iForest - Biogeosciences and Forestry
*

Post-fire recovery of the plant community in Pinus brutia forests: active vs. indirect restoration techniques after salvage logging

iForest - Biogeosciences and Forestry, Volume 11, Issue 5, Pages 635-642 (2018)
doi: https://doi.org/10.3832/ifor2645-011
Published: Oct 04, 2018 - Copyright © 2018 SISEF

Research Articles

Although reforestation is frequently utilized in many Mediterranean Basin countries to restore burned Mediterranean pine woodlands, post-fire recovery of the plant community is often neglected. To compare the post-fire recovery of the plant community following active and indirect post-fire restoration techniques, we studied three post-fire regeneration treatments in a salvage-logged Pinus brutia forest, including two active (plantation and seeding) restoration techniques and one indirect (natural regeneration). An unburned pine stand was also included in the study. We applied the point-intercept method to obtain data on the presence and cover of individual species and functional groups in six replicate one-hectare plots for each treatment. We found no significant differences in plant species richness among post-fire treatments; however, plant community composition and vegetation structure were significantly different between treatments. There was a shift in plant community structure when active restoration techniques were applied, from the woody- and resprouter-dominated plant community of the unburned site to an annual herbaceous- and non-resprouter-dominated one. Our results suggest that active restoration by planting tree saplings in Mediterranean pine forests after a fire may decrease the plant community’s resilience and provide empirical evidence that pine plantation treatments change the plant species composition of these forests. These results have important implications for post-fire management of Mediterranean Basin pine forests.

Fire, Mediterranean Pine Forest, Plant Cover, Plant Functional Groups, Post-fire Restoration, Resilience, Species Diversity, Turkish Red Pine

  Introduction 

Pine forests cover large areas throughout the Mediterranean Basin and are of great ecological and economic importance ([51], [5]). Turkish red pine (Pinus brutia Ten.) and Aleppo pine (P. halepensis Mill.) form pine forests with the most prominent crown fire regimes in low altitudes in the Mediterranean Basin ([27]). In recent decades, especially in the western Mediterranean Basin, socio-economic changes (e.g., the rural-urban migration) and reforestation policies have resulted in homogenous pine stands that are sensitive to drought-driven large wildfires ([45], [46]).

Most of the low-altitude Mediterranean pine forests are resilient to fires and successful post-fire regeneration of these forests has been reported by several authors ([59], [50], [45]). However, the failure of post-fire establishment of pine seedlings in these forests has also been recorded, for instance on steep slopes or in poor soils ([59]), and especially if fires are very frequent ([15]). Field observations ([4], [58]) and modeling studies ([41]) suggest that if fires occur more frequently than 20 years, which is the time period needed for pine trees to develop a canopy seed bank (i.e., immaturity risk), then pine forests transform into open shrublands or grasslands.

In low-altitude Mediterranean pine forests, many species of angiosperms have acquired several adaptations to cope with fire ([40]), including resprouting from underground lignotubers and stimulation of germination by heat shock or smoke ([26]). Owing to these adaptations, post-fire plant diversity increases in the years following a fire until canopy closure is achieved ([27]) while post-fire successional process also contributes to the gamma diversity of the region as each seral stage has its own specific plant and animal species composition ([54], [22]). Many studies have documented a peak in plant diversity during the early stages of post-fire succession in fire-prone Mediterranean Basin habitats ([60], [23], [21]).

Post-fire regeneration of Mediterranean pine forests is a major economic concern in many countries within the Mediterranean Basin ([5], [42]). Therefore, national forest services frequently conduct active restoration by applying different techniques (e.g., pine plantation) for sustainable forestry in these pine forests ([63]). Owing to restoration priorities that favor pine plantations, many studies on post-fire regeneration in Mediterranean pine woodlands have also been performed, with a prominent focus on post-fire pine regeneration ([52], [62]). Few studies, however, have addressed the dynamics of plant community structure in burned Mediterranean Basin pine forests ([23], [21]). Contrary to the prevailing approach of post-fire management, natural regeneration and seeding methods have been suggested instead of pine plantation to restore burned areas in the Mediterranean Basin successfully and cost effectively ([5], [29], [34], [63]). It has also been suggested that less intensive post-fire management techniques would improve plant diversity in Mediterranean Basin forests ([30]), as has been concluded for fire-prone forests in the western United States ([37]). Moreover, owing to global change, post-fire restoration in Mediterranean forests requires a comprehensive approach ([12]). In short, “the restoration of a burned area is not just a matter of how to carry out reforestations” ([34]).

Turkey is one of the leading Mediterranean Basin countries in reforestation (mostly Pinus brutia - [45]); however, P. brutia stands are also utilized intensively for timber production ([33]). Various post-fire management techniques are applied to burned P. brutia forests in Turkey ([5]) without any consideration as to how different restoration techniques affect plant community structure and plant diversity, and with a prominent focus on pine regeneration for future wood production (Ç. Tavsanoglu, personal observation). In Turkey, salvage logging is the first application before any post-fire regeneration treatment in burned P. brutia forests due to economic concerns ([1]).

The present study aims to assess the response of the plant community to various post-fire regeneration treatments in salvage-logged Pinus brutia forests. We hypothesize that plant diversity differs substantially between active (i.e., planting and seeding) and indirect (i.e., natural regeneration) restoration techniques. We therefore expect more diverse and fire-resilient plant communities in areas subjected to indirect restoration.

  Materials and methods 

Study area

The study was conducted in Çetibeli district, Marmaris region, south-western Turkey (36.98° N, 28.32° E). The study area is dominated by native Turkish red pine (Pinus brutia) forests, with maquis shrubs (such as Quercus infectoria, Phillyrea latifolia, and Myrtus communis) also found in the understory with high coverage ([56]). The Marmaris region is one of the most frequently burned areas in south-western Turkey, with many burned sites co-occurring with unburned forests in the landscape. Consequently, both monopyric (i.e., annuals and post-fire seeders) and polypyric (i.e., post-fire resprouters) species exist in the region as in many typical crown-fire ecosystems ([47]), while the area’s vegetation consists of plant communities adapted to crown fire regimes ([54]). Stunning examples of monopyric species in southwestern Turkey include Chaenorhinum rubrifolium, whose germination is stimulated by multiple fire-related cues ([57]), many woody Lamiaceae species that has smoke-stimulated germination ([8]), several Cistus species in which germination is stimulated by various heat-shocks, and Pinus brutia, a serotinous pine tree ([56]). Many large resprouter shrubs, such as Phillyrea latifolia and Arbutus andrachne, are good examples of the region’s polypyric species ([56]). The climate is typically Mediterranean, with a prominent summer drought period, and wet winters. Serpentine soils cover most of the study area because of ophiolite rocks formed by underwater volcanic activity in the early Mesozoic. The study area is located between 70 and 400 m above sea level.

Fire and regeneration treatments

In the summer of 2002, a high-intensity, stand-replacing crown fire burned 1775 ha of Pinus brutia forest in the study region. After this fire event, fire-killed trees were salvage-logged within the first few months before several regeneration treatments (hereafter “treatment”) were applied to the burned area within the first year after the fire by the local forest service (see below). Although the extent of the burned area was sizeable, treatments were applied at a fine scale (in 1-5 ha sites) throughout the burned area.

The treatments applied to the burned area can be classified as active or indirect restoration techniques ([63]), which are both frequently applied in the regeneration of salvage-logged Pinus brutia forests by forest services ([5]). The first active restoration technique was the pine plantation (hereafter “plantation”) treatment, in which the vegetation remaining after salvage logging was removed by plowing before planting P. brutia saplings. The second active restoration technique was the “seeding” treatment, in which, after salvage logging, the cone-bearing branches of the burned trees and the remaining parts of the shrubs were homogeneously placed on the soil surface before additional Pinus brutia seeds from seed orchards from a neighboring forest locality were spread by hand over the site. The indirect restoration technique was “natural regeneration”, which meant leaving the site as found without applying any treatment after salvage logging.

Study sites and sampling design

We selected the three treatments described above (planting, seeding, and natural regeneration) within the area burned in 2002 and an unburned site next to the burned area. The unburned site had the same characteristics as the burned site in terms of the type of the geological material and soil structure while the pre-fire plant community of the burned site was similar to the unburned site ([55], [56]). Each treatment and unburned site included six 1-ha replicate plots for a total of 24 plots, evenly distributed over three aspects (north, south, and flat; see Tab. S1 and Fig. S1 in Supplementary material). We applied point-intercept methodology to obtain data on the presence and cover of individual species in the selected plots. At a location close to the center of each plot, two line transects, 50 m in length, were established. The distance between two transects in each plot was 20 m. We sampled 100 consecutive points at 50 cm intervals along each transect line, and recorded the plant taxa present at each point to estimate the cover of each species in each transect. This methodology allowed us to estimate mean cover values at the individual taxon level in each plot by averaging the values of the two transects. We also obtained mean cover values for functional groups by summing the cover values of the taxa included in the same functional group. Field sampling was conducted between August 2007 and February 2008. Where possible, plant individuals found at the sampling points were identified to the species level in the field and, if not possible, a specimen was taken for identification at the herbarium. Nomenclature followed Davis ([9]), Güner et al. ([18]), and Stevens ([53]) for the current family names.

Functional groups

We applied regeneration mode and growth form as functional grouping systems to better understand the effects of post-fire treatments on the plant community and vegetation structure at the functional group level. These functional grouping systems are fundamental ones for the fire-prone Mediterranean Basin ecosystems ([56]). Regeneration mode grouping was based on the regeneration traits of plants in crown fire ecosystems ([43]) and included the following groups: (i) obligate resprouters; (ii) facultative resprouters; (iii) obligate seeders; and (iv) species with no specific post-fire regeneration traits (hereafter “none”). Obligate resprouters regenerate only from under- or above-ground buds by resprouting after fire (R+P- in [43]); obligate seeders regenerate only from seeds, have fire-stimulated germination, and lack any resprouting ability (R-P+); and facultative resprouters can regenerate both by resprouting and seeding after fire (R+P+). The none group consisted of non-resprouter species lacking any evidence of post-fire germination stimulation (R-P-). We also considered obligate seeders with a soil seed bank as a separate functional group to distinguish their effects from Pinus brutia, which has a canopy seed bank. The regeneration modes of individual taxa were based on Paula et al. ([40]), Tavsanoglu & Gürkan ([56]), and field observations.

We also applied a binary growth form grouping to distinguish woody and herbaceous species, and these groups were further divided into additional sub-groups (tree, large shrub, shrub, scrub, liana, perennial forb, perennial graminoid, geophyte, annual forb, and annual graminoid) to describe how different growth forms are affected by each treatment. We also analyzed the responses of species belonging to different families to determine if there were any associations between treatments and species taxonomic status.

Data analysis

To obtain the overall cover of the functional group in each plot, we summed the cover of all species in each functional group. Mean cover values of functional groups for each treatment site and the unburned site were obtained by averaging plot values. Therefore, the cover of any functional group could exceed 100%. We also summed the number of species for each functional group. We utilized chi-square analysis to test the statistical significance of the associations between treatments and number of taxa in different functional groups.

Differences in the cover of each taxon and functional group across treatment groups (including the unburned site) were analyzed by one-way analysis of variance (ANOVA). Tukey’s HSD post-hoc test was applied to analyze the differences between treatments. Two-way ANOVAs were also conducted to test the effects of treatments and aspect on the cover of functional groups. For each functional group, we performed two separate two-way ANOVAs: one included the unburned site and all three post-fire treatments (planting, seeding, and natural regeneration); the other excluded the unburned site. The latter analysis was conducted to reduce the possibility of obtaining overestimated p-values indicating the presence of significant differences among groups, especially considering that the majority of variance in the data came from the unburned site. This enabled us to show more clearly the differences in the cover of functional groups across treatments (without the noise from the unburned site). Cover data were log-transformed before each analysis for a better approximation to the normal distribution.

Permutational multivariate analysis of variance was used to test whether the species composition of the plant community differed across treatments, based on 999 permutations of a Bray-Curtis dissimilarity matrix of the presence/absence of species in study plots. Non-metric multidimensional scaling (NMDS) was also performed to visualize the differences in species composition across treatments. We performed both analyses twice to determine the effects of the unburned site on the overall results: one included the unburned site and all three post-fire treatments (planting, seeding, and natural regeneration); the other excluded the unburned site. For these two analyses, we used “adonis” and “metaMDS” functions in the “vegan” package, respectively ([38]).

All analyses were performed using R statistical software (version 3.4.2, R Foundation for Statistical Computing, Vienna, Austria - ⇒ http:/­/­www.­R-project.­org/­).

  Results 

A total of 60 taxa were recorded in the study area (listed in Tab. S2, Supplementary material), belonging to 24 families and 51 genera; however, the study area was dominated by members of the Poaceae, Lamiaceae, and Fabaceae families. Many of the woody taxa were obligate resprouters whereas many of the herbaceous taxa were non-resprouters (Tab. 1). However, there was no relationship between the number of taxa within functional groups (regeneration mode and growth form) and treatments (Tab. 2).

Tab. 1 - Number of species according to their regeneration mode, growth form, and family in each treatment group. (Natural Reg): natural regeneration.

Group Subgroup Unburned Restoration technique
Plantation Seeding Natural Reg
All Species Total 28 35 40 32
Obligate resprouters 15 12 11 9
Facultative resprouters 5 6 7 4
Obligate seeders 4 8 10 9
None 4 9 12 10
Resprouters Total 20 18 18 13
Woody 17 11 14 10
Herbaceous 3 7 4 3
Non-resprouters Total 8 17 22 19
Woody 3 5 5 5
Herbaceous 5 12 17 14
Woody species Total 20 16 19 15
Trees 2 1 2 1
Large shrubs 9 3 6 4
Shrubs 3 5 5 4
Scrubs 5 6 5 5
Liana 1 1 1 1
Herbaceous Species Total 8 19 14 17
Perennials 3 8 6 6
- Perennial forbs 2 2 4 4
- Perennial graminoids 0 5 2 2
- Geophytes 1 1 0 0
Annuals 5 11 15 11
- Annual forbs 2 6 7 6
- Annual graminoids 3 5 8 5
Family Lamiaceae 4 3 3 4
Fabaceae 1 5 5 3
Asteraceae 1 3 3 4
Cistaceae 1 2 2 2
Poaceae 3 9 10 7

  Enlarge/Reduce  Open in Viewer

Tab. 2 - Association between treatments and number of taxa in different regeneration modes and different growth forms. The raw data is presented in Tab. 1. (df): degrees of freedom; (RM): regeneration mode; (GF): growth form.

Group χ2 df Prob.
RM (all) 2.0 6 0.916
RM (resprouting/non-resprouting) 6.6 3 0.086
RM × GF (woody/herbaceous) 3.1 6 0.790
GF (all) 17.7 24 0.817
GF (woody/herbaceous) 4.8 3 0.190

  Enlarge/Reduce  Open in Viewer

There were significant differences between the unburned site and treatment sites in the cover of one-third of the studied taxa (Tab. S3 in Supplementary material). Most differences were related to the regeneration mode of the taxa. That is, cover of seeder taxa, such as Cistus spp. and Cytisopsis pseudocytisus ssp. reeseana, were significantly higher in the seeding and natural regeneration treatments than in the unburned site. Cover of dominant resprouters either decreased (Quercus infectoria, Myrtus communis, and Styrax officinalis) or remained unchanged (Phillyrea latifolia) in burned sites compared to the unburned site. Significant increases in the cover of taxa in the none group were observed in the plantation treatment (e.g., Bupleurum orientale, Avena fatua, and Bromus spp. - see Tab. S3 in Supplementary material).

The results of the two-way ANOVAs showed that the unburned site was clearly different from the burned sites regarding the cover of functional groups (Tab. 3). By excluding the unburned site, less significant results were obtained in almost all functional groups, although the effects of the treatments were still significant for some functional groups. This analysis also showed that different post-fire treatments resulted in different cover values only for resprouters, woody species, and trees (Tab. 3). Aspect made a relatively limited contribution to the total variance and had a significant effect only on the cover of trees and liana (Tab. 3).

Tab. 3 - Results of two-way analysis of variance for the effects of treatment and aspect on the cover of regeneration modes, growth forms, and plant families. Two separate analysis were performed: including and excluding unburned site. (T × A): interaction of treatment and aspect; (ns): non-significant; (*): p < 0.05; (**): p < 0.01; (***): p < 0.001.

Groups With unburned site Excluding unburned site
Treatment Aspect T × A Treatment Aspect T × A
Total **** * ns ns ns ns
Obligate resprouters *** ns ns * ns ns
Facultative resprouters ns ns ns * ns ns
Obligate seeders *** ns ns ns ns ns
Obligate seeders (soil seed bank) ** ns ns ns ns ns
None * ns ns ns ns ns
Woody species **** ns ns *** ns ns
Trees **** ** ** ** ** *
Large shrubs **** ns * * ns ns
Shrubs *** ns ns * ns ns
Scrubs * * ns ns ns ns
Liana * ** * ns ** ns
Herbaceous species * ns ns * ns ns
Perennials ** ns ns ns ns ns
- Perennial forbs ns ns ns ns ns ns
- Perennial graminoids *** ns ns * ns ns
- Geophytes ns ns ns ns ns ns
Annuals ns ns ns ns ns ns
- Annual forbs * ns ns * ns ns
- Annual graminoids ns ns ns ns ns ns
Lamiaceae ns * ns ns ns ns
Fabaceae **** ns ns ns ns ns
Asteraceae ns ns ns ns ns ns
Cistaceae **** ns ns ** ns ns
Poaceae ** * ns * ns ns

  Enlarge/Reduce  Open in Viewer

More detailed analysis of the cover of functional groups in different treatments indicated that there were significant increases or decreases in different treatment groups compared to the unburned site (Tab. 4). Considering the woody species, the total cover of trees (mainly Pinus brutia) was dramatically reduced in the burned sites compared to the unburned site (from 88% down to 1%) while that of shrubs and scrubs increased (from 13% up to 50% and from 2% up to 19%, respectively). Total cover of herbaceous species significantly increased only in the plantation treatment compared to the unburnt site (from 9% to 56%) whereas no significant changes were found in either the seeding or natural regeneration treatments (Tab. 4). Increase in the cover of annuals was responsible for the significant change in total herbaceous cover in the plantation treatment; however, the lack of any increase in the cover of annuals resulted in an insignificant increase in the seeding and natural regeneration treatments. Specifically, the cover of perennial graminoids was significantly higher in the natural regeneration treatment than in the unburnt site (18% and 0%, respectively). The cover of Cistaceae, Poaceae, and Fabaceae families was significantly higher in the burned sites than in the unburned site whereas no significant change was observed in the cover of Lamiaceae and Asteraceae families.

Tab. 4 - Mean (± standard error) cover values for each functional group in different treatment sites. The results from the one-way analysis of variance for the effects of treatments on the cover of regeneration modes, growth forms, and plant families are shown. The same letter on the cover values indicates no significant difference (p > 0.05) across treatments. (Natural Reg): natural regeneration.

Groups Unburned Restoration technique F p
Plantation Seeding Natural Reg
Total 185.5 ± 14.0 a 98.7 ± 9.1 b 100.0 ± 5.8 b 107.7 ± 6.6 b 18.0 <0.0001
Obligate resprouters 74.9 ± 16.1 a 12.8 ± 3.1 b 18.6 ± 7.5 b 40.1 ± 6.3 ac 9.3 0.0005
Facultative resprouters 12.0 ± 7.8 5.4 ± 2.4 13.7 ± 1.2 9.6 ± 2.0 2.0 0.141
Obligate seeders 93.7 ± 2.4 a 39.8 ± 3.9 b 59.8 ± 7.5 c 52.9 ± 5.6 bc 14.3 <0.0001
Obligate seeders (soil seed bank) 5.5 ± 2.9 a 31.8 ± 4.5 b 57.2 ± 7.0 c 51.5 ± 5.5 bc 20.2 <0.0001
None 4.9 ± 2.4 a 40.7 ± 11.2 b 7.9 ± 2.6 ab 5.1 ± 2.4 ab 3.7 0.029
Woody species 114.7 ± 6.1 a 37.2 ± 6.8 b 75.2 ± 7.2 c 64.5 ± 4.8 c 22.4 <0.0001
Trees 88.5 ± 2.3 a 8.0 ± 2.6 b 2.7 ± 0.9 b 1.4 ± 0.4 b 20.7 <0.0001
Large shrubs 62.2 ± 10.3 a 5.7 ± 2.0 b 11.2 ± 5.5 b 16.5 ± 4.0 b 12.8 <0.0001
Shrubs 12.8 ± 7.7 a 23.0 ± 3.2 b 50.4 ± 3.4 b 44.8 ± 8.0 b 11.6 0.0001
Scrubs 2.3 ± 1.0 5.7 ± 3.4 18.7 ± 7.7 15.6 ± 8.1 2.3 0.109
Liana 11.1 ± 5.0 0.5 ± 0.3 3.5 ± 2.8 2.7 ± 2.2 2.0 0.140
Herbaceous species 8.7 ± 3.3 a 55.8 ± 12.4 b 13.7 ± 6.4 a 26.7 ± 3.8 ab 8.1 0.001
Perennials 0.7 ± 0.5 a 6.5 ± 2.6 bc 4.8 ± 3.0 ac 18.8 ± 2.7 b 10.1 0.0003
- Perennial forbs 0.6 ± 0.5 0.2 ± 0.1 1.2 ± 0.4 1.2 ± 0.7 1.4 0.279
- Perennial graminoids 0 a 5.9 ± 2.8 bc 3.6 ± 2.8 ab 17.7 ± 3.0 c 14.0 <0.0001
- Geophytes 0.1 ± 0.1 0.1 ± 0.1 0 0 0.7 0.582
Annuals 8.0 ± 3.5 49.3 ± 12.4 8.9 ± 3.7 7.8 ± 3.8 2.4 0.093
- Annual forbs 3.5 ± 2.3 ab 12.8 ± 3.5 b 1.8 ± 1.4 a 2.4 ± 1.6 ab 3.4 0.038
- Annual graminoids 4.5 ± 2.3 36.5 ± 10.5 7.0 ± 2.4 5.4 ± 2.5 3.0 0.057
Lamiaceae 4.5 ± 2.8 1.7 ± 0.8 1.1 ± 0.5 0.6 ± 0.3 0.7 0.584
Fabaceae 0.2 ± 0.2 a 13.8 ± 4.6 b 23.9 ± 5.5 b 21.8 ± 6.2 b 57.4 <0.0001
Asteraceae 0.1 ± 0.1 1.5 ± 1.1 0.8 ± 0.4 1.0 ± 0.5 1.6 0.219
Cistaceae 2.3 ± 0.6 a 18.0 ± 1.0 b 39.1 ± 3.9 c 35.9 ± 6.3 bc 51.4 <0.0001
Poaceae 4.5 ± 2.3 a 41.3 ± 10.2 b 10.6 ± 4.9 ab 23.1 ± 2.6 b 7.8 0.001

  Enlarge/Reduce  Open in Viewer

NMDS of species presence data differentiated the unburned site from burned sites (i.e., treatment groups - Fig. 1a), as was confirmed by the permutational multivariate analysis of variance (F = 5.6, R2 = 0.46, p = 0.001). Moreover, after excluding the unburned site, the cross-treatment differences were still significant (F = 3.4, R2 = 0.31, p = 0.003) and NMDS analysis revealed three separate groups (Fig. 1b). However, a clear difference in the two-dimensional space of the NMDS graph appeared between indirect (i.e., natural regeneration) and active (i.e., seeding and planting) restoration treatments after excluding the unburned site from the analysis (Fig. 1b). These results indicate a change in community composition in the burned sites compared to the unburned site. Moreover, they show that the natural regeneration treatment sites had different plant species compositions to the plantation and seeding treatment sites.

Fig. 1 - NMDS ordination graph of species presence across treatments. Two graphs are given: including (a) and excluding (b) the unburned site (UN) from the analysis (see Materials and methods section for details). Each point represents the species composition of the plant community in a single 1-ha plot. Confidence ellipses are also shown for each treatment. (NR): natural regeneration; (Seed): seeding; (Plant): plantation.

  Enlarge/Shrink   Download   Full Width  Open in Viewer

  Discussion 

Our study showed that plant community composition and vegetation structure significantly changed in burned sites compared to the unburned site in Pinus brutia forests. Moreover, this change became more drastic in areas where the plantation treatment was applied. Considering the coverage of plant functional groups, seeding and natural regeneration treatments had less impact on the vegetation structure than the plantation treatment did in P. brutia forests after fire.

Short-term increases in the number of plant species in burned pine forests of the Mediterranean Basin is very common ([23], [21]), which results from fire adaptations observed in many plants ([40]). Management decisions in favor of recruiting pine plantations, however, may lead to the disruption in the natural recovery process in such forests ([31], [16]). On the contrary, it is reported that plowing has minor and temporary effects on plant species richness and vegetation cover; however, it negatively affects pine regeneration in Mediterranean pine woodlands ([19]). As the benefits of planting seedlings offset by its negative effect on the small mammal community in a pine woodland dominated by the non-serotinous species Pinus nigra, it has been suggested that a multi-criteria approach should be implemented before selecting post-fire management practices in such forests ([14]). In our study, although there were no significant differences in plant species richness across the post-fire treatments, plant community composition and vegetation structure for natural regeneration and the other two (seeding and plantation) restoration techniques differed significantly. Consequently, many of the plants found in the seeding and plantation areas were not found in the natural regeneration areas and vice versa. This result indicates that there was a shift in plant community structure when active restoration techniques were applied, specifically from the woody- and resprouter-dominated plant community of the unburned site to an annual herbaceous- and non-resprouter-dominated one. Consequently, we rejected our first hypothesis that plant diversity differs across treatments. However, our results supported the second hypothesis - that indirect restoration sites have a more fire-resilient community than active ones. This result also shows that such a shift in the plant community composition can be masked if only species diversity measures are considered ([35], [2]). The case mentioned above was more dramatic in the plantation treatment in which annual species had approximately 40% more cover than others. The active restoration treatments we included in our study also differed from each other in plant species composition and the cover of the seeder functional group in that both were lower in the plantation than the seeding treatment. This difference suggests that fire-adapted seeder species were eliminated in the plantation treatment and replaced by non-resprouter species without any adaptation to fire. On the other hand, tree (i.e., pine) cover in the plantation treatment was six- and three-times higher than in the natural regeneration and seeding treatments, respectively. This result indicates that plantation is a successful treatment to regenerate the target species Pinus brutia in burned pine woodlands in areas where wood production is the main ecosystem service ([39]). However, the negative effects of pine plantations on several ecosystem services, such as providing suitable animal habitat, preventing soil erosion, and maintaining biodiversity, have also been acknowledged ([31], [39]). Even if the only management goal is regenerating the dominant pine species of the plant community in some areas, biodiversity is still an important part of these ecosystems, which provides services like promoting forest resilience ([61]). In some cases, moreover, even salvage logging is not the best option for post-fire management and it could have long-term negative impacts on ecological and socio-economical services ([7]). Unfortunately, because our sampling design did not include plots of natural regeneration without salvage logging, we cannot evaluate the possible effects of salvage logging on the post-fire recovery of plant community. Therefore, future studies about post-fire management in P. brutia forests should include burned plots in which salvage logging is not applied for a better understanding of the effects of salvage logging on the plant community in such forests.

Resilience is high in resprouter-dominated vegetation in fire-prone Mediterranean Basin areas ([25], [11], [4], [45], [17]) since resprouters can recover quickly after fire. Post-fire resilience in pine-dominated plant communities is also dependent on fire-persistent understory vegetation, including both resprouters ([11]) and seeders ([3]). Consequently, resilience to disturbance is a key functional element of Mediterranean plant communities ([25], [28]), and a deviation from the plant community composition that can be expected from an autosuccessional model (i.e., direct regeneration) is a potential indicator of low resilience in Mediterranean pine forests ([24]). The apparent change in plant community structure in our study, as indicated by significantly lower cover values of resprouters and seeders in plantation sites, therefore suggests that active restoration by planting Mediterranean pine forests after fire (i.e. ploughing and then replanting pine saplings) may decrease the resilience of the plant community compared to less artificial restoration tools (i.e., seeding and natural regeneration in our case). Furthermore, large shrubs had a significant place in the plant community in both the unburned and naturally-regenerated sites in our study, which suggests that these species are sensitive to active restoration techniques. As one of the providers of high forest resilience, this functional group could be used as a substitute for the tree component of the community for ecosystem services such as wood production (i.e., coppicing) and soil protection.

Successful pine regeneration can be achieved through indirect restoration techniques in burned Mediterranean pine forests ([52], [42], [62]). No effect of using log and branch barriers has been demonstrated in post-fire regeneration in Mediterranean pine forests ([49]) whereas the existence of branches on the forest floor is reported to have positive effects ([13], [44], [7]). In this respect, our results support the suggestion that indirect (i.e., natural regeneration) and relatively less artificial (i.e., seeding) restoration techniques should be applied instead of plantation in many cases while restoring burned fire-prone Mediterranean pine forests ([36], [48], [5], [31], [10], [63], [32], [30]). The functional group approach we used in our study provided practical knowledge to improve resilience in Mediterranean pine forest ecosystems and may help to predict the outcomes of future changes in fire regimes to which the plant community is adapted.

  Conclusions 

Our results provide empirical evidence that plantations are the least beneficial treatment for resilience in Mediterranean pine forests ([31], [20]). We therefore recommend that seeding and natural regeneration techniques should be preferred in salvage-logged Pinus brutia forests after fire. On the other hand, other restoration options that we did not test in our study may also help to improve the diversity and resilience of post-fire plant community, such as the plantation of resprouter species ([17]) and pine planting without removing regenerating vegetation. Our findings on the plant community shift also indicate that plant functional groups provide an effective tool for evaluating the effects of post-fire management approaches in fire-prone ecosystems ([6]). The results of our study have important implications for post-fire management of Mediterranean Basin pine forests.

  Acknowledgements 

We thank Yasin Ilemin and Kaan Ürker for their assistance in the field, and Baris Özüdogru, Evren Cabi, and Sinasi Yildirimli for their help during plant identification. We also thank three anonymous referees who made comments that significantly improved the manuscript. The plant specimens were identified in the Hacettepe University Herbarium. The data was obtained from field studies conducted as part of the Master’s of Science thesis work of Okan Ürker submitted to Hacettepe University. The present study was financially supported by the State Planning Organization of Turkey (DPT, project no: 2007K120920). The authors declare that they do not have any conflict of interest regarding this paper.

  References

(1)
Akay AE, Erdas O, Kanat M, Tutus A (2007). Post-fire salvage logging for fire-killed Brutian pine (Pinus brutia) trees. Journal of Applied Sciences 7: 402-406.
CrossRef | Gscholar
(2)
Alfaro-Sánchez R, Sánchez-Salguero R, De las Heras J, Hernánde-Tecles E, Moya D, López-Serrano FR (2015). Vegetation dynamics of managed Mediterranean forests 16 yr after large fires in southeastern Spain. Applied Vegetation Science 18: 272-282.
CrossRef | Gscholar
(3)
Arnan X, Rodrigo A, Retana J, Collins B (2007). Post-fire regeneration of Mediterranean plant communities at a regional scale is dependent on vegetation type and dryness. Journal of Vegetation Science 18: 111-122.
CrossRef | Gscholar
(4)
Baeza J, Valdecantos A, Alloza JA, Vallejo R (2007). Human disturbance and environmental factors as drivers of long-term post-fire regeneration patterns in Mediterranean forests. Journal of Vegetation Science 18: 243-252.
CrossRef | Gscholar
(5)
Boydak M (2004). Silvicultural characteristics and natural regeneration of Pinus brutia Ten. A review. Plant Ecology 171: 153-163.
CrossRef | Gscholar
(6)
Bradstock RA, Kenny BJ (2003). An application of plant functional types to fire management in a conservation reserve in southeastern Australia. Journal of Vegetation Science 13: 345-354.
CrossRef | Gscholar
(7)
Castro J, Allen CD, Molina-Morales M, Marañón-Jiménez S, Sánchez-Miranda A, Zamora R (2011). Salvage logging versus the use of burnt wood as a nurse object to promote post-fire tree seedling establishment. Restoration Ecology 19: 537-544.
CrossRef | Gscholar
(8)
Catav SS, Küçükakyüz K, Akbas K, Tavsanoglu C (2014). Smoke-enhanced seed germination in Mediterranean Lamiaceae. Seed Science Research 24: 257-264.
CrossRef | Gscholar
(9)
Davis PH (1985). Flora of Turkey and the East Aegean islands. Edinburgh University Press, Edinburgh, UK, vols. 1-9.
Gscholar
(10)
De las Heras J, Moya D, Vega JA, Daskalakou E, Vallejo VR, Grigoriadis N, Tsitsoni T, Baeza J, Valdecantos A, Fernández C, Espelta J, Fernandes P (2012). Post-fire management of serotinous pine forests. In: “Post-Fire Management and Restoration of Southern European Forests” (Moreira F, Arianoutsou M, Corona P, De las Heras J eds). Managing Forest Ecosystems, vol. 24, Springer, Dordrecht, Netherlands, pp. 121-150.
CrossRef | Gscholar
(11)
Díaz-Delgado R, Lloret F, Pons X, Terradas J (2002). Satellite evidence of decreasing resilience in Mediterranean plant communities after recurrent wildfires. Ecology 83: 2293-2303.
CrossRef | Gscholar
(12)
Doblas-Miranda E, Martínez-Vilalta J, Lloret F, Alvarez A, Avila A, Bonet FJ, Brotons L, Castro J, Curiel Yuste J, Díaz M, Ferrandis P, García-Hurdato E, Iriondo JM, Keenan TF, Latron J, Llusià J, Loepfe L, Mayol M, Moré G, Moya D, Peñuelas J, Pons X, Poyatos R, Sardans J, Sus O, Vallejo VR, Vayreda J, Retana J (2015). Reassessing global change research priorities in Mediterranean terrestrial ecosystems: how far have we come and where do we go from here? Global Ecology and Biogeography 24: 25-43.
CrossRef | Gscholar
(13)
Eron Z, Sarigül M (1992). Natural regeneration of Pinus brutia Ten. by laying-out of cone-bearing branches on fire-burned areas in Aegean region. Technical Report Series no. 48, Turkish Forest Research Institute, vol. 38, pp. 7-37. [in Turkish with English summary]
Gscholar
(14)
Espelta JM, Retana J, Habrouk A (2003). An economic and ecological multi-criteria evaluation of reforestation methods to recover burned Pinus nigra forests in NE Spain. Forest Ecology and Management 180: 185-198.
CrossRef | Gscholar
(15)
Eugenio M, Verkaik I, Lloret F, Espelta JM (2006). Recruitment and growth decline in Pinus halepensis populations after recurrent wildfires in Catalonia (NE Iberian Peninsula). Forest Ecology and Management 231: 47-54.
CrossRef | Gscholar
(16)
Gómez-Aparicio L, Zavala MA, Bonet FJ, Zamora R (2009). Are pine plantations valid tools for restoring Mediterranean forests? An assessment along abiotic and biotic gradients. Ecological Applications 19: 2124-2141.
CrossRef | Gscholar
(17)
Granados ME, Vilagrosa A, Chirino E, Vallejo VR (2016). Reforestation with resprouter species to increase diversity and resilience in Mediterranean pine forests. Forest Ecology and Management 362: 231-240.
CrossRef | Gscholar
(18)
Güner A, Aslan S, Ekim T, Vural M, Babaç MT (2012). Türkiye Bitkileri Listesi (Damarli Bitkiler) [The List of Plant of Turkey (Vascular Plants)]. Flora Arastirmalari Dernegi ve Nezahat Gökyigit Botanik Bahçesi Yayini, Istanbul, Turkey, pp. 1290. [in Turkish]
Gscholar
(19)
Hibsher N, Moshe Y, Bney-Moshe E, Ben-Moshe E, Zangi E, Zuck A, Osem Y (2013). Post-fire regeneration in Mediterranean reforested sites as affected by mechanical site preparation: lessons for restoration. Applied Vegetation Science 16: 629-639.
CrossRef | Gscholar
(20)
Jucker Riva M, Liniger H, Valdecantos A, Schwilch G (2016). Impacts of land management on the resilience of Mediterranean dry forests to fire. Sustainability 8 (10): 981.
CrossRef | Gscholar
(21)
Kavgaci A, Carni A, Basaran S, Basaran MA, Košir P, Marinšek A, Silc U (2010). Long-term post-fire succession of Pinus brutia forest in the east Mediterranean. International Journal of Wildland Fire 19: 599-605.
CrossRef | Gscholar
(22)
Kaynas BY (2017). Long-term changes in surface-active beetle communities in a post-fire successional gradient in Pinus brutia forests. iForest - Biogeosciences and Forestry 10 (2): 376-382.
CrossRef | Gscholar
(23)
Kazanis D, Arianoutsou M (2004a). Long-term post-fire vegetation dynamics in Pinus halepensis forests of Central Greece: a functional group approach. Plant Ecology 171: 101-121.
CrossRef | Gscholar
(24)
Kazanis D, Arianoutsou M (2004b). Factors determining low Mediterranean ecosystems resilience to fire: the case of Pinus halepensis forests. In: Proceedings of the “10th MEDECOS Conference” (Arianoutsou M, Papanastasis VP eds). Rhodes (Greece) 25 Apr - 1 May 2004. Millpress, Rotterdam, Netherlands, pp. 1-12.
Gscholar
(25)
Keeley JE (1986). Resilience of Mediterranean shrub communities to fires. In: “Resilience in mediterranean-type ecosystems” (Lieth H, Mooney HA, Dell B, Hopkins AJ, Lamont BB eds). Tasks for vegetation science, vol. 16, Springer, Dordrecht, Netherlands, pp. 95-112.
CrossRef | Gscholar
(26)
Keeley JE, Pausas JG, Rundel PW, Bond WJ, Bradstock RA (2011). Fire as an evolutionary pressure shaping plant traits. Trends in Plant Science 16: 406-411.
CrossRef | Gscholar
(27)
Keeley JE, Bond WJ, Bradstock RA, Pausas JG, Rundel PW (2012). Fire in Mediterranean ecosystems: ecology, evolution and management. Cambridge University Press, Cambridge, UK, pp. 515.
CrossRef | Gscholar
(28)
Lavorel S (1999). Ecological diversity and resilience of Mediterranean vegetation to disturbance. Diversity and Distributions 5: 3-13.
CrossRef | Gscholar
(29)
Leverkus AB, Puerta-Piñero C, Guzmán-Alvarez JR, Navarro J, Castro J (2012). Post-fire salvage logging increases restoration costs in a Mediterranean mountain ecosystem. New Forests 43: 601-613.
CrossRef | Gscholar
(30)
Leverkus AB, Lorite J, Navarro FB, Sánchez-Cañete EP, Castro J (2014). Post-fire salvage logging alters species composition and reduces cover, richness, and diversity in Mediterranean plant communities. Journal of Environmental Management 133: 323-331.
CrossRef | Gscholar
(31)
Maestre FT, Cortina J (2004). Are Pinus halepensis plantations useful as a restoration tool in semiarid Mediterranean areas? Forest Ecology and Management 198: 303-317.
CrossRef | Gscholar
(32)
Marañón-Jiménez S, Castro J, Querejeta JI, Fernández-Ondoño E, Allen CD (2013). Post-fire wood management alters water stress, growth, and performance of pine regeneration in a Mediterranean ecosystem. Forest Ecology and Management 308: 231-239.
CrossRef | Gscholar
(33)
Ministry of Environment and Forestry of Turkey (2010). Forestry statistics 2008. Publ. no. 384, Turkish Statistical Institute Printing Division, Ankara, Turkey, pp. 65.
Gscholar
(34)
Moreira F, Arianoutsou M, Vallejo VR, De las Heras J, Corona P, Xanthopoulos G, Fernandes P, Papageorgiou K (2012). Setting the scene for post-fire management. In: “Post-Fire Management and Restoration of Southern European Forests” (Moreira F, Arianoutsou M, Corona P, De las Heras J eds). Managing Forest Ecosystems, vol. 24, Springer, Dordrecht, Netherlands, pp. 1-19.
CrossRef | Gscholar
(35)
Moya D, De las Heras J, López-Serrano FR, Condes S, Alberdi I (2009). Structural patterns and biodiversity in burned and managed Aleppo pine stands. Plant Ecology 200: 217-228.
CrossRef | Gscholar
(36)
Neeman G (1997). Regeneration of natural pine forest - Review of work done after the 1989 fire in Mount Carmel, Israel. International Journal of Wildland Fire 7: 295-306.
CrossRef | Gscholar
(37)
Noss RF, Franklin JF, Baker WL, Schoennagel T, Moyle PB (2006). Managing fire-prone forests in the western United States. Frontiers in Ecology and the Environment 4: 481-487.
CrossRef | Gscholar
(38)
Oksanen J, Blanchet FG, Friendly M, Kindt R, Legendre P, McGlinn D, Minchin PR, Hara RB, Simpson GL, Solymos P, Stevens MHH, Szoecs E, Wagner H (2018). vegan: community ecology package. R package version 2.4-6.
Online | Gscholar
(39)
Ozkan UY, Ozdemir I (2016). Structural characteristics of planted and naturally regenerated brutian pine stands. Turkish Journal of Forestry 17: 118-124.
Gscholar
(40)
Paula S, Arianoutsou M, Kazanis D, Tavsanoglu C, Lloret F, Buhk C, Ojeda F, Luna B, Moreno JM, Rodrigo A, Espelta JM, Palacio S, Fernández-Santos B, Fernandes PM, Pausas JG (2009). Fire-related traits for plant species of the Mediterranean Basin. Ecology 90: 1420.
CrossRef | Gscholar
(41)
Pausas JG (1999). Response of plant functional types to changes in the fire regime in Mediterranean ecosystems. A simulation approach. Journal of Vegetation Science 10: 717-722.
CrossRef | Gscholar
(42)
Pausas JG, Bladé C, Valdecantos A, Seva JP, Fuentes D, Alloza JA, Vilagrosa A, Bautista S, Cortina J, Vallejo R (2004a). Pines and oaks in the restoration of Mediterranean landscapes in Spain: new perspectives for an old practice - a review. Plant Ecology 171: 209-220.
CrossRef | Gscholar
(43)
Pausas JG, Bradstock RA, Keith DA, Keeley JE, Fire Network GCTE (2004b). Plant functional traits in relation to fire in crown-fire ecosystems. Ecology 85: 1085-1100.
CrossRef | Gscholar
(44)
Pausas JG, Riberio E, Vallejo R (2004c). Post-fire regeneration variability of Pinus halepensis in the eastern Iberian Peninsula. Forest Ecology and Management 203: 251-259.
CrossRef | Gscholar
(45)
Pausas JG, Llovet J, Rodrigo A, Vallejo R (2008). Are wildfires a disaster in the Mediterranean basin? - A review. International Journal of Wildland Fire 17: 713-723.
CrossRef | Gscholar
(46)
Pausas JG, Fernández-Muñoz S (2012). Fire regime changes in the Western Mediterranean Basin: from fuel-limited to drought-driven fire regime. Climatic Change 110: 215-226.
CrossRef | Gscholar
(47)
Pausas JG, Keeley JE (2014). Evolutionary ecology of resprouting and seeding in fire-prone ecosystems. New Phytologist 204: 55-65.
CrossRef | Gscholar
(48)
Pérez B, Moreno JM (1998). Fire type and forestry management effects on the early postfire vegetation dynamics of a Pinus pinaster woodland. Plant Ecology 134: 27-41.
CrossRef | Gscholar
(49)
Raftoyannis Y, Spanos I (2005). Evaluation of log and branch barriers as post-fire rehabilitation treatments in a Mediterranean pine forest in Greece. International Journal of Wildland Fire 14: 183-188.
CrossRef | Gscholar
(50)
Rodrigo A, Retana J, Pico FX (2004). Direct regeneration is not the only response of Mediterranean forests to large fires. Ecology 85: 716-729.
CrossRef | Gscholar
(51)
Scarascia-Mugnozza G, Oswald H, Piussi P, Radoglou K (2000). Forests of the Mediterranean region: gaps in knowledge and research needs. Forest Ecology and Management 132: 97-109.
CrossRef | Gscholar
(52)
Spanos IA, Daskalakou EN, Thanos CA (2000). Postfire, natural regeneration of Pinus brutia forests in Thasos island, Greece. Acta Oecologica 21: 13-20.
CrossRef | Gscholar
(53)
Stevens PF (2001). Angiosperm phylogeny. Web site.
Online | Gscholar
(54)
Tavsanoglu C (2008). Post-fire vegetation dynamics of Pinus brutia (Turkish Red Pine) forests of Marmaris region. PhD thesis, Hacettepe University, Ankara, Turkey, pp. 106. [in Turkish with English abstract]
Gscholar
(55)
Tavsanoglu C, Gürkan B (2010). Physical and chemical properties of the soils at burned and unburned Pinus brutia Ten. forest sites in the Marmaris region, Turkey. Hacettepe Journal of Biology and Chemistry 38: 71-76.
Gscholar
(56)
Tavsanoglu C, Gürkan B (2014). Long-term post-fire dynamics of co-occurring woody species in Pinus brutia forests: the role of regeneration mode. Plant Ecology 215: 355-365.
CrossRef | Gscholar
(57)
Tavsanoglu C, Ergan G, Catav SS, Zare G, Küçükakyüz K, Ozüdogru B (2017). Multiple fire-related cues stimulate germination in Chaenorhinum rubrifolium (Plantaginaceae), a rare annual in the Mediterranean Basin. Seed Science Research 27: 26-38.
CrossRef | Gscholar
(58)
Tessler N, Wittenberg L, Provizor E, Greenbaum N (2014). The influence of short-interval recurrent forest fires on the abundance of Aleppo pine (Pinus halepensis Mill.) on Mount Carmel, Israel. Forest Ecology and Management 324: 109-116.
CrossRef | Gscholar
(59)
Thanos CA, Doussi MA (2000). Post-fire regeneration of Pinus brutia forests. In: “Ecology, Biogeography and Management of Pinus halepensis and P. brutia forest ecosystems in the Mediterranean basin” (Ne’eman G, Trabaud L eds). Backhuys Publishers, Leiden, Netherlands, pp. 291-301.
Gscholar
(60)
Trabaud L, Lepart J (1980). Diversity and stability in garrigue ecosystems after fire. Plant Ecology 43: 49-57.
CrossRef | Gscholar
(61)
Thompson I, Mackey B, McNulty S, Mosseler A (2009). Forest resilience, biodiversity, and climate change: a synthesis of the biodiversity/resilience/stability relationship in forest ecosystems. Technical Series no. 43, Secretariat of the Convention on Biological Diversity, Montreal, Canada, pp. 67.
Gscholar
(62)
Tsitsoni T, Ganatsas P, Zagas T, Tsakaldimi M (2004). Dynamics of postfire regeneration of Pinus brutia Ten. in an artificial forest ecosystem of northern Greece. Plant Ecology 171: 165-174.
CrossRef | Gscholar
(63)
Vallejo VR, Arianoutsou M, Moreira F (2012). Fire ecology and post-fire restoration approaches in Southern European forest types. In: “Post-Fire Management and Restoration of Southern European Forests” (Moreira F, Arianoutsou M, Corona P, De las Heras J eds). Managing Forest Ecosystems, vol. 24, Springer, Dordrecht, Netherlands, pp. 93-119.
CrossRef | Gscholar

Authors’ Affiliation

(1)
Okan Ürker
Çagatay Tavsanoglu
Fire Ecology and Seed Research Laboratory, Division of Ecology, Department of Biology, Hacettepe University, 06800 Beytepe, Ankara (Turkey)
(2)
Behzat Gürkan
Institute of Natural Sciences, Yasar University, Izmir (Turkey)

Corresponding author

 
Çagatay Tavsanoglu
ctavsan@hacettepe.edu.tr

Citation

Ürker O, Tavsanoglu Ç, Gürkan B (2018). Post-fire recovery of the plant community in Pinus brutia forests: active vs. indirect restoration techniques after salvage logging. iForest 11: 635-642. - doi: 10.3832/ifor2645-011

Academic Editor

Davide Ascoli

Paper history

Received: Oct 08, 2017
Accepted: Jul 04, 2018

First online: Oct 04, 2018
Publication Date: Oct 31, 2018
Publication Time: 3.07 months

© SISEF - The Italian Society of Silviculture and Forest Ecology 2018

  Open Access

This article is distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Creative Commons Licence

Breakdown by View Type

(Waiting for server response...)

Article Usage

Total Article Views: 5242
(from publication date up to now)

Breakdown by View Type
HTML Page Views: 3902
Abstract Page Views: 245
PDF Downloads: 943
Citation/Reference Downloads: 4
XML Downloads: 148

Web Metrics
Days since publication: 411
Overall contacts: 5242
Avg. contacts per week: 89.28

Article citations are based on data periodically collected from the Clarivate Web of Science web site
(last update: Aug 2019)

Total number of cites (since 2018): 1
Average cites per year: 0.50

 
 

Publication Metrics

by Dimensions ©

List of the papers citing this article based on CrossRef Cited-by.

 

iForest Similar Articles

 

This website uses cookies to ensure you get the best experience on our website