisef.org/contents/?id=ifor1520-008

Research Articles: Optimum light transmittance for seed germination and early seedling recruitment of Pinus koraiensis: implications for natural regeneration

Zhang M, Yan Q, Zhu J — 2015-05-22

Zhang M, Yan Q, Zhu J

OPTIMUM LIGHT TRANSMITTANCE FOR SEED GERMINATION AND EARLY SEEDLING RECRUITMENT OF PINUS KORAIENSIS: IMPLICATIONS FOR NATURAL REGENERATION

Abstract: Light transmittance regulated by canopy openness influences the microsite conditions for natural regeneration. The successful transition from seed germination to subsequent seedling recruitment (i.e., early seedling survival and growth) determines the natural regeneration potential. However, there is little information on the effect of varying light transmittance on seed germination and seedling recruitment of Pinus koraiensis Siebold & Zucc. (Korean pine). We aimed to determine the optimum light requirements for this transition process in P. koraiensis to propose practical measures for improving its natural regeneration. The transition process was studied under five light transmittance regimes (100%, 60%, 30%, 15% and 5% of full light) over two consecutive years (2010 and 2011). The highest germination percentage in both years occurred at 30% light transmittance. Generally, mean germination time (MGT) declined with increased light transmittance. Seedling survival exhibited no significant differences between treatments for 1-year-old seedlings, but was higher at 30% than at 5% light transmittance for the 2-year-old seedlings. In contrast, seedling height, root collar diameter and total biomass were highest at 60%-100% light transmittance for both 1- and 2-year-old seedlings. Furthermore, the light transmittance also influenced the growth characteristics of P. koraiensis seedlings through regulating MGT. These results suggest that growth of P. koraiensis seedling requires a higher light transmittance (60%-100%) than that required for seed germination, even though 30% light transmittance was favorable to the earlier emergence with larger specific leaf area. Silvicultural measures such as thinning are recommended to increase light irradiance in the forest understorey with the aim of improving the natural regeneration of P. koraiensis.

Keywords: Germination, Light Transmittance, Natural Regeneration, Seedling Emergence, Seedling Survival

iForest 8 (6): 853-859 (2015) - doi: 10.3832/ifor1397-008
https://iforest.sisef.org/contents/?id=ifor1397-008

Research Articles: Physical and mechanical characteristics of poor-quality wood after heat treatment

Romagnoli M, Cavalli D, Pernarella R, Zanuttini R, Togni M — 2015-05-22

Romagnoli M, Cavalli D, Pernarella R, Zanuttini R, Togni M

PHYSICAL AND MECHANICAL CHARACTERISTICS OF POOR-QUALITY WOOD AFTER HEAT TREATMENT

Abstract: Poor-quality Corsican pine (Pinus nigra subsp. laricio (Poir.) Maire) and Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) wood samples were heat treated to improve wood quality and subsequent economic value. Wood properties were measured to assess quality in treated and non-treated materials, including density, hardness, anti-swelling efficiency (ASE), modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength. The results showed higher dimensional stability in heat-treated wood, yet mechanical performance in compression and bending strength were only marginally affected by loss of density. Despite having a relatively low density , Corsican pine sapwood has potential in manufacturing higher-value products. In contrast, heat treatment applied to Douglas fir wood did not appear economically viable; insufficient differences were detected between the naturally desirable characteristics of this species and heat-treated samples.

Keywords: Thermowood, Density, Compressive Strength, Bending Strength, Sapwood, Wood Quality, Douglas Fir, Corsican Pine

iForest 8 (6): 884-891 (2015) - doi: 10.3832/ifor1229-007
https://iforest.sisef.org/contents/?id=ifor1229-007

Research Articles: Impact of wheeled and tracked tractors on soil physical properties in a mixed conifer stand

Cambi M, Certini G, Fabiano F, Foderi C, Laschi A, Picchio R — 2015-05-22

Cambi M, Certini G, Fabiano F, Foderi C, Laschi A, Picchio R

IMPACT OF WHEELED AND TRACKED TRACTORS ON SOIL PHYSICAL PROPERTIES IN A MIXED CONIFER STAND

Abstract: Damage to forest soil caused by vehicle traffic mainly consists of soil compaction, displacement, and rut formation. Severity of the damage depends on vehicle mass, weight of the carried loads, ground morphology, and soil properties, such as moisture. This paper investigates the impacts of two types of vehicles (tracked or wheeled tractor), traffic intensities (one or five skidding cycles) and soil moisture (24% or 13% by weight) on compaction of a loam textured soil in a mixed conifer stand of central Italy. Changes in porosity, bulk density, shear and penetration resistances were analyzed. The latter three parameters were significantly higher in the trafficked soil portions than in the undisturbed ones in all treatments, while the opposite was true for porosity. The impact on soil bulk density and porosity was stronger for the wheeled tractor working on moist soil, while no significant effect of soil moisture was recorded for the tracked tractor. Shear and penetration resistances increased as a consequence of traffic, depending on both tractor type and soil moisture. The largest impact on shear resistance was recorded for the wheeled tractor on moist soil, while significant differences in penetration resistance were observed only between tracked and wheeled tractors in dry soil conditions. In order to preserve soil quality during logging activities, we recommend to operate under dry soil conditions and to limit vehicle movement on existing or new planned trails.

Keywords: Soil Compaction, Rutting, Skid Trails, Soil Degradation, Forest Management

iForest 9 (1): 89-94 (2016) - doi: 10.3832/ifor1382-008
https://iforest.sisef.org/contents/?id=ifor1382-008

Research Articles: Characterization of two poplar homologs of the GRAS/SCL gene, which encodes a transcription factor putatively associated with salt tolerance

Galovic V, Orlovic S, Fladung M — 2015-05-19

Galovic V, Orlovic S, Fladung M

CHARACTERIZATION OF TWO POPLAR HOMOLOGS OF THE GRAS/SCL GENE, WHICH ENCODES A TRANSCRIPTION FACTOR PUTATIVELY ASSOCIATED WITH SALT TOLERANCE

Abstract: To cope with soil salinity, which is one of the most severe forms of abiotic stress, efforts are being undertaken to enhance the salt tolerance of economically important poplar clones in the Vojvodina region of Serbia. One approach is to screen nucleotide diversity in candidate genes (CG) in several poplar clones of high economic importance to Serbia to search for associations with salt stress tolerance. As plant-specific GRAS/SCL transcription factors (TFs) play diverse roles in abiotic stress resistance, two poplar homologs of GRAS/SCL TFs were chosen to differentiate the species background with respect to salt tolerance. A BLAST search of the Populus trichocarpa genome using the P. euphratica gene GRAS/SCL TF_GH611858 sequence identified two putative orthologs, Scaf_5 and Scaf_7, with identities of 100% and 94%, respectively. Primers were designed in identical sequences of Scaf_5 and Scaf_7 to amplify fragments of GRAS/SCL TF orthologs in four poplar clones that are economically important to Serbia. The primers spanned regions where, at least in P. trichocarpa, single nucleotide polymorphisms (SNPs) are present, thereby increasing the probability of distinguishing Scaf_5 and Scaf_7 orthologs in the four clones. Alignments and analyses of the gene fragments revealed that both orthologs were representative of the genetic diversity between different poplar clones, and the identified SNP markers differentiated the four poplar clones with respect to salt tolerance.

Keywords: Candidate Gene, Nucleotide Polymorphism, Tree Genomics, Poplar

iForest 8 (6): 780-785 (2015) - doi: 10.3832/ifor1330-008
https://iforest.sisef.org/contents/?id=ifor1330-008

Research Articles: Bud flush phenology and nursery carryover effect of paper birch provenances

Dhar A, Balliet N, Hawkins CD, Carlson MR, Berger VG, Mahoney R — 2015-05-19

Dhar A, Balliet N, Hawkins CD, Carlson MR, Berger VG, Mahoney R

BUD FLUSH PHENOLOGY AND NURSERY CARRYOVER EFFECT OF PAPER BIRCH PROVENANCES

Abstract: Paper birch (Betula papyrifera Marsh) is an ecologically valuable species with a broad geographic distribution across the North America. Its diversity, versatility and enduring nature make it an ideal candidate for a selective breeding program in this region. However, an understanding of the genecology of this species is fundamental to deploy it successfully. Ten paper birch provenances were collected from British Columbia (BC, Canada) and northern Idaho (USA) along elevational transects to determine whether observed bud flush phenology was due to genetics and /or environmental variation or their interaction. Seedlings were grown at three different nurseries: University of Idaho (46°44’N), Landing (50°17’N) and Little Forestry (54°00’N) and planted in a randomized single tree interlocking block design in three common gardens at Sandpoint, ID (48°13’N), Skimikin, BC (50°45’N) and Red Rock, BC (53°45’N). Results indicate that variation in the timing of bud flush is a complex interaction among local genetic characteristics and environmental conditions of the growing site. Birch bud flush followed a general geographic trend where provenances at the southern common garden (Sandpoint) required less time (Day of Year, DoY) and fewer growing degree days (GDD) compared to central (Skimikin) and northern (Red Rock) common gardens. Although there were significant differences in the timing of bud flush among provenances along an elevational gradient, none of the regions showed the expected linear elevational cline, trends were inconsistent. Further, birch bud flush was significantly influenced by nursery displacement effects in the initial year of establishment but disappeared within three years. These results provide an opportunity to characterize bud flush phenology of paper birch and would be useful for improving operational paper birch seed transfer programs in BC.

Keywords: Betula papyrifera, Common Garden, Elevational Cline, Growing Degree Day (GDD), Day Of Year (DoY), Nursery Carry Over Effect, Provenance Trial, Seed-transfer

iForest 8 (6): 809-817 (2015) - doi: 10.3832/ifor1367-008
https://iforest.sisef.org/contents/?id=ifor1367-008

Technical Reports: Effects of different mechanical treatments on Quercus variabilis, Q. wutaishanica and Q. robur acorn germination

Liu Y, Hou L, Li Q — 2015-05-05

Liu Y, Hou L, Li Q

EFFECTS OF DIFFERENT MECHANICAL TREATMENTS ON QUERCUS VARIABILIS, Q. WUTAISHANICA AND Q. ROBUR ACORN GERMINATION

Abstract: Delayed and uneven germination of acorns has a negative effect on seedling quality and yield in seedlings. To address this issue, the effects of different mechanical treatments were studied, including a control (CK), removal of cup scar (RS), removal of pericarp (RP), removal of pericarp and 1/2 of the cotyledon (HC) and removal of pericarp and 2/3 cotyledon (TC), on the germination of Quercus variabilis, Q. wutaishanica and Q. robur acorns and pericarp thickness. The results showed that (1) RP and HC treatments significantly decreased root and shoot mean germination time, increased rooting and shooting germination percentage, and improved the root and shoot synchronization and vigor indexes of the three species’ acorns; (2) the acorns from the TC treatment significantly reduced root and shoot mean germination time and significantly induced the root and shoot synchronization index for all three species; and (3) the RS treatment significantly reduced the root and shoot mean germination time of the three species. Therefore, RP and HC treatments can effectively accelerate germination and regular seedling, which are important in the propagation of Q. variabilis, Q. wutaishanica and Q. robur seedlings. Even and quick germination help reduce acorn predation.

Keywords: Pericarp and Cotyledon Excision, Pericarp Thickness, Acorn Germination, Quercus wutaishanica

iForest 8 (6): 728-734 (2015) - doi: 10.3832/ifor1423-008
https://iforest.sisef.org/contents/?id=ifor1423-008

Research Articles: Impact of wildfire on the edaphic microarthropod community in a Pinus pinaster forest in central Italy

2015-05-05

Lisa C, Paffetti D, Nocentini S, Marchi E, Bottalico F, Fiorentini S, Travaglini D

IMPACT OF WILDFIRE ON THE EDAPHIC MICROARTHROPOD COMMUNITY IN A PINUS PINASTER FOREST IN CENTRAL ITALY

Abstract: The purpose of this study was to investigate the response of the soil microarthropod community to wildfire in forest ecosystems. The edaphic microarthropod communities of pine stands burned in 2001, in 2009, both in 2001 and in 2009, in 2012 were compared to an area never burned. Sampling was conducted in the spring and autumn of 2011 and 2012 in the areas burned in 2001, in 2009 and those never burned, while in the area burned in 2012, soil samples were collected in March (10 days after fire), June and September. The abundance and biodiversity of the microarthropod community were assessed. A multitemporal analysis was also carried out to assess the effect of fire on soil microarthropod abundance 5 months, 2-3 years and 10-11 years after fire. The results showed that the abundance of edaphic microarthropod communities decreased dramatically in areas burned twice, but also in areas burned once in 2009 and five months after the fire in the area burned in 2012. Different taxonomic groups did not seem to respond to fire in the same way, some taxa being more sensitive than others. Pseudoscorpionida decreased in both the short- and the long-term, while Diplopoda, Thysanoptera and Symphyla showed a reduction in the intermediate- and long-term. In the short-term, Diptera and Coleoptera larvae appeared to be the most influenced taxonomic groups. Our study shows that biomonitoring is a valuable tool to investigate the reaction of forest ecosystems to fire, and that edaphic microarthropods can provide interesting answers about the direct and indirect effects of fire on soil.

Keywords: Biomonitoring, Microarthropod Community, Forest Fires, Pinus pinaster Aiton

iForest 8 (6): 874-883 (2015) - doi: 10.3832/ifor1404-008
https://iforest.sisef.org/contents/?id=ifor1404-008

Research Articles: First vs. second rotation of a poplar short rotation coppice: leaf area development, light interception and radiation use efficiency

Broeckx LS, Vanbeveren SP, Verlinden MS, Ceulemans R — 2015-04-27

Broeckx LS, Vanbeveren SP, Verlinden MS, Ceulemans R

FIRST VS. SECOND ROTATION OF A POPLAR SHORT ROTATION COPPICE: LEAF AREA DEVELOPMENT, LIGHT INTERCEPTION AND RADIATION USE EFFICIENCY

Abstract: Given the high expectations for lignocellulosic biomass as one of the potential solutions for energy security and climate change mitigation, commercial scale studies over several rotations are crucial to assess the potential and the sustainability of short rotation coppice (SRC) cultures for bioenergy. The first and the second rotation of the SRC poplar (Populus) plantation of the present study differed significantly in biomass yield and in productivity determinants and their relationships. Coppicing enhanced leaf area development, radiation interception and woody biomass productivity. High total leaf area and radiation use efficiency (RUE) equally contributed to the high biomass yield during the establishment rotation, while RUE became the most important determinant of biomass yield after coppice. The study confirmed the significant genotypic variation in biomass productivity and its underlying determinants, also among more recently selected poplar genotypes. The absence of a correlation between intercepted radiation and RUE suggests the potential of selecting for genotypes combining high total leaf area and photosynthetic carbon uptake in future breeding programs for yield maximization towards sustainable bioenergy cultivation.

Keywords: Genotypic Variation, Leaf Area Index, Aboveground Woody Biomass Productivity, Bioenergy, Populus, POPFULL

iForest 8 (5): 565-573 (2015) - doi: 10.3832/ifor1457-008
https://iforest.sisef.org/contents/?id=ifor1457-008

Research Articles: Does management improve the state of chestnut (Castanea sativa L.) on Belasitsa Mountain, southwest Bulgaria?

2015-04-27

Zlatanov T, Velichkov I, Georgieva M, Hinkov G, Zlatanova M, Gogusev G, Eastaugh CS

DOES MANAGEMENT IMPROVE THE STATE OF CHESTNUT (CASTANEA SATIVA L.) ON BELASITSA MOUNTAIN, SOUTHWEST BULGARIA?

Abstract: Chestnut forests in the Belasitsa Mountain region of southwest Bulgaria were traditionally intensively managed as orchard-like stands for nut production. More recently, management intensity has been sharply reduced as a result of rural abandonment, which combined with the effects of chestnut blight has led to marked structural changes in these forests. The focus of this paper is on the seed-based regeneration potential and seedling survival of chestnut in mixed stands managed over the past 15 years. Results suggest that management of stands under a high-forest system is appropriate, and regeneration from seed has advantages over coppicing if competing species can be controlled. An investigation into “sanitation cutting” performed since the 1990s shows that this had not a successful response to blight infestations.

Keywords: Castanea sativa, Chestnut Blight, High-forest System, Seed-based Regeneration

iForest 8 (6): 860-865 (2015) - doi: 10.3832/ifor1420-008
https://iforest.sisef.org/contents/?id=ifor1420-008

Research Articles: Earlywood vessel features in Quercus faginea: relationship between ring width and wood density at two sites in Portugal

Sousa VB, Louzada JL, Pereira H — 2015-04-27

Sousa VB, Louzada JL, Pereira H

EARLYWOOD VESSEL FEATURES IN QUERCUS FAGINEA: RELATIONSHIP BETWEEN RING WIDTH AND WOOD DENSITY AT TWO SITES IN PORTUGAL

Abstract: Wood anatomy holds relevant information for tree development and timber quality (e.g., wood density), which is important for the sustainability of the species. Quercus faginea Lam. (Portuguese or Lusitanian oak) is an autochthonous Mediterranean oak species characterized by a shrinking natural distribution area and use abandonment. We studied the variation of several wood properties and their relationships with the aim of determining and possibly increasing the wood economic value of this species. The anatomical features of earlywood vessels (area, number, frequency and proportion) were investigated in twenty Q. faginea trees sampled at two locations within the natural distribution of the species in Portugal. Moreover, we analyzed the variation of vessel features from pith to bark, the radial growth and the wood density to search for patterns and relationships among the analyzed parameters. Mean earlywood vessel area increased with cambial age up to 60-70 years and then leveled off. An inverse pattern was found for the number of vessels per ring beyond that age. Similar radial patterns of all vessel features were found at both sites, and no significant differences in earlywood vessel area were found between sites. The within-tree development of earlywood vessels was age-related, though not influenced by growth. Earlywood vessel features explained the variation of wood density, i.e., wood density of Q. faginea was strongly negatively correlated with both mean vessel area and proportion.

Keywords: Quercus faginea, Earlywood Vessels, Wood Density, Ring Width, Variation

iForest 8 (6): 866-873 (2015) - doi: 10.3832/ifor1346-008
https://iforest.sisef.org/contents/?id=ifor1346-008

Research Articles: Changes in vegetation diversity and composition following livestock removal along an upland elevational gradient

Davies GM, Bodart J — 2015-04-22

Davies GM, Bodart J

CHANGES IN VEGETATION DIVERSITY AND COMPOSITION FOLLOWING LIVESTOCK REMOVAL ALONG AN UPLAND ELEVATIONAL GRADIENT

Abstract: European heathland habitats are cultural landscapes derived from previously-forested ecosystems. Heathlands are of significant conservation interest but have experienced prolonged degradation due to a range of factors including overgrazing by domestic livestock. There is growing recognition of the need to restore upland landscapes to produce a diverse mosaic of woodlands, heathlands and forest edge ecotones. In some studies stock removal has been sufficient to promote heathland recovery, but often more intensive interventions are required. Few studies have specifically examined how abiotic gradients associated with changing elevation might relate to restoration success. We examined differences in vegetation between grazed and restored areas over a 500 m elevational gradient split across two hillsides that were part of a landscape-scale restoration project in the Scottish Southern Uplands. Species alpha and gamma diversity showed non-linear responses to elevation but the effects of grazing differed between sites. Grazing increased diversity on the lower elevation site but reduced it at higher elevations. The differing effects of grazing with elevation can be interpreted in the context of levels of competition and likely impacts on rates of colonization and extinction. Differences in community composition were assessed using PERMANOVA, NMDS and Cluster Analysis and were primarily controlled by elevation with no significant effect of grazing. The keystone heathland species Calluna vulgaris was not recorded in any of our monitoring plots but some other dwarf shrubs were common. Changes in community structure following stock removal are slow on upland sites but initial impacts interact strongly with abiotic site conditions and pre-restoration vegetation composition. During large-scale restoration it is therefore vital to consider how widely-applied treatments might differ in their effects across landscapes. Changes in diversity may provide a useful early indicator of important ecological processes and likely directions of change.

Keywords: Calluna vulgaris, Community Change, Grazing, Heathland, Moorland, Restoration, Scotland

iForest 8 (5): 582-589 (2015) - doi: 10.3832/ifor1557-008
https://iforest.sisef.org/contents/?id=ifor1557-008

Research Articles: Methods to inventory and strip thin in dense stands of aspen root suckers

Headlee WL, Hall RB — 2015-04-22

Headlee WL, Hall RB

METHODS TO INVENTORY AND STRIP THIN IN DENSE STANDS OF ASPEN ROOT SUCKERS

Abstract: Aspen and their hybrids have demonstrated high biomass productivity and can produce abundant regeneration in the form of root suckers. This makes aspen particularly intriguing for bio-energy production, because replanting costs can be avoided and additional biomass can be obtained by thinning the regenerating stands. Mechanical strip thinning (removal of stems in parallel strips) has been proposed as a fast and efficient method for capturing biomass that would otherwise be lost to mortality in such stands. However, determining the appropriate width for the residual rows is challenging, due to the difficulty of conducting inventories with traditional sampling tools and the variability in gap sizes between root suckers in the residual rows. In this study, we describe the development and testing of a simple inventory tool that may be used to conduct either fixed-area or variable-radius sampling in these stands. Also described is the development and testing of an equation that uses such inventory data along with Poisson distribution theory to predict the size of the largest gap between root suckers within residual rows, which in turn can be used to inform strip thinning operations. Based on the promising results of our limited tests, we encourage further evaluation of these methods with regeneration from planted and natural aspen stands, as well as other root suckering species.

Keywords: Bio-energy, Coppice, Poisson Distribution, Populus, Thinning

iForest 8 (5): 590-595 (2015) - doi: 10.3832/ifor1461-008
https://iforest.sisef.org/contents/?id=ifor1461-008

Research Articles: Soil chemical and physical status in semideciduous Atlantic Forest fragments affected by atmospheric deposition in central-eastern São Paulo State, Brazil

2015-04-22

Lopes MIMS, Ribeiro Dos Santos A, Zuliani Sandrin Camargo C, Bulbovas P, Giampaoli P, Domingos M

SOIL CHEMICAL AND PHYSICAL STATUS IN SEMIDECIDUOUS ATLANTIC FOREST FRAGMENTS AFFECTED BY ATMOSPHERIC DEPOSITION IN CENTRAL-EASTERN SãO PAULO STATE, BRAZIL

Abstract: The expansion of agricultural, urban and industrial areas in the São Paulo State (SE Brazil) led to the fragmentation of the original semideciduous Atlantic Forest into small, patchy forest remnants. Anthropogenic activities produce a variety of pollutants affecting many ecological processes in these remaining forest fragments through soil acidification and fertilization. In this study, we investigated the soil chemical and physical status of six forest remnants (Paulínia, Holambra, Americana, Jaguariúna, Campinas and Cosmópolis) differently affected by industrial, rural and urban pollution in central-eastern São Paulo in order to determine the soil potential to buffer the inputs of pollutants. Soil samples from 0-10, 10-20 and 20-40 cm depths were collected in the dry and the wet season and the following variables were analyzed: soil texture, pH in CaCl2 solution, exchangeable cations and exchange capacity, organic carbon, total nitrogen, extractable sulfur, phosphorus and heavy metals. Distinct buffering capacities were observed in industrial and in rural and urban areas, primarily due to the natural characteristics of the soils, such as soil texture, acidification and organic matter. The forest soils affected by atmospheric deposition from the industrial complex (Paulínia and Americana) were more sandy and acidic (pH = 3.6) than those near rural and urban sources (pH = 4.5). The optimal chemical conditions (high contents of organic matter, exchangeable bases, nitrogen, phosphorus and sulfur) were found in the clay soils of forest remnants located in Campinas and Jaguariúna, which were more affected by rural or urban pollution than by industrial emissions. Such clay soils provide the highest buffering capacity against environmental impacts in the study region.

Keywords: Tropical Soils, Atlantic Forest, Urban, Rural and Industrial Pollution, Soil Acidification, Buffering Capacity

iForest 8 (6): 798-808 (2015) - doi: 10.3832/ifor1258-007
https://iforest.sisef.org/contents/?id=ifor1258-007

Research Articles: Patterns of carbon allocation in a chronosequence of Caragana intermedia plantations in the Qinghai-Tibet Plateau

Tian Y, Cao J, Yang X, Shan N, Shi Z — 2015-04-08

Tian Y, Cao J, Yang X, Shan N, Shi Z

PATTERNS OF CARBON ALLOCATION IN A CHRONOSEQUENCE OF CARAGANA INTERMEDIA PLANTATIONS IN THE QINGHAI-TIBET PLATEAU

Abstract: Revegetation is being considered as a mitigation option to improve the ecological environment and reduce the atmospheric carbon (C) dioxide concentrations of regions experiencing desertification. This study assessed the development of the above- and belowground ecosystem C pools in a chronosequence of four Caragana intermedia plantations (3, 12, 27, and 37 years old) in the desertified region of the Qinghai-Tibet Plateau, China. The biomass C stock of the total shrub and under-canopy increased with stand age. The soil inorganic carbon (SIC) pool in the soil C stocks was approximately 3 to 7 times larger than the soil organic carbon (SOC) storage. Both SIC and SOC increased after revegetation. However, the contribution of SIC to the total ecosystem C stock decreased from 87% in the 3-year-old plantation to 85%, 75%, and 72% in the 12-, 27-, and 37-year-old plantations, respectively. The total ecosystem C pool exhibited a greater increase in the shrub plantations than in the mobile dunes, but the total C stock of the stands changed slightly with time. Soil C, including SOC and SIC, was the major contributor to the total ecosystem C stock for all shrub plantations. The aboveground shrub biomass became the secondary ecosystem C pool in older srands. The results of this study indicate that revegetation in desertification ecosystems has a significant impact on SIC, SOC, and total ecosystem C pools. Furthermore, the total ecosystem C pool reached a relatively stable state after sand-binding stands.

Keywords: Biomass Carbon, Shrub Plantation, Soil Organic Carbon, Soil Inorganic Carbon

iForest 8 (6): 756-764 (2015) - doi: 10.3832/ifor1193-007
https://iforest.sisef.org/contents/?id=ifor1193-007

Research Articles: Drought effects on the floristic differentiation of Greek fir forests in the mountains of central Greece

Samaras DA, Gaertner S, Reif A, Theodoropoulos K — 2015-04-08

Samaras DA, Gaertner S, Reif A, Theodoropoulos K

DROUGHT EFFECTS ON THE FLORISTIC DIFFERENTIATION OF GREEK FIR FORESTS IN THE MOUNTAINS OF CENTRAL GREECE

Abstract: Greek fir (Abies cephalonica Loudon) grows in montane Mediterranean climates characterized by dry, warm summers. Drought is an important climatic feature of these montane ecosystems as it affects the floristic composition, structure and distribution of plant communities. The Oxia-North Vardousia mountain system is one of the few areas in Greece with an extensive, well-preserved Greek fir forest. This study aims at describing the Greek fir forest vegetation of such area and determining the drought-related factors affecting their floristic composition and differentiation. Vegetation relevés were classified and ordinated. The impact of drought-related variables on the vegetation composition was analyzed. A cluster analysis was used to reveal the most important factor for the discrimination of the main plant communities and to determine the drought threshold between them. Two plant communities that reflect the differentiation of the Greek fir forests in central Greece into xerophytic and mesophytic forest communities were described. Each community was divided into two sub-communities. The elevational distribution of Greek fir forests in the mountains of central Greece follows a drought gradient linked to the two main climatic components of drought, precipitation and potential evapotranspiration. The combination of these two drought-related variables into a suitable humidity index was found to adequately differentiate the xerophytic from the mesophytic forest communities and define their drought threshold.

Keywords: Abies cephalonica, Aridity, Habitat Differentiation, Humidity Index, Plant Communities, Synecology, Syntaxonomy, Sterea Ellas

iForest 8 (6): 786-797 (2015) - doi: 10.3832/ifor1214-007
https://iforest.sisef.org/contents/?id=ifor1214-007

Research Articles: Estimating the mechanical stability of Pinus nigra Arn. using an alternative approach across several plantations in central Italy

Cantiani P, Chiavetta U — 2015-04-08

Cantiani P, Chiavetta U

ESTIMATING THE MECHANICAL STABILITY OF PINUS NIGRA ARN. USING AN ALTERNATIVE APPROACH ACROSS SEVERAL PLANTATIONS IN CENTRAL ITALY

Abstract: Black pine has been used often in central and southern Italy to reforest mountainous areas depleted by the intensive use of natural resources. The main purpose of establishing pine forests in Italy was to protect the soil from excessive erosion, and also to facilitate the natural succession toward mixed forests with deciduous species. The most common silvicultural treatments in Europe currently aim at maximizing the stability of the stands and facilitating the transition from pure to mixed stands comprising a larger component of native tree species. In this work, we investigated the relationships between the living whorls number and four indexes of individual tree stability: the slenderness ratio, the crown depth, the crown projection, and an eccentricity index of the canopy. The data set used was composed of 1098 trees from ten black pine plantations located in central Italy. Our results demonstrate that the living whorls number can be handily used to predict the slenderness ratio with an error of 18%. A non-parametric model based on a reduced number of field measures was obtained as a support for thinning operations aimed at improving single tree stability.

Keywords: Black Pine, Tree Stability, Living Whorl Number, Slenderness Ratio, Crown Depth, Crown Projection, Crown Eccentricity

iForest 8 (6): 846-852 (2015) - doi: 10.3832/ifor1300-007
https://iforest.sisef.org/contents/?id=ifor1300-007

Research Articles: Effect of salt and drought on growth, physiological and biochemical responses of two Tamarix species

Dawalibi V, Monteverdi MC, Moscatello S, Battistelli A, Valentini R — 2015-03-25

Dawalibi V, Monteverdi MC, Moscatello S, Battistelli A, Valentini R

EFFECT OF SALT AND DROUGHT ON GROWTH, PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF TWO TAMARIX SPECIES

Abstract: Tamarix trees are considered of particular interest for afforestation and reforestation of degraded areas prone to salinity and drought. In this study, a comparison of the performance and physiological responses of two species of Tamarix grown in saline and dried soils was carried out. Stem cuttings of T. aphylla and T. jordanis were collected from a location in the Negev desert and the plantlets obtained were subjected to four different soil treatments under semi-controlled conditions for 14 days. The treatments were: fresh water (C); salt (S: 150 mM of NaCl); drought (D: 50% field capacity); and a combined stress (DS: 150 mM of NaCl + 50% FC). Results showed a higher tolerance to salt stress of T. jordanis as compared with T. aphylla. The maintenance of high amount of cell carbohydrates, the high capacity of carbon assimilation and the active growth were considered as markers of salt tolerance in Tamarix spp. T. aphylla showed better performances in terms of growth and biomass production than T. jordanis in dry conditions. The high accumulation of sugars found in the leaves of T. aphylla under mild drought is considered a mechanism of acclimatization. The combined stress (salt+drought) lowered the performance of plants as compared to salt and drought stress applied alone. The possible role of the accumulation of proline observed in the leaves of both species under stressful conditions is discussed.

Keywords: Tamarix, Afforestation, Salinity, Drought, Tolerance

iForest 8 (6): 772-779 (2015) - doi: 10.3832/ifor1233-007
https://iforest.sisef.org/contents/?id=ifor1233-007

Research Articles: Wildfires in Algeria: problems and challenges

Meddour-Sahar O — 2015-03-25

Meddour-Sahar O

WILDFIRES IN ALGERIA: PROBLEMS AND CHALLENGES

Abstract: In the scenario of the Mediterranean area, where about 54 000 fires and 0.4 million hectares of forest are burned and annually registered (2006-2010), the rank for Algeria is non-negligible with 4.11 million hectares of forest. The annual number of fires and the size of area burned depict a critical situation, which became rather dramatic in 2012. Climate change projections and the estimated changes to wildfire risk for the future decades (2030-2060) indicate that the entire Maghreb region, including Algeria, will be among the most affected areas of the Mediterranean. Longer fire seasons will be experienced and extended by an additional month with each passing year. Despite Algeria’s recent investments in technical means for controlling forest fires, the current suppression-oriented model seems unable to cope with such a phenomenon. Furthermore, the model is unfit in view of the approaching scenario, when fire-exclusion policies need to be complemented with fuel-reduction techniques and fire prevention management. This study aims to establish an understanding of the context and public policy issues related to wildfire management in Algeria. Data were collected by distributing questionnaires to foresters with the objective of identifying obstacles and constraints hindering the efficacy of pro-active measures. Analysis of the data gathered indicates that Algerian foresters are well aware of the importance of prevention, contrasting with current governmental policies that are predominantly oriented towards improving the technical extinction apparatus. A SWOT analysis suggests possible strategic options for improving the efficiency of wildfire control by building on strengths, eliminating weaknesses, exploiting opportunities, and mitigating threats. The results of this study may be adapted to other countries with similar problems as those of Algeria.

Keywords: Algeria, Forest Fires, MENA, Prevention Policy, SWOT Analysis

iForest 8 (6): 818-826 (2015) - doi: 10.3832/ifor1279-007
https://iforest.sisef.org/contents/?id=ifor1279-007

Research Articles: Vertical position of dry mass and elemental concentrations in Pinus sylvestris L. canopy under the different ash-nitrogen treatments

Varnagiryte-Kabašinskiene I, Stakenas V, Mikšys V, Kabašinskas A — 2015-03-25

Varnagiryte-Kabašinskiene I, Stakenas V, Mikšys V, Kabašinskas A

VERTICAL POSITION OF DRY MASS AND ELEMENTAL CONCENTRATIONS IN PINUS SYLVESTRIS L. CANOPY UNDER THE DIFFERENT ASH-NITROGEN TREATMENTS

Abstract: Compensatory biofuel ash fertilisation is recommended for managed Pinus sylvestris L. forests growing on nutrients poor Arenosols in Lithuania. We conducted an experiment between 2002 and 2005, investigating the effects of biofuel ash and nitrogen fertilisation applied to Scots Pine stands on nutrient poor Arenosols. We studied the effects of three fertilization treatments (biofuel ash, nitrogen and ash applied together with nitrogen) on dry mass and concentrations of the main nutrients (N, P, K, Ca and Mg) and other elements (Cu, Zn, Cd, Cr, Ni, and Pb) in different compartments and layers of the canopy. The biofuel ash, nitrogen fertilizers and ash applied together with nitrogen led to heavier needles in the upper and middle layers of the canopy with less effect toward the canopy base. The complex ash plus nitrogen treatment gave the strongest significant response. All treatments resulted in an increase in dry mass, but not in the length of the current year needles. The additional input of nitrogen induced higher increase in dry mass compared to the changes of N concentration in the youngest needles. On the basis of the present study results, it can be concluded that the youngest needles produced new mass per amount of nitrogen more effectively compared to older needles.

Keywords: Pinus sylvestris, Biofuel Ash, Canopy, Biomass, Nutrients

iForest 8 (6): 838-845 (2015) - doi: 10.3832/ifor1342-007
https://iforest.sisef.org/contents/?id=ifor1342-007

Research Articles: The opinions of some stakeholders on the European Union Timber Regulation (EUTR): an analysis of secondary sources

Giurca A, Jonsson R — 2015-03-19

Giurca A, Jonsson R

THE OPINIONS OF SOME STAKEHOLDERS ON THE EUROPEAN UNION TIMBER REGULATION (EUTR): AN ANALYSIS OF SECONDARY SOURCES

Abstract: The EU Timber Regulation (EUTR) is the most recent effort by the European Union (EU) to curb imports of illegally sourced timber. The regulation raises important questions concerning the international timber trade. In order to successfully implement this regulation it is of paramount importance to classify the actors concerned, and examine how they regard it. The current study collects and summarizes opinion statements of stakeholders as found in different online publications. Though the problem of illegal logging and its associated trade is acknowledged by all parties, there are concerns as to whether the EUTR is the proper instrument to address this issue. Whilst some stakeholders see the EUTR as advantageous for their businesses, others see it as an impediment. Law enforcement, lack of guidance, and bureaucracy were other issues raised. The trade-off between effective legislation and ease of trade was also highlighted. Transparent and consistent application of the EUTR, with clear guidelines for exerting due diligence, should diminish the degree of possible unwanted side-effects such as trade diversion and substitution of temperate timber for tropical timber.

Keywords: EUTR, Actors, Opinions, Content Analysis, Frames

iForest 8 (5): 681-686 (2015) - doi: 10.3832/ifor1271-008
https://iforest.sisef.org/contents/?id=ifor1271-008

Research Articles: Spread intensity and invasiveness of sycamore maple (Acer pseudoplatanus L.) in Lithuanian forests

Straigyte L, Baliuckas V — 2015-03-19

Straigyte L, Baliuckas V

SPREAD INTENSITY AND INVASIVENESS OF SYCAMORE MAPLE (ACER PSEUDOPLATANUS L.) IN LITHUANIAN FORESTS

Abstract: The primary objectives of this study were to estimate seedling abundance, spread intensity, and invasiveness of sycamore maple (Acer pseudoplatanus L.) in Lithuanian forests. The species was introduced to Lithuania in 1802, and since then has subsequently become gradually invasive. Seedling understory abundance, colonization and dispersal were investigated in six forest blocks covering the principal sycamore distribution areas in southwestern Lithuania. Seedlings height and densities in the undestory were evaluated, and seedlings assigned to four height groups. Species invasiveness was estimated applying the Pest Plant Prioritization Process (PPPP), based on the Analytic Hierarchy Process (AHP) method. Results showed the average spread distance from the parent tree was 257 m, with a mean seedling number per hectare of 2064. Sycamore maple invasive score was 0.6426 (range: 0-1), the current relative to potential distribution rating was 0.57, and the social, environmental, and economic impact score was 0.1682. Such values were used to assess the Pest Plant Score for sycamore maple, obtaining a value (0.3537) lower than expectations (0.5). Results indicated that the species exhibits invasive properties and a rapid spread in the study area. Some implications of the above results in view of the upcoming climate change and the use of sycamore maple in Lithuanian forest plantations are discussed.

Keywords: Sycamore, Seedling spread, PPPP, Invasiveness, Pest Plant Score

iForest 8 (5): 693-699 (2015) - doi: 10.3832/ifor0763-007
https://iforest.sisef.org/contents/?id=ifor0763-007

Research Articles: Litter quality changes during decomposition investigated by thermal analysis

Gioacchini P, Montecchio D, Ferrari E, Ciavatta C, Masia A, George E, Tonon G — 2015-03-19

Gioacchini P, Montecchio D, Ferrari E, Ciavatta C, Masia A, George E, Tonon G

LITTER QUALITY CHANGES DURING DECOMPOSITION INVESTIGATED BY THERMAL ANALYSIS

Abstract: The litter decomposition process depends on the litter chemical composition, especially the ratio between more labile compounds, cellulose, and the recalcitrant lignin and waxes. Their determination is crucial to predict the process, though lignin measurement presents some limitations due to drawbacks of the different methods. Thermal analysis has been successfully applied to several organic materials in order to obtain quali-quantitative information of the chemical structure of the sample. In this work TG-DTA was used in a short-term litter decomposition study of two broadleaf forest stands of contrasting ages, and the results were compared to those obtained with a chemical method (Klason’s method) commonly used to quantify cellulose and lignin. TG-DTA was applied to the litter and to the cell walls (CW) extracted from the litter, whose cellulose and lignin content was determined using the Klason’s method. When applied to litter, thermal analysis showed a weak correlation with the Klason’s method, though it allowed the detection of the dynamics of waxes, that increased during the decomposition and could influence the later stages of the process. Contrastingly, a good correlation between cellulose and lignin determined with the two methods was found when TG-DTA was applied to the CW. In this case TG-DTA, according to NMR data, also highlighted the changes in the CW chemical structure compared with that of the litters, in particular the loss of waxes and the decreased thermostability of aromatic components. Moreover, a new concept of quality of the decomposing litter, based on the balance between the energy stored in the litter and the energy needed to release it obtained by thermal analysis, was recently introduced. Samples of the old forest litter had an initial energetic balance more favorable than those collected in the young stand. At the end of the period, the decrease in litter quality was greater in the young than in the old forest samples, due to the combined effect of the higher degradation of thermolabile substances and the accumulation of more thermostable components. Thermal analysis seems to have a good potential in litter decomposition studies, as it can link structural and energetic changes during the process.

Keywords: Thermal Analysis, Litter Quality, NMR, Cellulose, Lignin, Cell Wall

iForest 8 (6): 827-837 (2015) - doi: 10.3832/ifor1297-007
https://iforest.sisef.org/contents/?id=ifor1297-007

Research Articles: On the geometry and allometry of big-buttressed trees - a challenge for forest monitoring: new insights from 3D-modeling with terrestrial laser scanning

Nölke N, Fehrmann L, I Nengah SJ, Tiryana T, Seidel D, Kleinn C — 2015-03-02

Nölke N, Fehrmann L, I Nengah SJ, Tiryana T, Seidel D, Kleinn C

ON THE GEOMETRY AND ALLOMETRY OF BIG-BUTTRESSED TREES - A CHALLENGE FOR FOREST MONITORING: NEW INSIGHTS FROM 3D-MODELING WITH TERRESTRIAL LASER SCANNING

Abstract: In many old-growth natural and close-to-natural forest types, notably in humid tropical forests, a relatively small number of very tall trees contribute considerably to stand basal area and biomass. Such trees often show distinct buttress roots with irregular non-convex shapes. Buttresses are complex structures in the lowest stem section, where most tree biomass is located. The methods used to assess the diameter of buttressed trees have a large impact on the determination of volume and biomass, as well as on the resulting estimates of the aboveground carbon stock in tropical forests. As the measurement of diameter at breast height (DBH at 1.3 m) is not feasible in such conditions, the diameter above buttress (DAB), where the cylindrical bole of the tree begins, is usually measured and included as an independent variable in biomass models. We conducted a methodological study aimed at determining the volume and biomass of individual buttressed trees belonging to several tropical species by the application of terrestrial laser scanning (TLS). The geometry and allometry of the buttresses, as well as the change with height along the stem in buttress volume and cross-sectional area were analyzed. Our results suggest that the relationship between cross-sectional areas at DAB height (ADAB) and the actual tree basal area measured at 1.3 m height is relatively strong (R² = 0.87) across a range of different species, buttress morphologies and tree dimensions. Furthermore, the change in stem cross-sectional area with tree height was surprisingly similar and smooth. Despite the small number of trees sampled, the methodological approach used in this study provided new insights on the very irregular geometry of buttressed trees. Our results may help improving the volume and biomass models for buttressed trees, that are crucial contributors to carbon stocks in tropical forests.

Keywords: Biomass, Morphology, Volume, Form Factor

iForest 8 (5): 574-581 (2015) - doi: 10.3832/ifor1449-007
https://iforest.sisef.org/contents/?id=ifor1449-007

Research Articles: Potential impacts of regional climate change on site productivity of Larix olgensis plantations in northeast China

Shen C, Lei X, Liu H, Wang L, Liang W — 2015-03-02

Shen C, Lei X, Liu H, Wang L, Liang W

POTENTIAL IMPACTS OF REGIONAL CLIMATE CHANGE ON SITE PRODUCTIVITY OF LARIX OLGENSIS PLANTATIONS IN NORTHEAST CHINA

Abstract: Climate change is expected to substantially affect forest site productivity. However, its effects may vary depending on the climate scenario, region and tree species. We chose Larix olgensis in northeast China to investigate the responses of forest site productivity to regional climate change using a generalized additive model (GAM). Based on site index data and climate variables from 335 townships across the Jilin Province, we developed a climate-sensitive forest site index model, which accounted for 72.9% of the variation in the site index at the referred age of 20 (SI20). Our results indicated that climatic and geographic factors significantly affect forest site productivity. The geographic location, mean annual temperature, mean annual precipitation and mean temperature differential were found to be statistically significant explanatory variables. We predict that the change of mean SI20 would vary from 0.3 m to -0.8 m (2.2% to -5.9%) by 2050 and from 0.5 m to -1.6 m (3.7% to -11.8%) by 2070 under three BC-RCP scenarios with rising temperature and increasing precipitation. Our study suggests that climate is an important factor affecting forest site productivity. Future climate changes could affect the forest site productivity both positively and negatively for Larix olgensis in northeast China. The relationship between climate and forest site productivity has strong implications for adaptive forest management and needs to be considered in forest management planning under future climate change.

Keywords: Site Productivity, Climate Change, Potential Impacts, Larix Olgensis

iForest 8 (5): 642-651 (2015) - doi: 10.3832/ifor1203-007
https://iforest.sisef.org/contents/?id=ifor1203-007

Research Articles: Behavior of pubescent oak (Quercus pubescens Willd.) wood to different thermal treatments

Todaro L, Rita A, Negro F, Moretti N, Saracino A, Zanuttini R — 2015-02-16

Todaro L, Rita A, Negro F, Moretti N, Saracino A, Zanuttini R

BEHAVIOR OF PUBESCENT OAK (QUERCUS PUBESCENS WILLD.) WOOD TO DIFFERENT THERMAL TREATMENTS

Abstract: Quercus pubescens Willd. is a common oak species in the Mediterranean area, where it is currently exploited mainly for purposes such as firewood. To improve the technological properties of its wood, various steaming and/or heat treatments were applied to 160 wood samples from a southern Italian stand, cut from either sapwood or heartwood, while 20 samples served as controls. Steaming was carried out in an autoclave at 120 °C, whereas heat treatments were performed in an oven at 150 or 200 °C for 3 or 6 h. The equilibrium moisture content, swelling, mass loss, wood density, compression strength, color variation, and lignin content of the samples were measured and compared among treatments. The swelling and water adsorption of wood samples decreased due to the hydrothermal treatments. The mass loss was strictly related to the temperature and duration of the heat treatments, whereas it was not influenced by the steaming treatment. The average axial compression strength value was positively influenced by the combination of steaming and heat treatments. A significant and general darkening of color was also observed for the harshest treatments, while an increase of lignin content was detected mainly in the sapwood. Thus, pubescent oak wood subjected to steaming and heat treatments may acquire useful characteristics suitable for its industrial use.

Keywords: Steaming, Moisture Content, Swelling, Color, Strength, Ray Cells

iForest 8 (6): 748-755 (2015) - doi: 10.3832/ifor1348-007
https://iforest.sisef.org/contents/?id=ifor1348-007

Short Communications: Influences of Black Locust (Robinia pseudoacacia L.) afforestation on soil microbial biomass and activity

Bolat I, Kara O, Sensoy H, Yüksel K — 2015-02-16

Bolat I, Kara O, Sensoy H, Yüksel K

INFLUENCES OF BLACK LOCUST (ROBINIA PSEUDOACACIA L.) AFFORESTATION ON SOIL MICROBIAL BIOMASS AND ACTIVITY

Abstract: Black locust is a tree species considered suitable for afforestation in Turkey because of its rapid growth and ability to fix atmospheric nitrogen in disturbed soil ecosystems. Quantitative indicators of soil health and quality can be usefully derived from a data set of soil physical, chemical and microbial characteristics. In this study changes in soil characteristics after afforestation with black locust were assessed by comparing several afforestation sites with control (no vegetation) sites randomly chosen along the roadside in Ulus-Bartin, the western Black Sea region (Turkey). Results showed that some physical and chemical characteristics of the soil (soil bulk density, clay content, soil organic C and total N) were higher at the afforestation sites as compared with the control sites. Similarly, afforestation sites showed higher values for mean soil microbial biomass C (afforestation: 311.97 µg g-1;control: 149.68 µg g-1) and N (afforestation: 43.07 µg g-1; control: 19.21 µg g-1), and basal respiration (afforestation: 0.303 µg CO2-C g-1 h-1; control: 0.167 µg CO2-C g-1 h-1). However, the mean metabolic quotient (qCO2) assessed at the control sites was higher (1.47 mg CO2-C g-1 Cmic h-1) than that observed the afforestation sites (0.96 mg CO2-C g-1 Cmic h-1), likely due to difficulties in the utilization of organic substrates by the microbial community. In addition, the correlation between the qCO2 and Cmic/Corg percentages was negative (r = - 0.586, P < 0.01) in both sites. Our results indicated that afforestation with black locust could be advantageous, not only for soil improvement and regeneration, but also for sustainable land management.

Keywords: Basal Respiration, Cmic/Corg Percentage, Cmic/Nmic Ratio, Metabolic Quotient (qCO2), Nitrogen Fixation

iForest 9 (1): 171-177 (2016) - doi: 10.3832/ifor1410-007
https://iforest.sisef.org/contents/?id=ifor1410-007

Research Articles: A comparison of models for quantifying growth and standing carbon in UK Scots pine forests

Lonsdale J, Xenakis G, Mencuccini M, Perks M — 2015-02-02

Lonsdale J, Xenakis G, Mencuccini M, Perks M

A COMPARISON OF MODELS FOR QUANTIFYING GROWTH AND STANDING CARBON IN UK SCOTS PINE FORESTS

Abstract: Scots pine is the most abundant native conifer in the UK. A stand level dynamic growth (SLeDG) model is parametrised for British Scots pine stands for the first time. This model predicts stands annually based on their current state, and allows for changes in forest management. Stand growth and carbon storage predictions using this model were compared with those of the yield look-up package ForestYield, and a process-based model (3PGN). Predictions were compared graphically over an 100 year rotation, and strengths and weaknesses of each were considered. The SLeDG parametrisation provided forecasts of Scots pine growth with percentage mean absolute difference < 12% for all state variables. The model comparison showed that similar outputs were predicted by all three models, with the greatest variation in the yield table based prediction of volume and biomass. Future advances in data availability and computing power should allow for greater use of process-based models, but in the interim more flexible dynamic based growth models may be more useful than static yield tables for providing predictions which extend to non-standard management prescriptions and estimates of early growth and yield.

Keywords: Growth, Yield, Carbon, Modelling, Dynamical-systems, 3PG, ForestYield

iForest 8 (5): 596-605 (2015) - doi: 10.3832/ifor1403-008
https://iforest.sisef.org/contents/?id=ifor1403-008

Research Articles: Soil respiration and carbon balance in a Moso bamboo (Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens) forest in subtropical China

Tang X, Fan S, Qi L, Guan F, Cai C, Du M — 2015-02-02

Tang X, Fan S, Qi L, Guan F, Cai C, Du M

SOIL RESPIRATION AND CARBON BALANCE IN A MOSO BAMBOO (PHYLLOSTACHYS HETEROCYCLA (CARR.) MITFORD CV. PUBESCENS) FOREST IN SUBTROPICAL CHINA

Abstract: Understanding spatial and temporal variation in soil respiration (RS) in different forest ecosystems is crucial to estimate the global carbon balance. Bamboo forest is a special forest type in southern China covering an area of 5.38 million ha, 70% of which are Moso bamboo (Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens) forests. Bamboo forests contribute more than 10% to the whole carbon stock of forest ecosystems in China, and therefore play a critical role in the regional and national carbon balance. However, little information on the seasonal dynamic of RS and the carbon balance of Moso bamboo forests is available. In this study, litter removal and trenching methods were applied to partition RS into root respiration (RR), litter respiration (RL) and soil organic matter derived respiration (RM), and to study their seasonal dynamics and carbon balance in a pure Moso bamboo forest. Monthly RS, its source components and combined monthly environmental factors were measured. RS and its source components showed a significant seasonal variability with higher values from June to August and lower values from December to February driven by soil temperature and moisture (P < 0.001). Annual average RS, RR, RL and RM were 2.37, 0.69, 0.58 and 1.10 μmol m-2 s-1 with Q10 values of 1.25, 1.15, 1.19 and 1.26, respectively. Annual RS was 8.97 t C ha-1, and RR, RL and RM contributed 29%, 22% and 49%, respectively. Annual NEP was 4.72 t C ha-1 y-1, indicating that the Moso bamboo forest studied is a significant carbon sink.

Keywords: Soil Respiration, Source Components, Soil Temperature, Soil Moisture, Net Ecosystem Production

iForest 8 (5): 606-614 (2015) - doi: 10.3832/ifor1360-007
https://iforest.sisef.org/contents/?id=ifor1360-007

Research Articles: Nitrogen removal and its determinants in hybrid Populus clones for bioenergy plantations after two biennial rotations in two temperate sites in northern Italy

Paris P, Mareschi L, Sabatti M, Tosi L, Scarascia-Mugnozza G — 2015-02-02

Paris P, Mareschi L, Sabatti M, Tosi L, Scarascia-Mugnozza G

NITROGEN REMOVAL AND ITS DETERMINANTS IN HYBRID POPULUS CLONES FOR BIOENERGY PLANTATIONS AFTER TWO BIENNIAL ROTATIONS IN TWO TEMPERATE SITES IN NORTHERN ITALY

Abstract: The sustainability of bioenergy coppice plantations is strongly affected by the Nitrogen (N) balance, whose removal is very high due to the frequent harvest of large quantities of biomass composed of small-sized shoots. Poplar bioenergy coppice plantations could have a Nitrogen removal comparable to herbaceous crops. In this study, five hybrid poplar genotypes (“AF2”, “AF6”, “Monviso”, “83.148.041”, “I214”) were compared for tree morphological traits related to yield, N removal in the harvested biomass and Nitrogen wood concentration (N%) after two biennial coppice rotations in two experimental plantations located in northern Italy. N removal was primarily influenced by biomass production, and linear positive relationships between biomass yield and N removal were established. N removal also varied greatly among genotypes due to clonal differences in yield and in N%, in relation to significant differences among clones for their branching and sprouting habits. In the first rotation, branchiness was positively correlated to N% with a significant coefficient of determination (R2=0.813), while at the end of the second rotation it was also significantly correlated to the shoots per stool ratio (R2=0.804). “Monviso” and “83.148.041” were the clones showing the highest yield, but also a high N% associated to an high level of branchiness and shoots per stool ratio. Our results highlight that poplar genotype selection for sustainable N management should be aimed at genotypes with low wood N concentration, coupling high yield with low branching and sprouting habits as in the case of the clone “AF2”.

Keywords: Branching Habit, Coppice Plantations, Fertilization, Growth Traits, Sprouting Habit

iForest 8 (5): 668-676 (2015) - doi: 10.3832/ifor1254-007
https://iforest.sisef.org/contents/?id=ifor1254-007

Research Articles: Properties and prediction accuracy of a sigmoid function of time-determinate growth

Sedmák R, Scheer L — 2015-01-13

Sedmák R, Scheer L

PROPERTIES AND PREDICTION ACCURACY OF A SIGMOID FUNCTION OF TIME-DETERMINATE GROWTH

Abstract: The properties and short-term prediction accuracy of mathematical model of sigmoid time-determinate growth, denoted as “KM-function”, are presented. Comparative mathematical analysis of the function revealed that it is a model of asymmetrical sigmoid growth, which starts at zero size of an organism and terminates when it reaches its final size. The function assumes a finite length of the growth period and includes a parameter interpretable as the expected lifespan of the organism. Moreover, the possibility for growth curve inflexion at any age is possible, so the function can be used for modelling of S-shaped growth trajectories with various degree of asymmetry. These good theoretical predispositions for realistic growth predictions were empirically evaluated. The KM-function used in three and four-parameter forms was compared with three classical (Richards, Korf and Weibull) growth functions employing two parameterisation methods - nonlinear least squares (NLS) and Bayesian method. The evaluation was conducted on the basis of the tree diameter series obtained from stem analyses. The main empirical findings are: (i) if the minimisation of the prediction bias is required, the KM-function in three-parameter form in connection with Bayes parameterisation can be recommended; (ii) if the minimisation of root square error (RMSE) is required, the best short-term prediction results for a particular dataset were obtained with four-parameter Weibull function employing NLS parameterisation; (iii) moreover, three-parameter functions parameterised by Bayesian methods show a considerably smaller RMSE by 15-25% as well as smaller biases by 40-60% than four-parameter functions employing NLS. Overall, all analyses confirmed relative usefulness of the KM-function in comparison with classical growth functions, especially in connection with Bayesian parameterisation.

Keywords: Growth Function, Determinate Growth, Nonlinear Least Squares, Bayes, Prediction

iForest 8 (5): 631-637 (2015) - doi: 10.3832/ifor1243-007
https://iforest.sisef.org/contents/?id=ifor1243-007

Research Articles: Changes in aboveground biomass following alternative harvesting in oak-hickory forests in the eastern USA

Chen J, Xu J, Jensen R, Kabrick J — 2015-01-13

Chen J, Xu J, Jensen R, Kabrick J

CHANGES IN ABOVEGROUND BIOMASS FOLLOWING ALTERNATIVE HARVESTING IN OAK-HICKORY FORESTS IN THE EASTERN USA

Abstract: Managing forest lands for the sustainability of ecosystem functions and services by developing and implementing sound silvicultural methods through site-specific practices is a core concept in ecosystem management. In this study, we used long-term data collected at the extensive plots of the Missouri Forest Ecosystem Project (MOFEP) in the southeastern Missouri Ozarks (USA) to study the changes in aboveground biomass (AGB) under three silvicultural treatments: even-aged management sites (EAM), uneven-aged management sites (UAM), and non-harvested management sites (NHM). Treatments changed the magnitude of AGB dynamics. The forests maintained an AGB of 147.9 Mg ha-1 in 1990 and it increased to 175.6 Mg ha-1 by 2009. The forests were manipulated with four treatments: clear-cut, non-harvest, uneven-aged single-tree, and uneven-aged group selection and yielded AGB values of 30.7, 139.5, 125.7, and 148.7 Mg ha-1 of AGB in 2009, respectively. Over the 18-year study period, these forests accumulated 1.78 ± 0.26 Mg ha-1 yr-1, ranging from 1.60 to 1.94 Mg ha-1 yr-1 at the NHM plots. Changes in the net AGB growth rate were contributed by different growth rates of live trees and mortality and exhibited clear intra-annual variation during the five sampling periods. We observed a decreasing contribution of Quercus velutina (black oak) AGB (~6%), an increasing trend for Q. alba (white oak), and a stable change for Q. coccinea (scarlet oak) during the study period.

Keywords: Aboveground Biomass, MOFEP, Oak-hickory Forest, Forest Management, Alternative Harvest, Carbon

iForest 8 (5): 652-660 (2015) - doi: 10.3832/ifor1349-007
https://iforest.sisef.org/contents/?id=ifor1349-007

Research Articles: Exploring the potential behavior of consumers towards transgenic forest products: the Greek experience

Tsourgiannis L, Kazana V, Iakovoglou V — 2015-01-13

Tsourgiannis L, Kazana V, Iakovoglou V

EXPLORING THE POTENTIAL BEHAVIOR OF CONSUMERS TOWARDS TRANSGENIC FOREST PRODUCTS: THE GREEK EXPERIENCE

Abstract: Recently, the interest in wood products and bioenergy applications of transgenic forest trees is increasing worldwide, though plantations have been established to this purposes only in China. Information on the anticipated attitudes of consumers towards products from genetically-modified forest trees would therefore be of a particular interest both for developers and policy makers. This study investigated the purchasing behavior of potential Greek consumers towards the products from transgenic forest trees. In 2011, a survey was conducted based on randomly selected interviews of 418 potential consumers from all over Greece. Principal Components Analysis (PCA) was performed to identify the main factors affecting the potential purchasing behavior of consumers towards products from transgenic forest trees. Hierarchical and non- hierarchical cluster analysis was applied to PCA scores to identify homogeneous groups of consumers sharing a similar purchasing behavior. Discriminant analysis was used to cross-validate cluster membership of consumers based on PCA factors. Four groups of consumers showing similar potential purchasing behavior towards the products of transgenic forest trees were identified: (a) those interested in the quality of products; (b) those oriented towards lower prices; (c) those influenced by curiosity and labeling issues; and (d) consumers mainly interested in health safety issues and environmental impacts. Finally, a most frequent profile for each group of consumers was outlined according to their demographic characteristics and their opinions on the use of transgenic-tree derived products. Although it is unlikely that products from GM forest trees will be marketed in the next 10 to 15 years, information on the anticipated attitudes of consumers has to be taken into consideration by the developers and policy makers.

Keywords: Consumer Purchasing Behavior, Transgenic Forest Products, Transgenic Forest Trees

iForest 8 (5): 707-713 (2015) - doi: 10.3832/ifor1339-007
https://iforest.sisef.org/contents/?id=ifor1339-007

Research Articles: The combined effects of Pseudomonas fluorescens CECT 844 and the black truffle co-inoculation on Pinus nigra seedlings

Dominguez-Nuñez JA, Medina M, Berrocal-Lobo M, Anriquez A, Albanesi A — 2015-01-08

Dominguez-Nuñez JA, Medina M, Berrocal-Lobo M, Anriquez A, Albanesi A

THE COMBINED EFFECTS OF PSEUDOMONAS FLUORESCENS CECT 844 AND THE BLACK TRUFFLE CO-INOCULATION ON PINUS NIGRA SEEDLINGS

Abstract: The inoculation of forest seedlings with mycorrhizal fungi and rhizobacteria can improve the morphology and physiology of the seedlings and benefit the reforestation of Mediterranean areas and the reintroduction of mycorrhizal fungal inocula into these areas. Pinus nigra subsp. salzmannii,a forest component of the Mediterranean natural ecosystems, is currently used in the reforestation of Mediterranean regions. Its roots are able to form an ectomycorrhizal symbiosis with the Ascomycetes fungus Tuber melanosporum Vitt., the black truffle. The ecological, economic and social values of this ectomycorrhizal fungus is well known. Previously, we demonstrated that the inoculation of Pinus halepensis seedlings with Pseudomonas fluorescens CECT 844 rhizobacteria and the black truffle T. melanosporum improved the plant growth and N absorption of the seedlings. Furthermore, the addition of P. fluorescens CECT 844 doubled the rate of mycorrhization of T. melanosporum. In the present work, P. nigra seedlings were produced in a nursery under well-watered conditions. We studied the morphophysiological response of these seedlings to a combined T. melanosporum and/or a rhizobacteria P. fluorescens CECT 844 inoculation. Five months after inoculation, the growth parameters (seedling height, basal diameter, and shoot and root dry weight), mycorrhizal colonization, water parameters (osmotic potential at both full and zero turgor and modulus of elasticity), and the total contents and concentrations of N, P, and K in the seedlings roots and shoots were measured. The root growth potentials were subsequently estimated. The addition of P. fluorescens CECT 844 did not significantly improve the mycorrhizal colonization by T. melanosporum on P. nigra seedlings. Additionally, the P. fluorescens inoculation caused few significant improvements in the growth and water parameters. Moreover, apparently opposing effects were observed between the two inoculations regarding the seedlings P absorption. We discuss whether P. fluorescens CECT 844 could act as a Mycorrhizal Helper Bacterium (MHB) through different mechanisms depending on the environmental conditions.

Keywords: Rhizobacteria, Black Truffle, Mycorrhiza, Mycorrhiza Helper Bacteria

iForest 8 (5): 624-630 (2015) - doi: 10.3832/ifor1334-007
https://iforest.sisef.org/contents/?id=ifor1334-007

Short Communications: Effect of four levels of shade on survival, morphology and chlorophyll fluorescence of Nothofagus alessandrii container-grown seedlings

Santelices R, Espinoza S, Cabrera AM — 2015-01-08

Santelices R, Espinoza S, Cabrera AM

EFFECT OF FOUR LEVELS OF SHADE ON SURVIVAL, MORPHOLOGY AND CHLOROPHYLL FLUORESCENCE OF NOTHOFAGUS ALESSANDRII CONTAINER-GROWN SEEDLINGS

Abstract: Nothofagus alessandrii (ruil) is a threatened, endemic tree of the Mediterranean zone of Chile. As a result of past anthropogenic activities, its current cover has been reduced to only 314 hectares across several fragmented and degraded areas. Although activities to conserve and recover such forests have been developed, little is known about their propagation and nursery cultivation, since the plant’s quality is one of the most important factors for restoration and reforestation plans, re-vegetation, or forest enrichment. The success of restoration programs in these areas will require improvements in plant production, being important to test the shade effects on seedling survival and growth. This paper reports the results of testing for survival, morphological and chlorophyll fluorescence differences in N. alessandrii seedlings grown for approximately 32 weeks in unshaded conditions and under three different levels of shading (18%, 50%, and 80% shade). Morphological traits (stem height, root collar diameter, specific leaf area, shoot and root biomass, and quality indexes) and survival were measured. Chlorophyll fluorescence was also measured to analyze the shade tolerance of the species. Analysis showed significant differences for most traits as a consequence of the shade level. Seedlings exposed to 18% shade showed the highest total dry biomass, while those exposed to 80% shade showed the highest survival rate (92%). Chlorophyll fluorescence was high in the unshaded conditions and medium in the 18-50% shade. Morphological and chlorophyll fluorescence responses differed greatly among shade levels and corresponded with the degree of shade tolerance of the species.

Keywords: Seedling, Ruil, Early Growth, Shadow

iForest 8 (5): 638-641 (2015) - doi: 10.3832/ifor1321-007
https://iforest.sisef.org/contents/?id=ifor1321-007

Research Articles: Light acclimation of leaf gas exchange in two Tunisian cork oak populations from contrasting environmental conditions

Rzigui T, Khiari H, Abbes Z, Baaziz KB, Jaouadi I, Nasr Z — 2015-01-08

Rzigui T, Khiari H, Abbes Z, Baaziz KB, Jaouadi I, Nasr Z

LIGHT ACCLIMATION OF LEAF GAS EXCHANGE IN TWO TUNISIAN CORK OAK POPULATIONS FROM CONTRASTING ENVIRONMENTAL CONDITIONS

Abstract: Due to diverse environmental conditions, Mediterranean plant populations are exposed to a range of selective pressures that may lead to phenotypic plasticity and local adaptation. We examined the effect of light acclimation on photosynthetic capacity in two Quercus suber (L.) populations that are native to different ecological conditions. Low-light adapted seedlings from both populations were exposed to three light treatments: full sunlight (HL), medium light (ML, 43% sunlight) and low light (LL, 15% sunlight) for one month. Photosynthetic performance was monitored by measuring leaf gas exchange and chlorophyll fluorescence parameters. The light environment influences light-saturated carbon assimilation (Amax) in the leaves of the population inhabiting the hot and dry region (from Gaafour). In contrast, there was no significant difference in Amax between leaves grown in high light and low light from Feija (the population native to a cold and humid climate), which suggests an inability of the Feija population to adjust its photosynthesis to respond to higher irradiance. The inability of the Feija population to adjust its photosynthesis did not result from a light acclimation failure in terms of chlorophyll content and ratio compared with the Gaafour population. Instead, it seems to be the consequence of lower stomatal conductance in the Feija population at HL compared to Gaafour.

Keywords: Quercus suber L., Photosynthesis, Stomatal Conductance, Light, Acclimation

iForest 8 (5): 700-706 (2015) - doi: 10.3832/ifor1306-007
https://iforest.sisef.org/contents/?id=ifor1306-007

Technical Notes: Comparative analysis of students’ attitudes toward implementation of genetically modified trees in Serbia

Nonić M, Radojević U, Milovanović J, Perović M, Šijačić-Nikolić M — 2015-01-08

Nonić M, Radojević U, Milovanović J, Perović M, Šijačić-Nikolić M

COMPARATIVE ANALYSIS OF STUDENTS’ ATTITUDES TOWARD IMPLEMENTATION OF GENETICALLY MODIFIED TREES IN SERBIA

Abstract: Genetically-modified (GM) trees represent a new frontier in biotechnology, though many environmental concerns associated to the commercial use of GM trees and their products have been recently raised. In general, GM trees involve no safety issues related to human health, therefore public attitudes toward their commercial use should depend on environmental concerns or personal philosophical viewpoints, but also on educational level and background. To assess the relevance of the educational level and background on attitudes toward acceptance of commercial GM tree cultivation, a survey was conducted in January 2014 among 400 students from the Faculty of Forestry of the University of Belgrade and from the Faculty of Applied Ecology “Futura” at the University Singidunum (Belgrade). The aim was to determine whether different educational profiles and educational level significantly affect students’ attitudes toward GM trees. Results showed no significant differences in the responses among students from both faculties. All students showed a good knowledge of GM trees and agreed that different genetic modifications of forest trees would be very important for their country. Also, more than a half of students from both faculties would agree with commercial planting of GM trees and would purchase their final products. However, 70 to 90% of students from both faculties considered the hazards associated with the commercial use of GM trees as “serious hazard” or “slight hazard”. The implication of the above results are discussed.

Keywords: Genetic Modifications, Forest Trees, Biotechnology, Survey

iForest 8 (5): 714-718 (2015) - doi: 10.3832/ifor1305-007
https://iforest.sisef.org/contents/?id=ifor1305-007

Research Articles: Use of LIDAR-based digital terrain model and single tree segmentation data for optimal forest skid trail network

Sterenczak K, Moskalik T — 2014-12-22

Sterenczak K, Moskalik T

USE OF LIDAR-BASED DIGITAL TERRAIN MODEL AND SINGLE TREE SEGMENTATION DATA FOR OPTIMAL FOREST SKID TRAIL NETWORK

Abstract: The implementation of rational forest management that takes into consideration the requirements of sustainable forest development requires many decisions to be made, ranging from simple rules to extremely complex procedures. This is also true of logging operations, where the applied techniques and technologies should relate not only to economic aspects, but also be maximally adapted to the specific forest environment. One of the most important determinants of environmentally safe and effective logging work is forest accessibility through an appropriately planned road and skid trail network. This paper presents the possibilities of using the Airborne Laser Scanner (ALS) and Geographic Information System (GIS) to determine the optimal or near-optimal locations of forest skid trails. Choosing skid trails depends on the adopted logging method, existing road network, forest stand development phase, and terrain conditions. The process of optimization takes into account existing stand gaps to reduce the number of trees that must be removed for the network. Segments representing single trees and the Digital Terrain Model (DTM) served as inputs for the GIS analysis. The research was carried out in Scots pine stands. The obtained results show that the total length of skid trails, with 40 m distance between them, after optimization for traditional harvesting method decreased by 2%. For fully mechanized harvesting method, the skid trail network was decidedly denser (20 m) and an original length was reduced only by 0.06%. The results obtained confirmed the practical usefulness of the adopted procedures.

Keywords: Logging, Airborne Laser Scanner, Single Tree Detection, Digital Terrain Model, Optimal Forest Skid Trail Network

iForest 8 (5): 661-667 (2015) - doi: 10.3832/ifor1355-007
https://iforest.sisef.org/contents/?id=ifor1355-007

Research Articles: Gas exchange characteristics of the hybrid Azadirachta indica × Melia azedarach

Cheng X, He Z, Yu M, Yin Z — 2014-12-17

Cheng X, He Z, Yu M, Yin Z

GAS EXCHANGE CHARACTERISTICS OF THE HYBRID AZADIRACHTA INDICA × MELIA AZEDARACH

Abstract: The hybrid Azadirachta indica × Melia azedarach is a new plant variety that was obtained through somatic hybridization. The plant could grow normally in regions with an average annual temperature of 15 °C, and it had a higher concentration of active insecticidal substance in its seeds. Therefore, the hybrid will likely become a valuable new tree species in subtropical and warm temperate regions. However, the photosynthetic physiological characteristics of A. indica × M. azedarach remain unknown. The photosynthetic gas exchange of the hybrid at three different ages (one year old (AM1), three years old (AM3), and five years old (AM5)) were measured. The specific leaf mass per area (LMA), leaf N, leaf P, and leaf N/P of each tree sample were measured, and the photosynthetic N and P use efficiencies (PNUE and PPUE, respectively) were also calculated. The maximum leaf net photosynthetic rate Pa (based on area), Pm (based on mass), light saturation point (LSP), light compensation point (LCP), stomatal conductance (gs), and transpiration rate (Tr) of A. indica × M. azedarach decreased with increasing tree age, whereas the instantaneous water use efficiency (WUE) increased with age. The photosynthetic capacity showed no significant differences between AM3 and AM5 but was significantly higher in AM3 and AM5 when compared with AM1.The Pa, Pm, apparent quantum yield (AQY), LSP, gs, and Tr of A. indica × M. azedarach were significantly lower than that of the parental M. azedarach, whereas the dark respiration rate (Rd) and WUE were significantly higher than that of M. azedarach. A reduction in the maximal photosynthetic rate of A. indica × M. azedarach that was observed with increased age was primarily related to the increased LMA and the decline in leaf nitrogen (N) and leaf phosphorus (P) concentrations. Additionally, the decline in stomatal conductance (gs) was also an important factor leading to age-dependent reductions in the photosynthetic rate. These findings suggest that the tree’s age has a significant impact on A. indica × M. azedarach gas exchange during juvenile stages, and the photosynthetic capacity of the hybrid was significantly lower than that of the parental M. azedarach.

Keywords: Photosynthesis, Ontogeny, Stomatal Conductance, Leaf Nitrogen, Leaf Phosphorus, Leaf Mass Per Area

iForest 8 (4): 431-437 (2015) - doi: 10.3832/ifor1127-007
https://iforest.sisef.org/contents/?id=ifor1127-007

Research Articles: Arthropod diversity in pure oak forests of coppice origin in northern Thrace (Turkey)

2014-12-17

Keten A, Beskardes V, Kumbasli M, Makineci E, Zengin H, Özdemir E, Yilmaz E, Yilmaz HC, Caliskan S, Anderson JT

ARTHROPOD DIVERSITY IN PURE OAK FORESTS OF COPPICE ORIGIN IN NORTHERN THRACE (TURKEY)

Abstract: Oak (Quercus spp.) forests are among the most important forest types in Turkey. In the past, oak forests were managed through coppice clear-cutting, but in recent decades they have mostly been converted to high forest. This study was aimed at explaining how arthropod diversity is affected during conversion from coppice to high oak forest and during the early stages of coppice succession. We tested the hypothesis that arthropod richness, abundance and diversity in coppice oak sites varied according to stand age and a number of other forest characteristics. Arthropod communities were sampled in 50 plots using four different methods: pitfall traps, sweep nets, sticky cards and cloth shaking. A total of 13 084 individuals were collected and classified into 193 Recognizable Taxonomic Units (RTUs), with the most RTUs and the greatest number of specimens captured by sweep netting. We identified 17 taxa within RTU’s with more than 1% of the captured arthropods, which constituted 75% of the total specimens. The number of RTUs varied significantly according to trap type. Arthropod richness and Shannon-Wiener biodiversity index (H′) increased with elevation and precipitation. In young (1-40 yrs-old) and middle-aged (41-80 yrs) stands, arthropod biodiversity was not significantly affected by stand type, but slightly increased with diameter at breast height and tree height. Forest characteristics, such as the litter layer, understory and crown diameter, weakly influenced arthropod richness and abundance. Cluster analysis revealed that stand types and trap types differed taxonomically. Principal component analysis showed that stand types were clearly separated by the stand parameters measured. Insect families (Formicidae, Thripidae, Lygaeidae, Dolichopodidae, Luaxanidae, Cicadellidae and Ichneumonidae) could potentially be used as indicators of coppice oak conditions. As the coppice oak changes to mature forest, further studies are needed to better assess the relation between arthropods, forest types and structural characteristics of stands.

Keywords: Elevation, Quercus, Recognizable Taxonomic Units, Trap Types, Stand Types, Stand Characteristics

iForest 8 (5): 615-623 (2015) - doi: 10.3832/ifor1318-007
https://iforest.sisef.org/contents/?id=ifor1318-007

Research Articles: Effect of silver nanoparticles on hardness in medium-density fiberboard (MDF)

Taghiyari HR, Norton J — 2014-12-17

Taghiyari HR, Norton J

EFFECT OF SILVER NANOPARTICLES ON HARDNESS IN MEDIUM-DENSITY FIBERBOARD (MDF)

Abstract: Effect of silver nanoparticles on hardness in medium-density fiberboard (MDF) was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL kg-1, based on the dry weight of wood fibers; the results were then compared with the control panels. The size range of silver nanoparticles was 30-80 nm. Composite mats were hot-pressed for 6, 8, and 10 min. Results showed that the uniform and even dispersion of nanoparticles throughout the MDF-matrix significantly contributed to an increase in the hardness at lower hot-press time of 6 min. In the longer hot-press times, however, over-heating of the mat resulted in significant a decrease of hardness values. Significant high correlation was observed between water absorption and thickness swelling.

Keywords: Composite Board, Heat Transferring Property, Metal Nanoparticles, Nanosilver, Thermal Conductivity Coefficient, Wood Fiber

iForest 8 (5): 677-680 (2015) - doi: 10.3832/ifor1188-007
https://iforest.sisef.org/contents/?id=ifor1188-007

Research Articles: Physical-mechanical properties and bonding quality of heat treated poplar (I-214 clone) and ceiba plywood

Goli G, Cremonini C, Negro F, Zanuttini R, Fioravanti M — 2014-12-17

Goli G, Cremonini C, Negro F, Zanuttini R, Fioravanti M

PHYSICAL-MECHANICAL PROPERTIES AND BONDING QUALITY OF HEAT TREATED POPLAR (I-214 CLONE) AND CEIBA PLYWOOD

Abstract: The present paper investigates the physical and mechanical modifications of both poplar (I-214 clone) and ceiba veneers and plywood after heat treatments of different intensities (5 and 7 % of dry mass losses). Plywood panels were glued before and after heat treatment with urea-formaldehyde (UF) and melamine-urea-formaldehyde (MUF) resins. In order to assess the treatments’ effects on both the wood and the glues, the dry mass, the density, the bending strength, the Young’s modulus and the bonding quality were measured before and after heat treatment. The results of the different treatments were compared as well. Results showed that the loss in cell wall polymers due to the heat treatment caused a significant reduction of the equilibrium moisture content of the samples. From a mechanical point of view the treatment resulted in an important reduction of strength and in a small reduction of stiffness. Bonding quality as well as mechanical properties were widely affected by the heat treatment. The different intensities of the treatments (the treatment range was up to 5% and 7% of dry mass loss) did not show significant differences for most of the features assessed. The mechanical performance as well as the bonding quality of treated samples suggested that veneers should be glued after heat treatment. Apparent cohesive wood failure showed that different degradations affect wood and glues with a prominent effect on the glues for UF resins and a prominent effect on the wood for MUF resins.

Keywords: Heat Treatment, Poplar, Ceiba, Plywood, Bonding Quality, Physical-mechanical Properties

iForest 8 (5): 687-692 (2015) - doi: 10.3832/ifor1276-007
https://iforest.sisef.org/contents/?id=ifor1276-007

Research Articles: Genetic variation and heritability estimates of Ulmus minor and Ulmus pumila hybrids for budburst, growth and tolerance to Ophiostoma novo-ulmi

Solla A, López-Almansa JC, Martín JA, Gil L — 2014-12-15

Solla A, López-Almansa JC, Martín JA, Gil L

GENETIC VARIATION AND HERITABILITY ESTIMATES OF ULMUS MINOR AND ULMUS PUMILA HYBRIDS FOR BUDBURST, GROWTH AND TOLERANCE TO OPHIOSTOMA NOVO-ULMI

Abstract: Seedlings obtained by crossing Ulmus minor and U. minor × U. pumila clones were assessed for flowering, bark beetle damage, vegetative budburst, height growth and resistance to Ophiostoma novo-ulmi. Ramets and open pollinated seedlings obtained from the parent trees were assessed for the same traits. Most progenies had similar traits to their parents, but some presented heterosis in annual growth or resistance to O. novo-ulmi. Leaf wilting was significantly lower in progenies with U. minor × U. pumila rather than U. minor as female parent (21.5 and 30.6%, respectively; P<0.05). Resistance to O. novo-ulmi increased significantly as a function of increased amounts of U. pumila germplasm from the female parent, suggesting that resistance to Dutch elm disease is primarily transmitted from the mother. Budburst occurred earlier in seedlings with low rather than high growth rates (P=0.0007) and percentage of wilting was negatively related to early budburst (P<0.0001). Other phenotypic relations included percentage of flowering trees and annual height growth (rp=0.44; P=0.0042), percentage of flowering trees and vegetative budburst (rp=-0.53; P=0.0004) and percentage of beetle-affected trees and annual height growth (rp=0.60; P<0.0001). Heritability estimates obtained from the regression and variance components methods ranged from 0.06 ± 0.04 to 0.64 ± 0.18, 0.10 ± 0.05 to 0.69 ± 0.17, and 0.13 ± 0.32 to 0.71 ± 0.22 for budburst, growth and tolerance to O. novo-ulmi, respectively. Broad- and narrow-sense heritability values were higher when estimated 60 days post inoculation (dpi) than 15, 30 or 120 dpi. Heritability estimates and genetic gains reported indicate a high degree of additive genetic control and show the effectiveness of selection for Dutch elm disease resistance and rapid tree growth.

Keywords: Quantitative Genetics, Tree Breeding, Invasive Pathogen, Inheritance, Additive Genetic Variance, Non-additive Genetic Variance, Heterosis, Genetic Gain

iForest 8 (4): 422-430 (2015) - doi: 10.3832/ifor1227-007
https://iforest.sisef.org/contents/?id=ifor1227-007

Research Articles: Links between phenology and ecophysiology in a European beech forest

2014-12-15

Urban J, Bednárová E, Plichta R, Gryc V, Vavrčík H, Hacura J, Fajstavr M, Kučera J

LINKS BETWEEN PHENOLOGY AND ECOPHYSIOLOGY IN A EUROPEAN BEECH FOREST

Abstract: Over the course of a year, tree physiological processes are not only directly affected by environmental conditions, but also by the tree’s own phenological stages. At the same time, phenological stages should, to a certain degree, reflect tree physiology. However, we have rather poor knowledge of the details of the interplay between phenology and ecophysiology. The objective of this study was to develop a better understanding of the links between phenology and ecophysiology. We investigated the degree to which various physiological processes are synchronized both with each other and with phenology and what information related to phenology can be obtained from instrumental ecophysiological measurements. Phenological observations, along with measurements of transmittance of photosynthetically active radiation (PAR), stem volume changes, sap flow and xylogenesis were conducted in a 45-year old European beech (Fagus sylvatica) stand in the Czech Republic. Results indicated that ecophysiology was tightly related with the phenological stage of the tree. Early spring phenological stages were closely linked with the beginning of cambial activity and the onset of sap flow, i.e., the first leaves were produced simultaneously with the beginning of stem radial growth. The highest xylem growth rates occurred in June, simultaneously with the highest sap flow rates. Cambial activity ceased with the onset of summer leaf coloring at the end of July, at the same time as the permanent decrease in sap flow rate. The end of cell wall maturation was linked to the onset of autumn leaf coloring. We conclude that instrumental measurements of tree and stand ecophysiology provided additional information better specifying the onset of particular phenostages. In our case, twelve permanently located sensors used to measure PAR transmittance captured leaf area development with acceptable accuracy, thus limiting the need for frequent visits to the forest site in the spring and autumn. Moreover, data from dendrometers showed linkages to bud break and the onset of leaf coloring. Therefore, ecophysiological measurements increased the effectiveness and accuracy of phenological observations and provided additional information about tree development in particular external conditions.

Keywords: Phenology, Ecophysiology, Sap Flow, Xylogenesis, Photosynthetically Active Radiation, Dendrometers

iForest 8 (4): 438-447 (2015) - doi: 10.3832/ifor1307-007
https://iforest.sisef.org/contents/?id=ifor1307-007

Research Articles: Size and age: intrinsic confounding factors affecting the responses to a water deficit in black spruce seedlings

Walsh D, Rossi S, Lord D — 2014-12-09

Walsh D, Rossi S, Lord D

SIZE AND AGE: INTRINSIC CONFOUNDING FACTORS AFFECTING THE RESPONSES TO A WATER DEFICIT IN BLACK SPRUCE SEEDLINGS

Abstract: The resistance to stress of seedlings during the initial phases after planting is fundamental for assuring fast establishment and long-term survival of artificial regeneration. Although needing less storage space and handling during their production and planting, small seedlings are considered to be less efficient in terms of water uptake and more sensitive to a water deficit than bigger seedlings. The responses to a water deficit produced by a suspension of irrigation for 14 days were assessed in black spruce (Picea mariana [Mill.] BSP) seedlings of different sizes, with height ranging between 13 and 71 cm. Seedlings growing in containers with cavity volumes of 25, 50, 110, 350 cm3 were tested. During the treatment, the seedlings attained Ψpd of between -1.71 and -2.28 MPa, indicating that a severe water stress was reached. Smaller seedlings exhibited similar or higher water potential and gas exchanges than bigger seedlings both during and after the treatment. Although root biomass was higher in bigger seedlings, the growth rates of roots were similar between seedling sizes and were not affected by the water stress. The initial hypothesis that small seedlings are more sensitive to water stress was rejected. The delayed stomatal closure and higher CO2 assimilation rate of smaller seedlings during the treatment could be attributed to a lower shoot:root ratio and greater ability of roots to sustain the evaporative needs of needles, which could attain higher performances in carbon assimilation. The potential effects of confounding factors such as age and pre-treatment preventing to identify the main factor affecting drought tolerance in black spruce seedlings were discussed.

Keywords: Artificial Regeneration, Boreal Forest, Containerized Plants, Planting, Water Stress

iForest 8 (4): 401-409 (2015) - doi: 10.3832/ifor1412-007
https://iforest.sisef.org/contents/?id=ifor1412-007

Technical Reports: Nursery practices increase seedling performance on nutrient-poor soils in Swietenia humilis

2014-12-09

Basave Villalobos E, Alcalá Cetina VM, López López MA, Aldrete A, Del Valle Paniagua DH

NURSERY PRACTICES INCREASE SEEDLING PERFORMANCE ON NUTRIENT-POOR SOILS IN SWIETENIA HUMILIS

Abstract: Swietenia humilis is a valued tree species for its high-quality wood, among other commercial interests. Attempts to plant the species in southwest Mexico have often failed due to poor quality seedlings combined with low soil fertility and dry environments. Nursery top-pruning and fertilization are practices previously reported to improve seedling quality, and facilitate rapid establishment under poor site conditions. In the present study, the effects of three top-pruning intensities (0%, 25%, and 50%), and two fertilizer regimes (traditional and exponential) on several S. humilis seedling morphological and physiological indices were tested in the nursery, and a quality test trial on nutrient-poor soils was conducted. Significant interactions between the above two treatments were not detected. Top pruning at 25% and 50% intensity did not improve S. humilis seedling quality. However, exponential nutrient supply exhibited favorable effects on seedling growth. Results of the quality test trial revealed exponential fertilization promoted satisfactory seedling performance when low nutrient availability was a limiting factor.

Keywords: Caobilla, Seedling Quality, Top Pruning, Exponential Fertilization

iForest 8 (4): 552-557 (2015) - doi: 10.3832/ifor1179-007
https://iforest.sisef.org/contents/?id=ifor1179-007

Technical Reports: De novo adventitious root formations in mini-cuttings of Azadirachta indica in response to different rooting media and auxin treatments

Gehlot A, Gupta RK, Arya ID, Arya S, Tripathi A — 2014-12-09

Gehlot A, Gupta RK, Arya ID, Arya S, Tripathi A

DE NOVO ADVENTITIOUS ROOT FORMATIONS IN MINI-CUTTINGS OF AZADIRACHTA INDICA IN RESPONSE TO DIFFERENT ROOTING MEDIA AND AUXIN TREATMENTS

Abstract: Neem (Azadirachta indica A. Juss) is a multipurpose Indian tree important to local economy. Conservation of the genetic resources of neem is essential for the adaptability of this tree species to projected climate change impacts. Here, the effect of type and concentration of auxins in different rooting media on adventitious root formation (ARF) in mini-cuttings of Azadirachta indica is depicted. Three different rooting media (i.e., sand, vermiculite and soil) were used, and the experiment was established using three types of auxin (IBA, IAA and NAA) and 6 concentration treatment combinations (100, 250, 500, 750, 1000 and 1500 mg l-1), in a complete randomized block design (CRBD). Significant effects of different auxin types, concentration treatments and rooting media on adventitious root formation of neem mini-cuttings were observed. Mini-cuttings were assessed for rooting percentage, number of roots, root length and number of leaves. IBA resulted in higher rooting percentage (90%), number of roots (149.56), root length (14.83 cm) and number of leaves per rooted mini-cuttings (12.78), when growing in sand. The determination of proper rooting protocols and the use of mini-cuttings were proved important for improving mass propagation of A. indica.

Keywords: Mini-cuttings, Adventitious Root Formation (ARF), Azadirachta Indica, Auxin

iForest 8 (4): 558-564 (2015) - doi: 10.3832/ifor1189-007
https://iforest.sisef.org/contents/?id=ifor1189-007

Research Articles: Soil respiration along an altitudinal gradient in a subalpine secondary forest in China

Luo S, Liu G, Li Z, Hu C, Gong L, Wang M, Hu H — 2014-12-01

Luo S, Liu G, Li Z, Hu C, Gong L, Wang M, Hu H

SOIL RESPIRATION ALONG AN ALTITUDINAL GRADIENT IN A SUBALPINE SECONDARY FOREST IN CHINA

Abstract: The subalpine forest ecosystems in the Miyaluo Forest District in western Sichuan (China) could be very sensitive to global climate change, with important consequences for the regional carbon (C) balance. In a birch secondary forest in this area, we measured plots with (Control) and without (No Litter) leaf litter to explore variation in soil respiration and its relationship with environmental factors along an altitudinal gradient, and to quantify the litter contribution to soil respiration. Soil respiration rate decreased with elevation. The average of soil respiration rates along the elevation gradient during the measurement period was 2.83 ± 0.14 μmol CO2 m-2 s-1 in the Control treatment and 2.35 ± 0.16 μmol CO2 m-2 s-1 in the No Litter treatment, with an average proportion of litter layer contribution to soil respiration of 17%. A significant linear relationship between soil respiration and soil temperature along the altitudinal gradient was found, while soil respiration was not significantly correlated with soil water content in both treatments. Soil temperature accounted for 94.9% and 95.6% of the total variation in soil respiration in Control and No Litter treatments, respectively. At altitudes of 2910 m, 3135 m, 3300 m and 3492 m a.s.l., soil respiration had a significant exponential relationship with soil temperature (p<0.05), but it was not significantly correlated with soil water content in both treatments (p>0.05). Soil temperature accounted for more than 92% and 81% of the total variation in soil respiration in Control and No Litter treatments, respectively, at all altitudes except at 3135 m a.s.l. Our results suggest that the expected temperature increases by global warming might enhance soil respiration in the birch secondary forest.

Keywords: Birch Secondary Forest, Soil Respiration, Soil Temperature, Soil Water Content, Litter

iForest 8 (4): 526-532 (2015) - doi: 10.3832/ifor0895-007
https://iforest.sisef.org/contents/?id=ifor0895-007

Research Articles: Does higher owner participation increase conflicts over common land? An analysis of communal forests in Galicia (Spain)

Marey-Pérez MF, Díaz-Varela E, Calvo-González A — 2014-12-01

Marey-Pérez MF, Díaz-Varela E, Calvo-González A

DOES HIGHER OWNER PARTICIPATION INCREASE CONFLICTS OVER COMMON LAND? AN ANALYSIS OF COMMUNAL FORESTS IN GALICIA (SPAIN)

Abstract: Communal forests or Montes Vecinales en Mano Común (MVMC) are a type of private collective land in Galicia (NW of Spain) that amounts to approximately one third of its forest land. There has been a series of changes in MVMC ownership and management throughout the 20th century. Uncertainty about ownership, changes in population and the presence of the Forestry Authority bring about deficiencies in management and increases conflict. This paper analyses MVMC management in 1.731 parishes in Galicia. The digital records of local and regional newspapers were used to compile a database consisting of 2.734 news reports related to MVMC issues. The results of hypothesis testing and of spatial analysis show that population, agricultural activity and land use affect management and conflict rates. This paper discusses how active management and conflict are complementary models, and how the presence or absence of one or the other is a determining factor in the situation of each parish. It concludes that it is necessary to implement management models and strategies to minimise conflict and increase active management for sustainable forest development in the region.

Keywords: Commonly-owned Private Property, Communal Forests, Media, Social Participation, Management Models

iForest 8 (4): 533-543 (2015) - doi: 10.3832/ifor1060-008
https://iforest.sisef.org/contents/?id=ifor1060-008

Research Articles: Modeling of early stage litter decomposition in Mediterranean mixed forests: functional aspects affected by local climate

Vitale M, Savi F, Baldantoni D, Attorre F — 2014-11-18

Vitale M, Savi F, Baldantoni D, Attorre F

MODELING OF EARLY STAGE LITTER DECOMPOSITION IN MEDITERRANEAN MIXED FORESTS: FUNCTIONAL ASPECTS AFFECTED BY LOCAL CLIMATE

Abstract: Litter decomposition is an important process occurring in forest ecosystems, where it affects the carbon balance as a whole. In Mediterranean area, seasonal changes and climate variations associated to latitude and structural characteristics of forest stands have a real effect on decomposition rates. Current leaf litter decomposition models are frequently too general to represent local climate variations in Mediterranean forests. We developed a new dynamic semi-empirical-based model, which simulated the early stage of decomposition of leaf litter based on local climate conditions and few operational parameters. Leaf litter was divided in two components, settled on different carbon compound concentrations. The effects of temperature and moisture were characterized by specific equations and the decomposition rates were time-depending functions. Equations were calibrated by the best fitting procedure performed on field data obtained by the litterbag method followed in mixed deciduous forests in central Apennines (Italy). Model validation showed an excellent correlation between observed and predicted values (R2 between 0.89 and 0.95), predicting thus differences in decomposition rates among different local climates. The simple structure of the model and the satisfactory reliability of outputs are important features for a practical alternative to other CO2 release evaluation methods applied to forest ecosystems.

Keywords: Decomposition Rate, Litterbags, Mediterranean Climate, Semi-empirical Models

iForest 8 (4): 517-525 (2015) - doi: 10.3832/ifor1202-007
https://iforest.sisef.org/contents/?id=ifor1202-007

Short Communications: Differentiation of Populus species by chloroplast SNP markers for barcoding and breeding approaches

Schroeder H, Fladung M — 2014-11-13

Schroeder H, Fladung M

DIFFERENTIATION OF POPULUS SPECIES BY CHLOROPLAST SNP MARKERS FOR BARCODING AND BREEDING APPROACHES

Abstract: About 30 species within the genus Populus are classified in six sections. Several species belonging to different sections are cross-compatible, resulting in a high number of naturally occurring interspecies hybrids. Additionally, an even higher number of hybrids has been produced in huge breeding programs during the last 100 years. Hence, determination of poplar species used for production of “multi-species-hybrids” is often difficult and, therefore, a challenge in developing molecular markers for species identification. Fourteen out of the 30 poplar species known are used more or less regularly for production of artificial hybrids and clones. In this study, we focused on over 20 chloroplast regions, and we tested 23 primer combinations already established for “Barcoding” approaches and seventeen new primer combinations designed earlier for the applicability to differentiate fourteen poplar species. In contrast to the self-designed primer combinations with a much higher amplification success, only about half of the established barcoding primer combinations yielded amplification products. In total, for eleven of the fourteen used poplar species we found species-specific SNPs or Indels. Most of the variation was found in intergenic spacers. In order to design an inexpensive and fast method of species identification, we developed PCR-RFLPs applicable for seven of the species-specific SNPs. Altogether there is high variation in chloroplast intergenic spacers within the genus Populus, illustrated by the fact that four primer combinations are needed to differentiate eleven species. Thus, we support the suggestion of using multi-locus combinations in barcoding analyses.

Keywords: Chloroplast Genome, SNPs, Indel, Barcoding, Intergenic Spacer

iForest 8 (4): 544-546 (2015) - doi: 10.3832/ifor1326-007
https://iforest.sisef.org/contents/?id=ifor1326-007

Research Articles: Growth patterns of Scots pine (Pinus sylvestris L.) under the current regional pollution load in Lithuania

Augustaitis A, Augustaitiene I, Mozgeris G, Juknys R, Vitas A, Jasinevičiene D — 2014-11-12

Augustaitis A, Augustaitiene I, Mozgeris G, Juknys R, Vitas A, Jasinevičiene D

GROWTH PATTERNS OF SCOTS PINE (PINUS SYLVESTRIS L.) UNDER THE CURRENT REGIONAL POLLUTION LOAD IN LITHUANIA

Abstract: The belief that trees have begun growing more rapidly in recent years was examined in Scots pine (Pinus sylvestris L.) forests, a dominant forest type in Lithuania. The largest, pre-dominant pine trees, with a diameter at breast height exceeding 50 cm, were selected for analysis in this study; these were growing in three experimental overly-mature stands located in different parts of Lithuania (north-eastern, western and seaside). We hypothesized that if the annual tree increment has increased in recent years, then the largest trees in the stand should regularly demonstrate this characteristic first of all. The data collected for this study confirmed that since the 1980 growing season the annual increment of the pine trees analysed here has increased. The causes of this rapid growth were higher air temperatures during the dormant period and, to a lesser extent, the higher temperatures from May through August. The effect of precipitation was negligible. A 30-year long data set on acidifying pollutants allowed us to detect significant effect of reduced SO2 concentration and sulphur deposition as well as gradually increased ammonia deposition on the increased annual basal area increment of pine trees over the last 30 year long period. Multiple regression analysis indicated that meteorological parameters can explain up to 50% of the observed increase in the growth rate of Scots pine in Lithuania; meanwhile the presence of acidifying species can account for an additional 30%. However, the pollution data set (20-30 years) was insufficiently long to be compared with the meteorological data. Therefore we were unable to distinguish whether the recent decrease in pollution or global warming resulted in the increases in tree growth rates more significant.

Keywords: Scots Pine Growth, Pre-dominant Trees, Climate Change, Acidifying Species

iForest 8 (4): 509-516 (2015) - doi: 10.3832/ifor1267-007
https://iforest.sisef.org/contents/?id=ifor1267-007

Research Articles: Effects of substrate and ectomycorrhizal inoculation on the development of two-years-old container-grown Norway spruce (Picea abies Karst.) seedlings

Repáč I, Balanda M, Vencurik J, Kmet J, Krajmerová D, Paule L — 2014-11-10

Repáč I, Balanda M, Vencurik J, Kmet J, Krajmerová D, Paule L

EFFECTS OF SUBSTRATE AND ECTOMYCORRHIZAL INOCULATION ON THE DEVELOPMENT OF TWO-YEARS-OLD CONTAINER-GROWN NORWAY SPRUCE (PICEA ABIES KARST.) SEEDLINGS

Abstract: The objective of this study was to test the effects of selected peat growth substrates (Agro CS, Gramoflor and Durpeta) and inoculation with commercial ectomycorrhizal inocula (Ectovit and Mycorrhizaroots) on growth, ectomycorrhiza formation, needle nutrients concentration and several physiological parameters of two-years-old containerized Norway spruce seedlings cultivated under standard nursery conditions. The selected substrates differed in origin, composition and nutrient content: Agro CS and Gramoflor were mixtures of various peat types and components with added nutrients, while Durpeta was non-enriched pure peat. Growth parameters of seedlings cultivated in enriched substrates were significantly higher than those grown on the non-enriched substrate. Significant interactions were found between substrate and inoculation treatments. Inoculation with Ectovit stimulated seedling growth in non-enriched substrate but had no effect on seedling parameters in the enriched substrates, and a negative effect on aboveground biomass in Gramoflor. Mycorrhizaroots inoculum significantly decreased shoot to root dry weight ratio, but had no other effect on seedling development. ECM colonization rate of seedlings ranged from 73 to 80%, with no significant effects of the ECM inoculum or growth substrate. DNA analysis revealed a low species diversity of ECM fungi on seedling roots, with a pronounced dominance of the soil-borne ECM species Thelephora terrestris Fr. Chemical analysis of needles and measurement of chlorophyll a fluorescence showed similar trends as seedling growth. Values of chlorophyll a fluorescence parameters and needle N, P, K, Ca and Mg concentrations were higher in both enriched substrates. Ectovit increased (though not significantly) chlorophyll a fluorescence in needles as compared to Mycorrhizaroots- and non-inoculated seedlings, as well as nutrient-uptake (mainly K) in the non-enriched substrate. Our results suggest the importance of the origin and composition of peat-based substrates on the development of container-grown Norway spruce seedlings, while the observed positive effect of the commercial ECM inoculum Ectovit was more probably caused by its physical and chemical properties rather than by its efficiency in promoting ECM fungi symbiosis. The enriched substrates tested appear to be suitable for production of spruce seedlings of acceptable size for outplanting within two growing seasons.

Keywords: Peat Substrate, Ectomycorrhizal Inoculation, Norway Spruce, Container-grown Seedlings, Nutrition, Chlorophyll a Fluorescence, DNA Analysis

iForest 8 (4): 487-496 (2015) - doi: 10.3832/ifor1291-007
https://iforest.sisef.org/contents/?id=ifor1291-007

Research Articles: Ecological and anthropogenic drivers of Calabrian pine (Pinus nigra J.F. Arn. ssp. laricio (Poiret) Maire) distribution in the Sila mountain range

Nicolaci A, Travaglini D, Menguzzato G, Nocentini S, Veltri A, Iovino F — 2014-11-10

Nicolaci A, Travaglini D, Menguzzato G, Nocentini S, Veltri A, Iovino F

ECOLOGICAL AND ANTHROPOGENIC DRIVERS OF CALABRIAN PINE (PINUS NIGRA J.F. ARN. SSP. LARICIO (POIRET) MAIRE) DISTRIBUTION IN THE SILA MOUNTAIN RANGE

Abstract: The most well-known and vast Calabrian pine forests are in the Sila mountain range, in southern Italy. In this paper, we analysed the present-day distribution of Calabrian pine in the Sila mountain range and compared it with forest maps from 1935 to evaluate changes in land use. We then identified the ecological variables, together with anthropogenic factors such as management and other disturbing factors like fires, which induced changes in Calabrian pine forests. In 2006, the area covered by Calabrian pine forests and mixed Calabrian pine-beech forests was 36.100 ha and 20.221 ha, respectively. Overall, pine forest area increased by 38% between 1935 and 2006. Calabrian pine distribution in the Sila mountain range is driven by the ecological variables bioclimate, soil, and elevation, and by anthropogenic factors; from these results, 4 potential dynamics are detailed. In the face of changes both in management and in environmental factors, such as expected climate change, we provide a knowledge base for sustainable management and conservation of this important mountain forest habitat.

Keywords: Ecological Factors, Forest Management, Land Use Changes, Forest Dynamics

iForest 8 (4): 497-508 (2015) - doi: 10.3832/ifor1041-007
https://iforest.sisef.org/contents/?id=ifor1041-007

Research Articles: Advantages of the point-intercept method for assessing functional diversity in semi-arid areas

Nunes A, Tápia S, Pinho P, Correia O, Branquinho C — 2014-10-31

Nunes A, Tápia S, Pinho P, Correia O, Branquinho C

ADVANTAGES OF THE POINT-INTERCEPT METHOD FOR ASSESSING FUNCTIONAL DIVERSITY IN SEMI-ARID AREAS

Abstract: Semi-arid areas are particularly susceptible to the loss of biodiversity as a consequence of global change. Species functional traits are key drivers of functioning and resilience of ecosystems, thus monitoring of functional trait diversity is urgently needed. The assessment of functional diversity requires the quantification of species and/or their traits in the field, though there is no consensus on the best plant-sampling method to be used. The aim of this study was to compare the performance of the point-intercept (PT) method with two area-based approaches, the modified-Whittaker (MW) and Dengler (DE) methods, to assess functional diversity in semi-arid areas. The herbaceous community of a savanna-like Mediterranean woodland was surveyed at the two extremes of a regional precipitation gradient (dry to wet). Efficiency in the quantification of species/ traits, precision of cover estimates, and their effect on functional diversity metrics computed for eight functional traits were compared. Results showed that the examined methods differed in their efficiency in quantifying species/traits in both sites. With the DE method, fewer species were detected than with the MW and PT methods, which yielded similar values. The PT method had a higher precision in the quantification of both dominant and non-dominant species/traits. It also had a higher community evenness, mainly in the wet location, which allowed the analysis of a greater number of species/traits within the 80% “dominance” threshold (i.e., species representing 80% of the relative cover of community), a critical aspect of functional diversity assessments. In addition, the PT method yielded higher estimates for multi-trait functional evenness, as well as different estimates (either higher or lower than MW and DE) of single-trait community weighted means (for N-fixing ability and flowering onset), functional dispersion (for N-fixing ability and specific leaf area), and functional evenness (for height and flowering onset). In spite of the observed differences among methods in the assessment of functional diversity, the PT approach demonstrated important advantages in the non-destructive, fine-scale monitoring of semi-arid areas, where “less dominant” species may play a critical role.

Keywords: Dengler Method, Drylands, Field Plant Sampling, Functional Structure, Functional Diversity, Grassland, Modified-Whittaker, Point-intercept Method

iForest 8 (4): 471-479 (2015) - doi: 10.3832/ifor1261-007
https://iforest.sisef.org/contents/?id=ifor1261-007

Research Articles: Role of forest cover, land use change and climate change on water resources in Marmara basin of Turkey

Pamukcu P, Serengil Y, Yurtseven I — 2014-10-31

Pamukcu P, Serengil Y, Yurtseven I

ROLE OF FOREST COVER, LAND USE CHANGE AND CLIMATE CHANGE ON WATER RESOURCES IN MARMARA BASIN OF TURKEY

Abstract: We evaluated the influence of climate change and land use changes on water resources in the Marmara Region (Turkey) using the watershed runoff coefficients (RC) and trend analysis techniques on long-term (30 years) hydrometerological data. Land use changes in the selected sub-watersheds were obtained from CORINE land use maps for 1990, 2000, and 2006, and interpolated for annual changes. Forty-two land use types of Corine maps were grouped in four basic classes (forests, rangelands, farmlands, settlements). Principal component analysis was used to identify the most relevant land use types influencing RC since 1990. Results showed that changes in the proportion of forestlands, farmlands, and rangelands significantly affected RC. Settlements also affected RC, but to a lesser extent. RCs values for the different land use types were optimized on a subset of 28 out of the 48 sub-watersheds analyzed by minimizing the sum of least-square errors, while the remaining subset of 20 sub-watersheds was used to validate the models obtained. The R2 values for optimization and validation were 0.80 and 0.70, respectively. RCs of all watersheds were estimated for the period 1990-2012. Long-term trends in mean annual precipitation and temperature were examined by Mann-Kendall test based on time series from eight weather stations with records since 1930s. Contrasting significant trends of variation through time were found only for two stations as for precipitation, and for one station as for temperature. Overall, our results suggest that significant land use changes occurred in the region since 1990, but only slight variations in climate parameters. However, we conclude that neither land use changes nor the variation in climate parameters caused statistically significant effects on RCs and water resources.

Keywords: Climate Change, Land Use Change, Water Resources, Runoff Coefficient

iForest 8 (4): 480-486 (2015) - doi: 10.3832/ifor1242-007
https://iforest.sisef.org/contents/?id=ifor1242-007

Research Articles: The Habitat-Trees experiment: using exotic tree species as new microhabitats for the native fauna

Zapponi L, Minari E, Longo L, Toni I, Mason F, Campanaro A — 2014-10-22

Zapponi L, Minari E, Longo L, Toni I, Mason F, Campanaro A

THE HABITAT-TREES EXPERIMENT: USING EXOTIC TREE SPECIES AS NEW MICROHABITATS FOR THE NATIVE FAUNA

Abstract: The cavities that develop in veteran trees represent a key microhabitat for forest biodiversity and especially for secondary cavity nesters that rely on this resource for shelter. Since the availability of deadwood, veteran and hollow trees is threatened by forest management, we explored the possibility of increasing the presence of these scarce resources. To increase the abundance of dead wood-microhabitats, 113 trees of the hybrid planes (Platanus x acerifolia) were converted into new living structures, the Habitat Trees (HT). To investigate the potential of this resource on the native avian fauna, six types of cavities were designed according to the size requirements of the target bird species. The temporal evolution of the cavities and their use by birds were then studied for eight years. The artificial cavities generally did not compromise growth and stability of the trees, and the majority remained alive. These hollows offered better thermal insulation compared to traditional nest-boxes and natural cavities. Their use increased during the first three years, reaching the 80%. In the following years, the use declined (probably because of the increase of rot and displacement of the lids).This highlights the need of management to maintain their suitability through time. Our results suggest a possible cost-effective alternative use of alien tree species, which should be included in management actions to compensate the shortage of hollow trees in managed forests.

Keywords: Birds, Deadwood, Exotic Species, Forest Management, LIFE Project, Saproxylic Organisms

iForest 8 (4): 464-470 (2015) - doi: 10.3832/ifor1281-007
https://iforest.sisef.org/contents/?id=ifor1281-007

Research Articles: Influence of tree density on climate-growth relationships in a Pinus pinaster Ait. forest in the northern mountains of Sardinia (Italy)

Mazza G, Cutini A, Manetti MC — 2014-10-19

Mazza G, Cutini A, Manetti MC

INFLUENCE OF TREE DENSITY ON CLIMATE-GROWTH RELATIONSHIPS IN A PINUS PINASTER AIT. FOREST IN THE NORTHERN MOUNTAINS OF SARDINIA (ITALY)

Abstract: In view of the projected increases in the frequency and duration of drought events in the Mediterranean basin, a better understanding how differences in stand structure influence climate-growth relationships can improve and drive the conservation and management strategies for marginal forests in mountain areas. In this study, we examined the intra-annual variability of growth patterns and responses to climate of two maritime pine (Pinus pinaster Ait.) stands growing at contrasting tree densities at low elevation in northern Sardinia. A dendroclimatic analysis was used to assess the climate-growth relationships of these trees on monthly, seasonal and annual scales. The late spring and summer precipitations of the current year appeared to be the crucial climatic driver that encouraged the radial growth of the species in this mountain stand. However, summer drought was the primary climate constraint, exerting negative effects on P. pinaster growth. Summer Palmer drought severity index showed contrasting influence on latewood growth responses to drought conditions related to stand density, remaining significant also during the autumn months in the stand with the highest tree density. Our findings indicate that stands growing at high tree densities may experience more prolonged water shortages, especially during the late summer and early autumn months. Additionally, since the early 1980s, as precipitation has decreased, the influence of previous rainy years on radial growth has been highly significant in the stand with the lowest tree density. This result might suggests that these trees are able to utilize a greater amount of water reaching deeper soil horizons stored due to the previous rainy years, especially during periods of low precipitation.

Keywords: Pinus pinaster, Tree Rings, Stand Density, Climate-growth Relationships, Drought

iForest 8 (4): 456-463 (2015) - doi: 10.3832/ifor1190-007
https://iforest.sisef.org/contents/?id=ifor1190-007

Research Articles: Use of terrestrial laser scanning to evaluate the spatial distribution of soil disturbance by skidding operations

Koren M, Slančík M, Suchomel J, Dubina J — 2014-10-08

Koren M, Slančík M, Suchomel J, Dubina J

USE OF TERRESTRIAL LASER SCANNING TO EVALUATE THE SPATIAL DISTRIBUTION OF SOIL DISTURBANCE BY SKIDDING OPERATIONS

Abstract: We investigated the disturbance to the surface of a skid trail caused by removing cut timber from inside the forest to the roadside by dragging using terrestrial laser scanning technology. We scanned the study site prior to taking any action, after skidding and after implementing post-harvesting reinstatement to the surface of the skid trail. From the point cloud obtained, we derived an irregular point field. We generated a triangulated irregular network which we then interpolated into a raster digital terrain model with a resolution of 1cm. By comparing the digital terrain models, we analysed the influence of skidding the timber and the influence of post-harvesting reinstatement upon the surface of the skid trail. The surface of the skid trail was most significantly affected in the area where the harvested logs were extracted and stacked for hauling. In the centre section of the trail, where the logs were dragged by a tractor, quite deep tracks were created and the intensity of soil disturbance was comparable to the handling section. The lowest intensity of soil disturbance was found in the area where the skid trail met the roadside. The post-harvesting reinstatement of the working area resulted in levelling the surface of the skid trail and the deepest tracks were filled in. The post-harvesting reinstatement caused a 12% increase of the volume of ruts, a 49% decrease of the volume of mounds of soil and a 6% increase of total soil volume change.

Keywords: Terrestrial Laser Scanning, Skidding Operation, Soil Disturbance, Precision Forestry

iForest 8 (3): 386-393 (2015) - doi: 10.3832/ifor1165-007
https://iforest.sisef.org/contents/?id=ifor1165-007

Research Articles: Spatial heterogeneity of light and tree sapling responses in the understory of disturbed montane forests

Méndez-Dewar G, González-Espinosa M, Equihua M — 2014-10-08

Méndez-Dewar G, González-Espinosa M, Equihua M

SPATIAL HETEROGENEITY OF LIGHT AND TREE SAPLING RESPONSES IN THE UNDERSTORY OF DISTURBED MONTANE FORESTS

Abstract: Attributes and frequency of forest gaps are usually described in reference to a one-dimensional gradient of light, which may relate to their disturbance dynamics. Similarly, species are customarily classified by their light response. We propose that a bi-dimensional light framework facilitates the understanding and comparison of forest systems and the understanding of plant responses to the complex light environment. This light plane is based on two spatially related components: 1) light received directly on a particular point (Focal); and 2) a statistical summary of the immediate environment representing the light conditions surrounding that point (Context). The contrast between these two values is null when Focal = Context and positive when Focal > Context or otherwise negative. Light was assessed using hemispherical photographs using a spatial arrangement of pictures spaced ~3 metres (m) in-between. Eight forest plots were surveyed, each with a central gap of different size. Sapling performance of Alnus acuminata, Cornus excelsa, Liquidambar styraciflua, Persea americana and Quercus laurina was also assessed within these plots. Measurements of stem height, basal diameter, and slenderness allometry were taken over a period of more than two years. We found in the light plane that plots were distributed in a pattern congruent with their estimated degree of disturbance (gap size), which spanned wide areas in the plane. Liquidambar styraciflua. and Quercus laurina were found to be sensitive to Focal light, irrespective of Context light. All species responded to Focal light under negative Contrast. Cornus and Persea grew taller and more slender as Focal light increased, particularly under null contrast. There is evidence suggesting that plant growth is dependent on the contrast measured. Thus, it would be relevant to devise a functional classification of tree species that considers their response to both direct light and luminosity of the immediate environment as measured by a contrast value.

Keywords: Cartesian Plane, Canopy Filter, Light Context, Shade Tolerance, Sunflecks, Light Plane

iForest 8 (4): 448-455 (2015) - doi: 10.3832/ifor1195-007
https://iforest.sisef.org/contents/?id=ifor1195-007

Research Articles: Effects of forest management on bird assemblages in the Bialowieza Forest, Poland

Czeszczewik D, Zub K, Stanski T, Sahel M, Kapusta A, Walankiewicz W — 2014-10-02

Czeszczewik D, Zub K, Stanski T, Sahel M, Kapusta A, Walankiewicz W

EFFECTS OF FOREST MANAGEMENT ON BIRD ASSEMBLAGES IN THE BIALOWIEZA FOREST, POLAND

Abstract: We examined the effects of different intensities of forest management on bird communities in the Bialowieza Forest, eastern Poland. Stands that had been managed for more than 100 years (cutting, planting, removal of dead wood) and stands that were partially protected in nature reserves (sporadic sanitary cutting, removal of dead wood until 2008) were compared with unmanaged stands in the Bialowieza National Park by surveying the bird community during three breeding seasons (2010-2012). Surveys were conducted within three forest habitats: spruce-pine (Pino-Quercetum), lime-hornbeam (Tilio-Carpinetum) and ash-alder (Fraxino-Alnetum). Results showed that habitat structure significantly affected the avian community. The basal area of live trees had a positive effect on abundance of birds, while the density of live trees had negative significant effect on bird abundance and species diversity. We also found significantly lower abundance of insectivorous birds and cavity-nesters in managed compared to unmanaged stands. Birds’ assembly in the spruce-pine and ash-alder stands were most sensitive to management. These results show both that management can be used to sustain bird communities, including species of conservation concern, and that inappropriate management may harm them.

Keywords: Bialowieza Forest, Breeding Bird Communities, Forest Biodiversity, Primeval Stands, Forest Management

iForest 8 (3): 377-385 (2015) - doi: 10.3832/ifor1212-007
https://iforest.sisef.org/contents/?id=ifor1212-007

Research Articles: Assessing the carbon sink of afforestation with the Carbon Budget Model at the country level: an example for Italy

Pilli R, Grassi G, Moris JV, Kurz WA — 2014-10-02

Pilli R, Grassi G, Moris JV, Kurz WA

ASSESSING THE CARBON SINK OF AFFORESTATION WITH THE CARBON BUDGET MODEL AT THE COUNTRY LEVEL: AN EXAMPLE FOR ITALY

Abstract: In the context of the Kyoto Protocol, the mandatory accounting of Afforestation and Reforestation (AR) activities requires estimating the forest carbon (C) stock changes for any direct human-induced expansion of forest since 1990. We used the Carbon Budget Model (CBM) to estimate C stock changes and emissions from fires on AR lands at country level. Italy was chosen because it has one of the highest annual rates of AR in Europe and the same model was recently applied to Italy’s forest management area. We considered the time period 1990-2020 with two case studies reflecting different average annual rates of AR: 78 kha yr-1, based on the 2013 Italian National Inventory Report (NIR, official estimates), and 28 kha yr-1, based on the Italian Land Use Inventory System (IUTI estimates). We compared these two different AR rates with eight regional forest inventories and three independent local studies. The average annual C stock change estimated by CBM, excluding harvest or natural disturbances, was equal to 1738 Gg C yr-1 (official estimates) and 630 Gg C yr-1 (IUTI estimates). Results for the official estimates are consistent with the estimates reported by Italy to the KP for the period 2008-2010; for 2011 our estimates are about 20% higher than the country’s data, probably due to different assumptions on the fire disturbances, the AR rate and the dead wood and litter pools. Furthermore, our analysis suggests that: (i) the impact on the AR sink of different assumptions of species composition is small; (ii) the amount of harvest provided by AR has been negligible for the past (< 3%) and is expected to be small in the near future (up to 8% in 2020); (iii) forest fires up to 2011 had a small impact on the AR sink (on average, < 100 Gg C yr-1). Finally the comparison of the historical AR rates reported by NIR and IUTI with other independent sources gives mixed results: the regional inventories support the AR rates reported by the NIR, while some local studies suggest AR rates somehow intermediate between NIR and IUTI. In conclusion, this study suggests that the CBM can be applied at country level to estimate the C stock changes resulting from AR, including the effect of harvest and fires, though only a comparison with results based on direct field measurements could verify the model’s capability to estimate the real C stock change.

Keywords: Afforestation, Reforestation, Carbon Budget Model, Italy, INFC, IUTI

iForest 8 (4): 410-421 (2015) - doi: 10.3832/ifor1257-007
https://iforest.sisef.org/contents/?id=ifor1257-007

Research Articles: Addressing post-transplant summer water stress in Pinus pinea and Quercus ilex seedlings

Pardos M, Calama R, Mayoral C, Madrigal G, Sánchez-González M — 2014-09-16

Pardos M, Calama R, Mayoral C, Madrigal G, Sánchez-González M

ADDRESSING POST-TRANSPLANT SUMMER WATER STRESS IN PINUS PINEA AND QUERCUS ILEX SEEDLINGS

Abstract: In central Spain, post-transplant water stress produces high seedling mortality after the first summer following outplanting. Our study was designed to determine whether survival and performance of outplanted stone pine (Pinus pinea) and holm oak (Quercus ilex) seedlings in a burned area could be improved by summer irrigation and mulching and to identify whether there is a species-specific adaptive capacity to respond to treatment and environment. Seedlings were outplanted in March 2011 in 200 planting holes in an area of 1.1 ha. Mulch was added in June; irrigation started in July and was repeated every week until mid-September. The severity of the 2011 summer drought constrained growth rates and photosynthetic characteristics, mainly in the non-irrigated seedlings, whose survival at the end of the year after planting was approximately 2.5%. Stone pine and holm oak seedlings responded more to irrigation than to mulching in terms of shoot growth, biomass and survival. Furthermore, stone pine seedlings were found to be more responsive to the partial alleviation of summer drought than holm oak seedlings. Irrigation alone produced similar results to those obtained when both irrigation and mulching were employed. In conclusion, first year summer irrigation should be considered as a planned adaptation measure in the management of outplanted Mediterranean ecosystems, because once a gravimetrically measured soil moisture level as low as 2% is achieved seedling survival and physiological performance can be guaranteed. However, the repercussions for the potential persistence of both species in the area will not only be related to the recurrence and intensity of summer droughts but also to drought duration.

Keywords: Stone Pine, Holm Oak, Irrigation, Drought, Seedling Survival, Physiological Traits

iForest 8 (3): 348-358 (2015) - doi: 10.3832/ifor1256-007
https://iforest.sisef.org/contents/?id=ifor1256-007

Research Articles: Functional turnover from lowland to montane forests: evidence from the Hyrcanian forest in northern Iran

Jafari SM, Zarre S, Alavipanah SK, Ghahremaninejad F — 2014-09-16

Jafari SM, Zarre S, Alavipanah SK, Ghahremaninejad F

FUNCTIONAL TURNOVER FROM LOWLAND TO MONTANE FORESTS: EVIDENCE FROM THE HYRCANIAN FOREST IN NORTHERN IRAN

Abstract: Plant functional traits and functional diversity play key roles in ecosystem functioning. Exploring patterns of functional diversity is of great importance in the management process of forest ecosystems. Altitudinal pattern of plant functional diversity is poorly investigated in Hyrcanian relict forest, N Iran. We explored differences in trait composition between lowland and montane forest types. Altitudinal variation of plant functional traits along 2400 m altitudinal gradient was examined. In order to collect species and vegetation data, 67 vegetation sampling plots were placed along the altitudinal gradient. Eight plant functional traits; related to plant physiognomy, competitive ability and dispersal, were selected for 174 recorded vascular plants and weighted by importance-value of taxa. We used generalized linear model, principal coordinate analysis along with functional diversity metrics to investigate functional changes along the gradient. The importance of different traits such as chamaephyte life form, tiny leaves, dry indehiscent fruits and small seeds increase with altitude. In contrast, other traits including large leaves, taller plants, fleshy fruits, anemophily as well as medium to large seeds decrease with increasing elevation. Functional difference between lowland and montane forest vegetation is strongly supported in our results. Trait associations, different environmental parameters, disturbance type and especially altitude were concluded to be important predictors of functional changes. Vegetation type is a key determinant of functional patterns in temperate forests. We strongly recommend exploring and considering functional diversity in forest management practices.

Keywords: Functional Diversity, Gradient, Hyrcanian Forest, Multivariate Analysis, Vegetation

iForest 8 (3): 359-367 (2015) - doi: 10.3832/ifor1002-008
https://iforest.sisef.org/contents/?id=ifor1002-008

Short Communications: Stomata morphological traits in two different genotypes of Populus nigra L.

Russo G, De Angelis P, Mickle JE, Lumaga Barone MR — 2014-09-16

Russo G, De Angelis P, Mickle JE, Lumaga Barone MR

STOMATA MORPHOLOGICAL TRAITS IN TWO DIFFERENT GENOTYPES OF POPULUS NIGRA L.

Abstract: Populus nigra L. (black poplar) possesses amphistomatic leaves, with large (giant) and normal sized stomata. The role of giant stomata in leaf development, and the consequences on stomatal density in adult leaves remains elusive. This paper describes the characteristics of ordinary and giant stomata in leaves of two black poplar genotypes (58-861 with large leaves from northern Italy, and Poli with small leaves from southern Italy). Stomatal traits in both genotypes were studied using light microscopy on mature leaf adaxial and abaxial epidermal impressions. Moreover, scanning electron microscopy was applied to study giant and normal stomata in early, young, and mature leaves. Leaf abaxial surfaces in the two genotypes revealed variable sizes and patterns of stomata related to differences in intrinsic water use efficiency (Wi). These observations provided evidence of different stomatal types in mature black poplar leaves, and new information regarding the presence and potential role of giant stomata in black poplar leaves.

Keywords: Giant Stomata, Poplar Clones, Genotypes, Populus, SEM

iForest 8 (4): 547-551 (2015) - doi: 10.3832/ifor1104-007
https://iforest.sisef.org/contents/?id=ifor1104-007

Research Articles: Visible and near infrared spectroscopy for predicting texture in forest soil: an application in southern Italy

Conforti M, Froio R, Matteucci G, Buttafuoco G — 2014-09-09

Conforti M, Froio R, Matteucci G, Buttafuoco G

VISIBLE AND NEAR INFRARED SPECTROSCOPY FOR PREDICTING TEXTURE IN FOREST SOIL: AN APPLICATION IN SOUTHERN ITALY

Abstract: Texture is a primary variable affecting the total amount of carbon stock in the soil. The standard methods for determining soil texture, however, are still conducted manually and are largely time-consuming. Reflectance spectroscopy in the visible, near infrared (Vis-NIR, 350-2500 nm) spectral region could be an alternative to standard laboratory methods. The aim of this paper was to develop calibration models based on laboratory Vis-NIR spectroscopy and PLSR analysis to estimate the texture (sand: 2-0.05 mm; silt: 0.05-0.002 mm; clay: <0.002 mm) in a forest area of southern Italy. An additional objective was to produce continuous maps of sand, silt and clay through a geostatistical approach. Soil samples were collected at 235 locations in the study area, and then dried, sieved at 2 mm and analyzed in laboratory for soil texture and Vis-NIR spectroscopic measurements. Spectra showed that soil samples could be spectrally separable on the basis of classes of texture. To establish the relationships between spectral reflectance and soil texture (sand, silt and clay) partial least squared regression (PLSR) analysis was applied to 175 soil samples, while the remaining 60 samples were used to validate the models. The optimum number of factors to be retained in the calibration models was determined by leave-one-out cross-validation. Results of cross validation of calibration models indicated that the models fitted quite well and the values of R2 ranged between a minimum value of 0.74% for silt and a maximum value of 0.84 for sand content. Results for validation were satisfactory for sand content (R2=0.81) and clay content (R2=0.80) and less satisfactory for silt content (R2=0.70). Geostatistics coupled with Vis-NIR reflectance spectroscopy allowed us to produce continuous maps of sand, silt and clay, which are of critical importance for understanding and managing forest soils.

Keywords: Forest Soils, Soil Texture, Vis-NIR Spectroscopy, Geostatistics, Southern Italy

iForest 8 (3): 339-347 (2015) - doi: 10.3832/ifor1221-007
https://iforest.sisef.org/contents/?id=ifor1221-007

Research Articles: Effects of planting density on the distribution of biomass in a douglas-fir plantation in southern Italy

Marziliano PA, Coletta V, Menguzzato G, Nicolaci A, Pellicone G, Veltri A — 2014-09-09

Marziliano PA, Coletta V, Menguzzato G, Nicolaci A, Pellicone G, Veltri A

EFFECTS OF PLANTING DENSITY ON THE DISTRIBUTION OF BIOMASS IN A DOUGLAS-FIR PLANTATION IN SOUTHERN ITALY

Abstract: The effects of initial planting densities on the distribution of above-ground biomass of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) were investigated in a plantation in southern Italy. Allometric equations designed for the plantation under study were used to estimate above-ground biomass and in particular partitioning to stem and crown compartments. A comparison between biomass estimated with allometric equations and biomass estimated with a constant biomass expansion factor (BEF) from the Italian National Forest Inventory (INFC 2005) was carried out. Moreover, a BEF calculated as the ratio of total above-ground or compartment biomass to stem volume was used to define the sensitivity of BEF to age and to tree density. Variation of above-ground standing biomass estimated with allometric equations was evaluated according to 6 differing planting densities (833, 1000, 1250, 1667, 2000 and 2500 trees per hectare). In the first 20 years after planting higher biomass stock was detected in high density plots, but after the age of 32 years differences between plots disappeared. When the plantation was 40 years old, a higher amount of total biomass was observed in plots of 2000 trees per hectare (about 405 Mg ha-1), a lower amount in plots of 2500 trees per hectare (about 381 Mg ha-1). The Douglas-fir plantation has a total above-ground carbon stock of 197 Mg C ha-1 at the age of 40 and a mean annual CO2 sequestration of 18 Mg ha-1 y-1. Constant BEF from INFC underestimated biomass on average by 11% for ages 15 and 25 and overestimated biomass on average by 16% for older ages. BEFs expressed as a ratio of biomass to stem volume significantly depended upon age and planting density, with decreasing trends for total, stem and crown compartments. Our results indicated that total above-ground biomass production is not influenced by different tree density if considered over a long period. If cutting cycles are short, planting density on average of 2000 trees per hectare may ensure high biomass production rates; if cutting cycles are longer, 1000-1200 trees per hectare could also be a valid choice.

Keywords: Allometric Equations, Biomass, Biomass Expansion Factor, Carbon, Douglas-fir, Planting Density, Spacing Trial

iForest 8 (3): 368-376 (2015) - doi: 10.3832/ifor1078-007
https://iforest.sisef.org/contents/?id=ifor1078-007

Research Articles: Fine-scale spatial genetic structure in a multi-oak-species (Quercus spp.) forest

Curtu AL, Craciunesc I, Enescu CM, Vidalis A, Sofletea N — 2014-09-05

Curtu AL, Craciunesc I, Enescu CM, Vidalis A, Sofletea N

FINE-SCALE SPATIAL GENETIC STRUCTURE IN A MULTI-OAK-SPECIES (QUERCUS SPP.) FOREST

Abstract: Patterns of fine-scale spatial distribution of multilocus genotypes can provide valuable insights into the biology of forest tree species. Here we tested for the existence of spatial genetic structure (SGS) in a four-oak-species forest with contrasting species abundances and hybridization rates. A total of 483 adult trees were mapped over 8.6 ha and genotyped using 10 highly polymorphic genomic regions. A weak but significant SGS was observed in each of the four oak species, with Quercus frainetto, the species with the lowest density in the sampling plot, exhibiting the strongest SGS. The values of the Sp statistic were 0.0033, 0.0035, 0.0042, and 0.0098 for Q. petraea, Q. robur, Q. pubescens, and Q. frainetto, respectively. The spatial correlogram of the total population was significantly different when hybrids were removed from the analysis, which suggests that hybridization influenced the SGS. Interspecific SGSs were significantly correlated with the rates of hybridization. Implications of the obtained results for the conservation and management of forest genetic resources are discussed.

Keywords: Spatial Genetic Structure, Quercus, Oak Species, Population Density, Hybridization

iForest 8 (3): 324-332 (2015) - doi: 10.3832/ifor1150-007
https://iforest.sisef.org/contents/?id=ifor1150-007

Research Articles: Modeling stand mortality using Poisson mixture models with mixed-effects

Zhang X-Q, Lei Y-C, Liu X-Z — 2014-09-05

Zhang X-Q, Lei Y-C, Liu X-Z

MODELING STAND MORTALITY USING POISSON MIXTURE MODELS WITH MIXED-EFFECTS

Abstract: Stand mortality models play an important role in simulating stand dynamic processes. Periodic stand mortality data from permanent plots tend to be dispersed, and frequently contain an excess of zero counts. Such data have commonly been analyzed using the Poisson distribution and Poisson mixture models, such as the zero-inflated Poisson model (ZIP), and the Hurdle Poisson model (HP). Based on mortality data obtained from sixty Chinese pine (Pinus tabulaeformis) permanent plots near Beijing, we added the random-effects to the Poisson mixture models. Results showed that the random-effects in the ZIP model was not convergent, and HP mixed-effects model performed better in modeling stand mortality than the Poisson fixed-effects model, the Poisson mixed-effects model, the ZIP fixed-effects model and the HP fixed-effects model. Moreover, the HP model accounts for two sources of dispersion, the first accounting for extra zeros and the second accounting to some extent for the dispersion due by individual heterogeneity in the positive set. We also found that stand mortality was negatively related to stand arithmetic mean diameter and positively related to dominant height.

Keywords: Hurdle Model, Mixed Model, Poisson Model, Stand Mortality, Zero Inflated Model

iForest 8 (3): 333-338 (2015) - doi: 10.3832/ifor1022-008
https://iforest.sisef.org/contents/?id=ifor1022-008

Review Papers: Open field-applicable instrumental methods for structural and functional assessment of whole trees and stands

Cermák J, Nadezhdina N, Trcala M, Simon J — 2014-09-03

Cermák J, Nadezhdina N, Trcala M, Simon J

OPEN FIELD-APPLICABLE INSTRUMENTAL METHODS FOR STRUCTURAL AND FUNCTIONAL ASSESSMENT OF WHOLE TREES AND STANDS

Abstract: This illustrated review is aimed to provide succinct account of different methods applicable for obtaining objective information about the functional ecology of forest sites and stands (and also, e.g., orchards, watersheds, parks or alleys) for the purposes of phytotechnology or precise forestry. Management strategies must consider preservation of many important functions of forests in the landscape. Management methodologies include classical forestry approaches based on classification of the natural environment according to climatic zones, soil characteristics and composition of herbaceous as well as woody vegetation. One possibility for obtaining objective information came with the development of ecologically applicable instrumentation, allowing studies on the whole tree and stand levels to be undertaken anywhere in the field. Information may be derived at sites that are not permanently observed and are not equipped with additional constructions, such as towers, masts, or greenhouses. These field applicable methods are focused especially on tree and stand macrostructure, water relations and functional parameters of trees. In addition, problems associated with interactions between trees and different organisms are also discussed. A series of methods based on different principles is useful to measure mostly quantitative, operative or effective tree parameters as tree crowns and leaf distribution, stems (or large tree trunks) and root systems including skeleton and absorptive fine roots. This is sometimes possible to do with rather simple methods, but instrumental methods prevail especially for root studies. In addition to several classical measurement principles including anatomical or mechanical sensing, the methods work with sound speed (acoustic tomography) using electromagnetic rays of different wavelength (from radar to optical), electric conductivity or impedance, supersonic air stream and thermodynamics for example. Methods for data evaluation and examples of application are also included. The whole complex system approach should serve for different scientific fields (including hydrology, landscape care, horticulture, forensic engineering, etc.) and especially to support precise forestry.

Keywords: Instrumental and Simple Methods, Geometrical and Effective Parameters, Tree Crown, Stem (trunk) and Root System, Complex Studies, Water and Energy

iForest 8 (3): 226-278 (2015) - doi: 10.3832/ifor1116-008
https://iforest.sisef.org/contents/?id=ifor1116-008

Technical Reports: Effects of wildfires on peak discharges in watersheds

Leopardi M, Scorzini AR — 2014-09-03

Leopardi M, Scorzini AR

EFFECTS OF WILDFIRES ON PEAK DISCHARGES IN WATERSHEDS

Abstract: Wildfires can alter the hydrological processes in watersheds resulting in increases in peak discharge - one of the most important hydrological variables used in water resources applications. It thus follows that the standard methods used to calculate rainfall runoff should be modified in order to model the potential changes in watershed response under post-fire conditions. However, no reliable methodology for quantitatively assessing the effects of wildfires on hydrological parameters, such as curve numbers or runoff coefficients, has been identified to date. The approaches currently used are usually site-specific, mainly based on personal experience or very simple empirical strategies and then affected by a degree of uncertainty. This paper addresses issues regarding the estimation of the Soil Conservation Service Curve Number (SCS-CN or CN) and considers the case study of San Giuliano, L’Aquila (Italy), a small urban basin recently affected by a wildfire that resulted in a significant reduction in forest cover. The effects of the fire on runoff are modelled by adjusting CNs according to existing approaches from the literature in order to perform a sensitivity analysis for post-fire conditions; this allows us to examine the effects of the variability in model input parameters (estimates of post-fire CNs) upon expected peak discharges related to different return period storms. The fire effect ratio, which can be seen as a global parameter for describing alterations in the watershed response due to fire, is calculated by dividing post-fire peak discharge by pre-fire peak discharge. For the present case study, this ratio ranged between 1.1 and 2.3, indicating the urgent need for quantitative research on the effects of wildfires on the hydrological variables affecting runoff calculations.

Keywords: Wildfire, Curve Number, Peak Discharge, Runoff, GIS

iForest 8 (3): 302-307 (2015) - doi: 10.3832/ifor1120-007
https://iforest.sisef.org/contents/?id=ifor1120-007

Research Articles: Arbuscular mycorrhizal fungal symbiosis with Sorbus torminalis does not vary with soil nutrients and enzyme activities across different sites

Moradi M, Shirvany A, Matinizadeh M, Etemad V, Naji HR, Abdul-Hamid H, Sayah S — 2014-09-03

Moradi M, Shirvany A, Matinizadeh M, Etemad V, Naji HR, Abdul-Hamid H, Sayah S

ARBUSCULAR MYCORRHIZAL FUNGAL SYMBIOSIS WITH SORBUS TORMINALIS DOES NOT VARY WITH SOIL NUTRIENTS AND ENZYME ACTIVITIES ACROSS DIFFERENT SITES

Abstract: Effects of soil chemical properties on arbuscular mycorrhizal fungal (AMF) symbiosis with wild service tree (Sorbus torminalis L. Crantz) were examined for study the rates of root colonization at three forest sites: Kheiroud, Lalis, and Takrin in northern Iran. Soil characteristics including pH, available phosphorus (P), potassium (K), organic matter, total nitrogen, acid and alkaline phosphatase activities, CaCO3, spore density (SD) and AMF colonization of soil and root samples were analyzed. The study sites were investigated in spring and autumn to highlight the effects of soil chemical properties on AMF statues for better nurseries and reforestation management of this rare tree species in forests. Changes in soil pH, P, K, organic matter, total nitrogen, acid and alkaline phosphatase, CaCO3, SD, and AMF colonization of soil and root samples were analyzed at the study sites. K, pH, root colonization, SD and acid phosphatase activity showed no significant differences among sites in spring and autumn, while total nitrogen, P, organic matter and alkaline phosphatase activities showed significant differences among sites and seasons. AMF colonization rates were more than 51% and 32% of roots in spring and autumn, respectively. No correlation between root colonization and soil chemical parameters in spring and autumn were detected. There was no correlation between percentage of AM root colonization and SD nor other soil parameters in spring and autumn. SD and CaCO3 were significantly negatively correlated in spring and autumn. Despite differences in soil characteristics, the results showed that SD and root colonization were not significantly different among the sites. They also showed that wild service trees had strong symbiosis with AMF, while soil properties might not have a significant effect on this symbiosis. Therefore, colonized seedlings can be considered as an appropriated method for reforestation and conservation of this rare tree species.

Keywords: Arbuscular Mycorrhizae, Soil Nutrients, Colonization, Soil Enzyme, Sorbus torminalis

iForest 8 (3): 308-313 (2015) - doi: 10.3832/ifor1236-008
https://iforest.sisef.org/contents/?id=ifor1236-008

Research Articles: An index of structural complexity for Apennine beech forests

Sabatini FM, Burrascano S, Lombardi F, Chirici G, Blasi C — 2014-09-03

Sabatini FM, Burrascano S, Lombardi F, Chirici G, Blasi C

AN INDEX OF STRUCTURAL COMPLEXITY FOR APENNINE BEECH FORESTS

Abstract: A broad interest exists in developing structure-based indicators to use as proxies for other attributes that are difficult to assess, such as biological diversity. Summary variables that account for stand-scale forest structural complexity could facilitate the comparison among stands and provide a means of ranking stands in terms of their potential contribution to biodiversity. We developed an index of structural heterogeneity (SHI) for beech forests in southern Italy: (i) we established a preliminary list of 23 structural variables obtained from data routinely collected in forest inventories; (ii) we quantified these variables in a set of 64 beech-dominated stands encompassing a wide range of variability in the Cilento, Vallo di Diano and Alburni National Park; (iii) we identified a core set of attributes that take into account the main sources of structural heterogeneity identified in reference old-growth forests; and (iv) we combined these core attributes into a simple additive index (SHI). We identified eight core attributes that were rescaled to the range 0 to 10 using regression equations based on raw attribute data. The SHI was calculated as the sum of these attribute scores and then expressed as a percentage. The index performance was evaluated against ten reference old-growth beech stands in the Apennines. The index ranged between 38 and 79.1 (median=59.4) and was distributed normally for the calibration dataset. The SHI successfully discriminated between old-growth (range=71.9-99.9, median=85.1) and early-mature to mature forests. Furthermore, the SHI linearly increased with stand age and was higher in multi-layer high forests than in single- and double-layer forests. However, a large variation was detected within both management types and age classes. SHI could be helpful for foresters as a tool for quantifying and comparing structural heterogeneity before and after a silvicultural intervention aimed at restoring the structural complexity in second-growth stands.

Keywords: “Cilento - Vallo di Diano and Alburni” National Park, Fagus sylvatica, National Forest Inventories, Old-growth Forests, Structural Heterogeneity Index

iForest 8 (3): 314-323 (2015) - doi: 10.3832/ifor1160-008
https://iforest.sisef.org/contents/?id=ifor1160-008

Technical Reports: Categorization of field trials with GM plants in the Netherlands: applicable to field trials with GM forest trees?

Glandorf DC — 2014-08-31

Glandorf DC

CATEGORIZATION OF FIELD TRIALS WITH GM PLANTS IN THE NETHERLANDS: APPLICABLE TO FIELD TRIALS WITH GM FOREST TREES?

Abstract: In the Netherlands, criteria have been set for field trials with genetically modified (GM) plants. These criteria are based on the step-by-step principle as described in European Directive 2001/18/EC. Three categories of field trials are defined. The first category concerns small-scale field trials with GM plants that are not well characterised on the molecular and phenotypic level. Confinement measures are applied in order to limit potential adverse effects to the field location. The second category consists of small-scale field experiments with GM plants that are better characterized. Confinement measures are no longer necessary since sufficient information is available to assess potential adverse effects on human health and the environment for these trials. The third category consists of large-scale field trials with fully characterised GM plants and without the need of confinement measures. For each category, a new permit is required. This system has been used for several crops, including apple and poplar trees and may also be applicable for trials with GM forest trees.

Keywords: Field Trials, Genetically Modified, GM Crops, GM Trees, Environmental Risk Assessment

iForest 8 (2): 222-225 (2015) - doi: 10.3832/ifor1311-008
https://iforest.sisef.org/contents/?id=ifor1311-008

Research Articles: Seed trait and rodent species determine seed dispersal and predation: evidences from semi-natural enclosures

Yi X, Wang Z, Liu C, Liu G — 2014-08-28

Yi X, Wang Z, Liu C, Liu G

SEED TRAIT AND RODENT SPECIES DETERMINE SEED DISPERSAL AND PREDATION: EVIDENCES FROM SEMI-NATURAL ENCLOSURES

Abstract: Seed traits affect seed dispersal by animals. However, the combined role of seeds and dispersers in determining seed dispersal is not well explored. We attempted to test how seed traits and predators determine seed dispersal and predation interaction in a rodent-mediated seed dispersal system. Semi-natural enclosure experiments were conducted to investigate seed dispersal and predation of five sympatric tree species with different seed traits, Juglans mandshurica, Quercus mongolica, Pinus koraiensis, Corylus mandshurica and C. heterophylla by three rodent species, Apodemus peninsulae, Tamias sibiricus and Clethrionomys rufocanus showing different body sizes, hoarding behaviors and activity rhythms. Our results demonstrated that seed species with thick coat were removed more slowly than thin-coated seeds in regardless of rodent species, reflecting a consistent negative effect of seed coat on seed dispersal. Seeds with thick coat were less likely to be eaten both in situ and after removal by small rodents. Seeds with high caloric value were more likely to be larder-hoarded, whereas seed traits showed no influence on scatter-hoarding. Rodent species with large body size tended to eat more seeds in situ, while small-sized rodents preferred to eat seeds after removal. Large-sized rodent species scatter-hoarded more seeds, however, small-sized rodents larder-hoarded more seeds. Seeds with thick coat showed high mutualism but low predation with rodents, while rodents with large size showed low mutualism but high predation with seeds. Our results indicate that both seeds and predators play important roles in determining seed dispersal and predation in the seed-rodent dispersal system.

Keywords: Body Size, Caloric Value, Seed Coat, Seed Dispersal

iForest 8 (2): 207-213 (2015) - doi: 10.3832/ifor1185-008
https://iforest.sisef.org/contents/?id=ifor1185-008

Research Articles: Environmental niche and distribution of six deciduous tree species in the Spanish Atlantic region

Roces-Díaz JV, Jiménez-Alfaro B, Álvarez-Álvarez P, Álvarez-García MA — 2014-08-28

Roces-Díaz JV, Jiménez-Alfaro B, Álvarez-Álvarez P, Álvarez-García MA

ENVIRONMENTAL NICHE AND DISTRIBUTION OF SIX DECIDUOUS TREE SPECIES IN THE SPANISH ATLANTIC REGION

Abstract: Understanding the influence of environmental factors on the distribution of tree species is essential for developing management actions at regional level. We computed species distribution models for six European tree species to determine their potential niche in the Spanish Atlantic region, where deciduous forests are relatively well preserved. We used data from the national Forest Inventory and topo-climatic and soil variables to construct distribution models by the Generalized Linear Model procedure. The main factors found to determine the presence of the selected species were minimum winter temperature and mineral fertility of soils. Suitable habitats for Quercus petraea and F. sylvatica were mainly high-altitude areas with low minimum temperatures. In contrast, Q. robur and C. sativa were restricted to low altitudes and warmer conditions. Betula pubescens was not influenced by the elevation, probably because it is adapted to Atlantic conditions, and distribution of this species was associated with low fertility soils. Although the submediterranean Q. pyrenaica was positively influenced by the slope, model performance was poor for this species, possibly because of the truncated environmental range of the species in the study area. The findings suggest that temperature rather than moisture is shaping the distribution of deciduous trees at the southern limit of the Atlantic biogeographic region. We also note that the strong elevational difference between the warm coast and the cold mountains may determine the geographical disjunction between Q. robur and Q. petraea in southern Europe.

Keywords: Species Distribution Models, Topo-climatic Variables, Quercus species, Fagus sylvatica, Castanea sativa, Betula pubescens, Iberian Peninsula, Deciduous Forests

iForest 8 (2): 214-221 (2015) - doi: 10.3832/ifor1183-008
https://iforest.sisef.org/contents/?id=ifor1183-008

Research Articles: Soil C:N stoichiometry controls carbon sink partitioning between above-ground tree biomass and soil organic matter in high fertility forests

2014-08-26

Alberti G, Vicca S, Inglima I, Belelli-Marchesini L, Genesio L, Miglietta F, Marjanovic H, Martinez C, Matteucci G, D’Andrea E, Peressotti A, Petrella F, Rodeghiero M, Cotrufo MF

SOIL C:N STOICHIOMETRY CONTROLS CARBON SINK PARTITIONING BETWEEN ABOVE-GROUND TREE BIOMASS AND SOIL ORGANIC MATTER IN HIGH FERTILITY FORESTS

Abstract: The release of organic compounds from roots is a key process influencing soil carbon (C) dynamics and nutrient availability in terrestrial ecosystems. Through this process, plants stimulate microbial activity and soil organic matter (SOM) mineralization thus releasing nitrogen (N) that sustains gross and net primary production (GPP and NPP, respectively). Root inputs also contribute to SOM formation. In this study, we quantified the annual net root-derived C input to soil (Net-Croot) across six high fertility forests using an in-growth core isotope technique. On the basis of Net-Croot, wood and coarse root biomass changes, and eddy covariance data, we quantified net belowground C sequestration. Belowground C accumulation and GPP were inversely related to soil C:N, but not to climate or stand age. Soil C content and C:N were also related to soil texture. At these high fertility sites, biomass growth did not change with soil C:N; however, biomass growth-to-GPP ratio significantly increased with increasing soil C:N. This was true for both our six forest sites and for another 23 high fertility sites selected at a global scale. We suggest that, at high fertility sites, plant N demand interacts with soil C:N stoichiometry and microbial activity, resulting in higher allocation of C to above ground tree biomass with increasing soil C:N ratio. When C:N is high, microbes have a low C use efficiency, respire more of the fresh C inputs by roots and prime SOM decomposition, thereby increasing N availability for tree uptake. Soil C sequestration would therefore decrease, whereas the extra N released during SOM decomposition can promote tree growth and ecosystem C sink allocation in aboveground biomass. Conversely, C is sequestered in soil when low soil C:N promotes microbial C use efficiency and new SOM formation and stabilization on clay particles.

Keywords: Net Root-derived Carbon, Ingrowth Cores, Soil C:N, Carbon Sequestration, Carbon Partitioning, Isotopes

iForest 8 (2): 195-206 (2015) - doi: 10.3832/ifor1196-008
https://iforest.sisef.org/contents/?id=ifor1196-008

Research Articles: Estimating the sensitivity to desertification of Italian forests

Salvati R, Salvati L, Corona P, Barbati A, Ferrara A — 2014-08-26

Salvati R, Salvati L, Corona P, Barbati A, Ferrara A

ESTIMATING THE SENSITIVITY TO DESERTIFICATION OF ITALIAN FORESTS

Abstract: The present study assesses the level of sensitivity to desertification of forest types in Italy between 2000 and 2010 on a fine resolution scale using the Environmental Sensitive Area (ESA) scheme. The proposed methodology identifies and ranks the level of sensitivity of fourteen forest types and quantifies the changes in their level of sensitivity over time as a contribution to understanding of complex landscape-forest interactions in Mediterranean ecosystems. Only few forest types showed a relatively high sensitivity level, suggesting that forests may positively contribute to the mitigation of land degradation processes in the Mediterranean region. Forest types showing the highest sensitivity are native types mostly adapted to dry Mediterranean landscapes, introduced vegetation types and highly-fragmented and heterogeneous forest types. Results suggest that: (i) high-quality and biodiversity-rich forest types (e.g., beech, mountain pine forests) may act as vegetation buffer mitigating the increase of land sensitivity to desertification at the landscape scale; and (ii) the remaining forest types (especially highly fragmented, low-quality or low-biodiversity classes in areas with severe soil and climate conditions) may undergo increases in land sensitivity to desertification and should be protected through specific management measures as also implemented in the framework of the National Action Plans to Combat Desertification.

Keywords: Environmental Indicators, ESAI, Desertification, Forests, Mediterranean Basin, Climate, Soil

iForest 8 (3): 287-294 (2015) - doi: 10.3832/ifor1111-008
https://iforest.sisef.org/contents/?id=ifor1111-008

Research Articles: Potential spread of forest soil-borne fungi through earthworm consumption and casting

Montecchio L, Scattolin L, Squartini A, Butt KR — 2014-08-26

Montecchio L, Scattolin L, Squartini A, Butt KR

POTENTIAL SPREAD OF FOREST SOIL-BORNE FUNGI THROUGH EARTHWORM CONSUMPTION AND CASTING

Abstract: To test if forest soil-borne fungi concerned with plant health can be selectively dispersed by earthworms, 10 fungal species isolated from 5 forests were presented, at 2 concentrations, to 3 ecologically distinct earthworm species in laboratory trials. Between 5 and 13 days after introduction, casts were collected, where possible, from each earthworm species fed with a different fungus. These casts were analysed, using molecular methods, for the presence of the given fungus and its vitality verified through traditional plating techniques. The research confirmed that earthworms have an important role in dispersal of soil fungi in forests, and that such activity can depend on the taxonomical position of the fungus, ecological category of the earthworm species involved and the fungal concentration. In certain instances there is a suggestion that some fungi may be toxic to some earthworms at the given concentrations, which equated to those within and outside of the rhizosphere.

Keywords: Earthworms, Soil-borne Fungi, Fungal Inoculum, Ecology, Dispersal

iForest 8 (3): 295-301 (2015) - doi: 10.3832/ifor1217-008
https://iforest.sisef.org/contents/?id=ifor1217-008

Research Articles: Concordance between vascular plant and macrofungal community composition in broadleaf deciduous forests in central Italy

2014-08-22

Landi M, Salerni E, Ambrosio E, D’Aguanno M, Nucci A, Saveri C, Perini C, Angiolini C

CONCORDANCE BETWEEN VASCULAR PLANT AND MACROFUNGAL COMMUNITY COMPOSITION IN BROADLEAF DECIDUOUS FORESTS IN CENTRAL ITALY

Abstract: We examined the concordance between vascular plants and macrofungi (grouped into trophic groups) in Mediterranean forest habitats (central Italy). Our goal was to test how consistently plant and fungi groups classify plots in a broadleaf deciduous forest dominated by Quercus cerris. Our hypothesis was that groups of plants can be used as surrogates for the classification of macrofungal communities. The test of concordance comprised two steps: 1) the plant species data sets were subjected to cluster analysis, to obtain three classifications based on presence of all plants, presence and frequency of only woody species; 2) Multiple Response Permutation Procedures (MRPP) was used to test the performance of each plant classification applied to the fungi data sets. The sample scores along the first PCA axis was used to investigate the relationships between compositional patterns. In the concordance analysis, the classification of only woody plants provided better results than the classification obtained with herbaceous and woody plants together. Cross-tests gave the best results when the “woody plants” classification was applied to ectomycorrhizal fungi (EMF) and, to a certain extent, to humicolous saprotrophs (Sh). The ordination analysis indicated that the frequency of woody plants follows a similar spatial distribution to EMF and Sh fungal groups and is therefore expected to discriminate the same environmental gradients. Many EMF exhibit preferences for few (one or two) hosts. Significant associations were found among a greater number of EMF and woody plant species. Woody plants such as Sorbus domestica and Prunus spinosa appear to be associated with many EMF. The combination of a high frequency of Fraxinus oxycarpa and Quercus petraea seems to promote distinct assemblages of EMF and Sh fungi. Then, characteristic assemblages of fungi were found in association with certain tree and shrub combinations.

Keywords: Deciduous Oaks, Ectomycorrhizal Fungi, Host Specificity, Saprotrophic Fungi, Surrogates, Trophic Groups

iForest 8 (3): 279-286 (2015) - doi: 10.3832/ifor1199-008
https://iforest.sisef.org/contents/?id=ifor1199-008

Research Articles: Individual-based approach as a useful tool to disentangle the relative importance of tree age, size and inter-tree competition in dendroclimatic studies

Rozas V — 2014-08-21

Rozas V

INDIVIDUAL-BASED APPROACH AS A USEFUL TOOL TO DISENTANGLE THE RELATIVE IMPORTANCE OF TREE AGE, SIZE AND INTER-TREE COMPETITION IN DENDROCLIMATIC STUDIES

Abstract: In this work, an individual-based approach was used to assess the relative importance of tree age, size, and competition in modulating the individual dendroclimatic response of Quercus robur L. This was performed in a multi-aged forest in northwestern Spain under a wet Atlantic climate. All trees in five replicated forest stands with homogeneous soil conditions were mapped and inter-tree competition was quantified with a distance-dependent competition index. Tree rings of cored trees were crossdated and total age was estimated on individuals where the pith was missed. The climatic response was evaluated by bootstrapped correlations of individual tree-ring chronologies with climatic records. Inter-annual growth variation, i.e., mean sensitivity, was independent of tree age and bole diameter, but modulated by competition. Water excess in previous summer-autumn and spring negatively affected growth, while warmer September conditions favored growth. Individual response to climate was independent of tree age, but related to the joint effect of tree bole diameter and competition. Larger oaks in less competitive environments responded more plastically to climatic stress, while smaller trees under high competition levels were less responsive to climate. Strong inter-tree competition reduced growth plasticity but amplified the vulnerability of smaller oaks to the particularly rainy conditions of the study area. These findings suggest that inter-tree competition is a relevant size-mediated extrinsic factor that can potentially modulate individual radial growth variation and its response to limiting climatic conditions in temperate deciduous forests. This study highlights the value of individual-based approach as a useful tool that informs about the relative contribution of factors modulating the climatic response of tree-ring growth.

Keywords: Climate-Growth Response, Competitive Effect, Dendroecology, Individual Variation, Quercus robur, Size Effect, Tree Age

iForest 8 (2): 187-194 (2015) - doi: 10.3832/ifor1249-007
https://iforest.sisef.org/contents/?id=ifor1249-007

Research Articles: Forest litter as the mulch improving growth and ectomycorrhizal diversity of bare-root Scots pine (Pinus sylvestris) seedlings

Aučina A, Rudawska M, Leski T, Skridaila A, Pašakinskiene I, Riepšas E — 2014-08-20

Aučina A, Rudawska M, Leski T, Skridaila A, Pašakinskiene I, Riepšas E

FOREST LITTER AS THE MULCH IMPROVING GROWTH AND ECTOMYCORRHIZAL DIVERSITY OF BARE-ROOT SCOTS PINE (PINUS SYLVESTRIS) SEEDLINGS

Abstract: In this paper, we report the influence of pine, oak and spruce forest litter on the growth and ectomycorrhizal (ECM) formation of Scots pine seedlings after the first growing season in a bare-root forest nursery. The mixture of collected forest litters and humus were used to obtain a 20-cm mulching layer on the prepared seedbeds. The concentrations of all nutrients and the C/N ratio of growth media were significantly higher in forest litter treatments than in negative control represented by mineral soil without litter. Addition of each forest litter type significantly enhanced pine seedling height and root-collar diameter compared to negative control. A significant positive influence on dry mass of stem, needles, roots and total dry mass of the seedling has been found only for pine litter. Based on molecular identification, seven ECM fungal taxa (Wilcoxina mikolae, Suillus luteus, Cenococcum geophilum, Meliniomyces bicolor, Laccaria laccata, unidentified Atheliaceae, unidentified Ascomycetes) were distinguished in the observed mycorrhizal communities. Each forest litter type significantly increased the total number of mycorrhizal tips and ECM fungal diversity compared to the control soil. However, results showed a lack of significant differences in species composition and relative abundance of ECM fungi between different litter types. Such result suggests that forest litter has not been a key source of inoculum for tested fungal species, as root systems of all pine seedlings from different litter types were dominated by a few nursery- adapted ECM fungi, probably originating from natural air-borne inoculum. Our data rather indicate that forest litter considerably improves environmental conditions for development of ECM fungi previously present in the nursery soil. Therefore, any of the forest litter types used in our studies may be able to promote planting stock quality on a small scale in the nursery phase.

Keywords: Pinus sylvestris, Seedlings, Forest Nursery, Ectomycorrhiza

iForest 8 (4): 394-400 (2015) - doi: 10.3832/ifor1083-008
https://iforest.sisef.org/contents/?id=ifor1083-008

Research Articles: Application of fungicides and urea for control of ash dieback

Hauptman T, Celar FA, de Groot M, Jurc D — 2014-08-13

Hauptman T, Celar FA, de Groot M, Jurc D

APPLICATION OF FUNGICIDES AND UREA FOR CONTROL OF ASH DIEBACK

Abstract: Ash dieback is caused by a highly pathogenic fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea). Possibilities for disease control are limited, and treatment of fallen leaf debris to prevent sporulation of the pathogen is one of the possible options to control the disease. In some cases chemical treatments could be used, but data on effective chemical agents for control of the ash dieback are lacking. The purpose of this study was to examine the effect of different chemical fungicides and urea on the pathogen. Out of eight tested fungicides, mycelial growth in Petri plates as well as development of H. pseudoalbidus apothecia on ash leaf petioles were most efficiently inhibited by carbendazim. Urea also proved to be effective in prevention of apothecial formation. In addition to inhibition of the pathogen, urea accelerates the degradation of treated leaf debris. Therefore, the use of urea for treatment of infected ash leaf debris could be more effective than the use of fungicides and also more environmentally acceptable.

Keywords: Hymenoscyphus pseudoalbidus, Chemical Control, Mycelial Growth, Leaf Petioles, Apothecia Formation

iForest 8 (2): 165-171 (2015) - doi: 10.3832/ifor1272-008
https://iforest.sisef.org/contents/?id=ifor1272-008

Research Articles: Seven Ulmus minor clones tolerant to Ophiostoma novo-ulmi registered as forest reproductive material in Spain

2014-08-13

Martín JA, Solla A, Venturas M, Collada C, Domínguez J, Miranda E, Fuentes P, Burón M, Iglesias S, Gil L

SEVEN ULMUS MINOR CLONES TOLERANT TO OPHIOSTOMA NOVO-ULMI REGISTERED AS FOREST REPRODUCTIVE MATERIAL IN SPAIN

Abstract: The Spanish elm programme began in 1986 in response to the devastating impact of Dutch elm disease on natural elm stands and urban trees. Its main objectives were to conserve remaining genetic resources and select and breed tolerant native elm genotypes. After 27 years of work conducting susceptibility trials on thousands of elm genotypes, the first seven tolerant Ulmus minor trees are now being registered by the Spanish Environmental Administration. This paper presents the results of the susceptibility tests on these clones and their distinctive genetic, morphological and phenological features. In all susceptibility trials the commercial “Sapporo Autumn Gold” clone, which is highly tolerant to O. novo-ulmi, was used as a control. The registered clones were named “Ademuz”, “Dehesa de la Villa”, “Majadahonda”, “Toledo”, “Dehesa de Amaniel”, “Retiro” and “Fuente Umbría”. The most tolerant clone was “Dehesa de Amaniel”, as its wilting values were below 5% during the two consecutive inoculation trials performed in Madrid. “Fuente Umbría”, tested over four consecutive years in Guadalajara and Palencia, was the Spanish clone with the most reliable tolerance level to O. novo-ulmi. The “Ademuz” and “Majadahonda” clones had the highest ornamental scores and are promising trees for use in urban environments and tree breeding for ornamental quality. These two genotypes showed a later bud burst phenology than the other U. minor clones, demonstrating suitability to areas with late frost events. The Spanish programme aims to substantially increase the range of tolerant native elms through new selections and crossings to gain a better understanding of the genetic basis of resistance.

Keywords: Dutch Elm Disease, Breeding, Plant Release, Resistance, Invasive Species

iForest 8 (2): 172-180 (2015) - doi: 10.3832/ifor1224-008
https://iforest.sisef.org/contents/?id=ifor1224-008

Commentaries & Perspectives: The elm, tree of milk and wine

Heybroek HM — 2014-08-13

Heybroek HM

THE ELM, TREE OF MILK AND WINE

Abstract: Elm has played an important role in European culture for thousands of years, in many roles, with regional variation. In material culture, its wood has assisted in hunting and warfare for over seven thousand years; but more importantly, its leaves and bark were semi-indispensible for the production of milk and meat, and served as an emergency food for humans. In the Mediterranean, elm was the main tool for the production of a good quality wine by providing support for the grapevine, and it helped feeding the cattle. These functions sometimes found an echo in the non-material culture. The fact that in Germanic genesis stories the first woman was created out of an elm (the man out of an ash), as well as a severe local taboo on the use of elm wood for skis, threatening the offender with a place in hell, seem both connected to the superior feeding value of this tree. In England and in parts of continental Europe most sacred trees were elms, sometimes performing female functions such as the production of babies. In the Mediterranean, however, the elm was seen as the male partner in the “marriage of the vine to the elm”, which was the celebrated system of viticulture. That image has been used by poets and politicians over the ages to praise the effects of human marriage, cooperation and interdependence. It even forms the core of the apocryphal Bible book “The Shepherd”, where it is seen as a symbol and example for a kind of symbiosis between the rich and the poor. - In conclusion, the ultimate origin of the English elm or “Atinia”, as well as its discovery is discussed, which appears to be a question of milk and wine.

Keywords: Ulmus, Viticulture, Fodder, Emergency Food, Non-material Culture, Cultivar “Atinia”, Cultivar “Arbia”

iForest 8 (2): 181-186 (2015) - doi: 10.3832/ifor1244-007
https://iforest.sisef.org/contents/?id=ifor1244-007

Review Papers: Dutch elm disease and elm bark beetles: a century of association

Santini A, Faccoli M — 2014-08-07

Santini A, Faccoli M

DUTCH ELM DISEASE AND ELM BARK BEETLES: A CENTURY OF ASSOCIATION

Abstract: Bark beetles of the genus Scolytus Geoffroy are the main vectors of the fungus Ophiostoma ulmi s.l., which causes the Dutch elm disease. The large and small elm bark beetles - S. scolytus (F.) and S. multistriatus (Marsham), respectively - are the most common and important species spreading the pathogen worldwide. The success of the pathogen-insect interactions is mainly due to the characteristic reproductive behavior of the elm bark beetles, which, however, largely depends on the occurrence of infected trees. During feeding activity on elm twigs, callow adults carrying pathogen conidia on their bodies contaminate healthy trees and facilitate pathogen development and movement within the wood vessels. Infected trees become then suitable for insect breeding in the stem bark. This well-known mutualistic association has devastating consequences for elm survival. Although much is known about insect-pathogen interactions and transmission mechanisms, many topics still deserve additional attention, as, for example, beetle systematic based on new molecular tools and morphological characters; selection of European elm clones based on disease avoidance; consequences of global warming on life-history of the three organisms (fungus-insect-tree) involved in the pathosystem; new problems resulting from the rapid increase of international trade among continents, leading to the accidental introduction of new vector species or new pathogen species or races, or to the introduction of new highly susceptible elm species in gardens and public parks. A holistic approach to tackle the problem is highly recommended, taking into account how these organisms interact with each other and the environment, and how their interactions could be modified in order to face one of the most destructive diseases ever known in plant pathology.

Keywords: Dutch Elm Disease, Elm Beetles, Scolytus-Ophiostoma Interactions, DED Cycle, Avoidance Mechanisms, Disease Escape, Resistance

iForest 8 (2): 126-134 (2015) - doi: 10.3832/ifor1231-008
https://iforest.sisef.org/contents/?id=ifor1231-008

Review Papers: Ulmus laevis in the Iberian Peninsula: a review of its ecology and conservation

2014-08-07

Venturas M, Fuentes-Utrilla P, López R, Perea R, Fernández V, Gascó A, Guzmán P, Li M, Rodríguez-Calcerrada J, Miranda E, Domínguez J, González-Gordaliza G, Zafra E, Fajardo-Alcántara M, Martín JA, Ennos R, Nanos N, Lucena JJ, Iglesias S, Collada C, Gil L

ULMUS LAEVIS IN THE IBERIAN PENINSULA: A REVIEW OF ITS ECOLOGY AND CONSERVATION

Abstract: European white elm (Ulmus laevis Pallas) populations are scarce, small and fragmented in the Iberian Peninsula. Due to these characteristics the indigenous status of the species in the region has been questioned, whilst the species’ role in Iberian riparian forest ecology has been neglected. Herein we review past studies regarding this species’ distribution and ecology in the Iberian Peninsula, with special emphasis on the establishment of conservation priorities. We first present a collection of palaeogeographic, historic and genetic data suggesting that the Iberian Peninsula was a glacial refuge for U. laevis. Secondly, we analyse U. laevis distribution in relation to soil physico- chemical properties and water availability in Spain. Following this, we focus on the reproductive biology of the species, and investigate the effect of masting and empty seed production on predation and regeneration establishment. Finally, based on this knowledge, we propose conservation policies for U. laevis in the Iberian Peninsula.

Keywords: Elm Conservation, Drought-stress Vulnerability, Root Iron Uptake, Population Genetics, Seed Dispersal, Seed Predation, Ulmus laevis’ Distribution

iForest 8 (2): 135-142 (2015) - doi: 10.3832/ifor1201-008
https://iforest.sisef.org/contents/?id=ifor1201-008

Review Papers: Implementing the dynamic conservation of elm genetic resources in Europe: case studies and perspectives

Collin E, Bozzano M — 2014-08-07

Collin E, Bozzano M

IMPLEMENTING THE DYNAMIC CONSERVATION OF ELM GENETIC RESOURCES IN EUROPE: CASE STUDIES AND PERSPECTIVES

Abstract: Many European countries have undertaken the static preservation of native elm genotypes in clone collections maintained ex situ. Less development has been devoted to the dynamic conservation of elm populations in situ. Case studies of elm conservation in France are given here as an illustration of methods employed at country level. We also briefly review the process used by the “European Forest Genetic Resources Programme” (EUFORGEN) to monitor elm dynamic conservation in a pan-European perspective. Dynamic conservation methods were promoted by EUFORGEN through leaflets, strategies, Technical Guidelines and the geo-referenced database EUFGIS on Dynamic Conservation Units (DCUs). Because the network of DCUs needs to be representative of the partitioning of adaptive diversity across the species distribution range, a GIS-aided approach has been developed to position DCUs in environmental zones and identify conservation gaps. The two DCUs of European white elm (Ulmus laevis Pall.) selected in riparian forests of two different climatic zones of France show that management oriented toward habitat protection is compatible with dynamic conservation, and that the species can still be conserved in situ in spite of Dutch Elm Disease (DED). Collaboration with habitat conservationists enabled the monitoring of losses to DED and the assessment of within-population diversity for flowering phenology. Collaboration with forest geneticists revealed that the diversity of the Garonne population was low, but that it contained rare DNA variants and adaptive traits. Since 1987, experimental restoration of countryside hedges has been carried out, using field elm clones (U. minor Mill.) selected from the French national collection and tested for lower susceptibility to the agent of DED in artificial inoculation tests. Such plantations can be viewed as a very dynamic form of conservation if they permit the local gene pool to be reinforced with trees able to reach sexual maturity and exchange pollen with elms in the neighborhood, hence contributing new genotypes that will be submitted to natural selection and provide fuel for ongoing adaptation processes. Initiatives assembling a large consortium of stakeholders, including habitat conservationists and hedge re-constructors, are needed to trigger new conservation projects.

Keywords: Elm, Ulmus minor, Dynamic Conservation, Population Genetics, Europe, France

iForest 8 (2): 143-148 (2015) - doi: 10.3832/ifor1206-008
https://iforest.sisef.org/contents/?id=ifor1206-008

Review Papers: Genomics of the Dutch elm disease pathosystem: are we there yet?

2014-08-07

Bernier L, Aoun M, Bouvet GF, Comeau A, Dufour J, Naruzawa ES, Nigg M, Plourde KV

GENOMICS OF THE DUTCH ELM DISEASE PATHOSYSTEM: ARE WE THERE YET?

Abstract: During the last decades, the development of ever more powerful genetic, molecular and omic approaches has provided plant pathologists with a wide array of experimental tools for elucidating the intricacies of plant-pathogen interactions and proposing new control strategies. In the case of the Dutch elm disease (DED) pathosystem, these tools have been applied for advancing knowledge of the host (Ulmus spp.) and the causal agents (Ophiostoma ulmi, O. novo-ulmi and O. himal-ulmi). Genetic and molecular analyses have led to the identification, cloning and characterization of a few genes that contribute to parasitic fitness in the pathogens. Quantitative PCR and high-throughput methods, such as expressed sequence tag analysis, have been used for measuring gene expression and identifying subsets of elm genes that are differentially expressed in the presence of O. novo-ulmi. These analyses have also helped identify genes that were differentially expressed in DED fungi grown under defined experimental conditions. Until recently, however, functional analysis of the DED fungi was hampered by the lack of protocols for efficient gene knockout and by the unavailability of a full genome sequence. While the selective inactivation of Ophiostoma genes by insertional mutagenesis remains a challenge, an alternative approach based on RNA interference is now available for down-regulating the expression of targeted genes. In 2013, the genome sequences of O. ulmi and O. novo-ulmi were publicly released. The ongoing annotation of these genomes should spark a new wave of interest in the DED pathosystem, as it should lead to the formal identification of genes modulating parasitic fitness. A better understanding of DED, however, also requires that omic approaches are applied to the study of the other biotic components of this pathosystem.

Keywords: Dutch Elm Disease, Ophiostoma spp., Genetic and Molecular Analyses, Gene Expression, RNA Interference

iForest 8 (2): 149-157 (2015) - doi: 10.3832/ifor1211-008
https://iforest.sisef.org/contents/?id=ifor1211-008

Research Articles: Comparison of commercial elm cultivars and promising unreleased Dutch clones for resistance to Ophiostoma novo-ulmi

Buiteveld J, Van Der Werf B, Hiemstra JA — 2014-08-07

Buiteveld J, Van Der Werf B, Hiemstra JA

COMPARISON OF COMMERCIAL ELM CULTIVARS AND PROMISING UNRELEASED DUTCH CLONES FOR RESISTANCE TO OPHIOSTOMA NOVO-ULMI

Abstract: Elms, and especially Ulmus × hollandica have been dominant and very much appreciated trees in cities and rural landscape for centuries in the Netherlands. As a result of two Dutch Elm Disease (DED) epidemics in the 20th century these trees largely disappeared from the landscape. Despite the introduction of new cultivars with increased levels of DED-resistance, by the end of the 20th century the elm had disappeared from the top 20 list of trees produced by Dutch nurseries. New cultivars with increased resistance to DED are used to a limited extent only. Apparently the lasting problems with DED in old cultivars has led to a lack of confidence in the resistance of these latest released cultivars among urban foresters and landscape managers. This paper reports on a study that aims at restoring the position of the elm as a street tree in the Netherlands by providing information on resistance to O. novo-ulmi causing DED of the currently available cultivars. All elm cultivars currently on the Dutch market were compared in an inoculation test. In 2007 a field experiment of 18 cultivars, one species and 10 non-released clones from the Dutch elm breeding program was established. Two cultivars were used as reference clones: “Commelin” (relatively susceptible) and “Lobel” (relatively resistant). In 2008 and 2009 the elms were stem-inoculated with Ophiostoma novo-ulmi and disease development was assessed throughout the summer and the following year. Clear differences in resistance to O. novo-ulmi were found between the cultivars, with “Columella”, “Sapporo Autumn Gold”’ and “Rebella” being highly resistant and significantly different from “Lobel” and “Regal”, “Urban”, “Belgica”, “Den Haag” and the U. laevis seedlings being the most susceptible and comparable to “Commelin”. The non-released clones performed comparable to “Lobel’”or even better. The ranking of the cultivars based on their level of resistance to O. novo-ulmi in this field test corresponds well with experience in urban green practice. Our conclusion is that there is a wide range of cultivars available with a good to excellent level of resistance. The available cultivars have a broad genetic base due to different parentage and use of exotic germplasm in the crossings. This broad genetic background may contribute to the stability of resistance in case new forms of the disease appear. The non-released clones performed well compared to the released cultivars and give good opportunities to further broaden the current range of cultivars on the Dutch and European market.

Keywords: DED-resistance, Elm Cultivars, Ulmus, Inoculation Test, Ophiostoma novo-ulmi

iForest 8 (2): 158-164 (2015) - doi: 10.3832/ifor1209-008
https://iforest.sisef.org/contents/?id=ifor1209-008

Research Articles: A model of shrub biomass accumulation as a tool to support management of Portuguese forests

2014-07-27

Botequim B, Zubizarreta-Gerendiain A, Garcia-Gonzalo J, Silva A, Marques S, Fernandes PM, Pereira JM, Tomé M

A MODEL OF SHRUB BIOMASS ACCUMULATION AS A TOOL TO SUPPORT MANAGEMENT OF PORTUGUESE FORESTS

Abstract: The evaluation of forest fuel loading is required by most fire management activities. However, the consideration of shrub biomass for forest planning purposes has been limited by the inability to predict its growth and accumulation. The main objective of this study was to model shrub biomass over time under a tree canopy to be able to include shrub management in fire risk mitigation plans. Data for this purpose was obtained from the 4th and 5th Portuguese National Forest Inventories. Five biologically realistic models were built to describe shrub biomass accumulation in Portuguese forests. The selected model indicates that maximum biomass is affected by stand basal area and the percentage of resprouting shrub species in the stand. Biomass growth rate was clearly affected by the regeneration strategies of shrubs in combination with climatic conditions (mean annual temperature). The model can be used in the accumulation form for initialization purposes or in one of the two alternative difference forms to project observed shrub biomass. The acquired ability to estimate shrub biomass facilitates its inclusion in forest growth models and simulators and will contribute to more accurate estimates of fire behaviour characteristics and stored carbon. This is instrumental to improve decision-making in forest management plans that integrate fire risk, namely to schedule understory fuel treatments.

Keywords: Shrub Growth, Understory Vegetation, Wildfire Risk, Fire Management, Forest Planning, Decision Making

iForest 8 (2): 114-125 (2015) - doi: 10.3832/ifor0931-008
https://iforest.sisef.org/contents/?id=ifor0931-008

Research Articles: Effect of the plantation age on the use of Eucalyptus stands by medium to large-sized wild mammals in south-eastern Brazil

Timo TP, Lyra-Jorge MC, Gheler-Costa C, Verdade LM — 2014-07-21

Timo TP, Lyra-Jorge MC, Gheler-Costa C, Verdade LM

EFFECT OF THE PLANTATION AGE ON THE USE OF EUCALYPTUS STANDS BY MEDIUM TO LARGE-SIZED WILD MAMMALS IN SOUTH-EASTERN BRAZIL

Abstract: In São Paulo State, in Southeastern Brazil, the Eucalyptus plantations have been replacing large areas which were formerly occupied by pastures used for livestock production. Such land use change may affect the habitat use by wildlife in these anthropic landscapes. In this region, the commercial Eucalyptus plantations of the paper and cellulose industry usually take from 6 to 7 years to be harvested. During its production cycle, the Eucalyptus stands vary from an open savanna-like environment just after plantation, when plants still resemble bushes, to a forest-like environment with densely distributed 18-meter high trees. Previous studies show that the Eucalyptus plantations in Southeastern Brazil are used by generalist species including medium and large sized mammals. However, the possible influence of such dramatic temporal environmental heterogeneity on the wildlife habitat use in Eucalyptus plantations is still unknown. In this study, which follows a classic stratified design, we evaluate the influence of the Eucalyptus stand age on the local patterns of distribution and abundance of middle to large-sized wild mammals. Our results show an increase not only in their species richness, but also in their frequency of occurrences along the commercial cycle of the Eucalyptus plantations with a steep decline in both before harvest. This pattern may be related to weed control practices which significantly reduce the understory vegetation, in especial at the end of the commercial cycle while preparing for harvest. Future studies should prioritize the possible variation on the trophic structure in the Eucalyptus plantations along commercial cycles as a response of wildlife friendly silvicultural/agricultural management practices.

Keywords: Forestry, Silvicultural Landscapes, Anthropic Environments, Wildlife, Temporal Heterogeneity

iForest 8 (2): 108-113 (2015) - doi: 10.3832/ifor1237-008
https://iforest.sisef.org/contents/?id=ifor1237-008

Review Papers: Design-based methodological advances to support national forest inventories: a review of recent proposals

Fattorini L — 2014-06-18

Fattorini L

DESIGN-BASED METHODOLOGICAL ADVANCES TO SUPPORT NATIONAL FOREST INVENTORIES: A REVIEW OF RECENT PROPOSALS

Abstract: The aim of this paper is to give an overview of some recent proposals to support national forest inventories. The reviewed literature is strictly of design- based nature, i.e., uncertainty only stems from the sampling scheme actually adopted in the survey, rather than being assumed or modeled as in model- based approaches. National forest inventories are viewed as two-phase sample surveys to estimate at the same occasion the extent of the continuous population of points constituting the forest cover and the total of a forest attribute (e.g., volume or biomass) in the discrete population of trees for several forest types and/or administrative districts. The first phase is performed from remote sensing imagery while the second phase is performed on the field, possibly adopting the information acquired in the first phase as auxiliary information. A novel methodology is adopted based on Monte Carlo integration methods, which leads to a very general estimation strategy. Some recent proposals are considered in which remote sensing information acquired in the first phase is used to assess some physical characteristics of non-forest resources, such as woodlots, tree-rows and isolated trees outside the forest without additional field work. Finally, a new proposal is discussed in which canopy height from laser scanning is adopted as auxiliary information to recover missing data occurring when some sampled points cannot be reached because of hazardous terrain.

Keywords: Two-phase Strategies, Aerial Information, Non-forest Resources, Missing Data, LiDAR, Calibration Weighting

iForest 8 (1): 6-11 (2015) - doi: 10.3832/ifor1239-007
https://iforest.sisef.org/contents/?id=ifor1239-007

Research Articles: Estimating changes in soil organic carbon storage due to land use changes using a modified calculation method

Li Y, Xia Y, Lei Y, Deng Y, Chen H, Sha L, Cao M, Deng X — 2014-06-17

Li Y, Xia Y, Lei Y, Deng Y, Chen H, Sha L, Cao M, Deng X

ESTIMATING CHANGES IN SOIL ORGANIC CARBON STORAGE DUE TO LAND USE CHANGES USING A MODIFIED CALCULATION METHOD

Abstract: Carbon sources and sinks have been widely scrutinized over the last ten years as a result of the Kyoto Protocol. In this paper we added a new concept (standardized reference depth, DSR) to the current calculation method in order to assess and compare the soil organic carbon (SOC) storage changes due to three major land use changes with a certain historical relationship (from primary rain forest to fallow land to natural secondary forest and finally to rubber plantations - Hevea brasiliensis) in a northern tropical ecosystem in southwest China. Over 30 years, the soil organic carbon storage did not decrease significantly with a land use change from primary rain forest to fallow land (approximately 10.3%). However, it did increase significantly (approximately 49.3%) due to conversions to natural secondary forest and rubber plantations (approximately 41.6%). In this region, the soil carbon sequestration at rubber plantations is similar to that of natural secondary forests. Compared with the modified method, the current method overestimated carbon storage on fallow land by 8.8% more than the actual storage (calculated reference depth of 13.9 cm, Dr - DSR = 13.9, without the reference depth standardization process), overestimated carbon storage at rubber plantations by 3.6% (calculated reference depth of 4.9 cm), and underestimated the natural secondary forest carbon storage by 6.4% (calculated reference depth of 9.7 cm). Thus, the modified process using the standardized reference depth for the current method is necessary for the evolution and comparison of soil carbon or other nutrient storage changes.

Keywords: Soil Organic Carbon Storage, Land Use Change, Modified Calculation Method, Rubber Plantation, Tropical Forest, Kyoto Protocol

iForest 8 (1): 45-52 (2015) - doi: 10.3832/ifor1151-007
https://iforest.sisef.org/contents/?id=ifor1151-007

Research Articles: Comparing multisource harmonized forest types mapping: a case study from central Italy

Vizzarri M, Chiavetta U, Chirici G, Garfì V, Bastrup-Birk A, Marchetti M — 2014-06-17

Vizzarri M, Chiavetta U, Chirici G, Garfì V, Bastrup-Birk A, Marchetti M

COMPARING MULTISOURCE HARMONIZED FOREST TYPES MAPPING: A CASE STUDY FROM CENTRAL ITALY

Abstract: The availability of common standardized geospatial information on composition, structure and distribution of forests is essential to support environmental actions, sustainable forest management and planning policies. Forest types maps are suitable tools for supporting both silvicultural and forest planning choices from local to global scale levels. For this reason local authorities may develop forest types maps independently, in which case a standardized/harmonized framework for their comparison and aggregation is essential. At the same time local forest types maps may not be directly related to pan-European forest resources assessments and classification systems. This paper presents results of the harmonization of four forest types maps available for central Italy. The process is based on a bottom-up approach aimed at maintaining the most detailed common nomenclature system across the different Regions. The final results, in terms of forest types area, are compared with several independent sources of information: (i) two forest maps, one developed at national level on the basis of the Corine Land Cover 2006, and one for high resolution forest / non forest classification developed at pan-European level; and (ii) two sample based inventories: the Italian National Forest Inventory (INFC) and the Italian Land Use Inventory (IUTI). The results show that the proposed bottom- up harmonization approach is a suitable tool to guarantee the integrity and homogeneity of local forest types nomenclature systems, and to integrate such local data with European standards.

Keywords: Forest Categories, Forest Types, Central Italy, Forest Area Estimation, Forest Nomenclature Systems, Forest Resources Classification, Forest Resources Mapping

iForest 8 (1): 59-66 (2015) - doi: 10.3832/ifor1133-007
https://iforest.sisef.org/contents/?id=ifor1133-007

Research Articles: Assessment of the protective function of forests against debris flows in a gorge of the Slovenian Alps

Fidej G, Mikoš M, Rugani T, Jež J, Kumelj Š, Diaci J — 2014-06-17

Fidej G, Mikoš M, Rugani T, Jež J, Kumelj Š, Diaci J

ASSESSMENT OF THE PROTECTIVE FUNCTION OF FORESTS AGAINST DEBRIS FLOWS IN A GORGE OF THE SLOVENIAN ALPS

Abstract: Protection forests play an important role in mitigating the influence of natural hazards. Despite the growing need for protective functions due to aging forests and increased risk of natural disturbances, active forest management has become increasingly uncommon across the Alps. Active management of protection forests can be facilitated by state subsidies. This requires an objective delineation of forests with a direct protection function and the development of silvicultural techniques that mitigate natural hazards. A study of protection efficiency of beech-dominated forests in the Soteska gorge in NW Slovenia, where a main state road and railway are at risk from debris flows and rockfall, was performed. We assessed the starting points of debris-flow hazard based on a small-scale geological survey of the terrain characteristics and a local debris flow susceptibility map. We applied the TopRunDF model for determination of the run-out zones. Forest structure data were obtained from 26 sample plots. A detailed description and delineation of forest stands was performed. The results showed that these forests play an important role in the protection of infrastructure. Forest protection efficiency can be improved by stand thinning for stability and careful planning of regeneration patches over time and space. In areas where silvicultural measures cannot provide sufficient protection, technical measures are needed. Since these forests have not been managed for several decades, natural disturbances (windthrow) are frequent. Research findings suggest that regular assessment and management of these beech-dominated protection forests are necessary, contrary to the current practice of non-management in protection forests in Slovenia.

Keywords: Protection Forest, Protection Function, Debris Flow, TopRunDF, Beech Forest

iForest 8 (1): 73-81 (2015) - doi: 10.3832/ifor0994-007
https://iforest.sisef.org/contents/?id=ifor0994-007

Research Articles: Nutrient accumulation and export in teak (Tectona grandis L.f.) plantations of Central America

2014-06-04

Fernández-Moya J, Murillo R, Portuguez E, Fallas JL, Ríos V, Kottman F, Verjans JM, Mata R, Alvarado A

NUTRIENT ACCUMULATION AND EXPORT IN TEAK (TECTONA GRANDIS L.F.) PLANTATIONS OF CENTRAL AMERICA

Abstract: In order to assess the nutrient sustainability of teak plantations, a study was conducted to measure the amount of nutrients accumulated by the trees and exported during wood harvest. Three teak plantations (28 stands of different age) were studied in Costa Rica and Panama to assess those questions. Nutrient and biomass accumulation and allocation in different tree components (bole, bark, branches and foliage) were measured in the best performing trees between 1 and 19 years of age. A stand of 150 teak trees ha-1 at age 19 would accumulate (kg ha-1) 405 N, 661 Ca, 182 K, 111 Mg, 33 P, 53 S, 9 Fe, 0.47 Mn, 0.22 Cu, 0.92 Zn, 1 B; whereas the expected nutrient export by timber harvest (bole and bark) is (kg ha-1) 220 N, 281 Ca, 88 K, 63 Mg, 23 P, 39 S, 6 Fe, 0.13 Mn, 0.10 Cu, 0.21 Zn, 0.40 B. Hence, teak nutrition should pay special attention to N and K, together with Ca the nutrients most accumulated by teak. In addition, P and B could also be limiting planted teak forest productivity due to their general soil deficiencies. Proposed models estimate the amount of nutrients removed from the site during timber harvests, information that can be used by plantation managers to avoid soil nutrient depletion, approaching sustainability in forest plantation management.

Keywords: Forest Nutrition, Planted Forests, Costa Rica, Panama, Sustainability, Forest Soils

iForest 8 (1): 33-44 (2015) - doi: 10.3832/ifor1089-007
https://iforest.sisef.org/contents/?id=ifor1089-007

Research Articles: Effect of size and surrounding forest vegetation on chemical properties of soil in forest gaps

Özcan M, Gökbulak F — 2014-06-04

Özcan M, Gökbulak F

EFFECT OF SIZE AND SURROUNDING FOREST VEGETATION ON CHEMICAL PROPERTIES OF SOIL IN FOREST GAPS

Abstract: Forest gaps have different microclimatic conditions as compared to the surrounding areas, depending on gap size and surrounding forest types and affecting the biological, chemical, physical, and hydrological processes in the forest openings. The objective of this study was to determine the effect of forest gap size and surrounding forest cover type (beech or mixed stands) on the soil of forest opening by analyzing several soil chemical soil properties (pH, electrical conductivity - EC, organic matter - OM, and nutrient content). The study was conducted in the Yuvacik watershed in Izmit (Turkey) and a total of 31 forest gaps of different size (1.44-37.33 ha) and elevations (848-1169 m a.s.l.) were studied. Gaps were divided into three groups with size 0-5 ha, 5-15 ha, and >15 ha. Results showed that forest gap size significantly affected all the investigated chemical properties of the soil, except for soil pH. As gap size increased, sodium (Na+) concentration in the soil decreased from 22.72 to 19.57 mg L-1 while potassium (K+) and magnesium (Mg+2) concentrations increased from 83.88 to 134.62 mg L-1 and from 59.46 to 123.96 mg L-1, respectively. Medium-sized gap soils had the lowest OM content, as well as the lowest calcium (Ca+2) and nitrogen (N+3) concentrations. Surrounding forest types significantly influenced soil chemical properties in the openings, except for EC, N+3, and phosphorus (P-PO4-3). Soils in the gaps surrounded by mixed forest had significantly lower pH but higher OM content, K+, Na+, Ca+2, and Mg+2 concentrations than soils in beech forest gaps.

Keywords: Forest Openings, Forest Ranges, Plant Nutrients, Soil Chemistry, Forest Soils

iForest 8 (1): 67-72 (2015) - doi: 10.3832/ifor0940-007
https://iforest.sisef.org/contents/?id=ifor0940-007

Technical Advances: Technical properties of beech wood from aged coppices in central Italy

Lo Monaco A, Calienno L, Pelosi C, Balletti F, Agresti G, Picchio R — 2014-06-04

Lo Monaco A, Calienno L, Pelosi C, Balletti F, Agresti G, Picchio R

TECHNICAL PROPERTIES OF BEECH WOOD FROM AGED COPPICES IN CENTRAL ITALY

Abstract: The aim of this study is to assess the features of timber from aged coppices in transition to high forests to provide a basis for their more efficient utilisation. The introduction of a territorial protection policy and improvements in the socio-economic conditions of people living in mountain areas have led to a transition towards less intensive use of forests, which has resulted in the conversion of beech coppices into transitional high forests. The suspension of cutting has produced so-called “aged coppices”, now at the stage of thinning. In this condition, high-quality timber is difficult to obtain and the wood supply is highly variable, making efficient processing during manufacture difficult. To investigate features of the timber, clear specimens from two sites, Prati di San Bartolomeo and Fontenova, were analysed. Physical and mechanical characteristics were as follows: dry density, 719 and 688 kg m-3; basic density, 585 and 560 kg m-3; radial shrinkage, 7.06 and 7.17%; tangential shrinkage, 12.43 and 11.72%; volumetric shrinkage, 19.05 and 18.51%; axial compression strength, 54.7 and 54.4 MPa; static bending strengths, 100.9 and 108.4 MPa; and Brinell hardness, 29.8 and 27.7 N mm-2. Wood colour was also measured, as it is an important parameter for the end users. It was assessed with the CIELAB system. The wood colour coordinates before ageing exhibited the following values: L*=82.06, a*=4.92, and b*=17.36. After 504 hours of light exposure, wood became darker (L* =68.99) and more yellow (a*=9.49; b*= 29.57). The results of this study highlight that beech wood from aged coppice in Central Italy shows interesting qualitative features, suggesting that it can be put to more profitable use than as firewood.

Keywords: Coppice in Transition, Density, Shrinkage, Mechanical Properties, Brinell Hardness, Wood Colour, Fagus sylvatica L., Central Italy

iForest 8 (1): 82-88 (2015) - doi: 10.3832/ifor1136-007
https://iforest.sisef.org/contents/?id=ifor1136-007

Research Articles: Evaluating short term simulations of a forest stand invaded by emerald ash borer

Levin-Nielsen A, Rieske LK — 2014-05-26

Levin-Nielsen A, Rieske LK

EVALUATING SHORT TERM SIMULATIONS OF A FOREST STAND INVADED BY EMERALD ASH BORER

Abstract: The invasive emerald ash borer (Agrilus planipennis - EAB) is causing rapid and widespread ash (Fraxinus spp.) mortality in eastern North America, has established populations near Moscow, Russia, and is threatening ash resources in Europe. Given the prevalence of susceptible hosts these post-invasion forests will clearly differ from their pre-invasion counterparts. Understanding these changes is key to mitigating the impacts of invasion and developing sound management strategies. We evaluated short term changes in a forest stand invaded by EAB, and examined if the southern variant of the Forest Vegetation Simulator (FVS) could accurately predict those changes. Through simulation, managers can gain a clearer understanding of how pest invasions impact and alter future forest dynamics. However, many simulators are designed to achieve long-term predictions and thus do not align with the short term changes associated with rapid EAB-induced ash mortality. Woody vegetation was surveyed in 2010 and used to project impacts of EAB invasion into 2012 by simulating a 50% ash mortality rate. The same plots were then re-surveyed in 2012, allowing us to evaluate: (1) changes in actual forest composition and structure; and (2) simulation accuracy. Within our forest stand, FVS accurately estimated short term changes in stem density and basal area parameters, thus demonstrating its value as a short-term simulator for EAB-induced changes within the southern region of the United States. EAB-induced ash mortality is quickly changing these forests and will ultimately alter how stakeholders manage their lands. We discuss the potential usefulness of FVS as a tool for aiding management decisions in response to EAB invasion.

Keywords: Ash, Forest Succession, Modeling, Forest Vegetation Simulator

iForest 8 (1): 19-24 (2015) - doi: 10.3832/ifor1163-007
https://iforest.sisef.org/contents/?id=ifor1163-007

Research Articles: Day and night respiration of three tree species in a temperate forest of northeastern China

Sun J, Guan D, Wu J, Jing Y, Yuan F, Wang A, Jin C — 2014-05-26

Sun J, Guan D, Wu J, Jing Y, Yuan F, Wang A, Jin C

DAY AND NIGHT RESPIRATION OF THREE TREE SPECIES IN A TEMPERATE FOREST OF NORTHEASTERN CHINA

Abstract: Leaf day respiration is one of the most fundamental plant physiological processes and plays a vital role in the plant carbon cycle. However, day respiration is inherently complex and difficult to measure. In this study, the Kok method and the Laisk method were used to measure leaf day respiration for the saplings of one evergreen conifer species (Pinus koraiensis) and two deciduous broadleaved species (Tilia amurensis and Fraxinus mandshurica) in a temperate forest. Results show that discrepancy between the corrected day respiration values estimated by the Kok and Laisk methods was only 4% for the three tree species. On average, day respiration was 55.9% and 52.6% lower compared to night respiration for the three tree species, as measured by the Kok and Laisk method, respectively. Day respiration of the evergreen conifer species estimated by the Kok method was 31.7% lower while that estimated by the Laisk method was 36.8% lower than that of the deciduous broadleaved species. Night respiration of the evergreen conifer trees was 40.7% lower than those of the deciduous broadleaved trees. Day respiration rate is positively correlated with night respiration rate. Notably, day respiration rate decreased with increased photosynthetic photon flux density, and even a small amount of light significantly inhibited leaf day respiration in all three species.

Keywords: Dark Respiration, Deciduous Broadleaved Tree, Evergreen Conifer Tree, Gross Primary Production, Light Inhibition, Temperate Forest

iForest 8 (1): 25-32 (2015) - doi: 10.3832/ifor0982-007
https://iforest.sisef.org/contents/?id=ifor0982-007

Editorials: Spatial information and participation in socio-ecological systems: experiences, tools and lessons learned for land-use planning

La Rosa D, Lorz C, König HJ, Fürst C — 2014-05-19

La Rosa D, Lorz C, König HJ, Fürst C

SPATIAL INFORMATION AND PARTICIPATION IN SOCIO-ECOLOGICAL SYSTEMS: EXPERIENCES, TOOLS AND LESSONS LEARNED FOR LAND-USE PLANNING

Abstract: The special issue “Spatial Information and participation of socio-ecological systems: experiences, tools and lessons learned for land-use planning”, focuses on a framework for information used in planning and participation processes for socio-ecological systems at different scales and contexts. The papers presented in the SI focus on three major questions: (1) How should we make use of spatial information for planning at different scales and contexts? (2) How should we share information among stakeholders and decision makers in land-use planning? (3) How can we communicate scientific knowledge to achieve effective decisions? The papers of this SI contribute original perspectives on how spatial information can be structured, used and communicated by/among different actors of land planning processes, creating more actionable scientific knowledge and effective related decision making.

Keywords: Participation, Land-use Planning, Stakeholders, Decision-making

iForest 7 (6): 349-352 (2014) - doi: 10.3832/ifor0093-007
https://iforest.sisef.org/contents/?id=ifor0093-007

Research Articles: Linking biomass production in short rotation coppice with soil protection and nature conservation

2014-05-19

Petzold R, Butler-Manning D, Feldwisch N, Glaser T, Schmidt PA, Denner M, Feger KH

LINKING BIOMASS PRODUCTION IN SHORT ROTATION COPPICE WITH SOIL PROTECTION AND NATURE CONSERVATION

Abstract: Biomass from short rotation coppice (SRC) plantations has attracted widespread attention as a component of new sustainable energy concepts. Nevertheless, as yet the surface area of SRC plantations in Europe is relatively low compared to other biomass producing land-use systems. This is somewhat incomprehensible because it has been shown that SRC systems also offer distinct ecological benefits. Therefore, greater consideration of the related ecosystem services should be incorporated into land-use planning processes. Presented in this study is a conceptual framework for the integration of soil protection and nature conservation into the spatial prioritization of areas suitable for SRC. This approach includes the development of a site-specific yield model and the identification and classification of criteria and indicators for both soil protection and nature conservation. The basic concept for planning procedures was established and tested for the State of Saxony (Germany). Existing constraints were identified, and could be attributed mainly to the availability of adequate information at different spatial scales. The regional-scale study emphasized the considerable biomass potential of SRC and the related synergy effects for soil protection and nature conservation. Future work should focus on the local (district, farm) and catchment scale and attempt to integrate additional aspects such as hydrological ecosystem services and carbon sequestration.

Keywords: Short Rotation Coppice, Yield Estimation, Soil Protection, Nature Conservation, Land Use Planning

iForest 7 (6): 353-362 (2014) - doi: 10.3832/ifor1168-007
https://iforest.sisef.org/contents/?id=ifor1168-007

Research Articles: Web GIS-based simulation of water fluxes in the Miyun catchment area

Gebel M, Meissner R, Halbfass S, Hagenau J, Duan S — 2014-05-19

Gebel M, Meissner R, Halbfass S, Hagenau J, Duan S

WEB GIS-BASED SIMULATION OF WATER FLUXES IN THE MIYUN CATCHMENT AREA

Abstract: Change of land use and agricultural management, combined with severe droughts during the last two decades, are the main reasons for a strong decrease of water quality and quantity in the Miyun reservoir (China). Due to semi-arid monsoon climate, episodic water fluxes have to be considered adequately in an integrated water resources management in the total catchment area. To get insight into runoff generation processes, sediment and nutrient source areas and transfer dynamics, a monitoring approach was established in the Miyun catchment area spanning from plot measurements with weighable gravitation lysimeters and in situ measurements to a subcatchment scale of approx. 10 km2. One of these subcatchments (Sheyuchuan) was selected to adapt the methodologies to the regional runoff pattern using the web GIS-based modeling tool STOFFBILANZ. Calibration of the daily runoff modeling is based on the lysimeter observations from Shixia station and runoff observations in Sheyuchuan subcatchment for the reference year 2011. Despite the fact that the climatic water balance in the region is negative, the precipitation event on 24 July 2011 with a rainfall of 107 mm caused a significant leachate at the lysimeter. The daily modeling for the lysimeter core by the FAO-ETc-adj approach showed a similar deep percolation and a similar distribution of evapotranspiration for the year considered. In the next step, the calibrated model was applied to the subcatchment Sheyuchuan to compare the results of direct runoff and groundwater runoff (deep percolation) with the runoff observations at the weir. Deep percolation was extremely small (1.7 mm yr-1), and direct runoff was 26.9 mm yr-1 in 2011. In comparison to the monitoring results at the weir, a disagreement in the quantity of runoff was found between the observation on the one hand and the simulation on the other hand, which can be explained by water storage in reservoirs for irrigation purposes. Additionally, the water fluxes in the total catchment area were simulated at meso-scale, obtaining a good correlation with observed values.

Keywords: Bottom-up, Direct Runoff, Lysimeter, Meso Scale, Miyun, Model, Percolation

iForest 7 (6): 363-371 (2014) - doi: 10.3832/ifor1169-007
https://iforest.sisef.org/contents/?id=ifor1169-007

Research Articles: Future land use and food security scenarios for the Guyuan district of remote western China

Zhen L, Deng X, Wei Y, Jiang Q, Lin Y, Helming K, Wang C, König HJ, Hu J — 2014-05-19

Zhen L, Deng X, Wei Y, Jiang Q, Lin Y, Helming K, Wang C, König HJ, Hu J

FUTURE LAND USE AND FOOD SECURITY SCENARIOS FOR THE GUYUAN DISTRICT OF REMOTE WESTERN CHINA

Abstract: Government policy is a major human factor that causes changes in land use. Thus, simulating the dynamics of land-use systems provides important information to support decisions on land management and land-use planning, and to analyze and quantify the consequences of policies. In the present study, we predicted land-use changes and their potential impacts on food security in the environmentally fragile Guyuan District, in the Ningxia Hui Autonomous Region of north-central China, under the influence of a program to convert sloping agricultural land to conservation uses. Baseline and conservation policy scenarios (2005 to 2020) were developed based on input from local stakeholders and expert knowledge. For the baseline and conservation policies, we formulated high-, moderate-, and low-growth scenarios, analyzed the driving mechanisms responsible for the land-use dynamics, and then applied a previously developed "dynamics of land systems" model to simulate changes in land uses based on the driving mechanisms. We found that spatially explicit policies can promote the conversion of land to more sustainable uses; however, decreasing the amount of agricultural and urban land and increasing grassland and forest cover will increase the risk of grain shortages, and the effect will be more severe under the conservation and high-growth scenarios than under the baseline and low-growth scenarios. The Guyuan case study suggests that, during the next decade, important trade-offs between environmental conservation and food security will inevitably occur. Future land-use decisions should carefully consider the balance between land resource conservation, agricultural production, and urban expansion.

Keywords: Land-use Patterns, Scenario Analysis, Dynamics of Land Systems Modeling, Food Security, Guyuan District, North-central China

iForest 7 (6): 372-384 (2014) - doi: 10.3832/ifor1170-007
https://iforest.sisef.org/contents/?id=ifor1170-007

Research Articles: Green oriented urban development for urban ecosystem services provision in a medium sized city in southern Italy

Martinico F, La Rosa D, Privetera R — 2014-05-19

Martinico F, La Rosa D, Privetera R

GREEN ORIENTED URBAN DEVELOPMENT FOR URBAN ECOSYSTEM SERVICES PROVISION IN A MEDIUM SIZED CITY IN SOUTHERN ITALY

Abstract: In southern Italy many cities are characterized by a lack of public urban greenspaces. Non-urbanized areas in these cities are suffering from surrounding urbanization pressures. These areas still provide important ecosystem services even if they are limited in size, highly fragmented and often neglected by local planning. New planning strategies are needed in order to protect and enhance the provision of ecosystem services delivered by existing Non-Urbanized areas, but municipalities usually have limited funds for acquiring public green areas via land expropriations. At the same time, requests for new urban development are still considerable. Consequently, it is not realistic to propose strategies for green areas that do not include new developments. The paper illustrates a strategy for a Green Oriented Urban Development (GOUD) that has been applied for the Master Plan of Catania, a medium sized city in Sicily (southern Italy). The strategy includes a limited amount of developments as well as new greenspaces in selected areas (Resource Zones), through the transfer of property and development rights between the municipality and developers. The strategy will allow to enhance the provision of ecosystem services, especially cultural services (thanks to a dramatic increase of accessibility to new greenspaces), regulating services (through climate regulation by new green land covers) and provisioning services such as urban agricultural products. Results show that it is possible to improve urban ecosystem services creating a more liveable and healthy urban environment at reduced cost for the municipal administrations.

Keywords: Urban Development, Ecosystem Services, Urban Planning

iForest 7 (6): 385-395 (2014) - doi: 10.3832/ifor1171-007
https://iforest.sisef.org/contents/?id=ifor1171-007

Technical Notes: The feasibility of implementing cross-border land-use management strategies: a report from three Upper Silesian Euroregions

Spyra M — 2014-05-19

Spyra M

THE FEASIBILITY OF IMPLEMENTING CROSS-BORDER LAND-USE MANAGEMENT STRATEGIES: A REPORT FROM THREE UPPER SILESIAN EUROREGIONS

Abstract: This paper presents selected comments concerning land-use management strategies for three Czech-Polish Euroregions: Pradziad, Silesia and Cieszyn Silesia. These Euroregions comprise part of the Upper Silesia cross-border region. The main body of this study was conducted by formulating a set of questions concerning land-use strategies in the cross-border Czech-Polish Euroregions and interviewing management representatives of each Euroregion. The first section of this study concerned the need for such strategies, threats to their implementation and their content. The second section described possible methods for implementing Euroregion land-use strategies after their preparation. It is argued that Euroregion land-use management strategies should reflect such aspects as the further development of the Euroregion as a cross-border institution and should include selected issues regarding economic development and the natural environment. There are selected threats to implementing land-use strategies, such as a lack of enthusiasm among Euroregion members, the limitations of the 2014-2020 European Union budget and difficulties in achieving a single Czech-Polish development vision. Moreover, the importance of adequate Czech-Polish borderland planning tools and the role of citizens in Euroregion development are emphasised. The utility of a Euroregion scale for regional and national land-use management is discussed, using the example of the Upper Silesia cross-border region. The connection of the study results with regional land-use norms is explored, incorporating current strategic documents concerning the Czech-Polish borderland and existing legislation from both sides of the border. Some conclusions concerning appropriate cross-border landscapes land-use planning tools are outlined.

Keywords: Czech-Polish Borderland, Upper Silesia, Euroregion, Cross-border Land-use Management Strategy

iForest 7 (6): 396-402 (2014) - doi: 10.3832/ifor1248-007
https://iforest.sisef.org/contents/?id=ifor1248-007

Research Articles: Confronting international research topics with stakeholders on multifunctional land use: the case of Inner Mongolia, China

2014-05-19

König HJ, Podhora A, Helming K, Zhen L, Wang C, Wübbeke J, Baumeister T, Du B, Yan H

CONFRONTING INTERNATIONAL RESEARCH TOPICS WITH STAKEHOLDERS ON MULTIFUNCTIONAL LAND USE: THE CASE OF INNER MONGOLIA, CHINA

Abstract: The established pattern of land use in the Inner Mongolia Autonomous Region is being challenged by China’s rapid overall economic transition. The provision of required land-related functions and services is subject to land management decision making. Scientific research can offer substantial support for this decision making by providing evidence of the interaction between land management and land function services. This paper’s objective was to identify the most important land use functions and services from a local perspective and to compare these functions and services with the land-related research topics addressed in the scientific literature. For this purpose, we conducted a workshop with local stakeholders (land use decision makers) in the West Ujimqin Banner (Inner Mongolia) as a specific case study and performed a comprehensive survey of the Inner Mongolian land use research published in international scientific journals. Our analysis indicated that the stakeholders assigned particular importance to social land use functions, such as jobs, as well as environmental land use functions and ecosystem processes. In contrast, the research topics were primarily concerned with natural science. We discussed possible shortcomings in the research agenda by emphasising and contrasting local stakeholder perspectives with the research topics and concluded that without bottom-up stakeholder participation, there would be a mismatch between the research interests of land use scientists and the needs of stakeholders. Future research that can contribute to local policy making with the aim of meeting the objectives of a multifunctional land use concept is required.

Keywords: Land Use, Decision Making, Research Needs, Science-policy Interface

iForest 7 (6): 403-413 (2014) - doi: 10.3832/ifor1172-007
https://iforest.sisef.org/contents/?id=ifor1172-007

Research Articles: Public participation in sustainable forestry: the case of forest planning in Slovakia

Sarvašová Z, Dobšinská Z, Šálka J — 2014-05-19

Sarvašová Z, Dobšinská Z, Šálka J

PUBLIC PARTICIPATION IN SUSTAINABLE FORESTRY: THE CASE OF FOREST PLANNING IN SLOVAKIA

Abstract: Public participation is considered to be an important element of democracy. The purpose of this paper is to evaluate participatory approaches in the formulation processes of forest strategic documents and forest management plans in Slovakia. In order to present the context in which the public participation in forestry is applied, we are describing the rules according to national forest law. The nation-wide example is presented for the case of the National Forest Program formulation, where the scope of the forest management units is covered by the process of Forest Management Plans elaboration and adoption. The empirical findings from forest authorities’ data show that participation is still very formal. The most common actors are public authorities represented by their official representatives and the most active actors besides forest owners or managers are environmental interest groups. To strengthen the participatory process in sustainable forestry planning, not only changes in legislation are needed but also an increase in public awareness concerning the significance of forestry resources.

Keywords: Participatory Approaches, Forest Management Planning, National Forest Program, Evaluation Of Participation Process

iForest 7 (6): 414-422 (2014) - doi: 10.3832/ifor1174-007
https://iforest.sisef.org/contents/?id=ifor1174-007

Research Articles: How do urban dwellers react to potential landscape changes in recreation areas? A case study with particular focus on the introduction of dendromass in the Hamburg Metropolitan Region

Boll T, von Haaren C, Albert C — 2014-05-19

Boll T, von Haaren C, Albert C

HOW DO URBAN DWELLERS REACT TO POTENTIAL LANDSCAPE CHANGES IN RECREATION AREAS? A CASE STUDY WITH PARTICULAR FOCUS ON THE INTRODUCTION OF DENDROMASS IN THE HAMBURG METROPOLITAN REGION

Abstract: Recently, many German regions have seen dramatic landscape changes in agricultural areas due to increasing cultivation of bioenergy crops. Especially in regions that are economically dependent on income from recreational use, this development faces opposition by tourist stakeholders, local inhabitants and recreationists. In the future tall bioenergy plants like maize could be replaced by even taller short rotation coppice plantations of willow and poplar. This development raises the question of how people perceive landscape changes and if perceptions are influenced by the landscape where they take place. We surveyed urban residents in the city of Hamburg (n= 400) to see how they perceive potential landscape changes in four recreation areas with different landscape structures in the vicinity of Hamburg (Lüneburg Heath, Harburg Hills, Elbe Marshes and Altes Land). The survey showed that people rated changes significantly different, depending on the specific landscape type of the recreation areas. The survey did not show a clear general preference for reducing or increasing forests. However, the landscape character of each recreation area had a strong influence on the acceptance of landscape changes by planting forests, hedges, and shrubs. People showed a significantly higher negative reaction towards more forests in open landscapes characterized by heath and meadows than in landscapes with a higher share of forests and fields. Interestingly, the introduction of hedges and shrubs was evaluated differently from the introduction of forests depending on the type of open landscape. People preferred the introduction of hedges and shrubs in the landscape rich in meadows and pastures while they rejected the introduction of hedges and shrubs in a historic cultural landscape rich in heathland. In view of these results we recommend that the landscape character and the cultivation system are considered in the assessment and determination of potential short rotation coppice production sites. This may considerably increase the acceptability of dendromass cultivation for energy purposes.

Keywords: Landscape Changes, Recreation, Landscape Character, Visual Landscape, Dendromass, Short Rotation Coppice, Agriculture, Forestry

iForest 7 (6): 423-433 (2014) - doi: 10.3832/ifor1173-007
https://iforest.sisef.org/contents/?id=ifor1173-007

Research Articles: Communicating spatial planning decisions at the landscape and farm level with landscape visualization

Warren-Kretzschmar B, Von Haaren C — 2014-05-19

Warren-Kretzschmar B, Von Haaren C

COMMUNICATING SPATIAL PLANNING DECISIONS AT THE LANDSCAPE AND FARM LEVEL WITH LANDSCAPE VISUALIZATION

Abstract: Landscape visualizations have the potential to support participatory environmental planning at different spatial scales and decision levels from international to farm level. However, it is yet unclear what specific demands are relevant for visualization on the different decision levels. In this context more knowledge is needed about visualization objectives and the respective tasks, intended effects and suitable techniques for the specific levels. Especially the farm level has been neglected in research, although farmers make many decisions that affects public interests in the visual landscape. Farmers need to communicate these decisions to the public in an understandable way. The question of how visualization can support participation in the planning process at the municipal level is examined in this paper by drawing on the findings of the Interactive Landscape Plan Koenigslutter, Germany (IALP) about the preferences and reactions of citizens to visualizations used in the landscape planning process at the local decision level. On this basis, we examined the applicability and differences of the findings for the farm level. Furthermore, in order to explore visualization opportunities at the farm scale, the farm management system MANUELA was used as an example of an information platform that could serve as a basis for farm scale visualizations. By transferring landscape planning results to the farm level, we developed recommentations about the application of visualization, intended effects and appropriate techniques at the farm scale. The general findings for the municipal level show that visualization can improve participation by providing participants with a common image of the planning proposals for discussion and collaborative decisions. Different visualization methods offer different capabilities for supporting participation in the different planning phases. At the farm scale, 2D visualizations and diagrams are often sufficient to communicate information to customers about farm performance for providing ecosystem services. They may consist of maps and supporting information that is easily generated from GIS data. However, for a higher (more interactive) level of communication and participation activities, such as discussions with affected neighbors about land use changes or the integration of citizens’ proposals, more sophisticated visualization techniques would be required. Visualization techniques are needed that farmers can use to easily simulate visual impacts of land use changes at the landscape scale.

Keywords: Landscape Planning, Participatory Planning, Landscape Visualization, Farm Scale, Ecosystem Services, MANUELA

iForest 7 (6): 434-442 (2014) - doi: 10.3832/ifor1175-007
https://iforest.sisef.org/contents/?id=ifor1175-007

Research Articles: Controlled-release fertilizers combined with Pseudomonas fluorescens rhizobacteria inoculum improve growth in Pinus halepensis seedlings

Dominguez-Nuñez JA, Delgado-Alvez D, Berrocal-Lobo M, Anriquez A, Albanesi A — 2014-05-12

Dominguez-Nuñez JA, Delgado-Alvez D, Berrocal-Lobo M, Anriquez A, Albanesi A

CONTROLLED-RELEASE FERTILIZERS COMBINED WITH PSEUDOMONAS FLUORESCENS RHIZOBACTERIA INOCULUM IMPROVE GROWTH IN PINUS HALEPENSIS SEEDLINGS

Abstract: Pinus halepensis seedlings are currently used to regenerate arid Mediterranean regions. Optimized methods for seedling fertilization in nurseries improve plant growth and are essential for successful reforestation. Previously, we showed that inoculation of P. halepensis seedlings with Pseudomonas fluorescens CECT 844 rhizobacteria improved plant growth and N uptake. The aim of this study was to determine the physiological and morphological response of P. halepensis seedlings to a combined treatment including controlled-release fertilization and inoculation with the rhizobacterium P. fluorescens. P. halepensis seedlings were grown in a nursery under well-watered conditions and were fertilized (F), inoculated with P. fluorescens (Ps) or fertilized and inoculated (F x Ps). Growth and water parameters (osmotic potential at both full and zero turgor and modulus of elasticity) were measured in seedlings under each treatment. The total N, P, K, Ca, Mg and Fe contents and concentrations in seedling roots and shoots were also measured. Finally, root growth potential was estimated. F x Ps increased both seedling growth and nutrient uptake compared with the independent treatments. Interestingly, amendment with rhizobacteria had a slight negative effect on osmotic potential and P uptake, which was lessened by combining Ps with F. The present work shows that F x Ps is highly efficient for improving the quality of forest seedlings in nurseries. As such, F x Ps represents a potential alternative treatment that could reduce contaminant emissions and increase microbiota soil regeneration in degraded soils.

Keywords: Controlled-release Fertilization, Rhizobacteria, Pinus halepensis, Water Parameters, Mineral Nutrition, Nursery, Root Growth Potential, Osmotic Potential

iForest 8 (1): 12-18 (2015) - doi: 10.3832/ifor1110-007
https://iforest.sisef.org/contents/?id=ifor1110-007

Research Articles: Site quality assessment of degraded Quercus frainetto stands in central Greece

Kitikidou K, Milios E, Tsirekis E, Pipinis E, Stampoulidis A — 2014-05-12

Kitikidou K, Milios E, Tsirekis E, Pipinis E, Stampoulidis A

SITE QUALITY ASSESSMENT OF DEGRADED QUERCUS FRAINETTO STANDS IN CENTRAL GREECE

Abstract: The potential yield of a site is measured by site index, which is defined as the dominant height of a stand at a base age. A site index model for site quality assessment of Quercus frainetto (Hungarian oak) stands in central Greece was developed using a base age of 50 years. Data were collected from 39 temporary sample plots of 10 x 10 m. Linear regression models widely used in site index studies were fitted to height-age data. The adjusted coefficient of determination (R2adj), root mean square error (RMSE), bias, coefficient of determination for the prediction (R2pr) and residual plots were used for the choice of the best-fitting model. The best model was H = -0.231+0.251A-0.001A2, where H is the predicted height at age A. The guide curve method was adopted in constructing the sites curves, with the chosen model as the guide curve. Based on this curve, the study area was divided into three site quality classes (I to III), with class I representing the best and class III the poorest. Also, the presence of a Simpson’s paradox in these analyses is discussed. The results showed that a 50-year-old stand in the study area attained an average dominant height of about 11, 8 and 6 m on site quality classes I, II and III, respectively. The Hungarian oak stands of the present study can be considered very low productivity stands.

Keywords: Guide Curve Method, Hungarian Oak, Simpson’s Paradox, Site Quality

iForest 8 (1): 53-58 (2015) - doi: 10.3832/ifor1069-007
https://iforest.sisef.org/contents/?id=ifor1069-007

Research Articles: The impacts of a wildfire on hunting demand: a case study of a Mediterranean ecosystem

Papaspyropoulos KG, Sokos CK, Birtsas PK — 2014-05-12

Papaspyropoulos KG, Sokos CK, Birtsas PK

THE IMPACTS OF A WILDFIRE ON HUNTING DEMAND: A CASE STUDY OF A MEDITERRANEAN ECOSYSTEM

Abstract: The present study attempted to estimate the socioeconomic impacts on hunting demand caused by a 2006 wildfire on a typical Mediterranean ecosystem in Greece (Kassandra peninsula). A questionnaire administered to a sample of local hunters was used to test the hypothesis that the wildfire and the consequent hunting ban, which was used by the Greek Forest Service as a measure for wildlife protection, posed a significant impact on the demand of hunters for hunting licenses and hunting trips. Using questionnaires as a source of information it was assessed what these impacts meant for the economy, either on local, or national scale, by estimating the income elasticity of demand for hunting licenses in the area of Kassandra and the expenses for hunting excursions before and after wildfire. It was observed that hunters attempted to preserve their activity despite the excessive hunting restrictions. Implications for hunting management and policy decision making were examined.

Keywords: Elasticity of Demand, Hunters, Hunting Management, Wildfires, Greece

iForest 8 (1): 95-100 (2015) - doi: 10.3832/ifor0799-007
https://iforest.sisef.org/contents/?id=ifor0799-007

Research Articles: Calibration assessment of forest flammability potential in Italy

Corona P, Ferrari B, Cartisano R, Barbati A — 2014-05-07

Corona P, Ferrari B, Cartisano R, Barbati A

CALIBRATION ASSESSMENT OF FOREST FLAMMABILITY POTENTIAL IN ITALY

Abstract: Fuel flammability is defined as the relative ease with which a fuel will ignite and burn with a flame; different forest types have different intrinsic “baseline” flammabilities, depending on the susceptibility to burn of the main tree species that build up the forest cover. In this perspective, we apply a forest-type based approach to classify and map the flammability level of the forests in Italy. Baseline forest type-based flammability values provided at European level have been assigned to a national forest types map, derived from Corine Land Cover 2006; flammability values have been then further calibrated against the Burned Area Selection Ratio, a measure of the actual incidence of wildfires among different forest types. Accordingly, a calibrated flammability index was derived by simple linear regression, so that predicted flammability more accurately reflects observed fire incidence among different forest types in Italy. Findings show that the flammability of forest types ranges from low to high: on average, the 17% of the forest cover has medium to high flammability, with wide regional variability; notably, in four Regions (Sardegna, Sicilia, Puglia, Calabria) over one third of total forest area has medium to high flammability. Large scale mapping of forest flammability is crucial to define long-term priorities among forest areas as to how to distribute fire management effort: areas falling into medium to high flammability classes should be given priority for implementing fuel management treatments in order to mitigate fire hazard from the stand to the landscape scale.

Keywords: Fuel Flammability, Fire Hazard, European Forest Types, Burned Area Selection Ratio, Fire Management

iForest 7 (5): 300-305 (2014) - doi: 10.3832/ifor1123-007
https://iforest.sisef.org/contents/?id=ifor1123-007

Technical Advances: Thermal canopy photography in forestry - an alternative to optical cover photography

Nölke N, Beckschäfer P, Kleinn C — 2014-05-07

Nölke N, Beckschäfer P, Kleinn C

THERMAL CANOPY PHOTOGRAPHY IN FORESTRY - AN ALTERNATIVE TO OPTICAL COVER PHOTOGRAPHY

Abstract: Hemispherical canopy photography is a widely used technique to observe crown-related forest variables. However, standardization of this technique remains challenging, as exposure and threshold settings continue to constitute the main sources of variation of such photographs. This paper, therefore, presents a new method to overcome standardization issues by using thermal canopy photography. With a thermal camera, images are produced which are not critically limited in their dynamic range so that photographic exposure becomes irrelevant. Moreover, the high temperature contrast between “sky” and “non-sky”, resulting from extreme low sky temperatures, facilitates the unambiguous selection of a threshold which separates “sky” from “non-sky” pixels. For our comparison, we have taken canopy images with a high-resolution thermal camera (VarioCam hr head [Infratec, Dresden, Germany]) and an optical camera (Nikon D70s). The correlation of canopy closure values derived from the image pairs was r = 0.98. Our findings thus show that thermal canopy photography is a promising and simple to use alternative to optical canopy photography, because it limits possible sources of variability, since exposure settings and threshold definition cease to be an issue.

Keywords: Hemispherical Photographs, Exposure, Thresholding, Thermal Images, Canopy Structure

iForest 8 (1): 1-5 (2015) - doi: 10.3832/ifor1129-007
https://iforest.sisef.org/contents/?id=ifor1129-007

Technical Notes: Historical utilization of wood in southeastern Moravia (Czech Republic)

Filková V, Kolár T, Rybníček M, Gryc V, Vavrčík H, Jurčík J — 2014-05-07

Filková V, Kolár T, Rybníček M, Gryc V, Vavrčík H, Jurčík J

HISTORICAL UTILIZATION OF WOOD IN SOUTHEASTERN MORAVIA (CZECH REPUBLIC)

Abstract: In the present study, anatomical features were used to identify tree species chosen to craft farming tools from the 19th and first half of the 20th century preserved in specimen inventories of the open-air museum in Strážnice, south-eastern Moravia (Czech Republic). In total, 701 samples from 337 historical farming tools were obtained from museum specimens. The samples were identified at micro- or macroscopic levels, or both. Results indicated local people used floodplain forest wood to construct farming tools in the study region. Nineteen wood species were identified; from this total, those with higher densities and better mechanical properties were used to manufacture tools, and included predominantly beech, oak, and ash. Softwood species, with lower densities were mainly used for chiseled out implements. We hypothesized regional forest species composition played an essential role in woody species choice, however the species also possessed appropriate properties. Cultivated tree species, such as fruit trees, were employed to create common objects; however, currently, these species are typically applied for special purposes. We concluded an increased number of species were employed in the past for utilitarian purposes, including tree species grown outside local forest boundaries, including cultivated fruit tree species; and species were utilized with good, although perhaps tacit, knowledge of their properties.

Keywords: Farming Tools, Forest Species Composition, Open-air Museum, South-eastern Moravia, Wood Identification

iForest 8 (1): 101-107 (2015) - doi: 10.3832/ifor1091-007
https://iforest.sisef.org/contents/?id=ifor1091-007

Research Articles: Four decades of forest succession in the oak-dominated forest reserves in Slovakia

Saniga M, Balanda M, Kucbel S, Pittner J — 2014-04-17

Saniga M, Balanda M, Kucbel S, Pittner J

FOUR DECADES OF FOREST SUCCESSION IN THE OAK-DOMINATED FOREST RESERVES IN SLOVAKIA

Abstract: The study analyzes biodiversity, production and recovery processes in the natural oak-dominated forests in three protected areas in time span of four decades after the cessation of human impact. In each forest reserve, we established three permanent research plots of 0.5 ha, which were monitored regularly every 10 years. The obtained results confirmed an expected decrease of oak in all investigated areas, regardless of the level of past human intervention. Growth rates of oak stem density were negative in all reserves and ranged from -0.7% yr-1 (Kašivárová) to -2.1% yr-1 (Bujanov). A typical rotated-sigmoid diameter structure was confirmed during the whole observed period only in the reserve Boky. The moderate affected reserve (Kašivárová) showed a bimodal pattern and the most affected reserve (Bujanov) revealed the typical unimodal distribution. Considering spatial diversity, the recorded structure of investigated forests closely corresponds with the relative level of past intervention. In Boky, the most differentiated structure was reflected in the highest long-term mean stem density (890 ± 151 ha-1) and the lowest basal area and growing stock (36.5 ± 1.4 m2 ha-1 and 284 ± 22 m3 ha-1, respectively). The past-affected reserves reached higher values of basic stand parameters. In Kašivárová and Bujanov, the average basal area (36.5 and 44 m2 ha-1, respectively) and growing stock (284 and 518 m3 ha-1, respectively) correlated negatively with the level of structural heterogeneity, while the stem number revealed a positive correlation. We observed a continuous increase of deadwood volume and dead to live wood ratio. The recorded long-term volume of deadwood (43-128 m3 ha-1) and deadwood proportion (151-28%) tended to be higher in the past-affected reserves. The convergence towards the rotated-sigmoid distribution in both reserves with past human impact was recorded. Considering the vertical structure, the most dynamic changes were observed in the lower and middle layer. Moreover, the substitution of the light-demanding oak by shade-tolerant species (beech, hornbeam) was recorded. The intensity of substitution directly reflected the intensity of structure modification in the past. Our results suggest that the process of forest recovery and oak loss significantly depends on the level of past human intervention.

Keywords: Oak Decline, Past Human Impact, Recovery, Forest Reserve, Quercus petraea L

iForest 7 (5): 324-332 (2014) - doi: 10.3832/ifor0996-007
https://iforest.sisef.org/contents/?id=ifor0996-007