[Objective]This study aims to investigate the method of distribution suitability of natural forests based on species distribution models, to examine the dominant environmental factors affecting the distribution of forest types and to generate the distribution suitability maps of major forest types. The results will provide the reference for natural forest restoration and structural adjustment in the region.[Method]Maximum entropy models were used for predicting potential distribution suitability for 11 natural forest types (including 7 mixed-species forests) in Jilin Province, northeast China. Data with tree species presence were obtained from permanent sample plots from the 8th Chinese national forest inventory (NFI) with natural origins collected in Jilin Province. Totally, 19 bioclimatic, 33 soil and 3 terrain environmental variables were included. Model accuracy was evaluated by AUC (area under the receiver operating characteristics curves) values, and the Jackknife test showed the importance of different variables which determined dominant variables affecting the distribution of forest types. Distribution suitability maps of 11 forest types were generated with five levels.[Result]The maximum entropy models were successful at discriminating between suitable and unsuitable habitat at the local scale for all 11 forest types, the AUC values were from 0.687 2 to 0.946 9 for calibration and test data. Among the values, one forest type showed "excellent", 7 forest types showed "very good", 2 forest types showed "good" and 1 forest type showed "fair". Therefore, the prediction results of the potential distribution of the 11 forest types in Jilin Province by the maximum entropy model were reliable. The environmental factors affecting the distribution of forest types were ranked as max temperature of the warmest month(for 10 forest types), elevation(for 8 forest types), mean temperature of the warmest quarter (for 7 forest types), and annual mean temperature(for 6 forest types) in terms of their importance to the distribution of the specific forest types. Therefore, temperature and elevation were the most important factors to the distribution of the specific forest types in the region. Potential distribution suitability mapping for 11 forest types were completed.[Conclusion]The maximum entropy model could reliably simulate the potential distribution area of forest types in Jilin Province. The dominant environment variables selected by the model were reasonable. The distribution suitability maps for 11 forest types could be as a reference for natural forest restoration and quality improvement in northeast China.

[Objective]To explore the influence of precipitation on water sources for Platycladus orientalis in Beijing mountainous areas and to provide a theoretical basis for understanding the response of P. orientalis to soil drought stress.[Method]We determined the hydrogen and oxygen values of xylem and investigated the water sources of P. orientalis in different precipitation conditions(A:no precipitation, 0.0 mm; B:1/2 precipitation, 12.7 mm; C:natural precipitation, 25.4 mm, D:two times of precipitation, 50.8 mm) by Iso-Source model during the vigorous growing season.[Result]P. orientalis showed a "plasticity root system" structure. It absorbed water from deep to surface soil layer with the precipitation gradients. In treatment A, P. orientalis mainly absorbed water from 60-100 cm and groundwater; the utilization rate was 31.5% and 32.8%, respectively. Similarly, in treatment B, it obtained water from 60-100 cm and groundwater; the utilization rate was 28.1% and 25.7%, respectively. But in treatment C, P. orientalis absorbed water from layer of 60-100 cm and groundwater; the utilization rate was 19.8% and 22.8%, respectively. At the same time, it absorbed water from the surface 0-20 and 20-40 cm soil layer; the utilization rate was17.8% and 22.9%, respectively. The water source of P. orientalis in treatment D was 0-20, 20-40, and 60-100 cm soil layer and groundwater with the utilization rate in the range of 20%-25.2%.[Conclusion]P. orientalis can adjust water source and its utilization ratio according to water conditions.

[Objective] Soil desiccation is a normal phenomenon in plantation forests in the Loess Plateau of China, which affects the growth and cultivation of plants. This study was conducted to analyze the impacts on soil water of different pruning and mulching treatments in jujube plantation in order to explore remediation technologies for soil desiccation in this region.[Method] The study sites was located in Mizhi County, Shaanxi Province, and the jujube trees were grown under rain-fed conditions. Soil moisture under 10 types of land surface management practices(4 different pruning intensities:traditional, slight, moderate and heavy pruning; 3 mulching treatments using straw, gravel and plastic film; traditional pruning + no mulching; heavy pruning + plastic film mulching; and farmland) were measured with CNC100 neutron gauges in 2012-2015.[Result] The soil desiccation in 15-year-old jujube plantation reached 560 cm in depth and annual water consumption was 19.7 mm more than the farmland. The degree of soil moisture improvement was increased with the increase of pruning intensity. The soil water storage within the top 300 cm soil layer of jujube plantations under straw, plastic film and gravel mulching treatments was 31.8-43.1, 69.9-71.4, and 84.0-92.7 mm respectively higher than that of no mulching jujube plantation. The combination of heavy pruning and plastic film mulching improved the soil moisture in growth periods and reduced the soil water loss in dormancy periods effectively, and under thus treatment soil moisture within 0-300 cm depth could recover to the same level as farmland in rainy years.[Conclusion] Practices combining pruning with mulching were more effective in conserving water in jujube plantation, thus, more helpful in preventing and mitigating the desiccation of deep soil in plantations in the semi-arid regions.

[Objective] The yield and quality of bamboo shoot depend upon species, site, climate, environment and cultivation techniques. High-yield cultivation techniques of sympodial bamboo shoot were mainly restricted in such traditional measures as adjustment of bamboo stand density and age structure, fertilization, shoot harvesting as well as disease and pest control in recent 5 decades. In this study, the different layers of branches on culm were controlled by pruning, and the distribution of endogenous hormone and nutrients in the above-ground organs and under-ground organs were investigated to study the regulatory mechanism of bamboo shoot yield by hormone and single sugar, which innovates shoot-oriented bamboo cultivation techniques and realizes the high-yield and effective bamboo cultivation model in a dwarf and horticulture way.[Method] Enzyme-linked immunosorbent assay(ELISA) and high performance liquid chromatography(HPLC) were adopted to determine the endogenous hormones and soluble sugar content of Dendrocalamus latiflorus shoot in field and potted cultivation subjected to different pruning. Meanwhile shooting situation and accumulated shoot yield were also investigated.[Result] With a high-yield cultivation model of D. latiflorus, one or two layers of bamboo branches were retained on a culm. The result showed that the single bamboo shoot weight, shoot number, average yield and cumulative yield of the 1-2 layers of bamboo branches left on a culm were significantly greater than those of other pruning treatments. The bamboo shoot yield of D. latiflorus was closely related to the kind and content of endogenous hormone in shoot body. During the whole shooting period, GA₁₊₃ content was significantly proportional to the single bamboo shoot weight, and IAA and ABA contents were positively correlated with the single bamboo shoot weight, while GA₄₊₇ content and ZR content were not significantly related to the single bamboo shoot. The IAA content of bamboo shoot treated by 2 layers of branches left on a culm was significantly higher than that with other treatments, and its IAA content reached the highest, with 109.53 μg·g^-1 FW at its shooting peak period. The bamboo shoot growth was mainly regulated by 3 kinds of hormones of IAA, GA and ABA. The change trend of IAA content was initially low and then high, which accords with the change pattern of IAA in the apical dominance theory. The glucose content was significantly correlated with fructose content, and their correlation coefficient was 0.90^[DK]**.[Conclusion] It is concluded that bamboo shoot growth of D latiflorus is mainly regulated by 3 kinds of endogenous hormones of IAA, GA and ABA, and carbohydrate. IAA would mainly promote cell elongation, and maintain a nutrient supply sink between bamboo stump or culm and bamboo shoot for carbohydrate transportation, distribution and metabolism to meet nutrient demand by fast-growing shoot. ABA could promote carbohydrate transportation and metabolism, and GA₁₊₃ promote cell elongation as IAA does. However, GA₄₊₇ seems to be a little function in bamboo shoot growing process. The main carbohydrate for bamboo shoot growth is sucrose, rather than starch; powerful bamboo's apical dominance is attributed by the high IAA concentration on the top.

[Objective] A orthogonal experiment on softwood propagation of Thuja sutchuenensis. was carried out to study the effects of different mother tree age, growth regulator, containers and substrates on the rooting rate and the root development indicators such as the number of adventitious roots, length of longest primary adventitious root, root dry mass. The internal and external environmental factors affecting softwood cutting propagation were investigated to provide theoretical and practical basis for the softwood propagation, introduction and domestication of T. sutchuenensis.[Method] An orthogonal experiment design of four factors and three levels(L9(3⁴)) was applied to study the softwood cutting propagation of T. sutchuenensis in the greenhouse of Chinese Academy of Forestry, Beijing. The rooting rate of cuttings with different treatments was investigated in 70 and 260 days after cutting. The number of adventitious roots, length of longest primary adventitious root and root dry mass per cutting were measured in 260 days after cutting. The statistical analyses of these indicators were conducted.[Result] Results indicated that:the age of mother tree had a great impact on the rooting rate and the root development of cuttings. The younger the mother tree, the higher the rooting rate of cuttings. Also, the younger the mother tree, the better the root development. The growth regulator(IBA) had a great impact on the rooting rate and the root development of cuttings. The rooting rate after cutting 70 days and the number of adventitious roots, length of longest primary adventitious root and root dry mass in 260 days after cutting were optimized by IBA(2 000 mg·L^-1) dipping in 2 minutes. The containers had little influence on the rooting rate, but it had a significant effect on the length of the longest adventitious root. The order of the merits of various containers was:black soft plastic nutrient cup > non-woven fabric nursery bag > white hard plastic nutrition cup. The effect of substrates on rooting rate varied with cultural time. The substrates had no significant influence on the rooting rate of cuttings after 70 days, but had a significant influence on the rooting rate of cuttings after 260 days. The mixed substrate with peat, perlite and vermiculite was better than that of the pure peat soil. The substrates had significant effect on the length of the longest primary adventitious root and root dry weight.[Conclusion] The rooting rate and the root development of T. sutchuenensis were not only influenced by individual factors, such as age, growth regulator, cutting container, cutting matrix, but also affected by but also affected by a comprehensive effect of those factors. With the change of root developmental stage, the dominant factors that affect the rooting rate and the root development indicators changed constantly. The best treatment for rooting rate of T. sutchuenensis softwood cutting propagation was:the cuttings from 3-year-old mother tree, the cutting by fast dipping treatment with GGR₆, and the containers of non-woven fabric and the mixed substrate with peat, perlite and vermiculite(V:V:V=1:2:1). The best treatment conditions for the root development were:the cuttings from 3-year-old mother tree, the cutting by fast dipping treatment with IBA, and containers of Black soft plastic and the mixed substrate with peat, perlite and vermiculite(V:V:V=1:1:1), with which the rooting rate was as high as 95%. Therefore, considering the two aspects of rooting rate and root development, this combination would have great application value in softwood propagation of T. sutchuenensis.

[Objective] Armeniaca sibirica is an important ecological and economic tree species. Its germplasm resources are very abundant. Identification and classification through morphological characteristics are difficult. In this paper, genetic diversity of superior clones of A. sibirica was analyzed and the fingerprints were constructed using SSR markers in order to provide a scientific basis for germplasm identification.[Method] Based on the results of simplified genome sequencing of A. sibirica, 600 pairs of SSR primers were synthesized, and screened for four A. sibirica clones. A total of 155 pairs of primers with clear bands were selected and used for PCR amplification for the 97 A. sibirica clones. The fingerprints were constructed by primer combination method and cluster analysis was carried out using UPGMA.[Result] Using 155 pairs of SSR primers, a total of 933 alleles were generated in the 97 A. sibirica clones. The number of alleles at each locus ranged from 3 to 11, with an average of 6.019. PIC of these loci ranged from 0.476 to 0.885, with an average of 0.681, indicating that the 155 loci were highly polymorphic. A total of 50 A. sibirica clones had specific alleles at 59 loci, and 89 clones had specific genotypes at 131 loci. All the 97 clones could be distinguished by the combination of primer L56, X47H, L79H, P40H and X47, and the fingerprints were constructed with the combinations. Genetic relationships of the 97 A. sibirica clones were analyzed, and the genetic similarity coefficients between the clones ranged from 0.669 to 0.943, with a mean of 0.757. Clustering analysis based on genetic similarity coefficients showed that the 97 clones could be divided into five categories, and the first category and the second category could be divided into three sub-categories respectively, which was consistent to a considerable extent with the clone origins.[Conclusion] In this study, 155 pairs of SSR primers were selected from 600 pairs, and the amplified loci had high polymorphism and good repeatability. It was found that 89 clones had specific genotypes, of which 50 had both specific genotypes and specific alleles. The fingerprints were constructed by the combination of 5 pairs of primers. The genetic differences among the clones were not significant, and the relationships among them were close. The results provide a scientific basis for germplasm identification of A. sibirica and lay a foundation for breeding of the species.

[Objective] This study was performed in coniferous plantations in Mao'ershan Experiment Forest centre of Northeast Forestry University. The three-dimensional structural parameters of individual tree canopy, which included treetops position, tree height, crown size and crown height, in the study area were extracted using airborne LiDAR data. And on this basis, the effective canopy was extracted to obtain the effective canopy of the stand.[Method] In this study, we used the local maximum window with variable window sizes to search the treetops of the crown, and to identify the treetops of individual tree crown and the extraction of individual tree. Using the crown treetops mark, marker-controlled watershed method was applied to segmentation algorithm into isolating individual trees. The vertical point cloud elevation detection method was analyzed to obtain the crown base height position, then the crown height was extracted. At the border of the canopy which was divided into marker-controlled watersheds, extraction of two crowns was contact height, averaging was taken as the effective crown of the stand.[Result] The results showed that the accuracy of tree isolation was 88.5%. The correlation analysis of the extracted values was carried out by using the measured data. The R² of tree height, crown diameter size and crown height was 0.886 2, 0.786 4 and 0.800 0, and the corresponding precision was 90.34%, 86.80%, 89.90%, respectively. The average contact height in the same forest stand was relatively stable. One-factor analysis of variance(ANOVA)was performed on the effective crown height of the extracted stands. No significant difference was found when the P-value was greater than 0.05.[Conclusion] A local maximum algorithm can be used by LiDAR to extract tree crown vertex and tree height. The variable size dynamic window is used to search for local maximum points. This method can improve the extraction accuracy of tree canopy structure parameters. Based on the tree top mark control watershed algorithm, the LiDAR data can be combined with the high spatial resolution navigation chip to complete the high-precision canopy extraction. The vertical direction detection method can extract the single crown length efficiently. In the same forest, the effective canopy of the stand is roughly the same. The airborne LiDAR can be able to extract the three-dimensional structure parameters of the single tree canopy, and can satisfy the extraction of the parameters of the single tree by the modern forestry survey and the extraction of the effective canopy of the stand.

[Objective] Qinghai Tibet railway is an important link in the development of the western region of China. As a result of the special natural environment, the frequent occurrence of wind sand disaster has become one of the most important factors affecting the safe operation of the railway. In this study, we used the Fluent software to simulate the different types of Qinghai-Tibet railway subgrade with sand barrier layout and analyzed its wind speed flow field and sediment characteristics. Our aim is to provide a theoretical basis for reasonable layout of sand prevention measures to reduce the accumulation of sand in the subgrade and is to ensure the safe operation of the railway.[Method] With the numerical simulation method, three kinds of subgrade(Ordinary subgrade, Ventilated subgrade, Sand-transmitting subgrade) and two sand barriers(Sleeper typed retaining wall, Sand blocking PE nets) combinations were selected to simulate the flow field and sand distribution, for evaluating the sand prevention effect of sand barrier and analyzing the affecting extent of the subgrade by wind erosion.[Result] Simulation result show that the wind speed field of three types of subgrade all had the same functional partition, and the wind speed had little effect on the flow field. On the windward side, the effect of ordinary subgrade on reducing wind speed was the strongest. Sands were easy to accumulate on the slope and the foot of the slope. The wind speed was significantly increased at the top of subgrade which may affect traffic safety. There was a reflow phenomenon at leeward, leading to the accumulation of sands on the leeward slope under gravity. The sand accumulation on the windward slope of common subgrade was serious and buried rail frequent. The ventilated subgrade would be affected by sand sediment, limiting the permafrost protection. The sand-transmitting subgrade prevented sand accumulation on the windward slope and rail. Once the occurrence of sand deposition on the transport pipeline, could be removed by natural wind. It was also easy to clean up and save a lot of manpower and resources. When the sand-break wall laying before the subgrade, the sand-break wall on the wind speed had a strong weakening effect. There was a deceleration zone between the subgrade and the sand-break wall, the wind speed could not reach the sand-driving wind speed. Sands deposited before and after sand-break wall, the amount of sediment accumulation on subgrade slope was greatly reduced.[Conclusion] Three kinds of subgrade in the absence of protective measures, there are different degrees of sand accumulation. The amount of sediment of sand-transmitting subgrade is minimal, and easy to clean up. The sand accumulation of Sleeper typed retaining wall on the wind side is greater than the leeward side. The sand accumulation of Sand blocking PE nets on the leeward side is greater than the wind. The spacing of sand barrier affects the effect of sand blocking. Appropriate adjusting sand barrier spacing to improve sand blocking effect. According to the simulation, the sand-transmitting subgrade is more suitable for the sandy area. However, the result are still in the theoretical stage and need to be further tested in Plateau environment.

[Objective]This study aimed to ascertain the correlation between forest spatial structure and population density of Cephalcia kunyushanica (Hymenoptera:Pamphiliidae) (abbreviated as "Ck" below) in a natural secondary Japanese Red Pine (Pinus densiflora) forest in Kunyu Mountain, and to explore ecological techniques by regulating forest spatial structure for controlling Ck, provide academic direction for ecological control of the forest pest.[Method]In this study, a six-hectares sample plot was set in Kunyu Mountain natural secondary German oak Red pine mixed forest, in which mingling degree index, neighborhood comparison index and uniform angle index were selected to analyze their relations with the population density of Ck.[Result]Results showed that there was a positive correlation between the population density of Ck and the uniform angle index of P. densiflora forest in Kunyu Mountain (R²=0.821; P=0.034), and the population density was negatively correlated with both the neighborhood comparison index of diameter at breast height (R²=0.903; P=0.013) and of tree height (R²=0.906; P=0.013), but no significant correlation was found between the population density with the mingling degree index (R²=0.177; P=0.481). On P. thunbergii forest, the population density of Ck was positively correlated with the uniform angle index significantly (R²=0.858; P=0.024), but there was no significant correlation between the population density of Ck with neighborhood comparison index of diameter at breast height (R²=0.043; P=0.739), neighborhood comparison index of tree height (R²=0.237; P=0.406), and mingling uniform index (R²=0.251; P=0.390). On P. resinosa the linear relationships between the population density of Ck with all the forest spatial structure indexes were not significant, including uniform angle index (R²=0.032; P=0.772), neighborhood comparison index of diameter at breast height (R²=0.180; P=0.447) and of tree height (R²=0.194; P=0.458), and mingling index (R²=0.653; P=0.098). Among the three species, the correlation between the population density of Ck with forest spatial structure indexes of P. densiflora or P. thunbergii was stronger than that with P. resinosa. In terms of spatial structure, the uniform angle index and neighborhood comparison index were better than mingling degree index.[Conclusion]The ecological regulation function of uniform angle index and neighborhood comparison index were better than that of mingling degree index for Ck population density. The relationship between forest spatial structures and population density of Ck can be utilized for forest management. The occurrence of the pest can be reduced by afforesting uniform forest of pine tree species to improve its resistant ability to Ck, and by reducing index of neighborhood comparison, that is, by improving forest growth condition.

[Objective] To provide basic data for developing the resources of 4 common wild species of Lauraceae plants (Neolitsea levinei; Neolitsea aurata var. glauca; Litsea elongata var. subverticillate; Litsea mollis) in Jinyun Mountain National Nature Reserve, we conducted a study on the extraction of the essential oil, identification of volatile components and composition of leaves of the 4 species.[Method] In this paper, the representative plant leaves were collected and the essential oil was extracted with steam distillation. The volatile components in the essential oil were separated and identified by GC-MS coupled with Computer Searching System and manual retrieval.[Result] The extracting rate of essential oil from the four species was 0.211 6%,0.063 4%,0.258 4%,and 0.698 2%, respectively. The extracting rate was the highest from L. mollis, while it was the lowest in N. aurata var. glauca. A total of 160 volatile components were identified from essential oils of the four species leaves, and among them N. Levinei had 78 ingredients mainly including Borneol acetate (9.11%), β-Eudesmol (7.85%), and 4-Terpineol (7.58%). N. aurata var. glauca had 65 components and was rich in 4-Terpineol (8.75%), Longifolene (7.72%), and β-Caryophyllene (6.79%). L. elongata var. subverticillate had 67, among which the dominant components were α-Bergamotene (7.72%), (1R)-α-Pinene (6.70%), and α-Caryophyllene (6.58%). L. mollis had 67 components, dominated by D-Limonene (8.46%), β-Elemene (7.66%), and trans-Geraniol (7.01%). The essential oil of N. Levinei was Borneol acetate type, that of N. aurata var. glauca was Longifolene type, that of L. elongata var. subverticillate was α-Bergamotene type, and that of L. mollis was β-Elemene/trans-Geraniol type. The difference of volatile components and content in leaves essential oil of the four species was largely oriented by their genetic background. There were 53 hydrocarbons, 48 alcohols, 19 ketones, 11 esters, 10 aldehydes, 4 naphthalenes, 2 benzenes and 13 others in the essential oils of the 4 species. The volatile components of the essential oils mainly belong to hydrocarbons and alcohols. Most of the hydrocarbons and alcohols have strong aroma, which should be the prime fragrance source of the 4 essential oils.[Conclusion] This paper revealed the composing types and characteristics of volatile components in leaves oils from four Lauraceae wild species in Jinyun Mountain and discussed their industrial applying value of the volatile components by literature analysis. This study provides a theoretical foundation for exploitation of wild species resources in Chongqing.

[Objective] To provide scientific basis for the identification and quality evaluation of agarwood, HPLC condition listed in"Chinese Pharmacopoeia"(2015) was improved, and the characteristic chromatogram for both wild agarwood and artificial agarwood was established.[Method] The analysis was carried out on a Phenomenex luna C₁₈ column(250 mm×4.6 mm,5 μm) with a gradient mobile phase of acetonitrile-0.1% formic acid at a flow rate of 0.7 mL·min^-1. The detection wavelength was set at 252 nm and the column temperature was 31℃. 29 batches of samples including both reference and validation ones were investigated. The chromatographic conditions were optimized and the precision, stability and repeatability of the method were investigated. The common characteristic peaks were analyzed with "Similarity Evaluation System for Chromatographic Fingerprint of Chinese Materia Medica".[Result] The results show that the precision, stability and repeatability of the method are good. The RSD of relative retention time of the characteristic peaks selected for either wild agarwood or cultivated agarwood is less than 2%. The results of 15 batches of validation samples show that the HPLC characteristic chromatogram of agarwood is accurate and effective for the identification of agarwood. 5 batches of adulterated agarwood among them cannot meet with the characteristic chromatogram, but the HPLC characteristic chromatogram of both 6 batches of wild agarwood and 4 batches of cultivated agarwood samples are consistent with those of agarwood.[Conclusion] 29 batches of samples contain both wild and cultivated agarwood, and the developed HPLC method shows good applicable to both wild and cultivated agarwood, which conforms to the requirements of method ology validation and can be used for the quality control of agarwood.

[Objective] The purpose of this paper is to investigate formation mechanism of tensioning stress of circular saw blade after laser shock process.[Method] Mechanical model for laser shock tensioning process of circular saw blade was reasonably simplified and built by ABAQUS finite element software. Tensioning stress field of circular saw blade after laser shock process was tested by static strain acquisition instrument.[Result] With the increase of shock wave peak pressure,the tangential tensile stress in the edge of circular saw blade is increased when laser pulse width is less than 20 ns, whereas increased first and then decreased when laser pulse width is greater than or equal to 20 ns. When shock wave peak pressure is about 6 GPa, the tangential tensile stress in the edge of circular saw blade reaches the maximum.[Conclusion] Tangential tensile stress is produced in the edge of circular saw blade after laser shock process with tensioning effect. Laser pulse width and shock wave peak pressure have different effects on tangential tensile stress in the edge of circular saw blade. The optimal shock wave pressure exists, which allows maximum tangential tensile stress in the edge of circular saw blade to be reached. The theoretical and experimental result were in good agreement. The laser shock tensioning process of circular saw blade is feasible. The adjustment of laser parameters can adjust the tensioning effect of circular saw blade.

[Objective] The evolution law of spatial pattern of the forest ecological-economic-social compound system based on spatial network was explored to promote the coordination and sustainable development of ecology, economy and society in Hunan.[Method] The paper adopted the theory of permutation and combination to evaluate the evolution of compound system based on the forest ecology-economy-society evaluation system, and classified according to the grade difference of each subsystem further. On this basis, we used spatial network theory to structure the spatial network that was composed of research units as nodes and the relationships between research units as edges. Then we assigned the edge weight by introducing spatial dependency to describe the position of nodes in local spatial patterns, and used the degree to define the key nodes and the research units that required adjustment. At last, the effective control method for optimizing the spatial pattern of compound system was proposed.[Result] The compound system was dominated by the ecologically dominant type and the relatively ecologically dominant type in Hunan, and showed a trend of diversification and high-level equilibrium development. According to the topological structure, the nodes of simplification and low-level equilibrium had greater influence and function in the spatial network, while the nodes of diversification and high-level equilibrium had less impact. Considering the spatial effect strength, the nodes of simplification and low-level equilibrium had relatively low status in the local spatial pattern and existed improvement space, while the nodes of diversification and high-level equilibrium played a more important role in the local spatial pattern, which had the function of radiation and demonstration.[Conclusion] The nodes of simplification and low-level equilibrium had great influence on the overall spatial pattern, but there was difficulty in the actual regulation. While the nodes of diversification and high-level equilibrium played an important role in the local spatial pattern, but the impact on the overall spatial pattern was relatively small, this was also the realistic problem of the spatial pattern optimization of the forest ecological-economic-social complex system in Hunan. Further studies on spatial networks of the degree and the spatial effect strength in 2015 indicated that under the guidance of the main idea of optimizing the spatial structure, the effective control method was to ensure the key nodes' position and focus on the research unit of existence improvement space in the evolution of compound system(space effect intensity is less than 0.5) and the influence on the overall spatial pattern was larger(node degree value is above 5).

[Objective] This paper presents a systematical review of the progress in studies of ecological stoichiometry in terrestrial ecosystem, which plays an important role in further understanding the material circulation and energy flow of terrestrial ecosystem.[Method]The databases of Web of Science, CNKI and others were used to summarize the progress in ecological stoichiometry in terrestrial ecosystems by consulting relevant literature.[Result]The study of ecological stoichiometry of terrestrial vegetation showed that C, N and P were the main objects in the field of ecological stoichiometry, of which N and P were the two most important limiting elements for the growth of terrestrial vegetation. The study of ecological stoichiometric characteristics of land soil showed that the ratio of carbon, nitrogen and phosphorus in soil was an important indicator for evaluating soil quality, and it was found that the ratio of carbon to nitrogen to phosphorus in soil was basically constant at the global scale. The study of nutrient limitation in terrestrial ecosystems showed that N:P was a sensitive indicator of plant growth nutrient constraints, and was often used to determine the threshold of nutrient limitation. Meanwhile, the content of N and P can also be used to determine the type of nutrient restriction. Climate, geography, soil and other factors were the main factors affecting the ecological stoichiometry characteristics of terrestrial plants.[Conclusion]In the studies of ecological stoichiometry of terrestrial ecosystem, C, N and P are important factors that scholars pay attention to and their ratio plays an important role in the evaluation of soil quality and nutrient limitation threshold.

[Objective] Based on the three realistic backgrounds of the "non-standard" behavior and the mandatory behavior of large scale land resources concentrated from administrative intervention in the land market, as well as the large differences of research conclusion of literatures, the paper discusses again the affecting factors of farmers behavior in forestland transferring scientifically and rigorously as the view of intention-behavior consistency from the aspect of individual endowment and cognition by subdividing sample data, and provides reference for promoting forest land transferring orderly, normally and sustainably.[Method] The method of binary Logistic model is used to establish four models for exploring the affecting factors of farmers intention and behavior in forestland circulation through the two reference groups of "no behavior, no intention" and "no behavior, with intention". The samples screen out the data of "behavior; with no intention"(mandatory behavior), "early behavior" and other disturbing conclusion.[Result] The characteristics of farmers who participated actually transfer-in forestland are higher per capita income, lower non-agricultural income, more planting timber forest, stronger attitude of forestland management and recognition. The characteristics of farmers who participated actually transfer-out forestland are higher per capita income, lower degree of farming, larger forestland area, lower degree of forestland fragment, more planting timber forest, stronger forestland management and risk falling cognition and recognition. Generally, comparing with farmers who fail to put their intention into action, the other farmers who took action actually of transfer-in forestland show that higher degree of education, higher per capita income, higher ratio of non-agricultural income, larger forestland area, more planting timber forest and more risk increasing cognition. Comparing with farmers who fail to put their intention into action, the other farmers who took action actually of transfer-out forestland show that older, larger forestland area, lower degree of forestland fragment, weaker forestland management cognition and stranger risk falling cognition.[Conclusion] Family capital is the key factor that successful contract behavior of farmers in forestland circulation. The affecting factors of behavior that farmers transfer-in forestland are household incomes per capita, non-agricultural income, forest category, the attitude of forestland management and forestland circulation cognition. The affecting factors of behavior that farmers transfer-out forestland are household incomes per capita, forestland area, the occupation of a household head, the degree of forestland fragment, forest category, the attitude of forestland management, risk perception and forestland circulation cognition. Due to restricting from factors, a large number of farmers fail to put their intention into action. Such as political resources, behavior ability and family capital constraints farmers transfer in forestland, and resources endowment(such as small scale, the degree of fragment) constraints farmers transfer out forestland. At the same time, there are many differences between the group that farmers have participated forestlands circulation actually and the group that who farmers have intention participated forestland circulation but no action. The proportion from administrative intervention promoting forestland market allocation is higher. Therefore, in order to effectively improve the contract ratio of forestland circulation, it is necessary to improve the institutional system, grasp the scale of administrative intervention, give full play to the functions of the government, and strengthen the construction of social security in rural areas.

[Objective] Using embryogenic lines of larch, a suspension culture system suitable for embryogenic callus development was established and optimized to explore the main factors affecting the tissue proliferation. On the basis of these, somatic embryo maturation induction of suspension tissue was carried out. It aims to set up a basis for rapid proliferation of embryogenic callus and large-scale propagation of somatic embryos.[Method] The subculture of embryogenic calli of Larix olgensis, L. gmelinii ×kaempferi and L. kaempferi ×olgensis was carried out, and the fresh proliferated tissues were selected for the suspension culture. In order to optimize the appropriate culture conditions, the orthogonal array of L₉(3⁴) was designed and verified by a test, in which the proliferation amount and the proliferation rate of the embryogenic callus were taken as the response values. The embryogenic tissue obtained from suspension proliferation was used for somatic embryogenesis, and the number of somatic embryos was counted.[Result] In the process of larch suspension culture, the influence of initial inoculation quantity, shaking intensity and suspension culture time on the proliferation of the embryogenic callus was very significant. The proliferation amount and the proliferation rate of the embryogenic suspension tissue were decreased with the increase of inoculation amount, and a tendency of first increase followed by a decrease with increase of shaking intensity was exhibited; with the increase of incubation time, the amount and rate of proliferation were both increased. The 4 g·L^-1embryogenic callus was cultured in the BM medium containing 2,4-D 0.15 mg·L^-1, 6-BA 0.05 mg·L^-1 and KT 0.05 mg·L^-1 (SCM)under the condition of light avoidance and the 120 r·min^-1 shaking intensity. The three lines of Larix embryogenic callus can proliferate rapidly and steadily. The proliferation rates of the three lines after 15 days suspension culture were 2 569.42%, 4 189.96% and 3 001.67% respectively, showing a significant interspecific differences. The mature cultivation mode has significant effects on the amount of somatic embryos in the suspension culture(P=0.000). The embryogenic callus obtained from the suspension culture was inoculated to the solid proliferation medium(PCM) containing agar 6 g·L^-1 for 15 days, then transferred to 1/4 BM medium with inositol 10 g·L^-1(TCM) for 14 days, and then transferred to the somatic embryo maturation medium containing ABA 20 mg·L^-1, AgNO₃ 5 mg·L^-1, and PEG₄₀₀₀ 80 g·L^-1 for 8 weeks. The results showed that the amount of somatic embryogenesis increased significantly(P=0.000). The number of somatic embryogenesis of the three Larix embryogenic lines OO-A1,GK-F1 and KO-H was (101.69±11.19), (93.09±9.34) and (5.78±1.47) embryo·g^-1respectively.[Conclusion] Suspension culture can obtain a large scale of Larix embryogenic calli with uniform dispersion and high quality in the short term, without affecting the somatic embryogenesis and maturation. After 15 days of dark culture, in the BM liquid medium(SCM) the fresh weight of the embryogenic tissue of Larix can be increased by 26.99-42.90 times when the inoculation amount of callus was 4 g·L^-1 and the shaking intensity was 120 r·min^-1. Before the somatic maturation induction, the embryogenic suspension callus was first cultured in the solid proliferation medium(PCM) for 15 days and then transferred into the transitional medium(TCM) for 14 days, after which the amount of the somatic embryogenesis could be significantly increased.

[Objective] This paper investigated the effects of exogenous citric acid on a series of growth and physiological characteristics of Pinus massoniana seedlings under aluminum toxicityto find the optimal alleviating concentration of citric acid, and reveal the physiological mechanism how exogenous citric acid alleviates aluminum toxicity, in order to provide theoretical basis for the growth of P. massoniana in soil acidification areas.[Method]In this study,two different families of P. massoniana seedlings (aluminum-resistant FJ5, aluminum-sensitive GD20) were used to investigate the effects of exogenous citric acid on P. massoniana subjected to aluminum stressin a hydroponic experiment. The height increment contents, the form of root, as well as the activities of antioxidant enzymes (POD, SOD, CAT, APX, GR), the contents of active oxygen (H₂O₂ and O₂^·), osmotic adjustment substances (soluble sugar, soluble protein, free proline) and malondialdehyde (MDA) in the leaves of P. massoniana seedlings were measured under different concentrations of exogenous citric acid. The Principal Component Analysis was applied to explore the main physiological indexes during the process of exogenous citric acid to alleviate the aluminum poisoning of P. massoniana.[Result]Aluminum stress decreased the length, surface area, volume, diameter of P. massoniana seedling roots and the height increment, inscreasedthe activities of antioxidant enzymes in the leaves, and the contents of H₂O₂, O₂^·, MDA and osmotic adjustment substances in the leaves. After applying exogenous citric acid, the length, surface area, volume, and diameter of the root, and the seedlingheight increment increased, the activities of antioxidant enzymes in the leaves enhanced, and the contents of H₂O₂, O₂^·, MDA and osmotic adjustment substances in the leaves reduced. Compared with FJ5, GD20 had greater change range. Principal component analysis showed that the contribution rate of each index in the first principal component was MDA > H2O2 > Proline > GR.[Conclusion]Active aluminum has an obvious toxic effect on P.massoniana seedlings; Exogenous citric acid could effectively alleviate the toxicity of aluminum on P.massoniana seedlings, and it had a better effect on aluminum-sensitive variety than aluminum-resistant variety. The alleviating effect of exogenous citric acid on the aluminumtoxicityvarieddependent on the different concentrations of citric acid.The optimum concentration of citric acid was 0.02 mmol·L^-1 among all applied concentrations, and whenthe concenatrations was greater than 800 mmol·L^-1, the alleviating effects of citric acid was inhibited. MDA and H₂O₂ may be the key indexes of exogenous citric acid to alleviate aluminum toxicity.

Based on the forest fire data in Jilin from 1969 to 2013, the characteristics of the forest fire sources were analyzed, which would provide reference for fire source management and forest fire prevention in Jilin Province.[Method]Based on the forest fire data of Jilin Province, the interannual variation of forest fire sources in Jilin Province were analyzed by using Microsoft Office Excel to draw charts, by which the main fire sources of forest fires in Jilin Province were determined. The significant differences between the main fire sources were analyzed by using One-Way ANOVA, and damage level of fire sources was obtained according to the results of multiple comparisons and the mean value map.[Result]The number of forest fires with known fire sources was 5 216 from 1969 to 2013 in Jilin Province, accounting for 75.35% of the total forest fires; the burnt area was 103 162.70 hm², accounting for 63.63% of the total fire area; the burnt forest area was 51 316.88 hm², accounting for 55.15% of the total burnt forest area. At present, there are 23 forest fire sources in Jilin Province and the main forest fire sources are crop residue burning, arson, sacrificing fire, Foreign burning, heating and cooking in the wild, smoking in the field, especially crop residue, foreign burning, and smoking. The number of forest fires, forest area burnt, and total area burnt resulting from the three fire sources accounted for 64.63%, 71.90%, and 67.33% of the total, respectively. The arson, sacrificing fire, and field heating and cooking have obvious rising trend. Crop residue burning occurred most frequently and concentrated mainly in 1969 to 1985. Forest fires caused by crop residue burning accounted for 41.78% of the total number, and their damage to the forest was the biggest, accounting for 54.17% of the total. Forest fires resulting from smoking occurred very frequently (22.03%) and remained continuous state from 1969 to 2013 causing significant damage (15.51%). Forest fires caused by transit fire from 1974 to 2013 totaled 43 (0.82%), but did real harm (2.22%) to the forest. Forest fires caused by sacrificing fire occurred more frequently from 1970 to 1989, and went down gradually from 1990, but started to go up in 2002. Due to such activity as paper burning around Tomb-Sweeping Day in April, sacrificing fire accounted for 9.51% of the total number. Foreign burning brought the biggest damage every time, followed by field heating and cooking, crop residue burning, smoking, sacrificing fire, and arson in Jilin Province. If a forest fire is caused by transit fire is not well controlled, it is likely to develop into a major catastrophic forest fire.[Conclusion]The main forest fire sources in Jilin Province are now crop residue burning, arson, sacrificing fire, foreign burning, field heating and cooking, smoking, and prevention and control of those fire sources should be strengthened.

[Objective]This aimed to investigate the whitefly species infesting bamboos in China to provide a basis for species identification and pest control.[Method]The whitefly was collected on bamboos, and the specimens were mounted on glass slides and observed under a microscope.[Result]In this paper, three species of whitefly infesting bamboos are reported:Aleurocanthus longispinus Quaintance & Baker, a newly recorded species in China; Aleurolobus marlatti (Quaintance), a new host-plant association; as well as Crenidorsum multipapillus (Singh). We re-describe the morphological characteristics of puparium of the three species and provide the host plants, geographic distribution and the live images, slide photographs of the three whitefly species. The specimens have been deposited in the Insect Collection of Zhejiang Agriculture & Forestry University, China. In addition, we surveyed literature and found that there are totally 21 whitefly species in 11 genera belonging to one subfamily, which are harmful to bamboo plants in the world.[Conclusion]There are three whitefly species which harm bamboos in the southern and eastern China. In the future, the scope of investigation on whitefly should be expanded to further know well the whitefly species and distribution as well as their harm to bamboos in China.