Objective: To elucidate the genomic characteristics and functional divergence of cinnamoyl-CoA reductase (CCR), a key rate-limiting enzyme in the lignin biosynthetic pathway of Paulownia fortunei, the genome-wide identification and systematic analysis of the CCR gene family were conducted based on the whole-genome data. The lignin synthesis in P. fortunei and the response mechanisms to biotic and abiotic stresses were explored, which would provide a theoretical basis for the targeted breeding of new elite stress-resistant Paulownia varieties via genome editing technology. Method: The known CCR amino acid sequence from Arabidopsis thaliana was used as a query, with which BLAST alignment was performed against the P. fortunei genome database to obtain P. fortunei PfCCRs family members. Bioinformatics techniques were then used to analyze the evolutionary relationships, promoter binding elements, and collinearity of these family members. Real-time quantitative PCR (RT-qPCR) was employed to analyze the expression levels of P. fortunei PfCCRs in different tissues and under abiotic stress conditions. Result: 1) In this study, a total of 14 PfCCR members were identified in the P. fortunei genome, with amino acid lengths ranging from 111 to 360 aa. These members were classified into five subfamilies (Cluster Ⅰ to Cluster Ⅴ) and all contained the NADB_Rossmann domain. 2) The PfCCR promoter regions were enriched with cis-acting elements associated with light response, hormone signal response, and stress response. Furthermore, the PfCCR genes were unevenly distributed across 8 chromosomes, and 10 collinear gene pairs were identified between P. fortunei and the dicotyledonous plants Sesamum indicum (sesame) and A. thaliana CCRs. 3) Phylogenetic tree construction and analysis indicated that PfCCR9 and PfCCR11 clustered together with A. thaliana lignin synthesis regulator AtCCR1 and disease resistance-related gene AtCCR2 in Cluster Ⅰ. Furthermore, the expression of PfCCR9 and PfCCR11 was significantly upregulated under drought and salt stress, suggesting their critical roles in the molecular regulation of stress tolerance. In contrast, PfCCR12 expression was significantly upregulated in seedlings infected with Paulownia witches’ broom phytoplasma (PaWB), indicating an important function in pathogen stress response. 4) PfCCR1, PfCCR3, PfCCR6, PfCCR7, PfCCR11, PfCCR13, and PfCCR14 exhibited significantly high expression in stems, while PfCCR10 and PfCCR11 were highly expressed in roots, indicating that these 8 genes play important roles in lignin biosynthesis. Conclusion: This study has identified key members of the PfCCRs family that play a role in regulating lignin synthesis and stress resistance in Paulownia wood. Based on evolutionary analysis and expression level validation, PfCCR9 and PfCCR11 in Cluster Ⅰ, as well as PfCCR12 in Cluster Ⅰ, play important regulatory roles in stress resistance, making them candidate genes for breeding new stress-resistant Paulownia varieties.

Objective: Cunninghamia lanceolata (Chinese fir) plantations in Fenyi City, Jiangxi Province were targeted. A land expectation value (LEV) model integrating the dynamic coupling between biomass and dead organic matter carbon pools was constructed to clarify the regulatory effect of the carbon pool coupling mechanism on the optimal rotation period and land expectation value of Chinese fir plantations, as well as the effects of key parameters, so as to provide quantitative support for the synergistic management of timber production and carbon sequestration in Chinese fir plantations. Method: Based on 40-year continuous positioning observation data from Chinese fir plantations in Fenyi City, Jiangxi Province, the classic Faustmann model was used as the framework to incorporate the dynamic coupling process of biomass and dead organic matter carbon pools, and set three scenarios: baseline (no carbon sequestration revenue, no nutrient-driven positive feedback, with biomass and dead organic matter carbon pools independent of each other), static carbon sequestration (with carbon sequestration revenue but no nutrient-driven positive feedback), and dynamic coupling (with carbon sequestration revenue and nutrient-driven positive feedback, with two carbon pools dynamically coupled). The dynamic characteristics of carbon pools and LEV under different scenarios were simulated. Furthermore, sensitivity analysis was conducted on three core parameters, carbon price (P_c), nutrient feedback coefficient (λ), and dead organic matter decomposition rate (α), to quantify the influence of key parameters on the optimal rotation period and LEV. Result: 1) The optimal rotation period for all three scenarios was 21 years, but the LEV in the dynamic coupling scenario was the highest (62 555 yuan·hm^?2), which was 169 yuan·hm^?2 higher than that in the baseline scenario and 21 yuan·hm^?2 higher than that in the static carbon sequestration scenario. The revenue increment came from two aspects: firstly, the direct carbon sequestration revenue brought by the increase in total carbon pool storage; secondly, the timber revenue increment driven by nutrient-driven positive feedback that promoted biomass growth and increased the proportion of large-diameter timber. 2) In the dynamic coupling scenario, the nutrient-driven positive feedback loop between the two carbon pools significantly improved the carbon pool accumulation efficiency. At age 21, the biomass carbon pool, dead organic matter carbon pool, and total carbon pool of Chinese fir plantations increased by 8.3%, 7.8%, and 8.2%, respectively, compared with the static scenario. Carbon pool accumulation showed obvious stage characteristics: nutrient cycling and synergistic accumulation between carbon pools were weak during the young forest stage, the difference expanded rapidly in the fast-growing stage, and the carbon pool in the dynamic scenario maintained steady growth in the near-mature stage, with long-term carbon sequestration capacity significantly superior to that in the static scenario. 3) Sensitivity analysis showed that within the range of realistic parameters, key parameters had no impact on the determination of the optimal rotation period, but their effects on LEV were clear: LEV increased significantly with the rise of λ, while the positive impact of P_c on LEV and the negative impact of α on LEV were both very small, with the magnitude of the impact was within 0.05%. Conclusion: Under the current timber-dominated management mode, the dynamic coupling effect between biomass and dead organic matter carbon pools does not change the widely adopted 21-year optimal rotation period of Chinese fir plantations. The dynamic coupling of the two carbon pools offset the discount loss of carbon sequestration through nutrient-driven positive feedback, realizing the coordinated improvement of carbon sequestration and timber revenue. Optimizing understory management of Chinese fir plantations and providing reasonable carbon price subsidies are effective approaches to activate the carbon pool coupling effect and thereby improve plantation management efficiency. This model exhibits strong adaptability to the ecological gradient differences in southern Chinese fir production areas and can provide quantitative technical support for the synergistic management of timber production and carbon sequestration in Chinese fir plantations.

Objective: This study investigates the physiological and biochemical mechanisms by which spermosphere fungi promote the germination of Ormosia henryi seeds, aiming to provide a theoretical foundation and microbial resources for breaking dormancy of seeds with hard seed coats in tree species. Method: Three fungal strains with germination-promoting activity, isolated from the spermosphere soil of O. henryi, were used to evaluate their capacity to secrete seed coat-degrading enzymes and produce endogenous hormones. Three fungal strains were used to initiate germination experiments on O. henryi seeds, and the physiological and biochemical indicators in the seeds were measured at various stages of germination. Seeds treated with conventional methods served as controls to verify the priming germination effects by the fungi. A systematic assessment was carried out to elucidate the physiological regulatory effects of the three spermosphere fungi on germination of O. henryi seeds. Result: 1) The strains SS-1-14, SS-2-3, and SS-2-22 all secreted seed coat-degrading enzymes within 7 days of cultivation. SS-1-14 preferentially degraded the pectin layer, SS-2-3 consistently released highly active pectinase and lipase, and SS-2-22 efficiently disrupted the seed coat barrier at the initial stage by rapidly producing both cellulase and pectinase. 2) All strains produced auxin and cytokinin precursors, thereby promoting embryonic cell differentiation. SS-1-14 generated high levels of indoleacetic acid, salicylic acid, and salicylic acid glucoside, which both promote growth and activate systemic resistance. SS-2-3 produced higher quantities of indole-3-acetonitrile, tryptamine, and zeatin, which directly influence cell division and plumule differentiation. SS-2-22 primarily synthesized auxin and cytokinin precursors of N6-isopentenyladenosine and isopentenyladenine, which were converted into active hormones to reduce metabolic burden. 3) The priming effect of spermosphere fungi effectively promoted seed germination by dynamically regulating antioxidant enzymes and storage material metabolism in O. henryi seeds. The three strains enhanced antioxidant capacity by regulating CAT and PPO throughout germination, and POD and SOD during the last stage. SS-1-14 exhibited the most pronounced regulatory effect, significantly increasing SOD activity in the last stage of germination by 19.10%, and CAT activity in the early and last stages of germination by 127.13% and 41.20%, respectively. The three strains promoted storage material mobilization by regulating protease and lipase activities throughout germination, as well as amylase and acid phosphatase activities in the last stage of germination. SS-1-14 exhibited the most pronounced effect, increasing protease and lipase activities by 67.31% and 58.61% in the early stage of germination, and by 77.16% and 59.32% in the last stage of germination, respectively. All three strains were able to accelerate macromolecule degradation and micromolecule generation throughout germination, among which SS-1-14 had the best comprehensive effect, increasing triglyceride degradation by 32.20% in the early stage of germination and starch degradation by 60.51% in the last stage of germination, and accelerating ATP production by 188.83% in the early stage of germination and soluble sugar accumulation by 65.24% in the last stage of germination. 4) Compared with traditional physical and chemical treatments such as scarification, acid etching, and hot water soaking, fungal induction reduced seed electrical conductivity and MDA content, alleviated oxidative damage during germination, and preserved cell membrane integrity. Conclusion: Spermosphere fungi promote the germination of O. henryi seeds through a multidimensional “physical-chemical-biological” priming mechanism. This mechanism involves secreting enzymes that degrade the seed coat to overcome mechanical barriers, synthesizing phytohormones to activate seed physiological activity, and enhancing antioxidant and material-converting enzyme systems to reduce germination-induced damage and facilitate storage material mobilization.

Objective: To quantitatively evaluate the variations in soil retention within the Chongqing section of the Three Gorges Reservoir area based on multi-source spatiotemporal data, this study analyzed the comprehensive driving mechanisms of various factors to reveal the impact mechanism of acid deposition on the numerical product of the cover-management factor (C) and the support practice factor (P) (hereafter referred to as the composite factor C×P, used to characterize the comprehensive surface anti-erosion capacity), aiming to provide a scientific basis for the prevention of soil erosion and the optimization of ecological barrier in the reservoir area. Method: Based on digital elevation model (DEM), land use, and acid deposition data from 2005 to 2020, the InVEST-SDR module was used to estimate soil retention. The geographic detector was applied to identify the dominant factors of soil retention and their interaction effects. Ordered Logistic regression and XGBoost-SHAP methods were used to quantitatively explain the linear and nonlinear impact mechanisms of acid deposition on the composite factor C×P. Result: 1) Total soil retention first increased and then decreased, rising from 6.74×10¹⁰ t in 2005 to a peak of 8.11×10¹⁰ t in 2015, and then falling to 7.87×10¹⁰ t in 2020. Spatially, it presented a pattern of “high in the east and low in the west, high in the northeast and low in the southwest”. High-value areas of soil retention per unit area (>3 000 t·hm^?2a^?1) were mostly located in steep slope zones with high canopy closure forests such as Wuxi and Yunyang, while low-value areas (<500 t·hm^?2a^?1) were located in densely constructed areas such as the main urban area of Chongqing and Fuling. 2) From 2005 to 2020, construction land expanded at an annual rate of 3.2% to 7.5%, cropland was mainly converted to forest land (decreasing by 3.9%), and open broadleaved forest land degraded significantly (decreasing by 90%). 3) Acid deposition showed significant spatiotemporal differentiation. The total sulfur deposition flux decreased from 41.41 kg·hm^?2a^?1 in 2005 to 30.23 kg·hm^?2a^?1 in 2020, while the total nitrogen deposition flux increased from 43.12 kg·hm^?2a^?1 in 2005 to 46.84 kg·hm^?2a^?1 in 2020. 4) The analysis results based on geodetectors indicated that land use was the dominant factor, and the interaction between acid deposition and land use had the strongest explanatory power (q=0.218 8). Logistic regression showed that the effect of nitrogen deposition on elevating the C×P level was approximately 8 times that of sulfur deposition. XGBoost-SHAP revealed that acid deposition exhibited nonlinear and spatially heterogeneous effects, with the main urban area and the southwest being hotspot areas. Conclusion: Acid deposition intensifies the spatial heterogeneity of soil retention in the reservoir area through the synergistic pathways of chemical erosion and biological inhibition with land use change. Ecological protection should prioritize reducing nitrogen deposition emissions, restoring sparse forest land, and improving forest land quality.

Objective: This study aims toelucidate the differentiated threshold responses of landscape patterns within lake and river wetland buffer zones along a gradient of human activity intensity, thereby providing a scientific foundation for hierarchical protection of wetland ecological spaces and targeted regulation of human activities. Method: The lake and river wetlands in Wujiang District, Suzhou was targeted, and buffer zones were established along the shorelines. Based on a comprehensive characterization of the spatial characteristics of human activities in the region, a human activity intensity (HAI) index was constructed by weighting five indicators including proportion of construction land, proportion of cultivated land, proportion of pond area, road network density, and density of transportation service facilities using an AHP-entropy combined weighting method. The HAI was spatially expressed within unified spatial units to analyze its gradient distribution characteristics in lakeside and riverside buffer zones. Further, FRAGSTATS was used to calculate multiple landscape metrics and reveal spatial differentiation patterns of landscape structure within wetland buffer zones. Finally, binary regression models were employed to explore nonlinear relationships between HAI and landscape patterns and to identify critical thresholds of HAI. Result: 1) Human activity intensity and landscape patterns displayed distinct spatial differentiation in the buffer zones of lakeside and riverside. In lakeside buffer zones, HAI exhibited “peak-type” or “valley-type” disturbance patterns within the buffer zone of 0–3 600 m, while landscape indices such as patch density, largest patch index, connectivity index, and aggregation index fluctuated considerably within the buffer zone of 0–1 800 m. In contrast, riverside buffer zones showed a gradient decay in HAI, with landscape indices responding consistently within the buffer zone of 0–1 800 m. 2) Landscape patterns responded to HAI in a significantly nonlinear manner: indices such as patch density, connectivity index, aggregation index, Shannon’s diversity index, and Shannon’s evenness index followed an inverted U-shaped trend, while largest patch index exhibited a U-shape pattern. This reflects an evolutionary trajectory of landscape patterns characterized by “fragmentation→diversity enhancement→reintegration”. 3) Different disturbance thresholds were identified for lakeside and riverside buffer zones (0.22 and 0.18, respectively), suggesting stronger disturbance resistance in lakeside buffers and higher ecological vulnerability and degradation risk in riverside buffers. Among the metrics, patch density and aggregation index were the most sensitive to human disturbance. Conclusion: The impact of human activities on landscape patterns within wetland buffer zones exhibits significant distance dependence and threshold effects. Controlling human activity intensity within critical thresholds can effectively maintain the connectivity and diversity of wetland landscapes.

Objective: This study aims to explore and identify key factors influencing the quantity of natural forest regeneration by developing a random forest model, so as to provide a theoretical basis for the sustainable management of natural forests in the central of Daxing’anling region. Method: Based on the survey data from 96 standard sample plots in Cuigang forest farm, Xinlin forest farm, and Zhuangzhi forest farm under the Xinlin Forestry Bureau, 29 basic indicators were selected across six categories: stand characteristics, site conditions, soil conditions, tree size diversity, species diversity, and stand spatial structure. Poisson model, negative binomial model, and random forest regression model were used to construct regeneration quantity models for Larix gmelinii and Betula platyphylla. After model optimization, the OOB permutation method was used to evaluate the contribution of each predictor variable to the regeneration quantities of L. gmelinii and B. platyphylla. Result: The ten-fold cross-validation test showed that the accuracy of the random forest regeneration prediction model was significantly higher than that of the Poisson model and the negative binomial model. The root mean square error ( RMSE) was 482 and 682 tree·hm^?2, and mean absolute error (MAE） was 377 and 460 tree·hm^?2 for L. gmelinii and B. platyphylla, respectively. The OOB permutation method identified the most important variables for L. gmelinii regeneration as: Shannon index of diameter at breast height (DBH) (17.57%), Pielou’s evenness index of DBH (16.88%), stand volume per unit area (13.29%), Simpson index of DBH (12.92%), and mean DBH (12.91%). For B. platyphylla, the key variables were: Shannon index of DBH (18.53%), Pielou’s evenness index of DBH (16.13%), herbaceous cover (12.62%), mean DBH (12.34%), and shrub cover (11.31%). Conclusion: Tree size diversity and stand density are key factors influencing regeneration. Nurturing harvesting or replanting strategies can ensure scientific and reasonable stand density, thereby promoting natural regeneration and supporting the ecological succession of forest ecosystems.

Objective: Current manual binding soil balls of large tree roots is labour-intensive, requiring three-person coordination. To address the issues of manual reliance, low efficiency, and lack of available machinery in binding soil balls of large tree roots during transplantation, this paper designs an in-situ binding apparatus for large tree root soil balls along with its binding strategy. Method: By analysing manual binding trajectories, a modular positioning clamping mechanism was designed. This mechanism was adjusted radially with ten fastening bolts to accommodate large trees with trunk diameters ranging from 150 to 220 mm, ensuring coaxial alignment with the trunk. A composite motion combining gear-ring meshing transmission and synchronous belt drive were used to form a helical binding trajectory for precise angular control. An integrated tension control mechanism was used to stabilize strap tension and reduce errors. A discrete element model of the root-soil composite was established in EDEM. Shear and firmness tests validated a relative error below 5%. A three-factor quadratic orthogonal test was conducted for bundling and lifting container simulations, using soil retention rate and strap retention rate as evaluation metrics. Result: Orthogonal tests yielded optimised parameters: 18.5 diagonal wraps, 47° binding angle, and binding tension of 20 N. Under these conditions, soil retention rate reached 85.10% and fabric retention rate was 26.66%. The actual container lifting experiments verified that the maximum relative error was below 6% compared to simulation results, indicating the parameter reliability. A foam root ball test rig was designed for bench testing, determining the optimal speed combination with the circumferential stepper motor of 76.5 r·min^?1 and the vertical stepper motors of 45 r·min^?1. This configuration achieved a tension fluctuation rate ≤6% and a total binding time ≤210 s. Conclusion: Field trials were conducted on tree root balls with diameters ranging from 0.9 to 1.5 m using this speed combination. The overall bundling efficiency increases by a maximum of 39.69% and the soil retention rate increases a maximum of 8.41% compared to manual bundling. The device weighs 10.75 kg, and can be installed, wrapped, and disassembled by a single operator, significantly reducing labour intensity. When lifting and packing, a small amount of soil falls off and the root system is not damaged, validating the device's practicality, and providing a reliable solution for mechanizing large tree transplantation.

Objective: The objective of this study is to explore the diversity of moths in Pinus tabuliformis plantations under different environmental conditions and the differential regulation mechanisms of environmental factors under different site conditions on the diversity of omnivorous and obligate moths, thereby providing a scientific basis for the biodiversity conservation in P. tabuliformis plantations. Method: Eight P. tabuliformis plantations were selected as plots in the plain region (Tongzhou) and the low mountains region (Xishan) of Beijing. The vegetation factors and environmental temperature and humidity were investigated. Moths in plantations were collected by spotlighting and identified by morphological and molecular biological techniques. Result: 1) A total of 4 569 moths belonging to 227 species in 25 families were collected. The results of α-diversity analysis showed that there were differences in the moth community between pure P. tabuliformis plantations (Tongzhou) and near-natural P. tabuliformis plantations (Xishan) (P<0.05). The proportion of pine-eating moths in pure plantations was 6.5% higher than that in near-natural plantations, and the moth number of common species in pure plantations was 29.7% higher than that in near-natural plantations. 2) The results of β-diversity analysis indicated that the composition similarity of the Noctuidae family, which ranked fifth in species richness, was the lowest (Anosim R = 0.77), showing high sensitivity to environmental changes and could be used as a powerful family to distinguish different ecological environments. 3) The Margalef index was significantly positively correlated with the height and species of understory vegetation, but significantly negatively correlated with soil temperature and canopy closure. The Margalef index was the highest when the height of understory vegetation was about 1.05 m. Omnivorous moths were more sensitive to the height, species and quantity of understory vegetation, while obligate moths were mainly affected by tree diameter at breast height. Conclusion: The abundance of moths is mainly affected by environmental factors such as the height of understory vegetation, the vegetation species and soil temperature. Different moth species show significant preferences for environmental factors, among which the structural characteristics of vegetation have the most significant impact on the distribution of most moth species. This study indicates that understory vegetation plays a key role in influencing the species diversity of moths.

Objective: This study aims to investigate the foraging selection and adaptability of Nipponia nippon that has long inhabited inland environments to coastal food resources, and to provide a scientific basis for the feasibility assessment, provenance selection, and wild training of N. nippon in re-introduction to the eastern coastal areas. Method: In this study, 51 captive N. nippon trained in the wild in Beidaihe National Wetland Park were used as objects, and six common coastal mudflat species of clam worm, mantis shrimp, siphon-worm, razor clam, short necked clam, and sea crab were selected for feeding experiments in a simulated tidal pool, together with their traditional freshwater food loach. The all-occurrence sampling method was used to record the foraging behavior of the individuals. Before and after feeding on coastal food, fecal samples and blood samples were collected to detect changes in hormone levels and serum biochemical indicators. Independent samples t-test was used to analyze the foraging preference of individuals of different ages for coastal food, and paired samples t-test was used to analyze changes in physiological indicators before and after feeding on coastal food. Result: N. nippon was able to feed on 4 out of the 6 coastal mudflat food species, namely clam worm, mantis shrimp, siphon-worm, and razor clam, which accounted for 44.1% of their daily food intake. There were age-related differences in the preference for coastal food. The food intake of subadults was significantly higher than that of juveniles (P<0.01) and adults (P<0.01), indicating that the subadult stage is a key period for dietary transition. With the extension of the experimental period, the food intake of some coastal food species by N. nippon and the adaptability to these foods increased 53.4% accordingly, suggesting that long-term acclimatization is beneficial to the dietary transition of N. nippon. After feeding on coastal food, the concentrations of corticosterone (P<0.01) and secretory immunoglobulin A (P<0.01) in fecal samples increased significantly, and the content of albumin (P<0.05) in serum also increased significantly. Conclusion: N. nippon can partially feed on specific species of coastal food, and subadults in particular show significantly stronger foraging selection for coastal food, making them suitable as the main group for re-introduction in coastal areas. After feeding on coastal food, N. nippon exhibits a certain degree of hemoconcentration, indicating that traditional freshwater food is indispensable.

Objective: Considering the current lack of clarity regarding the influence mechanism and the insufficient quantitative prediction of the physical and mechanical properties of bamboo scrimber resulting from the drying process parameters of phenolic resin impregnated heat-treated bamboo bundles (PHB), the Grey Wolf Optimization algorithm combined with a Back Propagation Neural Network (GWO-BPNN) was employed to predict and elucidate the response relationship between the drying process parameters of PHB and bamboo scrimber performance. This study aims to provide a theoretical foundation for achieving efficient PHB drying and precise control over the properties of bamboo scrimber. Method: With the drying temperature, drying time, and moisture content after drying of PHB as input variables, and the water absorption rate, thickness swelling rate, width swelling rate, modulus of rupture (MOR), modulus of elasticity (MOE), and horizontal shear strength (HSS) of bamboo scrimber as output variables, a dataset of physical and mechanical properties was systematically constructed. On this basis, a GWO-BPNN model was constructed and trained. Subsequently, the performance of the proposed model was comprehensively evaluated using five key indicators: Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE), Mean Absolute Percentage Error (MAPE), and Coefficient of Determination (R²). Finally, the developed GWO-BPNN model was applied to a set of independent new datasets for validating the reliability of the proposed model. Result: The GWO-BPNN model demonstrated excellent adaptability and prediction accuracy in estimating the water absorption rate, MOR, MOE, and HSS of bamboo scrimber. The R² was closed to or surpassed 0.9, and the MAE, MSE, RMSE, and MAPE were maintained at relatively low levels. However, the prediction performance for the water absorption thickness swelling rate was moderate (R² = 0.78), and the prediction for the width swelling rate was unsatisfactory (R² = 0.11). Verification results indicated that the overall predicted values of the model exhibited high consistency with the actual measured values. As the drying temperature increased from 50 °C to 80 °C, the water absorption rate and thickness swelling rate of bamboo scrimber rose, whereas the variation in the width swelling rate remained no significant change. The MOR, MOE, and HSS generally followed a trend of initially increasing and subsequently decreasing. When the drying temperature of PHB was set at 60 °C and the moisture content was 10%, the three mechanical property indicators achieved their optimal values. As the moisture content of PHB increased from 5% to 20%, the water absorption rate and width swelling rate of bamboo scrimber exhibited a downward trend. Notably, the thickness swelling rate under a 5% moisture content condition was significantly higher compared to other moisture content conditions, and the mechanical properties demonstrated a trend of first increasing and then decreasing. Conclusion: The GWO-BPNN model proves highly effective in predicting the relationship between the drying process parameters of PHB and the physical and mechanical properties of bamboo scrimber. Specifically, the model exhibits strong predictive accuracy for key performance indicators, including water absorption rate, MOR, MOE, and HSS, with correlation coefficients (R) surpassing 0.9 across all these parameters. The model demonstrates excellent overall fitting accuracy and predictive capability. However, its performance in predicting thickness and width swelling rates resulting from water absorption is relatively less accurate. Based on these findings, the model can provide a solid theoretical basis for optimizing critical drying parameters such as drying temperature, drying duration, and final moisture content of PHB, and thereby facilitates more efficient drying processes and precise control over the performance attributes of bamboo scrimber.

Objective: As the world’s largest importer of wood, China is frequently alleged to be the “chief culprit behind deforestation” and a “black hole for global forest resources”. This study aims to clarify the relationship between China’s wood imports and the wood production and deforestation in source countries, thereby addressing these accusations through empirical research. Method: In this study, a constructed theoretical logic chain was used to systematically analyze the adjacent node connections between China’s wood imports and deforestation, on which a panel data model was employed to empirically investigate the impact of China’s wood imports on the log output of source countries using data from 37 countries spanning 2003 to 2022. Result: 1) Accusations of deforestation linked to China’s wood imports is characterized by uncertainties at every stage of the theoretical logic chain, making it difficult to definitively attribute global forest destruction to China. Even if some responsibility exists, its extent is minimal. 2) China’s wood imports had a statistically significantly positive impact on the output of timber from importing source countries, but the degree of impact was small. Specifically, a 1% increase in China’s imports from a source country was associated with only a 0.070% rise in the country’s log output. Robustness checks and endogeneity analyses have confirmed these findings. Consequently, while a link exists, the negligible magnitude of this effect suggests that accusations blaming China’s wood imports for substantial global deforestation are exaggerated and lack empirical support. 3) China’s timber imports had no significant impact on the output of log from importing countries during 2003—2007. Although there was a significant positive effect in 2008—2019 and 2020—2022, the magnitude gradually declined. The impact was significant for countries with medium-to-high export dependence (coefficients: 0.089, 0.084) and smaller economic sizes (0.098), but insignificant for low-dependence or larger economies. Similarly, effects were significant for middle- and low-income countries (0.084) but not for high-income ones. Notably, while non-tropical wood imports had a modest effect (0.022), tropical wood imports showed a substantial impact (0.194). Collectively, the heterogeneous effects do not support the narrative that China’s wood imports drive widespread deforestation. 4) Free trade agreements (FTAs) with China positively moderated the relationship between China’s wood imports and the log output of source countries, whereas the moderating effect of the exchange rate of the currency of the source country on imports was relatively weak compared to the RMB. Conclusion: China should proactively address these accusations, timely reform its “high-volume throughput” forest product trade model, focus on cultivating domestic forest resources and developing the local forest product market, optimize the structure of wood import sources, improve environmental clauses related to sustainable forest management in FTAs, promote wood legality verification and forest certification processes, and standardize the overseas forestry operations of Chinese enterprises. Collectively, these measures will contribute to the sustainable development of overseas forests.

Objective: This study aims to scientifically assess the water ecological security status of the Xishuangbanna Lancang River Basin, and identify the current problems and their causes, so as to provide a theoretical basis for formulating effective measures to protect and manage watershed water ecological security and promoting sustainable development in the basin. Method: This study was conducted in the Xishuangbanna section of the Lancang River Basin. The pressure-state-response (PSR) model was adopted as the theoretical framework, to construct a comprehensive evaluation index system that includes water resources, water environment, aquatic ecosystems, and socioeconomic conditions. With the statistical and monitoring data from 2012 to 2022, the entropy weight method was applied to determine the weights of each indicator. The comprehensive index method was used to calculate subsystem scores of three subsystems: pressure, state, and response, as well as the overall water ecological security index. The evolutionary characteristics of the basin were identified, and the water ecological security levels were then classified. Result: From 2012 to 2022, the water ecological security level of the Lancang River Basin in Xishuangbanna exhibited a “low-rapid rise-stabilization” trend, with an overall increase of nearly 80%, indicating a generally improving ecological condition. The pressure index showed a “decline-rebound-decline again” pattern, indicating that ecological stress remains long-term characteristics. The state index steadily increased before and after 2019, reflecting a gradual improvement in ecosystem health. The response index has grown significantly since 2015, reflecting that under the promotion of national ecological civilization policies, local governments are shifting their governance from external input driven to endogenous institutional adjustment. Conclusion: The PSR-based evaluation system can effectively reveal the evolutionary path of water ecological security in the Lancang River Basin, Xishuangbanna. The health status of the basin’s water ecosystem continues to improve, and there is a trend of significant synergy evolution between governance response and ecological status. The endogenous institutional dynamics is gradually emerging, and the value of eco-products is accelerating realization. However, there are still bottlenecks in relieving ecological pressure, and the resilience and coordination ability of the governance system needs to be further improved. Therefore, the study proposes policy recommendations including strengthening pressure identification and source control, building a composite governance system, and reinforcing the national ecological security barrier. These insights offer theoretical and practical guidance for similar river valley regions in China’s border areas undertaking water ecological security assessments.

Objective: This study aims to clarify the impact of sustainable forest management certification on the realization of the value of forestry eco-products, so as to provide a scientific basis for promoting the diversity, stability, and sustainability of forest ecosystems. Method: Based on forest resource survey data from 3 170 subplots in Shunchang County, Fujian Province, the propensity score matching (PSM) model was used to analyze the impact of sustainable forest management certification by Forest Stewardship Council (FSC) on the realization of forestry ecological product value from two dimensions: forest asset value and forest carbon sequestration. The robustness of the model was tested using data subset analysis, substitution of dependent variables, and random sampling simulations were conducted 1000 times to draw kernel density curves for placebo testing. Result: FSC certification significantly promotes the realization of forestry ecological product value from two aspects: enhancing forest product value and carbon sequestration effect, and the model robustness test is good. There is a positive synergistic effect between FSC certification and the management goal of large-diameter timber, and certification can significantly enhance the forest value and carbon sequestration capacity of forests with large-diameter timber as the management goal. Conclusion: FSC promotes the realization of eco-product value through a dual path of ecological restoration mechanism and market premium mechanism. Differentiated certification promotion strategies should be adopted for different management characteristics, and FSC certification should be more inclined to be promoted in non intensive forest land and forest land with large-diameter timber management goals, promoting the sustainable development of forest ecosystems, and promoting the modernization of forestry with harmonious coexistence between humans and nature.

Objective: This study aims to investigate the correlation between climate policy uncertainty and the high-quality development of forestry, deeply understand the influence mechanism, quantitatively assess the risks and opportunities brought by climate policy uncertainty to the high-quality development of forestry, and explore effective ways for high-quality development of forestry. Method: The panel data from 31 provinces (autonomous regions, municipalities) in China from 2012 to 2022 was used to construct a comprehensive evaluation index system for the high-quality development of forestry. The entropy method was used to measure the level of high-quality development of forestry in 31 provinces (autonomous regions, municipalities). The two-way fixed effect model and the mediation effect model were used to empirically analyze the causal relationship and mechanism between climate policy uncertainty and the high-quality development of forestry. Result: 1) Climate policy uncertainty had a significant negative impact on the level of high-quality development of forestry, and this result remained valid after a series of robustness tests. 2) Climate policy uncertainty inhibited the high-quality development of forestry by reducing the input of scientific and technological human resources in the forestry sector. 3) The negative impact of climate policy uncertainty on high-quality forestry development was more pronounced in eastern regions, areas with scarce forest resources, and regions dominated by collective forests. 4) The negative impact of climate policy uncertainty on the high-quality development of forestry only occurred when the climate policy uncertainty index exceeded the threshold value. conclusion: Climate policy uncertainty inhibits the level of high-quality development of forestry by reducing the input of scientific and technological human resources in the forestry sector, and its impact is heterogeneous. To address this, it is necessary to moderately enhance the consistency and continuity of different climate policies, strengthen information communication before policy introduction and information disclosure during the implementation process, and ensure that forestry-related departments can timely, comprehensively, and accurately understand the specific content of climate policies, thereby using market and technological means to cope with the negative impacts brought by climate policy uncertainty through multi-channels.

Desertification is a major ecological and environmental trouble that constrains global sustainable development. Effective mitigation of desertification hinges upon a comprehensive understanding of the interactions between sparse vegetation and wind blow in arid and semi-arid regions. Current research on the windbreak mechanisms of sparse vegetation has not yet to establish a systematic framework of the entire process from static morphological traits, wind-induced dynamic responses to flow field modifications, thereby hindering the integration of multi-scale interactions. Therefore, this review takes the conceptual chain of “static morphology-dynamic response-aerodynamic effect-windbreak mechanism” as the main line, and systematically synthesizes the windbreak mechanisms of sparse vegetation. Regarding static morphological structure, the windbreak efficacy of vegetation is predominantly regulated by structural attributes such as porosity, geometry, flexibility, and phenophase characteristics. The optimal porosity threshold for wind protection varies with the vegetation type. Plant geometric architecture modulates the flow field by altering airflow pathways, regulating aerodynamic drag, and redistributing shear stress. Flexibility further optimizes windbreak function, collectively shaping the spatial heterogeneity of wind protection. In terms of wind-induced dynamic responses, vegetation adapts to wind loading primarily through two pathways: swaying and morphological reconfiguration. Swaying characteristics are predominantly governed by morphological structure, with natural frequency and damping ratio serving as key quantitative parameters for characterizing dynamic responses. Morphological reconfiguration achieves dynamic drag reduction adaptation through streamlining and a decrease in windward area. Regarding aerodynamic effects, these effects represent the pivotal link in wind flow modulation by vegetation. The drag coefficient is a core physical parameter for quantifying the wind resistance effect, directly reflecting the capacity of vegetation to dissipate airflow kinetic energy. In contrast to rigid vegetation models, the drag coefficient of flexible vegetation exhibits a decreasing trend with increasing wind speed. Furthermore, the nonlinear relationship between drag coefficient and porosity is due to the coupling effect of multiple physical processes. In studies of static windbreak mechanisms, models for flow recovery in the lee side have evolved from empirical formulations to coupled mechanistic-statistical models, significantly enhancing predictive accuracy and physical interpretability. Dynamic windbreak mechanisms primarily encompass two pathways: morphological reconfiguration coupled with aerodynamic load regulation, and structural flexibilization coupled with energy dissipation. However, existing research on dynamic mechanisms predominantly focuses on trees, whereas investigations into the dynamic responses of shrubs, which are widely distributed in arid and semi-arid regions, remain remarkably limited. Targeted studies are urgently needed to address this knowledge gap. In summary, the windbreak process of sparse vegetation fundamentally represents a concurrent, multi-scale, dynamically interactive physical continuum. In the future, it is necessary to conduct systematic research on the multidimensional coupling of “static morphology-mechanical properties-aerodynamic effects-flow field modulation-windbreak function”, aiming to construct a comprehensive theoretical framework describing the entire windbreak process for sparse vegetation. Critical challenges include overcoming the mathematical representation bottlenecks in fluid-structure interactions of natural flexible vegetation, deeply elucidating the mechanisms of vegetation-wind interactions, and advancing the theoretical development of multi-physics coupling. Addressing these challenges will provide a robust scientific foundation for desertification control, the optimization of eco-friendly windbreak engineering, and ecological restoration in arid and semi-arid regions.

Forest stage classification is a core scientific issue for understanding forest dynamics and implementing sustainable forest management. In response to the challenges of conceptual ambiguity and methodological applicability in current research, this paper systematically reviews and evaluates mainstream classification methods for forest life-cycle stage classification, clarifying their theoretical foundations and application boundaries, so as to provide theoretical basis and practical guidance for precision forest management. The paper first dialectically distinguishes the connotation, difference and connection between the two core concepts of forest succession (species replacement at the community scale) and forest development (structural dynamics at the stand scale), thereby establishing the theoretical cornerstone for the following method review and classification. Furthermore, from the perspective of historical evolution, the paper categorizes existing methods into four major paradigms: 1) Chronological paradigm (age-group classification): with stand age as a single division indicator to serve sustainable timber production, this method is easy to apply, but insufficient to capture complex structures. 2) Structural paradigm (forest cycle stage classification): based on the gap dynamics theory, this method reveals the natural structural cycle of primeval forests and serves as an ecological benchmark for biodiversity conservation. 3) Ecological paradigm (successional stage classification): based on the substitution sequence of functional species groups, this method explains macro-level community succession laws and provides a theoretical framework for ecological restoration. 4) Integrative paradigm (close-to-nature developmental stage classification): oriented toward life-cycle management, combining structural dynamics with management objectives, this method serves as a bridge between ecological theory and management practice. Comprehensive analysis shows that each paradigm has its own historical background, applicable scale, and limitations, thus, the choice of method depends on specific application scenarios or management objectives. Currently, this field faces three core challenges: the complexity of conceptual integration, insufficient quantification and standardization, and the uncertainties introduced by climate change disrupting traditional development and succession pathways. Future research on forest life-cycle stage classification will evolve toward a new phase of deep integration characterized by precision, intelligence, and dynamics. Key development directions include: constructing accurate quantitative indicator systems that integrate structural and ecological functions, developing “climate-smart” dynamic classification frameworks that incorporate climate prediction models. Ultimately, through the deep integration of advanced sensing technologies and artificial intelligence algorithms, a paradigm shift from “manual judgment” to “intelligent perception” is expected, providing transformative technical support for precision monitoring and high-quality management of global forests.

With growing concerns over plastic pollution and climate change, disposable plastic straws have become an important focus of environmental protection due to their high consumption, low recyclability, and lack of biodegradability. Bamboo, as a natural, renewable, and fully biodegradable biomass resource, has emerged as a promising alternative to plastic straws owing to its wide availability, rapid growth, strong carbon sequestration capacity, excellent mechanical properties, and low cost. By preserving the natural structure and tissue of bamboo to the greatest extent possible, the development of bamboo drinking straws can not only enable the production of high-performance products, but also maintain low energy consumption and high material utilisation. Drilled bamboo straws and coiled bamboo straws have become relatively mature products and can be manufactured through automated processes. In the development of drilled bamboo straws, several key innovations have been developed, including high-speed automatic drilling machines, bamboo morphology correction and moisture regulation techniques, as well as chip removal and cooling technologies. For coiled bamboo straws, technological advancements such as slice extension, bamboo flattening and thin slicing, and bamboo strip winding techniques have been developed. These innovations effectively address challenges such as low production efficiency, limited automation, and low product yield, thereby significantly reducing manufacturing costs and enhancing the market competitiveness of bamboo drinking straws. In addition, bamboo straws exhibit excellent mechanical strength, wet stability, and biodegradability. The research and development of bamboo straws fully demonstrate the considerable potential of bamboo valorisation, providing essential technical support and practical examples for the “replacing plastic with bamboo” initiative, and promoting the modernisation, standardization, and industrial-scale development of the bamboo processing industry. The international standard for bamboo drinking straws was officially released by the International Organization for Standardization (ISO 16830) in early 2025. The standard specifies terms and definitions, product classification, technical requirements, testing methods, inspection rules, packaging and labelling, and transportation and storage of bamboo drinking straws. The issuance of this standard strengthens the competitiveness of the bamboo industry and, more importantly, highlights the important role of bamboo in addressing global plastic pollution, reducing dependence on petroleum resources, and advancing green and low-carbon development.