Forests

Landslides cause significant disturbances to mountainous ecosystems and human activities. Due to climate change, the frequency of landslides as secondary disasters has notably increased compared to the past. Further exploration is needed to understand the effects of different restoration methods on post-landslide plant communities and soil properties over different periods of time. In this regard, we selected Lantian County in the northern foothills of the Qinling Mountains as our study area. We conducted surveys on artificially restored and naturally recovered plots at 1, 6, and 11 years after landslide events. Undamaged areas were chosen nearby as control plots. We identified vegetation types and species diversity after artificial and natural recovery and further analyzed the impact of different restoration strategies on vegetation patterns and soil properties. The research results indicate that, compared with natural recovery, artificial restoration can more quickly improve vegetation and soil. With the increasing time gradient, the average ground cover of the herbaceous layer in natural recovery decreased gradually from 47% at year one to 34% at year eleven. In contrast, in artificial restoration, the average ground cover of the herbaceous layer increased from 27% at year one to 44% at year eleven. For the shrub layer, in natural recovery, the average ground cover gradually increased to 39% over eleven years. While in artificial restoration, the average ground cover for the shrub layer gradually increased to 46% over the same period. In the artificial restoration plots, soil pH gradually increased (from 6.2 to 8.2), while TN content gradually decreased (from 1.7 g/kg to 0.9 g/kg). Similarly, TK content decreased (from 22.4 g/kg to 14.5 g/kg), and AP content showed a decreasing trend (from 20.7 mg/kg to 11.4 mg/kg). In the natural recovery plots, DNA content gradually increased (from 3.2 μg/g/d to 142.6 μg/g/d), and SC content gradually increased as well (from 2.4 mg/d/g to 23.1 mg/d/g). In contrast, on sites undergoing natural recovery, the short-term restoration rates of vegetation and soil are lower, but they show greater stability over a longer time. This study provides a new perspective on vegetation restoration strategies and is expected to offer insights for the optimization of post-landslide recovery in the future. Full article

Scent is the key character of the horticultural ornamental plant rose, and benzenoid–phenylpropanoid compounds are the main source of scent. However, the underlying biosynthesis mechanism of these benzenoid–phenylpropanoid scent metabolites during Rosa flowering is poorly understood. In this study, the volatile metabolome and transcriptome conjoint analysis was conducted on the six stages petals of the variety ‘Lanxing’ to investigate the synthesis of benzenoid–phenylpropanoid metabolites. A total of 25 benzenoid–phenylpropanoid volatile compounds were identified, of which eugenol possessed the highest content. Meanwhile, transcriptome analysis produced 87.9 million clean reads and 22,004 differentially expressed genes (DEGs). Group pairwise comparison of gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis found DEGs were enriched into phenylpropanoid compound synthesis related pathway. Weighted gene co-expression network analysis (WGCNA) found a MEgreenyellow gene module (650 DEGs) correlated with phenylpropanoid compounds. Based on the eugenol content variation and gene spatio-temporal expression, a key candidate gene RcEGS32 related to the synthesis of eugenol was identified. Co-expression network analysis found that five transcription factors, RcMYB1, RcBES1, RcERF2, RcbHLH1, and RcTUB, may act as regulators in the eugenol synthesis process by directly binding to RcEGS32 or forming a complex unit. This study provided key insights into the formation of the scent substance eugenol during flowering, offering a valuable volatile metabolome and transcriptome resource for the future target trait-related gene discovery of roses. Full article

The timber degradation and overexploitation of Tilia amurensis necessitate strategic genetic resource management. This study presents a comprehensive approach to plus-tree selection, focusing on growth evaluation. Drawing from the procedures developed for evergreen oak, it encompasses base population selection, criteria establishment, forest stand investigation, standardized measurements, and tree selection. This study advances the baseline selection methods by emphasizing growth differentiation through age and environmental adjustments. A total of 62 superior individuals were selected from 176 candidates across 20 populations, effectively expanding the geographical boundaries. This growth-centric improved approach offers practical insights for selective breeding and genetic conservation, and addresses the ecological characteristics of the species. This study underscores the need for further exploration of genetic differentiation and biological traits to provide a foundation for refining T. amurensis tree improvement programs. In a broader context, these findings contribute to the understanding and sustainable management of diverse broadleaf forests. Full article

Creep performance is a crucial factor that must be considered in structural design. This paper aims to investigate the creep failure mode, creep strain, creep compliance, and other creep properties of bamboo scrimber under long-term tension in parallel-to-grain. To establish a general creep life prediction method for the full stress level of the bamboo scrimber, a multi-branch Kelvin–Voigt model, a generalized Maxwell model, and a creep finite element simulation were employed. The results showed that the creep strain curve of bamboo scrimber included the unsteady creep stage and the stable creep stage, but not the accelerated creep stage. When the stress ratio was less than 0.3, the residual strength decreased gradually. Below 70% of the ultimate load capacity, the creep characteristics of the bamboo scrimber were linear viscoelastic, and the creep compliance was generally independent of the load level. The creep finite element model of bamboo scrimber could accurately calculate the creep deformation of specimens. Based on this creep finite element model and creep failure rules, a life prediction model for the full stress level of bamboo scrimber was established, which could accurately predict the creep life. This paper provides theoretical guidance for the creep design of bamboo scrimber in engineering structures. Full article

In recent years, accurate estimation and spatial mapping of above-ground carbon (AGC) storage in forests have been crucial for formulating carbon trading policies and promoting sustainable development strategies. Forest structure complexities mean that during their growth, trees may be affected by the surrounding environment, giving rise to spatial autocorrelation and heterogeneity in nearby forest segments. When estimating forest AGC through remote sensing, data saturation can arise in dense forest stands, adding to the uncertainties in AGC estimation. Our study used field-measured stand factors data from 138 forest fire risk plots located in Fenglin County in the Northeastern region, set within a series of temperate forest environments in 2021 and Sentinel-2 remote sensing image data with a spatial resolution of 10 m. Using ordinary least squares (OLS) as a baseline, we constructed and compared it against four spatial regression models, spatial lag model (SLM), spatial error model (SEM), spatial Durbin model (SDM), and geographically weighted regression (GWR), to better understand forest AGC spatial distribution. The results of local spatial analysis reveal significant spatial effects among plot data. The GWR model outperformed others with an R² value of 0.695 and the lowest rRMSE at 0.273, considering spatial heterogeneity and extending the threshold range for AGC estimation. To address the challenge of light saturation during AGC estimation, we deployed traditional linear functions, the generalized additive model (GAM), and the quantile generalized additive model (QGAM). AGC light saturation values derived from QGAM most accurately reflect the actual conditions, with the forests in Fenglin County exhibiting a light saturation range of 108.832 to 129.894 Mg/ha. The GWR effectively alleviated the impact of data saturation, thereby reducing the uncertainty of AGC spatial distribution in Fenglin County. Overall, accurate predictions of large-scale forest carbon storage provide valuable guidance for forest management, forest conservation, and the promotion of sustainable development strategies. Full article

In the context of a changing environment, understanding the interaction between vegetation and climate is crucial for assessing, predicting, and adapting to future changes in different vegetation types. Vegetation exhibits high sensitivity to external environmental factors, making this understanding particularly significant. This study utilizes geospatial analysis techniques, such as geographic information systems, to investigate vegetation dynamics based on remote sensing data and climatic variables, including annual air temperature, annual precipitation, and annual solar radiation. The research methodology encompasses data collection, processing, and analysis, incorporating multispectral imagery and multilayered maps of various parameters. The calculation of the normalized difference vegetation index serves to evaluate changes in vegetation cover, identify areas experiencing variations in green biomass, and establish strategies for the future development of different vegetation types. During the period from 2001 to 2022, the average normalized difference vegetation index value in the Southeastern Crimea region amounted to 0.443. The highest average values were recorded in the year 2006, reaching a magnitude of 0.469. Conversely, the lowest values were observed in the years 2001–2002, constituting 0.397. It has been ascertained that an overarching positive trend in the evolution of NDVI values from 2001 to 2022 is apparent, thus implying a notable augmentation in vegetative biomass. However, adversarial trends manifest in discrete locales adjacent to the cities of Sudak and Feodosia, along with the coastal stretches of the Black Sea. Correlation analysis is employed to establish relationships between vegetation changes and climatic indicators. The findings contribute to our understanding of the vulnerability of various vegetation types and ecosystems in the Southeastern Crimea region. The obtained data provide valuable insights for the development of sustainable vegetation resource management strategies and climate change adaptation in the region. Full article

This paper reports on the location of sources contributing to a point flux measurement in the southern taiga, Russia. The measurement tower is surrounded by a coniferous forest with a mean aerodynamically active height of 27 m (h). Aerodynamical parameters of the forest, such as displacement height d and aerodynamic roughness $z_0$, derived from wind speed profile measurements for 2017–2019, were used to estimate the seasonal and daily behavior of the flux footprint. Two analytical footprint models by Schuepp et al. and by Kormann and Meixner driven by d and z₀ were used to estimate the footprint for canopy sources. The Lagrangian simulation (LS) approach driven by flow statistics from measurements and modeling was used to estimate the footprint for ground-located sources. The Flux Footprint Prediction (FFP) tool for assessing canopy flux footprint (Kljun et al.) applied as the option in the EddyPro v.7 software was inspected against analytical and LS methods. For model comparisons, two parameters from estimated footprint functions were used: the upwind distance (fetch) of the peak contribution in the measured flux (X_max) and the fetch that contributed to 80% of the total flux (CF₈₀). The study shows that X_max varies slightly with season but relies on wind direction and time of day. All methods yield different X_max values but fall in the same range (60–130 m, around 2–5 h); thus, they can estimate the maximum influence distance with similar confidence. The CF₈₀ values provided by the FFP tool are significantly lower than the CF₈₀ values from other methods. For instance, the FFP tool estimates a CF₈₀ of about 200 m (7 h), whereas other methods estimate a range of 600–1100 m (25–40 h). The study emphasizes that estimating the ground source footprint requires either the LS method or more complex approaches based on Computational Fluid Dynamics (CFD) techniques. These findings have essential implications in interpreting eddy-flux measurements over the quasi-homogeneous forest. Full article

This study investigates the prospects for preserving the main Pinus sylvestris L. (Scots pine) ecotypes in Poland, considering the habitat conditions of their occurrence. Scots pine is known for its wide distribution and natural adaptability to various habitats. However, there is an increasing vulnerability of pine forests to damage from biotic factors and a decrease in natural regeneration, particularly in areas under legal protection. Additionally, projected climate change has raised concerns about the future of Pinus sylvestris, placing it in the “losing” group of tree species. The aim of the study was to analyze the habitat conditions of the seven main selected Pinus sylvestris L. ecotypes to assess the sustainability of pine stands in their natural habitat conditions. Out of the seven populations of studied pine ecotypes, only one grows under conditions representing a typical form of pine forest (Leucobryo–Pinetum plant association). Two populations grow under conditions corresponding to potential deciduous forests (Galio sylvatici–Carpinetum and Calamagrostio arundinaceae–Quercetum petraeae). The remaining populations represent potentially mixed oak–pine forests. Such a distribution of plant communities, except for Leucobryo–Pinetum, does not guarantee the continuity of the studied pine stands as a result of their natural regeneration. Therefore, it is necessary to preserve the offspring of the studied populations outside their occurrence sites, but the studied pine stands should be preserved until their natural death in their natural habitats. In the conducted research, the NDVI turned out to be very useful, showing a high correlation with the trophicity of habitat expressed in the diversity of plant communities, as well as with the height and diameter of the studied stands. Full article

This study aims to characterize forest cover transitions in North Korea and identify deforested areas that are degraded or at risk of degradation. We used phenological information and random forest classifiers to perform a deforestation classification. We then extracted the two main forest cover loss patterns, sloping farmland (farmland with slope greater than 6 degrees) and unstocked forest (crown cover less than 20%), for the years of 2000, 2010, and 2020. Based on the deforestation map of each year, we analyzed the deforestation dynamics from 1990 to 2020. Forests showed decreases in cover by 27% over the 30-year study period and accounted for 41.5% of the total land area in 2020. Deforestation spread into the core area, which led to severe shrinkage and fragmentation of forests. Unstocked forest and sloping farmland experienced the highest rates of loss among the forestland uses and accounted for 48.9% and 39.3% of the total loss over the study period, respectively. During the study period, 25,128 km², 5346 km², and 6728 km² of forestland was cleared, degraded, and was at risk of degradation or barrenness by artificial repeated fires, respectively. This methodological framework provides a valuable template for areas that are difficult to access, and the deforestation dynamics results can provide a basis for conservation and sustainable management of forest resources. Full article

To explore the reasons for the differences in flower bud differentiation in Camellia oleifera under different sink–source relationships, different types of new shoots (T1 and T2) were selected to represent different sink–source relationships (new shoots with one fruit borne alongside at the bottom of the new shoots-T1; new shoots without one fruit borne alongside at the bottom of the new shoots-T2), and the flower bud differentiation rate, endogenous hormones and photosynthetic characteristics were determined. With the increase in the sink, the flower differentiation rate decreased significantly and the IAA and GA₃ content in the leaves and ABA content in the buds increased significantly, while the GA₃ and ZT content in the buds decreased significantly, which were significantly and positively correlated with the flower differentiation rate, with correlation coefficients of 0.777 and 0.817, respectively. Furthermore, an increase in the number of sinks contributed significantly to the increase in soluble sugar and starch content in leaves, while the soluble sugar and starch content in flower buds decreased significantly with the increase in sinks, with maximum differences of 3.45 mg·g⁻¹ (soluble sugar in leaves), 4.09 mg·g⁻¹ (soluble sugar in flower buds), 7.08 mg·g⁻¹ (starch in leaves) and 4.87 mg·g⁻¹ (starch in flower buds), and the high soluble sugar and starch content in flower buds at preflower bud differentiation with correlation coefficients of 0.854 and 0.837, respectively. The chlorophyll content and net photosynthetic rate increased with increasing sinks. In the presence of fruit at the base of the new shoot, more ¹³C assimilates were allocated to fruit and less to flower buds, resulting in a decrease in the rate of flower bud differentiation. The ¹³C assimilate allocated to the flower buds of T1 (6.71 mg·g⁻¹) was significantly lower than the ¹³C assimilate allocated to the flower buds of T2 (10.26 mg·g⁻¹) during late bud differentiation, and the difference between T1 and T2 was greatest during this period. Our work demonstrated that the sink–source relationship regulated Camellia oleifera flower bud differentiation by influencing endogenous hormones and photosynthetic characteristics. To achieve stable production of Camellia oleifera in successive years in the future, the ratio of the number of new shoots of the two types in relation to the different sink–source relationships should be reasonable. Full article

China’s Loess Plateau is both the largest and deepest loess deposit in the world, and it has long been one of the most severely eroded areas on Earth. With the implementation of the Grain-for-Green Project in 1999, the Loess Plateau has become the most successful ecological restoration zone, and soil organic carbon (SOC) sequestration has greatly increased. However, little is known about the balance of SOC sequestration and vegetation restoration on the Loess Plateau. Thus, this review focused on the SOC sequestration from vegetation restoration in this region. Firstly, the current situations and principal aspects of vegetation restoration processes were reviewed, and the effects of vegetation restoration on SOC sequestration were summarized. Secondly, based on the new technologies and methods for soil carbon (C) sequestration, the mechanism of soil microbial C sequestration was described from the molecular level of genes, and some management measures for SOC sequestration were summarized. Finally, we pointed out the main directions in C sequestration mechanisms for vegetation restoration depending on the basic process of the C cycle, which should integrate into physics, chemistry, and biology. Overall, this review will help us understand the SOC sequestration function and the ecological benefits of vegetation restoration on the Loess Plateau. Full article

Understanding the relationship between soil environmental conditions and the interspecific integration of plant traits might shed light on how plants adapt to their environment. In order to clarify the adaptation strategies of desert plants in the various habitats, this study calculated interspecific trait integration (ITI) and plant trait networks (PTN) by selecting plants from high water-salinity habitat (HSM) with salt stress and low water-salinity habitat (LSM) with drought stress in the Ebinur Lake region. Eight different phytochemical traits were taken into consideration, including carbon (C), nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), sodium (Na), and magnesium (Mg). Six soil factors were chosen, including soil pH, water content (SVWC), electrical conductivity (EC), soil nitrogen (N), phosphorus (P), and potassium (K). The results obtained are shown below: (1) the relationship between plant leaf chemical traits was closer in HSM than in LSM, and the correlation between C and other leaf chemical traits was significant in HSM and insignificant in LSM; (2) the correlations between soil factors and ITI were not statistically significant; however, in both soil water-salinity habitats, the strength of fit between SVWC and ITI was the greatest, while the strength of fit between EC and ITI was the smallest; and (3) according to the PTN, C and Ca are the two most central traits for the growth of desert leaf chemical plants in Ebinur Lake, which is consistent with the results of the PCA. Coordination of plant leaf traits along water-salinity gradients involves many different combinations of traits, and the use of ITI and PTN can quantify the complex relationships between multiple traits to a greater extent, highlighting the multivariate mechanisms of plant response and adaptation to soil habitats. This information will help expand and optimize our ability to observe and predict desert plant responses to habitat change, providing powerful insights for assessing desert plant survival strategies. Full article

Stem profile modeling is crucial in the forestry sector, particularly for commercially valuable species like teak (Tectona grandis Linn F.), whose value depends on its stem dimensions, heartwood proportion, and age. We proposed a nonlinear mixed-effect model to describe the evolution of the stem and heartwood profiles of clonal teak trees with ages between 4 and 12 years in the Brazilian Amazon. Tapering models were used to estimate the bark, bark-free, and heartwood diameters. Dummy variables were included in each tapering model to estimate each type of diameter and enable compatibility. We used mixed models with age as a random effect in order to improve the accuracy. The Demaerschalk model provided the most accurate and compatible estimates for all three types of stem diameter. Also, age as a random effect significantly improved the model’s accuracy by 7.2%. We observed a progressive increase in the heartwood proportion (14% to 34%) with advancing age, while the proportions of bark (23% to 20%) and sapwood (63% to 45%) showed inverse behavior. The growth rate of the heartwood differed from that of the bark volume, emphasizing the importance of considering the age of heartwood maximization when determining the cutting cycle of the species. Full article

Hydraulic traits are essential functional characteristics of plants related to water absorption, transport, and loss, serving as indicators of a plant’s adaptability to prevailing environmental water conditions. However, the hydraulic traits of shrub, particularly desert plants in arid and semi-arid regions, have been underexplored. In this study, we conducted a pot experiment using Caroxylon passerinum (Bunge) Akhani and Roalson as the subject. Three treatment groups were established: adequate water supply, mild drought, and severe drought. After subjecting the shrub to drought and subsequent rehydration, we measured hydraulic conductivity, net photosynthetic rate, and stomatal conductance. We found that leaf water potential decreased and stomatal conductance and net photosynthesis decreased with increasing drought intensity. We found that leaf water potential and stomatal conductance decreased with increasing drought intensity. Although there was no significant change in hydraulic conductivity in the two drought groups, the values were greater in the drought group than in the control, and greater in the mild drought group than in the severe drought group. Meanwhile, the embolism resistance decreased with increasing drought intensity. After rehydration, hydraulic conductivity did not return to control levels in the severe drought group, as did embolism resistance in the two drought groups, and leaf water potential did not recover significantly. The results showed that drought stress increased the hydraulic conductivity of C. passerinum, and this effect was more pronounced under mild drought stress. After the stress was lifted, C. passerinum continued to maintain a lower leaf water potential to promote water uptake. This result provides a reference for us to study water use of desert shrubs under different drought stresses. Full article

As the climate has warmed, alpine treelines have moved to higher altitudes and the responses of tree growth to different climate factors have changed. We collected dendrochronologies of Larix gmelinii at different elevations on the Dabai Mountain, the highest peak in northeastern China’s Greater Khingan range, to measure the sensitivity and stability of radial growth over time. We found that the treeline has moved upslope since 1970. From the mid-1980s, radial growth increased in the treeline ecotone but decreased in the subtimberline forest, an example of “growth divergence” under warming conditions: increases in the previous October’s maximum temperatures promoted growth at higher altitudes but inhibited it at lower altitudes. The treeline ecotone appears to be more sensitive to climate change, with the effects on tree growth of different climate indicators varying by altitude in linear or U-shaped relationships. As warming continues, the management of boreal forests needs to consider the changing potential for tree growth and carbon sequestration capacity in relation to changing site conditions. Full article

Carbon stored in harvested wood products (HWPs) can play an important role in climate change mitigation and needs to be accounted for accurately and consistently. This study reviewed the features of previous HWP carbon accounting frameworks and discussed potential improvements for a more complete assessment of all HWP contributions to net zero carbon targets at subnational levels. The basic features include the components, the methods, the approaches, and the modeling principles. A key recommendation is to expand previous HWP C accounting framework components to include other climate change mitigation benefits such as local or regional substitution effects (i.e., material replacement, fossil fuel displacement effects, energy efficiency gains, recycling effects, and cascading use impacts) of all produced and consumed HWPs. Another area for improvement is the need for subnational unit-specific activity data and conversion factors. Adopting variants of the domestic origin-stock change approach will also help account for relevant production and consumption activities within the subnational unit. These recommendations will enhance the accuracy and/or precision of HWP accounting frameworks at the subnational level and help capture all potential benefits of HWPs as a carbon sink for climate change mitigation and a valuable contributor to subnational net zero carbon targets. Full article

Weed control is considered a critical management operation for the establishment and growth of Eucalyptus globulus and is often performed during the first two years following planting. However, no information has been found related to the effects of weed management on the long-term growth of E. globulus. This study aims to better understand how adjusting the timing of weed control, beyond tree establishment, affects the productivity of eucalypts on two commercial plantations in Central Portugal. Two treatments were considered: weed control when vegetation cover occupied at least 50% of the area with a mean height of at least 50 cm, and no weed control. At the northernmost site, weed control operations were performed during the first 3 years following planting. At the southernmost site, weed control interventions occurred between 1.5 and 8.2 years. Weed control demonstrated to be effective at diminishing vegetation cover density to a maximum of 79% and 94% in the northmost and southmost sites, respectively. Weed control significantly increased E. globulus productivity by the end of the study, demonstrating that the timing of weed management must be adjusted in accordance with the understory competing vegetation cover (weeds) and during the entire rotation, not only during tree establishment. Full article

The carbon cycle within a terrestrial ecosystem is a pivotal functional process that drives ecosystem evolution, and the precipitation pattern variations exert a profound influence on it. To comprehensively assess the response of carbon release in the global terrestrial ecosystem to water variation, we performed a global meta-analysis by extracting data from 144 publications. Additionally, we incorporated various moderators to elucidate the heterogeneity observed in the data. The results showed that soil carbon release was highly sensitive to water variation, with drying and moisturizing treatments responding differently to water variability. Specifically, drought inhibited the soil carbon release of terrestrial ecosystems (24% reduction in effect size), but precipitation promoted it (11% increase in effect size). Moreover, this sensitivity could be affected by other ambient factors, depending on water manipulation (drying or moisturizing treatment). In moisturizing treatment cases, ambient precipitation, altitude, and vegetation type more or less affected the sensitivity of soil carbon release to a water increase. However, in drying treatment cases, these factors had no significant influence on the water sensitivity of soil carbon release. Unlike the above ambient factors, a temperature increase strengthened this sensitivity in both of the treatments. In addition, our study also showed that the response of carbon release to water variation did not depend on the substrate type or the carbon–nitrogen ratio (C/N) of the substrates, revealing that these effect factors on carbon release on the local scale could be overshadowed by water conditions. Overall, water variation positively affected soil carbon release on the global scale. Particularly, drought had a strong controlling effect on carbon release over the other environmental factors. Therefore, the impact of soil water loss on carbon release should be of great concern for the management of ecosystems and the prediction of carbon release models, especially when high temperatures and drought have been occurring more and more frequently on the planet in recent years. Full article

Woody plants are crucial components of forest ecosystems and play critical roles in regulating community succession and ecosystem function. Studying woody plant diversity and its influencing factors is thus important for understanding and protecting forest ecosystems. Quercus aliena var. acutiserrata is an important deciduous broadleaf species in the warm–temperate forest of central China. Multiple regression and structural equation modelling were used to discuss the effect of biotic and soil factors on tree species diversity across seven relative density gradients of Q. aliena var. acutiserrata trees in this zone. Our results showed that the following: (1) Species diversity showed significant decreasing trends with increasing relative density of Q. aliena var. acutiserrata. (2) As the relative density of the oak tree increased, some biotic factors (canopy density, and mean DBH) and soil factors (Soil SOC, AP, and AK) all showed significantly increasing trends, whereas the DBH variation (CVD) and soil pH displayed decreasing trends. (3) Biotic factor (e.g., mean DBH, CVD, and competition interaction) had strong direct effect on species diversity, and soil factors exerted indirect roles on tree diversity via biotic factors. Our results provide insight into biodiversity protection and scientific management in this warm–temperate natural oak forest. Full article