iForest - Biogeosciences and Forestry

Research Articles: Bioaccumulation of long-term atmospheric heavy metal pollution within the Carpathian arch: monumental trees and their leaves memoir

Vasile D, Enescu R, Apafaian A, Coman S, Scarlatescu V, Crisan V — 2024-11-27

Vasile D, Enescu R, Apafaian A, Coman S, Scarlatescu V, Crisan V

BIOACCUMULATION OF LONG-TERM ATMOSPHERIC HEAVY METAL POLLUTION WITHIN THE CARPATHIAN ARCH: MONUMENTAL TREES AND THEIR LEAVES MEMOIR

Abstract: Atmospheric pollution is a major problem in urban environments. Pollutants with various sizes of particulate matter result from long-term anthropogenic sources, including industrial emissions and the combustion of fossil fuels by vehicles and commercial and residential buildings. Pollutants affect both humans and green areas. Trees are good indicators of pollution due to their longevity, easy identification, and geographical distribution in urban areas. Recently, due to climate change, all EU member states have agreed to measure heavy metal pollution in urban areas using plants as bioindicators. This study aimed to analyze heavy metal concentrations (Pb, Cd, Mn, Fe, Cu, Zn) in the leaves of monumental trees (both evergreen coniferous and deciduous) in the Carpathian Arch. Leaf samples were collected in the summer of 2022 from 37 specimens across 12 sites in nine counties - Alba, Brasov, Harghita, Mures, Sibiu, Satu Mare, Bistrita Nasaud, Maramures, and Cluj. The leaf heavy metal contents correlated with a low level of atmospheric pollution. Of the six heavy metals analyzed, only four were highly accumulated in the leaf samples and exceeded the toxicity threshold. Of the nine counties sampled, heavy metal pollution above the toxicity threshold was detected only in two sites - the city of Baia Mare, Maramures county (Zn and Cd), and the city of Cluj-Napoca, Cluj county (Fe, Zn, Cd, and Cu). The response of the tree species to changes in atmospheric heavy-metal concentrations confirmed that trees are suitable bioindicators of air pollution in urban areas. Monumental trees can also be used for environmental restoration and to promote sustainable urban development, decrease pollution, and increase urban environmental health.

Keywords: Atmosphere Pollution, Urban Environments, Heavy Metals, Monumental Trees, Samples

iForest 17 (6): 370-377 (2024) - doi: 10.3832/ifor4611-017
https://iforest.sisef.org/contents/?id=ifor4611-017

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