Wildfires are an increasingly important factor in boreal forest biome. The fire cycle have significant effects on the cycling of nutrients within and through an ecosystem. Past research shows that major elements, nutrients, and organic matter in stream water can be altered for decades after a wildfire. Here we examine how stream chemistry might be used to characterize biogeochemical effects of fire across the continuous permafrost taiga of the Central Siberia. By comparing the results of laboratory combustion of organic horizons, soil solution chemistry in burned and unburned watersheds, and stream chemistry in a chronosequence of watersheds with a well-described fire history, we assess possible proxies in stream water chemistry for wildfire severity and timing in this landscape. Our results suggest that the time since last wildfire can be estimated by sulfates (SO 4 2− ) and nitrates (NO 3 − ) concentrations, and that the soil active layer thickness (ALT, the soil depth at which soil thaws annually) increase by wildfires is reflected in bicarbonates (HCO 3 − ) concentrations. Phosphate (PO 4 3− ), although it is released from organic matter by combustion, is unchanged in stream water following fire. Chloride (Cl − ) produces a useful marker for hydrologic conditions at the time of sampling, allowing a relatively small number of stream water samples to be used to characterize past fire regime. Concentrations of SO 4 2− , NO 3 − and HCO 3 − in stream runoff can thus be used as a specific fingerprint of fire history in the northern taiga larch and birch forests of the Central Siberia, since an increase in their concentrations in stream runoff reflects fire occurrence in the catchment area. • Wildfires increase concentrations of major ions in pyrogenic organic layers, topsoil and streams. • Phosphorus is liberated by organic matter combustion, but retained in subsoil. • Wildfires affect stream HCO 3 − , SO 4 2− , Cl − and NO 3 − concentrations at decadal scales. • Stream bicarbonate can serve as a proxy for the active layer depth and wildfire timing • Sulfate in stream water is the most reliable indicator of time since fire disturbance in the catchments.

Forest soil organic carbon (SOC) accumulation is regulated by plant-derived carbon inputs and soil environmental conditions, but the relative roles of litter composition and soil physicochemical properties in regulating SOC fractions remain unclear in high-elevation forest ecosystems. This study aimed to determine whether variation in SOC among different forest types was mainly associated with particulate organic carbon (POC) or mineral-associated organic carbon (MAOC), and to identify the relative roles of litter characteristics, soil physicochemical properties, microbial biomass, and enzyme activities in regulating SOC fractions. Four forest types on the eastern edge of the Tibetan Plateau were investigated: broadleaved poplar forest (PLF), larch forest (LXF), seabuckthorn forest (SBF), and Dasiphora shrubland (DS). PLF had the highest SOC and POC contents (75.8 and 48.5 g kg−1, respectively), whereas MAOC did not differ significantly among forest types. SOC was strongly positively correlated with POC (R2 = 0.74, p < 0.001), but not with MAOC, indicating that SOC variation was mainly associated with POC accumulation. PLF litter contained higher labile and recalcitrant carbon components, including soluble sugar (19.9 g kg−1), starch (30.1 g kg−1), lignin (94.6 g kg−1), and litter carbon (404 g kg−1). Partial least squares path modeling showed that soil physicochemical properties had the strongest direct path relationship with SOC variation (p < 0.001), while litter composition was positively associated with microbial biomass and POC formation (p < 0.01). These findings suggest that POC formation was the main fraction-level feature associated with SOC accumulation, while soil properties and litter composition were related to SOC through different pathways.

ABSTRACT This study investigated forest edge areas adjacent to a residential road in a hilly area of Nagano prefecture, Japan, to examine the impact of Cervus nippon (hereafter referred to as “deer”) movements on physical erosion and changes in infiltration capacity of forest soils. The survey area included the edges of cypress and larch forests bordering a residential road west of the Mochizuki ranch in Mochizuki-machi, Saku city, Nagano prefecture. Soil erosion was assessed by measuring the height and direction of exposed roots at multiple points. Analysis of root system exposure height (Rh) revealed higher values in the larch forest than in the Japanese cypress forest. Furthermore, the polar coordinate distribution of exposed roots indicated predominant exposure in the steepest slope direction, with some deviations, suggesting that slope angle influences deer movement patterns. Comparisons of cumulative infiltration capacity showed lower values in the cypress forest compared to the larch forest. Soil with clear deer hoof prints exhibited lower infiltration capacity in both areas. The unsaturated hydraulic conductivity (K) for disturbed soil along the deer migration route was approximately half that for undegraded soil, and in soil with clear deer hoof prints, it decreased to about 10% that for undegraded soil.

ABSTRACT Recent frequent heatwaves have adversely affected the carbon cycles of terrestrial ecosystems. Solar‐induced chlorophyll fluorescence (SIF) and the photochemical reflectance index (PRI) can detect heat and drought stress in vegetation. However, the applicability of these indicators in extreme cases, such as heatwaves, needs consideration. We examined diurnal changes observed in tower‐based SIF, PRI, canopy conductance, and gross primary productivity (GPP) over 3 weeks during mid‐summer in 2022 in a cool‐temperate deciduous forest covered by Larix kaempferi (Lamb.) Carrière, in Japan. We found that half‐hourly GPP and SIF declined significantly from noon to afternoon during the latter part of clear, extremely hot days (up to 31°C) when the soil water content (SWC) was low (&lt; 21%), and the vapor pressure deficit (VPD) was high (&gt; 15 hPa). Values of GPP and SIF peaked at 21.7°C and 26.8°C, respectively, and they declined at higher temperatures. Canopy conductance declined with increasing air temperature and VPD, suggesting that stomatal closure caused the observed reduction in GPP. To investigate the stress response without light‐dependent variations, canopy fluorescence emission efficiency ( εF ) and light use efficiency (LUE) were calculated from SIF and GPP, respectively. VPD had the most significant negative correlation with PRI, LUE, and εF . εF was also associated with SWC, particularly under lower SWC conditions. Our results demonstrate that SIF and PRI responded to heat and drought with different sensitivities and thresholds and can serve as diagnostic tools to assess the influence of moderate to extreme environments on terrestrial ecosystems.

Evaporation dominates growing season evapotranspiration: A case study from a boreal larch forest with synchronized water supply and energy demand in China

Erannis ankeraria (Staudinger) (Lepidoptera: Geometridae) is a defoliator of Larix, Quercus, and Picea trees. Recent outbreaks of this pest have caused extensive damage to the larch forests in north-eastern China RESULTS: Through gas chromatography-electroantennographic detection (GC-EAD) and gas chromatography-mass spectrometry (GC-MS), Z3Z6Z9-19:Hy, Z3Z9-cis-6,7-epo-19:Hy, Z6Z9-cis-3,4-epo-19:Hy, and Z3Z6-cis-9,10-epo-19:Hy were identified from sex pheromone glands of Erannis ankeraria females. The quaternary mixture of these synthetic pheromone components at a ratio of 1:0.5:1.2:1.3 achieved the optimal trapping effect in field experiments. Biotransformation and activity assays revealed that Z3Z6Z9-19:Hy serves as a precursor of epoxynonadecadienes, regulates the upwind flight behavior of male moths, and exhibits a synergistic effect with the epoxy pheromone components. Notably, the 3,4- and 9,10-epoxides, newly identified in the genus Erannis, both markedly decrease the captures of Colotois pennaria (Lepidoptera: Geometridae) CONCLUSIONS: The sex pheromone of Erannis ankeraria was identified as a quaternary blend, which exhibits a remarkable efficacy in attracting Erannis ankeraria males, thereby offering a reliable tool for population monitoring. Z3Z6Z9-19:Hy acts as a precursor in the biosynthesis of three epoxynonadecadiene pheromone components, and is also a critical synergistic pheromone component. The 3,4- and 9,10-epoxides likely mediate interspecific chemical communication between Erannis ankeraria and C. pennaria, enabling species-specific recognition and reproductive isolation © 2025 Society of Chemical Industry.

Mountain herbivores are a multispecies group of animals with behavioural adaptations to the severe living conditions at high elevations. Because of their marked seasonality, mountain ecosystems are particularly sensitive to the impact of long-term meteorological changes. These changes can significantly influence the abundance, distribution, and ultimately the survival of plant and animal species. We focused on the spatial behaviour of a herd of 21 radio-tagged female chamois, Rupicapra rupicapra , from December 1998 through November 2001. We investigated home range size, habitat selection and elevational distribution of female chamois. Our findings revealed distinct seasonal patterns in home range size, with smaller ranges observed during the warmer months (May-October), as well as high interindividual variability in female spatial behaviour, with more than 80% variability in home range size explained by the individual identity. Home range size also decreased with increasing elevations, but only during the warmer months. Sparse larch forests were selected as preferred habitats, shrublands and other coniferous forests were avoided, and grasslands were used proportionally to availability. Chamois were counted yearly in 2000–2001 and from 2020 to 2023 using the same methodology, with a mean temperature increase of ∼2 °C. Counts revealed an upward shift of up to ∼90 m in the summer locations of most females, although a minority of groups remained stationary or even moved downwards. Although predation and interspecific competition may have played ancillary roles, alteration in vegetation distribution, and in turn, local food availability, was probably the major factor triggering chamois movements. Contrary to predictions, despite belonging to the same female herd, some individuals showed different spatial behaviour responses, which could be adaptive to ensure survival in case of a changing environmental context, as natural selection can only take place if there is individual variation. • Female chamois home range size varied seasonally, with high individual variability. • Sparse larch forests were preferred; other conifers and shrublands were avoided. • In summer, females shifted ∼90 m upslope over 20 years, as temperatures rose by ∼2 °C. • Yet, 10.6% of female groups remained stationary or moved downwards. • Thermal anomaly affects space use, but individual response variance ensures survival.

Abstract Root resistance is a key factor in determining the risk of wind damage through uprooting. To date, the influence of soil type on root resistance has primarily been assessed using the critical turning moment derived from tree-pulling experiments. However, for effective forest risk management, this influence should be evaluated based on cumulative wind damage risk. In this study, we assessed the cumulative wind damage risk for Japanese larch [Larix kaempferi (Lamb.) Carrière] at two sites with different soil types—brown forest soil and andosol—in Hokkaido, northern Japan. Our approach combined pulling experiments, a mechanistic model, and exceedance probability calculations. The pulling experiments showed a 13% greater critical turning moment for brown forest soil than that for andosol. This difference translated to a critical wind speed difference of ~1 m/s (5.5%–6.4%), as indicated by the mechanistic model. In contrast, the exceedance probability calculations revealed a much larger disparity: the cumulative risk throughout the silvicultural cycle of Japanese larch was 2.7-fold higher for andosol than that for brown forest soil. These findings highlight that soil type effects are magnified when cumulative risk is estimated using the critical turning moment.

Soil nematode communities in the subcrown space of Siberian larch Larix sibirica Ledeb., both cultivated in botanical gardens and growing in natural forests were studied and compared between each other. The results exhibited significant variations in total nematode abundance at all locations, with both extremely low and high values. The taxonomic diversity of nematodes was higher in the soil under larch in natural forests compared to that in botanical gardens. The larch forest within its range (Altai Republic) distinguished by the high taxonomic diversity of nematodes and highest number of specific taxa (nine genera vs. one to three at other points) among all locations. An increase in the relative abundance of plant parasites in the soil under trees cultivated in botanical gardens, as well as nematodes associated with plants under naturally growing larch, were observed in the ecotrophic structure of nematode communities. The evaluation of ecological indices (SI and EI) revealed the presence of transformed soil ecosystems in the subcrown space of larch trees cultivated in botanical gardens. Also, a statistically significant relationship between soil pH and the nematode community maturity index was found. Thus, the patterns obtained can be explained by both the anthropogenic impact on ecosystems associated with tree cultivation activities in botanical gardens and a complex of natural factors (climatic, edaphic, phytocenotic) operating at the investigated sites.

Abstract Background Experimental forests present unrivaled opportunities to understand the factors influencing vegetation structure many decades after silvicultural treatments or natural disturbances. In this study, we use the western larch-dominated moist mixed-conifer forests at Miller Creek Demonstration Forest (Miller Creek) to better understand the relationship between current vegetation structure, 55 years after two forms of high-intensity disturbance (clearcutting plus broadcast burning, and a high-severity wildfire) and characteristics of the site, the disturbance, and pre-disturbance vegetation. We also utilize measurements of fire intensity to test the hypothesis that moderate intensity fires promote greater fine-scale vegetation spatial heterogeneity, many decades disturbance, than low or high fire intensities. Results Fifty-five years after high-intensity disturbance, forest cover has returned to all sample sites at Miller Creek. Further, these sites support the full suite of tree species common to this forest type; although western larch is generally dominant in the overstory, its more shade-tolerant associates are abundant in the understory. Our results suggest that fire intensity and heat load index, used as summaries of disturbance and site characteristics, respectively, are associated with current overstory vegetation. By contrast, our data implies that understory vegetation at Miller Creek is more strongly influenced by a variety of site factors. Our results provide no evidence of a relationship between fire intensity and spatial heterogeneity. Conclusions Our findings suggest that characteristics of both the initiating disturbance and the site influence vegetation structure at Miller Creek. Moreover, five-plus decades post-disturbance, the understory plant community is more closely aligned with habitat type than is the overstory. However, while western larch is likely to maintain overstory dominance at Miller Creek for many decades, our findings suggest that perpetuating this species alongside a diverse understory may call for future moderate- to high-intensity harvests with overstory retention and broadcast burning.

Wildfires alter multiple soil functions in forest ecosystems, but how they reconfigure the linkages between these functions is not fully understood. We evaluated the 1-year-postfire and 11-year-postfire effects of wildfire on carbon sequestration, nutrient cycling, fertility maintenance, and erosion regulation, as well as their relationships, in a Chinese boreal larch forest. We further identified the environmental drivers regulating these associations. One year postfire, the soil fertility index transiently increased by 85%, whereas the carbon sequestration and nutrient cycling declined by 58% and 54%, respectively. Principal component analysis showed that wildfire decoupled the multivariate relationships between four soil functions. While these functions were closely clustered in unburned controls, they became dispersed one year postfire, indicating functional dissociation. After eleven years of recovery, a partial reassembly occurred, but with a reconfigured functional structure distinct from the pre-fire state. For the functional pairs, the impact of wildfire was limited to shifting the relationship between the soil fertility and nutrient cycling from a non-significant negative correlation to a significant positive correlation. Redundancy analysis showed that the soil water content remained the primary environmental driver of soil functional relationships before and after the fire, but its role reversed from negative in unburned stands to positive during the postfire recovery, suggesting a shift toward water-mediated functional coupling. Wildfires in boreal forests have far-reaching effects on soil ecosystems, including impacts on the relationships between various soil functions. Our results indicate that wildfire reconfigures the network of soil function linkages in boreal forests, with implications for the recovery of boreal soil ecosystems.

Accurate leaf area density (LAD) is essential for radiative transfer simulations of forests, yet measurement methods are often limited to terrestrial LiDAR scanning (TLS). Numerous measurements are required to minimize occlusion; however, upper-canopy measurements are insufficient. Recently, new measurement methods such as handheld LiDAR scanning (HLS) and UAV-LiDAR have demonstrated the potential to reduce occlusion by enabling mobile data collection. However, the data acquired by UAV-LiDAR and HLS have not been directly used for radiative transfer calculations because their measurement accuracy is inferior to that of TLS, primarily because of the limitations of the inertial monitoring unit accuracy. The aim of this paper is to propose a radiance simulation model that considers the attenuation and reflection of direct irradiance within a forest canopy, utilizing LiDAR measurements. In the proposed approach, the point cloud is first converted into voxels. Then, the attenuation of the irradiance reaching an arbitrary voxel was calculated using the Beer-Lambert law with the point cloud between the light source and voxel as the input value. Finally, the radiance reflected in the direction of the sensor was calculated. The proposed method was applied to point clouds of a larch forest obtained through UAV-LiDAR and HLS, as well as to a combined dataset. The reliability of the proposed method was evaluated using the correlation coefficient (r) for the Sentinel-2 top of the atmosphere product red band reflectance. The results indicated that the r calculated from the radiance based on the UAV-LiDAR and coupled point cloud exceeded 0.75, indicating the validity of the method.

Mapping aboveground tree biomass and uncertainty using an upscaling approach: A case study of the larch forests in northeastern China using UAV laser scanning data

The features of post-pyrogenic successions in green moss and green moss-dwarf shrub larch forests of Larix cajanderi in the southern part of Magadan Oblast are considered. The materials of the stageby-stage vegetation restoration in one of the burnt-out areas of the Dukcha River valley during the first ten vegetation seasons from the day of the fire are presented. The dependence of succession processes on the structural and functional organization of the larch phytocenosis, the preservation of the forest stand, and the developing ecological conditions in the burnt-out area is discussed. A distinctive feature of the studied burnt-out area is the powerful growth of Carex globularis in areas with dead larches, in contrast to the restoration of the lower tiers through the development of mosses of the genus Polytrichum, which is usually observed in burnt-out areas.

Icings are cryospheric features that exert a significant influence on natural ecosystems and engineering infrastructure. Particular interest is drawn to icings located within forested areas, as trees can respond to their impacts, recording information about the dynamics of icing processes in their growth rings. This study focuses on mapping forest stands within icing-affected zones to identify promising areas for future dendrochronological investigations of icing processes in the transboundary Selenga River Basin. For the purpose of icing mapping, the study employed medium-resolution satellite remote sensing data (Landsat-8, Sentinel-2, Kanopus-V). To assess the presence of forest vegetation within icing zones, three global canopy height products were utilized: ETH (based on Sentinel-2 and GEDI), GFCH (based on Landsat and GEDI), and GCHM (an AI-based model derived from satellite imagery). The analysis revealed that approximately 65 % of the mapped icings are covered by forest vegetation. These forested icings are predominantly located in the Russian part of the basin, particularly on mountain slopes, where larch and cedar-fir forests are dominant. In contrast, forested icings are significantly less common in the Mongolian part of the basin and are mainly represented by sparse larch stands. At a key site a high-resolution digital elevation model with 0.1 m accuracy was created based on UAV-based aerial photography. This dataset was used to validate the global canopy height models. Comparative analysis at the test site demonstrated that global models tend to overestimate tree heights when compared to values derived from UAV. As expected, the model with the higher spatial resolution more accurately represented the horizontal structure of the forest canopy, though it still exhibited substantial height inaccuracies. Nevertheless, these global models proved useful for identifying areas containing trees that are potentially suitable for dendrochronological analysis. Thus, the spatial database of forested icing zones developed in this study can serve as a foundation for planning the collection of tree-ring samples and conducting further dendrochronological research on icing processes throughout the Selenga River Basin.

Aim of study: To evaluate the effectiveness of distance-dependent indices in characterizing deadwood diversity at stand level. Area of study: Four forest types in the Italian Alps (Trentino Alto Adige region): Norway spruce, mixed Silver fir–Norway spruce, European larch, and European beech forests. Materials and methods: Distance-dependent indices from the literature, originally developed to assess stand structure, were applied to evaluate deadwood diversity in four forest stands (40 sample plots). The performance was assessed by comparing the “structural group of four” method, which considers the four deadwood elements closest to the plot center, with the fixed-area sampling method, which includes all deadwood elements in the plot (531 m2). Main results: The results showed an average deadwood volume of 18.65 m³ ha-1 and a higher deadwood diversity by species, decay class and size for European beech forests than the other three forest types. The non-parametric Wilcoxon signed rank test showed no statistically significant difference in the indices calculated using the three and five closest deadwood elements compared to all elements in the plots. Research highlights: Distance-dependent spatial indices proved effective for characterizing deadwood diversity at the stand level. The “structural group of four” sampling method proved to be the most efficient, as including additional elements beyond four did not significantly improve accuracy. This approach represents a reliable and time-efficient tool for assessing deadwood diversity.

Abstract The Hengduan Mountains, a biodiversity hotspot on the Tibetan Plateau, are undergoing rapid elevation-dependent warming, profoundly altering alpine forest dynamics. Larix species in this region dominate high-altitude treelines and represent the world’s lowest-latitude natural populations of larch forests. However, climate-growth relationships of Larix species at the whole regional scales have received little attention. To address this gap, we investigated the spatiotemporal variability of radial growth in Larix species and their climatic sensitivity across this region using a network of 26 tree-ring chronologies spanning 1960–2022. Hierarchical clustering identified three distinct geographical clusters (southwestern, central, and northeastern), revealing divergent growth trajectories and climate responses. Results demonstrated that growing-season temperature was the primary climatic driver of Larix radial growth, but its influence varied spatially: southwestern populations correlate strongly with May–August mean temperatures, central populations with May–August mean temperatures, and northeastern populations with April–June maximum temperatures. Each cluster exhibited unique growth trends and thermal sensitivities before and after the rapid warming since 1990. Meanwhile, an inter-individual response divergence became apparent under warming, reflecting intensified competition and microhabitat-scale stress, which highlights the limitations of traditional population-level climate response models that assume a uniform response. Spatial heterogeneity in climate-growth relationships reflected synergistic thermal-hydrological effects and species-specific adaptations, with warming enhancing carbon sequestration in moisture-sufficient areas but threatening high-elevation ecosystems through growth suppression and treelines instability. These findings underscore the need for regionally tailored conservation strategies to address climate-driven ecological imbalances in alpine forests.

Accurately quantifying forest volume and identifying its driving mechanisms are critical for achieving carbon neutrality objectives. Using data from the National Forest Inventory (NFI), plot-level measurements, and environmental variables from pure larch (LP), birch (BP), and mixed larch-birch (LB) forests in the mountainous region of northern Hebei, China, this study employed random forest (RF) algorithms to evaluate the relative importance and partial dependence of biotic and abiotic factors on stand volume growth. A total of 33 predictors related to climate, topography, and soil were analyzed, and model hyperparameters were optimized through grid search combined with blocked cross-validation to mitigate spatial autocorrelation. The RF models exhibited strong predictive performance, with the BP model achieving the highest R² (0.92). The minimum temperature of the coldest month (Bio12) was identified as the most influential predictor across all stand types, while stand age also exerted a substantial effect on growth dynamics. Young and middle-aged forests demonstrated higher productivity compared with near-mature and mature stands, suggesting that the latter require improved management interventions to sustain growth. The LB stands exhibited higher productivity than pure stands, likely due to species complementarity and interspecific facilitation. In LP, growth was primarily driven by the interaction between stand age and canopy density, whereas in BP, slope position was more decisive. The management of LB stands offers potential to maintain or enhance forest productivity. The findings emphasize the importance of adaptive forest management strategies that optimize forest structure and mitigate climate change impacts. These insights contribute to advancing carbon sequestration efforts and supporting the development of carbon neutrality policies by enhancing forest productivity and resilience to climate variability.

Abstract Korea has achieved rapid forest recovery since the 1970s through large-scale afforestation programs and effective policies. Larch ( Larix kaempferi ) is regarded as a key forest species in Korea owing to its rapid growth, adaptability to varied conditions, and superior timber properties, leading to its extensive use in construction and structural applications. However, quantitative information on the availability of larch resources and their capacity to meet projected domestic demand is limited. This study analyzed the stock volume and growth of over-30-year-old larch forests in Korea and predicted the resource depletion under long-term demand scenarios. Geographic information systems and national forest inventory data were used to estimate average stand volume and periodic growth by age class. Cumulative growth was then projected at 5-year intervals. To assess demand, three scenarios (baseline, lower, and upper) were developed using the autoregressive integrated moving average (ARIMA) forecasting model, projected to 2060, to estimate the remaining volume of larch resources over time. The results show resources are projected to be depleted by approximately 2045 under the baseline, 2040 under the upper-demand, and 2055 under the lower-demand scenarios, as cumulative demand eventually surpasses the available growth volume. Although expanding reforestation efforts and inducing new entries into maturing stands could delay depletion, structural adjustments in demand and the development of substitute species are also needed to ensure long-term supply stability. This study provides one of the first quantitative, resource-based assessments of larch sustainability in Korea and offers insights for strategies on forest resource circulation and utilization.

Ground surface temperature variations and their links to permafrost distribution in the Genhe River Basin, Da Xing'anling Mountain Range