Forests doi: 10.3390/f17080944

Authors: Chamodi Tharuni Mahanama Dissanayake Frederico Tupinambá-Simões Aitor Vázquez-Veloso Felipe Bravo

Integrating ground-based and aerial remote sensing for individual tree-level stem volume modeling remains underexplored in Mediterranean mixed forests, despite the growing need for cost-effective, automated forest inventory approaches. This study evaluated the combined use of Handheld Laser Scanning (HLS) and Unmanned Aerial Vehicle (UAV)-based Structure from Motion (SfM) photogrammetry for individual-tree stem volume modeling in a mixed stand in Castilla y León, Spain, dominated by Pinus halepensis, Pinus pinea, Quercus faginea, and Cupressus sempervirens. Two open-source HLS processing tools; the Forest Structural Complexity Tool (FSCT) and 3D Forest Inventory (3DFin), were compared for individual tree attribute extraction, with FSCT outperforming 3DFin across all species. Reference stem volumes were derived by applying species-specific Spanish National Forest Inventory (SNFI) allometric equations to FSCT-extracted diameter and height values. Random Forest models were then built using UAV-SfM crown metrics as predictors, testing two image overlap configurations: 80 × 80 F (80% front and side overlap) and 80 × 60 CF (80% front, 60% side, cross-flight). The 80 × 80 F configuration produced the best-performing model (R2 = 0.730), with 80 × 60 CF achieving comparable accuracy (R2 = 0.688), results confirmed by spatially independent leave-one-plot-out cross-validation (LOPO-CV R2 = 0.627 and 0.613, respectively). These results show that combining HLS and UAV-SfM through a predominantly open-source workflow offers a viable, reproducible approach to stem volume modeling in structurally complex Mediterranean mixed forests.

Forests doi: 10.3390/f17080943

Authors: Xinyu He Xin Ding Zhaopei Zheng Jing Hu Yu Lan

How modeled ecosystem carbon balance varies across the contrasting hydroclimatic zones of the Yellow River Basin, and whether its relationships with climate extremes differ among these zones, remain insufficiently understood. To address this knowledge gap, this study examined the spatiotemporal variability of modeled net ecosystem productivity (NEP) and its associations with temperature- and precipitation-extreme indices across three major ecological zones of the basin. Using satellite-derived NDVI, reanalysis climate data, and extreme climate indices for 2000–2022, we estimated NEP from CASA-simulated net primary productivity and modeled heterotrophic respiration, and assessed its temporal trends and climatic associations across three ecological zones. Three principal findings were obtained: (1) Over the 23-year study period, basin-wide NEP showed a statistically significant increasing tendency (β = 2.699 g C m−2 a−1), with a well-defined spatial gradient characterized by relatively lower productivity in the northwestern areas and elevated productivity toward the southeastern regions. (2) Modeled NEP increased across all four seasons. Summer showed the largest positive trend, whereas autumn and winter remained net carbon-release seasons but became progressively less negative over the study period. (3) The statistical associations between modeled NEP and extreme climate indices varied markedly across ecological zones. Extreme-precipitation indices were generally positively associated with modeled NEP in the arid northwestern zone, whereas several extreme-temperature indices showed predominantly negative associations in the northeastern monsoon-influenced region. Collectively, these findings provide model-based evidence of spatially differentiated associations between ecosystem carbon balance and climate extremes across the YRB, supporting regional ecosystem assessment and climate-adaptation planning.

Forests doi: 10.3390/f17080942

Authors: Laura A. E. Marshall Donald A. Falk

The potential for species distribution shifts in response to changing climate and altered fire regimes is a pressing concern across ecosystems. Species responses to climate and disturbance are expressed demographically as changes in survivorship and recruitment across gradients. We examined tree recruitment and radial growth response to climate along a biophysical gradient in a mixed-conifer forest in northern New Mexico, USA, in a watershed spanning from near the lower to upper elevation range for ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). We compared growth responses with climate variables and stand demographic patterns of the six major tree species present, to track shifts in species community composition and dominance. We found significant changes in species composition between mature trees and seedlings and saplings across Elevation–Aspect groups in several species, indicating incipient community change. Drought stress drove patterns of tree growth and species composition shifts at low elevations, while at higher elevations increased stand density following fire exclusion led to success of shade-tolerant species. Altered growth and demographic trends driven by drought and fire exclusion can serve as the mechanism for changing species distributions and community reorganization across landscape climatic gradients.

Forests doi: 10.3390/f17080940

Authors: Zihui Ye Shimin Yang Dongdong Wang Jinchu Luo Xu Li Hongfeng Chen

Pholidota chinensis is a valuable medicinal epiphytic orchid in China. While its ethnomedicinal importance is recognized, the environmental constraints governing its distribution and its response to future climate change remain insufficiently understood. This study employed the Maximum Entropy (MaxEnt) model to identify dominant environmental drivers and project current (1970–2000) and future (2041–2060, 2061–2080) potential climatically suitable habitats under SSP245 and SSP370 scenarios. Using 184 filtered occurrence records and 11 screened environmental variables, the model achieved high discrimination performance (mean AUC = 0.9614 ± 0.0092). Annual precipitation and precipitation of the driest quarter were identified as principal predictors, reflecting a coupled water-temperature niche. Future projections suggested an overall expansion of climatically suitable areas, particularly under SSP245, and a northwestward shift in suitability centroids. However, these projections represent potential climatic suitability rather than confirmed future distribution, as establishment depends on dispersal capacity, host availability, and microhabitat conditions. These findings provide a scientific basis for conservation prioritization and climate-adaptive cultivation planning.

Forests doi: 10.3390/f17080941

Authors: Xiaoming Xu Xiangdong Zhang Wu Li

The East Qinling Mountains serve as a key national ecological security barrier and the core water source area of the Middle Route of the South-to-North Water Diversion Project in China, where vegetation restoration is a core measure for regional ecological conservation. However, existing studies have mostly focused on the individual hydrological characteristics of either the litter layer or soil layer, with limited understanding of their synergistic effects and the functional differences among typical restored vegetation types. In this study, we investigated the hydrological functions of the litter layer and 0~40 cm soil layer across seven vegetation restoration types (five forest stands, grassland and farmland control) in the upper Danjiang River Basin, southern foot of the East Qinling Mountains. Key hydrological indicators, including litter biomass, water-holding capacity, effective interception capacity, soil porosity, organic matter content, and water storage capacity, were measured and comprehensively evaluated. Furthermore, we explored the underlying mechanisms by which vegetation restoration enhances the hydrological functions of the litter layer and soil profile. The results showed that vegetation restoration in the East Qinling Mountains significantly altered the litter characteristics, with broad-leaved, coniferous and mixed forests exhibiting higher litter thickness and biomass than grassland and farmland. Litter water-holding capacity varied markedly across vegetation types: Pinus tabuliformis-Quercus variabilis mixed forest (Pt-Qvmf) and Quercus variabilis Blume (Qv) showed the highest 24 h water-holding rate, water-holding depth, and effective retention depth, while grassland had the lowest values. Litter water retention followed a logarithmic function with soaking time, and water absorption rate exhibited exponential decay, with the semi-decomposed layer showing stronger water retention performance. Vegetation restoration effectively improved the soil bulk density, porosity, and water-holding capacity, with more pronounced amelioration in the topsoil layer, and significant differences were observed among vegetation types. Comprehensive evaluation via the entropy weight method revealed that Robinia pseudoacacia L. (Rp) and Pinus tabuliformis Carrière (Pt) had the optimal integrated hydrological functions of the litter-soil profile, while grassland and Platycladus orientalis (L.) Franco (Po) performed the poorest. Structural equation modeling further quantified the driving mechanisms: soil porosity was the dominant direct driver of soil hydrological function, while litter biomass exerted an indirect effect through a significant serial mediation pathway via root biomass, soil organic matter (SOM), and aggregate stability, with the model explaining 83% of the total variance in soil hydrological function. This study provides targeted theoretical support and practical guidance for vegetation restoration, optimal tree species configuration, and forest ecosystem management in the water source area of the South-to-North Water Diversion Project.

Forests doi: 10.3390/f17080938

Authors: Qianqian Zhan Beier Yuan Shuai Ling Yikang Sun

Urban forests are expected to cool cities, sustain biodiversity, and distribute access to nature; however, evidence is often produced at scales that do not align with implementation. This structured evidence map characterizes English-language articles and reviews indexed in OpenAlex from 2000 to 15 July 2026 and interprets the patterns through three implementation cases. Five title-and-abstract searches returned 1201 records; 1103 remained after DOI/OpenAlex-ID deduplication, and a precision-oriented deterministic screen retained a 140-record core set. Metadata and abstracts were coded for outcome, scale, method, and management/governance language. Management/governance-related language occurred in 110 records, thermal outcomes in 74, biodiversity in 59, and explicit equity terms in 26. Thirty-three records were coded at two or more specified spatial scales and seven at all three; 14 jointly contained thermal and equity codes. These are record-level co-occurrences, not evidence of causal integration. Melbourne, Singapore, and Barcelona illustrate, without serving as controlled comparisons, three ways to translate citywide ambition into precinct stewardship, connected networks, and heat-health priorities. Within the defined corpus, canopy cover alone is an incomplete performance measure. The review proposes a non-aggregated decision chain and indicator portfolio linking network configuration, neighborhood vulnerability, site-level forest quality, and funded stewardship. Because screening and coding used one index and title/abstract metadata, the numerical patterns describe explicit framing rather than evidence quality, independent studies, or pooled effects.

Forests doi: 10.3390/f17080937

Authors: Jing Lu Sreetheran Maruthaveeran Mohd Fairuz Shahidan Qunyue Liu Yaling Gao

Urban forest parks (UFPs) are important recreational green spaces within the urban built environment, contributing to urban residents’ subjective vitality and well-being. Understanding how the motivations of visitors to urban forest parks translate into positive psychological experiences is crucial for promoting urban residents’ physical and mental health. This study concentrated on the motives for visiting UFPs in Fuzhou, China, and developed a conceptual framework of “motivation–attitude–visit frequency–experience” to explore the pathways through which two dimensions of motivation influence leisure experience. Data were obtained from the responses of 573 visitors (242 males, 331 females) by using on-site intercept sampling, and online and on-site questionnaire survey at seven UFPs across the city. Serial mediation analysis was used to test the proposed relationships. The results showed that both extrinsic and intrinsic motivation positively predicted visit attitudes (β = 0.297, p < 0.001; β = 0.309, p < 0.001); only intrinsic motivation had a significant positive impact on visit frequency (β = 0.147, p = 0.031), and both visit attitudes and visit frequency positively predicted leisure experiences (β = 0.371, p < 0.001; β = 0.402, p < 0.001). Extrinsic motivation was entirely mediated by attitude, forming an indirect path to leisure experiences, whereas intrinsic motivation influenced experiences through both direct paths and indirect paths. The findings reveal the important role of attitude in linking visitors’ motivations with urban forest park use and experiential outcomes. Decision-makers should consider visitors’ motivational orientations and psychological responses in the planning, design, and management of urban forest parks to promote more meaningful and sustainable engagement with urban nature. With complexities of cities, more attention needs to be given to the use of longitudinal studies in future research to obtain comparable findings and further generalizations.

Forests doi: 10.3390/f17080936

Authors: Hak-Koo Kim Seonghun Lee Ji-Woo Jung Sun-Min Chae Jin-On Kwon Yong-Jin Kwon Chan-Beom Kim

With the acceleration of global urbanization, neighborhood green spaces have emerged as important carbon sinks. However, current urban carbon inventories frequently neglect the understory shrub layer owing to morphological heterogeneity and a lack of standardized allometric models. To address this limitation, we analyzed 13 major shrub species (n = 665) through whole-plant excavation. Hierarchical cluster analysis and linear discriminant analysis classified the 13 species into three functional morphological groups based on intrinsic morphological traits (basal stem density, root-to-shoot biomass allocation, and secondary radial growth capacity) (p < 0.001): small shrubs (Type I), large shrubs with high root-to-shoot allocation (Type II), and multi-stemmed sprouting shrubs (Type III). Standard models accurately estimated biomass for Type I species, whereas symbolic regression improved the prediction of the complex non-linear biomass allocation of Type II species. For Type III species, characterized by multi-stemmed growth and anthropogenic management, robust regression provided stable biomass estimates. Gompertz growth models predicted carbon sequestration trajectories, indicating that urban shrubs function as rapid carbon sinks during the early establishment stage. To facilitate practical application, we developed the Urban Forest Carbon Storage Calculator, which integrates Monte Carlo simulation and bootstrapping to generate 95% confidence intervals for species-specific biomass estimation. This study quantifies the overlooked carbon value of the urban shrub layer and provides a morphology-driven methodological approach and a practical tool for sustainable urban forest management.

Forests doi: 10.3390/f17080935

Authors: Andrej Halabuk Tomáš Rusňák Katarína Gerhátová Hubert Hilbert Matej Mojses Sabica Naz Jakub Tomes Ľuboš Halada

Seasonal forest phenology is commonly summarized as canopy greenness or phenophase timing, although leaf development also redistributes observed plant material through three-dimensional space. We evaluated whether repeated RGB-colorized handheld simultaneous localization and mapping (SLAM) can provide height-resolved trajectories of seasonal observed occupancy in adjacent Ailanthus altissima-dominated and native-dominated sectors of a young deciduous forest. We acquired 149 scans on 25 dates from March 2025 to March 2026 at six permanent locations. Point clouds were restricted to date-invariant common support, normalized to a March terrain model, and voxelized at 0.20 m. New occupancy was referenced to the union of two strict March leaf-off scans. A weakly supervised foliage likeness proxy combined geometry-first pseudo-labels with relative color, intensity, and local three-dimensional features; its outputs were interpreted as relative scores rather than leaf fraction, LAI, or biomass. The strongest and most persistent invaded positive signal was localized to 2–4 m. Continuous-time models supported the integrated 1–5 m contrast from late April through October, whereas formal support for the 5–12 m crown domain was limited to the late season invaded positive phase; the earlier native positive crown feature remained descriptive. Height-integrated SLAM showed broad seasonal concordance with intercepted PAR (rrm = 0.881), GCP-linked Sentinel-2 EVI2 (rrm = 0.670) and the five-date litterfall comparison (rrm = 0.914). However, correlations of the invaded minus native trajectories were positive but imprecise. The independent observations therefore supported the broad seasonal cycle rather than the detailed sector-specific or height-specific pattern. The workflow provides a conservative means of localizing relative seasonal observed occupancy in three dimensions, but the resulting contrasts remain site-specific and hypothesis-generating.

Forests doi: 10.3390/f17080934

Authors: Hyo-Vin Ji Geon Lee Jin-Woo Park

Wildland–urban interface (WUI) wildfires pose escalating threats worldwide due to climate change and urban expansion. Gangneung City, South Korea, accounts for approximately 56% of provincial wildfire damage over the past decade, highlighting the need for systematic WUI susceptibility assessment. This study developed a high-resolution wildfire susceptibility map for forest-adjacent areas in Gangneung City and validated it using historical fire records from 1991 to 2024. Thirteen susceptibility factors in four categories—forest–topographic, anthropogenic, accessibility, and fire-response—were weighted using a literature-based frequency method and mapped at 10 m × 10 m resolution into four grades (Grade 1: very high to Grade 4: low). High-susceptibility zones (Grades 1–2) covered 51.7% of the total area, rising to 91.9% within interior forest-adjacent zones. Of 206 historical fires, 139 (67.5%) occurred within forest-adjacent zones; 93.4% of interior-zone fires fell in high-susceptibility areas. Hikers’ negligence was the leading ignition cause (30.8%). This is the first South Korean study to map WUI wildfire susceptibility distinguishing interior and exterior forest-adjacent zones at 10 m resolution, with spatial validity confirmed through over 30 years of fire records. The map provides a practical decision-support tool for spatially targeted WUI fire prevention and resource deployment at the local government level.

Forests doi: 10.3390/f17080933

Authors: Marizete Chaves de Cerqueira Eraldo Aparecido Trondoli Matricardi Aldicir Scariot Ricardo de Oliveira Gaspar Carlos Moreira Miquelino Eleto Torres Dietrich Darr Juscelina Arcanjo dos Santos Eder Pereira Miguel

Land-use and land-cover (LULC) change is a major driver of ecosystem degradation and ecosystem service loss in tropical landscapes. This study assessed the impacts of LULC changes between 1985 and 2023 on the potential of different LULC classes to supply ecosystem services in the Upper Rio Pardo Basin (Rio Pardo and Rio São João do Paraíso watersheds), northern Minas Gerais, Brazil. LULC data from the MapBiomas Project were used to quantify transitions among LULC classes within the study area. The potential supply of ecosystem services was assessed using the Burkhard matrix, adapted to local environmental conditions and informed by expert knowledge, while the relative importance of ecosystem services was evaluated through a participatory assessment involving local communities. The expansion of pasturelands and commercial forest plantations was identified as the primary driver of ecosystem service loss in the study region. Native ecosystems showed the highest potential to provide regulating, supporting, provisioning, and cultural ecosystem services, particularly water regulation, soil protection, carbon sequestration, and biodiversity conservation. In contrast, anthropogenic land uses were primarily associated with provisioning services and showed limited capacity to sustain regulating and supporting services, indicating clear trade-offs between production and ecosystem functioning. Local communities identified water-related services as the highest priority, followed by climate regulation, soil fertility, and food provision. These findings demonstrate the value of integrating expert-based and participatory approaches to ecosystem service assessment and provide a basis for territorial planning strategies that prioritize the conservation and restoration of native vegetation, particularly in hydrologically sensitive areas.

Forests doi: 10.3390/f17080932

Authors: Zina Soltani Anastasia Popova Mayasar I. Al-Zaban Hammadi Achour Kaouther Mechergui Melek Mallat Wahbi Jaouadi

Coastal dune ecosystems play an essential role in shoreline stabilization, biodiversity conservation, and carbon storage, but they are increasingly threatened by human activities and climate-related disturbances. This study assessed long-term forest vegetation dynamics in restored coastal dune ecosystems in northwestern Tunisia, integrating a 30-year Landsat dataset (1994–2024) with Random Forest classification. We quantified changes in forest and shrubland cover, evaluated the effectiveness of dune stabilization reforestation (Pinus pinea and Acacia spp.), and assessed the impact of the 2023 wildfire on forest biomass and carbon stocks. The findings demonstrate that reforestation efforts reduced mobile sand areas by 42.9% over three decades, with 78% of the sand loss attributable to vegetation stabilization. When infrastructure-affected areas were excluded, sand decreased by 64.7%, confirming genuine reforestation effectiveness. The 2023 wildfire caused substantial forest biomass losses in the reforested pine stands (264.19 t·ha−1) and carbon reductions (124.17 t·ha−1). These losses reflect the high vulnerability of Mediterranean coastal forests to wildfire disturbances under recurrent summer drought and increasing temperatures. The study emphasizes the importance of long-term remote sensing time-series for coastal forest management and restoration planning in Mediterranean ecosystems.

Forests doi: 10.3390/f17080931

Authors: Zhibin Li Zhen Liu Cuiying Zhou

The Nanling region serves as a critical ecological barrier in South China, playing a vital role in developing and maintaining the region’s distinct ecological characteristics. However, in recent years, ecological degradation has emerged in certain areas. Current research on the changing dynamics of the Nanling ecosystem remains insufficient, particularly regarding the synergistic effects of driving factors on ecological change, hindering effective ecological restoration efforts in the region. This study evaluated the spatiotemporal patterns of vegetation differentiation and their driving factors in the Nanling region by integrating multi-source remote sensing data from 2011 to 2023 with various relevant statistical methods. The results indicate that the areas with significant vegetation changes in the Nanling region can be divided into five major zones. Most vegetation shows an overall growth trend (89.8%), but there are areas of vegetation degradation (6%) in the eastern and western regions. Mountain vegetation dynamics are regulated by elevation-driven climatic gradients. Human activities play a dominant role in the distribution of vegetation in valley and basin areas, while terrain and soil thickness are important driving factors affecting vegetation. The direct effects of climate and soil properties are relatively minor. Overall, the ecological landscape of the Nanling region is the result of the combined effects of topography, climate, rock properties, soil, and human activities. This study provides a scientific basis for ecological restoration and spatial management in degraded areas of the Nanling region.

Forests doi: 10.3390/f17080930

Authors: Yaqi Chu Yating Li Yu Shi Na Huang Xuefeng Zhao

Faced with both global climate change and rapid urbanization, understanding how the built environment affects surface runoff is essential for strengthening urban hydrological resilience. However, elucidating the nonlinear and interactive effects of three-dimensional buildings and two-dimensional green spaces on surface runoff potential in urban blocks remains a scientific challenge for precise flood-mitigation spatial planning. Using six typical waterlogging-prone blocks in Shenyang as case studies, this study constructs a morphological index system for urban gray–green spaces and reveals the nonlinear effects of each index on surface runoff potential using an interpretable Random Forest (RF)–SHAP model. The results indicate that the RF model reliably captures the complex spatial patterns of simulated local surface runoff potential (R2 = 0.723–0.825). At the block scale, the surface runoff response exhibits a dual character: it is predictively dominated by three-dimensional morphological dominance and two-dimensional base regulation. Three-dimensional building morphology generally demonstrates pronounced unidirectional thresholds and high-value saturation in model prediction. In particular, when the core indicator, building spatial congestion degree (B_SCD), crosses a critical threshold, surface runoff potential rises sharply. The coefficient of variation in building height (B_HVC) shows a “V-shaped” reversal in areas of extreme surface runoff potential, whereas two-dimensional green space indicators display clear asymmetric critical points. Significant reductions in surface runoff potential appear only when green space scale (G_LPI), boundary complexity (G_LSI), or fragmentation (G_PD) exceed specific model-identified thresholds. Furthermore, the study demonstrates marked interactive effects between the morphologies of gray–green spaces. High surface runoff risk from dense, large buildings can be substantially offset by large green space patches (G_LPI) with highly complex boundaries (G_LSI). The advantage of vertically staggered buildings (B_HVC) requires a green space base with low fragmentation (G_PD) to realize a gray–green synergistic mitigating effect. These findings provide theoretical and methodological support for enhancing the hydrological resilience of urban blocks.

Forests doi: 10.3390/f17080929

Authors: Xiangling Lei Haihui Chen Yiqing Chen Zongzhu Chen Juzhi Liang Shaofeng Su Zhipan Lin Junting Jia Liguo Liao Shouqian Nong

Ecological stoichiometric ratios of soil provide insights into the interactions and limitations among elements. This study examined the nutrient characteristics K, N, and P stoichiometric ratios in the soils collected from three distinct shelter forests (Casuarina equisetifolia, secondary forest, and Cocos nucifera) in a tropical coastal region of Hainan Province, China. Significant differences were observed among forest types in terms of stoichiometric ratios and nutrient levels in soil (p < 0.05). This may be related to the high species diversity in secondary forests and the complex composition of litter. soil nutrient levels in the secondary forest were higher than those in C. equisetifolia and C. nucifera. The effects of soil nutrient factors on soil ecological stoichiometric ratios differed across shelterbelt types. Soil organic matter, total potassium, available potassium, and ammonium nitrogen content substantially influenced the N:P, K:P, and N:K ratios (Q2 > 0.5). Soil TN content was highly significantly positively correlated with N:P, N:K, in C. equisetifolia and C. nucifera (p < 0.01), whereas in the secondary forest, it was highly significantly positively correlated with SOM and NH4+-N (p < 0.01). These results reflecting the complexity of nutrient cycling as well as the interdependence and mutual regulation between vegetation and soil in coastal shelter forest ecosystems.

Forests doi: 10.3390/f17080928

Authors: Bouthaina Sayad Oumr Adnan Osra Ebaa K. Khan Hatem A. Nojoum Mohanad A. Alfelali Amina A. Alrehaili Wajdy S. Qattan Mohammad A. Almahdi

Urban areas face increasing challenges related to heat stress and urban heat islands, necessitating effective strategies for microclimate regulation and thermal comfort enhancement. This study investigates the cooling effect of three tree species, Ficus retusa, Ficus benjamina and Fraxinus spp. (Ash trees), on urban microclimates and thermal comfort in downtown Annaba, Algeria, during the summer. The methodology comprises two complementary methods. First, field measurements of air temperature (Ta), relative humidity (RH), and wind speed (Ws) were recorded hourly from 9 a.m. to 9 p.m. Second, collected data was inputted into the ENVI-met microclimate model to simulate various urban canopy scenarios. Microclimate variations, including air temperature (Ta), mean radiant temperature (Tmrt), relative humidity, wind speed, and the Physiological Equivalent Temperature (PET) index, were computed over a 13 h period, from 9 a.m. to 9 p.m., to examine the cooling effect of each species and their impact on outdoor thermal comfort. The results demonstrate the notable cooling effect of Ficus species and Fraxinus spp. with Ficus species generally exhibiting larger reductions in air temperature (0.9 °C to 2 °C) and PET index (7.3 °C to 7.7 °C), and higher increases in relative humidity (5.6% to 6.8%) compared to Ash trees.

Forests doi: 10.3390/f17080927

Authors: Sergey N. Gorbov Nikita V. Shevchenko Nadezhda V. Salnik Suleiman S. Tagiverdiev Yulia V. Dzigunova Svetlana A. Tishchenko Elena V. Gershelis Vyacheslav V. Kremenetskiy Alexander V. Olchev

Sub-Mediterranean ecosystems along the northeastern Black Sea coast remain insufficiently studied despite their importance for the regional carbon cycle and their sensitivity to human disturbance. This study presents an exploratory case study of aboveground biomass carbon stocks in two contrasting plant communities at the carbon-monitoring supersite of the Southern Branch of the Shirshov Institute of Oceanology RAS in Gelendzhik, Russia. The aboveground observations were interpreted together with soil carbon stocks and greenhouse gas fluxes previously reported for the same permanent plots. The investigated communities comprised a terraced pine–oak plantation (SP1) and a natural pubescent-oak shiblyak (SP2). Vegetation was surveyed using the Braun-Blanquet approach. Tree biomass was estimated using the generalized allometric equation of Chave et al., while aboveground biomass was converted to carbon using carbon concentrations determined by elemental analysis of sampled plant tissues. Herbaceous vegetation and forest-floor material were quantified by elemental analysis. Within-plot spatial heterogeneity was visualized using Python-based radial-basis-function (RBF) interpolation for exploratory mapping of local carbon distribution. Because each vegetation type was represented by a single 400 m2 plot, all comparisons are site-specific and exploratory and should not be extrapolated beyond the investigated communities. The aboveground carbon density was 64.1 t C ha−1 in the terraced pine–oak stand and 16.1 t C ha−1 in the natural shiblyak. Woody biomass dominated the plantation, whereas litter and herbaceous vegetation contributed proportionally more to the carbon pool in the shiblyak. Previously published soil organic carbon stocks at the terraced site exceeded the measured aboveground carbon pool, whereas the natural rendzinas were characterized by substantial carbonate-associated inorganic carbon stocks. C/N ratios of organic substrates ranged from 11 to 100, indicating a pronounced variation in substrate quality: higher C/N values in woody and coniferous fractions were consistent with slower decomposition, whereas lower C/N values in herbaceous material were consistent with faster mineralization. Exploratory spatial mapping revealed within-plot variation in aboveground carbon of up to two orders of magnitude. Together, these site-specific observations provide the first integrated description of aboveground biomass carbon together with previously reported soil carbon pools for contrasting sub-Mediterranean vegetation on the northeastern Black Sea coast. Despite its exploratory nature, this study establishes a baseline for future replicated, spatially explicit investigations of ecosystem carbon dynamics in sub-Mediterranean ecosystems along the northeastern Black Sea coast.

Forests doi: 10.3390/f17080926

Authors: Linxin Duan Ya Li Jingjun Cheng Yongqin Liu Yunxia Gao

Nature reserves are among the regions with the richest forest and grass resources. They face dual pressures of protection and development. The non-timber forest products (NTFPs) industry combines ecological protection with economic development. This unique function provides a key solution to this contradiction. Drawing on the Theory of Planned Behavior (TPB), this study employs a structural equation model (SEM). We collected survey data from 361 farmers. These farmers live in communities surrounding Yunling Provincial Nature Reserve. We empirically examine how behavioral attitude, subjective norm, and perceived behavioral control influence their willingness to participate in the non-timber forest products (NTFPs) industry. The results show that subjective norm and perceived behavioral control significantly enhance participation willingness. Subjective norm emerges as the strongest predictor. In contrast, behavioral attitude has no significant effect. This suggests that external social pressure and perceived self-capability outweigh simple benefit expectations in shaping willingness. Accordingly, we recommend three measures. First, strengthen external support to translate attitudes into actual willingness. Second, leverage social networks to amplify subjective norms. Third, enhance farmers’ endogenous capacity to consolidate their participation base. These measures can foster a win–win outcome for ecological protection and community income growth.

Forests doi: 10.3390/f17080925

Authors: Oiva Hiltunen Ville Hallikainen Teijo Palander

The expansion of sustainable timber harvesting on peatland forests is important for forest owners, contractors, and the forest industry. This study investigated the effects of site-specific conditions on summertime harvesting operations and modeled the influence of a light nine-ton forwarder on rut formation. Three logistic mixed-effects models predicted peat surface disturbance (ROC = 0.60, 0.63, and 0.67), while a linear mixed model predicted rut depth when rutting occurred (R2 = 0.35). Rut formation was associated with the number of machine passes, cumulative load, groundwater table depth, peat layer thickness, and interactions between stand and harvesting variables. The results indicate that timber can be successfully forwarded from drained peatlands with limited bearing capacity when operations are adapted to local site conditions. The findings highlight the importance of road-network planning, load management, and operator decision-making in reducing rut formation. This modeling approach also supports operator training, thereby contributing to more sustainable timber harvesting on low-bearing-capacity sites.

Forests doi: 10.3390/f17080924

Authors: Snežana Stajić Ljubinko Rakonjac Violeta Babić Aleksandar Lučić Saša Eremija Suzana Mitrović Zoran Poduška Marija Milosavljević

Oak forests are important components of temperate forest ecosystems, yet the factors shaping understory plant diversity in Southeast European thermophilous oak forests remain insufficiently understood. This study investigates understory plant diversity in forests dominated by Quercus frainetto and Quercus cerris in the protected area of Kosmaj (Serbia) and examines its relationships with topographic, edaphic, and stand structure factors. Species richness, Shannon diversity, and Pielou’s evenness were used to characterize diversity patterns. Understory diversity was shaped by multiple environmental factors, with stand structure variables showing the highest independent contribution to species richness and Shannon diversity, whereas topographic variables were more closely associated with Pielou’s evenness. Humus content showed positive associations with Shannon diversity and Pielou’s evenness, whereas higher phosphorus and potassium availability showed negative associations with diversity indices, particularly Shannon diversity. Younger stands showed a tendency toward higher species richness, while Shannon diversity showed a similar but weaker pattern, although differences among stand age classes were not significant. Geological substrate was associated with variation in diversity patterns, with limestone showing greater species richness, whereas silicate substrates showed slightly higher Shannon diversity and evenness. These findings highlight that variation in understory plant diversity in thermophilous oak forests reflects the combined influence of stand characteristics, soil conditions, and topographic gradients, providing insights for biodiversity conservation and adaptive forest management through the maintenance of stand structural complexity, soil quality, and environmental heterogeneity.

Forests doi: 10.3390/f17080923

Authors: Udayalakshmi Vepakomma Isabelle Duchesne Magloire Loudegui Djimdou Arusharka Sen

Non-destructive assessment of wood quality in standing trees is increasingly important for value-based harvesting, precision forestry, and large-scale monitoring. Yet most operational approaches rely on destructive sampling or plot-level measurements that cannot be feasibly extended across extensive forest areas. A central barrier to scalable assessment is the spatial misalignment between external structural measurements and internal wood-quality responses which introduces systematic bias when conventional regression methods are applied. We introduce Regression based on Misaligned Covariates (RMC), a statistical framework that reconciles covariates and responses measured at different spatial locations by combining the Law of Total Expectation with kernel-based estimation of marginal relationships. RMC recovers height-dependent conditional means without requiring one-to-one spatial correspondence. RMC is demonstrated using two contrasting conifers, eastern white pine (Pinus strobus) and red pine (Pinus resinosa), with external covariates derived from high-precision manual measurements compatible with LiDAR-based structural characterization. Across leave-one-tree-out cross-validation, linear functional forms frequently outperformed the Normal model with a few exceptions, producing smoother and biologically interpretable knot-volume profiles aligned with known species-specific crown architecture. Model performance varied by stem zone and kernel choice when evaluated against the height-only baseline (m-hat). For white pine, the linear kernel achieved the lowest error in the clear stem (1.04 ± 0.04) and the Normal kernel performed best in the living crown (1.09 ± 0.08). For red pine, the linear kernel minimized error in the clear stem (1.28 ± 0.49), while the quadratic kernel yielded the lowest mean error in the living crown (1.24 ± 0.05). The resulting cumulative knot volume profiles captured species-specific differences in knot accumulation and aligned with known patterns of crown architecture and stem form. RMC establishes a mathematically formal foundation for estimating internal wood-quality attributes from external structural metrics for misaligned covariates. This framework offers a theoretical framework for future integration with automated LiDAR-derived datasets and provides a conceptual step toward non-destructive, stand-level wood-quality assessment.

Forests doi: 10.3390/f17080922

Authors: Tomasz Oszako Tadeusz Malewski Xiaoxiao Feng Barbara Kowalczyk Konrad Kowalczyk Sławomir Bakier Mengcen Wang Piotr Borowik Adam Okorski Justyna Nowakowska

Dispersal mechanisms of phytopathogenic fungi and oomycetes are critical components of forest disease dynamics. While wind and water are well-studied pathways, the role of large forest herbivores as passive vectors remains significantly overlooked. This study quantifies and compares the pathogen loads carried on the hooves and hair of wild red deer (Cervus elaphus) to evaluate their epidemiological potential. Swab samples were collected from the hooves and hair of harvested deer in the Czerwony Bór Forest District, Poland. Quantitative PCR (qPCR) assays targeting the ITS1 region were deployed to detect total fungal DNA, Alternaria alternata, Fusarium avenaceum/F. tricinctum, and several Phytophthora species. A linear mixed-effects model was implemented to statistically evaluate variations in pathogen loads across anatomical sampling locations while controlling for individual animal variability. Fungal DNA was detected in 87.5% of hoof samples, showing significantly lower Ct values (13.85–18.54) compared to fur samples (17.02–29.56), which exhibited a more patchy distribution (p = 0.016). Similarly, A. alternata transfer was highly favored by hooves (p < 0.001). Conversely, F. avenaceum was more frequently detected on hair. Among oomycetes, Phytophthora pseudosyringae was detected in all sampled animals, whereas Phytophthora cactorum occurred rarely, and other tested Phytophthora species were not detected. Wild deer carry DNA of multiple fungal and oomycete pathogens and may act as potential passive carriers within forest ecosystems. Hooves constitute the primary vector for soil-borne pathogens due to sustained contact with topsoil, whereas hair facilitates the movement of specific canopy or airborne taxa. These findings suggest that wildlife movements should be considered in future forest biosecurity assessments for comprehensive forest health management and for understanding pathogen exchange between forest and agricultural ecosystems.

Forests doi: 10.3390/f17080921

Authors: Gulbanu Sadyrova Aisha Taskuzhina Nazym Kerimbek Alexandr Pozharskiy Akmaral Nurmakhanova Kusaev Shaganbek Kuralai Orazbekova Yeraliyeva Zhanar Dilyara Gritsenko

Mountain ecosystems of the Northern Tian Shan harbor rare endemic plant species that are increasingly vulnerable to environmental change. This study assessed the ontogenetic stage composition, selected anatomical characteristics, and chloroplast genome features of Malus sieversii, Ribes janczewskii, and Ikonnikovia kaufmanniana. Field surveys included five populations and 971 recorded individuals: two populations of M. sieversii, one population of R. janczewskii, and two populations of I. kaufmanniana. Individuals were assigned to juvenile, immature, vegetative adult, and generative stages. The proportion of juvenile and immature individuals varied from 23.78% to 41.89% among populations, indicating substantial differences in the representation of early ontogenetic stages. Comparative anatomical analysis identified structural traits associated with adaptation to local environmental conditions. Complete chloroplast genomes were assembled and annotated, with sizes of 160,192 bp (M. sieversii), 157,432 bp (R. janczewskii), and 162,624 bp (I. kaufmanniana). All plastomes exhibited a conserved quadripartite structure and contained 131–132 genes and SSR loci with species-specific composition. Phylogenomic analysis placed M. sieversii within a well-supported wild apple clade, confirmed the distinct lineage of R. janczewskii, and supported the separation of I. kaufmanniana from Limonium. These findings provide new data and lay a basis for further studies to better understand the evolutionary distinctiveness and conservation relevance of endemic plant species in the Northern Tian Shan.

Forests doi: 10.3390/f17080920

Authors: Jiecheng Liao Yin Ren Shudi Zuo Xuejing Wu Birhanie Alemayehu Xin Liu

Regression-based aboveground biomass (AGB) prediction from Earth-observation data often compresses the upper tail of the biomass distribution, yet the relative effectiveness of geospatial residual correction and ensemble learning in fragmented mountain landscapes remains unclear. Thus, we compared the two paths for reducing high-value underestimation: geospatial residual reconstruction using empirical Bayesian kriging regression prediction, and feature-space optimization using Stacking ensemble learning. SHapley Additive exPlanations (SHAP) interpreted feature contributions, and quantile regression forests (QRF) converted high-AGB point estimates into prediction intervals. Results show that geospatial optimization brought limited gain because residual spatial autocorrelation was weak (Moran’s I = 0.10), whereas Stacking improved overall R2 from 0.75 to 0.79 and reduced high-AGB bias (AGB > 80 t/ha) from −13.56 to −5.49 t/ha. This improvement was mainly attributed to complementary heterogeneous learners, with XGBoost capturing the primary non-linear trends, SVR extrapolating to correct high-AGB errors, and RF providing minor marginal calibration. SHAP analysis suggests that LiDAR-derived cubic mean height (Elev_curt_mean_cube) was the dominant feature explaining high-AGB variability, with a threshold response consistent with biomass-height allometry. QRF achieved coverage of 92.8% with a mean interval width of 74.51 t/ha, while coverage in the high-AGB subset was 84.2% with a mean width of 90.50 t/ha. The proposed comparison-and-diagnosis framework provides an interpretable approach for selecting an appropriate correction pathway and supports forest carbon monitoring, carbon accounting, and management decisions in complex mountain ecosystems.

Forests doi: 10.3390/f17080919

Authors: Linan Yue Shuo Liu Song Yu

Salt stress severely limits plant growth, particularly in woody species. In this study, a time-course transcriptomic analysis (0–24 h NaCl treatment) revealed a clear time-dependent transcriptional reprogramming pattern in Betula platyphylla, characterized by rapid early activation followed by gradual stabilization. The response can be divided into three phases: early stress perception and signaling (1–3 h), mid-stage metabolic and hormonal reprogramming (5–9 h), and late-stage homeostasis and physiological adaptation (12–24 h). Early responses are dominated by signal transduction, the middle phase by metabolic reorganization and enhanced translation, and the late phase by redox and cellular homeostasis. Compared to the limited role of the Dehydration-Responsive Element-Binding protein (DREB) pathway, Abscisic acid (ABA) and Jasmonic acid (JA) signaling appear to play more central regulatory roles. Further analyses revealed the coordinated temporal activation of Reactive oxygen species (ROS), Salt Overly Sensitive (SOS), and ABA pathways: ROS shows an early burst followed by antioxidant activation; the SOS pathway regulates ion homeostasis via the Calcineurin B-like protein (CBL)-CBL-interacting protein kinase (CIPK) module; and ABA signaling progresses from biosynthesis to downstream transcriptional regulation. Protein interaction network analysis further identifies ABA signaling as a central hub integrating Ca2+ signaling, ROS metabolism, and ion transport. Overall, B. platyphylla responds to salt stress through a temporally coordinated regulatory network, providing new molecular insights into salt tolerance mechanisms in woody plants.

Forests doi: 10.3390/f17080918

Authors: Camila Fernández-Urrutia Leonardo Almonacid-Muñoz Bernardita Díaz-Mons Héctor Herrera Patricia Silva-Flores Alejandra Fuentes-Quiroz Cristiane Sagredo-Sáez Rodrigo Vargas-Gaete Giovanni Larama Andrés Fuentes-Ramirez

Wildfires are increasing in frequency and severity worldwide, with long-lasting effects on forest vegetation and fungal communities essential for seedling establishment and forest resilience. Nothofagus pumilio, the dominant tree of South American temperate forests, forms key fungal symbioses but shows limited post-fire regeneration. Root-fungal community responses in seedlings under long-term post-fire conditions remain unknown. We characterized root-associated fungal communities in N. pumilio seedlings growing in burned (eight years post-fire) and unburned forest of the southern Andes, using ITS1 metabarcoding. We assessed diversity, composition, and abundance of root-associated fungi, including ectomycorrhizal fungi and dark septate endophytes. Diversity and evenness were significantly lower in burned than in unburned forest, with no significant differences in richness or composition. The ectomycorrhizal genus Cortinarius was less abundant in burned-forest seedlings. In seedlings from burned forest, the dark septate endophyte Cadophora was significantly more abundant, whereas Exophiala and Cladophialophora were less abundant than in unburned forest. Despite these shifts, burned areas retained root-associated fungal taxa linked to plant-beneficial functions and shared most OTUs with unburned forest, indicating an incomplete but ongoing recovery. Further research should evaluate how these shifts affect early seedling performance, and assess the role of persistent beneficial taxa for restoration after wildfires.

Forests doi: 10.3390/f17080917

Authors: Yu Tang Yu Shi Yingjie Bu Di Wang Fusheng Ma

Urban green-space carbon sinks can contribute to reducing urban carbon emissions and supporting carbon-neutrality goals. This study examined the associations between urban green-space landscape patterns and above-ground carbon storage (AGCS) in Shenyang. The spatial distribution of estimated AGCS was mapped using ArcGIS and remotely sensed imagery. Pearson correlation analysis, geographically weighted regression, and an exploratory data-binning approach were used to evaluate associations between landscape pattern metrics (LPMs) and AGCS and to identify their thresholds. At the study-area scale, AGCS exhibited strong positive correlations with class area (CA) and largest patch index, weak negative correlations with patch density and landscape division index, and a weak positive correlation with Connectivity Index (CONNECT). These relationships varied among the three ring zones. Spatially, CA was positively associated with AGCS throughout the study area, whereas positive local coefficients for CONNECT occurred in 51.8% of the study area. The low- and high-carbon-storage thresholds were 7.26 and 10.79 for CA and 8.33 and 12.08 for CONNECT, respectively. Higher CA and CONNECT values above their low-carbon-storage thresholds were associated with a lower probability of a low-carbon-storage zone. These findings provide context-specific evidence that may inform urban green-space planning in Shenyang and offer a methodological reference for comparable case studies.

Forests doi: 10.3390/f17080916

Authors: Laura Lopes Maldonado Giovanna Camargo do Carmo Amedea Barozzi Seabra José Antonio Pimenta Halley Caixeta Oliveira

Studies conducted with crop species have demonstrated that seed nanopriming with nitric oxide (NO) donors is an effective strategy to enhance early seedling development. Given the limited information available on the application of this approach in trees, this exploratory study aimed to investigate the effects of seed priming with nanoencapsulated S-nitrosoglutathione (GSNO) on emergence, early growth and root hair traits of five native Atlantic Forest tree species (Heliocarpus popayanensis, Cecropia pachystachya, Cariniana estrellensis, Schinus terebinthifolia, and Senna macranthera). Seeds were primed with chitosan nanoparticles (NPs) containing different GSNO concentrations (0.1, 0.25, 0.5, 1, 2.5 and 5 mM), in addition to hydropriming and non-primed control treatments. Seedling emergence and growth parameters were evaluated. Seed priming with GSNO-loaded NPs promoted increases in primary and lateral root length and the root-to-shoot length ratio, although responses varied among species and concentrations. Heliocarpus popayanensis was the most responsive species, with optimal results obtained at GSNO concentrations between 1 and 2.5 mM. The treatment also promoted increases in root-hair incidence and/or length in C. pachystachya, C. estrellensis, S. terebinthifolia, and S. macranthera. Overall, the technique showed potential to improve the early development of Atlantic Forest tree seedlings under greenhouse conditions; however, its effectiveness is species-specific and concentration-dependent.

Forests doi: 10.3390/f17080915

Authors: Luiz Paulo Amaringo-Córdova Tatiana Mildred Ucañay-Ayllon Jefferson Alexander Rodriguez-Sotelo Hilter Fasabi-Pashanasi Cesar Mori-Montero Oscar Amado Ruiz-Torres Wilson Francisco Guerra-Arévalo Héctor Guerra-Arévalo Uriel Aldava-Pardave Rosario Marilú Bernaola-Paucar Ana Lucía Milagros Vásquez-Vela Edinson Eduardo López-Galán Jhinmy Karc Hemeryth-Bartra Kevin Isaac Rodriguez-Vasquez

The valorization of wood derived from thinning operations in tropical plantations represents an alternative to enhance the sustainability and profitability of forest production systems. This study evaluated the hygroscopic, physical, and machining properties of 13-year-old Simarouba amara Aubl. thinning wood obtained from a plantation established in the Peruvian Amazon. Two planting spacings (2 × 2 m and 3 × 3 m) and three longitudinal stem positions (base, middle, and apex) were analyzed using a factorial design and generalized linear mixed models. Planting density and longitudinal position significantly influenced (p < 0.05) most of the evaluated properties. The saturated moisture content increased from 96.17% at the base to 135.42% at the apex, whereas basic density decreased from 0.45 to 0.30 g cm−3. Volumetric shrinkage ranged from 10.19% to 14.81%, and the dimensional stability index varied between 1.66 and 1.91. The first principal component (PC1) explained 98.4% of the total variance and clearly differentiated the treatments. The wood exhibited excellent performance in planing and molding, good performance in drilling, and fair performance in turning, indicating strong potential for the manufacture of higher value-added products and for sustainable utilization in tropical plantation forests.

Forests doi: 10.3390/f17080914

Authors: Liting Pang Qian Luo Huajun Lin Jianchao Ye Linghua Lei Yaoping Lv

Understanding seasonal patterns of forest biogenic volatile organic compounds (BVOCs) is essential for clarifying their ecological functions and potential health benefits. In this study, BVOC samples were collected from ten representative forest stands in Caoyutang Forest Park across four seasons using adsorption tube sampling coupled with thermal desorption–gas chromatography/mass spectrometry (TD-GC/MS). Pronounced spatial and temporal variations in BVOC composition and relative abundance were observed among different forest stands. The number of detected BVOCs varied considerably among seasons, following the order autumn > winter > spring > summer, while relative BVOC abundance was highest in autumn and lowest in spring. Thujopsis dolabrata stands showed relatively high BVOC relative abundance in spring, whereas several mixed forest stands exhibited greater compound richness and relative abundance during autumn. Seasonal shifts in dominant BVOC groups differed among forest stands, with esters becoming prominent in Cunninghamia lanceolata–Hydrangea mixed stands during summer, while aromatic hydrocarbons and alkanes dominated many stands during winter. Across all samples, alkanes and esters represented major compound classes, whereas aromatic hydrocarbons, aldehydes, and esters contributed substantially to relative abundance. A total of 10 terpenoid compounds were identified, with camphene representing one of the major components, and a higher relative abundance of terpenoids was observed in Abies firma stands. Principal component analysis indicated distinct compositional patterns among Cunninghamia lanceolata-dominated mixed stands, highlighting the influence of associated tree species and stand structure on BVOC profiles. This study elucidates spatial and seasonal BVOC patterns of BVOC composition in relation to forest structure, providing a scientific basis for planning forest therapy bases and selecting therapeutic plant species in landscape design.

Forests doi: 10.3390/f17080913

Authors: Rodrigo N. Vasconcelos Eduardo Mariano-Neto Washington J. S. Franca-Rocha Deorgia T. M. Souza Willian Moura de Aguiar Luanna Maia Carneiro Mariana M. M. de Santana

Tropical forests sustain exceptional biodiversity and regulate global carbon and water cycles, yet degradation and incomplete recovery increasingly compromise these functions. We integrated bibliometric mapping with structured systematic synthesis to characterize research at the tropical-forest degradation–restoration interface, identify its most influential contributors and publications, and evaluate evidence on drivers, interventions, monitoring, and knowledge gaps. This study addresses three guiding scientific questions: (i) How has the field developed over time and across geographic space? (ii) Which authors, institutions, journals and publications have been most influential? (iii) What does the evidence indicate about degradation drivers, restoration strategies, monitoring approaches and knowledge gaps? Scopus and Web of Science were searched for peer-reviewed articles and reviews published from 1980 to 2025. After deduplication and PRISMA-based screening, 1075 publications were analyzed bibliometrically, and the 400 most-cited studies were coded against twenty predefined questions. Scientific output increased by 10.68% annually, with 483 publications appearing during 2020–2025. The corpus comprised 318 journals and 4470 authors. Forest Ecology and Management was the leading source (141 publications; 13.1%), while the twenty most productive journals accounted for 44.3% of the corpus. Brancalion P.H.S. was the most productive author (23 publications), followed by Chazdon R.L. and Tabarelli M. (20 each). Citation influence was concentrated: the twenty most-cited documents received 25.7% of all citations, led by Ribeiro M.C. (3339 citations), whereas Hua F. achieved the highest publication-year-normalized citation score among this group. Agricultural expansion, pasture establishment, and logging were the most frequently reported degradation pressures, but interactions among logging, fire, drought, and fragmentation were rarely quantified. Restoration evidence supported a context-dependent continuum from natural regeneration to assisted and active interventions, although planting and enrichment were more visible than direct passive–active comparisons. Carbon, biomass, plant diversity, and forest structure dominated outcome assessment, whereas fauna, ecological interactions, governance, and socioeconomic dimensions received less attention. Monitoring relied mainly on satellite imagery and field inventories, with limited evaluation of tool performance. Long-term trajectories and evidence from Africa, Southeast Asia, seasonally dry forests, and montane systems remained scarce. Overall, the field is rapidly consolidating but remains geographically and thematically uneven. Future research should quantify interacting degradation processes, evaluate multidimensional and long-term recovery, connect remote sensing with ecologically meaningful field indicators, and integrate governance and social conditions into restoration planning. The synthesis supports preventing further degradation and treating restoration as a context-specific complement, rather than a substitute, for protecting remaining native forests.

Forests doi: 10.3390/f17080912

Authors: Chang Li Fandeng Liu Jianghua Zhu Yiyang Gu Hongyan Guo Sen Wang Biping Deng Xianglan Song Tao Liu Xiaofeng Tan Junqin Zhou

Camellia oleifera Abel. is a typical self-incompatible plant, yet its molecular mechanisms have not been comprehensively elucidated, which constitutes the principal cause underlying the relatively low natural fruit set rate in C. oleifera. S-RNase belongs to the RNase T2 gene family and represents a class of glycoproteins specifically expressed in the style with certain “cytotoxicities” capable of degrading ribonucleic acid (RNA) in their own pollen tube cells, thereby inducing programmed cell death in pollen tube cells. To identify pistil S genes participating in the self-incompatibility response of C. oleifera, nine RNase T2 family genes were identified based on transcriptomic and whole-genome sequencing data of the camellia oil tree and designated CoRNS1–CoRNS9. Systematic evolutionary analysis revealed that CoRNS5, CoRNS7, and CoRNS8 exhibit close phylogenetic relationships with S-RNases of the Camelliaceae family, whereas CoRNS6 shows closer affinity with S-RNases of the Solanaceae family. Analysis of promoter cis-acting elements revealed that RNase T2 family genes are regulated by multiple hormones, including abscisic acid, methyl jasmonate, cytokinin, auxin, salicylic acid, and gibberellin, and possess MYB transcription factor-binding sites. Expression analysis revealed that CoRNS6 is expressed exclusively in the ovary; CoRNS5 is expressed at the highest level in the style, followed by lower levels in the petals, anthers, filaments, receptacle, and ovary; CoRNS1 is expressed in all tissues except anthers; and the other genes are expressed across various floral tissues. Ex vitro pollen culture system experiments demonstrated that the CoRNS1 and CoRNS5 recombinant proteins significantly inhibited the elongated growth of autogamous pollen tubes, whereas CoRNS7 significantly reduced the pollen germination rate. Fluorescence labeling revealed that treatment of autogamous pollen tubes with the recombinant proteins CoRNS1, CoRNS5, and CoRNS7 induced microfilament skeleton depolymerization and increased the Ca2+ concentration within the pollen tubes. Additionally, treatment with the CoRNS5 recombinant protein increased the reactive oxygen species (ROS) levels in autogamous pollen tubes. These findings suggest that RNase T2 family genes are involved in the self-incompatibility response in C. oleifera, with CoRNS1, CoRNS5, and CoRNS7 playing pivotal roles. Overall, our results not only offer a theoretical foundation for elucidating the regulatory network governing self-incompatibility in C. oleifera, but also furnish valuable genetic resources for future molecular breeding programs targeting improved self-compatibility and increased fruit yield.

Forests doi: 10.3390/f17080911

Authors: Ahmed Al-Mansi Abdullah Alwetaid Saleh Alzamanan Chiharu Miyamoto Abdullah Almuthibi Ahmed Alameen Mohammed Awad

Mangrove restoration is increasingly recognized as an effective nature-based solution for biodiversity conservation, climate-change mitigation, and coastal resilience. However, long-term evaluations of restoration outcomes remain scarce, particularly in arid coastal environments. This study assesses three decades of ecosystem recovery following the afforestation of Avicennia marina at Sajid Bay, Farasan Archipelago, Saudi Arabia. A total of 1050 seedlings were transplanted in 1994 into an unvegetated intertidal area and monitored using multi-temporal satellite imagery and Normalized Difference Vegetation Index (NDVI) analysis from 1994 to 2024. Results revealed a progressive expansion of mangrove cover to 15.48 ha over the 30-year period, corresponding to an average annual increase of approximately 0.516 ha yr−1. Spatial patterns of expansion were strongly influenced by local geomorphological and hydrodynamic conditions. Central areas characterized by low wave energy and stable sediments exhibited the highest rates of colonization and vegetation development, whereas peripheral areas exposed to greater hydrodynamic stress expanded more slowly. The establishment of reproductive stands enabled natural regeneration, transforming the original plantation into a self-sustaining mangrove ecosystem. The findings demonstrate that relatively small-scale afforestation efforts can trigger long-term ecosystem recovery when implemented under suitable environmental conditions. The transition from planted seedlings to a naturally regenerating mangrove forest highlights the importance of site selection, hydrodynamic suitability, and ecological processes in determining restoration success. This study provides rare empirical evidence of long-term mangrove recovery in an arid coastal system and offers a practical conservation framework for restoring degraded coastal habitats throughout the Red Sea region and other environmentally comparable coastlines.

Forests doi: 10.3390/f17080910

Authors: Milan Pernek Ivan Pilaš Marta Kovač

Severe windthrow events can create highly favorable conditions for bark beetle outbreaks by generating large quantities of weakened breeding material. This study investigated the population response of the Mediterranean pine engraver, Orthotomicus erosus Wollaston, following a microburst windstorm that struck Marjan Forest Park, an urban Mediterranean Aleppo pine (Pinus halepensis Mill.) forest in Split, Croatia, in July 2025. Approximately 2000 m3 of damaged timber remained in the forest until February 2026, enabling assessment of colonization dynamics and outbreak development. Field inspections, laboratory analyses, and pheromone trap monitoring were conducted between July 2025 and April 2026. Insect sampling was conducted in the field through bark inspections and pheromone trap monitoring. For log inspections, bark sections were carefully removed to expose galleries and immature stages beneath the bark. Observations focused on the presence of entrance holes, boring dust, maternal galleries, larval galleries, pupal chambers, exit holes, adults, and immature developmental stages. In addition, ten pheromone traps were installed shortly after the windthrow event. Trap catches were collected regularly, and the captured insects were examined in the laboratory, where O. erosus individuals were identified and counted under a stereomicroscope. Colonization of windthrown material began within two weeks after the disturbance, and infestation rates reached 94% of examined logs by December 2025. At that point, 86% of infested logs already contained exit holes, indicating successful completion of beetle development. Pheromone traps captured a total of 131,588 adults, with more than 88% recorded during spring 2026 and a pronounced maximum recorded catch occurring on 8 April 2026. The appearance of newly attacked standing trees in spring (April) 2026 confirmed rapid population expansion from fallen material to living hosts. Results demonstrate the exceptional outbreak potential of O. erosus following extreme climatic disturbances and emphasize the importance of rapid sanitation measures and continuous monitoring in Mediterranean pine forests under climate change conditions. Delayed salvage logging after severe windthrow can rapidly trigger an outbreak of O. erosus.

Forests doi: 10.3390/f17080909

Authors: Armin Niessner Göran Spangenberg Stefan Ehekircher Reiner Zimmermann Jürgen Schäffer Moritz Mauz Volker Hochschild Sebastian Hein

Climate change is increasing drought frequency and severity in Central Europe, with consequences for the productivity and stability of mixed broadleaf forests. We analyzed annual radial growth of European beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.) along a water-availability gradient on the Swabian Alb (southwestern Germany). At three nearby sites, 45 trees per species were sampled. Tree-ring chronologies were related to meteorological variables and integrated drought indices (PDSI/scPDSI, SMI). Extreme dry and wet years were identified from detrended growing-season indices, and event responses were quantified using resistance, recovery, and resilience metrics and their humid-year analogues. Annual growth variation was primarily site-driven rather than species-driven, highlighting strong control by local soil water availability. Correlation analyses showed that integrated drought and soil-moisture indices explained radial growth more consistently than single climate variables. Oak showed higher drought resistance than beech in several events, although the magnitude and significance of this difference depended on site and drought year. Resistance generally declined toward recent events, particularly at Site 2, while recovery tended to increase. Recovery did not consistently favor either species, and resilience remained broadly stable, except for a decline in beech during the most recent drought events. Overall, sensitivity to drought is jointly controlled by species identity and fine-scale site conditions: oak has a comparatively robust resistance advantage, whereas post-drought recovery and resilience are strongly context-dependent. These findings support site-specific species mixtures and silvicultural strategies to sustain forest function under increasing drought risk.

Forests doi: 10.3390/f17080908

Authors: Fei Xiao Jiaquan Liu Wenhao Li Jingyi Guo Qiong Zheng Yiqiang Wu Mingjie Guan Cheng Li Jiarong She

Adhesive technologies have expanded rapidly and are now widely employed across diverse industrial sectors. However, conventional wood adhesives emit substantial amounts of formaldehyde and rely on fossil-derived feedstocks, posing risks to human health and the environment. Developing sustainable, multi-functional bio-based adhesives has therefore become increasingly important. As a renewable, environmentally friendly, bio-based material, soy protein shows strong potential to replace formaldehyde-based adhesives in plywood. This review summarizes the molecular structure, bonding mechanisms, and recent advances in functional soy protein adhesives. Topics include bonding strength, water resistance, anti-mold and antibacterial performance, flame retardancy, and electromagnetic shielding. The review discusses theoretical foundations and application prospects for green adhesives and outlines opportunities to design and fabricate high-value, multi-functional bio-based composites.

Forests doi: 10.3390/f17080907

Authors: Xurui Lyu Zhili Yao Zhiying Lin Tao Luo Binghua Zhang Hui Chen Xinchen Chester Hong

The rapid growth of UAV use in urban logistics, infrastructure inspection, emergency response, and campus services has made low-altitude flights more common in residential environments. Previous studies have mainly examined aircraft acoustics, flight conditions, building transmission, or listener responses. Repeated field evidence on UAV noise under contrasting canopy-site configurations remains limited. This study compared UAV noise under low-canopy (<8 m) and tall-canopy (>15 m) conditions at a six-storey campus residential area with a regular row-type layout. The two focal sites had similar building layouts, façade conditions, measurement positions, flight altitudes, and source–receiver geometry. They differed mainly in tree height and canopy density. We tested a DJI Mavic 2 Pro and a DJI Matrice 200 V2 in three independent hovering trials for each condition. We measured sound levels using Class 1 sound level meters. We also compared indoor and outdoor exposure. The analysis included one-third-octave-band spectra from representative recordings, descriptive psychoacoustic indicators, 118 valid questionnaires, principal component analysis, and exploratory empirical Bayesian kriging based on 15 measurement points. At the outdoor focal sites, the Matrice 200 showed a LASmax 10.0 dB higher under the tall-canopy condition. Its LAeq was 2.7 dB higher, whereas its L90 was 10.5 dB lower. This pattern indicates a wider, more intermittent sound-level distribution rather than a uniform increase. The Mavic 2 outdoor LAeq was 5.0 dB higher under the tall-canopy condition. Indoor differences varied by UAV model, window condition, and acoustic indicator. Higher transient sound levels and stronger psychoacoustic responses were associated with greater annoyance. EBK interpolation was used to visualize spatial heterogeneity. The assessment framework may also support studies in campus dormitory areas and row-layout multi-storey residential compounds with similar spatial features. The findings suggest that canopy-site configuration, building enclosure, UAV characteristics, and flight geometry should be assessed together.

Forests doi: 10.3390/f17080906

Authors: Marcela Rosas-Chavoya José Luis Gallardo-Salazar Roberto A. Lindig-Cisneros Cuauhtémoc Sáenz-Romero

Climate change has increased the frequency of hotter droughts and forest decline processes, highlighting the need for monitoring methodologies capable of detecting loss of vigor on the individual-tree scale. Pinus pseudostrobus is an economically important species in the temperate forests of the indigenous community of Nuevo San Juan Parangaricutiro, Michoacán. The aim of this study was to evaluate the elevational and thermal factors associated with the spatial and temporal variability of P. pseudostrobus vigor by integrating multispectral, LiDAR, and land surface temperature (LST) data. Five multispectral flights were conducted using unmanned aerial vehicles (UAVs) between June 2023 and June 2024, along with one LiDAR flight in April 2024, across an elevational gradient ranging from 2150 to 2920 m. High-resolution orthomosaics, NDVI and LCI indices, a canopy height model, and an object-based classification using Random Forest were generated. LST was obtained from Landsat 8–9 imagery in Google Earth Engine using the Statistical Mono-Window algorithm. Spectral, thermal, and elevation values were extracted at the individual-tree level. The classification achieved an overall accuracy of 69.6% and enabled the identification of 28,585 P. pseudostrobus individuals. NDVI and LCI varied significantly among periods, elevations, and their interaction. The lowest values of vigor were recorded in lower elevation areas, particularly in June 2023, April 2024, and June 2024. In addition, both indices decreased as LST increased, showing strong negative relationships for NDVI (R2 = 0.96) and LCI (R2 = 0.86). Individuals located at the lower elevational limit showed greater vulnerability to thermal stress.

Forests doi: 10.3390/f17080905

Authors: Seo Yeong Jo Tamirat Solomon Hyun Shik Moon

Historic landscape forests within cultural heritage sites represent a distinct category of urban green space that provides critical ecosystem services under strict conservation constraints. This study applied i-Tree Eco v6.0 to quantify the ecosystem services of the historic landscape forest of Jinju Fortress (Jinjuseong; Historic Site No. 118), South Korea, with focus on species-level contributions. A total of 822 trees representing 30 species were inventoried across 1.272 ha of tree cover. Zelkova serrata was the dominant species (importance value = 57.8) and contributed disproportionately to all ecosystem service categories, accounting for 40.7% of air pollutant removal, 61.3% of carbon storage, 58.2% of carbon sequestration and oxygen production, and 55.4% of avoided runoff. The forest removed 123.1 kg yr−1 of air pollutant Korean Won (KRW 8.834 million yr−1), stored 200.7 t (KRW 138 million), sequestered 8.834 t/yr (KRW 6.09 million/yr), produced 23.56 t/yr−1 of oxygen, avoided 10,413.7 L yr−1 of runoff and had a structural replacement value of KRW 1.63 billion. Beyond providing a species-level baseline for evidence-based management, this study introduces the concept of Heritage Ecosystem Service Efficiency (HESE) and the Species Ecosystem Service Dominance Index (SESDI), offering transferable frameworks for evaluating and managing ecosystem service performance in conservation-constrained heritage forests.

Forests doi: 10.3390/f17080904

Authors: Jingwen Wang Linsheng Zhong

Eco-compensation is not only an important supplementary source of funding for ecological conservation in national parks, but also an important mechanism through which ecological beneficiaries share the costs of national park conservation. In the context of the public welfare of national parks, free admission does not imply the absence of responsibility. Therefore, it is essential to strengthen tourists’ awareness of ecological conservation for national park management. Taking Wuyishan National Park as the study area, this study employed a questionnaire survey, distributed 630 questionnaires in total, and obtained 582 valid responses. The contingent valuation method (CVM) and a multiple-bounded dichotomous choice (MBDC) design were used to examine tourists’ willingness to pay (WTP) for eco-compensation and its influencing factors: (1) The tourists’ estimated average WTP for eco-compensation in Wuyishan National Park is approximately ¥451.72, which is higher than the total cost of admission and basic experience activities in the park. It implies that tourists have a relatively high willingness to pay for eco-compensation in the national park. (2) Based on Value–Belief–Norm (VBN) theory, the hierarchical OLS regression results showed that personal norms (β = 0.636, p < 0.01), awareness of consequences (β = 0.259, p < 0.01), and ascription of responsibility (β = 0.277, p < 0.01) were positively associated with lnWTP. The strength of these associations varied across VBN dimensions, with personal norms showing the strongest positive association with tourists’ WTP for eco-compensation. (3) Income differences have a clear effect on WTP. Higher-income tourists reported greater WTP, which was more strongly associated with awareness of consequences and personal norms, whereas lower-income tourists were more responsive to environmental values and ascription of responsibility. This study identifies an association between tourists’ environmental responsibility and willingness to pay for eco-compensation in the context of national park tourism. The findings offer empirical support for policy measures to regulate tourist behavior, enhance national park revenue, and reinforce the public welfare function of national parks.

Forests doi: 10.3390/f17080903

Authors: Hui Shen Zirui Tang Wei Wang

This study presents a controllable alkaline degradation strategy for preparing biomimetic archaeological Chinese fir through potassium hydroxide (KOH) impregnation, addressing the limitations of scarce and heterogeneous authentic archaeological wood for conservation research. Four KOH concentrations (5%, 10%, 20%, and 30%) combined with different treatment cycles (2–6 cycles) were applied to induce controlled degradation states under laboratory conditions. The results demonstrated that KOH concentration and treatment cycles effectively controlled the structure–property evolution of Chinese fir. Mass loss increased to 42.14%, while maximum water content reached 427.35%, accompanied by reductions in oven-dry and basic densities. X-ray diffraction analysis revealed a decrease in cellulose crystallinity from 34.10% to approximately 24%–26%, indicating partial disruption of cellulose crystalline domains, while Fourier transform infrared spectroscopy confirmed preferential degradation of hemicellulose through alkaline hydrolysis and relative preservation of lignin structures. Scanning electron microscopy further demonstrated tracheid deformation, lumen collapse, and enhanced pore connectivity after severe treatment. Based on the combined evaluation of physical, chemical, mechanical, and microstructural parameters, a three-level biomimetic archaeological wood grading system was established to correlate KOH treatment conditions with different degradation states. This study provides a reproducible approach for fabricating standardized biomimetic archaeological wood models and offers a reliable platform for conservation material evaluation and degradation mechanism studies.

Forests doi: 10.3390/f17080902

Authors: Rui Zheng Yanhong Li Jiang Ai Chongru Shi Tortay Mereke Dilnur Tussipkan

Seasonal freeze–thaw processes are important disturbances regulating soil carbon cycling in mid- to high-latitude mountain ecosystems, yet the mechanisms underlying carbon-fraction transformation and greenhouse gas emissions across vegetation types remain unclear. Here, we investigated five typical vegetation types along a 400–1500 m elevational gradient on the southern slope of the Altai Mountains. We measured topsoil organic carbon fractions, including particulate organic carbon (POC), mineral-associated organic carbon (MAOC), and dissolved organic carbon (DOC), extracellular enzyme activities, and CO2 and CH4 fluxes during the defrosting and melting periods to characterize vegetation-specific patterns of freeze–thaw-driven carbon stability. The results showed the following: (1) During the melting period, POC loss was significant in the low-elevation desert zone, riparian arbor forest, and floodplain meadow, with losses exceeding 90% in the latter two vegetation types. MAOC in the high-elevation mixed coniferous–broadleaf forest increased during the melting period. (2) The activities of carbon-acquiring enzymes, including CBH and AG, and the nitrogen-acquiring enzyme LAP generally decreased during the melting period, whereas the activity of the phosphorus-acquiring enzyme ALP increased in some vegetation types. This enzymatic shift may have partly constrained CO2 release per unit of mineralized organic carbon, but it did not reverse the overall increase in carbon emissions during the melting period. (3) Carbon dynamics during the defrosting period were mainly characterized by the temporary retention of mineralization-derived carbon in dissolved forms within the DOC pool under low-temperature conditions, followed by a shift during the melting period toward carbon emissions jointly regulated by hydrothermal conditions and extracellular enzyme activities. This study showed pronounced differences in carbon responses among typical vegetation habitats during freeze–thaw processes. These differences may be jointly influenced by vegetation composition, elevation, hydrothermal conditions, and soil properties, revealing an elevational pattern of carbon loss at low elevations and carbon-fraction reorganization at high elevations. These findings suggest that carbon-balance assessments in arid mountain regions should incorporate stratified identification and classified evaluation based on the distribution of dominant vegetation types.

Forests doi: 10.3390/f17080901

Authors: Francisco Alcaide Alexis Marchesini Paola Pollegioni Francesca Chiocchini Paola Mairota Marcello Cherubini Luca Leonardi Claudia Mattioni

Understanding patterns and processes affecting genetic diversity and structure of fragmented tree populations is essential for defining effective conservation strategies. Here, we investigate the genetic diversity of the Macedonian oak (Quercus trojana Webb 1839) across its entire Italian range by sampling 546 georeferenced trees from 30 forest stands. Using ten polymorphic nuclear microsatellite markers, we assessed within-population genetic variability and population structure, estimated effective population size (Ne), bottleneck signatures, and fine-scale relatedness among individual trees. Our results showed overall moderate genetic diversity, but marked variation emerged among populations and between two subregions. Populations in the North-Western Murge subregion exhibited lower allelic richness (Ar), critically small Ne (<50 in 12 populations), evidence of past bottlenecks, and higher pairwise differentiation, with three populations standing out as genetically distinct. Isolation by distance was significant only within the South-Eastern Murge subregion, suggesting contrasting demographic histories. Fine-scale relatedness analysis revealed higher within-site relatedness in North-Western Murge and a substantial proportion (30%) of related dyads across subregions, indicating large-scale connectivity due to natural or anthropogenic factors. Overall, our results reveal a complex scenario of historical and ongoing genetic erosion in some populations, particularly in the northern part of the range, alongside relatively high gene flow across the study area, especially in the south. We recommend prioritizing conservation actions for populations with critically low Ne and distinct gene pools, while maintaining genetic diversity hotspots and landscape connectivity.

Forests doi: 10.3390/f17080900

Authors: Dunja Demirović Bajrami Tamara Gajić Aleksandra Fostikov Milan M. Radovanović Jakub Löffler Taner Okan Coşkun Köse

Forest-based cultural heritage landscapes associated with traditional potash, tar, resin, and charcoal (PoTaRCh) production constitute valuable socio-ecological systems with considerable potential for sustainable tourism and rural development. However, little is known about how these destinations may evolve under future environmental, social, and governance uncertainties. The objective of this study was to identify the key drivers and critical uncertainties shaping the future development of PoTaRCh-based tourism systems in Europe by 2040 and to develop alternative scenarios to support strategic planning and adaptive governance. The research adopted the Intuitive Logics approach to scenario planning and the Scenario-Based Strategic Planning framework, combining a two-round Delphi study with 42 experts from 15 European countries and qualitative scenario development. Four key drivers were identified: forest ecosystem integrity, destination governance, community participation, and visitor experience and tourism demand. Their interaction resulted in five internally consistent scenarios: Forest Harmony, Guardians’ Forest, Tourist Forest, Forgotten Forest, and Regenerating Forest. The findings demonstrate that the resilience of PoTaRCh-based tourism systems depends on the dynamic interaction between ecological conditions, governance capacity, local stewardship, and tourism demand rather than on any single driver. To facilitate the practical application of the scenarios, the study also proposes a Scenario Monitoring Framework and Scenario Cockpit that translate qualitative scenario narratives into monitoring indicators for early detection of emerging development pathways. The study advances tourism futures research by providing one of the first comprehensive foresight analyses of forest-based cultural heritage tourism systems and offers practical guidance for destination managers and policy-makers seeking to strengthen the long-term sustainability and resilience of heritage landscapes.

Forests doi: 10.3390/f17080897

Authors: Javier Quille-Mamani German Huayna-Felipe Edwin Pino-Vargas Pablo Franco-León Fredy Cabrera-Olivera Jorge Espinoza-Molina Karina Acosta-Caipa Edgar Taya-Acosta José Huanuqueño-Murillo

Polylepis forests are the highest-elevation woody ecosystems on Earth and are severely threatened by climate change and land use, yet habitat models that go beyond binary presence/absence remain scarce. The current and future habitat suitability (2021–2100; CMIP6, four to five GCMs × four SSPs) of two co-occurring Andean species, Polylepis rugulosa and Polylepis tarapacana, was modelled with MaxEnt and Random Forest calibrated across their full range (Peru, Bolivia, Chile and Argentina) and clipped to the Tacna region of southern Peru. Internal spatial cross-validation was complemented by two external validations: 228 field-mapped stand polygons and 35 inventory plots (883 trees), the latter used to test whether suitability also tracks measured stand structure. Both algorithms performed well (AUC =0.78–0.94 across internal and external validation). Once within-plot non-independence and residual spatial autocorrelation were accounted for, no structural attribute was significantly associated with suitability: a positive suitability–multi-stemming trend persisted in Polylepis rugulosa (p=0.06–0.09) but not in Polylepis tarapacana, so this coupling is reported as a preliminary, hypothesis-generating result rather than as a validated predictive relationship. Within Tacna, suitable habitat above the maxSSS threshold is projected to contract by 17.4% for Polylepis rugulosa and by 100% for Polylepis tarapacana under SSP585 by 2081–2100 (MaxEnt ensemble; the near-total loss is unanimous across the contributing GCMs), revealing divergent climatic vulnerabilities. Reading suitability as a map of habitat quality rather than of habitat presence therefore remains a working hypothesis that larger plot networks and demographic data are needed to test.

Forests doi: 10.3390/f17080899

Authors: Mingbo Song Junxing Wang Changcheng Mu

Long-term atmospheric nitrogen (N) deposition can reshape forest soil N cycling, yet targeted evidence from functional gene bacterial communities remains particularly limited in cold-temperate coniferous forests. Here, we examined nifH- and nirK-harboring bacterial communities along a long-term simulated N-deposition gradient in a Larix gmelinii forest in the Greater Khingan Mountains, northeastern China. Four treatments had been applied since 2012: control (0 kg N ha−1 yr−1), low N (25 kg N ha−1 yr−1), medium N (50 kg N ha−1 yr−1), and high N (75 kg N ha−1 yr−1), with N supplied as NH4NO3. Soil inorganic N increased along the gradient; mean NO3−-N increased from 4.9 mg kg−1 fresh soil in the control to 8.1 mg kg−1 under high N. The nifH community showed mainly richness-related and exploratory biomarker responses, with observed richness highest under low N and no significant OTU-level whole-community separation. The nirK community showed a stronger medium-N-associated pattern: observed richness increased from 241.3 OTUs in the control to 421.3 OTUs under medium N, and OTU-level community structure differed among treatments. Taxonomic and biomarker patterns were also centered on medium N, but interpretation was constrained by the high proportion of unclassified or uncultured nirK sequences. These results indicate that nifH- and nirK-harboring communities responded differently to long-term simulated N deposition, with the clearest response in the nirK marker-gene community under medium N. Because this study is based on functional gene amplicon profiles, the results should be interpreted as community-profile evidence rather than direct evidence of N fixation, complete denitrification, gene expression, or N gas fluxes.

Forests doi: 10.3390/f17080898

Authors: Mareling García-Madrigal Dario Vasquez-Quesada Daniela Benavides-Villegas Ander Castander-Olarieta Itziar Aurora Montalbán Jason Pérez Paloma Moncaleán

Pinus radiata is a commercially valuable forest species whose productivity is increasingly threatened by climate change-related biotic and abiotic stresses, such as diseases, soil salinization, and rising temperatures. Using a sufficiently optimized somatic embryogenesis protocol for radiata pine as a starting point, this study aimed to evaluate the morphological and biochemical responses of embryogenic cell lines subjected to different elicitors, such as methyl jasmonate and tagatose, during proliferation, or to sodium butyrate at the maturation stage. The effect of various stresses, such as salinity and high temperatures, was evaluated at the proliferation and germination stages. Biochemical analyses, including measurements of total protein, hydrogen peroxide, and malondialdehyde contents were carried out in embryogenic tissues and somatic plants, and growth was also evaluated in these tissues and plants. This growth assessment led to the classification of plants according to their suitability for ex vitro planting. Several embryogenic cell lines were tested, and the response to elicitation or stress was found to be highly genotype-dependent; however, some trends were observed, particularly in terms of growth. These results suggest that somatic embryogenesis combined with stress priming or elicitor application may be a viable strategy for improving biotic and abiotic stress response in radiata pine.

Forests doi: 10.3390/f17080896

Authors: Elia Vangi Giovanni D’Amico Saverio Francini Costanza Borghi Alessio Collalti Daniela Dalmonech Marco Marchetti Gherardo Chirici Davide Travaglini Francesco Parisi

Climate change is expected to profoundly affect forest biodiversity, yet its impacts on saproxylic and non-saproxylic insects remain largely mediated by forest structure and management. Saproxylic beetles strongly depend on tree-related microhabitats (TreMs), which reflect stand development, deadwood dynamics, and habitat continuity. In this study, we assessed how future climate change may influence saproxylic beetle richness and TreM diversity across the Italian Apennines by integrating long-term field data from 336 forest plots with machine-learning models and the process-based forest model 3D-CMCC-FEM. Beetle and TreM richness were projected under a baseline current climate scenario (CCS) and two future climate scenarios (RCP4.5 and RCP8.5) until 2100. Gaussian process regression models with strong extrapolation performance were used to forecast richness trajectories based on simulated forest structural and climatic variables. Results show that host tree species and stand structural development are the primary drivers of both beetle and TreM richness, while differences among climate scenarios are comparatively small. Richness trajectories differed markedly among forest types: beech stands showed temporary mid-century increases under climate change scenarios, chestnut forests remained relatively stable, and silver fir and Turkey oak stands exhibited long-term declines or convergence toward lower richness levels. Patterns of TreM richness closely mirrored beetle richness, highlighting the central role of structural complexity and microhabitat availability. Overall, the effects of climate change on beetle diversity appear to be largely indirect, acting through forest growth, mortality, and microhabitat dynamics rather than through direct climatic constraints. These findings emphasize that forest management practices maintaining structural heterogeneity and microhabitat continuity can substantially mitigate climate-driven biodiversity changes, supporting the integration of TreMs into climate-adaptive forest management strategies.

Forests doi: 10.3390/f17080895

Authors: Wenqing Zheng Jinyu Fan Jiakai Zhao Yajing Duan Jie Meng Xi Zhang

The UBP gene family plays a key role in various physiological processes, including cell cycle regulation, DNA repair, and stress responses. UBPs have been identified and analyzed in several species, including Moso Bamboo, Arabidopsis thaliana, Oryza sativa L., and Brachypodium distachyon. However, the UBP family within Prunus mume Siebold & Zucc. remains unexplored. In this study, 30 PmUBPs were identified and characterized, all of which contained the UCH conserved domain. They were grouped into 16 subfamilies via evolutionary analysis, revealing similarities in genome structure and motif distribution. PmUBPs were distributed on seven chromosomes and three scaffolds. Gene duplication events, including tandem duplication and segmental duplication, promoted the expansion of PmUBPs. Collinear analysis demonstrated the close relationship between P. armeniaca, P. persica, P. avium, and P. mume. Transcriptome data revealed distinct relative expression trends in PmUBP genes across different tissues. Promoter cis-acting element analysis revealed an abundance of hormone-, light-, and stress-responsive elements across all genes. Transcriptome and reverse transcription quantitative PCR (RT-qPCR) analysis showed that PmUBP2, PmUBP11, PmUBP13, PmUBP18, PmUBP22, and PmUBP26 exhibited relatively high expressions under low-temperature stress. This study provides a theoretical foundation for the role of PmUBP genes in response to low-temperature stress.

Forests doi: 10.3390/f17080894

Authors: Sebastian Mantilla-Valdivia Karla Paliza del Carpio-Banda Andrea Chanove-Manrique Marcelino de la Cruz Berly Cárdenas-Pillco

The high-Andean forests formed by Polylepis rugulosa in southern Peru are key ecosystems for biodiversity conservation and the provision of ecosystem services; however, they are facing fragmentation and degradation processes associated with human activities and climate change. In this context, the present study modeled the near-term and future potential distribution of P. rugulosa under the SSP1-2.6, SSP3-7.0, and SSP5-8.5 shared socioeconomic pathways, considering three analysis periods: 2011–2040, 2041–2070, and 2071–2100. To achieve this, occurrence records, bioclimatic variables, and topographic variables were integrated in BIOMOD2 and complemented with spatial analyses in QGIS. After controlling for multicollinearity using the Variance Inflation Factor (VIF), seven non-redundant environmental predictors were retained and incorporated into an ensemble model built from the four algorithms with the highest predictive performance: Random Forest (RF), Gradient Boosting Machine (GBM), Flexible Discriminant Analysis (FDA) and Artificial Neural Network (ANN). The final ensemble model achieved high predictive accuracy, with True Skill Statistic (TSS) values close to 0.94 and ROC/AUC values ranging from 0.997 to 0.998. Continuous habitat suitability projections were subsequently reclassified into four habitat suitability categories: most unsuitable, marginally unsuitable, marginally suitable, and most suitable. Under the SSP3-7.0 scenario, the most suitable areas decreased from 30,965 ha during 2011–2040 to 374 ha during 2071–2100, indicating a progressive contraction of favorable habitat. A spatiotemporal analysis was then conducted, in which areas of habitat loss, stability, and gain were further disaggregated into specific projected habitat categories: immediate loss, long-term loss, stable niche, expansion and establishment, and delayed expansion. The probability density curves of key environmental variables revealed that stable habitat was mainly associated with mean diurnal temperature ranges of 10.5–11.5 °C, precipitation during the driest quarter of 35–45 mm, slopes of 30–40°, and altitudes of 4000–4500 m a.s.l. Finally, based on the projected habitat trajectories of P. rugulosa, three strategic management typologies were defined: conservation in stable areas, restoration in areas experiencing habitat loss, and preventive conservation and monitoring in areas with future establishment potential.

Forests doi: 10.3390/f17080893

Authors: Jānis Magaznieks Mareks Millers Agris Gabrāns

The quality grading of birch (Betula spp.) veneer logs, an economically important raw material in the Baltic region, is still largely manual, causing pricing inconsistencies, and automated grading under industrial conditions remains rarely studied. We evaluated deep-learning computer vision models for recognising wood defects and assigning a quality class on a sorting line. The algorithm and a scaler evaluated 153 logs using the same images. The recognition differed considerably between the defects: the central core-zone defects were recognised well (recall: core discolouration 97%, pith and drying cracks 91%, core rot 88%), while the dead and rotten knots and the less conspicuous defects were recognised poorly (knots 44%, ingrown bark 52%). The quality class assigned by the algorithm coincided with that of the scaler in 57% of the cases, and the algorithm tended to assign a lower class, mainly because of the over-indication of the core rot. For reference, manual grading itself was not fully repeatable: line scalers agreed with a detailed control scaler in 79% of the cases (69 to 88% between scalers). Automated grading is already accurate for core discolouration and pith and drying cracks, while knot detection remains the main limitation for industrial deployment.

Forests doi: 10.3390/f17080892

Authors: Kongqing Li Yaxuan Cai

Land use change is one of the key factors affecting carbon emissions and environmental quality. Based on current land use data and energy consumption data, this article quantifies carbon emissions from land use in Zhejiang Province from 2005 to 2020, and constructs an economy-population-land-energy-carbon emission coupled system. It analyzes the interactions among land use, population, economic development, energy consumption, and carbon emissions, as well as how these interactions affect the achievement of carbon peaking in Zhejiang Province from a systematic perspective. The results show that (1) During the study period, the rapid urbanization of Zhejiang Province presented significant land conversion characteristics, which are manifested in the expansion of construction land and the reduction of arable land area. (2) From 2005 to 2020, carbon emissions from land use in Zhejiang Province showed an overall upward trend, with a cumulative increase of 5315.074 × 104 tC, and construction land is the main carbon source. (3) According to the current development trend, total carbon emissions in Zhejiang Province will continue to rise. After a comprehensive comparison of five scenarios, rapid population growth and economic development have a certain inhibitory effect on the growth of carbon emissions from land use in Zhejiang Province, while adjusting the land use structure, optimizing the industrial structure, and improving energy use efficiency can effectively reduce carbon emissions from land use.

Forests doi: 10.3390/f17080891

Authors: Jiancheng Zhao Zhenya Yang

Clonal plants generally possess greater growth adaptability under heterogeneous resource environments. Indocalamus latifolius (Keng) McClure has rarely been investigated regarding its clonal integration mechanisms and morphological plasticity under heterogeneous nitrogen (N) conditions. In this study, I. latifolius were exposed to different N distribution regimes with either connected or severed ramets. Biomass, root morphological, non-structural carbohydrate, and N were determined to investigate how clonal integration and root morphological plasticity enable I. latifolius to respond to heterogeneous N availability. Results revealed that compared with uniform N addition, the two localized N treatments promoted biomass accumulation of ramets in high-N patches, and localized N addition to daughter ramets was more beneficial to biomass accumulation of the clonal system. Clonal integration achieved through rhizome connection promoted growth and N accumulation in daughter ramets, increased root length and root soluble sugar content of ramets in low-N patches and reduced average root diameter. Overall, resource allocation was prioritized to daughter ramets and high-N patches; clonal integration drove compensatory root proliferation and morphological adjustment for ramets in low-N patches. This study advances the understanding of adaptive strategies adopted by clonal plants in heterogeneous habitats and lays a theoretical foundation for precision nutrient management of I. latifolius.

Forests doi: 10.3390/f17080890

Authors: Yupu Li Chuanmei Zhu Yihang Xiang Minglu Sun Xiangyu Ge Shipeng Nie Zipeng Zhang

Urban expansion has profoundly altered ecosystem carbon dynamics, yet its associations with changes in aboveground biomass (AGB) and belowground biomass (BGB) remain insufficiently understood at the national scale. This study investigated urban expansion areas in 352 Chinese cities from 2000 to 2020 using 1-km-resolution AGB and BGB datasets. By integrating temperature, precipitation, potential evapotranspiration, and atmospheric CO2 concentration, we developed the Enhanced Aboveground Biomass Deviation Index (EAGB) and Enhanced Belowground Biomass Deviation Index (EBGB) to identify areas showing positive and negative biomass responses during urban expansion and to explore their spatial patterns and driving mechanisms. Between 2000 and 2020, China’s urban land expanded by 52,635 km2, corresponding to an average annual expansion rate of 4.1%. Areas showing positive biomass responses during urban expansion accounted for 22,376 km2 (42.5%) for AGB and 23,569 km2 (44.8%) for BGB, mainly concentrated in East and Central China. In contrast, areas showing negative biomass responses covered 5233 km2 (9.9%) for AGB and 3911 km2 (7.4%) for BGB, primarily distributed in Northwest and Southwest China. During urban expansion, biomass declines were more frequently observed in rapidly expanding small- and medium-sized cities in Northwest and North China, whereas larger cities generally exhibited more widespread biomass gains. Climatic factors, particularly precipitation and atmospheric CO2 concentration, together with human activities, were the dominant drivers of the observed spatial heterogeneity. Moreover, the dominant driving mechanisms shifted from the combined influence of climatic factors and human activities during 2000–2010 to the combined influence of climatic and topographic factors during 2010–2020. These findings provide a new framework for assessing biomass responses during urban expansion and offer scientific support for urban land-use optimization and ecological conservation.

Forests doi: 10.3390/f17080889

Authors: Xuemin Huang Xingbin Xu Jing Che Guoyan Zeng Yexin Lv Jiaorong Qian Mao Ye

To elucidate the response characteristics of radial growth and water use strategies in coniferous forests of cold-arid regions to drought stress, this study focused on Larix sibirica in different forestry areas of the Altai Mountains. Using dendrochronology and stable isotope techniques, we calculated the basal area increment (BAI) and intrinsic water-use efficiency (iWUE), and combined these with the standardized precipitation–evapotranspiration index (SPEI) to identify drought events, to investigate tree growth and water-use efficiency responses to climate variability. The results showed that drought years were characterized by reduced radial growth and increased iWUE in Larix sibirica across both forest regions, and tree-ring-derived intercellular CO2 concentration (Ci) increased with rising atmospheric CO2 concentrations, whereas the Ci/Ca ratio remained relatively stable throughout the study period. Scenario analysis revealed that, prior to 1980, the long-term trend in iWUE was more consistent with the constant Ci scenario, suggesting relatively strong stomatal regulation. After 1980, iWUE trends became more closely aligned with the constant Ci/Ca scenario, indicating that trees maintained a relatively stable Ci/Ca ratio to balance carbon assimilation and water loss. With increasing drought severity, drought resistance declined in both forest regions; however, substantial spatial differences were observed in drought responses. Under moderate drought conditions, trees in the Haba-River forest area exhibited higher resistance, whereas trees in the Hanaslin forest area showed greater recovery capacity and ecological resilience. Winter temperature, growing-season temperature, late-season temperature, and water availability were identified as key climatic factors influencing variations in the radial growth and iWUE of Larix sibirica. Overall, under the combined influences of rising atmospheric CO2 concentrations and increasing water limitations, Larix sibirica exhibited adaptive adjustments in carbon–water regulation; however, enhanced iWUE did not fully compensate for the negative effects of drought on radial growth. These findings provide valuable insights into the responses and adaptive strategies of cold-arid forest ecosystems under ongoing climate change and offer scientific support for the conservation and sustainable management of Larix sibiric forests.

Forests doi: 10.3390/f17080888

Authors: Tomaž Adamič Jurij Diaci Gal Fidej Dušan Roženbergar

Close-to-nature silviculture, based on natural regeneration, provides a suitable framework for the use of wildlings (naturally regenerated seedlings), enabling their direct collection and transplantation. Wildlings are a promising tool for small-scale forestry, difficult terrain, post-disturbance restoration and assisted range expansion, although their establishment success remains insufficiently understood under varying site and physiological conditions. This study evaluated survival and temporal dynamics of vitality of wildlings of Norway spruce, silver fir, and European beech planted in six experimental forest gaps in a temperate Alpine forest (Pohorje Mountains, Slovenia). A total of 162 wildlings were monitored across 12 repeated assessments between 2018 and 2025, combining data on survival, vitality, morphology and environmental conditions. Survival differed strongly among species, with Norway spruce showing the highest survival (59.3%), followed by European beech (50.0%), while silver fir showed markedly lower survival (20.4%). Initial vitality emerged as the primary determinant of survival, whereas the influence of morphological traits was species-specific. Longitudinal analyses revealed contrasting vitality trajectories among species. Norway spruce exhibited a gradual decline consistent with cumulative stress effects, silver fir showed a strongly non-linear, threshold-like decline, and European beech demonstrated improving vitality over time, indicating progressive acclimation to local conditions. Structural traits such as crown development and root collar diameter were important predictors in Norway spruce, growth performance was dominant predictor in silver fir, and crown-related traits were most important in European beech. Models based on truncated trajectories improved model fit while maintaining consistent results, supporting the robustness of these patterns. The results indicate that early establishment acts as a critical filtering stage and suggest that differences in initial wildling quality, phenological status at planting, and biotic stress may contribute to variation in survival among species. In particular, the low survival of silver fir may partly reflect phenological differences associated with elevational transfer. These findings suggest that successful application of wildlings in assisted range expansion and climate-adaptive forest management requires not only appropriate species selection but also careful consideration of seedling quality, planting phenology, and microsite conditions.

Forests doi: 10.3390/f17080887

Authors: Hong-Sik Ju Jae-Heun Oh Ho-Seong Mun Sang-Kyun Han

Small harvesting compartments and steep terrain in South Korea favor harvesting systems in which a single machine performs multiple processes. Multifunctional systems based on small tracked excavators, equipped with a grapple saw for felling and a clambunk skidder for extraction, have therefore been increasingly adopted to address labor shortages and to improve operational safety. However, because these base machines lack a chassis suspension system and their operator seats provide limited vibration isolation, operators of small-excavator-based systems may be exposed to elevated levels of whole-body vibration (WBV) and shock vibration. This study quantified operator ride-vibration exposure and assessed the associated health risks during small-excavator-based timber harvesting in accordance with ISO 2631-1; the assessment was based on measured vibration exposure rather than on direct medical evaluation. Tri-axial accelerations were measured simultaneously at the operator seat and the cab floor of a 5-ton-class excavator over eight workdays, and one representative workday was analyzed at the work-element level. The harvesting process was divided into timber felling (machine travel, positioning, clearing, and cutting and bunching) and timber extraction (machine travel on forest roads, machine travel on skid trails, and loading and unloading). Exposure was evaluated using the frequency-weighted root-mean-square (RMS) acceleration, the crest factor (CF), and the total vibration dose value (TVDV). The CF exceeded 9 for all work elements, indicating shock-dominated vibration and justifying the TVDV as the primary evaluation metric. Timber extraction generated higher vibration exposure than timber felling, and the seat TVDV differed significantly among the work elements within each operation (p < 0.001). The highest seat TVDV occurred during loading and unloading (123.05 m/s1.75), exceeding the upper ISO 2631-1 Health Guidance Caution Zone limit for an 8-h exposure by more than eight times, and all major work elements exceeded the ISO 2631-1 health guidance limits. To our knowledge, this study provides the first work-element-level quantification of WBV exposure for small-excavator-based timber harvesting systems in South Korea. The findings underscore the need for improved seat suspension systems, vibration mitigation technologies, and vibration-aware work planning strategies.

Forests doi: 10.3390/f17080886

Authors: Namrata Bhusal Susete Marques Srijana Poudel Palaiologos Palaiologou Olga Roussou Kostas Kalabokidis José G. Borges

Forest landscape configurations in Mediterranean regions often promote fuel continuity, low structural heterogeneity, and inefficient spatial allocation of fuel treatments, increasing wildfire intensity and spread. This study improves wildfire risk management by applying spatially explicit Integer Linear Programming (ILP) models to optimize fuel-treatment allocation under operational constraints in two Mediterranean case studies: Vale do Sousa, Portugal, and Lesvos Island, Greece. In Portugal, wildfire risk was represented using a stand-level wildfire resistance indicator that accounts for the spatial influence of neighboring stands, whereas in Greece, simulation-derived fire spread probabilities from the FSim fire behavior model were used to prioritize high-risk treatment zones. Despite differences in modelling complexity and data availability, both optimization frameworks generated spatially targeted treatment strategies under contrasting wildfire risk representations. Optimized treatment allocation increased landscape-level wildfire resistance in Portugal from 0.9907 to 0.9959 and reduced expected wildfire risk in Greece from 0.1751 to 0.1701 across increasing treatment-area scenarios. Although these improvements were modest in magnitude, they were consistent across all scenarios. The novelty of this study lies in demonstrating the transferability of an ILP-based optimization framework across contrasting Mediterranean contexts, providing a practical decision-support tool for prioritizing fuel treatments and supporting adaptive, risk-informed forest management.

Forests doi: 10.3390/f17080885

Authors: Felipa De Jesús Rodríguez-Flores Marín Pompa-García

Tree-ring chronologies are essential proxies for investigating ecosystem dynamics and reconstructing environmental variability, yet integrative approaches for assessing chronology quality and sampling representativeness across heterogeneous regions remain limited. We analyzed 190 tree-ring chronologies distributed across Mexico and developed two composite indicators: the Signal Quality Index (SQI), integrating internal coherence, interannual sensitivity, common growth signal strength, and the Sampling Representativeness Index (SRI), quantifying the statistical adequacy of sampling efforts. Both indices were standardized and evaluated using Moran’s I, Local Indicators of Spatial Association (LISA), Getis–Ord Gi* hotspot analysis, and correlations with climatic, hydrological, and edaphic variables. Results revealed a marked decoupling between chronology signal quality and sampling representativeness. SQI exhibited significant positive spatial autocorrelation, with clusters of high and low values associated with hydroclimatic gradients. It was strongly related to indicators of water availability and atmospheric evaporative demand, suggesting greater growth coherence under water-limited conditions. In contrast, SRI displayed weak spatial structure and largely non-significant relationships with environmental variables, indicating that representativeness is driven primarily by methodological decisions and sampling design. These findings highlight complementary ecological (SQI) and methodological (SRI) dimensions of dendrochronological networks and provide a practical framework for improving chronology evaluation, comparability, and network development across environmentally heterogeneous regions.

Forests doi: 10.3390/f17080884

Authors: Shahla Ghaffari Jabbari Jose Fermoso Domínguez Sandra Rodríguez Sufuentes Svein Olav Nyberg Tore Sandnes Vehus Henrik Kofoed Nielsen

Selecting interior wood materials requires balancing functional and aesthetic demands with indoor air quality, as wood can emit volatile organic compounds (VOCs) and very volatile organic compounds (VVOCs) that either peak shortly after installation or persist over time. This study investigated time-resolved VOC and VVOC accumulation concentrations from untreated pine, spruce, aspen, and oak, representing wood species commonly used in Norway. Concentrations of VOCs and VVOCs were monitored for 25–28 days under low-ventilation, worst-case chamber conditions using Proton Transfer Reaction–Time-of-Flight Mass Spectrometry (PTR-TOF-MS). Emission behaviour was assessed using peak concentration, decay rate, half-time, stabilised concentration, cumulative exposure (AUC28), and available health-based thresholds. Clear species-dependent differences were observed. Pine was the dominant VOC source, with the highest peak concentration, stabilised concentration, and AUC28, mainly due to monoterpenes, which remained above the health-based threshold throughout the test period. Oak showed the second-highest VOC burden and a distinct acetate-dominated profile, with acetic acid showing the longest predicted exceedance duration. Aspen and spruce had lower VOC burdens, but their cumulative VVOC exposure exceeded VOC exposure. VVOCs generally peaked earlier than VOCs, although persistence varied by species. Overall, the concentration of VOCs and VVOCs was controlled by species, compound chemistry, volatility, and internal transport, supporting species- and compound-specific ventilation and material-selection strategies.

Forests doi: 10.3390/f17080882

Authors: Dongdong Wang Xinxin Shi Ruihan Yang Guangxing Liu

Effective characterization of water and their relationship is the current focus and difficulty of grassland soil and water loss research. This investigation utilized simulated rainfall to conduct experiments. The findings revealed the following: ① The sediment yield of grassland under different slopes decreases linearly with the increase in water yield. The sediment yield of grassland under different rainfall intensities increases linearly with the increase in water yield. The decrease is more obvious between 30% and 40%, and 60% and 70%, coverage. ② This phenomenon may be attributed to the stronger correlation between plant biomass and sediment yield compared to that between plant biomass and water yield. The efficacy of vegetation coverage in characterizing grassland sediment yield surpasses its ability to depict water yield. ③ The variability of is more obvious than that of, and the relationship between and has cyclical characteristics. ④ This study uses volume and root dry weight to establish an empirical equation for the relationship between sediment yield and water yield. Later studies should supplement field experiments and determine the main controlling factors and the conduction paths between factors. The research will provide technical guidance for grassland water and soil resource management and soil erosion model optimization.

Forests doi: 10.3390/f17080883

Authors: Jakub Medek Ján Holécy Blanka Giertliová Michaela Korená Hillayová Maroš Sedliak

Standard actuarial methods often fail to accurately price the risk of catastrophic events due to the characteristic low frequency and high severity of such occurrences. To address these limitations, two actuarial solutions that integrate current knowledge of extreme value theory (EVT) with the theory of non-life insurance are proposed. To address the extreme risk, the Gumbel distribution (solution E1) and the chi-squared distribution (solution E2) were applied. The applicability of the proposed insurance models against the risk of windthrow damage was demonstrated on Norway spruce (Picea abies L. Karst.) stands at a national scale within the Slovak Republic. The results reveal a crucial economic relationship between the insurance layers: the higher the reliability and cost of coverage in the primary model, the cheaper the subsequent secondary premium for risk of extreme damage becomes. For both assumed return periods of 20-year and 100-year extreme events, the solution E2 generates lower and more acceptable total insurance premiums. Subsequently, both models address effectively the foundational insurance concept of risk minimization through spatial diversification.

Forests doi: 10.3390/f17080881

Authors: Joanna Budnicka-Kosior Agnieszka Czajka Anna Mazur Krystyna Kurowska

Contemporary urbanization, particularly in the suburban zones of major cities, intensifies conflicts at the interface between forested and developed areas. Forests, as critical components of municipal functional and spatial structures, face increasing development pressure, primarily driven by escalating social demands for housing. This study evaluates the effectiveness of spatial policy implementation in safeguarding and maintaining forested areas, taking into account their distinct environmental and functional characteristics. The research focuses on selected municipalities near Warsaw: Izabelin, Jabłonna, Wiązowna, Lesznowola, and Podkowa Leśna, all of which experience significant investment pressure and possess a high proportion of forest cover. The analysis utilizes qualitative and comparative research methods. A Forest Planning Protection Quality Index (FPPQI) was developed through expert-based assessment of local spatial development plans to evaluate the quality of planning solutions for forest protection. The results were compared with the degree of forest fragmentation identified through GIS analyses. The expert method was used to evaluate selected local plans for the quality of planning protection of forest areas. Additionally, spatial analyses in a GIS environment assessed whether municipalities with a low FPPQI, resulting from ongoing suburbanization, also exhibit increasing forest fragmentation. The findings demonstrate that forest protection effectiveness is determined primarily by the quality of planning provisions in local spatial development plans, rather than by the extent of planning coverage. Municipalities experiencing high suburbanization pressure and lower FPPQI values exhibited increased forest fragmentation, while those with more restrictive planning regulations preserved greater spatial continuity of forest complexes.

Forests doi: 10.3390/f17080880

Authors: Yayan Zhu Qinmeng Zeng Feng Xiao Xueyan Jian Fang Li Jiajuan Xu Yingying Wei Hui Li Jie Xu

Camellia oleifera is a significant woody oil tree species native solely to China. The bud–seedling grafting technique has been widely applied to this tree due to its significant advantages in improving propagation efficiency and shortening the growth cycle. However, the healing process and its underlying molecular regulatory mechanisms during interspecific heterografting in Camellia remain poorly understood. In this study, we established both homografting and heterografting systems using C. oleifera bud seedlings as rootstocks, grafted with scions from C. oleifera, C. meiocarpa, and C. weiningensis. We systematically investigated the response patterns and differences in metabolites and gene expression before and after grafting healing through endogenous hormone detection, LC-MS untargeted metabolomics, and transcriptomic sequencing. The results showed that the grafting survival rates between C. oleifera and the other species were high (>88%), indicating strong compatibility. Metabolomic analysis revealed that differential metabolites, such as Gibberellin A53, Sophoramine, and Morellin, accumulated significantly with prolonged grafting time, and interspecific grafting combinations exhibited specific highly expressed metabolite profiles. We integrated multi-dimensional data comprising hormone levels, differential metabolites, and DEGs. A “hormone-gene” interaction network was constructed using WGCNA. The analysis revealed that key hub genes, including CYP73A, F3H, CHS, LHCA1, and LHCB5, were significantly correlated with flavonoid biosynthesis and elevated iPR content. We hypothesize that these genes enhance graft healing capacity by regulating secondary metabolism and hormone signaling pathways. The identified candidate genes, phytohormones, and metabolites provide potential molecular markers and regulatory targets for evaluating graft compatibility, selecting suitable rootstock–scion combinations, and optimizing grafting and propagation practices in C. oleifera, providing a crucial theoretical basis for superior cultivar breeding and the investigation of graft compatibility mechanisms.

Forests doi: 10.3390/f17080879

Authors: Yonghua Liu Qi Zhang Dazhao Liu

Under the combined impacts of climate change and intensified human activities in coastal zones, mangrove ecosystems are increasingly exposed to degradation, fragmentation, and declines in ecological functions. It is therefore important to systematically examine the progress and evolution of the research hotspots in remote sensing monitoring of mangroves. In this study, 942 publications on mangrove remote sensing monitoring from 2000 to 2025 were retrieved from the China National Knowledge Infrastructure (CNKI) and the Web of Science Core Collection, comprising 485 CNKI records and 457 Web of Science records. CiteSpace 6.4.R2 was used to conduct bibliometric and knowledge-mapping analyses of publication trends, geographic distribution, author collaboration networks, keyword co-occurrence, keyword cluster timelines, and burst keywords. The results show that research on mangrove remote sensing monitoring generally increased over time, with marked growth after 2015. Research topics gradually shifted from early studies on mangrove distribution mapping, land-use change, and image classification to multi-source remote sensing applications, change detection, biomass estimation, blue carbon assessment, and machine learning- and deep learning-based methods. Author collaboration networks provide a descriptive overview of collaboration patterns and suggest that cross-team and cross-regional collaboration still needs to be strengthened. Keyword co-occurrence, cluster timeline, and burst keyword results indicate that remote sensing monitoring, machine learning, deep learning, random forest, support vector machine, object-based image analysis, ALOS PALSAR, ALOS-2 PALSAR-2, blue carbon, carbon stock, aboveground biomass, ecosystem services, and forest degradation are important themes in this field. Future research should further strengthen multi-source remote sensing data integration, cross-regional validation of intelligent algorithms, degradation monitoring indicator systems, uncertainty assessment, and long-term time-series analysis. These efforts will improve the accuracy, comparability, and management applicability of mangrove remote sensing monitoring and provide scientific support for coastal ecological conservation, mangrove restoration, and blue carbon governance.

Forests doi: 10.3390/f17080877

Authors: Jia-Hui Meng Wen-Teng Zuo Lei Rao Kang-Ping Liao Hong-Chao Liu Liu-Qiang Wang Ting-Ting Sun

Salt stress significantly constrains plant growth and development, with the root system serving as the primary organ for sensing and responding to salinity. Poplar (Populus spp.), a widely cultivated tree species, plays important roles in urban greening, windbreaks and sand fixation, and various economic sectors. In this study, we conducted a comparative analysis of the salt tolerance of root systems of six different poplar cultivars. Key physiological indicators—including root activity, ion homeostasis, reactive oxygen species (ROS)-scavenging capacity, and nitric oxide (NO) content—were evaluated under saline conditions. Our findings indicate that the salt resistance of the six cultivars follows the order: P. simonii > P. cathayana > P. tremula × P. alba ‘717’ > P. deltoides × P. euramericana ‘Nanlin 895’ > P. deltoides × P. euramericana ‘Bofeng 3’ > P. alba × P. glandulosa ‘84K’. Furthermore, a transcriptomic analysis was performed on the most resilient species, P. simonii. These results reveal that P. simonii primarily orchestrates its salt stress response through the modulation of MAPK cascades and nitrogen metabolism pathways. This research provides theoretical support for elucidating the molecular mechanisms underlying the salt stress response in poplars and offers a foundation for the molecular breeding of salt tolerant poplar varieties.

Forests doi: 10.3390/f17080878

Authors: Logan Wimme Mark Corrao Dan Kluskiewicz Joel Glaze

This study investigated the influence of airborne laser scanning (ALS) pulse density on the accuracy of total tree height estimates and the quality of raster products commonly used in individual tree detection (ITD) workflows. Using a high-density (36 pulses per square meter (PPM)) ALS dataset, we generated lower-density subsets and compared derived outputs using a standardized processing pipeline. Tree height estimates were validated against field measurements, and elevation products—digital elevation models (DEMs), digital surface models (DSMs), and canopy height models (CHMs)—were assessed across pulse densities. DSM and CHM quality improved with increasing density, showing reduced bias and tighter variation. In contrast, DEM accuracy remained relatively stable across densities, indicating lower-density ALS may suffice for ground modeling in forested environments. The results also revealed a strong positive relationship between pulse density and total tree height accuracy. Higher-density datasets consistently produced more accurate and less biased tree height estimates, while sparser datasets exhibited systematic underestimation due to missed canopy peaks. These findings emphasize the importance of aligning ALS pulse density with project objectives. While low-density data may be adequate for terrain modeling, higher-density acquisitions are critical for reliable canopy representation and accurate ITD outputs. This study provides operational guidance for forestry practitioners and highlights the value of investing in higher-resolution ALS data for modern forest inventories.

Forests doi: 10.3390/f17080876

Authors: Francisco Balocchi Alberto Paredes Hardin Palacios Andrés Iroumé

Disentangling the effects of climate variability and forest management on catchment hydrology remains a major challenge in temperate plantation landscapes. We analyzed 21 hydrological years (1997/98–2017/18) of precipitation and runoff records from two experimental catchments in the Chilean Coastal Range with contrasting silvicultural histories to characterize changes in low-flow behavior. Hydroclimatic and low-flow indices were evaluated using the monotonic trends test, Sen’s slope estimates, change point detection, and standardized inter-catchment anomaly differences. Annual and seasonal precipitation indices, rainfall frequency, and maximum dry-spell duration showed no significant monotonic trends, whereas maximum 5-day precipitation declined at LP. The two catchments nevertheless exhibited divergent low-flow trajectories. Los Pinos, managed through partial harvesting and thinning within a forest mosaic, showed decreasing normalized low-flow availability and longer low-flow exposure during the latter part of the record. La Reina, clearcut in 1999/2000 and subsequently reforested, showed a progressive increase in low-flow magnitude and normalized low-flow availability, together with declining flow variability and fewer below-threshold events. Standardized inter-catchment comparisons confirmed a temporal divergence in low-flow behavior. They also revealed a concurrent shift in inter-catchment precipitation anomalies. These results indicate contrasting long-term hydrological trajectories that are consistent with differences in forest management histories; however, the non-paired study design, limited pre-harvest observations at La Reina, and differential precipitation forcing preclude formal attribution to silvicultural effects alone. This study highlights the value of long-term experimental catchments for evaluating low-flow dynamics under interacting climatic and land-management influences.

Forests doi: 10.3390/f17080875

Authors: Changhao Xie Yuning Jia Jingran Yang Baohui Zhao Yang Zhang Chengliang Wu

Based on survey data from 579 farmer households in major non-timber forest product (NTFP) regions of Zhejiang Province, this study comprehensively employs binary logit/ordered probit and machine learning methods for cross-validation. It systematically examines the effects of multiple factors, including perceived property rights security, technical training, village rules and regulations, ecological awareness, and economic incentives, on forest farmers’ adoption of green production technologies. The cross-validation between econometric and machine learning approaches enhances the reliability of the findings. Results show that perceived property rights security is robustly and positively associated with green production behavior, while village rules and regulations and ecological awareness emerge as the two most critical driving factors. These associations exhibit significant NTFP-type heterogeneity: the impacts of technical training and forestry subsidies vary in direction depending on the crop cultivated, rendering traditional one-size-fits-all policies ineffective. This study highlights the crucial role of informal institutions and environmental awareness in the green transition, offering empirical evidence for designing differentiated training programs, optimizing penalty gradients, and implementing targeted subsidy policies.

Forests doi: 10.3390/f17080874

Authors: Jun Wu Shuo Liu Xiaojin Huang Yuqiao Zhang Xiaokuo Qin Wenzhe Zhu Ran Cheng

Against the backdrop of stock-space urban renewal, green-space governance in megacity cores increasingly requires a shift from expansion-oriented supply to the optimisation of existing spatial resources. This study examines the spatial equity of green-space provision in the central districts of seven Chinese megacities using high-resolution remote-sensing data from 2015, 2020, and 2025. We combined semantic segmentation, nested-buffer measurement, the Gini coefficient, Extreme Gradient Boosting (XGBoost), and Shapley Additive Explanations (SHAP) to evaluate the relationships between urban morphology and green-space provision. We first derived a pixel-level cumulative green-space provision index from nested-buffer measurements and calculated city-year Gini coefficients to quantify distributional inequality. XGBoost models were then used to predict the cumulative green-space provision index from urban morphology, and SHAP was applied to interpret the resulting nonlinear, model-derived associations. The results show that changes in the green-space provision index and its distributional inequality were not synchronous across cities. Beijing showed the largest increase in inequality, whereas Chengdu showed the strongest improvement; Tianjin recorded the fastest increase in the green-space provision index, while Beijing experienced a marked decline. Urban form showed nonlinear associations with the unit-level green-space provision index, helping to explain the spatial differentiation underlying the city-year Gini coefficients. Building density was the primary contributor in most city-year models, whereas compactness showed threshold-like associations, with positive effects at lower levels and inhibitory effects at higher levels. Statistical testing and clustering further indicated substantial heterogeneity among cities, which were categorised into three spatial patterns: centripetal agglomeration, peripheral expansion, and clustering/ring-shaped fluctuation. These findings provide morphology-based evidence for differentiated green-space governance in high-density megacity cores, though they should not be interpreted as a complete socioeconomic assessment of green-space equity.

Forests doi: 10.3390/f17080873

Authors: Jehoshua Macedo-Bedoya Fernando Camones Gonzalez Abel Salinas-Inga Enoc Jara-Peña José Campos de la Cruz Bruno Padilla-Torres Geancarlo Alarcon-Iman Doris Gómez-Ticerán Sergio Olórtegui-Chamoli Eliana Quispitupac Olga Lidia Solano Dávila Yakov Quinteros-Gómez

Tropical rocky outcrops are considered biological islands with high endemism and challenging environmental conditions. Ant gardens (AGs) represent a sophisticated ant–plant mutualism that may facilitate plant establishment in these restrictive habitats. This study conducted a comprehensive floristic inventory of Morro de Calzada (MdC), a tropical rocky outcrop in the Peruvian Andean–Amazonian piedmont, and evaluated the relationship between plant composition and the presence of AGs across six sampling units (912–1413 m a.s.l.). A total of 310 vascular plant species (77 families, 180 genera) were recorded. Melastomataceae (37 spp.), Moraceae (18 spp.), and Rubiaceae (18 spp.) were the most diverse families. Species richness decreased with elevation, with sampling unit 2 (951–1050 m a.s.l.) showing the highest richness (170 spp.) and sampling unit 6 the lowest (52 spp.). AGs were concentrated in the sampling unit SU4, which hosted the highest phorophyte richness (12 spp.) and number of gardens (22); this diversity was possibly driven by canopy and host-tree structure. The ant Azteca trailii tococae was the primary builder, showing strong associations with Meriania aff. microflora and Ficus citrifolia. Epiphyte composition was dominated by Anthurium gracile, with Epiphyllum phyllanthus as a notable xerophytic element. AG dimensions correlated positively with host-tree DBH and height. High floristic turnover among sampling units (Jaccard dissimilarity 0.78–0.94) contrasted with structural homogeneity of gardens, indicating ecological plasticity of Azteca trailii. The study highlights the role of AGs as ecosystem engineers in rocky outcrops and emphasizes the conservation value of MdC, which harbors endemic and threatened species. Sampling unit SU4 emerges as a functional hotspot for ant–plant mutualisms.

Forests doi: 10.3390/f17080872

Authors: Yuebin Lin Yan Ke Xiang Ji Shulin Chen Shuangjiao Cai

Urban forest walkways provide accessible forest recreation opportunities within cities, but little is known about how different walkway landscape environments are associated with older adults’ perceived psychological restoration. This study examined three representative urban forest walkways in Fuzhou, China, by integrating image-based landscape classification with photo-elicitation questionnaires. A total of 1188 field photographs were collected, of which 963 valid images were used for landscape analysis. A SegNet-based semantic segmentation model was used to extract major landscape elements, and the images were subsequently classified into four landscape environment types. Questionnaire data were obtained from 415 older walkway users, generating 4980 respondent–image evaluation records. The SegNet model achieved a mean IoU of 79.4%. The high-naturalness canopy-immersive type received the highest scores for tranquillity, refuge, naturalness, landscape preference, and perceived psychological restoration, whereas the semi-open viewing-platform type showed the highest spaciousness and prospect scores. Landscape preference was positively associated with perceived psychological restoration in the mixed-effects model and partially mediated the associations between selected perceived landscape attributes and perceived psychological restoration. These findings suggest that age-friendly urban forest walkway design should maintain canopy immersion, provide semi-open viewing nodes, improve resting and interaction spaces, and refine forest-edge urban-interface sections.

Forests doi: 10.3390/f17080871

Authors: Hamid R. Taghiyari Elham Nadali Antonio Pizzi Roya Majidi Mohammad Taheri Mohammad Hassan Sowlat Olaf Schmidt Antonios N. Papadopoulos

Fungal decay poses a significant threat and causes substantial economic losses worldwide. Graphene is a nanomaterial with positive results in improving paints and finishes, eventually protecting the substrates from damages, including fire and wood-decay fungi. This study investigated the effectiveness of graphene in an acrylic paint to protect unheated and thermally modified wood substrates from Trametes versicolor. Three commercial wood species were coated with either plain or graphene-enriched paints; a separate set of specimens was prepared for thermal modification at 185 °C. Exposure to T. versicolor was carried out for four months, and the impact of fungal degradation was evaluated through mass loss and a mechanical property. Incorporation of graphene markedly reduced mass loss in both unheated and thermally modified specimens; it also improved the compression strength compared with the controls, demonstrating its dual protective and reinforcing effects. These results highlighted the potential of graphene as an efficient and practical additive in acrylic paints, offering a viable and easy-to-apply method for protection of hardwood and softwood substrates against fungal biodeterioration.

Forests doi: 10.3390/f17080870

Authors: Yanan Rong He Shao Yu Shi Mengqi Liu Changyi Liu

Bamboo is a natural fiber-reinforced composite whose macroscopic mechanical properties depend on the microscale synergistic deformation of fibers and parenchyma. However, existing in situ SEM testing techniques are mainly designed for metallic tensile testing and are unsuitable for analyzing bamboo’s meso-scale behavior. To address this, we developed an in situ SEM three-point bending instrument specifically for natural fiber materials. The instrument keeps the region of interest (ROI) stably centered in the SEM field of view through a stationary central indenter and symmetrically moving supports. It offers a 0–450 N load range, 0.5N force resolution, 1 μm displacement resolution, and is compatible with a Tescan Vega 4 SEM chamber. Using this instrument, in situ bending tests were performed on Moso bamboo (Phyllostachys edulis) with fiber volume fractions of 23%–42%, combined with digital image correlation for full-field strain measurement. Results show that flexural modulus, strength, and fracture work all increase significantly with fiber content. A microstructural failure classification framework was established based on in situ SEM observations, categorizing the observed failure modes according to the local arrangement of fibers and parenchyma. The proportions of these failure modes were found to be closely associated with the gradient distribution of strength and toughness across the culm wall. Three extrinsic toughening mechanisms were identified: fiber-induced crack deflection, parenchyma cell collapse densification, and fiber–parenchyma interfacial debonding. The developed instrument and analysis method offer a promising experimental platform for multi-scale mechanical characterization of natural composites.

Forests doi: 10.3390/f17080869

Authors: Hua Zhu Qing Zhang Ligang Xu Ming Tang Ying Liu Xingyuan Wu

Accurate modeling and partitioning of forest evapotranspiration (ET) are essential for understanding water cycle processes in forest ecosystems. This study develops an improved three-source ET model by integrating a physically based canopy interception evaporation (Ei) scheme into the Shuttleworth–Wallace–Hu (SWH) model. A Monte Carlo stochastic parameterization scheme was applied to optimize model parameters. The proposed framework disaggregates the total ET flux into three distinct components: vegetation transpiration, soil evaporation, and Ei, thereby reducing uncertainties associated with the original SWH model in humid forest regions. The new model’s performance was assessed using flux observations from two subtropical forest sites and compared to the SWH model. The verification results indicate that the three-source model provided reliable estimates of daily ET. At the QYZ station (2004–2007) and the DHS station (2005–2007), the fitting slopes for simulating daily ET were 0.97 and 1.01, respectively, with corresponding coefficients of determination of 0.92 and 0.81. The root mean square errors (RMSE) for the three-source model were 0.38 mm day−1 and 0.52 mm day−1, respectively, with a reduction of 4.33% and 3.10% in RMSE compared to the SWH model. Additionally, the new model simulated the annual T/ET ratio more accurately, with values closer to site-measured data than the SWH model’s estimates. At both sites, the T/ET ratios simulated by the new model were closer to the observed values than those simulated by the SWH model, indicating an improved representation of ecohydrological processes. Furthermore, environmental analysis revealed that vapor pressure deficit and precipitation primarily govern the T/ET ratio, exerting the strongest positive and negative effects, respectively. Importantly, it requires only one additional precipitation parameter compared to the SWH model, yet achieves higher simulation accuracy and a more realistic representation of hydrological processes. Overall, the three-source model provides an improved framework for estimating ET in humid forest ecosystems. Ultimately, these results offer deeper insights into the coupled water and energy fluxes within forest ecosystems, thereby facilitating more effective water management and guiding sustainable forestry under a shifting climate.

Forests doi: 10.3390/f17080868

Authors: Jialin Yue Feng Liu Gui Zhang Zhigao Yang Menyuan Zeng

Climatic drought shapes wildfire regimes, yet the multi-timescale lagged responses of high-intensity wildfires to drought and their spatial heterogeneity remain unclear in subtropical monsoon forests. We integrated long-term MODIS satellite observations and monthly drought metrics (SPEI, VPD, VAP, and precipitation) across subtropical China during 2005–2024. We used Spearman rank correlation to identify multi-scale drought–wildfire relationships and constructed zero-inflated negative binomial generalized linear mixed models (ZINB-GLMM) to quantify multi-temporal drought, vegetation, and anthropogenic effects. Our results showed that 64.7% of 0.5° grid cells experienced high-intensity wildfires, with 77.8% of events occurring in the cold dry season (November–March). Concurrent dry conditions (low SPEI, VAP, precipitation) generally increased fire susceptibility, while atmospheric aridity (high VPD) showed spatially dipolar effects. The 1–3-month lagged model had the highest explanatory power (R2 = 0.54), identifying antecedent moisture deficit as the dominant driver. Dense vegetation amplified drought–fire synergies, especially in southeastern and southwestern China. Model predictive performance was strong overall, but lower accuracy in northern areas suggests additional local factors modulate wildfire risk there. This study provides a satellite-based spatiotemporal modeling framework that may serve as a methodological reference for ecological informatics-based wildfire early warning and climate-adaptive management in subtropical and analogous monsoon regions.

Forests doi: 10.3390/f17080867

Authors: Qiaorui Ba Ling Nan Baokang Liu

This study develops a workflow for forest carbon accounting in the West Qinling Mountains, China (2000–2025), integrating CLCD data, key-year forest subtype mapping, and InVEST-style carbon pools. Forest subtypes were classified with Random Forest under spatial block cross-validation (overall accuracy = 59.76%, Cohen’s Kappa = 0.3974, Macro-F1 = 0.5944). Under the baseline workflow, total carbon stock increased from 876.40 to 954.45 million Mg C, yielding a net gain of 78.05 million Mg C (+8.91%). The Hamed–Rao modified Mann–Kendall test identified a significant increase (Sen’s slope = 2.41 million Mg C year−1, p=2.99×10−5). A bounded parameter sensitivity analysis produced a 2025 total carbon range of 887.07–1021.84 million Mg C, whereas Scheme A yielded a more conservative net gain of 60.19 million Mg C. County-level patterns were broadly similar across scenarios, but fine-grained ranking remained uncertain. Because the annual series is a hybrid product, with annual forest/non-forest updates but a subtype structure refreshed only at key years, the results should not be interpreted as an independently reconstructed annual record of subtype transitions. The workflow therefore provides an uncertainty-aware regional accounting framework rather than a fully observed annual reconstruction of historical forest composition.

Forests doi: 10.3390/f17080866

Authors: Bingpeng Qu Xinyuan Mo Peisheng Ye Yinjun Zhao Liang Wei Yanfei Wei Ying Jiang Baopeng Lu Wei Zhou Gang Hu Xinyu Wang

Objective: Forestry management produces abundant residues including wood chips, fallen leaves and bark. Reusing them as urban organic mulches improves soil quality, mitigates soil erosion and optimizes urban green space ecology. This study analyzed the water-holding characteristics of four typical forestry residues to guide urban mulch selection. Methods: Soaking lab tests were conducted on pine bark (PB), oak leaves (OLs), pine needles (PNs), and fir wood chips (FWCs) to monitor dynamic variations in water-holding capacity and absorption rate over soaking time, with data fitted by mathematical models. Results: All forestry residues exhibited considerable water-holding capacity, with OLs showing the highest water-retention performance (175.67 t/ha, 145.42%), effective interception capacity (119.83 t/ha) and interception rate (99.19%) among all tested materials, followed by FWCs. The water-holding capacity increased rapidly and then leveled off with prolonged soaking time, and this trend conformed to a logarithmic equation, expressed as Q = a·ln(t) + b. Water absorption peaked at 15 min before declining slowly until equilibrium, and this dynamic process was well fitted by a power function, expressed as V = k·tn. Conclusions: Given their superior water-holding characteristics, OLs and FWCs are highly recommended as preferred organic mulches for urban soil applications.

Forests doi: 10.3390/f17080865

Authors: Junjie Yue Huayong Zhang Xiangyi Xue

Climate change has significantly affected the geographical distribution and richness patterns of plant species worldwide. Pinus is a major component of many temperate and montane forests in the Northern Hemisphere and is important for carbon storage, climatic buffering and timber production. Here, we utilized the MaxEnt model and integrated global occurrence records of 113 Pinus species, predicting climatic envelopes and diversity distribution patterns under three emission scenarios for the 2050s and 2070s, while also identifying diversity hotspots, high-decline regions, and conservation gaps. As global overheating and linked climatic variations intensify, climatically suitable areas for Pinus are projected to shift poleward. Using projected climatic envelope contraction as a screening criterion, 7.96%–44.25% of species qualified as climate-vulnerable across scenarios. Additionally, Pinus demonstrates high species richness in North America, the Mediterranean region, and mid-latitude mountainous regions of East Asia. Our predictions reveal that species richness distribution will be notably influenced by climate change, with impacts gradually intensifying as climate change progresses. Fortunately, the current coverage rate of protected areas in diversity hotspots exceeds 92.31%, and the conservation gaps primarily occur in Mexico. It is anticipated that over 86.46% of hotspot areas will remain protected in the future. However, new conservation gaps may arise in eastern North America and southeastern Europe; these regions should be prioritized in future conservation planning. Our research enhances current understanding of how species might respond to the challenges of climate change while also providing practical guidance for priority conservation planning targeting both biodiversity hotspots and high-decline regions.

Forests doi: 10.3390/f17080864

Authors: Mengxu Zhang Yuqing Chen Yongge Li Meng Zhu

Plant diversity is often expected to enhance soil organic carbon (SOC) storage through greater and more heterogeneous plant inputs, but its relationships with functionally distinct SOC fractions in natural forests remain uncertain. This study compiled published SOC fraction data from 341 surface soil observations in natural forests across China and spatially matched these records with gridded plant alpha diversity, forest age, climate, topographic and soil properties datasets to evaluate biotic and abiotic associations with SOC, particulate organic carbon (POC), mineral-associated organic carbon (MAOC) and MAOC/SOC. Linear regression, multiple regression, piecewise structural equation modelling and stratified analyses were used to evaluate whether plant diversity was associated with the absolute accumulation and relative stabilization of SOC fractions. Plant alpha diversity was negatively associated with ln[SOC], ln[POC] and ln[MAOC] at the national scale, whereas its bivariate relationship with MAOC/SOC was weak. After accounting for forest age and environmental covariates, plant alpha diversity remained negatively related to the absolute contents of SOC fractions while showing a positive association with MAOC/SOC. Forest age was positively associated with ln[SOC], ln[POC] and ln[MAOC], and POC was more strongly related to plant diversity and forest age than MAOC. In contrast, MAOC and MAOC/SOC were more strongly associated with mineral protection potential, soil pH and precipitation background. Structural equation models indicated that mineral protection potential and mean annual precipitation were associated with greater MAOC accumulation and SOC allocation to the mineral-associated fraction, whereas temperature and topography were linked to MAOC partly through indirect associations with soil physicochemical conditions. Stratified analyses showed that plant diversity associations varied among forest types and climatic backgrounds. Additional interaction models showed that mineral protection potential significantly moderated the associations between plant alpha diversity and ln[SOC], ln[POC] and ln[MAOC], with negative diversity associations weakening under higher mineral protection potential. These findings indicate that plant diversity associations with SOC fractions in natural forests cannot be interpreted as universally positive input relationships. Instead, their direction and strength depend on hydroclimatic context and soil mineral protection, especially for the absolute accumulation of SOC fractions.

Forests doi: 10.3390/f17080863

Authors: Bin Wu John L. Innes Shixin Deng Renyi Gui

Accurate estimation of individual (culm-level) leaf area (LA) is essential to quantifying canopy structure, productivity, and carbon dynamics in bamboo plantations, yet it is often constrained by limited field data and high measurement costs. Using destructive sampling data from 52 Dendrocalamus brandisii culms in Sanya, China, we evaluated allometric models, regression approaches, and machine learning algorithms for estimating individual LA. Candidate models were built from diameter at breast height (DBH), culm height (H), and their combinations and were assessed via five-fold cross-validation, bootstrap uncertainty analysis, and the small-sample corrected Akaike Information Criterion (AICc). DBH was the dominant predictor of LA (r = 0.826), whereas adding H yielded no improvement due to strong collinearity (r = 0.922). The simple DBH-based power-law model (LA=a·DBHb, b ≈ 1.8) achieved the best balance between accuracy and parsimony, explaining ~61% of the cross-validated variance with stable bootstrap parameters. Although Random Forest showed high in-sample fit (R2 = 0.942), its cross-validated performance was low (R2 = 0.496), indicating overfitting when using small samples. These results demonstrate that DBH-based allometric models provide a robust, interpretable, and cost-effective tool for large-scale biomass and carbon stock assessment in D. brandisii plantations.

Forests doi: 10.3390/f17080862

Authors: Bo Wang Zhenya Yang

Interplanting Paeonia lactiflora Pall. under Phyllostachys edulis (Carrière) J. Houzeau (moso bamboo) forests forms an innovative agroforestry intercropping system. This practice has great potential to improve economic benefits and maintain ecosystem stability of moso bamboo forests. Nevertheless, the physiological and growth adaptation mechanisms of P. lactiflora in the understory microenvironment of moso bamboo are still poorly understood. In this study, a two-factor field experiment was conducted to examine how moso bamboo stand density (0, 1200, 1800, 2400 plants·ha−1) and cultivation pattern (bag cultivation, field cultivation) shape the growth, root traits, and resource allocation of P. lactiflora. The results showed that under bag cultivation, the low bamboo stand density (1200 plants·ha−1) promoted biomass accumulation in P. lactiflora leaves, stems, and roots, and facilitated root elongation and radial thickening. Under this condition, P. lactiflora adopted a root-prioritized growth strategy and preferentially allocated nitrogen and phosphorus to leaves and roots. For field cultivation, P. lactiflora growth was inhibited by dual stresses of aboveground shading and underground interspecific root competition. To cope with such stress, P. lactiflora prioritized leaf growth, allocated more nitrogen and phosphorus to leaves, and developed thinner roots. This study reveals the differential growth, root plasticity, and resource allocation strategies of P. lactiflora in response to dual stresses of aboveground shading and underground root competition from moso bamboo, filling the research gaps regarding multi-factor adaptation mechanisms of understory herbaceous plants in moso bamboo forests. The optimal undercropping regime combining low moso bamboo stand density with bag cultivation pattern is identified. These findings offer practical references for the efficient and sustainable management of bamboo–peony agroforestry systems and are critical for balancing the economic benefits of moso bamboo stands and maintaining the stability of understory ecosystems.

Forests doi: 10.3390/f17080861

Authors: Jifeng Deng Yueyao Li Yanfeng Bao Yifan Wang Rui Guo Yong Fu Ruiping Hou Hong Yan

Continuous sap-flow monitoring is a key approach for understanding water-use strategies of shelterbelt species in semi-arid sandy lands. This study investigated two tree species (Populus alba var. pyramidalis Bge. and Pinus sylvestris var. mongholica Litv.) and two shrub species (Salix psammophila C. Wang & C. Y. Yang and Atraphaxis bracteata Losinsk.) in the Zhanggutai region, southern Horqin Sandy Land. Sap flow, environmental variables, and precipitation were continuously measured during the 2019–2020 growing seasons. Stomatal conductance (gs) and its sensitivity to vapor pressure deficit (VPD) were evaluated. Precipitation dropped from 302.3 mm in 2019 to 106.3 mm in 2020. Daily sap flow peaked mid-season and declined by 21.9%–29.2% during 2020. VPD and solar radiation were primary drivers with narrow response lags. Trees exhibited higher gs and stronger stomatal sensitivity than shrubs, showing steeper declines as VPD rose, which indicates key drought adaptation and protective mechanisms. Conversely, shrubs maintained a moderate and more stable gs profile throughout the growing season. In 2020, soil water deficits may force stomatal closure, causing a pronounced drop in baseline gs and a subsequent decline in sensitivity across all species. This widespread environmental decoupling indicates a critical shift from an atmospheric demand-limited regime during the wet year to a supply-limited regime during the drought year. Overall, trees demonstrated more pronounced stand-scale hydroclimatic sensitivity than shrubs. Given the persistent water consumption by shrubs, our results suggest tree species may offer advantages in later forest restoration stages. Nevertheless, further studies integrating biomass growth and ecosystem water balance are needed to optimize sustainable shelterbelt management.

Forests doi: 10.3390/f17070860

Authors: Weiya Xue Ruohan Wang Hui Zhou Cancan Zhao Fanglong Su Lei Su

Litter and understory are key components of forest ecosystems, playing vital roles in soil carbon inputs and microhabitat regulation. Their removal is a common forest management practice: litter removal (L) reduces fire and pest risks while promoting nutrient cycling, whereas understory removal (U) alleviates nutrient competition between understory plants and trees. However, the combined effects and underlying mechanisms of litter removal (L) and understory removal (U) on soil nematode communities remain unclear. This study investigated the individual and interactive effects of L and U on soil nematode communities in a coniferous–broadleaved mixed forest in a subtropical–warm temperate transition zone. The results showed that L significantly reduced soil nematode abundance by 18.1%, increased the relative abundance of bacterivores and omnivores-predators by 21.1% and 103.3%, respectively. U significantly elevated the relative abundance of fungivores by 30.8%, while both L and U reduced the relative abundance of plant-parasitic nematodes. Significant interactive effects between L and U were observed on soil nematode abundance, relative abundances of fungivores, plant-parasites, maturity index, and plant parasite index. Litter plus understory removal (LU) alleviated soil nematode resource limitation through synergistic regulation of resource pulses and microhabitat modification. Faunal analysis based on structure and enrichment indices indicated that LU enhanced food web structural complexity and resource-use efficiency. Redundancy analysis identified microbial biomass carbon, microbial biomass nitrogen, and soil total carbon as key drivers of nematode community differentiation. This study reveals the synergistic regulatory patterns of litter and understory vegetation on soil nematode communities, providing a theoretical reference for understanding the responses of soil nematodes to understory disturbance during the growing season in climate transitional forests, and offering basic data for long-term monitoring and forest soil management.

Forests doi: 10.3390/f17070859

Authors: Jiaming Gu Dengping Xu Chengyan Gu Weiqun Cao Dian Gong Lan Xu

Accurate land-use polygon mapping for forest-oriented natural resource monitoring requires both image-based class prediction and the reconciliation of heterogeneous geospatial semantics. In operational mapping, land survey, forestry survey, and natural resource monitoring datasets often differ in classification systems, management objectives, boundary rules, and mapping scales, causing semantic conflicts when overlaid or forced into one-to-one categories. To address this issue, this study proposes a topology-aware land-use polygon-mapping framework that integrates multi-source semantic representation learning, semantically guided relation learning, and topology-constrained polygon optimization. In the experiments, remote sensing imagery provides visual evidence, the Third National Land Survey (TNLS) and forestry survey (FS) datasets are encoded as source-specific auxiliary semantic priors, and the natural resource integrated monitoring (NRIM) data serve only as reference labels for training and evaluation. Rather than resolving cross-source conflicts using predefined rules, the framework learns a unified land-use representation, transforms semantic boundary cues into a vertex-edge topology graph, and reconstructs GIS-compatible polygons through topology-constrained polygon optimization. In a representative forest–agricultural landscape, the method achieved an mIoU of 79.86%, an APLS of 56.82%, and a TOPO-F1 of 54.56%. These results suggest that learnable semantic harmonization and topology-aware polygon generation can improve the semantic consistency and vector reliability of land-use products for forest and natural resource monitoring.

Forests doi: 10.3390/f17070858

Authors: Seyed Yasser Mohseni Zonouzi Farhad Samadzadegan

High-precision mapping of tree species composition is essential for sustainable forest management, biodiversity assessment, and ecosystem monitoring. Airborne hyperspectral imagery provides rich spectral and spatial information that enables detailed species discrimination. However, traditional single-stream convolutional neural networks (CNNs) often fail to fully exploit multi-dimensional features and are susceptible to spectral redundancy. In this study, we propose the MS-CBAM-TSCNet (Multi-Stream Convolutional Block Attention Deep Neural Network), a novel architecture specifically designed for tree species classification using aerial hyperspectral data. The proposed model integrates three parallel processing streams: a 1D spectral branch for capturing reflectance signatures, a 2D spatial branch for modeling contextual patterns, and a 3D spectral–spatial branch enhanced with Convolutional Block Attention Modules (CBAMs) to adaptively recalibrate channel-wise and spatial–spectral features. An adaptive gated fusion mechanism with attention-based weighting is introduced to dynamically combine the complementary representations extracted from the three streams, improving robustness to spectral redundancy and class imbalance. The method was evaluated on an airborne HyMap hyperspectral dataset (125 bands, with 4 m spatial resolution) acquired over a mixed boreal forest in Karlsruhe, Germany, comprising five dominant tree species. Using five-fold cross-validation on an augmented dataset, the MS-CBAM-TSCNet achieved an overall accuracy of 96.8%, a Kappa coefficient of 0.96, and a macro F1-score of 0.966, outperforming conventional 1D, 2D, and 3D CNNs, as well as a hybrid CNN-SVM approach across all evaluation metrics. An ablation study further confirms the complementary contributions of the multi-stream architecture, CBAM attention, and adaptive gated fusion. Pixel-wise classification maps demonstrate improved boundary delineation and reduced misclassification in mixed stands, highlighting the effectiveness of the proposed framework for operational forest inventory and ecological monitoring.

Forests doi: 10.3390/f17070857

Authors: Catherine R. Henry Douglas R. Pearsall Michael B. Walters

Tree regeneration density and species diversity foretell future forest resilience in the face of changing climate, disturbance regimes, and pest and pathogen outbreaks. However, studies characterizing regeneration composition patterns and their multiple interacting drivers, particularly at regional scales, are scarce. Here, we characterize tree regeneration and associated driving factors for the Northwoods ecoregion, encompassing northern Michigan, Wisconsin, and Minnesota, USA. With data from the USDA Forest Service Forest Inventory and Analysis, we modeled current species richness and density of tree regeneration (stems taller than 30.48 cm (hardwoods) or 15.24 cm (conifers) and <2.54 cm diameter at 1.37 m height) as a function of climate, stand composition, ownership, harvest history, and deer use for the six most common forest groups in the Northwoods. By forest group, we also analyzed recent 20-year changes in tree regeneration richness, total density, and density of key species. Our results suggest tree regeneration abundance and richness are generally associated positively with canopy diversity, recent harvesting, and total annual precipitation; negatively with temperature and canopy basal area; and have few significant associations with deer use and ownership. Although species richness has increased over the past two decades, total abundance and abundance of several key species (such as Acer saccharum Marsh. and Quercus rubra L.) have declined, while subcanopy species (e.g., Amelanchier species Medik.) have proliferated, suggesting potential shifts in stand dynamics including future composition and ecosystem services. Our results suggest that harvest may be a viable tool to promote a wider range of regenerating tree species via increasing understory light availability. Declining regeneration of key ecological species at a regional scale confirms managers’ concerns of insufficient regeneration and highlights the potential for future forest compositional change.

Forests doi: 10.3390/f17070856

Authors: Mario Blanco-Camarillo Alejandra Miranda-Carrazco Caliope Mendarte-Alquisira Martha Hernández-Rodríguez Marco P. Carballo-Sánchez A. Darío Delgadillo-Díaz Julián Delgadillo-Martínez

Land-use change is a major driver of biodiversity loss and ecosystem transformation in forest landscapes. Different land-use systems frequently exhibit differences in belowground microbial communities and soil properties. Accordingly, this study compared soil microbial abundance, diversity, community composition, predicted functional potential, and soil fertility between adjacent pine–oak forest and coffee plantation sites in the Sierra Norte de Puebla, Mexico. Soil samples were analyzed using conventional microbiological methods, soil fertility assessments, and metagenomic sequencing on the DNBseq platform. Metagenomic analyses revealed differences in the taxonomic composition of bacteria, archaea, eukaryotes, and viruses between the two land-use systems. Taxonomic richness increased from 393 taxa in the pine–oak forest to 428 taxa in the coffee plantation, whereas forest soils exhibited a more balanced microbial community structure and coffee plantation soils showed a greater representation of microbial groups associated with environmental adaptation and nutrient cycling. Functional annotation based on the COG and KEGG databases indicated that broad predicted functional profiles remained largely conserved despite taxonomic differences, reflecting similar distributions of predicted functional categories between the two land-use systems. Soil fertility analyses showed higher concentrations of ammonium nitrogen (15 vs. 4 mg kg−1) and available phosphorus (2.6 vs. 1.5 mg kg−1) in coffee plantation soils, whereas forest soils contained greater organic matter (8.1% vs. 7.0%). Overall, these findings indicate that the coffee plantation site exhibited a microbial community structure that differed from that of the adjacent pine–oak forest, while both systems exhibited broadly similar predicted functional profiles inferred from gene annotations. These observations are consistent with differences associated with land use under the environmental and management conditions evaluated.

Forests doi: 10.3390/f17070855

Authors: Shengqun Chen Tao Zhou Yajun Zeng Na Hou

To evaluate the effectiveness of microsatellite (SSR) markers for verifying the authenticity of walnut controlled-cross offspring, seven controlled-cross combinations were established using improved and widely cultivated walnut varieties from Guizhou Province, China, generating a total of 108 candidate offspring. Among 60 previously reported SSR primer pairs, 15 loci exhibiting stable amplification and clear genotyping profiles were selected for analysis. Parentage identification was conducted using the genotype exclusion and maximum likelihood methods, and the applicability of each method was assessed through genetic diversity and cluster analyses. The 15 SSR loci detected a total of 68 alleles, with an average of 4.53 alleles per locus. The polymorphism information content (PIC) ranged from 0.017 to 0.608, with a mean value of 0.396. The genotype exclusion method confirmed 76 offspring as genetically consistent with their recorded parental combination, corresponding to an overall identification rate of 70.37%. In the maximum likelihood analysis, 27 offspring were assigned to their most likely parent pairs when both parents were unknown, with an identification rate of 25.00%. When the maternal parent was known and only the paternal parent was unknown, 47 offspring were successfully assigned, increasing the identification rate to 43.52%. Cluster analysis showed that most offspring clustered near their corresponding parents, although some individuals deviated from their original cross combinations, suggesting allele sharing or complex genetic origins among the parental materials. The shared maternal parent structure, closely related paternal backgrounds, high-frequency alleles, and null alleles may jointly influence the efficiency of SSR-based parentage assignment. Compared with the maximum likelihood method, the genotype exclusion method showed greater practical stability for verifying recorded cross combinations in a structured walnut breeding population characterized by a shared maternal parent, multiple closely related paternal parents, and moderate SSR polymorphism. These findings indicate that likelihood-based parentage assignment should be interpreted cautiously when candidate parents are genetically similar and marker informativeness is limited. This study provides a technical reference for authenticity verification of walnut controlled-cross offspring, pedigree management, and marker-assisted breeding.

Forests doi: 10.3390/f17070854

Authors: Yunan Cao Tangyi Peng Qingshan Yang

Climate change and intensified forest destruction are severely threatening the habitats of numerous wildlife species and plants. Known for its roots, Eleutherococcus nodiflorus (Araliaceae) is a plant used in traditional Chinese medicine, which contains diverse active compounds with significant medicinal value. However, studies indicate its wild populations are undergoing an accelerating decline due to combined pressures from climate change and human activities. To elucidate the climate change response of E. nodiflorus habitat suitability, we used the ENMeval package to develop an optimized MaxEnt model, incorporating 184 occurrence records and 12 environmental factors. Under the SSP1-2.6 and SSP5-8.5 climate scenarios, we simulated and projected the potential distribution of this species across China for the current period and four future time intervals (2021–2040, 2041–2060, 2061–2080, and 2081–2100). The results indicate that key environmental factors governing the distribution of E. nodiflorus include November precipitation, January minimum temperature, temperature seasonality, and June minimum temperature. Currently, the suitable habitat for E. nodiflorus spans approximately 1.38 × 106 km2 and is predominantly located in central, eastern, and southern China. The high-suitability habitats are concentrated in Hunan Province, southern Anhui, and eastern Zhejiang. According to model projections under both climate scenarios, the suitable habitat of E. nodiflorus will first expand and then contract, while its distribution centroid moves generally toward higher latitudes. Under the trend of ongoing global warming, this study provides valuable references for formulating effective climate change adaptation plans and protecting biodiversity.

Forests doi: 10.3390/f17070853

Authors: Ifigeneia Morfopoulou Ioannis P. Kokkoris Ioannis Mitsopoulos Giorgos Mallinis

Disturbance and vegetation-recovery monitoring is gaining growing attention in remote sensing-based studies, especially in studies focusing on protected areas. Despite this growth, the methodological diversity and the research themes addressed across these studies have not yet been systematically examined. This systematic review examines peer-reviewed studies published after 2015 to identify and document how disturbances and post-disturbance recovery are monitored using satellite Earth Observation data. We systematically reviewed 105 studies, following the PRISMA and PSALSAR guidelines, and classified the publications by disturbance type, ecosystem type, geographic region, satellite and auxiliary datasets, analytical methods, and validation approaches employed. The results reveal that the research is concentrated in a small group of countries and predominantly focused on forest ecosystems. Disturbance detection dominates the research literature, while recovery modeling and long-term predictive analysis remain underexplored. Validation practices are highly inconsistent, with limited use of standardized approaches. Overall, this review highlights substantial methodological progress over the past decade and identifies research gaps in disturbance and recovery assessment, multi-sensor integration, and alignment with emerging biodiversity and restoration policy frameworks.

Forests doi: 10.3390/f17070852

Authors: David Efraín Hermosillo-Rojas Alfredo Pinedo-Alvarez Pablito Marcelo López-Serrano Jesús Alejandro Prieto-Amparán Eduardo Santellano-Estrada Martín Martínez-Salvador

Estimation of forest biomass and surface fuels is essential for wildfire risk assessment, carbon accounting, and ecosystem management in semi-arid forests. This study evaluated Sentinel-2 spectral indices and Gamma generalized linear models (GLMs) for estimating aboveground live biomass, forest floor biomass, and downed woody debris in oak–pine forests of Northern Mexico. Spectral predictors were grouped according to chlorophyll activity, vegetation vigor, physiological condition, and soil/background correction effects. Measurements of live biomass, forest floor biomass, and downed woody debris were linked to Sentinel-2 spectral information. Aboveground live biomass was most strongly associated with the chlorophyll-related index CIre8A (p < 0.0001), whereas both forest floor biomass and downed woody debris showed stronger relationships with indices associated with red–NIR reflectance gradients, vegetation senescence, and soil/background correction effects, including the Normalized Difference Vegetation Index (NDVI), the Alpha-weighted Red–NIR Vegetation Index (PVIα), the Normalized Pigment Chlorophyll Index (NPCI), and the Atmospherically Resistant Vegetation Index (ARVI) (p < 0.05). Single-index Gamma GLMs showed significant predictive relationships (p < 0.05), supporting the use of individual Sentinel-2 indices as practical predictors of biomass and surface fuels. In contrast, multivariate models combining several spectral indices were affected by collinearity and parameter instability. Principal Component Analysis (PCA) integrated four representative indices into a single orthogonal predictor. The first principal component (Prin1) explained 90.30%–95.25% of total spectral variance, eliminated collinearity effects (VIF = 1), and produced highly significant Gamma GLMs across all biomass components (p ≤ 0.0009). PCA-based models also yielded lower AIC and BIC values, providing the most parsimonious framework when multiple spectral predictors were combined. These results indicate that individual spectral indices offer practical alternatives for biomass estimation, whereas PCA provides a robust approach for integrating complementary spectral information while maintaining model stability.

Forests doi: 10.3390/f17070851

Authors: Yuti Chen Lijuan Xiao Chenyuling Wang Shuangqi Pu Xiangyun Shi

Rapid urbanization has been associated with substantial structural adjustments and ecological risks in peri-urban agroforestry landscapes. Taking Pidu District, Chengdu, China, as a representative peri-urban region, this study investigated the spatiotemporal evolution of agroforestry landscapes and their ecological risks from 2000 to 2020. Utilizing multi-period land-use data, we integrated landscape pattern indices, an ecological risk assessment model, etc. The results showed that the agroforestry landscape area decreased by 24.53%, from 275.39 km2 to 207.83 km2, a decline primarily tied to the expansion of construction land. Ecological risk increased continuously over the study period, with high-risk areas concentrated in the rapidly urbanizing southern region and low-risk areas mainly distributed in the northern agricultural zone. Meanwhile, landscape fragmentation intensified, as reflected by increasing patch subdivision and declining landscape integrity. Bivariate spatial autocorrelation analysis revealed a positive spatial association between fragmentation and ecological risk, indicating that structural degradation of agroforestry landscapes is an important factor of ecological risk escalation. Overall, rapid urbanization in Pidu District was accompanied by the coupled processes of agroforestry landscape shrinkage, fragmentation, and ecological risk growth. These findings provide scientific support for ecological risk zoning management and agroforestry landscape conservation in similar rapidly urbanizing regions.

Forests doi: 10.3390/f17070848

Authors: Hyewan Jun Ji-Hyeok Park Tomonori Kume Seonghun Jeong

Throughfall kinetic energy (TKE) is a physically based index of raindrop-driven splash erosion potential in forest ecosystems. In Japanese cypress plantations, TKE shows substantial spatial heterogeneity beneath the canopy, but the stand structural factors controlling this variability remain poorly understood. Under-canopy structures, such as the dead-branch layer in unmanaged stands, may contribute to localized variation in throughfall erosivity. This study quantified TKE in two unmanaged Japanese cypress plots and examined whether stand structural attributes, particularly the lowest dead-branch height (Hdb), explained within-stand variability. Throughfall (TF) gauges and sand-filled splash cups were co-located at 20 measurement points in each plot, and gross rainfall (GR) and free kinetic energy (FKE) were measured in an adjacent open space. TKE beneath the canopy exceeded FKE, indicating canopy enhancement of rainfall erosivity. Stand-mean TKE was similar between the two plots, whereas TKE varied markedly among measurement points within stands. Hdb showed a significant but modest positive association with TKE (r = 0.447, R2 = 0.20, p < 0.01) in both plots. These results suggest that the under-canopy structure, including Hdb, is associated with within-stand spatial heterogeneity in throughfall erosivity. The normalized stand-mean TKE (unit TKE¯) values were consistent with the reported relationship between stem density (SD) and unit TKE¯. These findings highlight the importance of considering Hdb and SD in spatially explicit assessments of potential splash erosion risk.

Forests doi: 10.3390/f17070850

Authors: Xiaoyan Zhang Ruonan Zhuang Zhidong Zhuang Weiguo Zhong Chenggong Liu Mingsheng Sun Yinyin Fu Yanhui Qiao Shuangyun Li Shanwen Li Jinmao Wang Minsheng Yang

Understanding genotype × environment interactions (G × E) is essential for selection of stable and productive clones in poplar breeding. However, the performance of hybrid poplar clones often varies unpredictably across sites, hindering efficient regional deployment. In this study, we evaluated the growth performance of 21 hybrid Populus section Aigeiros clones under five contrasting environmental conditions (YI, SHAN, SHEN, FEI, and JUAN). At the end of the growing season, we measured tree height (H), diameter at breast height (DBH), and individual tree volume (V). Both parametric and non-parametric stability statistics were used to assess individual V and fitted a mixed linear model in ASReml–R to generate best linear unbiased prediction (BLUP) values for subsequent genotype plus genotype-by-environment (GGE) biplot analysis. All measured traits exhibited substantial phenotypic variation, with coefficients of variation ranging from 17% to 43%. Genotype, environment, and G × E interaction effects were all highly significant (p < 0.01). The GGE biplot explained 89.88% of the total variation in individual V across test environments. Clones 1617 and 1618 exhibited high productivity, broad stability and strong adaptability across sites. Site discrimination and representativeness analyses revealed that SHAN, SHEN, FEI and JUAN were more informative, whereas YI showed weaker genotype differentiation. Clones 1617 and 1618 were particularly well adapted to FEI and JUAN, while clones 81, 1618, 13–22, 1607, I–107 and 1617 performed favourably in the other mega-environment. Our results indicate that integrating BLUP with GGE biplot analysis provides a robust framework for dissecting G × E and guiding clone selection in multi-environment poplar trials. The study provides valuable insights for refining poplar deployment strategies under diverse environmental conditions.

Forests doi: 10.3390/f17070849

Authors: Nan Wang Hao Wang Weixuan Wei

As high-density cities face severe conflicts between urban expansion and limited ecological space, exploring the potential drivers of carbon sequestration within urban green spaces is crucial. The overarching aim of this study is to establish an interpretable, model-based analytical framework for assessing the Annual Carbon Fixation Rate (ACFR). To address the limitations of linear models and “black-box” machine learning algorithms, this study analyzed 149 urban parks in Nanjing by coupling Sentinel-2 high-resolution data with a Random Forest algorithm and the SHAP framework to model Annual Carbon Fixation Rate. The model achieved high predictive reliability (R2 = 0.9690). This study quantitatively identified critical nonlinear thresholds: an impervious surface proportion exceeding 30% is associated with a structural decline in carbon sinks, while the optimal Leaf Area Index interval for maximum efficiency is 2.5–3.5. Moreover, the present research identified a potential model-derived ecological compensation effect; optimizing vegetation community structures under high anthropogenic disturbance showed a 23.9% higher modeled marginal ACFR response compared to low-disturbance habitats. This explainable framework attempts to translate complex model-derived biophysical associations into referenced quantitative thresholds. Importantly, the ACFR and derived thresholds represent remote sensing-based model estimates rather than field-measured ecological causality, serving as exploratory planning references. These findings challenge the assumption that greening is inefficient in degraded environments and provide concrete control indicators for targeted micro-renewal and sustainable urban regeneration.

Forests doi: 10.3390/f17070847

Authors: Zemouri Zohra Bou Dagher-Kharrat Magda Siljak-Yakovlev Sonja

The carob tree (Ceratonia siliqua L., Fabaceae) is an ecologically and economically significant species of the Mediterranean basin, yet its cytogenetic and genomic organisation have remained largely uncharacterised. Here we present the first comprehensive molecular cytogenetic characterisation of C. siliqua, combining conventional karyotyping, fluorochrome banding, fluorescence in situ hybridisation (FISH), and flow cytometric genome size estimation across 29 accessions spanning the Mediterranean basin. A uniform diploid chromosome number of 2n = 24 was confirmed across all 14 populations examined, including Algerian, French, and Lebanese accessions, with no karyotypic variation detected regardless of geographic origin, altitude, or cultivation status. Karyotype analysis revealed a bimodal chromosome set comprising two large metacentric pairs and ten smaller pairs, with an intermediate asymmetry class (AsI = 60.09; R = 2.71). Physical mapping of ribosomal RNA gene families by FISH identified three chromosome pairs bearing 35S rDNA loci, all co-localising with GC-rich CMA3-positive heterochromatin at satellite regions, and a single 5S rDNA locus at the telomeric region of a distinct chromosome pair, corresponding to the S-type arrangement. DAPI staining revealed an additional class of AT-rich constitutive heterochromatin at centromeric positions, compositionally and positionally independent of the rDNA arrays. Genome size was strikingly conserved across all 23 accessions assessed (2C = 1.10–1.23 pg; overall mean 1.14 ± 0.03 pg), with no significant variation attributable to geographic origin, altitude along an Algerian gradient (162–950 m a.s.l.), cultivation status, or sex. The near-identical genome sizes recorded in female and male individuals provide no cytometric evidence for heteromorphic sex chromosomes in this dioecious species. These results establish a stable genomic and cytogenetic baseline for C. siliqua across its Mediterranean range and provide a reference framework for future comparative cytogenetics, molecular marker development, and breeding programmes targeting this increasingly valued climate-resilient crop.

Forests doi: 10.3390/f17070845

Authors: Zheng Zhao Guoxiang Zhu Siyu Yuan Jinyu Shen Wei Duan

Community-based forest ecotourism is an important livelihood pathway for communities around protected forests, but household agritourism operators often face ecological regulations, seasonal demand and heterogeneous tourist expectations. These conditions increase information asymmetry and make service matching difficult. This study examines how two-way information disclosure affects business performance in community-based forest ecotourism. Drawing on social penetration theory, we test a chained mechanism linking two-way information disclosure to operational performance. Based on 780 valid questionnaires from agritourism operators and core family managers around Giant Panda National Park, China, this study measures information disclosure practices, service responsiveness, operator-side perceptions of tourist responses and self-reported business performance. The results show that seller- and buyer-side information disclosure significantly enhance perceived identification. Seller information disclosure has relatively stable effects on customer orientation, perceived quality and operational performance, whereas buyer information disclosure mainly works through perceived identification. Perceived quality, perceived value and satisfaction act as partial transmission channels. Heterogeneity analysis shows stronger effects among low-income and newly established operators. The findings provide micro-level evidence for reducing expectation mismatch and strengthening sustainable livelihood capacity in forest protected-area communities.

Forests doi: 10.3390/f17070846

Authors: Luis Carlos de Freitas Márcio Lopes da Silva Francisco de Assis Costa Ferreira Nilton Cesar Fiedler Cassio Furtado Lima Roldão Carlos Andrade Lima Luciano José Minette Leonardo França da Silva Stanley Schettino Victor Crespo de Oliveira Lucas Moraes Rufini de Souza

This study evaluated the economic viability and risk of a eucalyptus forestry project by integrating deterministic and probabilistic economic analyses. Operational costs for motor–manual harvesting, manual extraction and loading, and forest transportation were estimated using standard cost models, while silvicultural, road maintenance, and transportation costs were obtained from operational records. Economic viability was assessed using Net Present Value (NPV), Internal Rate of Return (IRR), Equivalent Annual Value (EAV), and Average Production Cost (APC). Economic risk was evaluated through Monte Carlo simulation (10,000 iterations), considering ±10% variation in interest rate, transportation distance, harvesting productivity, labor, fuel, lubricant, and road maintenance costs, followed by sensitivity and correlation analyses. The project was economically viable, presenting an NPV of USD 110.11 ha−1, an IRR of 8.0%, an EAV of USD 20.43 ha−1 year−1, and an APC of USD 29.11 m−3. Transportation distance showed a limited operational slack of only 10 km when land cost was considered, indicating that the project operates close to its economic limit. Monte Carlo simulation indicated an 11.5% probability of economic infeasibility, while interest rate, transportation distance, and manual loading cost exerted the greatest negative influence on NPV. The integrated deterministic and probabilistic approach enabled the identification of critical operational thresholds for transportation distance, timber price, wood productivity, and land cost under the evaluated conditions, providing practical decision-support parameters for transportation planning, cost management, and economic risk assessment in similar forestry projects.

Forests doi: 10.3390/f17070844

Authors: Jacek Piętka Michał Małecki Magdalena Kędzierska Mirela Tulik Marcin Studnicki Marta Aleksandrowicz-Trzcińska

Sustainable development in wood technology demands eco-friendly alternatives to conventional preservatives, positioning nanotechnology as a promising frontier for green wood protection. The antifungal potential of silver nanoparticles (AgNPs) against the brown-rot agent Fomitopsis pinicola was investigated in vitro, alongside an assessment of their protective performance on Scots pine wood. AgNPs were tested at 5, 25, 50, and 100 ppm in vitro, with an additional 200 ppm concentration included in the wood-decay test. In the in vitro assays, lower concentrations (5 and 25 ppm) stimulated radial mycelial growth, 50 ppm showed no effect, and 100 ppm caused growth inhibition. In contrast, all tested concentrations enhanced the decay resistance of pine wood. Average wood mass loss ranged from 4.9% to 8.1% after 2 months and from 10.9% to 18.6% after 4 months, with the maximum protective effect observed at 50 ppm. While AgNPs did not entirely prevent F. pinicola-induced decay, they significantly mitigated mass loss. These findings highlight the potential of AgNPs for the short-term preservation of freshly harvested timber, particularly storm- or disaster-damaged wood stored in forests or log yards prior to processing.