IntroductionEcological stoichiometry assessment provides insights into the dynamic interactions between the leaf–litter–humus–soil (LLHS) in different forest types. However, research on ecological stoichiometry in mixed and pure forest ecosystems is relatively weak in the karst region of southwestern China.MethodsWe investigated how stand types influence the stoichiometric characteristics of carbon (C), nitrogen (N), and phosphorus (P) across the LLHS continuum. Leaf, litter, humus, and soil samples were collected from an evergreen coniferous forest (Cryptomeria japonica var. sinensis Miquel; CJ), a deciduous broadleaf forest (Liquidambar formosana Hance; LF), and a mixed forest composed of both species (C. japonica var. sinensis × L. formosana; CJ × LF) in the fragile karst ecosystem of Southwest China.ResultsThe results showed that stand type had a significant effect on the concentrations of C, N, and P and on the stoichiometric ratios of all LLHS components. Compared with the two pure forests, litter in the mixed forest exhibited significantly higher C/N and C/P ratios, while N and P concentrations were significantly lower. In the broadleaf forest, leaf C/P and N/P ratios were significantly higher than those in the mixed forest and C. japonica monocultures, whereas leaf P concentrations were significantly lower than C. japonica monocultures. Compared with the mixed and broadleaf forests, humus C/N and C/P ratios showed significantly higher in the coniferous forest, while N and P concentrations and the N/P ratio were significantly lower. In the 0–20 cm soil layer, mixed forests had significantly higher C concentration, C/N ratio, and C/P ratio than the two pure forests (p < 0.05). The P nutrient resorption efficiency of plant nutrients in the study area (40.07%–53.69%) was higher than that of N (10.43%–27.04%). Leaf C, N, P, C/N, N/P correlated positively with litter (p < 0.01); leaf N, P, C/N, C/P correlated negatively with humus. Leaf N, C/N, C/P linked positively, leaf P negatively with soil (p < 0.01). The explanatory power of litter, humus, and soil for leaf nutrient concentrations and stoichiometric ratios decreased in the order litter (50.8%) > humus (32.2%) > soil (1.8%).DiscussionOverall, these results indicate that the selection of stand type and dominant tree species is central to forest restoration and management in fragile karst ecosystems and plays a crucial role in maintaining the dynamic balance of C, N, and P in forest ecosystems.
IntroductionTropical dry forests (TDFs) are characterized by marked seasonality in water availability, which regulates the ecophysiological functioning of plant species and shapes resource acquisition and use strategies. We assessed the coordination of functional traits associated with water, carbon, and nitrogen use in dominant leguminous and non-leguminous tree species of a TDF in northwestern Mexico.MethodsStructural, hydraulic, isotopic, and stomatal traits were analyzed, including specific leaf area (SLA), leaf thickness (LT), leaf Nitrogen content (Leaf N), δ15N, intrinsic water-use efficiency (WUEi), stomatal conductance (gₛ), stomatal density (SD), and the leaf water potential gradient (ΔΨleaf). Spearman correlation analyses, non-parametric tests, and principal component analysis (PCA) were used to evaluate patterns of functional coordination among groups and species.ResultsSignificant functional differences between leguminous and non-leguminous species were detected, particularly in traits associated with foliar resource use and water regulation. Non-leguminous species showed greater functional convergence in traits associated with leaf structure and water regulation, whereas leguminous species occupied a broader region of multivariate trait space, although differences in multivariate dispersion between groups were not statistically significant. The PCA explained 64% of total trait variability and indicated that functional differentiation between legume and non-legume species was primarily associated with foliar resource use and water regulation. Correlations among WUEi, ΔΨleaf, LT, and gₛ further indicated coordination among hydraulic, stomatal, and structural traits involved in gas-exchange regulation and maintenance of plant water status.DiscussionFunctional strategies were not organized into strictly conservative or acquisitive categories, but rather along continuous gradients defined by different combinations of hydraulic, stomatal, structural, and resource-use traits. These findings support the interpretation that coordination among multiple functional traits underlies the diversity of ecological strategies.
IntroductionThe growing influence of social media has transformed the ways tourists access information, form perceptions, and engage with environmental issues. However, limited attention has been paid to the psychological processes through which social media shapes pro-environmental behavior, particularly in forest tourism settings. This study investigates the direct and indirect effects of social media on tourists’ pro-environmental behavior through environmental knowledge, environmental attitude, environmental values, and subjective norms.MethodsData were collected from 586 visitors across multiple forest destinations in Shandong Province, China, using a structured questionnaire. The survey instrument underwent expert review, pilot testing, and a translation–back translation procedure to ensure content validity and linguistic equivalence. The proposed model was analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM).ResultsThe results indicate that social media significantly influences environmental knowledge, environmental attitude, environmental values, subjective norms, and pro-environmental behavior. Environmental attitude emerged as the strongest predictor of pro-environmental behavior, while environmental values were most strongly affected by social media. Furthermore, all four mediating variables significantly transmitted the influence of social media on pro-environmental behavior, with the combined indirect effect exceeding the direct effect.DiscussionThese findings suggest that social media functions not only as a source of environmental information but also as a mechanism that shapes tourists’ environmental values, attitudes, and social perceptions. The study contributes to sustainable tourism research by advancing understanding of the psychological pathways through which digital communication environments encourage environmentally responsible behavior.
Forests supply a large and economically significant fraction of the medicinal materials used in traditional Chinese medicine (TCM), comprising woody medicinal taxa, understory-cultivated herbs and forest-dwelling macrofungi. For all three resource classes the therapeutic value, and hence the market price, is tied to geographical origin and to cultivation mode, yet conventional authentication remains slow, destructive and poorly suited to supply-chain deployment. Hyperspectral imaging (HSI) offers a rapid, non-destructive alternative that is well matched to the monitoring requirements of smart forestry. This review evaluates the HSI-based authentication pipeline across three methodological dimensions: spectral preprocessing, feature extraction, and classification modelling, and then maps reported performance onto the three forest resource classes. A structured narrative synthesis of the 2015–2026 literature indicates that deep learning architectures—particularly two-dimensional correlation spectroscopy (2DCOS) combined with residual networks—have been reported to achieve 98–100% classification accuracy for several forest-sourced species under controlled laboratory conditions. Within-study comparisons, in which a single dataset is modelled by several algorithms, show dataset-dependent outcomes rather than a universal deep-learning advantage over partial least squares discriminant analysis (PLS-DA) or support vector machines; values compared across different studies are confounded by differences in species, sample size, instrument and validation design and should not be read as benchmarks. In one fully verifiable within-study example, wavelength selection retained 11.2–16.1% of the original bands with zero to 1.12 percentage points of accuracy loss, while several data-fusion studies reported improvements over their own single-source baselines. These individual results do not establish universal advantages. Critically, no study has directly compared spectral signatures of identical species grown under forest canopy versus open-field conditions—a gap with significant implications for Daodi quality verification and for the certification of understory cultivation as a forest-management practice. External validation, cross-instrument transfer and the confounding effect of a changing climate on metabolite profiles remain the principal barriers to field deployment. Future priorities include standardized spectral databases, portable devices, transfer learning, and explainable AI.
Carbon and nitrogen play crucial roles in soil by influencing its physical, chemical, and biological properties, thereby determining soil fertility and overall health. Biochar is a carbon-rich material with additional elements that can promote plant growth by improving soil quality and nutrient availability. However, its total carbon and nitrogen concentrations vary depending on factors such as feedstock type and pyrolysis conditions. This study evaluated the effects of tree species, tree fraction, and pyrolysis time on the total carbon, total nitrogen, and carbon-to-nitrogen (C/N) ratio of biochar. Biochar was produced from three conifer species (Pinus radiata D. Don, Pinus sylvestris L., and Pinus pinaster Aiton) and three broadleaf species (Betula alba L., Quercus robur L., and Castanea sativa Mill.). In addition, three tree fractions (branches, litterfall, and green leaves) were collected from each species and subjected to pyrolysis at 300 °C for 30, 60, and 120 min. The results showed that, in general, biochar produced from conifer species had higher total carbon concentrations and C/N ratios than biochar derived from broadleaf species. In contrast, biochar from broadleaf species typically contained higher total nitrogen concentrations. Tree fraction also markedly influenced biochar composition. Branch-derived biochar exhibited the highest total carbon concentrations, while biochar produced from green leaves contained the highest total nitrogen concentrations. Moreover, regardless of tree species and tree fraction, pyrolysis time significantly influenced total carbon and nitrogen concentrations and the C/N ratio, although to a lesser extent. These findings highlight the influence of tree species, tree fraction, and pyrolysis time on biochar chemical composition, providing valuable insights into the production of biochar from forest residues with characteristics suitable for improving soil properties and supporting sustainable agricultural management.
Scientifically identifying the coupling characteristics between factor flows and the value of rural ecosystem services is an important prerequisite for promoting sustainable rural development. This study employs a range of analytical methods, including the entropy-weighted linear aggregation method, the entropy-weighted TOPSIS method, the elasticity coefficient model, Spearman correlation analysis, and the geographical detector model, to analyze county-level data from Hunan Province, China (2013–2024). The objective is to identify the coupling characteristics between factor mobility and rural multiple ecosystem service values, and to uncover the mechanisms driving their spatial differentiation. The results reveal that: (1) The coupling relationship can be classified into four types: collaborative, crowding-out, inverse-increment, and lagging. Over the study period, the dominant pattern evolved from collaborative and inverse-increment types toward crowding-out and lagging types. In contrast, the coupling state shifted from relatively high-level systemic coordination to low-level differentiation. Spatially, the crowding-out type is concentrated in the Changsha–Zhuzhou–Xiangtan core region, whereas the lagging type prevails in the western and southern peripheries of Hunan. (2) Urbanization level and the number of new agricultural business entities are the key drivers of spatial differentiation in coupling patterns, with their interaction exhibiting the strongest explanatory power. (3) Responses to factor mobility differ significantly across value dimensions. Excessive concentration of material factors and insufficient supply of non-material factors are major contributors to coupling imbalance. Optimizing factor allocation structures and strengthening local absorptive capacity are essential to promoting the collaborative enhancement of rural multiple ecosystem service values. Future policies should therefore advance the coordinated allocation of material and non-material factors and implement regionally differentiated strategies for rural sustainability and ecological governance.
Sacred natural sites have long been regarded as informal refugia for biodiversity, yet their role in conserving heritage trees that require multi-century persistence remains insufficiently assessed and quantified. This study investigated the diversity, structural characteristics, health condition, and conservation significance of heritage trees in Nanhua Temple, one of the most historically continuous Buddhist monasteries in China. A comprehensive census was conducted by systematically verifying government inventory records, during which species identity, dendrometry characteristics, age structure, and physiological condition were assessed in accordance with national forestry standards. A total of 285 heritage trees representing 13 species were recorded, dominated by Liquidambar formosana (129 individuals, IV = 43.09%), followed by the introduced Camphora officinarum (21.04%), Schima superba (15.14%), and Castanopsis hystrix (12.81%), which together accounted for over 90% of the total importance value. Diameter and age structures exhibited right-skewed distributions, whereas tree height and crown width showed unimodal patterns, indicating a relatively stable population structure with continuous regeneration and old-growth characteristics. The density of heritage trees within the temple far exceeded regional county-level averages in South China. The globally Critically Endangered relict Glyptostrobus pensilis persisted as the oldest cohort (>500 years), represented by three individuals. However, multiple stressors, including invasive vines, incense smoke, termite infestations, and soil compaction, have also been observed. These findings demonstrate that historically continuous Buddhist temple landscapes can serve as important refugia for heritage trees through long-term cultural stewardship and management continuity. While heritage trees in China are already incorporated into the national protection system, the diversity and conservation value of temple-associated heritage trees deserve greater attention in future management and cultural heritage conservation practices, particularly in rapidly urbanizing regions where sacred landscapes continue to preserve important biocultural resources.
Future forest dynamics under climate change will largely depend on the physiological acclimation capacity of the tree species to the increasing environmental stress. We combined carbon and oxygen stable isotope analyses with growth measurements to estimate the effects of atmospheric CO2 and drought stress on intrinsic water-use efficiency (iWUE) and secondary growth in five coexisting tree species (Acer campestre, Fraxinus ornus, Quercus cerris, Quercus pubescens, Tilia tomentosa) in Central Hungary. Generalized additive models explained most of the variation in iWUE (adjusted R2 = 0.77) and growth (adjusted R2 = 0.75). The isotope and iWUE chronologies showed that these species experienced increasing hydroclimatic stress, driven primarily by rising temperatures and vapor pressure deficit. The 12-month water balance (WB12), calculated from the previous September to the current August, was the strongest climatic predictor, showing strong correlations with both Δ13C (r = 0.55–0.73) and iWUE (r = −0.60 to −0.80). Although the species differed in their physiological adaptations, the general pattern of increased iWUE coupled with stagnant or declining growth suggests that elevated atmospheric CO2 could not fully offset the unfavorable effects of increased warming and drying on tree function. Unlike the other species, Q. cerris exhibited only a modest increase in iWUE until around 2010, followed by a more pronounced increase thereafter. The relationships between iWUE and growth reveal fundamental differences among the species in their drought-response strategies. T. tomentosa and F. ornus appear to adopt a more conservative water-use strategy with strongly increasing iWUE and declining growth which may enhance short-term survival but increase long-term vulnerability. In contrast, Q. pubescens and A. campestre maintained growth under increasing iWUE, suggesting broader hydraulic safety margins or deeper rooting. Q. cerris presented an intermediate pattern with stable growth initially, but pronounced decline under severe drought. Beyond these physiological differences, site conditions and landscape structure also appeared to modulate tree responses through local microclimate effects, including evaporative demand. These findings suggest that the forest composition may shift in the drier regions of Central Europe because coexisting species differ markedly in their capacity to withstand increasing drought stress.
IntroductionPhoretic mites associated with bark beetles play important ecological roles in forest ecosystems, yet their diversity and ecological relationships remain insufficiently documented in Turkey. This study aimed to investigate the phoretic mite fauna associated with three economically important bark beetle species, Ips sexdentatus, Ips acuminatus, and Tomicus piniperda) (Coleoptera: Curculionidae, Scolytinae), in the forests of Kastamonu, in Turkey’s Black Sea Region.MethodsPhoretic mites (Acari: Mesostigmata) were collected both directly from the bark beetles and from their galleries. The collected mite specimens were identified to species level using relevant taxonomic literature and identification keys.ResultsA total of 11 Mesostigmata mite species were identified. Ten species, Ameroseius longitrichus, Cercoleipus kuznetsovi, Dendrolaelaps quadrisetosimilis, Dendrolaelaps quadrisetus, Hypoaspis maryamae, Pleuronectocelaeno barbara, Proctolaelaps hystrix, Schizocyrtillus rarus, Schizosthetus lyriformis, and Stratiolaelaps scimitus are reported as new records for Turkey.DiscussionThe findings substantially expand the known diversity of phoretic mites in Turkey and provide important baseline data for understanding mite–bark beetle associations and their ecological roles in forest ecosystems. The documented diversity and interactions may contribute to the development of sustainable forest pest management strategies, particularly through the identification of potential biological control agents and a better understanding of phoretic mite–bark beetle relationships.
IntroductionMediterranean forests are undergoing rapid atmospheric aridification driven by rising temperatures and declining summer precipitation, and vapor pressure deficit (VPD) has emerged as an important co-limiting factor for tree physiological functioning and radial growth. The degree to which rising VPD and seasonal precipitation co-limit intra-annual growth coordination and modulate climate memory in maritime pine (Pinus pinaster Ait.), a foundational Mediterranean species, remains poorly quantified. This study quantified the relative effects of summer VPD, seasonal precipitation, and the intra-annual earlywood-to-latewood carry-over on latewood width, testing whether increasing atmospheric aridity erodes lagged climatic legacies and weakens the carry-over.MethodsWe analyzed earlywood and latewood width chronologies from nine mature maritime pine stands in northern Portugal spanning 1965–2023. Hourly climate reanalysis datasets based (ERA5 and ERA5-land reanalysis) were used to derive seasonal VPD metrics and precipitation totals across ecologically relevant windows. Climate–growth relationships were examined with Generalized Least Squared (GLS) incorporating lagged climatic terms, comparing pre- and post-2000 regimes under two complementary detrending frameworks. Threshold-based VPD accumulative intensity and climate–growth coupling was evaluated across both periods.ResultsSummer VPD imposed a temporally stationary constraint on latewood width, statistically additive to seasonal precipitation, whereas pre-summer precipitation controls were non-stationary, reversing signs between the pre- and post-2000 periods. Summer precipitation remained the strongest predictor in the baseline framework, while VPD prevailed in decadal-trend and anomaly-based analyses, consistent with an additive co-limitation rather than a replacement of precipitation by VPD. After 2000, current-year VPD sensitivity remained stable while lagged climate signals weakened; most importantly, the intra-annual earlywood-to-latewood carry-over provided the strongest overall explanatory power (R2 = 0.30–0.40), remaining statistically independent of VPD and, contrary to our third hypothesis, strengthening rather than weakening in recent decades.ConclusionOur results do not support the displacement of precipitation by VPD or a direct destruction of biological legacies by atmospheric aridity but instead point to an additive co-limitation whose apparent balance depends on the analytical framework adopted. While the lagged (prior-year) climate signal has attenuated since 2000, the intra-annual earlywood-to-latewood carry-over strengthened rather than collapsed and remains the dominant structural driver of latewood formation.
Wildfires historically shaped and sustained global biomes, but climate change, strict fire exclusion policies, and rapid expansion into the wildland–urban interface have fueled an era of unprecedented, high-severity “megafires.” This review synthesizes current literature on the dual nature of wildland fires, categorizing their impacts on material, non-material, and regulating Nature’s Contributions to People (NCP) using the IPBES framework. Grounded in case studies from regions experiencing acute megafires including California, Australia, Canada, Chile, Siberia, Maui, and Los Angeles, we present a conceptual framework illustrating fire's transition from an ecological regulator to a driver of severe NCP degradation. High-severity fires frequently cross ecological thresholds, causing acute detriments like massive timber loss, water quality degradation, disrupted soil microbiomes, and eroded recreational landscapes. Conversely, low-to-moderate severity fires, particularly Indigenous cultural burning practices, remain vital for sustaining these ecosystem contributions. We identify critical research gaps regarding multi-decadal post-fire recovery and sector-specific economic valuations, which are essential for improving decision support. Furthermore, we argue that risk-based NCP accounting must be paired with innovative conservation finance models to fund proactive, landscape-scale fire management. This synthesis underscores the urgent need to shift global land management from absolute fire suppression toward adaptive resilience and co-management, utilizing the NCP framework to evaluate complex trade-offs, target fuel treatments, quantify costs, and drive necessary policy reforms in increasingly fire-prone landscapes.
IntroductionPreferential flow is a key hydrological process controlling rainfall redistribu-tion, subsurface recharge, and ecohydrological functioning in karst ecosys-tems. However, the formation and ecological significance of preferential flow in shallow karst fissure (SKF) soils remain insufficiently quantified.MethodsField dye-tracer experiments with Brilliant Blue FCF were conducted in SKF soils in Xixiu District, Guizhou Province, Southwest China, to characterize vertical flow patterns and identify soil-hydraulic and root controls.ResultsPreferential flow showed strong vertical heterogeneity: Dc was high in the 0–10 cm layer (68.62–98.75%) but decreased rapidly with depth, while maximum stained depth varied from 23.0 to 74.6 cm among fissures, indicating marked spatial variability in subsurface hydraulic con-nectivity. Bulk density (BD) was the strongest negative control on Dc (r = −0.697), whereas total porosity (TP), non-capillary porosity (NCP), saturated hydraulic conductivity (Ks), saturated water content (SWC), capillary water content (CWC), field capacity (FC), root length density (RLD), and root surface area density (RSAD) generally promoted preferential flow development. PLSR further identified BD, SWC, CWC, NCP, TP, FC, and Ks as the main predictors, with VIP values greater than 1. These factors explained approximately 52–55% of the observed variation in Dc. The results indicate that preferential flow in SKF soils is jointly regulated by soil structure, hydraulic properties, and root-induced biopores.DiscussionPreferential flow provides a dual ecohydrological function by enhancing deep water redistribution and epikarst recharge while potentially increasing water leakage from the shal-low root zone. These findings improve the mechanistic understanding of water movement in karst fissure soils and provide guidance for vegetation restoration and water conservation in rocky desertification regions.
Decision making is inherently a complex social and cultural process that is shaped by myriad influential factors both internal and external to the environments, people, and institutions affected. Natural resource management is no exception in this regard. As the Earth’s climate rapidly changes, disturbances increasingly threaten forests across the globe, while the demand for resilient conditions and ecosystem services increases. As risks and threats to forests are building, so are assumptions, uncertainties, and stakes associated with management and mitigation outcomes. Decision support tools (DSTs) serve many functions in landscape and forest management, most centrally in helping decision makers and interest holders cope with complexity and uncertainty. Similarly, increasingly complex data, statistics, ecosystem dynamics, uncertainty, and technological advances have driven the evolution and integration of DSTs into forest and landscape management decision processes. We explore five factors driving DST development and integration into forest ecosystem management: environmental change, risk management, call for transparency, implicit and explicit social contracts, and technological advancement. We identify the challenges that DST growth and expanding deployment have addressed, as well as the emerging dilemmas that their current and future uses are likely to create. As environmental risks mount with changing climate, and computing capabilities continue to advance (e.g., statistical models, artificial intelligence), social norms and priorities are also changing. DSTs are expected to become central to forest and landscape management to help adjudicate the complexities of managed and unmanaged systems, the consequences of management actions and inaction, and their impact on environmental quality and forest resilience.
Tropical dry forests are among the most threatened ecosystems worldwide, yet the mechanisms controlling tree growth at local scales remain poorly understood. The aim of this study was to combine available information on environmental conditions and tree functional traits to better understand their relevance for tree growth in seasonal tropical dry forests. We used data from forest dynamics of six permanent one-ha plots at two elevations (lower elevation deciduous forest: ~600 m a.s.l.; upper elevation semi-deciduous forest: ~1,200 m a.s.l.) in southern Ecuador to calculate relative growth rate (RGR) based on stem diameter for all living stems over a two-year census interval. We combined functional traits of leaves (i.e., foliar nitrogen and phosphorus concentrations, leaf thickness, leaf toughness, specific leaf area) and stems (i.e., bark thickness, wood specific gravity, vessel density, vessel diameter, hydraulic conductivity) with soil chemistry data (phosphorus availability, carbon: nitrogen ratio and others) to build predictive models of tree growth. At both elevations, RGR declined strongly with increasing tree size, indicating a consistent size-dependent constraint on RGR. Functional traits emerged as significant predictors of RGR, with growth increasing in association with acquisitive traits and decreasing with conservative traits. In particular, high wood specific gravity (WSG) was negatively associated with RGR, consistent with species adopting conservative strategies characterized by greater investment in structural integrity and hydraulic safety at the expense of rapid growth. Soil properties showed only weak and inconsistent associations with RGR. Model comparisons confirmed that tree size and functional traits, notably WSG, explained substantially more variation in RGR than soil variables, while models including additional predictors did not improve model performance. Our findings highlight the dominant role of species functional strategies and tree size in explaining variation in tree growth in tropical dry forests.
Camptotheca acuminata Dence. (C. acuminata) is an endemic tree species in China with considerable ornamental and medicinal importance. Mixed planting of C. acuminata with compatible tree species helps enhance stand stability and supports the sustainable restoration of C. acuminata resources. This study performed field experiments to make a comparison between pure forest and mixed forest of C. acuminata and Taxus chinensis var. mairei in terms of tree growth performance, photosynthetic physiological characteristics, soil physicochemical properties, and rhizosphere microbial communities. Mixed planting significantly promoted growth: the five-year average tree height and diameter at breast height (DBH) of C. acuminata were 15.05 and 9.24% higher in mixed stands than in pure stands (p < 0.05), respectively. During the growing season, the monthly net Photosynth etic rate of C. acuminata leaves in mixed stands was consistently higher than that in pure stands. In addition, mixed planting increased soil total nitrogen by 48.33% and obviously elevated the contents of soil organic carbon, available phosphorus, and available potassium (p < 0.05). Mixed planting also significantly improved the diversity of soil bacterial and fungal communities, enriched the nutrient-mineralizing phyla Proteobacteria and Ascomycota, and reduced the abundance of oligotrophic Acidobacteria. The optimized rhizosphere microbial community improved soil nutrient availability, further enhanced leaf photosynthetic capacity, and ultimately promoted the growth of C. acuminata. This study provides valuable insights for improving the reforestation and plantation management strategies for wild C. acuminata.
IntroductionStreet greenery contributes to urban environmental quality and everyday pedestrian experience, but its value cannot be fully described by a single greenness index. This study examines how layered street greenery varies with road-network position and perceived streetscape quality in Beijing.MethodsWe developed a road-segment-level framework that integrates a network-derived road hierarchy, street-view-based vegetation segmentation, image-based perception indicators, and explainable machine learning. The hierarchy was constructed from road-network indicators and PCA-based grouping rather than official road classifications. Visible tree, bush, and grass shares were quantified from street-view imagery, and Bayesian-optimized XGBoost with SHAP was used to examine associations with road-network, geometric, accessibility, and perceived streetscape variables.ResultsThe Tree-Bush-Grass visible-composition type was dominant across the network (53.06% in Level 1, 58.53% in Level 2, and 56.30% in Level 3), whereas secondary visible-composition types varied across road-network levels. The Tree-Bush type increased toward locally serving streets, while the Tree-Grass type declined. Within comparable visible-composition clusters, median tree shares also increased from Level 1 to Level 3. Attribution results indicated level-specific associations: network, and geometric variables were more prominent for higher-order roads, whereas perception-related variables became more visible for lower-order streets.DiscussionLayered street greenery in Beijing is associated with both network position and local streetscape conditions. These associations are not interpreted as causal explanations; instead, they support hierarchy-sensitive greening strategies that distinguish corridor-scale continuity from more flexible, local, perception-oriented planting contexts.
BackgroundAtmospheric nitrogen (N) deposition can strongly alter soil organic carbon (SOC) stabilization by regulating microbial-derived carbon (C) formation. Microbial necromass carbon (MNC) and glomalin-related soil protein (GRSP) are important contributors to SOC persistence, yet how long-term N enrichment affects these microbial-derived C pools and their microbial drivers across soil depths remains unclear in alpine forest ecosystems.MethodsWe investigated the effects of six-year N addition on bacterial necromass C (BNC), fungal necromass C (FNC), MNC, total GRSP (T-GRSP), their SOC-normalized proportions, and associated soil and microbial mechanisms in an alpine coniferous forest on the southeastern Xizang Plateau. Four N addition treatments—control, low N, medium N, and high N addition—were established, and soils were collected from the 0–20 and 20–40 cm layers. Random forest analysis, bacterial–fungal co-occurrence networks, and microbial module analysis were used to identify variables associated with microbial-derived C accumulation.ResultsLow and medium N addition increased BNC, FNC, MNC, and T-GRSP, whereas these positive effects were weakened under high N addition. Although microbial-derived C contents were consistently higher in surface soil, the SOC-normalized contribution of microbial necromass responded more strongly to N addition in the 20–40 cm layer, while T-GRSP:SOC remained relatively stable across treatments and depths. Random forest analysis suggested that soil pH, nutrient availability, and C:N:P stoichiometry were closely associated with MNC and T-GRSP variation, with additional associations involving enzyme activities, microbial diversity, and community composition, particularly in deeper soil. Exploratory depth-specific bacterial–fungal co-occurrence networks indicated fewer associations and a higher proportion of negative links in deeper soil. Module analysis further identified specific bacterial and fungal modules associated with SOC fractions, microbial necromass, and GRSP-related indicators.ConclusionModerate N enrichment was associated with greater microbial-derived C accumulation, whereas high ammonium-sulfate N addition showed weaker positive effects accompanied by nutrient imbalance, soil acidification, and altered microbial attributes. These findings highlight the importance of integrating microbial residues, GRSP, soil nutrient stoichiometry, and microbial co-occurrence patterns when assessing SOC stabilization under increasing N deposition.
The forest bioeconomy is increasingly discussed as a policy and development concept, yet its meaning, implementation pathways, and societal acceptance remain uneven across different contexts. While bioeconomy transitions have been widely examined in the Global North, less attention has been paid to stakeholder perceptions in areas with different economic, institutional, and policy conditions. This study examines perceptions of the forest bioeconomy across cases in Central Europe and the Mekong region, focusing on three dimensions: understanding of bioeconomy-related concepts and sectors, perceptions of implementation and forest-based industrial transition, and views on support mechanisms and barriers. Data were collected through an online questionnaire survey and statistical analyses, including descriptive statistics, chi-square and Fisher’s exact tests, cluster analysis, and binary logistic regression. The results show that the term “bioeconomy” was less well understood than related concepts such as “sustainable forest management” (SFM) and “circular economy”, suggesting that awareness-raising efforts could build on concepts already familiar to stakeholders. The analysis also reveals differences between the Central Europe and the Mekong cases in terms of perceptions of bioeconomy concepts, opportunities, and barriers to implementation. At the same time, stakeholders across the studied cases showed broad agreement on the importance of forest-based sectors for bioeconomy development. The inclusion of cases from Central Europe and the Mekong region allows for an exploratory comparison of stakeholder perspectives across different cultural, economic, and policy settings. By bringing together these diverse contexts, the study contributes to filling knowledge gaps in less-represented regions and points to possible pathways for cross-regional cooperation, and knowledge exchange in support of forest bioeconomy development.
