Forests

16 pages, 1031 KB

Open AccessArticle

Differences in Soil Solution Chemistry and Their Vertical Variation Between Moso Bamboo Forests and Japanese Cedar Plantations in Western Japan

by Dongchuan Fu and Masaaki Chiwa

Forests 2025, 16(10), 1519; https://doi.org/10.3390/f16101519 - 26 Sep 2025

Abstract

Bamboo invasion into adjacent forests highlights the need to clarify its ecological impacts, particularly on soil solution chemistry, which influences forest nutrient availability and downstream water quality. This study examined how bamboo invasion alters base cations and anion concentrations, their vertical distribution, and [...] Read more.

Bamboo invasion into adjacent forests highlights the need to clarify its ecological impacts, particularly on soil solution chemistry, which influences forest nutrient availability and downstream water quality. This study examined how bamboo invasion alters base cations and anion concentrations, their vertical distribution, and the distinct ionic compositions maintaining charge balance in soil solution by comparing Moso bamboo (BF) and adjacent Japanese cedar (CF) forests. In surface soil solution (5 cm), most ion concentrations were significantly higher in CF than in BF, likely attributable to a greater interception of atmospheric nitrogen resulting from taller tree height in CF. In vertical distribution, CF showed generally higher ion concentrations in surface soil solution than at 50 cm, whereas in BF, this phenomenon was observed only for NO₃⁻, NH₄⁺, and K⁺, consistent with bamboo’s high demand for macronutrients. Significant correlations between the concentration of NO₃⁻ and those of Ca²⁺ and Mg²⁺ were absent only in BF soil leachate. Conversely, a deficit of strong anions showed a significant correlation with the concentration of Ca²⁺ and Mg²⁺ in BF soil leachate, with HCO₃⁻ identified as a potentially major component. Our findings provide insights into the concomitant-ion relationships between base cations and NO₃⁻ across forest types and soil depths. Full article

(This article belongs to the Section Forest Soil)

22 pages, 8647 KB

Open AccessArticle

Ecosystem Health Assessment and Zoning at the County Scale: Evidence from Fujian, Southern China’s Key Forest Region

by Shuqi Yang, Jixing Huang, Wanyi Liu, Yiqun Zhuang, Jinhuang Lin and Yongwu Dai

Forests 2025, 16(10), 1518; https://doi.org/10.3390/f16101518 - 26 Sep 2025

Abstract

Investigating the spatiotemporal distribution patterns of regional ecosystem health and the methods for optimizing their zoning is essential for enhancing ecosystem management and sustainable development. This study takes Fujian Province, a pivotal forest region in southern China, as the research object to establish [...] Read more.

Investigating the spatiotemporal distribution patterns of regional ecosystem health and the methods for optimizing their zoning is essential for enhancing ecosystem management and sustainable development. This study takes Fujian Province, a pivotal forest region in southern China, as the research object to establish a county-level ecosystem health evaluation framework grounded in the vitality–organization–resilience–ecosystem (VORS) model. It further conducts a comprehensive spatial–temporal analysis of ecosystem health dynamics from 2000 to 2020 and explores ecological management zoning and optimization strategies. The results indicate that (1) from 2000 to 2020, the overall ecosystem health level in Fujian Province maintained a relatively high status and exhibited a steady upward trajectory, with the index rising from 0.4694 in 2000 to 0.4762 in 2010, and further increasing to 0.4865 in 2020. (2) The health of ecosystems in Fujian exhibits significant geographical autocorrelation and aggregation, characterized mostly by high–high and low–low clusters. Typically, it has a geographical distribution characterized by elevated values in the northwest and diminished values in the southeast. (3) In light of the present condition and temporal dynamics of ecosystem health, the study classifies Fujian’s counties into three ecological management categories—conservation, stabilization, and reshaping zones—and puts forward tailored optimization measures for each region. The methodology employed in this study provides a general framework for ecosystem health assessment, which can offer useful references and insights for forest ecosystem health evaluation and refined, zone-specific ecological management in forest regions. Full article

(This article belongs to the Section Forest Ecology and Management)

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21 pages, 3963 KB

Open AccessArticle

Estimating Mangrove Aboveground Biomass Using Sentinel-2 and ALOS-2 Imagery: A Case Study of the Matang Mangrove Reserve, Malaysia

by Han Zhou, Abdul Rashid Mohamed Shariff, Siti Khairunniza Bejo, Mahirah Jahari, Helmi Zulhaidi Bin Mohd Shafri, Hamdan Bin Omar, Laili Nordin, Bambang Trisasongko and Wataru Takeuchi

Forests 2025, 16(10), 1517; https://doi.org/10.3390/f16101517 - 26 Sep 2025

Abstract

Mangroves play a critical role in global carbon sequestration, biodiversity conservation, and climate change mitigation. Accurately quantifying mangrove biomass is essential for sustainable forest management and carbon accounting. Yet, the structural complexity and species diversity of mangrove ecosystems pose significant challenges for accurate [...] Read more.

Mangroves play a critical role in global carbon sequestration, biodiversity conservation, and climate change mitigation. Accurately quantifying mangrove biomass is essential for sustainable forest management and carbon accounting. Yet, the structural complexity and species diversity of mangrove ecosystems pose significant challenges for accurate estimation. In this study, we developed an integrated model that combines multispectral imagery and radar data. Using Sentinel-2 and ALOS-2 satellite imagery combined with field measurements, these data were used to construct linear regression and random forest models for the Matang Mangrove Reserve, Malaysia. We further analyzed the relationships between vegetation indices, radar polarization modes, and biomass. Results indicate that the average biomass is approximately 146 t/ha. The Optimized Soil-Adjusted Vegetation Index (OSAVI) and horizontal–vertical (HV) polarization showed the strongest correlation with field-measured biomass, with an R² of 0.735 and a root mean square error (RMSE) of 46.794 t/ha. This study provides a scientific basis and technical support for mangrove carbon stock assessment, ecosystem management, and climate change mitigation strategies, and highlights the potential of integrating optical and radar remote sensing for large-scale mangrove biomass monitoring. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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11 pages, 5563 KB

Open AccessArticle

Estimation of Litter Yield and Decomposition Rate in Dahurian Larch Forests of the Greater Khingan Mountains

by Zhiyong Cai, Long Sun, Jiabao Sun and Haiqing Hu

Forests 2025, 16(10), 1516; https://doi.org/10.3390/f16101516 - 25 Sep 2025

Abstract

The aim of this paper is to investigate forest litter yield and decomposition rate estimation methods to provide a basic theory for litter production and decomposition studies and a scientific foundation for forest management practices. The Greater Khingan Dahurian larch (Larix gmelinii [...] Read more.

The aim of this paper is to investigate forest litter yield and decomposition rate estimation methods to provide a basic theory for litter production and decomposition studies and a scientific foundation for forest management practices. The Greater Khingan Dahurian larch (Larix gmelinii) forest in China was taken as the study subject. Forest litter was defined as the cumulative product of annual litterfall. The Olson exponential decay model, which is widely recognized in ecological studies, was employed to develop a system of equations representing the dynamic equilibrium among litter production, decomposition, and accumulation. Litter yield and decomposition rate estimation models were formulated based on this system. Model parameters were analyzed using multiple linear regression techniques. The proposed estimation methods were verified through field survey data and one-sample t-tests. The relative error for litter production estimation ranged from 0.01 to 0.25, with an average of 0.13, and the t-test yielded a p-value of 0.108. The relative error of the decomposition rate estimation was 0.00–0.35, with an average of 0.12, and the corresponding t-test yielded a p-value of 0.151. A litter yield and decomposition rate model with easily obtained predictor variables was constructed in this study. The model can rapidly estimate the litter yield and decomposition rate of survey sites and has important application value for litter yield- and decomposition-related studies. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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23 pages, 5708 KB

Open AccessArticle

Exploring the Role of Urban Green Spaces in Regulating Thermal Environments: Comparative Insights from Seoul and Busan, South Korea

by Jun Xia, Yue Yan, Ziyuan Dou, Dongge Han and Ying Zhang

Forests 2025, 16(10), 1515; https://doi.org/10.3390/f16101515 - 25 Sep 2025

Abstract

Urban heat islands are intensifying under the dual pressures of global climate change and rapid urbanization, posing serious challenges to ecological sustainability and human well-being. Among the factors influencing urban thermal environments, vegetation and green spaces play a critical role in mitigating heat [...] Read more.

Urban heat islands are intensifying under the dual pressures of global climate change and rapid urbanization, posing serious challenges to ecological sustainability and human well-being. Among the factors influencing urban thermal environments, vegetation and green spaces play a critical role in mitigating heat accumulation through canopy cover, evapotranspiration, and ecological connectivity. In this study, a comparative analysis of Seoul and Busan—two representative metropolitan areas in South Korea—was conducted using land surface temperature (LST) data derived from Landsat 8 and a set of multi-source spatial indicators. The nonlinear effects and interactions among built environment, socio-economic, and ecological variables were quantified using the Extreme Gradient Boosting (XGBoost) model in conjunction with Shapley Additive Explanations (SHAP). Results demonstrate that vegetation, as indicated by the Normalized Difference Vegetation Index (NDVI), consistently exerts significant cooling effects, with a pronounced threshold effect observed when NDVI values exceed 0.6. Furthermore, synergistic interactions between NDVI and surface water availability, measured by the Normalized Difference Water Index (NDWI), substantially enhance ecological cooling capacity. In contrast, areas with high building and population densities, particularly those at lower elevations, are associated with increased LST. These findings underscore the essential role of green infrastructure in regulating urban thermal environments and provide empirical support for ecological conservation, urban greening strategies, and climate-resilient urban planning. Strengthening vegetation cover, enhancing ecological corridors, and integrating greening policies across spatial scales are vital for mitigating urban heat and improving climate resilience in rapidly urbanizing regions. Full article

(This article belongs to the Special Issue Microclimate Development in Urban Spaces)

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16 pages, 6817 KB

Open AccessArticle

Quantifying Non-Linearities and Interactions in Urban Forest Cooling Using Interpretable Machine Learning

by Yixuan Zong, Yiqi Yu, Kexin Peng, Rui Zhang and Wen Zhou

Forests 2025, 16(10), 1514; https://doi.org/10.3390/f16101514 - 25 Sep 2025

Abstract

The cooling effect of urban forests has been widely investigated to support climate-adaptive spatial planning. However, studies on the impacts of key landscape drivers have often produced conflicting results, limiting their practical applicability. These inconsistencies may stem from an oversimplified focus on the [...] Read more.

The cooling effect of urban forests has been widely investigated to support climate-adaptive spatial planning. However, studies on the impacts of key landscape drivers have often produced conflicting results, limiting their practical applicability. These inconsistencies may stem from an oversimplified focus on the global effects of individual factors, while neglecting non-linear threshold behaviors and pairwise interactions. To address this gap, this study employed an interpretable machine learning framework (XGBoost-SHAP) to quantify the seasonal non-linearities, thresholds, and interaction effects of landscape drivers on urban forest cooling in Suzhou, a subtropical Chinese city. The results indicate that the combined explanatory power of neighboring water body proportion (NWP), neighboring green space proportion (NGP), vegetation density (NDVI), spatial characteristics (Area, SHAPE), and elevation on the cooling intensity of urban forest patches was strongest in summer (R² = 0.615) and weakest in winter (R² = 0.316). Among these, NWP, NGP, and NDVI were the dominant drivers, while patch area and shape exhibited weaker marginal effects. NWP significantly enhances cooling only after exceeding seasonal critical thresholds (11%–15%). NGP contributed positively above ~40% in warm seasons but suppressed cooling above 37% in winter. Patch area exhibits a logarithmic relationship with cooling intensity, with a critical threshold of approximately 2.48 ha and saturation thresholds between 12 and 14 ha. SHAPE exerted positive effects in spring and winter, negative effects in summer, and a transition from negative to positive in autumn. Notably, significant, threshold-modulated interactions were identified, including those between NDVI and NWP, SHAPE and NDVI, SHAPE and NGP, NWP and NDVI, NWP and NGP, and NGP and NDVI. In each interaction, the first factor regulates and reverses the effect of the second once specific thresholds are exceeded. This study provides actionable, evidence-based guidance for the planning and optimized design of urban forests. Full article

(This article belongs to the Section Urban Forestry)

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16 pages, 3181 KB

Open AccessArticle

Linking Morphological Traits of Fine Root to Soil CO₂ Efflux in Middle-Aged Plantations of Four Tree Species

by Seung Won Lim, Kyu Hong Song, Ji Won Jang, Se Hee Lee, Namin Koo, Sukwoo Kim and Nam Jin Noh

Forests 2025, 16(10), 1513; https://doi.org/10.3390/f16101513 - 25 Sep 2025

Abstract

Understanding belowground carbon dynamics is essential for predicting the carbon balance of forest ecosystems. This study aimed to investigate links between soil CO₂ efflux (R_S), soil physicochemical properties, and fine-root morphology across four middle-aged plantations of different species (Robinia [...] Read more.

Understanding belowground carbon dynamics is essential for predicting the carbon balance of forest ecosystems. This study aimed to investigate links between soil CO₂ efflux (R_S), soil physicochemical properties, and fine-root morphology across four middle-aged plantations of different species (Robinia pseudoacacia, Quercus mongolica, Pinus koraiensis, and Metasequoia glyptostroboides) in Mt. Ansan, Seoul, Republic of Korea. Seasonal measurements of R_S, soil temperature (T_S), and soil water content (SWC) were conducted, and soils and fine roots (≤2.0 mm) were analyzed for physicochemical properties and morphological traits, with a focus on very-fine roots (≤0.5 mm). The results showed that R_S was positively correlated with T_S (r = 0.77) and negatively with SWC (r = −0.33). R_S normalized at 25 °C (R₂₅), differed significantly among plantations, and exhibited strong positive correlations with electrical conductivity (r = 0.81), as well as with total nitrogen and carbon concentrations and clay content. Among fine root traits, the length, surface area, and volume of very-fine roots exhibited the strongest associations with R₂₅, underscoring their pivotal role in regulating belowground respiration. These findings suggest that species-specific fine root strategies and soil conditions jointly control R_S dynamics, particularly under warmer conditions, and highlight very-fine root traits as key indicators of soil carbon flux in forest ecosystems. Full article

(This article belongs to the Special Issue Belowground Carbon Flux in Forests: Carbon Emission, Storage and Beyond)

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15 pages, 6592 KB

Open AccessArticle

Longleaf Pine Growth Divergence Increases over Time Across Its Geographic Range

by Xiongwen Chen, John L. Willis and David C. Clabo

Forests 2025, 16(10), 1512; https://doi.org/10.3390/f16101512 - 25 Sep 2025

Abstract

The “divergence problem” in recent decades is a tendency for trees in high latitudes to lose climate sensitivity. Growth divergence has been reported for certain tree species in alpine or northern latitude locations but has yet to be found in species with southern [...] Read more.

The “divergence problem” in recent decades is a tendency for trees in high latitudes to lose climate sensitivity. Growth divergence has been reported for certain tree species in alpine or northern latitude locations but has yet to be found in species with southern distributions. This retrospective study used tree ring data collected from longleaf pine trees (Pinus palustris Mill.) in natural stands and a young plantation to test whether divergence exists in this important southeastern tree species. Our results demonstrate that a growth divergence in basal area increment (BAI) occurred among individual longleaf pines within stands. The BAI of each tree followed Taylor’s law but with differing exponents, which varied from 0.75 to 6.4. Divergence of BAI among trees increased with time, and it might be related to the local drought, as the highest BAI divergence occurred when the SPEI (standardized precipitation-evapotranspiration index) was approximately 0 (−0.3–0.3). Hourly dendrometer measurements confirmed growth divergence among individuals. Collectively, our study provides new information about the growth characteristics of longleaf pine, which may partially explain how this species persists and thrives in southeastern environments. Our current management strategy on longleaf pine forests, such as prescribed burning and genetics improvement efforts, needs to be adapted. Full article

(This article belongs to the Special Issue Environmental Signals in Tree Rings)

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18 pages, 8080 KB

Open AccessArticle

Spatial Distribution and Intraspecific and Interspecific Association in a Deciduous Broad-Leaved Forest in East China

by Jingxuan Wang, Zeyu Xiang, Dan Xi, Zhaochen Zhang, Saixia Zhou and Jiaxin Zhang

Forests 2025, 16(10), 1511; https://doi.org/10.3390/f16101511 - 24 Sep 2025

Abstract

The spatial distribution of plant species is a crucial indicator of the mechanisms driving competition or coexistence both within and between populations and communities. Analyzing these patterns provides essential insights into fundamental ecological processes and aids in evaluating ecological hypotheses. To study the [...] Read more.

The spatial distribution of plant species is a crucial indicator of the mechanisms driving competition or coexistence both within and between populations and communities. Analyzing these patterns provides essential insights into fundamental ecological processes and aids in evaluating ecological hypotheses. To study the spatial distribution of dominant tree species and their associations both within and among species, we established a 25-hectare forest plot in Lushan Mountain. We employed the g(r) function alongside three null models—complete spatial randomness (CSR), heterogeneous Poisson (HP), and antecedent condition (AC)—to analyze spatial patterns and assess species interactions at various life stages. Additionally, we examined the relationships between spatial distributions and environmental factors such as soil properties and topography using Berman’s test. Our results showed that all 12 dominant tree species exhibited significant aggregation under the CSR model; however, the scales of aggregation were reduced under the HP model. We also found evidence of aggregation among multiple species across different life stages and tree layers under CSR. Notably, this pattern persisted under the AC model but was limited to specific spatial scales. Furthermore, elevation, topographical convexity, and the total content of soil nitrogen (N) and carbon (C) were identified as statistically significant predictors of species distributions. Overall, these findings highlight that both biological and environmental factors play a vital role in shaping plant spatial patterns across different scales. Full article

(This article belongs to the Special Issue Modeling of Forest Dynamics and Species Distribution)

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14 pages, 1338 KB

Open AccessArticle

Impact of Trapping Programs for Ips typographus (Linnaeus) (Curculionidae: Scolytinae) on Predators, Parasitoids, and Other Non-Target Insects

by Matteo Bracalini, Andrea Martini, Lorenzo Tagliaferri and Tiziana Panzavolta

Forests 2025, 16(10), 1510; https://doi.org/10.3390/f16101510 - 24 Sep 2025

Abstract

The European spruce bark beetle, Ips typographus (Linnaeus, 1758), poses a significant threat to Picea abies (Linnaeus) Karsten, 1881 forests, with outbreaks often exacerbated by abiotic disturbances like the 2018 Vaia windstorm in the Italian Alps. Pheromone-baited traps are widely used for control, [...] Read more.

The European spruce bark beetle, Ips typographus (Linnaeus, 1758), poses a significant threat to Picea abies (Linnaeus) Karsten, 1881 forests, with outbreaks often exacerbated by abiotic disturbances like the 2018 Vaia windstorm in the Italian Alps. Pheromone-baited traps are widely used for control, yet their overall efficacy and potential side effects, particularly the incidental capture of non-target insects, remain debated. This study aimed to comprehensively assess the presence and composition of non-target insects in I. typographus pheromone traps, used for both mass-trapping and monitoring, in the affected Alpine regions. We took into account single monitoring traps (dry collection) and three-trap cross configurations for mass-trapping (with preservative liquid), collecting and morphologically identifying insect by-catch. Our results revealed a non-target proportion (excluding bark beetles) significantly higher in mass-trapping (4.15%) compared to monitoring (1.00%), with approximately half being natural enemies of bark beetles. Crucially, we report that bark beetle parasitoids were repeatedly caught, with Tomicobia seitneri (Ruschka, 1924) (the third most abundant non-target species) particularly well represented, and Ropalophorus clavicornis (Wesmaël, 1835) also detected, which is noteworthy given its ecological role despite its lower numbers. Our findings underscore the significant, previously underreported, capture of beneficial parasitoids and highlight the need for careful consideration of non-target catches in I. typographus pest management strategies. Full article

(This article belongs to the Section Forest Biodiversity)

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19 pages, 6095 KB

Open AccessArticle

Comparative Analysis of Potential Fire Behavior Among Three Typical Tree Species Fuel Loads in Central Yunnan Region

by Mingxing Liu, Yuanbing Yu, Weiming Chen, Ming Zhou, Jiaming Zhao, Biao Ye, Xilong Zhu, Shiying Xu, Chunyi He, Weili Kou and Qiuhua Wang

Forests 2025, 16(10), 1509; https://doi.org/10.3390/f16101509 - 24 Sep 2025

Abstract

Potential fire behavior varied significantly among tree species, directly influencing forest fire intensity and spread. To quantify these differences and evaluate species-specific fuel traits for fire management applications, this study conducted field surveys and sample collection in the Jin Dian Yuanbaoshan Forest Area, [...] Read more.

Potential fire behavior varied significantly among tree species, directly influencing forest fire intensity and spread. To quantify these differences and evaluate species-specific fuel traits for fire management applications, this study conducted field surveys and sample collection in the Jin Dian Yuanbaoshan Forest Area, Kunming, Yunnan Province. Using a combustion bed experiment, we simulated the burning behavior of Acacia dealbata, Alnus nepalensis, and Pinus armandii under windless conditions, recording ignition time, extinction time, flame height, spread rate, and calculating fire intensity. Comparative analysis revealed: (1) Fire intensity ranking: P. armandii needles > A. dealbata leaves > P. armandii branches > A. nepalensis leaves > P. armandii bark > A. dealbata branches > A. nepalensis branches > A. dealbata bark > A. nepalensis bark; (2) The biological firebreaks composed of A. nepalensis and A. dealbata in Yuanbaoshan exhibited effective flame-retardant performance; (3) Coarse woody fuels negatively affected prescribed burning intensity and effectiveness. By quantifying fire behavior differences among these species, this study provides scientific support for fuel management and fire-resistant species selection in central Yunnan, while offering practical guidance for prescribed burning strategies in the Jin Dian Yuanbaoshan Forest Area. Full article

(This article belongs to the Special Issue Fire Ecology and Management in Forest—2nd Edition)

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27 pages, 1062 KB

Open AccessArticle

Uncovering Seasonal Heterogeneity in Forest Ecosystem Valuation: Evidence from a Meta-Analysis with Experimental Insights

by Chulhyun Jeon and Danny Campbell

Forests 2025, 16(10), 1508; https://doi.org/10.3390/f16101508 - 24 Sep 2025

Abstract

Seasonal variation not only influences the ecological functioning of forest ecosystems but also alters the benefits people derive from them, ranging from physical to psychological restoration. Ignoring such variation in valuation risks, thereby producing seasonally biased and unreliable estimates, constitutes an issue that [...] Read more.

Seasonal variation not only influences the ecological functioning of forest ecosystems but also alters the benefits people derive from them, ranging from physical to psychological restoration. Ignoring such variation in valuation risks, thereby producing seasonally biased and unreliable estimates, constitutes an issue that previous valuation studies have largely overlooked. This study investigates the extent of seasonal bias in willingness to pay (WTP) for forest ecosystem services using a meta-dataset of 476 observations from Korea. Applying pooled, weighted, and robust mixed-effects models, we uncovered substantial seasonal heterogeneity through our analysis: WTP increases by 67% in autumn but declines by 18% and 65% in the summer and winter, respectively. The robust mixed-effects model provided the best empirical fit, highlighting the methodological value of explicitly modeling temporal effects in meta-regression. These results reflect seasonally differentiated engagement with forests and suggest that individuals implicitly recognize the temporal value of ecosystem services. Nevertheless, limitations remain, particularly the heterogeneity of research designs, survey methods, and elicitation formats, which may introduce variability and potential bias. Therefore, while seasonal differences are statistically significant, the results should be interpreted with caution. Extrapolating annual values from single-season data risks systematic distortion, especially when stated preference methods are used. Beyond methodological implications, the findings also underscore a broader point: seasonal rhythms shape not only ecosystem dynamics but also human well-being. Accurately valuing these shifting benefits is essential for making credible economic assessments and sustaining long-term reciprocity between people and nature. Full article

(This article belongs to the Special Issue Economic Research on Forest Ecosystem Services)

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27 pages, 3412 KB

Open AccessArticle

Exploring Preference Heterogeneity and Acceptability for Forest Restoration Policies: Latent Class Choice Modeling and Principal Component Analysis

by Chulhyun Jeon and Danny Campbell

Forests 2025, 16(10), 1507; https://doi.org/10.3390/f16101507 - 24 Sep 2025

Abstract

The restoration of forest ecosystems damaged by wildfires and pest outbreaks has become increasingly urgent. However, the public-good nature of forests, the involvement of diverse stakeholders, and the spatial variability of degradation present significant challenges to effective policy design. In particular, previous studies [...] Read more.

The restoration of forest ecosystems damaged by wildfires and pest outbreaks has become increasingly urgent. However, the public-good nature of forests, the involvement of diverse stakeholders, and the spatial variability of degradation present significant challenges to effective policy design. In particular, previous studies have largely examined these threats in isolation, and few have provided integrated economic analyses of their combined impacts. This gap underscores the need to better understand heterogeneous public preferences and their implications for restoration policy. To address this, we conducted a discrete choice experiment (DCE) with 1021 Korean citizens and applied a two-stage analytical framework combining principal component analysis (PCA) and latent class choice modeling (LCM). Five distinct preference segments were identified, each exhibiting substantial variation in willingness to pay (WTP) for restoration attributes. Policy simulations further revealed that public acceptance declines sharply at higher cost levels, highlighting the importance of setting realistic financial thresholds for broad support. While visual materials, consequentiality checks, and cheap talk scripts were employed to mitigate hypothetical bias, the limitations of external validity and potential sampling biases should be acknowledged. Our findings provide empirical evidence for tailoring restoration policies to different stakeholder groups, while also stressing the financial and institutional constraints of implementation. In particular, the results suggest that cost thresholds, citizen engagement, and awareness-raising strategies must be carefully balanced to ensure both effectiveness and public acceptance. Taken together, these insights contribute to evidence-based forest policymaking that is both economically efficient and socially acceptable, while recognizing the context-specific limitations of the Korean case and the need for comparative studies across countries. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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19 pages, 1994 KB

Open AccessArticle

Comparison of Plantation Arrangements and Naturally Regenerating Mixed-Conifer Stands After a High-Severity Fire in the Sierra Nevada

by Iris Allen, Sophan Chhin, Jianwei Zhang and Michael Premer

Forests 2025, 16(10), 1506; https://doi.org/10.3390/f16101506 - 23 Sep 2025

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Abstract

A sharp escalation in wildfire frequency, severity, and scale in the western United States calls for the creation of forests that are resilient in the future. One reforestation method involves clustering trees into groups of two to four, instead of creating evenly spaced [...] Read more.

A sharp escalation in wildfire frequency, severity, and scale in the western United States calls for the creation of forests that are resilient in the future. One reforestation method involves clustering trees into groups of two to four, instead of creating evenly spaced plantations, in an effort to increase structural heterogeneity and emulate natural regeneration patterns. There have been a limited number of studies on clustered plantations, and this study addresses this important research gap. In Eldorado National Forest in the Sierra Nevada, we compared growth and structure in several post-fire plantations, treated with and without pre-commercial thinning (PCT), and naturally regenerating stands. Using mixed-effects models, we tested for growth and structural differences between evenly spaced and clustered plantations, as well as comparing them to stands of naturally regenerating trees. Our results indicated that diameter and height growth were generally better maintained in the plantations compared to under natural stand conditions. When considering plantation arrangement, the annual basal area increment (BAI) thinning index ([BAI after thinning − BAI before thinning]/BAI before thinning) was generally higher in evenly spaced plantations (1.03) compared to clustered plantations (0.79). While high plant diversity would be important eventually from an ecological perspective, our study suggests that during the initial phases of plantation development, lower shrub diversity could assist with plantation establishment and growth. The frequency of yellow pines was an important, positively associated factor affecting BAI and height growth, but primarily in the high-elevation region, which demonstrates a facilitative legacy effect of prior stand composition. Our study highlighted the important legacy effect of prior stand density on the growth of yellow pines, but primarily in the low-elevation region, and only when the two plantation groups were examined. The negative association suggests that a lower initial density of plantations promotes better BAI growth and height growth after PCT. These findings thus have broad implications for effective post-fire restoration of young plantations to help ensure their future resilience to both post-fire restoration and climate change adaptation and biotic (i.e., plant competition) stress factors. Full article

(This article belongs to the Special Issue Post-Fire Recovery and Monitoring of Forest Ecosystems)

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18 pages, 2201 KB

Open AccessArticle

The Effects of Nitrogen Deposition and Rainfall Enhancement on Intraspecific and Interspecific Competitive Patterns in Deciduous Broad-Leaved Forests

by Liang Hong, Guangshuang Duan, Yanhua Yang, Shenglei Fu, Liyong Fu, Lei Ma, Xiaowei Li and Juemin Fu

Forests 2025, 16(10), 1505; https://doi.org/10.3390/f16101505 - 23 Sep 2025

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Abstract

Amid accelerating global nitrogen deposition, China has emerged as the world’s third-largest hotspot after Western Europe and North America. Disentangling how elevated N inputs interact with intensifying precipitation and silvicultural practices is therefore essential for forecasting forest responses to ongoing climate change. Taking [...] Read more.

Amid accelerating global nitrogen deposition, China has emerged as the world’s third-largest hotspot after Western Europe and North America. Disentangling how elevated N inputs interact with intensifying precipitation and silvicultural practices is therefore essential for forecasting forest responses to ongoing climate change. Taking advantage of the “canopy-simulated nitrogen deposition” platform in Jigongshan National Nature Reserve, we compared tree-level census data from 2012 and 2022 to quantify decadal shifts in neighborhood competition under seven nitrogen addition and rainfall enhancement regimes. After using ordered-sample clustering to identify eight competitors as the optimal neighborhood size, we applied the Hegyi family of competitive indices (CI, CI1, CI2, mCI, mCI1 and mCI2) to analyze competitive responses at three hierarchical levels: the entire stand, all surviving trees and three dominant species (Quercus acutissima, Quercus variabilis, and Liquidambar formosana). The results indicate: (1) Nitrogen addition and rainfall enhancement did not alter the dominant tree species of the stand, which remained primarily Q. acutissima, Q. variabilis, and L. formosana. (2) The competition indices based on all trees showed an upward trend, whereas those calculated for surviving trees and for dominant species declined markedly (surviving trees p < 0.1, L. formosana CI1 p < 0.05). (3) Although nitrogen addition treatments did not alter overall stand competition intensity, it relieved competitive pressure on surviving trees by suppressing interspecific interactions (CI2 and mCI2); intraspecific competition also weakened, but at a slower rate. (4) Interspecific competition intensity for surviving L. formosana decreased significantly, whereas competition indices for Q. acutissima and Q. variabilis remained statistically unchanged. (5) Nitrogen addition methods (canopy vs. understory) had no significant effect on competition indices, while nitrogen addition intensity exhibited a dose-dependent effect: high nitrogen addition significantly reduced interspecific competition intensity more than low nitrogen addition (p < 0.05). In summary, nitrogen deposition primarily regulates interspecific competition through concentration rather than pathway, providing scientific basis for adaptive management of broad-leaved mixed forests in transitional zones under sustained nitrogen deposition scenarios. Full article

(This article belongs to the Section Forest Ecology and Management)

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16 pages, 4849 KB

Open AccessArticle

Applying Electrical Resistance Tomography to Diagnose Trees Damaged by Surface Fire

by Kyeong Cheol Lee, Yeonggeun Song, Wooyoung Choi, Hyoseong Ju, Won-Seok Kang, Sujung Ahn and Yu-Gyeong Jung

Forests 2025, 16(10), 1504; https://doi.org/10.3390/f16101504 - 23 Sep 2025

Viewed by 97

Abstract

The Republic of Korea, with 64% forest coverage, is increasingly vulnerable to large-scale wildfires. This study employed electrical resistance tomography (ERT) to diagnose internal damage in Pinus densiflora trees following a surface fire in spring 2023. Of the 30 monitored trees, 5 died [...] Read more.

The Republic of Korea, with 64% forest coverage, is increasingly vulnerable to large-scale wildfires. This study employed electrical resistance tomography (ERT) to diagnose internal damage in Pinus densiflora trees following a surface fire in spring 2023. Of the 30 monitored trees, 5 died in 2023 and 6 more had died by 2024. Dead trees showed a 41% higher Bark Scorch Index (BSI) and a 10%–15% lower DBH and circumference than survivors. From July, ERT detected significant increases in high- (ERT_R) and medium-resistance (ERT_Y) areas, while low-resistance (ERT_B) regions declined. By September, ERT_R and ERT_Y were 2.2 and 1.9 times higher in dead trees. Maximum resistivity (Rs_max) rose 6.1-fold to 3724 Ωm. One year post-fire, healthy areas in dead trees dropped below 18%. These findings indicate that internal defects develop gradually and accelerate in summer and winter, correlating with thermal and freeze–thaw stress. Early diagnosis within two months post-fire was unreliable, while post-summer assessments better distinguished trees at mortality risk. This study demonstrates ERT’s utility as a non-destructive tool for tracking post-fire damage and guiding forest restoration under increasing wildfire threats. Full article

(This article belongs to the Section Forest Ecology and Management)

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23 pages, 1757 KB

Open AccessArticle

Discovering the Pathways from Urban Forests to the Subjective Well-Being of Citizens in Tehran

by Rahim Maleknia and Natalia Korcz

Forests 2025, 16(10), 1503; https://doi.org/10.3390/f16101503 - 23 Sep 2025

Viewed by 181

Abstract

Rapid urbanization reduces green space and increases urban stressors, yet the mechanisms linking urban forests to residents’ subjective well-being remain incompletely understood. This study examines how perceived access, perceived quality, visitation frequency, and satisfaction with urban forests relate to citizens’ subjective well-being in [...] Read more.

Rapid urbanization reduces green space and increases urban stressors, yet the mechanisms linking urban forests to residents’ subjective well-being remain incompletely understood. This study examines how perceived access, perceived quality, visitation frequency, and satisfaction with urban forests relate to citizens’ subjective well-being in Tehran. Using an online survey of 672 residents and structural equation modeling, this study estimates direct and indirect pathways among the constructs. The results show perceived access is the strongest predictor, raising visitation, satisfaction, and well-being, while perceived satisfaction is the most powerful direct driver of subjective well-being. Perceived quality positively affects well-being but with a smaller effect, and visitation frequency alone does not significantly improve well-being, underscoring that positive experiential factors such as satisfaction matter more than visit counts. The model explains 69.8% of variance in subjective well-being. This study refines the current theoretical foundation by integrating access, quality, frequency, and satisfaction within a single conceptual framework in a megacity context and directly comparing the relative strengths of accessibility versus quality as pathways to well-being. In the context of current knowledge it is among the first to test these comparative pathways using a large Tehran sample. Practically, these findings suggest that urban policy should prioritize equitable access and design that fosters satisfying experiences, not just increasing visit counts. Future research should use longitudinal or experimental designs, incorporate objective measures, compare multiple cities and types of green spaces, and explore moderators such as perceived safety, motivations for visiting, and place attachment to refine causal understanding and policy guidance. Full article

(This article belongs to the Special Issue Forest and Human Well-Being)

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21 pages, 10980 KB

Open AccessArticle

Assessing Spatiotemporal Dynamics of Poplar Plantation in Northern China’s Farming-Pastoral Ecotone (1989–2022)

by Jiale Song, Shun Hu, Ziyong Sun, Yunquan Wang, Xun Liang, Zhuzhang Yang and Zilong Liao

Forests 2025, 16(10), 1502; https://doi.org/10.3390/f16101502 - 23 Sep 2025

Viewed by 135

Abstract

The farming-pastoral ecotone (FPE) of northern China serves as a critical ecological transition zone, in which poplar plantations significantly contribute to afforestation for large-scale ecological restoration projects. Due to concerns about sustainability, precise monitoring of the spatiotemporal dynamics of poplar plantations is needed, [...] Read more.

The farming-pastoral ecotone (FPE) of northern China serves as a critical ecological transition zone, in which poplar plantations significantly contribute to afforestation for large-scale ecological restoration projects. Due to concerns about sustainability, precise monitoring of the spatiotemporal dynamics of poplar plantations is needed, but systematic research is lacking. This study investigated the spatiotemporal dynamics of poplar plantation area and growth status from 1989 to 2022, taking the Anguli Nao watershed, a typical region in the FPE of northern China, as an example. Firstly, by utilizing satellite images and the random forest classification algorithm, the poplar plantation areas were well extracted, with a high accuracy over 93% and extremely strong consistency as demonstrated by a Kappa coefficient larger than 0.88. Significant changes in poplar plantation areas existed from 1989 to 2022, with an overall increasing trend (1989: 130.3 km², 2002: 275.9 km², 2013: 256.0 km², and 2022: 289.2 km²). Furthermore, the accuracy of our extraction method significantly outperformed six widely used global land cover products, all of which failed to capture the distribution of poplar plantations (producer’s accuracy < 0.21; Kappa coefficient < 0.18). In addition, the analysis of vegetation growth status revealed large-scale degradation from 2002 to 2013, with a degradation ratio of 24.4% that further increased to 31.1% by 2022, satisfying the significance test via Theisl–Sen trend analysis and the Mann–Kendall test. This study points out the uncertainty of existing land cover products and risk of poplar plantations in the FPE of northern China and provides instructive reference for similar research. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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Forests, Volume 16, Issue 10 (October 2025) – 18 articles

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