To meet the strategic demands of high-quality forestry development and to support ecological restoration, timber supply, and carbon sequestration, forest tree genetics and breeding plays a central role in linking germplasm innovation, elite variety cultivation, and industrial application. In recent years, research on forest genetic breeding in China has increasingly focused on frontier fields such as genomics, precision gene editing, and molecular design breeding. Key technologies have continued to break through, and the integration of complementary approaches and the formation of a full chain innovation pattern have accelerated, significantly improving breeding accuracy and efficiency and providing core technological support for forestry modernization. In 2025, a series of significant progress in China has been made in forest tree genomics, regulatory mechanisms of major traits, molecular breeding technologies, and elite variety propagation. This review systematically summarizes major research achievements of China in 2025, covering genome assembly and cross-species genomic analyses, the genetic architecture and regulatory mechanisms of key forest traits, advances in gene editing and genomic selection, and innovations in germplasm resources and efficient propagation technologies. Collectively, these studies not only expand current understanding of forest tree genetics, but also provide methodological and resource support for precision design breeding. Finally, we discuss future development directions, with an emphasis on data-driven breeding, intelligent breeding design, the integration of emerging technologies, and the development of integrated breeding frameworks.

Objective: As a key component of forest evapotranspiration, tree transpiration is primarily regulated by environmental factors such as meteorological conditions and soil moisture. However, its response patterns to these factors exhibit significant differences across temporal scales. A thorough understanding of these dynamics can provide support for the scaling-up estimation of field measurements and the precise regulation of forest-water relationships. Method: A continuous monitoring of stem sap flow dynamics was conducted in a Larix gmelinii var. principis-rupprechtii plantation in the Xiangshuihe small watershed of the Liupan Mountains, Ningxia, during the 2023 growing season (May to October). Concurrently, environmental factors and canopy leaf area index (LAI) were observed. The responses of tree transpiration to the main influencing factors were analyzed at hourly, daily and monthly scales. A multi-factor transpiration model was established, and the relative contribution rates of each factor to tree transpiration were further quantified. Result: 1) Both daily and hourly tree transpiration rate showed a saturated exponential relationship with solar radiation (R_s) and vapor pressure deficit (VPD). However, the threshold values of R_s and VPD at which daily transpiration began to slow were approximately one-third of those at the hourly scale. Additionally, daily tree transpiration exhibited a saturated exponential relationship with relative extractable soil water (REW) and an “S”-shaped logistic curve in response to LAI. 2) By coupling these response functions and calibrating them with measured data, the hourly scale transpiration model was able to predict hourly transpiration of trees by meteorological factors (R²=0.80), and the daily transpiration model was able to predict daily transpiration of trees by meteorological factors, REW and LAI (R²=0.83). 3) Analysis of transpiration contribution rates from hourly and daily forest transpiration models revealed distinct patterns: On sunny days, VPD was the dominant factor affecting hourly transpiration variations. During cloudy and overcast conditions, VPD was the primary factor affecting hourly transpiration variations at night and morning, while R_s became the dominant factor affecting hourly transpiration variations from noon to afternoon. On rainy days, VPD was the main contributor at night and R_s during daytime. At the monthly scale, LAI was the dominant factor affecting transpiration changes at the beginning (May), end (October), and peak growth season (July-August) of the growing season, whereas meteorological factors took the lead in June and September. The relative contribution rate of REW remained relatively low throughout all months. Conclusion: This study establishes a multi-factor coupling model integrating hourly tree transpiration responses (R_s and VPD) with daily transpiration responses (R_s, VPD, REW, and LAI). The model effectively predicts hourly and daily transpiration patterns, revealing that the combined effects of the same factors on transpiration do not simply add up across time scales. These findings contribute to a deeper understanding of the temporal scale differences in the response of forest transpiration to dominant factors and provide a theoretical basis for precise forest-water management. For example, in small-scale plantation tending practices, the control of different dominant environmental factors should be considered based on the target temporal scale.

Objective: This study aims to investigate the dynamic changes of soil active microbial communities in different wetland vegetation types under winter low-temperature stress, in order to elucidate the microbiological mechanisms that maintain key ecological functions (cellulose degradation) of wetland ecosystems under low-temperature conditions. Method: Soil samples were collected from Typha orientalis and Iris tectorum fields in November 2021 (before low-temperature stress), January 2022 (during low-temperature stress), and March 2022 (after low-temperature stress relief) during winter and spring. RNA was extracted for high-throughput sequencing, and cellulase activity was determined using the 3,5-dinitrosalicylic acid (DNS) colorimetric method. Resistance and resilience of active microbial communities to low-temperature stress were calculated. Two-way ANOVA, regression analysis, network analysis, heatmap analysis, and random forest models were used to reveal the effects of temperature and vegetation type on active microbial communities and cellulase activity, and to identify the microbial taxa that most influenced enzyme activity. Result: 1) Temperature significantly affected the richness of soil active microbial communities (P < 0.001), and different dominant microbial taxa exhibited distinct response strategies. Proteobacteria and Bacteroidota showed high resistance to low-temperature stress, while Acidobacteriota, Actinobacteriota, Cyanobacteria, Firmicutes, Nitrospirota, and Planctomycetota showed low resistance. 2) There was no significant difference in soil microbial community richness between T. orientalis and I. tectorum fields, but the soil active microorganisms in the I. tectorum field showed higher resistance and resilience to low-temperature stress, and its microbial co-occurrence network was more complex. 3) Soil cellulase activity was significantly affected by soil temperature (P < 0.01), but showed no significant difference between vegetation types. Random forest model analysis indicated that Acidobacteriota was the most important microbial taxon affecting cellulase activity. Conclusion: Low-temperature stress is a key factor affecting active microbial communities, while vegetation can improve the adaptability of active microbes to low-temperature stress by enhancing the stability and interspecific interactions of microbial communities. Proper vegetation allocation is beneficial for maintaining wetland ecosystem functions under low-temperature conditions.

Objective: This study aims to investigate the effects of different fertilization treatments on the growth and wood quality parameters of Chinese fir (Cunninghamia lanceolata), thereby providing a theoretical basis for cultivating high-quality large-diameter timber and achieving sustainable forest management. Method: Based on a long-term fertilization experimental platform for Chinese fir plantations, four treatments were set up: control, nitrogen application alone (100 kg·hm^?2 a^?1), phosphorus application alone (50 kg·hm^?2 a^?1), and combined application of nitrogen and phosphorus (100 kg·hm^?2 a^?1 N + 50 kg·hm^?2 a^?1 P). The fertilization experiment was initiated in 2012, with fertilizers applied four times annually (in March, June, September, and December, at proportions of 30%, 30%, 20%, and 20%, respectively). Nitrogen and phosphorus fertilizers were applied in the forms of ammonium nitrate and sodium dihydrogen phosphate, respectively, mixed uniformly with river sand. Tree-ring analysis was employed to measure annual ring width and latewood rate for each year from 2011 to 2023. The responses of growth and wood property indicators to long-term fertilization were analyzed based on the inter-annual coefficient of variation (CV) of ring width and latewood rate, along with fertilization effect values. The piecewise linear regression and mixed-effects models were used to identify the impacts of fertilization duration and tree diameter class on these indicators. Result: 1) Compared to single-nutrient applications, the combined application of the N+P dampened the interannual fluctuations in ring width and latewood rate caused by extreme drought, buffering tree growth sensitivity and yielding wood uniformity comparable to the control. 2) Under the N+P treatment, the cumulative promoting effect on growth peaked after four consecutive years of fertilization, resulting in a 31.8% increase in cumulative ring width compared to the control. Concurrently, the decrease in cumulative latewood rate was more moderate than that under the P-alone treatment and remained similar to the control levels. 3) The N+P combination alleviated competition among trees of different diameter classes, promoted overall stand growth, and effectively suppressed the diameter class differentiation phenomenon induced by single-nutrient fertilization. Conclusion: It is recommended to implement a combined nitrogen and phosphorus application regimen on a four-year cycle in mid-aged C. lanceolata stands. This approach aims to enhance growth rates while ensuring uniformity in wood texture and maintaining hardness.

Objective: In this study, the degradation degrees of archaeological wood samples of three typical compartments of the “Nanhai Ⅰ” shipwreck was tested and analyzed by multi-dimensional testing methods, aiming to scientifically evaluate their preservation condition and provide theoretical basis and technical support for the protection and restoration of the shipwreck. Method: The representative cabins 4, 7 and 11 of the “Nanhai Ⅰ” shipwreck were targeted, and the systematic monitoring and analysis was conducted in 2023 and 2024. A total of 41 archaeological wood samples were collected from 30 monitoring sites for 5 types of shipwreck components. Optical microscopy was used to identify tree species, and the anatomical features of wood degradation were systematically observed. The maximum water content (MWC) and basic density (BD) of the wood samples were measured. Attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR) was used to obtain the chemical structure information of archaeological wood samples, and principal component analysis (PCA) was applied to process the ATR–FTIR spectral data. Result: The materials for the selected components of the “Nanhai Ⅰ” shipwreck were mainly hardwood pines (Pinus sp.), accounting for 62%. The shipwreck timber from three cabins exhibited similar degradation conditions. The wood degradation progressed from the surface inward, yet exhibited various degradation characteristics across different cabins and monitoring points. Specifically, the wood preservation condition at monitoring points A3 and A6 in cabin 4 remained relatively stable, while point A12 showed a notable difference in the hemicellulose/lignin ratio (H/L) between 2023 and 2024, indicating pronounced degradation of polysaccharide components at this site. In cabin 7, monitoring points A23 and A33 exhibited new enhancement peaks in the wood, with a significant increase in H/L values. With the desalination cleaning of the ship, the wood was less affected by external pollutants, and its preservation condition improved compared with 2023. At point A30, after the removal of exogenous pollutants, the preservation condition remained stable. In cabin 11, points A52 and A58 maintained stable preservation conditions, whereas point A48 displayed reduced absorption peak intensities at 1 725 cm^-1 and 1 645 cm^-1, indicating degradation in the wood. Conclusion: The wood preservation condition of the “Nanhai Ⅰ” shipwreck is poor and is primarily in a moderate to severe state of degradation. There are differences in preservation condition of wood in different compartments or different monitoring sites in the same compartment. Monitoring sites with serious degradation, such as A12 and A48, need to strengthen protection measures, and other sites affected by exogenous substances, such as A23 and A33, need to carry out systematic cleaning and dynamic monitoring.

Objective: Global warming and the increasing frequency of extreme weather events have resulted in lightning-ignited forest fires with larger scale, higher intensity, and stronger destructiveness. This study investigates the spatiotemporal distribution and clustering evolution of lightning-ignited forest fires in the Daxing’anling Mountains, so as to provide a scientific basis for the prevention and management of lightning-ignited forest fires. Method: Based on historical records of lightning-ignited forest fires in the Daxing’ anling Mountains from 2013 to 2024, this study comprehensively applied statistical analysis, two-dimensional Gaussian kernel density analysis, and the geographical detector method to analyze the dynamic evolution patterns, spatial clustering characteristics, and explanatory power of key driving factors. Result: 1) A total of 791 lightning-ignited forest fires occurred during the past 12-year period, showing an overall fluctuating trend with a peak occurring in 2019. These fires were mainly concentrated between April and October, particularly during the spring fire prevention period and the summer growing season, with the earliest event on April 24 and the latest one on September 19. After the spring fire prevention period, the number of fires declined but rose again to a peak in mid-July. The period from 13:00 to 17:00 (excluding 17:00) was the high-incidence time, accounting for more than 50% of the events. 2) Spatially, lightning-ignited forest fires were significantly clustered in the northwestern of study area. Annual analysis revealed interannual variations in cluster locations. Using the natural breaks method, kernel density values were classified into five risk levels, with the southern region generally identified as very low-risk zones (only a few events occurred in 2022). The Getis-Ord Gi^* significance test confirmed that high-risk areas had stable spatial clustering characteristics. 3) The three-day mean temperature before a lightning-ignited fire, monthly maximum temperature, elevation, monthly mean temperature, 0?7 cm soil layer soil moisture, and normalized difference vegetation index (NDVI) were identified as the core driving factors with the strongest explanatory power across different years. Combinations such as relative air humidity and monthly mean temperature (which showed higher explanatory power nine times), as well as elevation and NDVI (seven times), generally exhibited strong explanatory power across the years, indicating that they have a significant influence on the occurrence of lightning-ignited fires. Moreover, the combinations of monthly mean temperature, monthly maximum temperature, and elevation with other factors also demonstrated high explanatory power. Conclusion: This study summarizes the recent occurrence trends and characteristics of lightning-ignited fires in Daxing’anling Mountains, which show overall fluctuating patterns over time. It is recommended to strengthen fire prevention efforts in summer in key forest areas, particularly around 14:00. Lightning-ignited fires in the Wuma, Yong’anshan, Tuqiang and Amur regions have exhibited persistent and significant clustering during the past 12-year period, although in certain years (e.g., 2015 and 2018) the fire events were more scattered and random, showing no significant clustering. The interactions vary among different factor types, with meteorological interactions being particularly prominent and playing a dominant role in the mechanism of lightning-ignited fire occurrence. This study reveals the spatiotemporal evolution patterns and key driving mechanisms of lightning-ignited forest fires, providing scientific basis for more refined and region-specific forest fire prevention and management strategiess.

Objective: The aim of this study is to explore the effects of tree species diversity on intraspecific, interspecific, and total competition intensity in natural Pinus massoniana forests, so as to provide a scientific basis for establishing coordinated interspecific relationships in P. massoniana forests. Method: The natural P. massoniana forests in Ganzhou City, Jiangxi Province was targeted, and three tree species diversity indices, including Patrick richness, Shannon-Wiener diversity, and Pielou evenness, were divided into low, medium, and high levels. The eight-neighborhood translation method was used to select the objective trees, the Voronoi diagram method was used to determine the competition range of the trees, and the Hegyi competition index (CI) was used to calculate the intraspecific and interspecific CI of different diameter classes. The CI across different tree species diversity levels and their relationships with DBH of the objective trees were compared and analyzed. Result: 1) Across the three tree species diversity indices (from low to high), the dominant species remained largely unchanged, primarily consisting of P. massoniana, Schima superba, and Cunninghamia lanceolata. Except for Pielou evenness, the proportion of objective trees and competitive trees (with D≥15 cm) for Patrick richness and Shannon-Wiener diversity generally increased with higher diversity levels. The ranking of intraspecific, interspecific, and total CI for each index was roughly consistent with the proportion of objective trees and competitive trees, decreasing as the diversity level increased. The average intraspecific CI generally declined with higher diversity levels, while the average interspecific CI showed the opposite trend. The numerical proportion of intraspecific and interspecific CI across different diversity levels was primarily concentrated in the 5≤D<20 cm range. 2) Under different tree species diversity levels, the numerical proportion of intraspecific CI was higher than that of interspecific CI, accounting for 56.71%–81.67% of the total CI. Among interspecific CI, S. superba had the largest proportion, contributing 41.32%–78.05% to interspecific CI. 3) Across different tree species diversity levels, except for the relatively better fit of the exponential function in the medium Pielou evenness level for interspecific CI, the power function performed relatively better in fitting intraspecific, interspecific, and total CI with objective tree DBH, all showing a gradually decreasing trend as the objective tree DBH increased. Conclusion: In natural P. massoniana forests, the primary competitive pressure within the stand originates from intraspecific competition, with S. superba as the main contributor to interspecific competition pressure. The increase in tree species diversity promotes the growth and survival of large-diameter trees, alleviates the intraspecific competitive pressure on objective trees, and increases their interspecific competitive pressure. This process shifts the stand toward a more balanced trend between intraspecific and interspecific pressure. Therefore, the key to achieving sustainable forest management is to adopt management measures such as tending and thinning, and create forest stands with rich tree species and reasonable structure.

Objective: This study aims to explore the advantages of integrating data collected by handheld laser scanning (HLS) and airborne laser scanning (ALS) for individual tree parameter extraction and to assess their applicability under different forest types and understory conditions, so as to provide a scientific basis for the application of multi-source LiDAR data in precise forest surveys. Method: Three typical areas in the subtropical Fujian Province were targeted, and the HLS and ALS data were used to accurately segment individual trees in plots through a combination of automatic segmentation and visual interpretation. Individual tree parameters were extracted, and the performance of both data in estimating individual tree volume was evaluated. The influence of forest types and stand complexity on the results of individual tree parameter extraction was examined. Result: 1) The relative root mean square errors (rRMSE) for extracting diameter at breast height (DBH) and tree height from the integrated HLS and ALS data were 5.72%–5.84% and 7.36%–7.83%, respectively, and the tree-height rRMSE was reduced by 3.29%–4.19% compared with HLS alone. 2) Based on the integrated LiDAR data, Cunninghamia lanceolata was able to obtain high-precision individual tree diameter at breast height under different understory vegetation conditions, with an rRMSE of 7.05%, but Pinus massoniana was able to was able to only have good results under simple understory conditions, while broadleaf forests had high uncertainty in different understory conditions. 3) The rRMSE of single wood volume calculated based on the extracted DBH and tree height was 16.11%–17.18%. Comparing the results from HLS data alone, rRMSE of single wood volume with the integrated HLS and ALS data was reduced by 4.21%–4.30%. Conclusion: The accuracy of estimating individual tree parameters by using fused ALS and HLS data is influenced by forest types and understory conditions. The evaluation of the accuracy of individual tree parameter extraction in different scenarios provides theoretical support for optimizing future field surveys with LiDAR.

Objective: To address the challenges of remote sensing estimation caused by the sparse, short, and structurally complex characteristics of Haloxylon ammodendron in desert regions, this study explores a high accuracy method for aboveground biomass (AGB) estimation in arid desert shrublands, providing technical support for carbon stock assessment. Method: The H. ammodendron stands along the southern margin of the Gurbantunggut Desert in Xinjiang were used as the research object. Individual shrub segmentation was performed using UAV-LiDAR point cloud data, and AGB of the coverage area was estimated for expanded plots based on allometric equations. On this basis, spectral, textural, and structural features were extracted separately from UAV-MSI and UAV-LiDAR data, and random forest (RF) importance ranking was used for feature selection. Three machine learning algorithms RF, support vector machine (SVM), and extreme gradient boosting (XGBoost) were applied to develop regional-scale AGB models. Model performance was evaluated using leave-one-out cross-validation, and modeling results based on MSI features alone, LiDAR features alone, and their combination were compared. The optimal model was then used to map the spatial distribution of AGB in the H. ammodendron sites. Result: 1) Feature selection revealed that vegetation indices such as normalized difference vegetation index (NDVI), ratio vegetation index (RVI), and maximum point cloud height (Hmax) contributed significantly to AGB estimation. The combined MSI and LiDAR features exhibited a more balanced importance distribution, demonstrating strong complementarity. 2) Among all modeling methods, the AGB models based solely on UAV-MSI features outperformed those based solely on LiDAR features. RF achieved an R² of 0.82 and RMSE of 0.66 t?hm^–2, SVM achieved an R² of 0.79 and RMSE of 0.75 t?hm^–2, while XGBoost performed best with an R² of 0.84 and RMSE of 0.63 t?hm^–2, indicating that spectral features had greater predictive power. 3) The fusion of UAV-MSI and UAV-LiDAR features further improved model accuracy. The XGBoost model combining both feature sets achieved the highest accuracy, with an R² of 0.89 and RMSE of 0.53 t?hm^–2, confirming the complementary value of spectral and structural information. 4) Among the four sampling sites, Site 1 exhibited the highest average AGB at 2.50 t?hm^–2. Sites 2, 3, and 4 showed progressively lower mean AGB values (0.90, 0.84, and 0.64 t?hm^–2, respectively), with over 70% of the area having AGB values below 1 t?hm^–2. AGB spatial distribution varied significantly across sites, showing a decreasing trend with increasing distance from the oasis. Conclusion: This study has established a site-level AGB estimation workflow tailored to desert shrubs in arid regions and demonstrated the synergistic potential of combining UAV-MSI and UAV-LiDAR data in desert shrub AGB estimation. Compared to conventional field-based methods, the proposed approach offers advantages such as non-destructiveness, high resolution, and low cost, making it suitable for biomass estimation of desert shrublands in arid ecosystems.

Objective: This study aims to investigate the response patterns of water status and non-structural carbohydrates of Larix gmelinii var. principis-rupprechtii during the drought–rehydration process, clarify their relationships with drought damage severity, and identify physiological traits that can stably predict drought resistance, so as to provide a basis for the rapid evaluation and screening of drought-resistant lines of L. gmelinii var. principis-rupprechtii. Method: Three-year-old mixed-family seedlings of L. gmelinii var. principis-rupprechtii were subjected to drought stress using a pot-removal bare-root natural dehydration method. Based on needle shedding and regeneration after rehydration, drought damage severity was classified into four levels: mild, moderate, severe, and dead. Photosynthetic parameters, water potential, relative water content, and non-structural carbohydrate contents were measured. Correlation analysis and principal component analysis were conducted to determine the contributions of different traits to drought injury classification. Mildly injured seedlings were used to analyze the resilience of water-related physiological traits after rehydration and to identify effective predictive traits. Result: 1) After drought treatment, stem water potentials of mildly, moderately, severely injured, and dead seedlings were –2.43, –3.09, –3.29, and –3.55 MPa, respectively. Mildly injured seedlings showed significantly higher branch and needle relative water contents (62.75% and 73.37%, respectively) than those of the other groups. 2) After drought, there were no significant differences in non-structural carbohydrate (NSC) contents in roots and stems among different damage severity classes, and there was no significant correlation between NSC content and drought damage severity. 3) Principal component analysis indicated that water-related traits contributed more to drought damage classification than non-structural carbohydrates, with water potential showing the highest loading. After rehydration, the resilience of water-related physiological traits increased with higher post-drought water potential. Conclusion: Under short-term severe drought stress, the lethal water potential threshold of L. gmelinii var. principis-rupprechtii is –3.55 MPa, and post-drought branch water potential can be used as an effective predictor of drought injury level and the resilience of water-related physiological functions.

Objective: This study systematically investigated the growth performance, physiological characteristics, and molecular mechanisms of Populus × tomentosa ‘Qinbaiyang 3’, an elite variety, in response to water-nitrogen coupling treatments under field conditions. The purpose of this study is to address the issues of extensive water and fertilizer management and low yield per unit area in poplar plantation cultivation in northwest China, thereby providing theoretical basis and practical support for efficient poplar cultivation. Method: Two-year-old P. × tomentosa ‘Qinbaiyang 3’ seedlings with generally consistent growth vigor were used as experimental materials. A two-factor completely randomized block design was adopted, with four irrigation levels and four nitrogen application levels. Irrigation treatments: during the growing season, irrigation 3 times, with once in early June, July, and August (W3); irrigation twice, with once in early June and early July (W2); irrigation once in early June (W1); and no irrigation served as control (W0). Nitrogen treatments: fertilization three times (F3), twice (F2), once (F1) during the growing season, and no fertilization as control (F0). Furrow irrigation was applied to reach 100% field water capacity. Nitrogen fertilizer was applied in holes before irrigation (single dose: 250 g per plant). Treatments were continuously applied for two years, and growth indicators were measured at the end of the growing season. Result: Water-nitrogen coupling significantly promoted tree growth. The increment of diameter at breast height (DBH) was greatest observed under the W3F2 treatment, the tree height growth was greatest under W2F3 treatment, and the volume accumulation was also greatest under W3F2 treatment. Based on a comprehensive evaluation of growth indicators and photosynthetic performance, W3F2 was identified as the optimal treatment combination. Both irrigation and nitrogen fertilization significantly promoted secondary xylem development, and increased vessel area and fiber length, and their coupling effect was superior to that of single-factor treatments. Compared with the drought control (W0F0), the optimized water-nitrogen treatment (W3F2) significantly upregulated the expression of key genes involved in lignin and cellulose synthesis in the phloem and primary xylem, such as PaPAL2, PaCesA4, and PaCesA7A, indicating that water-nitrogen synergy promotes wood formation by enhancing cell wall anabolic metabolism. Conclusion: The W3F2 treatment (irrigation three times during the growing season and nitrogen applications twice per year) shows the most outstanding performance in promoting DBH growth and volume accumulation. This regime effectively coordinates tree growth and wood formation by enhancing photosynthetic capacity, optimizing vessel structure, and driving the expression of cell wall synthesis genes.

Objective: This study aims to clarify the short-term characteristics of sap flow and transpiration dynamics in Quercus variabilis stands under light thinning, as well as its impact on tree growth, so as to provide a theoretical basis for water management and sustainable management of Q. variabilis forests. Method: The 30-year-old Q. variabilis stands located on the southern foothills of the Taihang Mountains in northwestern Henan Province were subjected to two treatments of thinning and no thinning (control). From April to September 2023, sap flux density of trees under both treatments was continuously monitored using thermal dissipation probes. Tree-level biological factors (such as diameter at breast height, sapwood area, and stand density) and meteorological variables [including air temperature, relative humidity, solar radiation, and vapor pressure deficit (VPD)] were simultaneously recorded. With the above measurements, the effects of thinning on individual tree sap flux density and stand-scale transpiration were evaluated, and their relationships with environmental drivers were analyzed. Result: 1) The diurnal course of sap flux density in Q. variabilis exhibited a unimodal pattern. Except in July, thinning did not significantly alter the onset time or peak timing of the diurnal sap flux density dynamics. Sap flux density in thinned trees was consistently higher than that in unthinned trees throughout the growing season, and this difference first increased and then decreased with seasonal progression, indicating that the thinning effect was seasonally dependent. 2) After thinning, the explanatory power of radiation (R²=0.52) and VPD (R²=0.42) for sap flux density variation increased, indicating an increased sensitivity of sap flow to abiotic environmental drivers. The explanatory power of radiation on changes in for sap flux density was higher than that of VPD, suggesting that sap flux density in this region may be more strongly influenced by light-related processes rather than primarily constrained by atmospheric dryness. 3) There was no significant correlation between sap flux density and tree diameter (P>0.05), indicating that individual tree size was not the primary driver of sap flow variation under the current stand structure and soil moisture conditions. 4) Although the total sapwood area of the thinned stand was approximately 27% lower than that of the control, the seasonal total transpiration was still about 9% higher than that of the control, which may be associated with the increased sap flux density at the individual tree level. Conclusion: Under the light thinning intensity condition applied in this study, Q. variabilis stands exhibit enhanced sap flow and transpiration responses in the short term, indicating a potential regulatory effect on stand water use processes. These findings provide a scientific basis for the coordinated optimization of water regulation and structural adjustment in Q. variabilis and other deciduous broadleaf forests.

Objective: This study aims to investigate the freshness retention and changes in total wax content and wax composition during low-temperature storage of post-harvest Lycium barbarum, and analyze the influence of fruit peel wax on berry preservation, so as to provide scientific basis for extending the quality retention period of fresh L. barbarum. Method: The primary cultivated varieties ‘Ningqi No. 5’ and ‘Ningqi No. 7’ from Ningxia were used as test materials. The fruits were stored at 4 ℃ and 13 ℃, and the relevant indicators periodically measured using plant physiology techniques and GC-MS analysis. Result: 1) During the 20-day storage period, the weight loss rate, corruption rate, and colour ?E values of the fruits stored at 4 ℃ were significantly lower than those stored at 13 ℃ (P<0.05). The storage at 4 ℃ effectively maintained hundred-grain weight and respiration rate, reduced declines in ascorbic acid, soluble solids, and titratable acid content, and maintained polysaccharide, flavonoid, and betaine levels. 2) GC-MS analysis revealed that 4 ℃ treatment significantly inhibited the reduction in cuticle wax content of Ningqi No. 5 and Ningqi No. 7 fruit peel (P<0.05), with wax levels significantly higher than those at 13 ℃ (P<0.05). 3) The correlation analysis showed that there was highly significant negative correlation between wax content and weight loss rate for all treatments (P<0.01), and there was also a significant negative correlation between wax content and corruption rate (P<0.05). Furthermore, wax content exhibited significant correlations with other indicators closely related to preservation efficacy: a highly significant negative correlation with colour difference ?E (P<0.01), and significant positive correlations with hundred-grain weight, respiration rate, soluble solids, ascorbic acid, flavonoids, polysaccharides, and betaine (P<0.05). The results indicate that wax content plays a crucial role in maintaining post-harvest fruit preservation. Conclusion: In summary, the appropriate storage temperature (4 ℃) significantly influences the maintenance of post-harvest wax content and freshness retention in L. barbarum. Ningqi No. 5 has superior low-temperature storage performance compared to Ningqi No. 7. These findings provide theoretical foundations and practical guidance for the post-harvest storage and preservation of L. barbarum.

Objective: This study aims to combine the fast-growing traits of Populus ‘Nanlin 895’ with the high insect resistance of Bt-transgenic Populus nigra through hybridization, to analyze the effects of the Bt gene and sex on early growth, and to comprehensively evaluate the growth traits of the hybrid progeny for superior individual selection. Method: The ‘Nanlin 895’ poplar was used as the female parent and two Bt-transgenic Populus × euramericana clones (‘B3-44’ and ‘G-252’) were used as male parents, and two full-sib families were obtained through hybridization. Through seedling cultivation, the final effective sample size of 5 246 F₁ hybrid progeny were generated. During the dormancy period, plant height (PH), ground diameter (GD), and first-order branch number (FBN) were uniformly measured. PCR was employed for molecular identification of the Bt gene and progeny gender. The average membership function method and the Breckin multi-trait comprehensive evaluation method were used to comprehensively evaluate the growth traits. Result: 1) The three growth traits of the hybrid progeny exhibited abundant phenotypic variation, with coefficients of variation ranging from 20.3% to 48.3%. The FBN showed the highest level of variation. 2) The positive rate for the Bt gene was 35.3%. At seedling stage, the PH (270.66 cm) of Bt-positive progeny was significantly lower than that (274.23 cm) of Bt-negative progeny, but there were no significant differences in GD or FBN between Bt-positive progeny and Bt-negative progeny. 3) The gender ratio of the progeny was significantly skewed towards males, yet there were no significant differences in seedling growth traits between female and male progeny. 4) The top 100 superior individuals selected by the two comprehensive evaluation methods showed a high degree of overlap (96 individuals). Their mean PH and GD (351.58 cm, 45.48 mm) were significantly increased by 28.8% and 43.1%, respectively, compared to the population mean, and their FBN was more stable. Conclusion: The Bt gene has been successfully introduced into the poplar genome via hybridization, which may exert an inhibitory effect on seedling height growth to a certain extent. The gender of the progeny has no significant effect on early growth. Both the membership function and Breckin methods demonstrate good consistency and reliability for early selection in juvenile poplar. The superior individuals selected in this study provide a solid material foundation for breeding new catkin-free, fast-growing, and highly insect-resistant poplar varieties.

Objective: This study aims to generate tetraploid olive plants, analyze their phenotypic differences from wild-type diploids, and explore the genetic regulatory mechanism underlying the cell enlargement phenotype in the tetraploids. Method: Tetraploid induction was performed using a colchicine and oryzalin mixture via a droplet application. Ploidy was rapidly identified by flow cytometry. Karyotype analysis was performed using improved phenol fuchsin staining. Leaf cross-sections of tetraploid plants were made using vibratome sectioning, and observed after toluidine blue staining. Leaf epidermal cells of tetraploids were examined by PI staining. Gene expression profiling and differentially expressed genes (DEGs) enrichment analysis of leaves of different ploidy plants were conducted using the Illumina platform. Based on the T2T high-quality olive genome, EXP gene family members were identified and characterized using Blastp, HMM, ProtParam, Cello version 2.5, MEGA11, AlphaFold3.0, SAVES, and PyMOL, and their expression patterns were further elucidated. Result: A total of 23 tetraploid olive plants were obtained, with an induction efficiency of 24.46%. Compared to diploids, tetraploids exhibited a cell enlargement phenotype, with significantly enlarged epidermal cells and stomata (P<0.000 1). RNA-seq identified 4 743 DEGs (2 371 up-regulated and 2 372 down-regulated). Through differential gene expression analysis, the auxin signaling pathway closely associated with cell enlargement was significantly enriched. Two markedly upregulated EXP members were identified and further validated by qRT-PCR. A comprehensive genome-wide analysis of the EXP gene family was completed. Conclusion: The EXP gene family is closely associated with tetraploid cell enlargement, laying a foundation for further exploration of the gigas phenotype in polyploids in the future.

Objective: Drought stress caused by global climate change has become a key bottleneck restricting forest productivity and ecological adaptability. Hybrid breeding is an important strategy for integrating superior traits from both parents and enhancing drought resistance in trees. This study aims to analyze the differences in key photosynthetic and water-use traits under drought stress between Populus simonii × P. nigra hybrid progenies and their parents, clarify the role of these traits in the formation and maintenance of heterosis for drought-resistant growth, so as to provide a theoretical basis for drought-resistance genetic improvement in poplar. Method: P. simonii × P. nigra hybrid progenies (high-growth potential H1, H2, H3 and low-growth potential L1, L2, L3) and their parents were subjected to well-watered and drought-stress treatments. Growth, photosynthetic parameters (leaf area, chlorophyll content, net photosynthetic rate P_n, maximum photochemical efficiency of PSⅡ F_v/F_m), and water-use indicators (instantaneous water use efficiency WUE_i, long-term water use efficiency WUE_L, leaf water retention) were measured. Heterosis analysis and correlation statistics were used to systematically compare the differences in photosynthetic and water-use characteristics and their effects on drought-resistant growth. Result: Under drought stress, the net growth in height and ground diameter of high-growth potential progenies stably showed positive mid-parent heterosis (MPH 4.39%?47.26%), and most key photosynthetic and water-use traits also showed significant mid-parent or high-parent heterosis (MPH 0.24%?44.94%). In contrast, the growth traits of low-growth potential progenies were generally below the mid-parent value, with no significant or negative heterosis in photosynthetic and water-use traits. Correlation analysis showed that total leaf area, chlorophyll content, P_n, and F_v/F_m were significantly positively correlated with growth (P < 0.01). Total leaf area, chlorophyll content, P_n, and δ¹³C value could serve as key indicators for early selection of drought-resistant and fast-growing progenies. Conclusion: The growth heterosis of P. simonii × P. nigra hybrid progenies remains stable under drought stress and is closely related to the synergistic improvement of photosynthetic efficiency and water use efficiency. High-growth potential progenies (especially H1 and H3) form outstanding drought-resistant growth advantages by integrating the high photosynthetic capacity and efficient water-use strategies of both parents. This study provides a basis for trait selection and a physiological mechanism explanation for breeding drought-resistant and fast-growing poplar varieties.

Objective: To protect and develop the Camellia phellocapsa, a systematic survey of C. phellocapsa was conducted, followed by grafting and preservation. The unique germplasm resources with high oil yield and ornamental value were explored. This study aims to provide crucial resources for the development and utilization of C. phellocapsa and the breeding of new varieties. Method: A systematic survey and evaluation were conducted on 268 mature C. phellocapsa in Chaling County, focusing on morphological characteristics, flowering period, fruit economic traits, dry seed oil content, and fatty acid composition. Through comparing the data collected in two consecutive years, the principal component analysis and membership function analysis were used to comprehensively evaluate the most outstanding individual trees. Twelve high-yielding, distinct new germplasm lines were preliminarily identified primarily based on fruit yield per tree, fruit morphological distinctiveness, flower quantity, and color, and designated as follows: A-88, A-102, D-21, D-22, D-47, F-2, A-52, A-109, A-127, D-13, D-36, and D-50. Result: In terms of individual fruit weight and fruit yield per plant, A-88 performed exceptionally well, with an average individual fruit weight of 131.57 g, which was 115.58% higher than that of A-127, a statistically significant difference (P<0.05). D-47 had the highest fruit yield per plant, producing 65 fruits per plant with a total weight of 8.85 kg. In terms of fruit morphology, A-52 had the largest fruit diameter (89.93 mm), which was 65.43% greater than that of D-50. A-102 exhibited the best fruit length (96 mm), which was 71.18% greater than the shortest fruit length of A-109. Comparison revealed that although A-52 had the largest fruit diameter, its individual fruit weight was significantly lower than that of A-88 (P<0.05), indicating that factors such as fruit shape and skin thickness also influence individual fruit weight. Regarding oil characteristics, A-88 had the highest oil content in dry seeds and unsaturated fatty acid content, at 42.13% and 86.43%, respectively, and the oil content in dry seeds was 20.54% higher than that of D-47, a significant difference (P<0.05), and its unsaturated fatty acid content was 3.22% higher than that of A-127, which had the lowest value. F-2 had the highest oleic acid content at 82.14%, which was 12.66% higher than the lowest value in A-127, and the difference was significant (P<0.05). In summary, A-88 has both high oil content and high unsaturated fatty acids, while F-2 stands out for its high oleic acid content. Both exhibit significant potential for development in edible and cosmetic oils. Regarding floral phenotypes, F-2 exhibited outstanding ornamental traits. Its flowers displayed a vivid rose red color (RHS 58A), with a maximum of 402 blooms per plant and a prolonged peak flowering period of 42 days, demonstrating outstanding ornamental qualities. D-21 and D-47 exhibited peach-pink flowers (RHS N57A) with abundant blooms, also possessing considerable ornamental value. Comprehensively, F-2 exhibits outstanding traits in flower color, flower quantity, flowering period, and flower size, demonstrating high potential for both ornamental use and breeding. Correlation analysis revealed that there were 4 pairs of traits with extremely significant correlations and 8 pairs with significant correlations among 28 traits. Principal component analysis indicated that the cumulative contribution rate of the first 4 principal components reached 82.75%. Through the membership function method, a comprehensive evaluation was conducted on 12 germplasm samples, and ultimately six C. phellocapsa with outstanding phenotypic traits were successfully selected. Conclusion: The results indicate that six C. phellocapsa germplasm with excellent phenotypic traits have been screened, namely A-88, A-102, D-22, D-21, D-47, F-2, providing important reference for the evaluation of C. phellocapsa germplasm resources and the selection of superior varieties.

Objective: This study aims to address the issue of stray dogs (Canis lupus familiaris) invasion into Beijing Songshan National Nature Reserve, which initially arose from village relocation in the Yanqing Zone of the 2022 Beijing Winter Olympic Games, through examining the disturbance imposed by such dogs on six dominant wild mammal species within the reserve. Method: Based on camera trap monitoring data from 2021 to 2023, this study employed spatiotemporal niche modeling and nonparametric kernel density estimation to examine whether stray dog activity influences wildlife occurrence within the reserve. Result: The population of stray dogs exhibited a phased pattern of spatial expansion. During venue construction and the Games period, dogs were largely restricted to the competition zone and its immediate surroundings. After the event, they continued to disperse deeper into the core area of the nature reserve. Furthermore, the stray dogs exhibited a highly consistent bimodal daily activity pattern, with peak activity occurring from 09:00 to 12:00 and from 20:00 to 02:00 the next day. In the activity area of stray dogs, the activity pattern of roe deer (Capreolus pygargus) shifted from unimodal peak (08:00—12:00) to a bimodal pattern, with peaks occurring at 06:00—10:00 and 17:00—19:00. The activity pattern of Chinese goral (Naemorhedus griseus) shifted from a unimodal peak (18:00—22:00) to a bimodal pattern in 2022 (05:00—09:00 and 17:00—19:00), with its activity peaks narrowing markedly in 2023 (05:00—07:00 and 14:00—17:00). Wild boar (Sus scrofa) exhibited a marked preference for afternoon activity (14:00—20:00). Raccoon dog (Nyctereutes procyonoides) shifted their peak activity from 23:00—02:00(the following day) in 2021 to a wider interval of 20:00—03:00(the following day) in 2022. However, by 2023, the detection rate of raccoon dogs declined sharply, and no distinct activity rhythm could be distinguished. The common pheasant (Phasianus colchicus) exhibited a shift in its activity peaks from 06:00—10:00 and 14:00—17:00 in 2021 to 05:00—09:00 and 13:00—16:00 in 2022. This bimodal pattern further differentiated in 2023, extending to 06:00—10:00 and 14:00—19:00. Conversely, the activity peak of the Koklass pheasant (Pucrasia macrolopha), initially concentrated between 15:00—19:00 in 2021, had completely shifted to the 06:00—11:00 in 2023. Conclusion: Wildlife activity in Songshan National Nature Reserve shows a distinct temporal cumulative effect in response to the disturbance of stray dogs. As the activity range of stray dogs expands, the living space of wildlife is continuously compressed, and the original activity rhythms of wildlife have been forced to adjust. To alleviate the persistent and progressive pressure exerted by stray dogs on native wildlife within the reserve, the formulation and implementation of scientific and humane management strategies have become an urgent priority for the reserve authority.

Objective: The purpose of this study is to prepare natural wood into a Janus wood-based functional material with an asymmetric structure via chemical modification methods, so as to endow it with excellent hydrovoltaic power generation performance, thereby reducing the dependence of hydrovoltaic technology on non-degradable or expensive nanomaterials, and providing new design ideas for the development of high-performance and long-life wood-based hydrovoltaic generators. Method: Natural balsa wood was selected as the substrate and cut along the direction perpendicular to the growth of trees to retain its natural micro-channels and expose the intrinsic anisotropic structure. Firstly, the negatively charged carboxyl groups were selectively introduced on the surface of wood fiber by TEMPO oxidation reaction. Further functionalization was performed by citric acid esterification reaction to construct different charge densities within the material. Subsequently, two kinds of wood with different degrees of modification were assembled to successfully prepare a water volt generator with Janus structure with significant differences in charge density, stable microstructure, and green simplified preparation process. Result: The microstructure analysis showed that highly ordered and aligned ion nanochannels were formed inside the modified wood, and the inner wall of the channel was rich in functional groups such as dissociative carboxyl groups, which provided an ideal path for the selective and rapid transport of ions. The open circuit voltage of the water volt generator based on the Janus wood-based material was able to reach up to 184 mV, which is about 3.5 times that of the natural wood (the output voltage is only 53 mV). At the same time, its output power density was increased to 0.29 nW·cm^?2. With seven water volt power generation units integrated in series, the cumulative output voltage was able to reach as high as 1.44 V, which can successfully drive a small calculator to work stably, which preliminarily proves its practical potential in power supply for micro-electronic devices. Conclusion: This work has successfully transformed natural wood into high-performance hydrovoltaic power generation materials through a novel strategy of two-step continuous chemical modification to construct a Janus gradient structure. This study not only provides a new material design idea for the development of low-cost, biodegradable green energy conversion devices, but also shows the great application prospects of wood-based functional materials in the field of sustainable energy.

Objective: This study aims to investigate the mechanical characteristics of Camellia oleifera (oil tea) seedlings to address issues such as excessive clamping force leading to seedling damage and excessive cutting force causing scion seedlings to slip during the mechanized grafting process, providing references for the design and optimization of automated grafting equipment for oil tea. Method: The “Changlin Series No. 53” oil tea seedlings were used as the research object, the main physical characteristics of rootstock seedlings were obtained by measuring physical parameters and performing statistical data analysis. Based on grafting technology standards, two types of seedlings (rootstock and scion) were divided into three groups for radial compression test and three-point bending test. Shear tests on both rootstock and scion seedlings were performed using the Box-Behnken experimental design method, and the influence of tool edge angle, loading speed, and seedling diameter on shear strength was analyzed using response surface methodology. Result: The diameter range of rootstock seedlings was 2.72–4.48 mm, with an average diameter of 3.16 mm, an average mass of 2.34 g, and an average moisture content of 80.12%. The diameter range of scion seedlings was 2.03–3.50 mm, with an average diameter of 2.75 mm, an average mass of 1.84 g, and an average moisture content of 81.34%. The average peak compressive force and maximum compression of rootstock seedlings were 139.4 N and 0.78 mm, respectively. For scion seedlings, these values were 198.1 N and 0.70 mm. The average peak bending force, bending elasticity modulus, and bending strength of rootstock seedlings were 8.24 N, 29.007 MPa, and 8.168 MPa, respectively. The average peak bending force, bending elasticity modulus, and bending strength of scion seedlings were 8.20 N, 23.346 MPa, and 18.497 MPa, respectively. The average shear strength of rootstock and scion seedlings was 1.445 MPa and 3.025 MPa, respectively, with their maximum shear forces of 24.65 N and 24.83 N. Seedling diameter and tool edge angle significantly affected shear strength, while loading speed had no significant impact. Conclusion: The results of the radial compression test indicate that the peak compressive force, maximum compression, and compressive strength of both rootstock and scion seedlings increase with the diameter, with the compressive strength of scion seedlings being higher than that of rootstock seedlings. The results of the three-point bending test show that the peak bending force of both rootstock and scion seedlings increases with diameter, but the bending strength of rootstock samples is generally lower than that of scion samples, and the brittleness of rootstock samples is greater than that of scion samples. The shear test results indicate that the shear strength of rootstock decreases as the tool edge angle decreases, while it increases with the diameter of the rootstock. The shear strength of scion seedlings gradually decreases as the tool edge angle decreases, and shows a trend of first slight decrease followed by rapid increase with increasing scion diameter. The shear strength of both types of seedlings initially decreases and then increases as the loading speed increases. Additionally, the clamping force applied to scion seedlings should range between 100 and 150 N, while the clamping force on rootstock seedlings should not exceed 90 N.

Forest carbon storage plays a crucial role in regulating the global carbon cycle and mitigating climate change. Accurate estimation and dynamic monitoring of forest carbon stocks constitute a fundamental basis for advancing the understanding of terrestrial ecosystem carbon cycling processes and for achieving national carbon neutrality and carbon peaking goals. In recent years, development in remote sensing technology has substantially enhanced the capability for large-scale estimation of forest carbon storage. However, accurate carbon stock estimation in northeast China still faces challenging due to the region’s high spatial heterogeneities in forest structure, species composition, origin, and age. This study systematically reviews research progress in forest carbon monitoring in northeast China based on 233 Chinese and English literature, and integrates key institutional milestones in global climate governance, including the establishment of the REDD+ mechanism and the implementation guidelines of the Paris Agreement, together with major technological advances such as the emergence of spaceborne LiDAR-enabled global forest structural observations and the widespread adoption of cloud-computing platforms. The development process is divided into three stages: coarse-resolution empirical estimation (pre-2010), medium-resolution mechanistic modeling (2011—2018), and high-resolution intelligent estimation (since 2019). Based on the characteristics of data sources, modeling approaches, and major achievements at each stage, a comprehensive analysis was conducted on the key challenges in current research and future development directions. Literature analysis indicated that forest carbon stock monitoring in northeast China has evolved from sole reliance on coarse resolution optical remote sensing data to the deep integration of high-resolution multimodal, multi-temporal, and multi-scale remote sensing datasets. Concurrently, estimation methods have transitioned from empirical statistical models to process-based models and, more recently, to data-driven deep learning approaches. These advances have significantly improved the accuracy and spatiotemporal representativeness of forest carbon stock estimates, providing essential scientific evidence and technical support for assessing forest carbon sink capacity, strengthening the shields for ecological security, and promoting high-quality forestry development in northeast China.