Objective: Based on the spatial distribution data of genus Sapindus in China, the suitable range for distribution and main ecological characteristics of Sapindus were explored to provide the scientific basis for seed allocation, protection of genetic diversity of germplasm resources, introduction and cultivation, site selection of Sapindus. Method: Based on the spatial distribution data of 133 representative accessions of germplasm resources of Sapindus which screened from 226 accessions of germplasm resources by overlay analysis, combined with 24 ecological factors, the maximum entropy model (MaxEnt) was used to establish the relationship model with the ecological factors for the prediction of the potential distribution area of Sapindus. The model uses the receiver operating characteristic curve (ROC curve) to check the accuracy and uses the Jackknife method to screen the dominant ecological factors. The model is combined with the ArcGIS system to realize the visualization of Sapindus potential distribution area in China. Result: Simulation of the MaxEnt model displayed a high credibility, and the AUC values of the training set and test set of the ROC curve of the Sapindus distribution were both above 0.990. The area of the potential distribution of Sapindus is 248.71×10⁴ km², accounting for 25.81% of the total land area of China. S. mukorossi is 240.66×10⁴ km² (24.99%), S. delavayi is 78.99×10⁴ km² (8.20%), and Sapindus rarak is 100.40×10⁴ km² (10.42%). The ecological factors that significantly affected the suitable distribution of S. mukorossi are the precipitation of the warmest quarter (57.1%) and Isothermality (22.6%). The significant ecological factors of S. delavayi are the precipitation of warmest quarter (37.9%), mean temperature of coldest quarter (15.9%), elevation (12.8%), and precipitation seasonality (11.2%). The significant ecological factors of S. rarak are temperature annual range (19.6%), precipitation of warmest quarter (17.8%), oxygen availability to roots (11.9%), and isothermality (11.1%). Conclusion: The potential occurrence area of Sapindus are widely distributed in central and southern China; The highly favorable area of S.mukorossi is mainly distributed in Fujian Povince, Guangxi Zhuang Autonomous Region, Guizhou Province, Chongqing City, northern Guangdong Province, Nanchang, and Ganzhou Cty in Jiangxi Province and Sichuan Basin in Sichuan Province. The highly favorable area of S. delavayi is concentrated in Sichuan Basin in Sichuan Province, Kunming, and Qujing Cty in Yunnan Povince. The highly favorable area of S. rarak is concentrated in Yuxi, Pu'er, Honghe Hani Yi Autonomous Prefecture, Wenshan Zhuang Autonomous Prefecture, and other regions in southern Yunnan Province. The precipitation of the warmest quarter is the most significant ecological factor that determines the potential distribution area of the genus Sapindus and the three species of the genus. S. mukorossi is suitable for the region of precipitation of warmest quarter range from 400 mm to 800 mm, isothermality range from 24% to 35%. Compared to S. mukorossi, S. delavayi is suitable for the region of high elevation (1 200~3 000 m) and moderate mean temperature of coldest quarter (4~11℃). And S. rarak is suitable for the tropical regions where the temperature annual range from 14℃ to 24℃ and the precipitation of warmest quarter range from 550 mm to 1 550 mm.

Objective: Site classification and quality evaluation of Eucalyptus urophylla×E. grandis plantation in hilly and mountainous region in south-central Guangxi was studied to provide scientific basis for the sustainable management of the plantation for raw material production for pulp-making. Method: Using the typical sampling method, 94 sample plots of the plantations aged between 1 and 15 years were set up. The quantification theory Ⅰ was used to analyze the relationship between tree growth and site factors, and hierarchical clustering analysis, descent correspondence analysis and redundancy analysis were applied to classify the sites and evaluate the site quality. Result: The main factors affecting the site quality in south central Guangxi were slope, soil type, soil layer thickness, soil density, slope position and humus thickness in order. Based on the combination of slope, soil type and soil layer thickness, the site was classified into eleven types, and further divided into Ⅰ-Ⅲ site classes according to the height of dominant tree at the baseline age of 6 years. The age at which the stand volume of the three site classes reach quantitative maturity was 9, 8 and 7 years, respectively. Site class I was a high quality site with low slope, latosolic red soil or laterite and thick soil layer. The mean height, mean diameter at breast height (DBH) and mean annual volume at the baseline age of 6 years were 22.6 m, 14.3 cm and 32.09 m³·hm^-2a^-1, respectively. Site class Ⅱ was a site with gentle slope, laterite or red soil and medium soil thickness. The mean height, mean DBH and mean annual volume at the baseline age of 6 years were 19.1 m, 12.7 cm and 21.39 m³·hm^-2a^-1, respectively. Site class Ⅲ was low quality site with incline slope or steep slope, red soil or yellow soil and thin soil layer. The mean height, mean DBH, and mean annual volume at the baseline age of 6 years were 16.7 m, 10.4 cm and 12.54 m³·hm^-2a^-1, respectively. The height and DBH displayed significant positive correlations with soil total N, total K, hydrolytic N, available P, available K, available B, and content of organic matter, but significant negative correlations with pH value and soil density. Conclusion: Attention should be paid to the classification of site types for E. urophylla×E. grandis plantations in hilly and mountainous region in south central Guangxi with the principles of matching species with the sites and scientific forest management. According to different site classes, fertilization based on soil testing and appropriate addition of N, P, K, and B can significantly improve the production potential of forest land.

Objective: The size of twigs and leaves and leafing intensity are closely related to the overall shape of plants. Exploration of the variation of twig and leaf traits in different latitudes can predict the intraspecific variation and survival strategies of plants in different environments. Method: In this study, four different regions in the mixed broadleaved-Korean pine forests were selected to analyze the leafing intensity, cross-sectional area, total leaf area and single leaf area of the main dominant species Pinus koraiensis. The one-way ANOVA was used to test whether there was a significant difference in different latitudes by analyzing twig traits and leaf traits. The standardized major axis (SMA)was used to investigate the effects of latitude on the relationships between volume-based leafing intensity and individual leaf area, and between twig cross sectional area and individual leaf area, total leaf area, volume-based leafing intensity. Result: 1) The latitude explanatory rate of changes in total leaf area, twig cross-sectional area and leafing intensity of P. koraiensis were was all less than 8%, and the latitude explanatory rate of changes in individual leaf area was the highest at 58%. 2) The twig cross-sectional area had an allometric growth with volume-based leafing intensity and other leaf characters, and it had a significant positive correlation with total leaf area and individual leaf area at different latitudes, but a negative correlation with leafing intensity. At high latitudes, allometric growth was negatively correlated with leafing intensity and individual leaf area. 3) At high latitudes, there was a negative relationship between leaf area and leafing intensity. Conclusion: The leaf and twig traits of P. koraiensis are significantly different at different latitudes. With the change of latitude, the individual leaf area changes significantly, indicating that plants can adjust their phenotypic traits to adapt to the changing environment, and leaf traits are mainly changed. The relationship between twig and leaf traits of P. koraiensis varies in different latitudes, and the slope is relatively small in high latitudes, indicating that plants adopt different resource allocation strategies to adapt to environmental changes, and the leaf and twig traits adapt to environmental changes cooperatively.

Objective: This paper aims to determine the high temperature and drought index and its influence relationship in the key growth period of Camellia oleifera by investigating the influence of meteorological factors on the yield of C. oleifera, so as to early warn the high temperature and drought disaster of C. oleifera. Method: In this study, the standardized yield data of C. oleifera in different regions of Hunan Province and the meteorological data from 2007 to 2015 were collected. The data included the average temperature, precipitation, sunshine hours, days of precipitation and days of heat accumulation temperature ≥ 30℃ and high temperature ≥ 30℃ in the fruit expansion period and oil conversion period of C.oleifera. A regression analysis was carried out with the standardized yield of C. oleifera and the meteorological data to determine the factors and thresholds that could indicate the occurrence of drought, and to establish a yield prediction model. Result: At the fruit expansion stage, there was a significantly negative correlation in between the precipitation days and the standardized yield of C. oleifera. In the fruit expansion stage and the oil conversion stage, the heat accumulation temperature ≥ 30℃ and the days of high temperature ≥ 30℃ were significantly negatively correlated with the standardized yield of C. oleifera. The threshold values of high temperature and drought were when the accumulated temperature of ≥ 30℃ reached 36.7℃ or the high temperature ≥ 30℃ lasted for 26 days in the fruit expansion stage, and the accumulated temperature of ≥ 30℃ reached 13.6℃ or the high temperature ≥ 30℃lasted for 10 days in the oil conversion stage. The results showed that the model with daily accumulated temperature ≥ 30℃ in fruit expansion stage was the best for predicting standardized yield of C. oleifera. Conclusion: The threshold values of accumulated temperature or high temperature days in fruit expansion period and oil conversion period, which would lead to high temperature and drought disaster, can be used as early warning signal for yield reduction of C. oleifera. In this study we also put forward the measures for disaster prevention and mitigation. The heat accumulation temperature ≥ 30℃ and the days of high temperature ≥ 30℃ are the key factors from fruit expansion stage to oil conversion stage of C. oleifera, based on which a model for predicting the yield of C. oleifera is established, and it can better predict the yield of C. oleifera in medium and short term. This study provides reference for management decision-making of C. oleifera.

Objective: At present, the evaluation system for human life and health has been very mature, but there is no scientifical and mature evaluation standard for plant life. In this article, we intend to construct a model that can reflect the growth status of plants by analyzing the stem moisture information collected by the stem moisture sensor of living standing trees, and to provide a model basis and solution ideas for building a assessment system of plant life status in the future. Method: The stem moisture data of poplars were collected from 2017 to 2018.The annual plant growth status was divided into: germination stage, growth stage, defoliation stage, and dormancy period, and the moisture content of plant stems at each stage was analyzed. Then, the principal component analysis of multi-dimensional environmental data was carried out, and the maxmum principal component PC1 and the stem moisture data of the standing trees were selected for further analysis. Anellipse model of plant stem water moisture was proposed to evaluate the status of plant vital signs. Result: In the germination stage, the stem moisture content of poplars increased. The average daily value was 20% at the beginning of April, and increased to 43% at the end of April. The daily variation amplitude was 5%-8%.The daily average value of stem water in July was stable at 50%.The change was affected by the weather, and the differencein daily variation was obvious, with a maximum of 9% and a minimum of 1%.The stem moisture decreased gradually from the average value of 46.9% at the beginning of October to 42.8% at the end of the month, and the daily variation amplitude decreased to 4%.During the dormant period, the water freezed and thawed due to low temperature, and the stem moisture fluctuated drastically. The minimum value in December was 12%, the maximum value was 42%, and the daily variation amplitude was up to 20%. An elliptic curve was fitted for different growth stages of plants. The fitting results showed that the change pattern of stem water in spring germination period and winter dormancy period was similar, and the elliptical inclination is < 0°, which was negatively correlated with PC1 changes. The changes of stem moisture in summer growth period and autumn defoliation period were similar, which was positively correlated with PC1 changes. Among them, the plants in the growing period were less affected by the environment, and the absolute value of the elliptical inclination was the smallest. The inclination and rotation direction can be used to infer the lead-lag relationship between stem moisture and environmental parameters. The stem moisture in the germination and dormancy periods lagged behind the environmental parameters, and the stem moisture in the growing and defoliating stages was ahead of the environmental parameters. Conclusion: The stem water content-based growth state assessment proposed in this paper provides a new research direction for the research of plant vital signs. The four-stage ellipse fitting curve has higher discrimination, which can be used as a criterion for plant growth status. Based on this, a more perfect plant physiological evaluation system can be further studied and applied to actual production and life.

Objective: Tree peony (Paeonia suffruticosa) has a short and concentrated florescence, in order to explore the mechanism of autumn flowering, we studied the effects of gibberellin and DNA methylation during autumn flowering of tree peony. Method: Before natural defoliation in the middle September, all plants of the variety (P. suffruticosa 'Togawakan', a spring and autumn flowering variety of tree peony planted in the open field in Luoyang, Henan Province) were divided into 4 treatment groups: defoliation, defoliation + 650 mg·L^-1 gibberellin (GA₃), defoliation + 500 mg·L^-1 paclobutrazol (PP₃₃₃) processing, and no treatment. Growth performance of the treatment groups and the control was observed and recorded during autumn bud germination and flowering process, and the physiological and biochemical processes and methylation of genomic DNA of the treatment groups were measured. Result: 1) All of the four treatment groups could naturally flower in the autumn, but applying the treatments could promote 'Togawakan' autumn secondary flowering in advance and increase the effect of the flowering uniformity. Particularly, the treatment group of defoliation + 650 mg·L^-1 GA₃ had the best effect on promoting 'Togawakan' to sprout and flower, with a sprouting rate of 81.4%, 11 days after the treatment, and initial flowering started 42 days after treatment, 30 days earlier than the control group. 2) The defoliation + 650 mg·L^-1 GA₃, defoliation and defoliation + 500 mg·L^-1 PP₃₃₃ all contributed to fast and neat sprout and growth of the variety 'Togawakan', and the acceleration of flowering decreased in turn, suggesting that defoliation could promote sprout and growth of the buds, applying GA₃ has superposition promoting effect, PP₃₃₃ could offset the promoting effect of defoliation to a certain degree. Defoliation exerted an inhibitory effect on GA₃ and GA₄ content for a short time at first, then followed by an increase of GA₃ and GA₄ contents, and a decrease of ABA content in buds. The application of GA₃ enhanced the intensity of increased GA₃ and GA₄ contents and decreased ABA content, and prolonged the rising period of GA₃ and GA₄ contents, while the application of PP₃₃₃ showed the opposite effect. 3) Sprouting and flowering were accompanied by the consumption of a large amount of starch and soluble sugars, and a high concentration of soluble sugar may be beneficial to flowering. 4) MSAP test showed that the variation range of total DNA methylation in 'Togawakan' during the whole experiment period was 57.3%-72.4%, reaching the highest level of total DNA methylation before sprouting, and followed by a gradual decrease. The methylation of the control 1 day after treatments, as the baseline was compared with those of the treatment groups in different treatment periods. It was found that the methylation in treatment groups was more actively changing, and the changes were concentrated in two models, demethylation and hypermethylation. The demethylation rate of each treatment group increased with time and was higher than that of the control group in the same period. It was speculated that the high demethylation rate may be more conducive to the bursting of 'Togawakan' in autumn. Conclusion: P. suffruticosa 'Togawakan' could naturally sprout and flower in autumn, defoliation promoted endogenous GA₃ synthesis, combined with the superposition effect of exogenous GA₃, increased GA₃ and inhibited ABA in vivo, promoted its secondary flowering in autumn, and the flowering period was neat. Exogenous PP₃₃₃ application to some extents counteract the synthesis of endogenous GA₃ caused by defoliation. Sprouting to flowering was accompanied by a large amount of sugar consumption, high concentration of soluble sugar might be conducive to bud sprouting. 'Togawakan' can self-regulate the methylation status at locus CG of relevant DNA sequences, thus inducing flower buds to sprout in autumn, and application of the treatments could trigger this regulation process ahead of time, in which high DNA demethylation rate was more likely to promote autumn germination and flowering.

Objective: In order to provide a basis for advanced-cycle genetic improvement and sustainable utilization of Larix kaempferi, genetic diversity and its variation trend of the introduced provenance population(IP), the first cycle breeding population(FP) and the second cycle breeding population(SP) of L. kaempferi in northern subtropical subalpine region were compared and evaluated using EST-SSR markers. Method: 16 SSR markers were used to analyze the genetic diversity of 873 individuals from three populations of L. kaempferi. Estimation of genetic diversity parameters, analysis of molecular variance(AMOVA) and principal coordinate analysis(PCoA) were carried out using GenAlex 6.41. Result: A total of 106 alleles were detected at 16 pairs of primers in all the samples with an average of 6.7 alleles. The polymorphism of different loci was significantly different, among which 14 loci were moderately to highly polymorphic, indicating that these markers could well reflect the genetic diversity level of the population. The average effective allele number (N_e), Shannon diversity index (I) and polymorphism information content (PIC) of the three populations were 2.543, 0.979, and 0.480, respectively, indicating that all of the three populations had high level of genetic diversity. The diversity index I of IP, FP and SP were 0.911, 1.017 and 1.009, and the PIC were 0.432, 0.484 and 0.488, respectively. These indicated that the genetic diversity parameters of FP and SP were slightly higher than those of IP and there was no significant difference among the three groups. In general, the genetic distances among three populations were small, ranging from 0.006 to 0.075. The genetic distance between IP and FP was higher than that between IP and SP, while the genetic distance between FP and SP was the least. AMOVA analysis also showed that the differentiation among the three populations was small, and the variation mainly came from within the populations. Allele frequency comparison and PCoA analysis showed that the genetic basis of IP was obviously different from that of the other two populations. The genetic diversity level of SP could be effectively improved by introducing a small number of genotype with large differences from SP in IP. Conclusion: The genetic diversity of L. kaempferi breeding populations in northern subtropical region were high and the level of genetic diversity of improved population did not decrease compared with the introduced introduced provenance population. It was suggested that current breeding strategies in the region were appropriate for maintaining genetic diversity. The differences of origins among the three populations, pollen contamination in breeding process and high intensity of directional selection were the main causes for the differences in genetic composition and genetic diversity between the introduced provenance population and the first and the second cycle breeding populations. Replenishing the original resources into the breeding population in time is particularly important for the construction of advanced-cycle breeding populations of exotic species like L. kaempferi.

Objective: NUCLEAR FACTOR Y(NF-Y) is a ubiquitous transcription factor in eukaryotes. It consists of three subunits, NF-YA, NF-YB and NF-YC, all of which can form heterotrimer to regulate the expression of downstream genes by binding to cis-acting elements of CCAAT in the promoter region, thus participating in plant development and abiotic stress response. In this study, the expression characteristics and functional analysis of the PwNF-YB8 gene in Picea wilsonii were analyzed in order to reveal the physiological processes involved and the responses to abiotic stress. Method: According to the sequences of P. wilsonii NF-Ys family genes obtained from the pre-laboratory EST sequencing and RNA-seq transcriptome database, the cDNA sequence of PwNF-YB8 was cloned and its encoded protein was analyzed by sequence characteristics and evolutionary tree. qRT-PCR was used to analyze the expression characteristics of PwNF-YB8 in different tissues and pollen germination process, as well as the expression changes under heat, NaCl stress, mannitol treatment, ABA treatment. Subcellular localization revealed where PwNF-YB8 worked in cells. The transcriptional activation activity of PwNF-YB8 and its interaction with PwHAP5(NF-YC subunit) were detected by yeast two-hybrid assay and bimolecular fluorescence complementation assay, respectively. The Arabidopsis Col-0(WT) was transferred by floral dip method to obtain homozygous PwNF-YB8 overexpressing lines. Mutants of its homologous gene AtNF-YB8 were obtained by using CRISPR/Cas 9 technology. The germination rate and seedling root length of wild type (WT), empty vector (VC), mutant lines (nfyb8-cas9#1/12) and overexpression lines (L4, L5) were measured under mannitol and NaCl treatment, and the tolerance of different lines to osmotic stress and salt stress was analyzed and compared. Result: The open reading frame of PwNF-YB8 gene is 489 bp, which encodes 162 amino acids, has a typical NF-YB conserved domain, and has a close relationship with the homologous genes of Picea glauca. The SqRT-PCR and qRT-PCR both showed that PwNF-YB8 was expressed in roots, stems, needles and pollen of P. wilsonii, with the highest expression in pollen. Subcellular localization showed that PwNF-YB8 was localized in the nucleus and cytoplasm. Yeast two-hybrid assay showed that PwNF-YB8 had no transcriptional activation activity. After further treatments of the seedlings of P. wilsonii with heat (42℃), NaCl stress, mannitol and ABA, it was found that PwNF-YB8 responded significantly to abiotic stresses such as drought and salt. PwNF-YB8 participates in the pollen germination process, and its expression is the highest at 36 h of pollen germination. The yeast two-hybrid experiment and bimolecular fluorescent complementary experiment proved that PwNF-YB8 can interact with PwHAP5, and may participate in the regulation of pollen tube development. Under mannitol or salt treatment, the seed germination rate of Arabidopsis overexpressing the PwNF-YB8 gene was not significantly different from that of the wild type, but its root length showed a certain growth advantage. Conclusion: Picea wilsonii PwNF-YB8 gene can interact with PwHAP5, participate in pollen germination and pollen tube growth, and play a role in response to drought and salt stress.

Objective: Species abundance distribution of community is the base for the biodiversity and community assemblage rules. Aim of the study was to fit the species abundance distribution of spruce-fir broad-leaved tree species mixed forest in overcutting forest zone in northeast of China and to interpret the ecological mechanisms behind the pattern. Method: Empirical statistical model, niche model, unified neutral theory model and niche composite model were used to analyze the species abundance data from the 12 communities of spruce-fir broad-leaved tree species mixed forest in overcutting forest zone in northeast of China. Result: 1) Logarithm normal distribution(ln)model and Poisson logarithm normal distribution(pl)model performed better than the logarithm series model(ls), the T parameter from the ls model and the λ parameter from the ln model characterized the biodiversity property of the 12 communities. 2) Among the 7 niche models, the random broken sticks model performed the best, followed by the overlapping niche model, geometrical series model, Zipf model and Zipf-Mandelbrot model, and the random assortment model and the dominance preemption model performed the worst. 3) The fitting capacity of the composite model performed better than the other traditional niche models listed above, especially when the abundances of common and rare species were in different competition hierarchies; the empirical model and the niche model exhibited the same performance when the basal area were used as generalized abundance indices, while the composite model and the unified neutral model had differences with that for individual number as abundance indices. Conclusion: Composite model was a combination of two simple niche model, it could span the bridge between empirical model, niche model and neutral theory model, and open up new ways for the species abundance pattern analysis. The species abundance of spruce-fir broad-leaved tree species mixed forest in overcutting forest zone in northeast of China was a combination of deterministic and stochastic ecological processes, and represented multiple mechanisms such as seed source dispersal, interspecific competition, forest cutting and random disturbance, overlogged forest community was in the stage of recovery succession, niche process may dominate.

Objective: The crown of a tree is an important organ for material exchange and energy conversion. The nonlinear mixed effect model and the nonlinear quantile regression model of the maximum crown outline were constructed to provide a scientific basis for accurately predicting the growth and development law of the crown and its productivity. Method: Taking Larix principis-rupprechtii plantation of Saihanba forest farm in Hebei Province as the research object, based on 1 789 branches data of 58 trees, the power equation, modified Kozak and modified Weibull equation were selected as the basic models to construct a mixed effect model and a nonlinear quantile regression model for predicting the crown shape of L. principis-rupprechtii plantation. Result: Among the power function, modified Kozak equation and modified Weibull equation, the power function equation had the best fitting effect of tree crown profile. The power function equation was chosen as the basic model of tree crown profile. Stand age (Age), diameter at breast height(DBH), height of the tree (HT), crown height ratio (CHR), and height to diameter ratio (HDR) had significant effects on fitting crown contour. In the mixed effect model, the two-level mixed effect model considering both plot and tree effects was superior to the single-level mixed effect model. The random effect of the plot was added to the HDR parameter, and the random effect of the sample was added to the RDINC(relative depth into crown) and CHR parameters. The model determination coefficient (R²) was 0.873, the root mean square error (RMSE) was 0.319 m, and the mean relative error (MRE) was 6.642 m. In the quantile regression model, when q=0.90, the model curve model was the closest to the crown maximum profile, R² was 0.672. Conclusion: The mixed-effect model might be a better fitting accuracy and could accurately describe the average trend of the largest branches of the canopy. The quantile regression model could determine the outermost contour of the canopy and may play an important role in research beyond the prediction of conditioned mean.

Objective: Forest stands are the basic units for forest resources monitoring and management. Using remote sensing data to accurately classify forest stand types has always been a hot topic in forestry research. The paper aims to explore the influence of classifiers and data sources (hyperspectral data and LiDAR data) on forest type identification, and to test whether chlorophyll plays an positive role in the identification. Method: This study area is at Laoshan working unit of Mao'ershan forest farm of Northeast Forestry University, and the airborne hyperspectral image and LiDAR point cloud were used as experimental data sources. Based on multi-scale image segmentation, spectral, texture and chlorophyll index features were extracted from hyperspectral images, and height and intensity features were extracted from LiDAR point clouds. Through the feature selection method of RF, features with higher importance were selected. Based on the classifier of RF and SVM, the image segmentation data were used as experimental samples to identify five forest types: broad-leaved mixed forest, Pinus sylvestris var. mongolica forest, Larix gmelinii forest, Pinus koraiensis forest and Quercus mongolica forest, and the classification effects of different data sources and different classifiers were compared. Result: A total of 34 feature variables were extracted from hyperspectral data, and 72 feature variables were extracted from LiDAR data. After feature selection, 11 feature variables were selected from hyperspectral data and LiDAR data, respectively, and normalized differential vegetation index(NDVI) extracted from hyperspectral data was the most important variable among them. Among the six classification schemes, the highest classification accuracy was to used hyperspectral and LiDAR data and RF classifier (overall accuracy was 88.02%), and the lowest classification accuracy was to use LiDAR data and SVM classifier (overall accuracy was 76.19%). The average classification accuracy of multi-source data was 86.22%, which was higher than the average classification accuracy of single data source of 79.98%. The average classification accuracy of RF classifier was 82.92%, which was higher than that of SVM (81.19%). At the same time, the results indicated that the chlorophyll index had a positive impact on stand type identification, and the classification accuracy had improved by about 3.32% after participating in classification. Among the five stand types, the broad-leaved mixed forest had the best classification effect with an average classification accuracy of 92.62%, while the Korean pine forest had the worst classification effect with an average classification accuracy of 49.67%. Conclusion: Compared with single data source, multiple data sources could better improve the accuracy of stand type identification. When using single data source, hyperspectral data had better classification effect than LiDAR data, and spectral characteristics were important factors that influenced stand type identification. In the process of stand type identification, comparing different machine learning models, RF had better classification effect than SVM. Additionally, as a biochemical parameter, chlorophyll had a positive effect on stand identification.

Objective: Presently, during the diameter at breast height(DBH)measuring process of nation continuous forest inventory, there are some shortages such as poor applicability, complex operation and low efficiency, and calipers are poor portability and short range. In order to solve the actual work needs of forestry surveyors, an efficient, accurate, portable tree DBH measurement device with integrated automatic reading, recording and uploading functions was expected to be designed. Method: A new DBH measurement method and device based on three-segment arms and two angle sensors was designed in this study, and the effectiveness of the device had also been evaluated in experiments. Result: 1) The results showed that 200 measurements of 15 cylinders had a 0.19 cm(0.79%)mean absolute deviation(MAE)and a 0.25 cm(0.94%)root mean square error(RMSE). 2) The results showed that measuring 218 trees of different diameter classes had a 0.22 cm(0.89%)mean absolute deviation(MAE)and a 0.42 cm(1.23%)root mean square error(RMSE). 3) The average measuring time of each tree was 8.67 s from the efficiency test in a 83-tree sample plot. Conclusion: The device developed by this paper may be advantageous to simple mechanical and electrical structure, suitable for big tree measurement, foldable design, convenient to carry and keep, simple operation and high efficiency, and be more suitable for measurement of large trees and realized the integration of measuring, uploading and inputting of DBH data, which would be accorded with the survey accuracy standard of continuous forest inventory.

Objective: This study aims to clarify the invasion, colonization, and severe damage of the major international forest quarantine pest Hylurgus ligniperda in China. The morphological characteristics, molecular identification, and damage characteristics were studied, so as to provide a theoretical basis for the monitoring and control of this pest. Method: The morphological characteristics of the larvae, pupae, and adults H. ligniperda collected from the roots of Pinus thunbergii in Muping District, Yantai City, Shandong Province were observed, photographed, and compared. The genomic DNA was extracted, and the sequences of the large ribosomal subunit 28S and mitochondrial cytochrome oxidase subunit Ⅰ(COⅠ) were amplified and sequenced using general primers of the subfamily. The sequences were compared with the existing sequences in the NCBI database. The damage characteristics of H. ligniperda were preliminarily investigated. Result: The morphological characteristics of the adults were completely consistent with the description of H. ligniperda. The phylogenetic tree (ML tree) based on the 28S gene sequences showed that the samples from Yantai Shandong, Xiamen Port intercepted samples from Australian Radiata Pine logs, the German samples, and the American samples were clustered into one branch with 100% confidence. The Yantai Shangdong samples shared the same haplotype with the H. ligniperda samples intercepted from New Zealand Radiata Pine logs based on COⅠ sequence, indicating that the invasive alien species H. ligniperda has been established in China. This insect seriously damages roots of the host trees. Conclusion: It is the first time to find the colonization and serious damage of the major invasive pest, H. ligniperda, in China. The main morphological characteristics have been identified, and the infestation characteristics have been preliminarily clarified. The results of gene sequence analysis provide a basis for developing rapid identification technology and traceability analysis. This study would provide a theoretical basis and technical support for its detection and monitoring.

Objective: This study aims to find a suitable bioindicator of chemotaxonomic characters reflecting the developmental stage of the larvae of Yunnan shoot borer Tomicus yunnanensis (Coleoptera: Curculionoidea: Scolytidae) in order to further improve the comprehensive ability of scientifically integrated management on the insect pest and the forecasting accuracy. Method: The instar numbers were determined based on morphological indexes, including head capsule width, body length, maxilla length and width. Cuticular hydrocarbons were extracted by immersing larval individuals of different instar numbers in the pure n-hexane. The hydrocarbon extracts were analyzed by using gas chromatograph mass spectroscopy (GC-MS). The kinds and contents of compounds were determined by matching MS library and confirmed by comparison of Kovat's index (KI) and C8-C40 alkane mixture standards. The principal component analysis and random forest analysis were used to analyze the chemical composition and compare the changes of the composition of cuticular blends among age classes. The content among the larval instars was also compared by Kruskal-Wallis test. Result: The cuticular hydrocarbons of T. yunnanensis larvae were composed of nineteen compounds that contained n-alkanes, branched alkanes and alkenes. Their amounts are orderly dominated by N-pentadecane was the representative of n-alkanes, accounting for 55.02%±8.20%, the content of 13-methyl-docosecane accounted for 94.04%±14.02% of the total branched alkanes, the highest, and the main alkenes were 1, 21-docosadiene, accounting for 63.03%±0.39%. With the development of larval instars, both length and kind of carbon chains increased significantly. The content increased exponentially (y=e^{0.086 5x-0.629}, R=0.911). There were 8 kinds of hydrocarbon components in the 1^st instar larvae, and the content was (2.32±0.59) ng·ind^-1. There were 8 hydrocarbon components in the 2^nd instar larvae, and the content was (44.40±11.46) ng·ind^-1. There were 17 hydrocarbon components in the 3^rd instar larvae, and the content was (280.75±72.48) ng·ind^-1. The combined contribution rate of the first principal component and the second principal component was 81.7%, which could distinguish the larva of different instar numbers of T. Yunnanensis. There was non-overlap between the instar classes, indicating that the classification standard was obviously better than the morphological index method. The 2, 6, 11-trimethyl-dodecane, n-pentadecane, n-nonadecane, n-tricosane and n-pentadecane were relatively important in the given variables, and their contents were significantly different among larval instars (P < 0.000 1). Among them, 2, 6, 11-trimethyl-dodecane could be regarded as an existential candidate for the 1^st instar larvae, n-tricosane and n-pentacosane could be used as a predicated criterion for the 2^nd and 3^rd instar larvae, respectively. Conclusion: The kinds and contents of the cuticular hydrocarbons in different larval instars of T. yunnanensis are significantly different. The 2, 6, 11-trimethyl-dodecane can be used for identification of the 1^st instar larvae, n-tricosane and n-pentacosane can be used to identify the 2^nd and 3^rd instar larvae, respectively. Our results indicate that the cuticular hydrocarbon of T. yunnanensis larvae is an optimal index for the taxonomic identification of instar numbers.

In this paper, a new species, Megaxyela leucostigma sp. nov., of the genus Megaxyela from Tianmu Mountain, Zhejiang Province, China, is described and it is possibly a new pest of Carya cathayensis. The new species obviously differs from the known species of the same genus by the wings entirely hyaline with milky white pterostigma and veins as well as the apical ovipositor sheath yellowish white. M. leucostigma is sympatric with M. euchroma Blank, Shinohara & Wei, 2017 and they may have the same host of Carya cathayensis of Juglandaceae, but the new species differs from M. euchroma by the narrow apical sheath. The K2P distance between the COⅠ of M. leucostigma and M. euchroma is 10.85%, which is similar to the interspecific distance of other species of the same genus (7.6%-13.5%). A key to Asian species of the genus Megaxyela is provided.

Objective: To understand the difference in mechanical properties of juvenile woods among Chinese fir clones, a serial of standard wood samples were prepared by two new-certificated clones in a 10-year-old growth performance demonstration plantation to analyze the microstructure characteristics of juvenile woods. Method: The microstructure and mechanical properties of juvenile woods of Chinese fir clones were analyzed by microscopic image analysis system, X-ray diffraction technique, Fourier transform-infrared microscopic imaging and the national standards of mechanical properties testing. The data of microstructures were observed from 'Yang 020' and 'Yang 061', involving the anatomical structure, microfibril angle, crystallinity and chemical composition lignin, as well as main mechanical properties such as modulus of rupture (MOR), modulus of elasticity (MOE) and compressive strength parallel to grain and hardness, and were processed by one-way variance analysis. Result: The tracheid morphology of earlywood was similar between 'Yang 020' and 'Yang 061', however, there was a significant difference on latewood tracheid morphology. In comparison with colne 'Yang 061', clone 'Yang 020' presented with wider latewood zone, thicker tracheid wall, smaller tracheid lumen and a 25% larger wall-lumen ratio. At the aspect of cell walls, the average microfibril angle for 'Yang 020'and 'Yang 061' was 12.06° and 14.97°, respectively, indicating that a smaller microfibril angle would have more fine mechanical properties for 'Yang 020'. The average crystallinity for 'Yang 061' was 35.88%, about 11% lower than 39.73% for 'Yang 020'. The average lignin content, presented by four groups of characteristic peak ratios on 'Yang 020' was 8% higher than that on 'Yang 061'. The average MOR, MOE, compressive strength parallel to wood grain and wood hardness of 'Yang 020' vs 'Yang 061' was 51.36 MPa vs 42.56 MPa, 10.18 GPa vs 8.98 GPa, 30.27 MPa vs 27.20 MPa and 1 497 N vs 1 391 N, respectively. Each mechanical property indicator, such as MOR, MOE, compressive strength parallel to wood grain, and wood hardness, of 'Yang 020' was higher than that of'Yang 061' by 21%, 13%, 11% and 8% respectively, indicating that clone 'Yang 020' had better mechanical properties, in a wider latewood zones, thicker tracheid wall, larger wall-lumen ratio, smaller microfiber angle and higher lignin content, while 'Yang 061' had lower mechanical properties, in a narrower latewood zones, thinner tracheid wall, smaller wall-lumen ratio, larger microfiber angle and lower lignin content. Conclusion: For juvenile woods properties of 'Yang 061' and 'Yang 020', there were significant differences between the two clones in microstructures, such as anatomical structure parameters, microfibril angle and lignin content, except for the crystallinity. Clone'Yang 020'had higher tested values on juvenile wood mechanical properties over clone 'Yang 061', with higher bending, compression resistance and hardness. The juvenile wood mechanical properties of Chinese fir clones were positively correlated with anatomical structure parameters, such as tracheid wall thickness and wall-lumen ratio and chemical composition lignin content, while a negative correlation was shown between microfibril angle of cell wall cellulose and mechanical property. The juvenile wood mechanical properties of Chinese fir clones were synergically influenced by the above-tested factors, and it was suggested that the anatomical structure parameters and microfibril angle among them might be the most important impact factors on the juvenile wood mechanical properties of Chinese fir clones.

Objective: The hygroscopicity and swelling behavior of Catalpa bungei earlywood, latewood and the growth ring was real-timely and synchronously documented. This work aimed to reveal the coupling and interaction between the swelling behavior of the earlywood and latewood in individual growth ring. Method: Dynamic vapor sorption analysis with Dino X Lite Digital Microscope(DVS Resolution)was used to determine the separated earlywood(EW), separated latewood(LW), combined earlywood(ELW-E), combined latewood(ELW-L)and the growth ring(ELW)of C. bungei heartwood in individual growth ring. The measurements were taken at a constant temperature of (25±0.1)℃, starting at 0% relative humidity(RH)and increasing in increments of 10% RH up to 90% RH. The each RH process was divided into the water vapor sorption period and equilibrium moisture content(EMC)constant period. During the water vapor sorption period, radial and tangential swelling strain and the sorption isotherm were synchronously measured. During the EMC constant period, whether there was hysteresis between "the swelling behavior" and "EMC" or not was investigated. Result: 1) LW exhibited a slightly higher EMC than EW at the range of 0%-90% RH. As the RH increased, the difference between EW and LW increased at first and then decreased. The reproducibility of latewood samples was better than that of the earlywood samples. 2) In the radial direction, the LW shown a higher swelling strain than EW, and ELW-L was also higher than ELW-E. The growth ring was between the earlywood and latewood. The difference of earlywood and latewood radial swelling strain increased with the increasing of RH. 3) In the tangential direction, the EW showed obviously the lowest swelling strain. However, ELW-E exhibited a similar situation as the ELW, ELW-L and LW. 4) The ratio of tangential to radial swelling for ELW, ELW-L and LW were all about 1.30. At RH above 40%, ratio of tangential to radial swelling for ELW-E and EW suddenly increased, and finally reached 2.28 and 1.83, respectively. 5) Compared with those at 'the water vapor sorption period', the radial and tangential swelling strain of ELW, EW and LW at 'the EMC constant period' were less four orders in magnitude. Conclusion: At any RH during the moisture sorption, the EMC of C. bungei earlywood was less than that of the latewood. The radial swelling of C. bungei growth ring was determined by the net effect of earlywood and latewood, and that of the latewood was dominant. Moreover, the tangential swelling of C. bungei growth ring might be also dominated by the latewood. The ratio of tangential to radial swelling for earlywood was higher than that of the latewood. 'EMC' and 'the equilibrium of radial and tangential swelling strain' of the growth ring, earlywood and latewood were changed synchronously, indicating that there may be no hysteresis between 'the swelling behavior' and 'EMC'.

Objective: This study was designed to analyze afforestation potential of the areas where implements the Three-North Shelter-belt Forest Program (TNSP). Potential areas available for afforestation and their spatial distribution will be obtained, aiming to provide a theoretical basis for building green "Belt and Road", ecological protection in the Three-North Region and the construction of shelter-belt forests consistent with local conditions. Method: A suitability evaluation model was established with 5 indicators, including soil type, land use type, aridity, altitude and slope degree. Indicator's threshold was determined based on conditions required for tree growth and divided by limit condition method. Arc-Gis Analyst Tools were applied to evaluate the afforestation potential with every single indicators, and the spatial distribution of potential areas available for afforestation. Based on the single indicators assessments, an integrated assessment was carried out to obtain future afforestation potential. Meanwhile, the maximum entropy model was applied to predict areas suitable for afforestation in the region of implementing TNSP, which will be compared with the integrated assessment. Result: The single-factor assessments showed that the maximum limiting factor was the aridity. According to the integrated assessment, the area suitable for afforestation may reach 584 600 km², accounting for 17.52% of the total land area. The afforestation area will be concentrated in the northwest, east and southeast of the TNSP region. The accuracy of the maximum entropy model is higher than 0.8, at a good level. It shows that the probability of being suitable afforestation area is mostly contributed by Land Use Type. By removing the existing forests from the model assessment, the area suitable for future arbor forests is 1 109 400 km² while the area for shrub forests is 1 441 100 km², covering 33.24% and 43.19% of the total area of TNSP, respectively. Conclusion: The suitable afforestation area is concentrated in the Tianshan, Altay Mountains and the Junggar Basin in the northwest, and the area to the east of the Inner Mongolia and Ordos Plateau. The distribution pattern of suitable afforestation area on the edge of basin is strip-shaped by topography and the melting snow and ice. Affected by the farmland and pasture, the suitable afforestation area is fragmented in the east and south. Overall, the distribution of suitable afforestation area is mainly affected by agriculture and pasture in the east, by the aridity in the central and by aridity and altitudes in the west.

Objective: Based on the investigation of Trema levigata broom in Xinping county, Yuxi city, Yunnan province, this study aimed to understand the occurrence and damage degree of the disease, and further determine the pathogens and their classification status by molecular biological method. Method: The incidence of the disease was obtained by general survey method, and its damage degree was evaluated. The total DNA of the affected plants was extracted, and the 16S rDNA sequences were amplified by using nested-PCR from the total DNA with phytoplasma universal primer pair P1/P7 and R16F2n/R16R2, then the amplified fragments were cloned and sequenced. A sequence analysis was performed with iPhyClassifier, an online classification and identification tool of phytoplasma, and a phylogenetic tree based on the 16S rDNA sequence was constructed by using Megax software to determine the pathogens and their classification status. The homology of related sequences were compared by online analysis software MUSCLE. Result: The survey result indicated that T. levigata witches' broom approximately occurred in east longitude 101°35'-101°53' and north latitude 23°56'-24°20'. It was mainly in the dry-hot valley region at the low altitudes from 600 to 400 m with relatively high temperature, which also showed that high temperature was conducive to the occurrence of phytoplasma disease. In this region, the disease occurred for three consecutive years. The average incidence rate was 38.9% with moderate damage in July 2018. The 1 246 bp 16S rDNA sequence of T. levigata witches' broom phytoplasma was amplified by PCR amplification (strain: TLWBYN0, GenBank accession: MN513329). Analysis showed that TLWBYN01 shared 99.8% similarity with the reference strain of Candidatus Phytoplasma asteris (GenBank accession: M30790), thus the phytoplasma under study was a 'Candidatus Phytoplasma asteris' related strain and belonged to a member of 16S rI group. The virtual RFLP pattern derived from the F2nR2 fragment of TLWBYN01 was most similar to the reference pattern of the 16SrⅠ, subgroup X (GenBank accession: JF781308), with a pattern similarity coefficient of 0.98. The enzymatic profiling of 17 restriction enzymes showed that only MseI was different from the 16S rI-X reference strain. Thus, the phytoplasma was a variant of 16S rI-X. TLWBYN01 had 99.2% and 99.6% homology respectively with phytoplasma of papaya bunchy top (JF781308) and lagenaria siceraria yellow little leaf (LT594117、LT594118), two members of 16S rI-X subgroup. Conclusion: Trema levigata witches' broom from Xinping county of Yuxi city is a local common disease with moderate damage. But once being infected, the plant growth could be seriously affected. T. levigata witches' broom phytoplasma belongs to the member of 16S rI group and is a variant of 16S rI-X subgroup with being less reported so far, and T. levigata is a new host of phytoplasma. These findings are of great significance for further study of phytoplasma. At the same time the plant is the pioneer tree species for greening and widely distributed, thus the investigation and study on the disease could provide a basis for prevention and control of forest diseases in this region.

Objective: Populations of passerine birds that migrate for long distances are decreasing continuously. In recent years, the declining trend of the population number of Rustic Bunting (Emberiza rustica) is more prominent. Through the long-term monitoring and migration dynamics analysis of the Rustic Bunting population, we intent to provide a scientific basis for the species conservation. Method: From 2001 to 2017, 70 pieces of sticky net with 3 m high and 20 m long were set up in different habitats from 15^th March to 31^th May and from 15^th August to 20^th November in Gaofeng forest region, Nenjiang, China. Patrol was implemented once every half an hour. The birds trapped in the net were recorded and then released after banding. Meteorological data were recorded daily from 2001 to 2017 by Nenjiang meteorological station which located 6 km away from Gaofeng forest region, and downloaded from the website of China meteorological data sharing service. Data were analyzed by SPSS 22.0 software. Result: From 2001 to 2017, a total of 18 155 Rustic Buntings were recorded and banded, including 6 756 Rustic Buntings in spring and 11 399 in autumn. The quantity of banding records fluctuated greatly annually, showing a rapid downward trend in general. The spring migration peak of Rustic Bunting was from 1^st to 20^th April, while the autumn migration peak was from late September to early October, and the ratio of adult to juvenile was 25.4:74.6 and 43.3:56.7 respectively in autumn and in the following spring. The overwintering loss rate of young birds was as high as 41.3% compared with that of adult birds. The correlation analysis between the quantity of bandings and meteorological factors showed that the maximum wind speed and wind direction were the main factors that dominated the migration direction and migration timing of Rustic Bunting. Recapture indicated that Northeast China is an important and relatively stable migration corridor for Rustic Bunting and other birds. Conclusion: In recent years, the population of Rustic Bunting has decreased sharply. The number of the birds banded decreased by more than 90% compared with the year with the largest number of banding, which is worthy of attention. Abuse of pesticides, surface water pollution, habitat fragmentation and illegal hunting are the main threats to the survival of Rustic Bunting. It is suggested that measures such as timely increasing law enforcement and propaganda, reasonably using high-efficiency, low toxicity and low residue pesticides, strengthening the protection of bird habitat, taking long-term bird banding monitoring, further exploring the rule of migration of Rustic Bunting, and promoting the recovering of bird populations.