Objective: This study aims to explore the effects of thinning intensity on understory vegetation, soil microbial community and multifunctionality in a Larix kaempferi (Japanese larch) plantation, so as to provide a theoretical basis for sustainable management of plantations. Method: A 16-year-old Japanese larch plantation in the montane region of eastern Liaoning Province was targeted, and three thinning intensities in standard plots were conducted in April 2019, namely control (2 000 trees·hm^?2; canopy density 0.89); 30% thinning (1 404 trees·hm^?2; canopy density 0.78), 45% thinning (1 106 trees·hm^?2; canopy density 0.69). In July 2020, understory vegetation characteristics were investigated at the peak growth season, and soil samples were collected in spring, summer and autumn. Soil physicochemical properties, enzyme activities, and microbial community (fungi and bacteria) diversity and composition were measured. Soil multifunctionality was calculated based on 15 soil physicochemical properties and enzyme activities parameters related to C, N and P cycles. Result: 1) Compared to the control, 45% thinning intensity significantly increased the diversity of understory vegetation, soil available nutrients, enzyme activity and fungal diversity as well as soil multifunctionality and the impact on soil properties was particularly pronounced in summer. The 30% thinning intensity significantly decreased soil multifunctionality in spring and summer, and had no significant impact on understory vegetation. 2) Thinning significantly affected the relative abundance of dominant phyla and classes of soil fungi, but had no significant influence on the relative abundance of dominant phyla and classes of soil bacteria. Especially, 45% thinning intensity significantly increased the relative abundance of Ascomycota in summer and significantly decreased the relative abundance of Basidiomycota in summer and autumn. The relative abundance of dominant phyla and classes of bacteria was mainly affected by season. 3) Correlation analysis showed that there were significant and positive correlations between the biomass and diversity of understory vegetation, fungal richness and soil multifunctionality. Structural equation model indicated that 45% thinning intensity had a significant direct and positive effect on soil multifunctionality, and had an indirect positive effect on soil multifunctionality by changing fungal community composition. Conclusion: Soil fungal community in Japanese larch plantation is more susceptible to thinning, while bacterial community is significantly affected by season. The 45% thinning intensity (canopy density 0.69) is more conducive to maintain the growth and development of understory vegetation, fungal diversity and soil multifunctionality than the 30% thinning intensity (canopy density 0.78) in 16-year-old Japanese larch plantation.

Objective: In this study, we comprehensively measured for the first time the embryo-free rate (EFR) and the main components of embryonic and embryo-free seeds of Ginkgo biloba clones, screened out high embryo-free germplasm resources of G. biloba clones, and conducted in-depth research on the causes and mechanisms of embryo-free phenomenon, in order to provide reference for further development and utilization of G. biloba industrial resources. Method: The seeds of 47 ginkgo clones were randomly collected from the female plants in the sole national Ginkgo Elite Variety Base in Pizhou City, Jiangsu Province. After sampling, the seed coat was peeled off one by one to observe the presence or absence of seed embryos, to investigate the embryo-free phenomenon, and to calculate the EFR. According to relevant national and industry standards, those ginkgo seeds were distinguished between embryo-free seeds and embryonic seeds. And their main nutrients were measured. Result: The EFR of the 47 ginkgo clones ranged from 17.16% to 100%, with an average of 59.74% and a median of 59.02%. There were significant differences in EFR among the clones determined by ANOVA. The fruit shape index (FSI) of these ginkgo clones ranged from 1.19 to 1.81, with a significant correlation coefficient of -0.285 between the FSI and the EFR. Twelve ginkgo clones were selected to differentiate the variety groups, and it was found that the fat, soluble sugar, starch, soluble protein, total amino acids, total flavonoids and terpene lactones of embryo-free seeds were not significantly different from those of embryonic seeds; while the contents of ginkgotoxin, Ca and Fe were significantly lower than those of embryonic seeds. The EFR was also strongly correlated with starch and terpene lactone content, with correlation coefficients of 0.698 and ?0.599 respectively. Conclusion: The scientific understanding of the processing and use of ginkgo seeds has been deepened from the perspective of the presence or absence of embryonicity. The embryonic relationship of the main clones of G. biloba is discovered, and excellent ginkgo germplasm resources with an EFR of over 90% or 100% are found. We have distinguished between embryo-free and embryonic seeds of those clones, and found differences in their main nutritional components, minerals, and main secondary metabolites, as well as their correlations. This study confirms that the EFR of G. biloba was highly significantly positively correlated with its starch content and negatively correlated with its terpene lactone content, providing more accurate scientific and technological support for the development of G. biloba seed industry.

Objective: This study was carried out in black locust (Robinia pseudoacacia) forest in Huangtuliangzi, Pingquan City, Hebei Province, China, to verify the polymorphism of developed SSR primers of black locust, explore the distribution pattern of black locust sprouts, and provide a theoretical basis for artificial promotion of sprouting regeneration of black locust forests. Method: Three sample plots with obvious sprouting of black locust were selected in Huangtuliangzi forest farm of Pingquan City, Hebei Province. The genetic relationship of 125 black locust strains was identified by using 9 pairs of SSR primers. The traditional sample plot investigation method and the adjacent lattice method with variable scales were used to divide five sampling scales (5 m×5 m, 5 m×10 m, 10 m×10 m, 10 m×15 m, 20 m×30 m), calculate the deviation index (C) and its t-test, Cassie index (CA), average congestion (m*), negative binomial index (K), green index (GI) and agglomeration index (PAI), and then judge the pattern and scale. Result: The 9 pairs of primers had high polymorphism, and the average polymorphism information content was 0.76. In the three plots, a total of 73 genotypes, and 76 clonal ramets of black locust were identified. The distribution pattern of black locust clonal ramets from the cluster distribution tended to random distribution with the increase of sampling scale. The cluster distribution was the strongest when the sampling scale at 5 m×5 m. Conclusion: Based on the combination of SSR molecular markers and ecological investigation, this study explored a new method for studying the sprout distribution pattern, clarified the sprout distribution pattern of mountain black locust, and further understood the sprout regeneration theory of black locust. The distribution pattern of sprouts of black locust forest after felling is cluster distribution under no disturbance condition. The concentration and distribution of sprouting plants in a small area will result in a single genotype, which is not conducive to population diversity. It is suggested to make thinning of individuals that are too close to each other and affect normal growth and development, in order to ease competition and improve stand quality.

Objective: Based on the taper data of Pinus sylvestris var. mongolica and Larix gmelinii, the ordinal nonlinear least squares method (ONLS), quantile regression (QR), the fixed part of mixed effects model (FIXED) and generalized additive model (GAM) were compared by prediction accuracy of the diameter and total volume. Method: The data of 187 Pinus sylvestris var. mongolica and 283 Larix gmelinii with different stands in Mohe Forestry Bureau, Daxing'an Mountains, were studied. 33 commonly used taper equations in forestry were fitted. The taper equation with higher accuracy was selected as the basic model of ONLS, QR and FIXED. In addition, the commonly used variables for describing the stem shape were used to construct GAM. At the same time, transformed variables such as square, square root and other conversions were considered. The four methods were fitted using R software. And they were compared by mean error (ME), root mean square error (RMSE), percentage root mean square error (RMSE%) and coefficient of efficiency (R²). A leave-one-out cross-validation method was used to validate the prediction accuracy of diameter and total volume of different modelling methods. In order to show the effects of each modelling method more intuitively, two trees with different sizes were randomly selected from the two tree species for stem simulation. Result: 1) The fitting results showed that ONLS, QR and FIXED based on Kozak (2004) as well as constructed GAM could fit Pinus sylvestris var. mongolica and Larix gmelinii stem well. 2) The results of cross-validation showed that the GAM is better than ONLS, QR and FIXED for two species. 3) The GAM for volume estimation of the two tree species was consistent with diameter, that is, the accuracy of GAM estimation is better than other methods. Compared with the ONLS, the RMSE of volume prediction of the GAM decreased by 5.6% and 11.3% for Pinus sylvestris var. mongolica and Larix gmelinii, respectively. 4) The ONLS, QR, FIXED and GAM had similar simulation effects for large trees after simulating the stem of these two species with different sizes, and they can simulate the large stem form well for both species. For small trees, ONLS, QR, FIXED and GAM were quite different. The GAM can simulate the small tree stem well for these two species. Conclusion: The GAM has the highest accuracy for diameter and volume prediction. When prediction is the main purpose, the GAM constructed in this study can be used for diameter and volume prediction for Pinus sylvestris var. mongolica and Larix gmelinii by simple programming. It can be used as an accurate method to predict stem shape.

Objective: This study aims to investigate the ionomic responses in four cultivars of Salix integra under cadmium (Cd) stress, so as to provide a theoretical basis for selecting high Cd-enriched S. integra, and improving the remediation efficiency for heavy metal contaminated soil. Method: A hydroponic experiment was conducted to analyze the variation of Cd, macro elements (N, P, K, Ca, Mg), and trace elements (Fe, Zn, Cu, Mn, Mo, Se) contents in roots, cuttings, new branches and leaves of four cultivars of S. integra under 0, 10, and 50 μmol·L^?1 of Cd(NO₃)₂ treatments. Combined with principal component analysis, correlation analysis and partial least squares regression analysis were performed to identify the elemental contribution of ionomic variation in different tissues under Cd stress and influence on accumulation of Cd and translocation of the major elements in S. integra. Result: 1) The coefficient of variation (CV) of macro elements, especially N, was significantly smaller than that of the other elements, and the CV of Cd in leaf tissue was significantly higher than that in the other tissues. The CVs of divalent cations such as Mn, Zn and Fe under Cd stress were all greater. 2) PCA analysis revealed that 78.3% of the total variation in the ionome of S. integra was caused by the tissue types, among which Zn, Fe, Cu, Mn and Mo were important components of the variation in the ionome of S. integra. 3) The degree of interference of Cd treatments on different tissue ionome was: root > leaf > new branch > cutting. Results also showed that Cd content in the leaves was significantly and positively correlated with Fe and Mg; Cd content in the new branches and cuttings was significantly and positively correlated with N and Se; Cd content in the roots was significantly and positively correlated with Ca, Cu and Se. Cluster analysis and partial least squares regression confirmed that N, P, Ca, K, Mn, Fe, Mg and Mo played an important role in Cd translocation in S. integra. Conclusion: The ionomic variation in S. integra caused by Cd stress mainly originates from the differences among tissue types. In the same tissue, the ionomic variation mainly originates from Cd stress. Moreover, the main elements that cause ionomic variation vary in different tissues. The transport of Cd in S. integra is affected by ionomic variation, among which the macro elements of N, P, K, Ca, Mg, and the trace elements of Mn, Fe and Mo play an important role in the transport of Cd in S. integra.

Objective: The growth and development patterns of Eucommia ulmoides kernels, and the correlation between the dynamic changes of oil body and the oil content in the kernels were studied. The change patterns of fatty acids in kernels and the interaction between various fatty acids were clarified, so as to provide theoretical reference for timely harvestingE. ulmoides fruits and breeding new varieties with high oil and high quality. Method: The kernels of E. ulmoides'Huazhong No. 8' at different development stage were used as experimental material. Dynamic changes of oil bodies in kernels were observed by Nile red staining and confocal laser scanning microscopy, and the content and composition of fatty acids in E. ulmoides kernels were determined by GC-MS. Result: 1) The growth and development process of E. ulmoides kernels was able to be divided into three periods : rapid growth period (late May to early July), slow growth period (early July to late August) and mature period (after early September). The shape changes of kernels in rapid growth period were the most obvious, and the shape changes of kernels in other two periods were not obvious. 2) With the development of kernels, the number of oil bodies gradually increased and continued to spread to the central cell. The oil content of kernels was positively correlated with oil body content and showed a 'S' shape change trend. 3) A total of 9 fatty acids were detected during kernels development, including palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid. The content of unsaturated fatty acids showed a trend of gradual increase with kernels development, and reached the maximum value (91.64%) at the beginning of September, of which the content of linolenic acid was as high as 63.26%. Correlation analysis showed that palmitic acid was positively correlated with stearic acid and oleic acid, and linolenic acid was negatively correlated with palmitic acid and oleic acid. Conclusion: The growth and development rate of E. ulmoides kernels shows a trend of first fast and then slow. There is significant positive correlation between oil body content and oil content in kernels. There are abundant types of fatty acids in kernel oil, among which the content of unsaturated fatty acids that are beneficial to human body has obvious advantages.

Objective: This study aims to explore the characteristics of volatile organic compounds (VOCs) in the leaves of different walnut cultivars at different growth stages, clarify the VOCs components and compare the variation in the VOCs components at different growth stages to establish the odor fingerprints of volatile organic compounds in walnut leaves at different development stages, so as to provide reference for the utilization of walnut leaf germplasm resources. Method: Gas chromatography-ion mobility spectrometry (GC-IMS) was used to detect the volatile components in the leaves of 8 walnut varieties at 4 different growth stages (May, June, July and August). Two-dimensional GC-IMS spectrum, fingerprint and principal component analysis (PCA) were applied to compare the volatile components of walnut leaves at different growth stages. Result: A total of 102 volatile components were detected by GC-IMS in the leaves of 8 walnut varieties at 4 growth stages, including 12 terpenes, 30 esters, 24 aldehydes, 19 alcohols, 9 ketones and 8 others. Among them, 32 volatile substances were detected in walnut leaves in May, June, July and August, including aromatic alcohols, nonanal, cineolol, cineolol dimer, ethyl hexanoate, ethyl hexanoate dimer, amyl acetate, ethanol, 2-hexenal, hexanal, heptanal, ethyl isobutyrate, ethyl propionate, 2-methylbutyraldehyde, isovaleraldehyde, ethyl acetate, ethanol, ethyl isovalerate, 3-methyl-1-pentanol, 1-pentanol, hexyl butyrate and propyl butyrate. The developmental degree of walnut leaves had a great effect on its volatile components. The total content of volatile compounds in Juglansregia‘Wen185’, J. regia‘Xinxin2’, J. regia‘Zhipi’, J. regia‘Robert Liver-more’ and J. regia‘Zijin’ first increased and then decreased from May to August, and reached the highest in June. The total content of volatile compounds in Carya cathayensis, J. nigra and J. microcarpa had an upward trend from May to July, and then a downward trend from July to August with the highest in July. The types and contents of volatile substances in walnut leaves changed obviously at different growth stages and some volatile substances decreased gradually with the development of walnut leaves. Conclusion: There is a little difference in the species of volatile components in walnut leaves at different growth periods, but the relative content is very different. Terpenes and esters first increase and then decrease with the development of walnut leaves, while alcohols first decrease and then increase with the change of growth period. The research results can provide reference for utilizing walnut leaf germplasm resources.

Objective: Due to the complexity and strong concealment of lightning-caused forest fire occurrence, it is difficult to monitor and early warning. For most available forest fire forecasting models, although main meteorological factors are taken into account the models, their adaptability and precision are still relatively low. In this study, based on the long-term multi-sources data, the driving factors of lightning-caused forest fires were analyzed, and a dynamic lightning-caused fire forecasting model with high spatial resolution was built by using machine learning method, to provide support for the fire prevention and control. Method: The spatial and temporal distribution of lightning-caused fires from 2010 to 2020 was analyzed. Multi-source data such as ground-based lightning observations, satellite data, meteorological reanalysis data and DEM data were used to extract 18 driving factors from 4 categories (i.e., lightning, meteorology, vegetation and terrain). The characteristics of each driving factor and the relationship with lightning-caused fires were studied. The driving factors of forest lightning-caused fire records and randomly generated non-lightning fire spots were extracted to establish our initial training sample dataset. Driving factors were selected by calculating feature importance and correlation matrix. Based on the optimized training sample dataset, three integrated learning models, namely, gradient ascending decision tree (GBDT), random forest (RF) and extreme random tree (ERT) were trained and evaluated, respectively. The model with the best performance was used to forecast forest lightning-caused fires in Daxing’ anling Mountains. Result: The results showed that from 2010 to 2020, the maximum and minimum number of lightning fires occurred in 2015 and 2012, respectively, mainly in May, June and July, and the occurrence period was mainly concentrated from 10:00 to 17:00. The areas with high lightning-caused fire density appeared in Mohe County, Tahe County, Xinlin District and Huzhong District. The spatial distribution of lightning was consistent with that of lightning-caused fires to a certain extent, but the more lightning number might not lead more lightning-caused fires. In 2011, the maximum number of lightning occurrences was 114 632, but only 11 lightning-caused fires. Under the following conditions: lightning intensity in –20– –40 kA, steepness ranged of – 4– –8 kA·μs^?1, relative humidity less than 40%, precipitation less than 4 mm, temperature more than 29 ℃, atmospheric pressure in 91–95 kPa and wind speed in 1–3 m?s^–1, lightning fires were more prone to occur. NDVI (normalized vegetation index), GPP (total primary productivity), Et (evapotranspiration), and NPP (net primary productivity) were positively correlated with the occurrence of lightning-caused fires. Lightning-caused fires occurred more frequently at altitude of 300–900 m and slope of 0–12°, and aspect had little effect on the occurrence of lightning fires. After feature selection, the remaining 13 features were involved in the model construction of the three ensemble learning algorithms, and the comparison showed that the ERT prediction effect was the best. The AUC value of ERT model reached 0.97, and the precision, recall and F1 score values were all higher than GBDT and RF models. The high-risk region of lighting fires predicted by ERT model had a good agreement with the location of the actual lightning fire spots. Conclusion: The multi-sources big data, especially satellite observation data, are used to obtain more potential driving factors related to the occurrence of lightning-caused fires. Combined with the advantages of machine learning method, our forecasting model of forest lightning-caused fires well performs on the high-risk region prediction of lightning-caused fires in Daxing’ anling Mountains, which has good generalization ability, good adaptability and high spatial resolution.

Objective: Among the current forest fire detection methods, the research based on deep learning is the most active. However, when dealing with real scenes, the model detection effect is often poor due to insufficient samples of forest fire, imbalanced distribution of categories and weak expression ability of scenes, et al. To alleviate this problems, we presented a newly developed data augmentation method called self-adaptive mix augmentation (SMA). Method: This study takes UAV(unmanned aerial vehicle) forest fire images collected from Chongli district, Zhangjiakou city, Hebei Province as the research object. The work is as follows: 1) Preprocess the UAV video to construct the original data set. 2) Use methods such as category statistics and annotation box centralization to analyze and find out the problems existing in the data, such as: nimiety of small targets, unbalanced target distribution and scattered annotation box size. 3) For the problem of imbalanced categories, we introduced self-adaptive parameters to achieve the dynamic adjustment of samples. 4) In order to ensure the effectiveness of cross-sample information fusion, IOA(intersection over aim) was proposed as a judgment threshold to give a reasonable reference value. 5) According to the principle of control variables, we designed 12 ablation experiments with UAV data as samples, and compared the results of forest fire detection of original sample, ordinary data augmentation, Mosaic and SMA methods in SSD, YOLOv3 and YOLOv4 mainstream algorithms, respectively. 6) MAP(mean average precision) was selected as the index to evaluate the results of different data augmentation methods in the same algorithm. Result: The results of ablation test showed that in SSD, YOLOv3 and YOLOv4 algorithms, the MAP performance of SMA method was 48.16%, 82.02% and 67.79%, compared with the original data, it increased by 12.14%, 11.50%, 36.83%, compared with traditional random augmentation, it increased by 11.95%, 4.86% and 16.33%, compared with the Mosaic method, it increased by 1.06%, 18.24%, and 1.79%. Conclusion: Traditional data augmentation methods did not fully explore the information contained in samples in forest fire data set. The SMA method in this study introduces self-adaptive parameters to alleviate the problem of sample imbalance, and the introduction of IOA achieves cross-sample fusion. The experimental results showed that the SMA method improves the MAP performance of SSD, YOLOv3 and YOLOv4 algorithms compared with the traditional method, which proves the effectiveness of SMA method on forest fire data set.

Objective: This study aims to reveal the pattern of ant species diversity in the middle of Tianshan Mountain, and provide a basis for ecological restoration and species diversity protection in Tianshan Mountain area. Method: The species diversity of ants in the middle of Tianshan Mountain was surveyed by plot sampling method. The sampling adequacy was tested by R4.1.1 software, and the α diversity indexes and Jaccard community similarity coefficients were calculated. Pearson correlation between ant diversity indexes and habitat factors was analyzed by SPSS 24 software. Result: A total of 11 767 ant individuals were collected in the middle of Tianshan Mountain area, and they belonged to 2 subfamilies, 15 genera, and 27 species. The species richness, diversity index and evenness index of ant communities on the northern slope were higher than those on the southern slope. With the increase of altitude, the α diversity indexes of various plots on the southern and northern slopes showed a multi-domain effect or a middle-domain effect phenomenon. The similarity (0.222 2) between ant communities on the southern and the northern slope was at an extremely dissimilar level, and the similarity level between ant communities at various plots on both the southern and northern slopes was generally lower. The similarity (0.000 0–0.416 7) between ant communities from various vegetation was at an extremely dissimilar to moderately dissimilar level. Correlation analysis found that species richness and diversity index had a significant negative correlation with altitude, and a significant positive correlation with tree canopy density. Conclusion: The α diversity of ant community in the middle of Tianshan Mountain is mainly determined by altitude and air temperature, meanwhile related to humidity, vegetation properties and human disturbance factors. Good vegetation can provide sufficient food resources and habitat for the ant community, and ants prefer to live in the middle to low altitude zone with high vegetation coverage and hot and moist climate. The ant communities in the vertical zones of northern and southern slopes and from various habitats are significantly differentiated. The above results have important reference value for ecological restoration and species diversity protection.

Objective: The present study aims to clarify the species of the parasitoids in the galls of Cerroneuroterus yukawamasudai and deconstruct the biological characteristics of the predominant parasitoid species, so as to provide a scientific basis for biocontrol of the gall wasp. Method: Species of parasitoids and biology of a dominant parasitoid Torymus sp. in the asexual gall of C . yukawamasudai were surveyed by field investigation, indoor anatomy and laboratory experiment. Result: There were three parasitoid species in the asexual gall of C. yukawamasudai : Torymus sp., Pteromalus sp. and Chouioia sp. Among them, Torymus sp. was predominant parasitic natural enemy. The parasitoid occurred one generation in a year, and the larvae overwintered in the host asexual galls. The overwintering adults of Torymus sp. started emergence in late October, and laid eggs in the asexual galls. The parasitism rates of Torymus sp. to C . yukawamasudai were 18.00% and 21.86% in 2019 and 2020, respectively. Eclosion period of the parasitoid lasted for 81–85 days. Peak eclosion periods of male and female parasitoid were in mid-November and late November, respectively. The eclosion time was concentrated between 8:00–12:00 in every day, and its sex ratio (female/male) was 1︰2. The parasitic wasp was good at jumping and had the habit of feign death. Adults could mate on the same day after they emerged from the gall, and mated multiple times. Honey water supplementation significantly extended the longevity of male parasitoid, but not female parasitoid. Conclusion: Torymus sp., Pteromalus sp. and Chouioia sp. are found in the galls of the asexual galls of C. yukawamasudai . Parasitism rate of Torymus sp. to C. yukawamasudai is the highest, stating that Torymus sp. is the dominant species of parasitic natural enemies. Torymus sp. can be used as an important means to control C. yukawamasudai.

Objective: Xingkai Lake located in Heilongjiang Province is an important international migration corridor for waterbirds in eastern China. Comparative analysis on the changes in waterbird community structure in different years can aid in providing basic data for waterbird conservation in Xingkai Lake. Method: The waterbird data collected from 43 monitoring stations in 2014—2015 and 2021 were comparatively analyzed. The Shannon-Wiener diversity index, Pielou evenness index, and TBI index were used to compare the differences in richness and community structure of waterbirds in different areas and habitats between the two periods. In combination with temperature and water level data, the relationship between these differences and climate was examined. Result: The results showed that a total of 665 504 waterbirds were found in Xingkai Lake, belonging to 71 species, 12 families, and 7 orders, totaling 665 504 individuals. While there was no significant difference in the number of species between 2014—2015 and 2021, the number of total individuals almost doubled, mainly due to increase of geese, ducks and gulls, and however the number of cranes, plovers, and rails showed a decreasing trend. Waterbird species and individual numbers were higher during the migration periods, in March-April and September-November, and lower during the breeding period. The four areas of Xingkai Lake had similar community structures, but with some differences: Longwang Temple had the highest number of species and individuals, showing an increasing trend. Hugang and Dongbeipaozi had relatively lower evenness, but increasing number of species. Qingshan Reservoir had the lowest number of waterbirds but the highest diversity and evenness, albeit with a decreasing trend of species. Marshes had the highest number of species, whereas mixed habitats had the highest diversity and number of waterbirds. Farmlands had the lowest evenness, and the number of species and individuals increased in the above three habitats. In contrast, the species and number of waterbirds in shrubs, grasslands, and wetlands all decreased, with the number of individuals in wetlands decreasing the most. Conclusion: Overall, the increase in the numbers of waterbirds in Xingkai Lake is a positive sign, and related to the better management of the reserve in recent years, as well as the increase in temperature and water level. But Xingkai Lake is still under the pressure of increasing farmland and decreasing marsh. It is suggested to adopt standardized methods for long-term waterbird monitoring, and strengthen the management and protection of key areas in response to the distribution of waterbirds in different periods.

Objective: Ancient ginkgo trees are an important part of social culture and urban ecosystem. This study aims to reveal the centre rot characteristics and influence factors of ancient ginkgo trees, to put forward targeted resource management and protection strategies of ancient ginkgo trees, and hence maintain the ecological and cultural heritage and the health of ancient tree resources. Method: In this paper, an ARBOTOM tree trunk tomography scanner was used to randomly select 100 ancient ginkgo trees in Beijing for heart rot measurement and on-site investigation. The images of the heart rot were divided and calculated, and the characteristics of the trunk heart rot were analyzed. The correlations between rot and growth index, health index, morphological index and environmental index were studied, to explore the relevant influencing factors of heart rot of ancient ginkgo trees. Result: The result showed that the number of different centre rot grades of ancient ginkgo trees in Beijing from large to small was grade 3 > grade 2 > grade 1 > grade 4 successively. The frequency of centre rot initial points in three different positions of the trunk from high to low was sapwood (Y) > pith (S) > middle part (X). The probability of centre rot area at different locations was pith (48.75%) followed by the middle part (41.63%) and then sapwood (37.06%), showing a gradual decline from inside to outside. Among the influence factors, the diameter at breast height ( R²=0.376), tree-age grade (R²=0.217), tree height (R²=0.038), trunk disease (R²=0.268), trunk insect pest (R²=0.230), bark damage (R²=0.224) and soil density (R²=0.024) had a significant correlation with centre rot (P < 0.01). The crown height ratio, root system growing space and crown growth space had significant correlation with the heart rot index ( P < 0.05). Conclusion: The centre rot of ancient ginkgo trees occurs mainly in the pith and sapwood regions of the trunk. Although the initial centre rot is mainly caused by the infection of trunk sapwood, the harm caused by heart rot occurred in the pith is more serious. The trunk health of ancient ginkgo trees gradually declines as the trees grow, and the decline will accelerate when the rot or hollow happens to the trunk. Furthermore, the centre rot of ancient ginkgo tree is significantly correlated with diameter at breast height, tree height, tree-age grade, trunk diseases and pests and bark damage, and the environmental indexes (soil density, root system and canopy growth space) may influence the centre rot of ancient ginkgo trees to some extent. Therefore, it's necessary for managers to timely evaluate the health status of ancient ginkgo trees and strengthen the internal centre rot detection of ancient ginkgo trunk health. The growth status of ancient trees can to a certain extent be used as a reference to evaluate the internal health status, so as to efficiently evaluate the health status of the ginkgo tree population. In addition, in terms of management, it is necessary to pay attention to prevention and control of diseases and pests on ancient ginkgo trees and repair of bark damage, reduce the occurrence of environmental damage, expand the growth space of ancient ginkgo trees within the achievable scope and timely loosen the soil to ensure adequate growth space and nutrient supply.

Objective: Using lignin with different structural units isolated from straw, reed and bamboo as the research material, the dynamic behavior between isolated lignin and enzyme adsorption was studied based on quartz crystal microbalance with dissipation (QCM-D) in situ and in real-time. The results obtained could provide targeted regulation for the efficient utilization of lignocellulose. Method: The chemical composition of raw materials was determined according to the standard method, the structural units of isolated lignin were characterized by infrared, alkaline nitrobenzene oxidation and gel permeability chromatography. The surface morphology of lignin film was detected by using an atomic force microscope, and the adsorption behavior of cellulase on lignin film was studied by QCM-D. Result: The isolated lignin was GSH type with high purity, the sugar content was about 10%, and their molecular weight was close, about 5 000. The nitrobenzene oxidation results indicated that structural units of isolated lignins were different, uncondensed units yield of bamboo lignin was highest, 444.4 g·kg^?1, and its S/G mole ratio was 1∶0.6. The lignin S/G ratio in reed was 1∶1.1, as well as rice straw. Bamboo lignin film showed the fastest adsorption rate of cellulase, and its adsorption amount was also the maximum via QCM-D analysis. The adsorption rate and maximum adsorption amount of cellulase in reed and straw lignin films were similar. After stopped the cellulase injection, the lignin film was rinsed with buffer solution while the cellulase attached to lignin was difficult to be eluted. All three lignin surfaces during cellulase adsorption had good viscoelasticity with little difference. Conclusion: Lignin present an obvious adsorption effect on cellulase, lignin with the same structural units, even from different sources, showed the same adsorption capacity of lignin to cellulase. Different structural units of lignin have different adsorption capacities for cellulase. Cellulase was hard to be removed because of its binding closely on the surface of lignin film. The lignin with higher S/G ratio showed more strong adsorption capacity to cellulase, which produced more ineffective adsorption in cellulase hydrolysis, and led to reduction of glucan conversion efficiency in enzymatic hydrolysis.

The urbanization process and living environment improvement have led to more and more expansion of wildland-urban interface (WUI) areas throughout the world, and most WUIs face severe fire risks. The impact of WUI fires on ecosystem and society has attracted worldwide attention, and fire management in WUI area has become a challenge for current regional development. Over the last 30 years, WUI fire research has become an important research hot topic. WUI fires have also occurred frequently in China in recent years, but there is little research on such fires. This paper systematically introduces the research achievements on WUI fire from three aspects, such as the definition of WUI and its fire regime, fire risk assessment, and risk mitigation measures. Fire risk assessment of WUI area especially emphasizes the exposure and vulnerability of fires, and the fire impact on the environment and society. The risk mitigation strategy needs to be developed based on the fire risk assessment results, which includes reducing the potential fire intensity and exposure of WUI area through fuel management, improving the construction materials and design of houses and other infrastructure, enhancing fire resistance capacity, heightening the fire awareness and fire resistance capacity of residents, and improving the fire fighting ability and comprehensive disaster resistance capacity of the community. The future research trend is to develop WUI fire spread model, smoke transmission and economic loss model, fuel management technology in WUI area, and WUI planning and relevant management standards. It is needed to carry out interdisciplinary and international research. The research achievements will provide reliable fire risk assessment methods and mitigation technologies, which should provide the supports for formulating corresponding management strategy and risk mitigation schemes for WUI areas with different characteristics. China also needs to improve the fire adaptability of WUI community by formulating relevant technical standards and procedures for WUI fire management, and make targeted fire management plans according to reliable fire risk assessment method and mitigation technology.

Bamboo scrimber is a kind of biomass composite material, which is prepared from bamboo fiber mat (as matrix) and resin (as reinforcement). It is one of the effective ways to achieve the efficient and high-valued utilization of bamboo, and has become to main products of bamboo industry in China. The bamboo scrimber performed great physical and mechanical properties, which developed in both applications of indoor and outdoor, including floor, bamboo furniture, cement template, wind-power blades, weather resistance landscape and architecture structural materials. However, the basic scientific issue, key innovative technologies and applied engineering technologies were still need to be studied together. In this study, the technical connotation, cross-response mechanism and manufacturing regulatory mechanism of bamboo unit, heat treatment, resin impregnation, drying and modeling process were classified according to the published reports that discussed and summarized the performance evaluation and functional application of bamboo scrimber. The improvement of product and application techniques was put forward, basing on the analysis of the scientific issues and results of composite, porous materials and biomass materials. Moreover, the upgrade of equipment and the enhancement effect of bamboo scrimber was defined to provide theoretical and technical support of scientific application.