Objective: It is of great significance to clarify the influence of enhanced vegetation activity on evapotranspiration in the southwest alpine and subalpine mountains in order to optimize regional water resources allocation and ensure water resources security. Method: Based on the MOD16 evapotranspiration indicators from 2001 to 2020, including actual evapotranspiration (ET), potential evapotranspiration (PET) and the ratio of actual to potential evapotranspiration (ET/PET), the influence and contribution of meteorological factors such as temperature (T), precipitation (P), relative humidity (RH), pressure (PRS), insolation (I), wind speed (WS) and vegetation factor NDVI on evapotranspiration indicators in the alpine and subalpine area of southwestern China were expounded by linear fitting, SEN trend analysis, partial correlation analysis, stepwise regression analysis and other methods. Result: 1) The peak of ET within one year lagged behind PET, and they showed spatial inconsistency. The annual ET ranged from 246.0 to 1191.3 mm, with the peak occurring late July. The ET was higher in the subalpine section of upper Yarlung Zangbo River and the subalpine area of southern Xizang, and lower in the northern parts of the Nujiang River. Annual PET ranged from 538.0 to 2314.9 mm, with higher values continuing from late May to mid-August. The PET in the southern parts of upper Yalong River and subalpine section of upper Jinsha River was higher. 2) The regional average ET was 627.8 mm, showing a significant increasing trend (P<0.05) at a rate of 2.93 mm·a^?1, and the significantly increased areas were mainly distributed in the upper Jialing River, the upper Min River, the Dadu River, the upper Yalong River, the subalpine section of upper Jinsha River, the upper Lancang River, and part of the Nujiang River. The regional average PET was 1500.6 mm, showing an insignificant decreasing trend at a rate of 2.57 mm·a^?1, and the decreased areas were mainly distributed in the subalpine section of upper Jinsha River, the upper Yalong River, and the subalpine area of southern Xizang. The regional average ET/PET was 0.43, showing a significant upward trend (P<0.05). 3) The order of the main influencing factors for ET was T > P > NDVI > RH > PRS > I > WS, for PET was T > I > P > RH > WS, and for ET/PET was T > RH > NDVI > I > PRS. 4) The increase of ET was mainly caused by the enhanced vegetation activity, and the area dominated by the increase of NDVI accounted for nearly 63%. The decrease of PET was mainly related to the reduced insolation. The positive effects of increasing NDVI and decreasing insolation offset the negative effects of increasing temperature on ET/PET, resulting in the increase of ET/PET. The changing direction of ET/PET in the Budyko model during the study period indicated a shift from water limit to energy limit. Conclusion: The enhanced vegetation activity in the alpine and subalpine area of southwestern China in the past 20 years have had a significant impact on regional evapotranspiration. Our results demonstrate that the long-term sustainability of water balance and soil water supply in the watersheds deserves more attention.

Objective: This study aims to investigate the growth of average tree height and diameter at breast height (DBH) of Larix principis-rupprechtii plantation stands and the growth responses to site factors and stand structure in the small watershed of Diediegou located in the semi-arid area of Liupan Mountains in Ningxia of northwest China, and thereby providing a theoretical basis for tree growth prediction and sustainable forest management. Method: In 2018 and 2019, 42 and 57 sample plots of L. principis-rupprechtii plantations were selected respectively, to investigate the stand structural characteristics (tree height, DBH, forest age, density, etc.) and site factors (slope aspect, soil thickness, etc.). In addition, the data from 93 sample plots surveyed between 2003 and 2017 in the Liupan Mountains were also collected for this study. Based on the data from all these 192 plots, the response patterns of tree height and DBH growth to the influencing factors such as forest age, density, slope aspect, and soil thickness were analyzed, and the growth models of tree height and DBH were established and validated using 2/3 and 1/3 of the dataset. Result: The tree height and DBH exhibited distinct response patterns to forest age, density, slope aspect, and soil thickness. Both tree height and DBH increased rapidly with rising forest age until to 20 years and thereafter increased slowly. With rising tree density, the tree height and DBH initially remained stable, but then decreased gradually after exceeding the thresholds of 2 000 and 1 500 trees·hm⁻² and decreased with accelerated rate after exceeding the thresholds of 3 000 and 2 300 trees·hm⁻², respectively. As the slope aspect deviated more from due north, the tree height and DBH initially remained stable until to the threshold of 80° and thereafter decreased rapidly. With rising soil thickness, the tree height and DBH firstly increased and then stabilized when the soil thickness exceeded 90 and 80 cm, respectively. Based on expressions of three types of forest growth models (multiplicative coupling, site index, site factors) in response of tree height and DBH to forest age, tree density, slope aspect, soil thickness, and site index, the coupling models were established and the model parameters were fitted. The determination coefficients of the three models of tree height were 0.804, 0.902, and 0.806, and the corresponding NS coefficients were 0.793, 0.903, and 0.762, respectively. The determination coefficients for the three models of DBH were 0.846, 0.803, and 0.834, and the corresponding NS coefficients were 0.837, 0.840, and 0.818, respectively. All the three models performed satisfactorily compared with the observed data. Conclusion: In the semi-arid area of Liupan Mountains, the growth of tree height and DBH of L. principis-rupprechtii plantations has different responses to the main influencing factors, i.e., firstly increases quickly and then increases slowly with rising forest age, firstly stabilizes and then decreases with rising tree density and slope aspect, and firstly increases and then stabilizes with rising soil thickness. All the multi-factor coupling models of three types (multiplicative coupling, site index, and site factors) exhibit high accuracy. However, considering the undetermined distribution pattern of the site index, the accuracy differences and application difficulty and structural complexity of models, it is suggested to use the multi-factor coupling model for predicting the tree height and DBH growth of L. principis-rupprechtii plantations in the study region.

Objective: The aim of this paper to analyze the changes in soil microbial community structure and functional group characteristics of poplar plantations at different ages, reveal the impact of stand age on soil microorganisms, and provide a scientific basis for soil fertility maintenance and sustainable management of poplar plantations. Method: Populus×euramevicana ‘I-214’ plantations at ages of 2, 4, 7, 10, and 14 years were selected in Xinmin City, Liaoning Province. The soil physical and chemical properties of the 0?20 cm soil layer were measured, and the high-throughput sequencing technology was used to analyze the differences in soil bacterial and fungal community structures and functional diversity among I-214 poplar plantations of different stand ages. Result: The study showed that the contents of soil organic carbon, nitrate nitrogen, available potassium, and available phosphorus all exhibited a trend of decrease followed by an increase among differents ages. The dominant bacterial phyla in the soil were Proteobacteria and Acidobacteriota, and the relative abundance of Proteobacteria increased with age. The dominant fungal phyla were Ascomycota and Basidiomycota, and their relative abundances were hardly affected by stand age. The Shannon index of soil bacteria first decreased and then increased with stand age, reaching the highest at 2 years old. The redundancy analysis showed that soil bulk density, pH, available potassium and available phosphorus content were the main soil factors that significantly affected soil bacterial communities, while total nitrogen and nitrate nitrogen content were the main soil factors that significantly affected soil fungal communities. Functional prediction of soil microbial communities showed that the relative abundance of bacterial communities involved in carbon and nitrogen transformation increased with age. Conclusion: In the I-214 poplar plantation in the Songliao Plain, the relative abundance of Proteobacteria, the dominant bacterial community in the soil, increased with the increase of age, while the relative abundance of Acidobacteria increased first and then decreased with the increase of age, but the dominant fungal community was hardly affected by stand age. Soil bulk density, pH, available potassium, available phosphorus, total nitrogen and nitrate nitrogen content are the main soil factors affecting soil microbial communities. The relative abundance of bacterial communities involved in soil nitrogen transformation functions such as soil nitrogen fixation and carbon transformation functions such as Phototrophy increased with the increase of age. The Shannon index of soil bacteria, the relative abundance of carbon transformation functional communities, and the nutrient contents of soil nitrate nitrogen, available potassium, and available phosphorus all showed a significant decreasing trend starting from the 10-year-old, indicating that the 10-year-old poplar plantation in the Songliao Plain may be at a critical change point of soil fertility, microbial community structure, and functional diversity. At this stage, it is necessary to consider adopting appropriate management measures to maintain soil fertility, microbial community structure, and functional diversity.

Objective: The aim of this study is to investigate how different stand types affect soil phosphorus availability and to identify the critical inorganic phosphorus fractions that regulate this availability. This research seeks to provide a theoretical foundation for maintaining soil fertility and implementing sustainable management practices in the different plantation soils of Baishanzu National Park. Method: This study took the four types of plantations as objectives, including Chinese fir pure forest, masson pine pure forest, Chinese fir-masson pine mixed forests, Chinese fir-moso bamboo mixed forests. We determined the basic properties, inorganic phosphorus fractions and available phosphorus content of the 0−10, 10−20, and 20−40 cm soil layers, and analyzed the differences of total phosphorus content, available phosphorus content, and inorganic phosphorus fractions among stand types to reveal the key driving factors for the variations in soil phosphorus availability. Result: The total phosphorus and available phosphorus content in the 0−40 cm soil layer across the four stand types were 0.14−0.24 g·kg⁻¹ and 0.73−1.72 mg·kg^?1, respectively, with average values of 0.19 g·kg^?1 and 1.11 mg·kg^?1, respectively. The phosphorus activation coefficient in the 0−40 cm soil layer across the four stand types was 0.42%−0.72%, with an average value of 0.59%. Notably, these values reached their peak in the Chinese fir-moso bamboo mixed forests. The content of each inorganic phosphorus fraction in the 0−40 cm soil layer across the four stand types showed differences, with the Chinese fir-moso bamboo mixed forests having higher values than the other three stand types. Except for occluded phosphate content, the contents of aluminum phosphate, iron phosphate, calcium phosphate, and soluble phosphorus were all significantly positively correlated with available phosphorus content (P<0.01). Standardized major axis analysis revealed that the allometric index for the relationship between aluminum phosphate content and available phosphorus content is significantly below 1.00 (P<0.01). In contrast, the allometric index for iron phosphate content, calcium phosphate content, and soluble phosphorus content in relation to available phosphorus content are all significantly above 1.00 (P<0.01). The random forest analysis identified aluminum phosphate content, hydrolyzable nitrogen content, and total nitrogen content as the most significant regulatory factors influencing available phosphorus content. The partial least squares structural equation model indicated that stand type indirectly enhanced available phosphorus levels by influencing basic soil properties such as total nitrogen content and hydrolyzable nitrogen content, stoichiometric ratios including organic carbon to total nitrogen and total nitrogen to total phosphorus, as well as inorganic phosphorus fractions such as aluminum phosphate content and iron phosphate content. Conclusion: In this study area, while stand type does not have a significant direct impact on available phosphorus, it significantly influences available phosphorus indirectly by modulating nitrogen levels, nutrient ratios, and inorganic phosphorus fractions. Aluminum phosphate emerges as the most critical regulatory factor affecting soil phosphorus availability. Overall, developing mixed coniferous and broad-leaved forests will be a vital strategy for enhancing soil phosphorus availability in the plantation stands of Baishanzu National Park.

Objective: This study aims to investigate the response characteristics and adaptability of three main pine species (Pinus densata, Pinus yunnanensis, and Pinus kesiya var. langbianensis) to regional climate change in Yunnan, for guiding the prediction of forest growth dynamics in southwest China in the context of climate change, and providing a theoretical basis for forest protection and management in this area. Method: According to the standardized dendrochronological methods, tree ring samples were collected in the distribution areas of various tree species to construct tree-ring chronologies. Combined with climate data including temperature, precipitation, and Palmer drought index at each sampling point from 1958 to 2018, response analysis, multiple regression analysis, and moving correlation analysis were used to determine the critical climate factors affecting the radial growth of the three pine species and their differences in response to climate change. Result: The climate at the sampling sites of the three pine species was warming and drying. The key factors limiting radial growth of P. densata were the precipitation in May and the mean temperature in January, which contributed 59.8% and 27.5% to the variance interpretation rate of the regression model. The critical factors limiting radial growth of P. yunnanensis were the precipitation in October, December of the previous year and January, which contributed 38.8%, 15.4% and 25.4% respectively to the variance interpretation rate of the regression model. The critical factors limiting radial growth of P. kesiya var. langbianensis were the precipitation in the current growing season (July), and precipitation in late growing season (September) of the previous year and current year, and their contribution to the variance interpretation rate of the regression model reached 53.8%, 30.9% and 15.3%, respectively. The radial growth of P. yunnanensis trees was more sensitive to drought than that of P. densata and P. kesiya var. langbianensis trees. Warming and drying enhanced the sensitivity of P. densata to temperature and precipitation in early growing season (May), warming and drying weakened the sensitivity of P. yunnanensis to precipitation in early growing season (May) and enhanced the sensitivity to temperature in growing season, and warming and drying weakened the sensitivity of P. kesiya var. langbianensis to mean and maximum temperature in July and enhanced the sensitivity to precipitation in late growing season (September) of previous year. Climate warming caused the response relationship between radial growth of each pine species and climate factors unstable, which occurred during the period of climate change, synchronized with regional climate fluctuations, and had consistency among different pine species. Conclusion: P. densata and P. kesiya var. langbianensis trees have stronger adaptability to droughts than P. yunnanensis trees. Climate warming weakens the promoting effects of temperature on radial growth of P. densata at high altitude. Warming transforms the sensitivity of P. yunnanensis from being sensitive to low precipitation in early growing season to being sensitive to low temperatures in growing season. Climate warming inhibits the promotion effect of sufficient water conditions on radial growth of P. kesiya var. langbianensis in the growing season, and enhances the lag effect of climate factors on radial growth. The response sensitivity of the three pine species to climate factors becomes unstable due to climate warming.

Objective: This study intends to predict the suitable habitat of Huangxin under different environmental scenarios in current and future periods based on the MaxEnt model. The aim is to explore the distribution of Huangxin, provide a scientific basis for the protection and sustainable use of Huangxin and also serves as a reference for the prediction and protection of potential suitable habitats for endangered plants. Method: This study, based on the MaxEnt model and incorporating environmental variable data from the present and future periods (2030s, 2050s, 2070s) , simulated and predicted the potential geographic distribution of Huangxin under different climate scenarios. Through a comprehensive analysis of the environmental factors limiting its spread, we have formulated targeted conservation measures. Result: 1) The area under the curve (AUC) values of all groups in the MaxEnt model were higher than 0.9, indicating high accurate model predictions. 2) Huangxin has a narrow potential suitable area in China, with a total current suitable area of 50 416 km². The high suitable area is only 2 309 km², located in parts of southern and southwestern Guizhou Province. The medium suitable area (14 288 km²) is distributed around the high suitable area. The low suitable area, amounting to 33 819 km², is distributed in central Guizhou Province, Guangxi Zhuang Autonomous Region, Yunnan Province and Sichuan Province. Under future climate conditions, the potential suitable area for Huangxin shows a trend of first expanding and then contracting over the three periods. Among them, the total suitable area could reach its maximum (70 313 km²) in the 2030s under the high forcing (SSP5-8.5) scenario, with an increase of 39% compared to the current total suitable area. 3) The precipitation of the driest month (bio14), altitude (bio20), isothermality (bio3), and annual precipitation (bio12) are the dominant environmental factors limiting the distribution of Huangxin. 4) Under future climate scenarios, the potential suitable area for Huangxin shows a trend of first expanding and then contracting, with a migration direction first northward and then southeastward. 5) Based on the current situation of Huangxin, we propose relevant conservation measures: delineating protected areas in situ within the high suitable range; conducting relevant breeding experiments in potential suitable areas such as western Hubei Province and northeastern Chongqing Municipality to expand its planting area; and establishing a germplasm resource bank. Conclusion: The suitable habitat for Huangxin is relatively narrow, with the medium to high suitable areas predominantly concentrated in southwestern Guizhou Province. Low suitable areas may also be distributed in parts of Guangxi Zhuang Autonomous Region, Yunnan Province, Sichuan Province, Chongqing Municipality, and Hubei Province besides Guizhou Province. The current suitable area for Huangxin has not reached saturation, and it is projected to reach its maximum area in the 2030s. Under future climate scenarios, the area of potential suitable habitats is expected to first expand and then contract. Given the current status of Huangxin, it is recommended to carry out human-assisted measures such as habitat restoration and rapid promotion of population recovery.

Objective: This study aims to investigate the geographical variation of Dendrocalamus brandisii bamboo shoots quality in different planting regions and its relationship with the environment, and analyse the main influencing factors, so as to provide a reference basis for the management of D. brandisii and the improvement of bamboo shoots quality. Method: This study was conducted in seven different planting regions of D. brandisii in Yunnan Province (Mangshi, Simao, Shiping, Xinping, Changning, Linxiang, and Cangyuan). The external morphology and nutritional components of bamboo shoots from each location were measured, and variance, correlation, and redundancy analyses were conducted with site environmental factors such as soil chemical properties, climate, and altitude. Result: 1) There were significant differences in external morphology of D. brandisii bamboo shoots from different regions. The bamboo shoots from Changning had the highest base diameter and shoot length indicators, those from Cangyuan had the highest weight indicator, those from Mangshi had the highest edible portion indicator, and those from Shiping had the highest edible rate. 2) Bamboo shoots from different regions exhibited relatively high moisture content (AW). The tannin (Tan) content of bamboo shoots from Changning was significantly higher than that in other regions; the soluble sugar (SS) content in Mangshi was significantly higher than that in other regions; the crude fat (EE) content in Linxiang was significantly higher than that in other regions; the lignin (Lig), Ash, and protein (Pr) contents in Simao were significantly higher than those in other regions; and the cellulose (Cel) content in Xinping was significantly higher than that in other regions. 3) Correlation analysis showed that there was a significantly negative correlation between base diameter and low temperatures in August; a significant positive correlation between proline (Pro) and August precipitation; a significant positive correlation between arginine (Arg) and available potassium; and a significant positive correlation between Arg and air relative humidity and average temperature in August. 4) Redundancy analysis of environmental factors and D. brandisii shoot quality showed that nutrients in bamboo shoots, such as EE, Arg, His, Ser, Thr, and Pr, were positively responsive to available phosphorus and total phosphorus, while shoot length, weight, and edible portion exhibited a negative response. Shoot length, weight, edible portion, and AW were positively related to air relative humidity and average temperature in August. Nutrients in bamboo shoots, such as Pro, Ala, Tan, Glu, and Met, were positively responsive to August precipitation and negatively responsive to soil organic matter. Asp, SS, and edible rate were positively responsive to soil organic matter and negatively influenced by August precipitation. Conclusion: Among the seven regions, Changning has the best quality of D. brandisii bamboo shoots. The low temperature in August is the main environmental factor affecting the external morphology of D. brandisii bamboo shoots, while air relative humidity and average temperature in August are the main factors affecting the basic nutritional components of bamboo shoots. The amino acid content of D. brandisii bamboo shoots is mainly influenced by available potassium and August precipitation. The external morphology of bamboo shoots is positively correlated with soil organic carbon, air relative humidity, and average temperature in August, while the nutritional components of bamboo shoots exhibit a positive response to available phosphorus, total phosphorus, and August precipitation.

Objective: This study aims to understand the resistance ability of Idesia polycarpa to extreme high temperatures through investigating the physiological response of I. polycarpa seedlings to extreme high temperature stress and combined stress of high temperature and drought, so as to provide a reference and scientific theoretical basis for its cultivation and introduction, as well as for the production and survival under extreme high temperature. Method: In this experiment, 2-year-old I. polycarpa ‘Yuji’ seedlings were used as test material. The temperature and water were controlled in an artificial climate chamber to simulate extreme high temperature, and high temperature plus drought stress environment, with the natural environment served as the control. The I. polycarpa ‘Yuji’ seedlings were subjected to the above conditions and their morphological and physiological changes were measured. Result: Under the extreme high temperature stress and combined stress of high temperature and drought, I. polycarpa ‘Yuji’ seedlings wilted, the branches and trunks crumpled, and the seedlings died. The seedling height, diameter, root length, root surface area, root average diameter, biomass, leaf epidermal thickness, palisade tissue thickness, and spongy tissue thickness were all decreased to different degrees. Photosynthesis (P_n) rate was significantly decreased, stomatal conductance (G_s) and transpiration rate (Tr) gradually decreased, intercellular carbon dioxide concentration (C_i) gradually increased. P_n was mainly limited by non-stomatal factors. In terms of antioxidant system, high temperature stress caused SOD activity first increase and then decrease, high temperature and drought combined stress led SOD activity and POD activity decrease, and both stresses promoted an increase in MDA content. High temperature stress made soluble protein content first rise and then fall, high temperature and drought combined stress led a decrease in soluble protein content, and both stresses caused an increase in soluble sugar content. The effects of the combined stress on morphology and physiology were greater than those of high temperature stress. Conclusion: I. polycarpa ‘Yuji’ seedlings can tolerate the conditions of a daily average temperature of 40.0 ℃, and the daily maximum temperature of 62.0 ℃ for 24 h. If the conditions last more than 24 h, the seedlings will be subject to severe persecution. Both the high temperature stress and the high temperature and drought combined stress seriously affect I. polycarpa ‘Yuji’ seedlings, and the victimization degree caused by the combined stress is greater than that caused by high temperature stress.

Objective: This study aims to explore the growth-promoting characteristics and mechanisms of two screened antagonistic bacteria, Bacillus velezensis BD2231 and Streptomyces mirabilis BD2233, so as to provide effective microbial agents for controlling basal rot of hybrid bamboo and enhancing plant growth. Method: Qualitative and quantitative methods were used to determine the abilities of BD2231 and BD2233 in the secretion of indoleacetic acid, phosphorus solubilization, iron carrier production, biological nitrogen fixation, ACC deaminase production, and cellulase production, and to analyze the effects of the two strains on the germination of tomato and tobacco seeds, as well as on the growth of tomato, tobacco, and hybrid bamboo seedlings. ELISA kits and real-time fluorescence quantitative PCR method were used to investigate the effects of the strains on the concentrations of IAA, GA, SA, and JA and the expression of their related genes in the leaves of tomato, tobacco, and hybrid bamboo. Result: Both BD2231 and BD2233 were able to produce IAA, iron carrier, and cellulase, but did not have the ability of phosphorus solubilization, biological nitrogen fixation, and ACC deaminase production. BD2233 secreted IAA at a concentration of 12.44 mg·mL^?1, and BD2231 achieved the carrier activity unit (SU value) of 26.7% and cellulase activity (CMC enzyme activity) of 0.43 U·mL^?1, respectively. Two strains of biocontrol bacteria significantly promoted the germination of tomato and tobacco seeds, and the germination rates of tomato and tobacco seeds treated with the fermentation broth of strain BD2231 were higher, at 61% and 87%, respectively. In addition, the two strains significantly promoted the growth of hybrid bamboo seedlings and increased the plant height, stem thickness, fresh and dry weight. BD2231 and BD2233 significantly promoted the expression of endogenous hormones, such as IAA, GA, SA, and JA, pathway-related genes IAA9, GA20ox, PR-1, and MYC2 in plant leaves and increased the concentration of endogenous hormones. BD2233 was more effective in improving the concentration of IAA, while BD2231 was more effective in increasing the concentration of GA, SA, and JA in plants. Conclusion: B. velezensis BD2231 and S. mirabilis BD2233 promote plant seed germination and seedling growth through the production of IAA, iron carrier, and cellulase. They can also increase the concentration of IAA, GA, SA, and JA, as well as the expression of their related genes, with BD2231 performing better in promoting plant growth.

Objective: Using the Saihanba Mechanized Forest Farm as a case study, a forest fire risk zoning method based on forest combustible characteristics was established, providing a reference for fire risk zoning at the forest farm scale. Method: 15 fire risk influencing factors were selected, The analytic hierarchy process (AHP), expert scoring, and judgment matrix methods were used to derive the factor weights for ignition danger, fire intensity danger, and comprehensive fire risk at the plot scale. Based on plot survey data and determination of the combustible physical and chemical properties, the ignition danger index, fire intensity danger index, and comprehensive fire risk index for each plot were calculated. Cluster analysis and ArcGIS technology were used to generate zoning maps for ignition danger, fire intensity danger, and comprehensive fire risk within the forest farm, and to analyze the fire occurrence risk within the forest farm area. Result: 1) In the Saihanba Mechanized Forest Farm, the area of the extremely high ignition danger (V_Y) level accounts for 9.21% of the total area of the forest farm, mainly scattered in the west, south, and central parts of the farm; the high (Ⅳ_Y) and moderately high (Ⅲ_Y) levels have a wider distribution, with presence throughout the study area; The combined area of the higher than high levels (Ⅲ_Y, Ⅳ_Y, V_Y) accounts for 67.95%. 2) The area of the extremely high fire intensity danger (V_Q) level is the largest, accounting for 46.42% of the total area of the forest farm, followed by the high level (Ⅳ_Q), which accounts for 26.38%; the sum of the two levels is 72.8%, mainly concentrated in the south and west of the forest farm; the higher level (Ⅲ_Q) accounts for 7.95% of the farm area, mainly distributed in the east. 3) The area of the high (Ⅳ_Z) and moderately high (Ⅲ_Z) comprehensive fire risk levels is large, accounting for 29.07% and 28.12%, respectively; the extremely high level (V_Z) accounts for 19.13%; the moderately high and higher levels (Ⅲ_Z, Ⅳ_Z, and V_Z) collectively account for 76.32% of the total area, mainly distributed in the west, south, and central parts of the forest farm. Conclusion: The fire risk zoning method established in this study, based on the AHP, cluster analysis, and ArcGIS technology, can effectively classify forest fire risk at the plot scale, generating zoning for ignition danger, fire intensity danger, and comprehensive fire risk, and is a valuable reference for the management of combustible materials at the forest farm level. The comprehensive fire risk level in the Saihanba Mechanized Forest Farm is very high, especially in the west, south, and central parts of the forest farm; the area of the extremely high (V_Q) and high (Ⅳ_Q) fire intensity danger levels is extensive, and once ignited, it is highly likely to cause high-intensity forest fires. The areas with high ignition danger and high fire intensity danger do not completely overlap. It is essential to strengthen fire source management and the management of flammable and combustible materials in areas with high ignition danger to reduce the probability of fire occurrence. In addition, the implementation of isolation belts located between areas with high fire intensity danger and high ignition danger is recommended to effectively prevent the rapid spread of potential fires to areas with high fire intensity danger, and to control the occurrence of large-scale disasters.

Objective: This paper was aimed to model and grade the risks of forest fires threatening the buildings in the wildland-urban interface, in order to provide scientific evidences for rational planing of urban fire protection and appropriate allocation of firefighting resources in the WUI. Method: Based on fire behavior analysis, the intensity of thermal radiation and the quantity of flying particles generated by fire. By coupling the flame length model, the flame tilt angle model, the thermal radiation model and the fire particle flux model, a method is proposed to grade the risks of fire threatening the WUI buildings using three indicators: thermal radiation, flying fire particles, and the importance of the buildings. The WUI fire risks are divided into three categories using an assignment method, each with corresponding adjective ratings. The importance of the input parameters in the thermal radiation model and the fire particle flux model are ranked by local sensitivity analysis. The level of thermal radiation and fire exposure is graded in terms of the spacing. Finally, a case study of Uljin County of Korea was conducted, the risk level of buildings is analyzed. Result: By literature review on the available experimental data, the thermal radiation exposure of buildings are categorized into three levels: 0?9, 9?30, ≥30 kW·m⁻². The fire particle exposure of building is also divided into three levels: 0?2, 2?3, ≥3 pieces. The importance of buildings is graded into four levels by its effects on human life, economy, society and environment. A risk model is developed for buildings threatened by forest fire. The risk levels are graded into high, moderate, and low levels based on the severity of the danger, and specific characteristics are provided for each risk level. Using the new model, the damage to a 400 m² single-story Class B factory in Uljin County, by a fireline intensity of 5 000 kW·m⁻¹, under the wind speed of 2 m·s⁻¹ and the spacing of 10 m, is graded as moderate. Conclusion: By local sensitivity analysis, the importance of the parameters of the thermal radiation model and the fire particle flux model is ranked from high to low as the flame temperature, spacing between fireline and building, atmospheric transmissivity, flame emissivity, fireline intensity, and wind speed. The maximum radiant thermal flux and the quantity of fire particles, received by buildings in WUI, decrease with the increase of spacing, but increase with the increase of wind speed and fireline intensity.

Objective: Weak spectral signals induced by pest and disease stress are often obscured by spectral variations caused by vegetation phenology. This study investigates a forest pest and disease monitoring method that enhances weak spectral signals related to vegetation stress, aiming to provide a scientific basis for the prevention and management of forest pests and diseases. Method: Illicium verum was selected as the study species, with Leye County in the Guangxi Zhuang Autonomous Region designated as the experimental area. Sentinel-2 imagery data from 2019 to 2021 were collected for this region. Initially, six vegetation indices sensitive to pest and disease stress responses were selected as preliminary indicators for Illicium verum pest and disease stress: the normalized difference vegetation index (NDVI₇₀₅), red edge position index (REPI), chlorophyll reflectance red-edge index (CI_red-edge), plant senescence reflectance index (PSRI), pigment-specific simple ratio chlorophyll index (PSSRA), and fraction of absorbed photosynthetically active radiation (FAPAR). The Savitzky-Golay (S-G) filtering method was then employed to construct time series curves of these spectral indices. PSRI and FAPAR were identified as the most effective indices for comprehensively characterizing morphological color and physiological changes induced by pest and disease stress in Illicium verum. The Seasonal-Trend decomposition using LOESS (STL) method was applied to decompose the time series of FAPAR and PSRI indices, allowing for the isolation of seasonal components. This facilitated the construction of the Illicium verum Pest and Disease Index (IPDI) by integrating the seasonally adjusted FAPAR and PSRI components. Finally, a monitoring model for pest and disease stress in Illicium verum was developed using the Random Forest algorithm. Result: 1) Compared to healthy vegetation, Illicium verum plantations under pest and disease stress exhibited lower FAPAR and higher PSRI values. 2) The STL method effectively isolates the influence of phenological changes on parameters sensitive to vegetation stress from pests and diseases, thereby enhancing the sensitivity of Illicium verum to stress detection. 3) The remote sensing identification model based on IPDI demonstrated high accuracy, with kappa coefficients and overall accuracies from 2019 to 2021 of 0.81, 0.84, and 0.80, and 87.59%, 88.51%, and 84.17%, respectively. In 2020, the relative error between the remote sensing-calculated damage area of Illicium verum and the statistical disaster area was 2.08%. Conclusion: The method based on enhancing weak spectral signals from vegetation stress effectively monitors the distribution of pest and disease stress in Illicium verum forests. This approach significantly improves control efficiency and supports the sustainable management and ecological conservation of these forests.

Objective: To predict the latest potential suitable areas of Monochamus alternatus in China and its responses to climate change, so as to a theoretical basis for the risk analysis and the precise prevention and control of M. alternatus in China. Method: Based on the latest 650 occurrence data of M. alternatus and 20 environmental factors, the optimized MaxEnt model and ArcGIS 10.7 software were used to predict the current and future potentially suitable areas of M. alternatus in China under different climatic conditions. Result: The results of model optimization show that when the feature combination of LQHP (linear, quadratic, hinge, product) is selected and the regularization multiplication is set to 1.5, the model is the optimal one with the highest accuracy. The Jackknife shows that the monthly mean temperature difference, annual precipitation, precipitation of driest month, precipitation of warmest quarter and elevation were the dominant bioclimatic variables affecting the distribution of M. alternatus. Under the current climate scenario, the suitable areas of M. alternatus in China are mainly distributed in the areas south of the Yellow River. Under the future climate scenarios, there is a significant increase trend for the potentially suitable areas of M. alternatus, and the newly added areas are mainly concentrated in Shaanxi, Henan, Gansu, Shandong and Liaoning Province. Conclusion: The optimized MaxEnt model can accurately predict the distribution of M. alternatus in our country. Temperature and precipitation are the main environmental factors affecting the distribution of M. alternatus. Climate change will cause the migration of suitable areas of M. alternatus.

Objective: A furfuryl alcohol (FA)- epoxidized vegetable oils (EVO) composite modification method was used to improve the problem of FA modification reducing the toughness of wood and to promote its application in the field of building structures. Method: Two kinds of EVO, epoxidized soybean oil (ESO) and epoxidized linseed oil (ELO), were compounded with FA solution in different additive amounts to prepare impregnation solution, and the FA-EVO composite modified wood with different EVO additives was obtained by treating the wood of poplar (Populus tomentosa) with the full-cell method. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) were utilized to investigate the distribution pattern of FA and EVO in the cell structure of the wood and to reveal their chemical reaction relationship. The mechanical property changes of composite modified wood were analyzed, and the appropriate toughening agent addition amount was optimized. Result: The observation of SEM of the composite modified wood, combined with the results of its weight gain rate and density test (significant increase), proved that the FA resin and EVO impregnated into the cellular structure of the wood. The ring opening reaction of FA with EVO was revealed by FTIR analysis. Compared with the FA modified wood, the tangential swelling and volumetric swelling of air-dry, tangential swelling and volumetric swelling of water-saturated of FA-ESO composite modified wood with addition of 20% (additions are mass fractions, same below) ESO decreased most by 36.9%, 20.0%, 35.9%, and 30.7%, respectively, and the greatest coefficient of the anti-swelling efficiency (ASE). When the addition of ELO was 40%, these indicators decreased most by 52.5%, 65.6%, 41.5%, and 46.0%, respectively, and the greatest coefficient of the ASE. The incorporation of EVO significantly improved the dimensional stability of FA modified wood. Compared with the FA modified wood, the modulus of rupture (MOR) of the composite modified wood increased most by 17.9% and 25.3%, respectively, and the static hardness increased by 30.0% and 25.1%, respectively, when the addition of ESO and ELO was 20%. When the addition of ESO and ELO was 40%, the modulus of elasticity (MOE) of the composite modified wood increased most by 22.7% and 21.1%, respectively. Compared with other mechanical properties, EVO improved the toughness of FA modified material the most. When ESO and ELO were added at 40%, the impact bending strength of the composite modified wood was increased by 88.7% and 59.8%, respectively. The addition of EVO can significantly increase the MOE, MOR and static hardness of FA-modified wood, and improve their toughness degradation. Conclusion: By analyzing the significant differences in the properties of dimensional stability, MOE, MOR, static hardness and impact bending strength of FA-EVO composite modified wood with different addition amount of EVO, the physical-mechanical properties of the composite modified wood were optimal when the addition amount of EVO was 20%. EVO and FA have a ring-opening reaction, and its long aliphatic chain is introduced into the FA resin chain to make up for the defects of the reduced toughness of the FA modified wood, and further improve its physical and mechanical properties, which promotes its application in the field of building structure.

Objective: Directional recombinant technology was used to prepare Cupressus funebris scrimber, the structure and performance were analyzed, so as to reveal the internal causes of the performance changes of cypress wood after it is prepared into scrimber, and provide technical references and theoretical basis for the high-value utilization of cypress wood in plantation forests. Method: Different compression rates (80%, 100%, and 120%) were adopted to prepare C. funebris scrimbers, and subsequently the effect of preparation process and compression rates on the water resistance and mechanical properties (bending properties and horizontal shear properties) of C. funebris scrimbers were investigated. Ultra-deep field microscopy (UDM), cold field emission scanning electron microscopy (SEM), laser confocal microscopy (LSM), and transmission electron microscopy (TEM) were used to observe the microstructural changes and glue distribution of scrimber. Also, the vertical profile density of scrimber was studied by profile densitometry. Result: As the compression rates of scrimber increased, the surface color deepened, the profile density more uniform, the water absorption rate (WAR), thickness swelling rate (TSA), and width swelling rate (WSA) gradually decreased, and the modulus of rupture (MOR) and horizontal shear strength (HSS_⊥) gradually increased. The WAR of scrimber was the lowest at a compression rate of 120%, which was 34.73% lower than that of C. funebris. The maximum MOR and HSS_⊥ were 125.77 and 17.05 MPa, respectively, which were 53.47% and 84.32% higher than those of C. funebris. The result of profile density, SEM, LSM, and TEM showed that the improvement of water resistance and mechanical properties of the scrimber was mainly due to the compression denseness of wood cells, the wider distribution of glue, in addition, gluing sites formed by the phenol-formaldehyde resin (PF) among more cells enhanced connections of cell lumen and middle lamella, thus reducing the water entering channels during water absorption, inhibiting the rebound of cell cavities and strengthening the weak structure of middle lamella. Conclusion: The C. funebris can be prepared into scrimber with significantly improved mechanical properties by directional recombination technology, in which water resistance increased with the increase of compression rates. The performance reached the best when the compression rate was 120%.

Objective: By analysing the technical parameters and cutting effect of laser cutting Fraxinus mandshurica, the optimal regression equation model of cutting effect was established to provide a theoretical basis for estimating the cutting effect. Method: Taking the technical parameters of the laser machine lens height, cutting speed and light intensity as the influencing factors, and the seam depth and seam width as the cutting effect indicators, the two were analysed by Spearman correlation analysis using SPSS 27.0 software, and further multivariate linear and non-linear regression analyses were carried out by using MATLAB R2020a software programming based on the principle of the least squares method. Result: 1) The lens height was significantly correlated with the seam depth and width, with correlation coefficients of −0.677 and 0.962, indicating that the lens height was negatively correlated with the seam depth and positively correlated with the seam width. The cutting speed was significantly correlated with the seam depth and not with the seam width, with correlation coefficients of −0.619 and −0.090, indicating that the correlation was negatively correlated with the seam depth and seam width. The light intensity was not significantly correlated with the seam depth and seam width, with correlation coefficients of 0.116 and 0.057, indicating a positive correlation with the seam depth and seam width. 2) Linear regression analysis showed that the goodness-of-fit R² of the regression model for seam depth was 0.771 54 (P<0.01). The goodness-of-fit R² of the regression model for seam width was 0.904 58 (P<0.01). Non-linear regression analyses yielded a goodness-of-fit R² of 0.936 69 (P<0.01) for the regression model of seam depth. The a goodness-of-fit R² of 0.942 41 (P<0.01) for the regression model of seam width. Both multivariate linear and non-linear regression models were well fitted, but the accuracy of the multivariate nonlinear regression model was relatively higher than that of the multivariate linear regression model. 3) From the comparison of the coefficients of the multiple regression model equations and the magnitude of the image changes, it can be obtained that the influence of the lens height on the seam depth and width is greater than that of the cutting speed and light intensity. 4) In the actual laser cutting Fraxinus mandshurica production, if the values of seam depth and seam width are only roughly and quickly calculated, the multiple linear regression model can be used for estimation; on the contrary, if the values of seam depth and seam width are calculated more accurately, the estimation effect will be better if the multiple nonlinear regression model is used for estimation. Conclusion: 1) Seam depth and seam width generally show a periodic change law with the combination of laser technical parameters. 2) In the production of laser cutting Fraxinus mandshurica, it is necessary to adjust the lens height first. 3) The influence of the combination of laser parameters on the seam depth and seam width shows more significant non-linear characteristics.

Enabling technology in the process of intelligent manufacturing is an effective way to accelerate the transformation of furniture intelligent manufacturing and rapidly improve the high-quality development of the furniture industry. This work summarizes the fundamental theory, basic technology research, and application on furniture intelligent manufacturing in the past 30 years, and identifies the enabling technologies and implementation strategies needed for high quality development. On the one hand, two major technical systems are proposed: basic and process technology innovation, frontier and enabling technology for high-quality development of furniture intelligent manufacturing. This work has built an intelligent manufacturing technology system platform for high-quality development, including: overall architecture, core objectives and content, theoretical breakthroughs and basic guarantees, enabling technologies, new development models, implementation strategies, etc. The system is constructed from the aspects of theoretical breakthrough, basic guarantee, basic and process technology innovation, and new enabling technology, and the high-quality development goal of high-quality, efficient, low-consumption, green and safe furniture is set. It defines the core contents of five aspects of intelligent furniture products, intelligent production, intelligent factory, intelligent logistics and intelligent service, and puts forward the ideas of accelerating basic and process technology innovation such as automatic data collection and processing, information integration, industrial Internet/Internet of Things, modeling and simulation, etc. It also expounds the application scenarios of new technologies composed of big data technology, industrial robot technology, intelligent scheduling and control technology, virtual reality and augmented reality technology, and interprets the implementation methods of cutting-edge technologies such as cloud computing and edge computing, digital twin, artificial intelligence, and software-defined. On the other hand, the technical system is summarized, including: the technical system built by the furniture information control platform, the digital technology system based on the whole life cycle of furniture products, and technical system for sustainable development of furniture intelligent manufacturing. Finally, future research proposals are put forward for the high-quality development of new-generation intelligent manufacturing technologies in furniture enterprises: reshaping the enterprise development model by combining the digital integration model of the whole life cycle, the connected factory model, and the business model of home products; using data-driven, software-defined, virtual-real combination and systemic connection to strengthen the implementation of new strategies.

Objective: The aim of this study is to clarify the pollen morphology and pollen germination methods in vitro of three Syringa species, compare the effects of different storage temperatures on pollen viability, and estimate the pollen/ovule ratio (P/O) and out crossing index (OCI), so as to provide reference for cross breeding of Syringa. Method: S. oblata, S. oblata var. alba and S. × persica were used as experimental materials, and the pollen morphology was observed using scanning electron microscopy. In vitro culture methods were used to study the suitable media for pollen germination, and the effect of different storage temperatures on pollen lifespan was explored. A blood cell counter method was used to calculate the P/O ratio and the out crossing index was estimated through measuring flower traits. Result: All three Syringa species had medium sized pollens, ellipsoidal in shape, with three germination grooves and clear network carvings. The ratio of pollen polar axis length to equatorial axis length (P/E) value ranged from 1.45 to 1.83, and the volume index ranged from 28.24 to 38.82. The contents of sucrose, boric acid, CaCl₂, GA₃, and 6-BA in the culture medium all had effects on pollen germination in vitro. The suitable medium composition for the pollen germination of three Syringa species was as follows: 15 g·L⁻¹ sucrose, 50 mg·L⁻¹ boric acid, 50 mg·L⁻¹ calcium chloride, and 25 mg·L⁻¹ 6-BA for S. oblate, 15 g·L⁻¹ sucrose + 50 mg·L⁻¹ boric acid + 50 mg·L⁻¹ calcium chloride + 50 mg·L⁻¹ GA₃ for S. oblata var. alba and S. × persica. Conclusion: According to the number, position and character (NPC) system of pollen classification, the pollen of all three Syringa species belongs to the N3P4C5-type, which can be identified based on pollen volume, P/E ratio, and extine pattern of pollen. The viability of pollens stored at room temperature can only be maintained for about 14 days. The pollens stored at –80 ℃ maintains high pollen viability, making it the optimal method for preserving pollens. The P/O ratio estimation suggests that the three Syringa species have outcrossing breeding system, whereas the OCI results suggest that the breeding modes of the three Syringa species are partial self-compatible, insect-pollination outcrossing.

Objective: The objective of this study is to breed Camellia oleifera cultivars with high yield, stable yield, strong stress resistance and suitable for mechanized cultivation, so as to provide a new generation of improved cultivars for the high-quality development of C. oleifera industry. Method: In the early and middle 1980s, 14 elite clones of C. oleifera were selected from Chaling County, Hunan Province, the central producing area of C. oleifera, and a total of 84 clonal comparison test forests were established combined with 70 selected elite clones of C. oleifera from all over the country. The experimental design was 10 plants per plot and three replicates. After 2006, the production was continuously measured and the economic traits were evaluated on each clone for 3 years. Result: In 2008, three large-fruited C. oleifera varieties, namely ‘Huaxin’, ‘Huajin’ and ‘Huashuo’, were selected from 84 elite clones, all of which originated from Chaling. Compared with other clones, these varieties had larger fruits, higher yields, stable yields, stronger adaptability, lower production cost, and were easy to identify, and suitable for mechanized harvesting, with simple and efficient variety allocation. Conclusion: In 2009, the three C. oleifera varieties of ‘Huaxin’, ‘Huajin’ and ‘Huashuo’ passed the approval of national forest cultivars committee, and in 2021, they passed the approval of planting expansion scope, and were listed as among 16 main recommended cultivars of C. oleifera by the National Forestry and Grassland Administration. Now they have been widely applied in Hunan, Jiangxi, Guangxi, Guangdong, Hubei, Henan, Sichuan provinces, municipalities or autonomous regions, which has effectively promoted the upgrading of C. oleifera cultivars and the high-quality development of the industry in China.