Objective: This study aims to elucidate the origin, succession, and dispersal processes of the genus Cunninghamia, analyze the genetic diversity and genetic structure characteristics of modern Chinese fir (Cunninghamia lanceolata), and reveal the formation mechanisms of its contemporary distribution pattern. Method: Literature on Cunninghamia macrofossils, pollen fossils, and subfossil wood was reviewed to summarize the relationship between the genus’s origin, succession, dispersal during geological history and its modern distribution. Materials included: a national Chinese fir provenance trial forest established in 1981 in Dagangshan, Jiangxi Province (183 provenances, 1440 individual trees); a provenance trial forest in Shaowu, Fujian Province (14 individuals of Taiwan Chinese fir); and 20 individuals of Dechang Chinese fir from Dechang, Sichuan Province. Provenances were grouped into 10 provenance-region populations, 13 provincial populations, and 23 geographical provenance populations for genetic diversity and structure analysis. SSR sequencing was performed on 1352 individuals from 174 provenances. Chloroplast DNA (cpDNA) sequencing was performed on 531 individuals from 177 provenances, 4 individuals of Taiwan Chinese fir, and 6 individuals of Dechang Chinese fir. Result: Genetic variation within different geographical provenance populations of Chinese fir accounted for 98.20%–99.16% of the total variations, and only 0.84%–1.80% of the variations originated from among different geographical provenance populations. This indicates that the genetic composition and structure among different geographical provenance populations of Chinese fir have tended to be consistent, and there are no significant differences in the genetic structure among different geographical provenance populations. Chinese fir belongs to one genus and one species. Taiwanese Chinese fir may have been introduced from Zhejiang or Fujian. Due to long-term adaptation to local environmental conditions, the Dechang population has developed a relatively independent genetic structure, likely a result of localized cultivation and isolation from external gene flow. The low level of genetic differentiation among geographical provenances could be attributed to the relatively high level of gene flow (N_m = 2.689–6.328) among populations. However, this gene flow was not the result of natural processes, but rather the outcome of extensive and long-distance introductions and plantations over the past 2 000 years. Between 1000 and 1600 AD, reforestation was carried out by planting Chinese fir and other economic trees in the southern regions of China, which was called the great afforestation in southern China and marked the “first forest revolution” in Chinese history. The rapid development of Chinese fir plantations was the result of tax reforms in response to the “timber crisis in the Song dynasty”, successfully meeting the large demand for timber during the Song, Yuan and Ming dynasties and exerting an influence to this day. Chinese fir remains the largest afforestation tree species in terms of area and volume in China, with its largest area reaching 13.8 million hectares (1999—2003). Conclusion: During the last glacial maximum of the Quaternary period, Chinese fir was retreated to southern refugia, nearing extinction. Modern Chinese fir may be originated from the last relict population or individual plants formed by chloroplast haplotype H14. The lack of significant genetic structure differences among geographical provenance populations suggests that the 177 provenances originating before 1955 are essentially all derived from plantations. Two millennia of cultivation, particularly the extensive planting of Chinese fir in south China since the Song dynasty (which created the “first forest revolution” in China’s history), combined with long-distance introductions, cultivation, and a well-developed timber trade, has led to the near-complete disappearance of natural Chinese fir forests that have entirely converted into plantations, becoming a miracle in the history of world forestry. As a landmark tree species of this forest revolution, it implies that the establishment of the forestry system and the budding of afforestation theory and technology can be traced back to before the Song dynasty in China.

Objective: This study aims to clarify the dynamics of carbon pool changes and carbon balance responses of plantations under harvesting disturbances, so as to provide guidance for scientific management of the dual enhancement of timber production and carbon sink functions of plantations. Method: Pinus massoniana plantations in subtropical China were taken as the object. The CBM-CFS3 model improved by parameter localization was used to simulate differences in carbon pool components and future carbon sink dynamics over the next 41 years under four harvesting intensities (0%, 10%, 25% and 40%). Result: The Richards equation provided a good fit for various types of P. massoniana plantations (R²≥0.57, MAE≤15.54 m³?hm^?2, RMSE≤17.50 m³?hm^?2), and was able to effectively characterize stand growth patterns of P. massoniana across the region. In 2018, the average ecosystem carbon density was 122.97 Mg?hm^?2, with contributions from vegetation layer (34.79 Mg?hm^?2), dead organic matter (32.00 Mg?hm^?2), and soil (56.18 Mg?hm^?2). Within the vegetation carbon pool, the order of carbon density was stem > root > branch > foliage. Under management scenarios with a harvesting cycle of 15-year, the maximum carbon density and the maximum sequestration rate achieved by P. massoniana plantations between 2019 and 2060 were as the follow: 10% harvesting intensity > no harvesting > 25% harvesting intensity > 40% harvesting intensity. Specifically, under the 15-year harvesting cycle with 10% harvesting intensity scenario, the maximum carbon density reached 194.73 Mg?hm^?2, and a maximum sequestration rate reached 2.30 Mg?hm^?2a^?1. By 2060, the total carbon stock of P. massoniana plantations in China could reach 494.17 Tg, including 217.94 Tg in biomass. Conclusion: The CBM-CFS3 model improved by parameter localization can effectively simulate distributions of carbon pools and dynamics of carbon density in P. massoniana plantations. Under the scenario of 10% harvesting intensity, P. massoniana plantations have the greatest carbon sequestration potential, balancing timber production with carbon sink function. It is recommended to adopt moderate harvesting intensity and cycle in plantation management to promote the rapid renewal of aging stands, thereby ensuring high timber yield while enhancing carbon sequestration capacity.

Objective: In this study, the Pinus tabuliformis-Quercus wutaishanica mixed forest in the Huanglong Mountain region of Shaanxi Province was taken as the research object, with pure stands of P. tabuliformis and Q. wutaishanica serving as controls. This study analyzed the variation characteristics of soil microbial source carbon (living biomass carbon and necromass carbon) under different stand types, and investigated the impact of P. tabuliformis-Q. wutaishanica mixed forests compared to the pure forests on soil microbial source carbon accumulation, aiming to elucidate the key microbial functional mechanisms driving these changes, and to identify the environmental factors regulating this process. Method: The phospholipid fatty acid (PLFA) method was used to determine microbial live biomass carbon content, and the amino sugar method was used to determine microbial necromass carbon content. Microbial metagenomic sequencing was employed, annotating against the Carbohydrate-Active Enzymes (CAZyme) database and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, to obtain and analyze the characteristics of microbial carbon-decomposition functional genes. Mantel test was conducted to explore the interactive relationships among carbon-decomposition functional genes, soil nutrients, and microbial derived carbon. Based on the distributional characteristics of the data, both parametric and nonparametric tests were applied to assess significant differences among groups and perform multiple comparisons. All statistical analyses and data visualizations were performed using R v4.2.1. Result: 1) Compared with pure P. tabuliformis and pure Q. wutaishanica stands, the mixed forests significantly increased the microbial PLFA biomass carbon content of bacteria (Gram-positive bacteria: 37.5%–54.9%), fungi (ascomycota and basidiomycota: 35.7%–42.5%; arbuscular mycorrhizal fungi: 23.7%–95.8%; zygomycota: 57.8%–89.9%), and total microorganisms (37.7%–55.1%). 2) The mixed forests significantly enhanced the content of bacterial necromass carbon (45.0%–56.7%) and total microbial necromass carbon (20.2%–28.4%), and increased the contributions of bacterial necromass carbon (44.3%–59.9%), fungal necromass carbon (15.3%–30.6%), and total microbial necromass carbon (19.3%–34.7%) to the soil organic carbon pool. 3) The relative abundance of CAZyme genes involved in the decomposition of plant-derived carbon (hemicellulose, cellulose, and lignin) and bacterial-derived carbon (peptidoglycan) in the P. tabuliformis-Q. wutaishanica mixed forests were intermediate between those in pure P. tabuliformis and pure Q. wutaishanica forests, while the relative abundance of chitin-degrading CAZyme genes was higher than in pure forests. KEGG functional genes related to carbon degradation exhibited a similar trend. 4) Bacterial necromas carbon content showed significant positive correlations with the PLFA biomass carbon content of actinobacteria (R = 0.65, P< 0.01), firmicutes (R = 0.60, P< 0.01), and Gram-negative bacteria (R = 0.67, P< 0.01). Fungal necromass carbon content was significantly positively correlated with the PLFA biomass carbon content of ascomycota and basidiomycota (R = 0.53, P< 0.05), arbuscular mycorrhizal fungi (R = 0.63, P< 0.05), and zygomycota (R = 0.74, P< 0.01). Both microbial PLFA biomass carbon and necromass carbon contents were significantly influenced by soil available phosphorus (AP) content. The fungal-to-bacterial PLFA biomass carbon ratio and the fungal-to-bacterial necromass carbon ratio were both significantly positively correlated (P< 0.01) with the relative abundance of CAZyme genes decomposing plant-derived carbon and bacterial-derived carbon, respectively. Conclusion: The mixture of P. tabuliformis and Q. wutaishanica can significantly increase the contents of bacterial, fungal, and microbial PLFA biomass carbon and necromass carbon, and also enhance the contribution of bacterial, fungal, and microbial necromass carbon to the soil organic carbon pool. In the mixed forests, the relative abundance of CAZyme genes and the absolute abundance of carbon-degrading functional genes are intermediate between those in pure P. tabuliformis and pure Q. wutaishanica forests. Both the fungal-to-bacterial PLFA biomass carbon ratio and the fungal-to-bacterial necromass carbon ratio are influenced by the relative abundance of CAZyme genes and the absolute abundance of carbon-degrading functional genes. Soil phosphorus availability is identified as a key factor regulating the accumulation of microbial PLFA biomass and necromass carbon.

Objective: By monitoring the nutrient content, stoichiometric characteristics and nutrient reabsorption of various organs of Populus tomentosa at different stages after tending thinning, this study aims to illustrate the response of trees to light, water and nutrient resources at the organ scale under different thinning intensities, and provide theoretical support for the cultivation and management of P. tomentosa plantations in the North China Plain. Method: The 8-year-old triploid P. tomentosa S86 plantation in the North China Plain was taken as the research object, and three thinning intensities were set: no thinning (NT), alternate row thinning (50% thinning, T50), and alternate row and alternate plant thinning (75% thinning, T75). By sampling the leaves, branches, trunks and roots of forest trees, the nutrient content and stoichiometric ratio of various organs, as well as leaf reabsorption efficiency and relative reabsorption rate of P. tomentosa during the growing season in August and November were analyzed, to explore the coupling relationships between nutrient content, stoichiometry and reabsorption at different stages. Result: 1) From a comprehensive perspective of the two periods, thinning intensity only had a significant impact on leaf phosphorus content and trunk carbon content. In November, thinning significantly increased the accumulation of potassium in leaves, and T50 and T75 respectively increased by 33.43% and 35.74% compared with NT. 2) C/N, C/P, and C/K represent the ability to absorb nitrogen, phosphorus, and potassium nutrients under carbon stabilization, and can be used as indicators to judge plant nutrient absorption rate and utilization efficiency. There were significant differences in leaf C/N, C/P, C/K, and N/P between August and November. In addition, compared with branches, trunks and roots, the stoichiometric characteristics of leaves were more susceptible to the influence of period, thinning and their interactions. Among them, the intensity of thinning had a significant impact on the C/P and N/P of P. tomentosa leaves. 3) The nitrogen reabsorption efficiency (NRE) of P. tomentosa leaves under different thinning intensities was 14.64%–24.55%, the phosphorus reabsorption efficiency (PRE) was 18.87%–34.97%, and the potassium reabsorption efficiency (KRE) was 7.00%–33.59%. As the thinning intensity increased, the potassium return efficiency of leaves decreased. Thinning by 50% and 75% significantly reduced the potassium reabsorption efficiency of forest trees by 53.56% and 79.16%, respectively. 4) There was a significant correlation between nutrient content and nutrient reabsorption efficiency, and the correlation was positive for mature leaves in August, and negative for litter leaves in November. The contribution rates of potassium content in mature leaves, N/K ratio in senescent leaves, and phosphorus content in senescent leaves to nutrient resorption ranked the top three, at 35.2%, 27.0%, and 19.9% respectively. Conclusion: Nutrient stoichiometric characteristics of each organ and the reabsorption of nitrogen and phosphorus in leaves are insensitive to the short-term response of thinning. However, the nutrient absorption and utilization strategies of various organs of the poplar at different periods during the growing season are different. Based on the “N/P threshold hypothesis”, the N/P range is 10.05–11.06 under different thinning intensities, indicating that the growth of P. tomentosa in this area is limited by nitrogen, and it is recommended to apply more nitrogen fertilizer in stand management after thinning. At the same time, the results show that NRE/PRE<1. Based on the “relative reabsorption hypothesis”, addition of an appropriate amount of phosphorus fertilizer to the nitrogen fertilizer can promote the physiological metabolism of forest trees and improve the growth potential of forest trees.

Objective: This study targets eight dominant understory species in a subtropical moso bamboo forest, and investigates their leaf functional traits in response to simulated nitrogen deposition, aiming to elucidate the ecological adaptation strategies of understory plants to nitrogen deposition, and provide a scientific basis for nitrogen deposition management in regional moso bamboo forest ecosystems. Method: Two simulated nitrogen deposition modes was set up, one above the canopy and the other below the canopy with organic (a urea-glycine mixture) and inorganic (ammonium nitrate). There were a total of six treatment groups: canopy inorganic nitrogen addition (CIN), canopy organic nitrogen addition (CON), canopy control (CCK), understory inorganic nitrogen addition (UIN), understory organic nitrogen addition (UON), and understory control (UCK). The nitrogen addition amount for each treatment group was uniformly at a rate of 50 kg·hm^?2a^?1, while control plots received an equivalent volume of water. After three years, eight leaf functional traits (specific leaf area, leaf dry matter content, leaf thickness, plant height, and contents of total nitrogen, phosphorus, potassium, and N∶P ratio) were determined for four shrub species (Rubus buergeri, Rubus corchorifolius, Ardisia japonica, Wisteria sinensis) and four herbaceous species (Chelonopsis chekiangensis, Lophatherum gracile, Parathelypteris glanduligera, Carex spp.). Result: 1) Except for leaf dry matter content, leaf functional traits did not significantly respond to the simulated nitrogen deposition (above/below canopy) or nitrogen form (organic/inorganic). However, there were significant interspecific differences, particularly between herbs and shrubs, and between Fabaceae and non-Fabaceae shrubs. 2) Simulated nitrogen deposition significantly increased leaf nitrogen content in both herbs and shrubs. Herbs exhibited increased leaf potassium content and nitrogen-to-phosphorus ratio, but decreased leaf dry matter content. Shrub height significantly increased. Fabaceae shrubs showed increased plant height but decreased specific leaf area, while non-Fabaceae shrubs displayed increased leaf nitrogen content and nitrogen-to-phosphorus ratio. 3) Leaf dry matter content was negatively correlated with nitrogen content across all treatments. Leaf nitrogen content was positively correlated with phosphorus content only under CCK, CIN, and UCK treatments. Nitrogen-to-phosphorus ratio was positively correlated with nitrogen content only in CCK, CON, and UIN treatments. Specific leaf area was negatively correlated with leaf thickness solely under CON treatment, and leaf thickness was positively correlated with plant height under CCK and CIN treatments. Conclusion: This study has revealed differences in adaptation strategies to nitrogen deposition between herbaceous plants and shrubs, and between Fabaceae and non-Fabaceae shrubs in a moso bamboo forest. In response to nitrogen deposition, herbaceous plants not only enhance their resource-acquisition strategy through increasing leaf nitrogen content but also attenuate their resource-conservation strategy by reducing leaf dry matter content. Non-Fabaceae shrubs only increase resource-acquisition functional traits such as leaf nitrogen content, without adjusting resource-conservation traits. In contrast, Fabaceae shrubs adapt to nitrogen-enriched environments by maintaining leaf nitrogen-phosphorus stoichiometric balance.

Objective: The decomposition-reconstruction method is integrated with machine learning model to simulate the net carbon exchange capacity of plantation ecosystems, aiming to provide an effective tool for high-precision simulation and prediction of the carbon sequestration capacity of artificial forest ecosystems in the “Three North” region. Method: Based on the daily observation dataset from the poplar plantation flux observation system and the microclimate observation system in Gongqing Forest Farm, Shunyi, Beijing during the growing season (April?October) from 2015 to 2018, the main driving factors of net ecosystem carbon exchange (NEE) were identified by the random forest importance ranking method. The empirical mode decomposition (EMD) method was used to decompose and reconstruct the NEE and the main driving factors into fluctuation and trend series. Then, four machine learning models, BP neural network, support vector machine (SVM), random forest (RF) and extreme gradient boosting (XG-Boost), were applied to simulate fluctuation and trend series of NEE. After comparing the model performance, the optimal model was selected to reconstruct the NEE time series. Result: 1) The NEE of poplar plantation ecosystem in Gongqing Forest Farm was significantly affected by total radiation and temperature. The soil volumetric water content (5 cm), saturated vapor pressure difference, and relative humidity had weak effects on NEE. The importance rank of environmental factors on NEE was ordered as: total radiation, average temperature, maximum temperature, minimum temperature, soil volumetric water content (5 cm), saturated vapor pressure difference and relative humidity. 2) After NEE decomposition and reconstruction, the models with the best simulation effects for the fluctuation term and trend series were the SVM and the RF model, respectively. 3) Compared with the simulation method without decomposition-reconstruction method, the accuracy of the simulated test set using decomposition-reconstruction method was significantly improved, with R² increasing from 0.520 to 0.676, RMSE decreasing from 1.998 to 1.646 μmol·m^?2 s^?1, and MAE decreasing from 1.578 to 1.273 μmol·m^?2 s^?1. Conclusion: Total radiation, mean air temperature, maximum air temperature and minimum air temperature are the most critical factors affecting the NEE daily variation of poplar plantation ecosystem in the study area. This method proposed in this paper, combining decomposition-reconstruction method with machine learning model, can effectively improve the simulation accuracy of NEE, and provide a new tool for simulating carbon sequestration capacity of forest ecosystem in the “Three North” regions.

Objective: In this study, thecomputational virtual measurement (CVM) method was employed to simulate and measure virtual trees within virtual forest sample plots, aiming to acquire biological parameters that are difficult to measure in reality. The technical workflow integrated the construction of virtual sample plots (VSP), tree modeling, and light simulation to quantitatively analyze the impact of adjacent tree canopy shading on the lighting of target trees, explore the role of leaves in light simulation to optimize VSP technology, and improve the accuracy of lighting analysis. Method: An integrated multi-scale modeling technical framework was constructed. Context Capture Center (CCC) for point cloud reconstruction technique, quantitative structure models (QSM), and Voxel modeling methods were comprehensively applied to achieve cross-scale three-dimensional reconstruction from individual tree organs to community canopies. A physics-based dynamic light transport model was introduced, combined with a digital terrain model (DTM) and a solar trajectory simulation algorithm, to construct a realistic virtual light environment. The dual comparative scenarios of “full day illumination” and “neighborhood shading” were designed to systematically analyze the spatiotemporal change patterns of light energy interception by target trees under the dynamic shading influence of neighboring canopies, and effectively isolate the pure energy loss attributable to shading. Result: The results demonstrated that the shading from neighboring trees caused a solar radiation loss of 35.80% to 45.72% for the target trees, indicating high reliability of this method. The model structure significantly influenced the simulation outcomes: the models incorporating leaves exhibited stronger light attenuation effects. The energy loss rate for sample tree T26 followed the order: CCC model (45.72%) > Voxel model (39.26%) > QSM model (35.80%), confirming that geometric completeness is crucial for assessing shading effects. Canopy structural characteristics also predominantly governed the differences in energy loss. The loss for mature Betula pendula T27 with a sparse canopy (35.80%) was significantly lower than that for young Picea asperata T26 with a dense canopy (45.72%), revealing that young trees are more susceptible to suppression from shading. After data correction, the response characteristics of the different models across various light gradients were clarified, reflecting the influence of light environment heterogeneity on the simulation results. Conclusion: This study successfully achieves precise quantification of the shading effects from neighboring trees in forests by integrating the VSP-CVM methodology. The VSP technology proves capable of accurately reconstructing three-dimensional stand structures and supporting light energy distribution simulations with millimeter-level precision, generating more detailed light environment data compared to traditional measurement methods. This method not only overcomes the limitations of traditional measurement methods, but also provides a new technological means for the study of forest light competition. In the future, it can be expanded to multiple climate zones and forest types to verify its universality, and the photosynthesis process model can be integrated into the meteorological model framework to improve the simulation of light energy utilization processes, providing scientific basis for precise forest management and structural optimization.

Objective: This study aims to investigate the volatile compounds and flavonoid composition in leaves of Dalbergia odorifera, D. cochinchinensis and D. sissoo, and their differences, so as to provide scientific evidence for the development and comprehensive utilization of non-wood forest products derived from Dalbergia species. Method: The solid-phase microextraction method was used to extract the samples, and the GC-MS was used to detect volatile compounds. The relative odor activity values (ROAVs) were calculated and the key odor substances were determined through the odor threshold and the relative content. All identified compounds were queried in Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), and the key bioactive components were screened based on Oral Bioavailability ≥ 20% and Drug-Likeness ≥ 0.10. Meanwhile, relevant targets and associated diseases were further analyzed. Flavonoids were extracted by ultrasonic wave, and LC-MS/MS was applied to detect the flavonoid composition. Result: A total of 80 volatile compounds were identified from D. odorifera leaves, majorly including methyl salicylate (14.52%), benzyl alcohol (11.64%), β-bisabolene (6.08%) and phenylethyl alcohol (5.52%). A total of 31 volatile compounds were detected in D. cochinchinensis leaves, including α-ionone (17.12%), 1-(1-methyl-2-cyclopentenyl) ethenone (16.45%), 3,5-octadien-2-one (16.34%), β-ionone (14.89%), 3,4-dimethylcyclohexanol (7.18%), and dihydroactindiolide (6.35%). A total of 71 volatile compounds were identified from D. sissoo leaves, including β-ionone (10.26%), d-limonene (9.25%), 2-pentylbenzoate (6.50%), and benzyl alcohol (5.35%). A total of 16 flavor compounds were identified from D. odorifera leaves, with the key flavor compounds being α-ionone, methyl salicylate, nonanal, and geranylaceton. Six flavor compounds were identified in D. cochinchinensis leaves, with the key flavor compounds being α-ionone and geranylaceton. Twelve flavor compounds were identified in D. sissoo leaves, with the key flavor compounds being nonanal, geranylaceton, d-limonene, and naphthalene. Four medicinally active compounds were identified in D. odorifera leaves, including (+)-cyclosativene, α-copaene, β-copaene and caryophyllene oxide, while only one active component of farnesyl acetone was identified in D. cochinchinensis leaves, the medicinally active compounds identified from D. sissoo leaves contained (+)-cyclosativene, α-copaene, caryophyllene oxide and dibutyl phthalate. There were 14 types of flavonoids in D. odorifera leaves, majorly including tectorigenin (62.01%), diosmetin (13.68%) and prunetin (6.51%). There were 22 flavonoid species in leaves of D. cochinchinensis, majorly including rutin (30.01%), typhaneoside (24.19%) and kaempferol 3-neohesperidoside (9.58%). However, in D. sissoo leaves, there were 11 flavonoid species, majorly including prunetin (60.80%), rutin (18.02%), and nicotiflorin (7.80%). Conclusion: The leaves of the above three Dalbergia species are rich in volatile compounds, including a variety of flavor and medicinally active components, as well as flavonoids. The findings show their great development potential for applications in pharmaceuticals, fragrances, and personal care products.

Objective: This study investigated the temporal variations of appearance, nutrition and taste quality of rhizome shoots at different harvest periods of time in mulched and no-mulched moso bamboo (Phyllostachys edulis) forests, and comprehensively analyzed the effects of management measures on the quality of bamboo shoots, aiming at providing reference for the cultivation of high quality rhizome shoots. Method: The mulched and no-mulched moso bamboo forests in Changxing County, Zhejiang Province were taken as the research object. Rhizome shoots were harvested in May, July and September to determine their appearance, nutritional substances, flavor substances, and amino acid contents of rhizome shoots. One-way analysis of variance (ANOVA) was used to test the difference significance of the indicators, and the least significant difference (LSD) was applied for multiple comparisons. Principal component analysis (PCA) was used to calculate the comprehensive index of rhizome shoot quality under different management measures, and the comprehensive evaluation was conducted. Result: The basal diameter, length, mass and edible rate of rhizome shoots increased first and then decreased, and they were all higher in mulched moso bamboo forest than those in no-mulched moso bamboo forest. Contents of starch, fat, soluble sugar, protein, and vitamin C increased first and then decreased, while the content of total amino acids gradually increased. In addition, contents of starch, fat, soluble sugar, protein, and vitamin C in mulched moso bamboo forest were significantly higher than those in no-mulched moso bamboo forest at the three harvest times. Contents of cellulose, oxalic acid, tannin, total flavonoids, and total acids decreased first and then increased, while the content of lignin gradually increased. The ratio of sugar to acid increased first and then decreased. The contents of cellulose, oxalic acid, tannin, total flavonoids, and total acids in mulched moso bamboo forest were significantly lower than those in no-mulched moso bamboo forest at the three harvest periods, while the ratio of sugar to acid was significantly higher in mulched moso bamboo forest than that in no-mulched moso bamboo forest. Contents and proportions of bitter amino acids and aromatic amino acids gradually decreased, while the content and proportion of sweet amino acids gradually increased. Contents and proportions of umami amino acids, sweet amino acids, and aromatic amino acids in mulched moso bamboo forest were significantly higher than those in no-mulched bamboo forest, while the content and proportion of bitter amino acids in mulched moso bamboo forest were significantly lower than those in no-mulched bamboo forest. The comprehensive evaluation of rhizome shoot quality showed that mulching management significantly improved the comprehensive index of rhizome shoot quality, and it was significantly higher in July than in May and September. Conclusion: There are significant temporal changes in the appearance, nutrition, and taste quality of rhizome shoots, and it is the best in July. Moreover, mulching management is beneficial for improving the appearance and nutritional contents of rhizome shoots, enhancing their flavor and sweet taste, reducing astringency and roughness, and significantly improving the quality and palatability of rhizome shoots.

Objective: This study aims to investigate the migration routes of Vanellus cinereus (gray-headed lapwing) in the Wuliang Mountain region of Yunnan Province, providing a scientific basis for the conservation of its population and habitats. Method: Population dynamics of gray-headed lapwings in Wuliang Mountain of Yunnan Province were analyzed using bird banding from 1999 to 2024. Six gray-headed lapwings were captured and tracked with satellite transmitters in 2018 and 2023. Kernel density analysis was used to calculate the home range area of each gray-headed lapwing within the wintering ground. Result: According to bird banding monitoring data, the population of gray-headed lapwings in Wuliang Mountain has generally been declining over the past 26 years. Gray-headed lapwings overwinter on Wuliang Mountain in China, the Meghna River and Jibannagar in Bangladesh, and the Belagavi River in India. The birds departed their wintering sites as early as late February and arrived at their summering sites by mid-March. The birds departed their wintering sites no later than early April and reached their summering sites by late April. The migration period lasted between 11 and 21 days. The birds tended to fly at night, and their migration peak was concentrated between 21:00 and 03:00 during spring migration. The home range area of non-migratory gray-headed lapwings was (16.848 ± 11.051) km², with the core range being (2.740 ± 1.90) km². The home range area of migratory gray-headed lapwings was 2 269.366 km², with a core area of 509.122 km². Conclusion: This study has provided detailed information on migration routes of gray-headed lapwing in winter in Yunnan Province, China and south Asia, particularly identifying key summering and stopover sites within China. Their summering sites, excluding the most distant sites in the Inner Mongolia Autonomous Region, are primarily concentrated in Hubei and Anhui Provinces, with additional sites at the junction of Henan, Hubei, and Anhui Provinces. Stopover sites are predominantly located in Hubei and Anhui Provinces, notably at Huangpo Reservoir in Hubei Province, where gray-headed lapwings have been recorded resting for up to 12 days. Given the current overall decline in gray-headed lapwing populations, it is recommended to continue monitoring of population dynamics.

Objective: This study evaluated the potential distribution of global wild Asian elephant habitats under current and future climate change, aiming to provide valuable information for the protection of global wild Asian elephant habitat. Method: Based on 627 Asian elephant activity points and 13 environmental factors such as climate and terrain, the ENMeval package was used to optimize MaxEnt model that was used to evaluate the potential distribution of Asian elephant habitats under current climatic conditions in south Asia, southeast Asia, and southwestern China. Finally, the optimized MaxEnt model was used to evaluate potential distribution of habitat suitability for Asian elephants, and predict habitats of Asian elephants under future climate change. Result: The optimized MaxEnt model had good prediction results, and the AUC value of both the training and testing data was above 0.85. The precipitation of coldest quarter (Bio19) and the temperature seasonality (Bio4) were dominant environmental factors influencing the potential distribution of habitat for Asian elephant, followed by elevation. The simulation results showed that the habitat of Asian elephant was about 149×10⁴ km², accounting for 19.38% of the study area (76.86×10⁵ km²). The habitat of Asian elephant mainly distributed in the southern foothills of the Himalayas, northeastern India, Sri Lanka, southwestern border of China, as well as border areas of Laos, Vietnam, Myanmar and Thailand in southeast Asia, Malay Peninsula, northern Sumatra Island and northeastern Kalimantan Island and other places in Southeast Asia. Under future climate scenarios, the habitat of Asian elephant is showing a decreasing trend compared to the current situation. The habitat of Asian elephants in in southern foothills of the Himalayas and northeastern India will significantly decrease, and there is a trend of northward movement in southern foothills of the Himalayas. Moreover, The habitat of Asian elephant in other regions such as China, Laos, Vietnam and Malaysia will be obviously reduced. Conclusion: Under future climate change, the habitat of Asian elephant would decrease, and the habitat for Asian elephants may move northward in southern foothills of the Himalayas. In the future, we should consider promoting cross-border cooperation, and formulating the strategy of Asian elephant habitat protection.

Objective: This study aims to evaluate the effectiveness of mechanically removing highly flammable fine fuels on both sides of the road in reducing wildfire risk, and to investigate the mechanisms through which this practice influences fire behavior. The findings are intended to provide theoretical and data-driven support for developing scientific fuel management strategies. Method: Prior to the autumn fire prevention period in the Saihanba Mechanical Forest Farm, field plot surveys and laboratory experiments were conducted to measure key fuel parameters (e.g., height, load, moisture content) before and after mechanical removal. The BehavePlus fire behavior modeling system was used to simulate potential fire behavior characteristics before and after removal in various environmental scenarios. Result: Firstly, the mechanical removal treatment was highly effective. The average fuel height along the roadsides was significantly reduced from 0.65 m to 0.18 m. Fuel load decreased by more than 50% in nearly 60% of the sample plots. Secondly, the removal operation directly led to a sharp decline in all fire behavior indicators. The average rates of decrease for surface fire rate of spread, heat per unit area, fireline intensity, and flame length reached 73.00%, 43.75%, 84.81%, and 57.98%, respectively. Notably, the mitigating effect on fire behavior was more pronounced in areas with initially higher fuel heights (e.g., 1.0 m), where the reduction in key fire behavior indicators could exceed 95%. Furthermore, the practice of subsequently clearing the mowed fuels away had superior risk reduction compared to simply mowing without removal. Model simulations also confirms that mechanical removal significantly suppresses fire behavior even under extreme environmental conditions characterized by high wind speed, low fuel moisture content, and steep slopes. Conclusion: Mechanical removal effectively reduces the height and load of flammable fine fuels both sides of forest roads, thereby significantly inhibiting potential fire behavior and lowering wildfire risk. For future management, it is recommended to flexibly adjust the intensity and timing of removal operations based on regional ecological characteristics to achieve the dual objectives of minimizing wildfire risk and maintaining ecosystem stability.

Objective: The genus Acantholyda Costa (Hymenoptera: Pamphiliidae) exhibits high species diversity in China, but the western regions remain insufficient investigation in terms of faunal composition and forest pest status. No species of this genus have previously been reported from Sichuan Province. This study reports and describes new species of Acantholyda collected from forest areas in Sichuan, providing scientific data for the integrated management of forest pests. Method: A classical comparative morphological approach was used to determine the taxonomic position and species identity of the specimens. Diagnostic features were examined and compared with those of closely related species to determine the main distinguishing characters. Result: Four new species of Acantholyda were identified and described: Acantholyda dolichogena Wei, sp. nov., A. fulvostigma Wei, sp. nov., A. kangi Wei, sp. nov., and A. pilosisoma Wei, sp. nov. Detailed morphological descriptions and illustrations of key diagnostic characters were provided for each species. This paper preliminarily discussed the distribution, origin, and evolution of the genus Acantholyda. It was found that species of Acantholyda distributed in East Asia and China had the highest diversity worldwide, accounting for approximately 50% and 29.4% of the known species, respectively. The middle and northern regions of East Asia are the main areas of distribution and diversification of this genus, and are presumed to be the origin center of this genus. Conclusion: The comparative morphological study has confirmed that the four Acantholyda species discovered in the forest areas of Sichuan are new species. This study enriches the understanding of Acantholyda species diversity and provides a scientific basis for biodiversity conservation and forest pest management in China.

Objective: The allocation of carbon emissions and the attribution of carbon storage resulting from international trade in harvested wood products (HWP) are one of the most controversial issues in international climate change negotiations. The latest production method and data from domestic official databases were used to calculate the carbon storage of HWP in China, investigate the changes and driving factors of HWP carbon storage, enhance its role in China’s carbon cycle, quantify its carbon pool function, and improve the accuracy of future predictions regarding carbon storage variations, by which the rational policies and measures were formulated, in order to consolidate China’s position and status in climate change negotiations for addressing climate change and achieving China’s “carbon peaking and carbon neutrality” goals. Method: By applying the method of the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories, combined with the production and trade data of China over the years and parameters suitable for China’s national conditions, China’s HWP was divided into two stages: in-use and disposed. The carbon storage from 1978 to 2022 was calculated by adopting the 2019 revised version of the production approach (PA-2019) based on IPCC first-order decay method, and the driving factors of its changes were analyzed. Result: Affected by national conditions, policies and natural disasters, the level of HWP carbon storage in China was relatively low and fluctuated greatly in the early stage. With the improvement of the economy and the transformation of forest management strategies, the HWP industry has developed rapidly, and the carbon storage of China’s HWP has generally shown an increasing trend, with a accelerating increasing rate. The annual carbon storage of in-use HWP had increased from 6.16 Tg CO₂eq in 1978 to 198.01 Tg CO₂eq in 2022, with a cumulative carbon storage of 2 973.72 Tg CO₂eq. The annual carbon storage of disposed HWP had grown from 1.56 Tg CO₂eq in 1978 to 21.11 Tg CO₂eq in 2022, with a cumulative carbon storage of 290.89 Tg CO₂eq. Over a period of 45 years from 1978 to 2022, the total cumulative carbon storage was 3 264.61 Tg CO₂eq, with the cumulative carbon storage of in-use HWP accounting for 91.09% of total cumulative carbon storage. Among them, wood-based panels contributed the most to the carbon storage, accounting for as much as 68.15%, and played a dominant role in the sensitivity analysis. Sawnwood, and paper and paperboard accounted for 16.38% and 15.47%, respectively. Conclusion: HWP is an important carbon storage resource in China, and holds a significant position in carbon sequestration and emission reduction. Accurately calculating HWP carbon stocks not only provides a data foundation and theoretical support for the compilation of national greenhouse gas inventories, but also helps China to secure a more favorable position in international climate negotiations and contribute to global climate governance.

Objective: To address the low detection accuracy caused by the large scale changes in particleboard surface defects, the coexistence of multi-scale defects, and the positively skewed distribution of defect quantities with respect to defect sizes, an object detection method with adaptive receptive field capability (PBDNet) was proposed in this study. This method was designed with an adaptive receptive field capability to improve the accuracy and efficiency in particleboard surface defect detection. Method: By introducing the spatial splitting and channel fusion strategy (SPDConv) as the downsampling method, PBDNet spatially split feature tensors and concatenated them in channels, thereby reducing information loss during downsampling, and preserving more fine-grained features for defects on the high-frequency side of the positively skewed distribution. This method enhanced the detection ability of the detection model when the number of defects follows a positively skewed distribution with defect scale. Additionally, the feature extraction module (C2f_SD) proposed in PBDNet significantly improved the model's ability to detect defects of different scales by incorporating switchable atrous convolution and differential convolution into the C2f feature extraction module. Result: The comparative and ablation experiments demonstrated that the PBDNet outperformed mainstream defect detection algorithms in terms of both mAP₅₀ and Recall. Compared with YOLOv8s, PBDNet achieved improvements of 4.8% and 6.4% in mAP₅₀ and Recall, reaching 0.881 and 0.840, respectively. Furthermore, the parameter count was reduced by 42.2% while nearly maintaining the inference speed under 3 ms. Conclusion: The PBDNet detection method can meet the requirements for detection of the positively skewed distribution of multi-scale defects on particleboard surface. It provides an efficient, accurate, and edge-deployable automated solution for real-time precision detection, thereby facilitating industrial applications on particleboard surface defect detection.

Objective: This study investigates the impact of new quality productivity in forestry on the efficiency of value realization for forest ecological products and its underlying mechanisms, aiming to provide a scientific basis for local governments to formulate relevant policies. Method: The panel data from 31 provinces (municipalities and autonomous regions) in China between 2010 and 2020 was used to construct a multidimensional indicator system for evaluating new quality productivity in forestry and the efficiency of value realization for forest ecological products. Fixed effects models and mechanism testing models were employed to analyze the impact mechanisms and heterogeneity of new quality productivity in forestry in promoting forest ecological products value realization efficiency. Result: 1) An increase of one unit in new quality productivity in forestry results in a 0.798 2 unit increase in the efficiency of value realization for forest ecological products, with significant contributions from new quality laborers and labor objects. 2) New quality productivity in forestry enhances the efficiency of value realization through pathways such as promoting industrial structure upgrades, facilitating technological innovation, increasing social consumption levels, and accelerating labor transfer. 3) New quality productivity in forestry has a pronounced promoting effect on the efficiency of value realization for forest ecological products in the eastern and central regions, while exhibiting the opposite effect in the western region. In areas with lower consumption levels, new quality productivity in forestry tends to inhibit improvements in value realization efficiency, whereas it significantly promotes efficiency in regions with higher consumption levels. Conclusion: The development of new quality productivity in forestry is crucial for promoting the market value of forest ecological products. Policy decisions should consider the heterogeneous characteristics of regions and consumption levels, employing differentiated and diversified measures to synergistically promote the efficient transformation of green mountains and clear water into gold and silver mountains.

Objective: This study aims to investigate the influence and mechanisms of the protection and restoration efficiency of mountains, water, forests, fields, lakes and grasses on the development of new quality productivity in forestry, so as to provide a scientific basis for the protection and restoration of mountains, water, forests, fields, lakes and grasses to enhance the level of the development of the forestry new quality productivity, and provide new ideas and perspectives for promoting the forestry high-quality development. Method: With the panel data from 31 provinces (autonomous regions, municipalities) in China from 2012 to 2021, the global super-efficiency SBM model based on non-expected output was used to measure the protection and restoration efficiency of mountains, water, forests, fields, lakes and grasses. The entropy method was used to construct the evaluation index system to assess the level of development of forestry new quality productivity in terms of labors, labor objects and means of labor. The impact and mechanism of protection and restoration efficiency of mountains, waters, forests, fields, lakes, and grasslands on the development of forestry new quality productivity were empirically analyzed through mediation effect models. Result: 1） The protection and restoration efficiency of mountains, water, forests, fields, lakes and grasses and the development level of the forestry new quality productivity in 31 provinces (autonomous regions and municipalities) of China have shown a rising trend year by year, and have shown obvious regional differences. 2）The direct impact analysis shows that the protection and restoration efficiency of mountains, waters, forests, fields, lakes and grasses can promote the development of the forestry new quality productivity. 3）The indirect impact analysis shows that the protection and restoration efficiency of mountains, waters, forests, fields, lakes and grasses can promote the development of the forestry new productivity by improving the level of forestry technological innovation, upgrading the structure of the forestry industry and government intervention. 4）The heterogeneity analysis shows that, as the level of forestry new quality productivity continues to rise, the impact of the protection and restoration efficiency of mountains, water, forests, fields, lakes and grasses on forestry new quality productivity is becoming more and more significant. The protection and restoration efficiency of mountains, water, forests, fields, lakes and grasses can significantly promote the development of forestry new quality productivity in eastern and central China. Conclusion: From 2012 to 2022, the protection and restoration efficiency of mountains, water, forests, fields, lakes and grasses in 31 provinces (autonomous regions and municipalities) of China has continued to improve, and the level of forestry new quality productivity has risen. The increased level of forestry technological innovation, the upgraded structure of the forestry industry and government intervention have contributed to the development of forestry new quality productivity to varying degrees. Meanwhile, the protection and restoration efficiency of mountains, water, forests, fields, lakes and grasses can promote the development of the forestry new quality productivity, and we should focus on the systematic management, optimize resource allocation, and strengthen the guidance of social capital investment. We also should focus on the frontiers of science and technology, strengthen the investment in forestry science and technology, optimize and upgrade the structure of the forestry industry, and emphasize policy guidance. It should be further adapting measures to the local conditions and target-oriented policy, implementing the differentiated development strategy and enhancing the ecological protection and restoration of mountains, water, forests, fields, lakes and grasses to empower the development of forestry new quality productivity.

Objective: This study aims to explore how joint household management affects forestry management inputs, for enhancing operational efficiency and achieving sustainable development, so as to address the dilemmas faced by individual household operations under the background of the collective forest tenure reform. Method: Based on the monitoring data of collective forest tenure reform, an endogenous switching regression model was adopted to deeply analyze the impact of joint household management model on capital and labor inputs per unit area within a counterfactual analysis framework. Meanwhile, the moderating effect of non-farm employment on the relationship between joint household management and forest management inputs was explored, and the heterogeneity among farmers was analyzed. Result: 1) Under the counterfactual analysis framework, the treatment effect of joint household management on capital input per unit area is ?0.786, and the treatment effect on labor input per unit area is ?0.054, indicating that joint household management can significantly reduce both capital input and labor input per unit area. 2) Non-farm employment positively moderates the relationship between joint household management and capital/labor input per unit area. 3) Joint household management reduces both self-invested labor and hired labor per unit area, with a particularly notable decrease in self-invested labor. In addition, the provision of socialized forestry services effectively alleviates information asymmetry, thereby alleviating opportunistic behaviors. 4) The results of heterogeneity analysis show that farmers with small-scale operations, low incomes, and small-group joint households have more significant reduction effects in forest management input. Conclusion: The government should promote the scaling-up and specialization of forestry production and management, strengthen the interaction between non-farm employment and forestry management, improve the forestry socialization service system, and guide joint household management entities to optimize the interest connection mechanisms. Through differentiated strategies, the government should ensure the shared interests of all parties to promote the optimal allocation of forestry resources and the improvement of economic benefits.

Objective: The aim of this study is to test whether there is any bias in the DBH measurement data of large survivor trees in continuous forest inventory, and to provide scientific basis for improving the measurement method. Method: Based on the DBH measurement data of 2501 large survivor trees in forest sample plots from the continuous forest inventory in Beijing from 2020 to 2024, the tree growth rate models and difference significance test method were used to test whether the difference between measured and estimated DBH growth was significant and there was bias in DBH measurement data, and the relationship between the bias size and interval length (1–8 years) was analyzed, and the data in Hebei Province was employed for verification. Result: The results showed that there was a significant bias in the DBH measurement data of large survivor trees from the inventories in Beijing from 2020 to 2024. The total bias of measured DBH growth was 38.0%, among which the bias of 8-year interval data was 21.9%, and that of 1-year interval data was 88.7%. The DBH measurement data of large survivor trees in Hebei Province from 2020 to 2024 also confirmed that the total bias of measured DBH growth was 50.0%, and the bias of five sets of plots ranged from 32.8% to 86.6%. Conclusion: There are positive biases in the DBH measurement data of large-diameter survivor trees in some extent, and the size of bias is highly correlated with the interval length. The shorter the interval length, the greater the bias in DBH measurement data. It is suggested to develop tree DBH growth rate models based on previous inventory data, and reasonably set the upper limit for warning according to the predicted DBH growth. For very large survivor trees over a certain size (e.g. 50 cm), the predicted estimates from models can be directly used as the measured DBH.

The development of new high and stable-yield Vernicia fordii (tung oil tree) varieties is of great significance for the high-quality development of the tung oil industry. ‘Yahong 1’ is a new variety of tung oil tree developed from natural variation of the ‘Duinian tung tree’ in Guizhou Province, China. It is a purely female plant with multi-spike racemes. The fruits are round, borne on short stalks, with 15?20 fruits per branch and an average of 4.8 seeds per fruit. The seeds are broadly ovate in shape. Each fruit weighs 49.0 g on average, and a single plant produces 36.67 kg of fruit, equivalent to 10.0 kg of dry tung seeds per plant. ‘Yahong 1’ variety grows rapidly, demonstrates high and stable productivity, and exhibits tolerance to poor soils and seasonal droughts, making it an excellent new variety for large-scale tung oil production.