Objective: By comparing population structure and seedling growth of Quercus acutissima among three different community types, the purpose of the study was to illustrate the quantitative and structural dynamics of Q. acutissima populations, in order to provide a basis for forest restoration and management in Qiaoshan forest region, southern Loess Plateau, China. Method: Field survey was conducted in 12 fixed plots(3 different stand types×4 reduplicates). All Q. acutissima individuals(DBH>4 cm) were measured for DBH(ground diameter for seedlings), height and crown width. Biomass of different organs was also measured for typical seedlings sampled from each plot. By substituting diameter class for age class, the static life table and survival curve were draw according to the survival amount of Q. acutissima in each diameter class. Differences among growth characteristics(height, ground diameter, crown width, and biomass allocation) of 1-10 years seedlings in three community types were analyzed. Result: The number of individuals tended to decrease with age in all of the three stand types of Q. acutissima, i.e. the low age classes displayed an absolute advantage in number of trees, indicating that the Q. acutissima population is progressive in Qiaoshan region. The static life table of the Q. acutissima population showed that the highest mortality rate occurred at younger diameter class indicating the phase was the most vulnerable stage in life history of Q. acutissima. The life expectancy was the highest in age classes ofⅠand Ⅱ. The mortality of Q. acutissima between age classes of Ⅲ to Ⅳ is far lower in mixed forest of Q. acutissima with broad leaved tree and mixed forest of Q. acutissima with Pinus tabulaeformis than that in pure forest of Q.acutissima. The survival curve of the different Q. acutissima populations was Deevey-Ⅲ type. The ground diameter of seedlings for 1-5 years were larger in the pure forest than in the mixed forest, with the increase of age, the ground diameter of seedlings in Q. acutissima with P. tabulaeformis forest was slightly higher than the other two forest types, but the difference was not significant. The crown width for 2-10 ages was larger in the mixed forest than in the pure forest, and the differences were insignificant among the three forest types in 1-3 years but significant after 4 years. The height of the seedlings of 2-10 ages in the mixed forest of Q. acutissima with P. tabulaeformis was larger than in the mixed forest of Q. acutissima with broad leaved trees and in the pure forest of Q. acutissima. The differences of seedling height among three forest types became significant after 5 years. The biomass of leaves, stems, branches and roots of Q. acutissima seedling in three forest types all increased exponentially with age. The effect of forest types on seedling organic biomass depended on ages(but for root biomass). The effects on leave biomass were insignificant at 1-6 years of age and significant after 7 years, the effects on stem biomass were insignificant at 1-4 years and significant after 5 years, and the effects on branches biomass were insignificant at 1-2 years and significant after 3 years. However, the effect of forest types on seedling root biomass was independent with age. Conclusion: Q. acutissima populations among three representative forest types in Qiaoshan forest region were all developed well with adequate regeneration ability. Although the quantity of young seedlings in pure Q. acutissima forest was relatively high, the mortality rate was also rather high, and the growth characteristics and biomass of older seedlings were lower than that in the mixed forests. The number of larger individuals with high quality in mixed forests was more than that in pure forests. We concluded that the construction of mixed forests has higher wood productivity and more stable community structure, which should be the main direction for forest management in the future.

Objctive: This study aims to characterize snowfall outside forest, penetrated snowfall inside forest, and canopy intercepted snow, and hence to deepen understanding of the effects of forest canopy on snowfall interception and the penetrated snowfall in Korean pine forests in the Xiaoxing'an Mountains. Method: Characteristics of snowfall outside forest, penetrated snowfall inside forest, and stand structure were measured in 2 successive years using positioning observations. A semi-empirical theoretical model was used to introduce and conduct snow interception simulations at the stand level in the Xiaoxing'an Mountains region. Result: During the winter period from November 2013 to April 2014 and November 2014 to April 2015, 17 snowfall events were observed, and the average total amount of snowfall each time was 10.3 mm, the average intensity of snowfall was 4.41 mm·d^-1, and the average through-snowfall each time was 7.4 mm, with an average proportion of through-snowfall of 69.3%. Through-snowfall and through-snowfall rate increased with the increase of snowfall. Snow interception and fall showed a strong power function correlation, but snow interception and canopy density showed a strong negative correlation(P < 0.05). Snow interception efficiency and snowfall showed a negative exponent function correlation(P < 0.05). This study demonstrates the limitations of the forest canopy in its capacity to intercept snow. Snow interception efficiency gradually decreases with the increase of snowfall and is particularly sensitive to the amount of snowfall and canopy density(P < 0.05), although it shows no significant correlations with average diameter at breast height, tree height, basal area, canopy height, canopy width, leaf area, or slope gradient. Conclusion: Snowfall and canopy density have a significant effect on the canopy interception. Snowfall, average diameter at breast height, canopy density, tree height, and slope gradient have a significant effect on through-snowfall. The Pomeroys interception model and the revised one provide a satisfactory simulation of snow interception of Korean pine forest in the Xiaoxing'an Mountains.

Objective: The study was aimed to investigate the patterns of impacts of acid rain at different intensities on total soil respiration rate(R_s) and its components of soil heterotrophic respiration rate(R_h) and soil autotrophic respiration rate(R_a) in Pinus elliottii plantation, in order to improve our understandings of the process of soil respiration and further to provide a scientific basis for forest management under environmental stresses such as acid deposition. Method: We conducted a one-way factorial acid rain addition(CK: pH 6.5; low acid addition level(LA): pH 4.5; high acid addition(HA): pH 2.5, with 3 replicates) field experiment in a subtropical P. elliottii plantation in China. The trenching method was used to separate the heterotrophic and autotrophic soil respiration. From January to December of 2015, the R_s, R_a, R_h effluxes were measured twice a month using a LI-8100A automated soil CO₂ flux system. Soil temperatures and soil volumetric water content and soil biochemical properties adjacent to each soil respiration points were simultaneously detected. Result: R_s, R_a, R_h showed clear seasonal dynamics with similar single peak curves in all treatments, and were mainly driven by the surface soil temperature. Compared to the R_s under CK, the R_s under LA and HA were significantly reduced by 25.83% and 30.95%(P < 0.05). Also, LA and HA treatments inhibited the R_h effluxes by 29.60% and 35.20%(P < 0.05), reduced the R_a effluxes by 19.15% and 23.40%(P < 0.05). The inhibitory effect of simulated acid addition on soil respiration rates only showed in the growing season. R_a even being promoted in non-growth season(P < 0.05). In the CK plots, R_h accounted for 63.94% in R_s, and the proportion was significantly reduced(P < 0.05) in the LA and HA treatments. The intensity of R_a increased with the enhancement of acid rain. There were significant exponential correlations between R_s, R_h, R_a and soil temperature(P < 0.01), and both addition levels of the simulated acid rain could reduce the temperature sensitivity coefficient of soil respiration. Surface soil moisture was significantly related to the total soil respiration rates and the two main components under HA treatments(P < 0.01). The combined action of soil temperature and soil moisture also had a significant impact on soi respiration(P < 0.01). The variation of R_h was mainly controlled by the activity of soil urease and soil sucrase, topsoil organic carbon(TOC) and soil pH, while the R_a rates were mainly influenced by the soil urease activity, soil temperature and TOC, and the these factors jointly contributed 83.9% to the variation of R_s. Conclusion: The seasonal characteristics of soil respiration and its main components were similar and mainly controlled by surface soil temperature. Simulated acid rain exacerbated soil acidification, and significantly changed soil enzymes and soil organic carbon, which caused the inhibitory effects of R_s mainly due to R_h and R_a, and the changes of soil hydrothermal status induced the inhibition effects more obvious in the growing season. The proportion of R_h in the total soil respiration decreased with the increase of simulated acid rain intensities, but in the short term, the R_s variation was mainly controlled by the change of R_h.

Objective: The aim of this study was to investigate the internal physiological mechanisms of Hemiptelea davidii adapting to different soil water environments by comparing the effect of microenvironments(interdune and upperdune) with different soil water conditions on the characteristics of xylem hydraulic architecture, leaf water relations and photosynthetic gas exchange of H.davidii, in order to provide a theoretical basis for windproof and sand fixation afforestation and vegetation restoration in Horqin sandy land. Method: In this study, the H.davidii inhabiting in the interdune and upperdune with different soil water conditionsin Horqin sandy land was targeted. The differences in water transport efficiency and safety of H. davidii in the two habitats were analyzed from the perspective of trees hydraulic architecture, and a comparative study on leaf water relation, photosynthetic gas exchange and xylem anatomical structure was conducted. Result: Soil water status in interdune was much better than that in upperdune, thus H. davidii growing in interdune presented the larger conduits, and significantly higher stem water transport efficiency(K_s) and leaf and stem water potential(P < 0.05). Although, there was no significant difference in leaf photosynthetic carbon assimilation rate between the two habitats, the stomatal conductance(g_s) and intrinsic water use efficiency(WUE_i) showed significantly different. g_s of the upperdune was significantly lower(P < 0.05), and its WUE_i was significantly higher(P < 0.05).Different soil water content in habitats also had significant impacts on the ratio of leaf area to sapwood area(LA/SA) of H. davidii, the value of LA/SA was significantly higher ininterdune than that of upperdune habitat(P < 0.05). Growth indicators such as basal diameter, tree height and aboveground biomass were also significantly higher in interdune than those of the upperdune habitat(P < 0.05). H. davidii in the upperdune showed higher wood density and stronger resistance to cavitation, and the hydraulic safety margin(HSM) was also wider(larger values of Ψ_S-md-P₅₀ and Ψ_S-md-P₈₀). Conclusion: Growing in the interdune habitat with less water-limited environment, H. davidii tends to have larger conduits which facilitate higher water transport efficiency and ensure higher growth rate and competitiveness. On the contrary, in the upperdune habitat with more water-limited environment, it tends to have smaller conduits. Although this strategy reduces the water transport efficiency of xylem, it helps to obtain stronger resistance to cavitation, thereby ensuring the long-term survival of plants undersevere water stress. The strategy of adjusting hydraulic architecture traits of H. davidii with different water conditions reflects its stronger drought resistance and adaptability.

Objective: To verify that the addition of exogenous ethylene can promote the root growth of Chinese fir seedlings under phosphorus stress and improve the utilization rate of phosphorus to adapt to adversity. Method: The seedlings of Chinese fir from No. 25 half-sib family cultivated at the seed garden of Wuyi National Forest Farm in Zhangping, Fujian Province, which were selected as experimental materials. Two phosphorus(P) levels of low P supply(P₀: 0 mmol·L^-1 KH₂PO₄) and normal P supply(P₁: 1 mmol·L^-1 KH₂PO₄) were set. Three reagent treatments were designed at different P levels(E+: 200 mg/L ethephon, 0:no additive reagent, E-: 5 mol·L^-1 ethylene synthesis inhibitor CoCl₂). After 30 days of treatment, ethylene in roots was collected by headspace method, and indexes such as seedling height, ground diameter, root morphology, P content and dissolution rate of cortex cells in Chinese fir seedlings were measured. Result: 1) Phosphorus stress and exogenous ethylene both promoted the increase of endogenous ethylene in the roots of Chinese fir seedlings, and the ethylene content in roots treated with exogenous ethylene(E+) was higher than that of other treatments at different phosphorus supply levels, With the increase of endogenous ethylene content, the ability of seeking phosphorus in the roots of Chinese fir seedlings is enhanced, the phosphorus content in the shoots and roots is significantly increased, and the phosphorus utilization rate is improved. 2) Under phosphorus stress, the increment of seedling height in the treatment with exogenous ethylene(E+) was significantly lower than that in the treatment with ethylene inhibitor(E-) and the treatment without ethylene inhibitor(CK), while the increment of ground diameter was the opposite.3) The addition of exogenous ethylene treatment(E+) increased the growth of root length, average root diameter and root volume increment of Chinese fir seedlings, and each index was positively correlated with the absorption of available phosphorus in soil by roots, which promoted the absorption of phosphorus in soil by roots of Chinese fir seedlings. 4) Under phosphorus stress, the addition of exogenous ethylene treatment(E+) increased the lytic rate of the root cortex, and the three treatments reached an extremely significant level, while the difference was not significant under normal phosphorus supply environment. Conclusion: Under phosphorus stress, the content of ethylene in roots of Chinese fir treated with exogenous ethylene had a significant correlation with the morphological growth of roots, and the ground diameter, root length, average root diameter and root volume of Chinese fir increased significantly. Under phosphorus stress, the addition of exogenous ethylene increased the phosphorus content and root ethylene content of Chinese fir seedlings and increased the lytic rate of root cortex cells. In order to further reveal the mechanism of exogenous ethylene as the key factor of phosphorus regulation on the growth of Chinese fir seedlings under phosphorus stress.

Objective: In the present study, we explored optimal fall fertilization regime by investigating seedling quality and field performance of Populus tomentosa in order to provide a theoretical basis for nursery accurate fertilization management. Furthermore, we examined the inner-mechanism of growth and nutrient resorption in field. Method: In this study, triploid P. tomentosa was used as experimental materials. Fertilization was carried out in fall after the formation of terminal buds, once a week for consecutive six weeks (from September 2 to October 7). A completely randomized block design with one factor was used to set four fertilization levels: 0, 5, 10, 20 g fertilizer per seedling totally (a water-soluble commercial fertilizer: 20%N + 20%P₂O₅ + 20%K₂O + TE). Seedling height, diameter and stem biomass (or stem volume) were measured at the beginning and end of each growing season. We also determined nutrient concentration and non-structural carbohydrate (NSC) levels in stems and roots in nursery, as well as nutrient concentration in green and senesced leaves in field. Result: 1) In nursery, fall fertilization had little effect on seedling growth, but significantly increased N and NSC accumulation, especially in roots. The N concentration in stems and roots increased by 2.4%-12.0%, 17.4%-48.1%, respectively, and the root starch concentration increased by 17.9%-34.5%. Fall fertilization with N, P and K was mainly enhanced N storage but no significant effect on P or K storage, indicating the preference for N utilization. 2) In field, the growth of height, diameter and stem volume reached the maximum when the fertilizer amount was 10 g per seedling (increased by 40.0%, 80.4%and 85.3% respectively compared with the control), fully exhibiting the effects of fall fertilization in the nursery. When fertilization rate increased to 20 g per seedling, the seedling growth was inhibited and the survival rate the minimum of (63.3%) after afforestation. The result demonstrated that it is important to optimize fall fertilization rate. 3) Furthermore, the enhance of growth (10 g fertilizer per seedling) increased N resorption efficiency (71%) and decreased N leaching loss from deciduous leaves (56.4%). 4) Our results also showed that the changes of nutrient resorption were associated with shifts of multi-elements in leaves rather than single-element. Nitrogen resorption was negatively related to N and K concentration in senesced leaves, while positively related to P concentration in green and senesced leaves. Phosphorus resorption was positively related to N concentration in green leaves. Conclusion: N storage, NSC levels with field performance of seedlings are important indicators to evaluate the effect of fall fertilization. Infield, the increments of growth increase N resorption from leaves and sequence, decrease N leaching. It is paramount to optimize fall fertilization rate, however it is particularly important to determine the reasonable amount of fertilization in fall. Nutrient storage, NSC accumulation and field performance of triploid P. tomentosa seedlings are benefit when fertilization rate is 10 g fertilizer per seedling, but when fertilization rate is 20 g fertilizer per seedling, it has a negative effect.

Objective: The flower and fruit characteristics, growth and development habits of Camellia hainanica are obviously different from other Camellia species, and its ploidy is still unclear. This study uses flow cytometry and chromosome counting to clarify the ploidy of C. hainanica, which provides a basis for deployment of pollen trees and studies of genetics and breeding in the future. Method: Firstly, diploid Camellia fluviatilis var. megalantha was used as a control, and young leaf samples of 60 elite trees of C. hainanica were collected, fluorescence intensity of the DNA content of each sample was measured by flow cytometry(FCM), the ploidy of samples was estimated according to their DNA peaks. Secondly, according to the results of flow cytometry, diploid C. fluviatilis var. megalantha was used as a control, a total of 34 representative trees were selected, including different ploidy C. hainanica from different regions, and samples of root tips were collected for counting their chromosome numbers using electron microscope, so as to verify the results of flow cytometry. Result: The detection by flow cytometry showed that: The DNA peak of diploid C. fluviatilis var. megalantha was 50.39. Among the 60 samples of C. hainanica, 8 samples showed a range of DNA peak of 205.50-213.42, indicating an octoploid compared to the control, and 50 samples showed a DNA peak range of 243.16-256.11, indicating a decaploid. The DNA peaks of CMZX-612 and TCXYL-61 were 177.09 and 188.02, doubted to be a heptaploid. The coefficient of variation of the DNA peaks was less than 5% for most of the tested samples. And the chromosome counting showed that: The chromosome number of diploid C. fluviatilis var. megalantha was 2n=2x=30. Among the 34 samples of C. hainanica for testing, 8 root tip samples were octoploid(2n=8x=120), including CMZX-612 and TCXYL-61 doubted to be heptaploid detected by the flow cytometry, chromosome counting confirmed that they are actually octoploid(2n=8x=120). 26 root tip samples of C. hainanica were decaploid(2n=10x=150) detected by the chromosome counting, basically the same as those estimated by flow cytometry. Conclusion: The flow cytometry and chromosome counting both indicated that the 60 tested samples of C. hainanica had two ploidies, octoploid(2n=8x=120) and decaploid(2n=10x=150), of which decaploid accounted for 83.3%. C. hainanica is a newly discovered species of the genus Camellia, and its ploidy is obviously different from other species in Camellia. Determination of ploidy of C. hainanica provides a significant basis for further studies on inheritance and evolution of polyploidy, as well as parents selection for cross breeding and identification of germplasm resources.

Objective: Nitrogen is one of macroelements necessary for plant growth and development,and ammonium nitrogen is one of the main nitrogen sources available for roots. Ammonium transporter(AMT) plays an important role in the acquisition and transport of ammonium nitrogen. Fast growth is the most important feature of Moso bamboo(Phyllostachys edulis). The identification of AMT genes in Moso bamboo,and the systematic analysis of their structures and expression patterns will lay the foundation for in-depth study on the function of AMT genes in rapid growth of Moso bamboo and its environmental adaptability. Method: Bioinformatics methods were used to identify the gene members of AMT family in Moso bamboo. Furthermore,their phylogeny,structural characteristics,tissue expression specificity,and responses to hormones and abiotic stresses were analyzed,and the expression patterns of key genes under drought treatment were verified by qPCR. Result: A total of 13 AMT family genes were identified in the genome of Moso bamboo,named PeAMT1-PeAMT13. The proteins encoded by PeAMTs were 408-497 amino acids in length,and the subcellular localization prediction showed that all PeAMTs were located on the plasma membrane. Phylogenetic analysis showed that PeAMTs were divided into two subfamilies,and each of which had its own specific motifs,but all PeAMTs contained the typical conserved sequence in Motif 2 of ammonium transporters. The collinearity analysis showed that eight pairs of PeAMTs had collinearity,and 11 PeAMTs had collinearity with eight OsAMTs. PeAMTs were subjected to purification selection. PeAMTs had tissue expression specificity,most of which had the highest expression level in roots and leaves,followed by shoots at early stage of growth,and lower expression levels in shoots with higher lignification at late stage of growth. A variety of hormones and abiotic stress response elements were found in the promoter of PeAMTs. The treatments of GA₃,brassinolide(BL) and drought all caused significant changes in the expression of most PeAMTs,and NAA and low temperature treatments also resulted in significant expression changes of six PeAMTs(P < 0.05). The key genes PeAMT1,PeAMT2,and PeAMT3 were screened for qPCR verification under drought treatment,and the expression changes of the three genes reached significant levels(P < 0.05). Conclusion: There were 13 PeAMTs encoding complete AMT in Moso bamboo,which had certain differences in structural characteristics and tissue expression specificity,and their expression was affected by hormones and abiotic stresses. PeAMTs might help Moso bamboo to obtain ammonium nitrogen from the soil by a high expression in the roots,and transfer and recycle ammonium nitrogen in the leaves with a high expression to ensure sufficient nitrogen supply during the rapid growth of Moso bamboo. Meanwhile,PeAMTs might function in ammonium detoxification for improving the resistance of Moso bamboo.

Objective: Accurate plantation map plays an important role in sustainable forest resource management. In this paper,a multi-feature classification method based on Sentinel-2 optical and Sentinel-1 SAR data combination was proposed for discriminating and mapping typical plantation species in the tropical region. Method: 43 spectral features were extracted from a scene of Sentinel-2 image. Their importance was sorted through the out-of-bag(OOB) error estimation,to select out the optimal spectral features for plantation species classification. In addition,4 textural features were also calculated from the Sentinel-2 image to represent the spatial information of each plantation species,and 4 backscattering coefficient features were extracted from Sentinel-1 SAR image to represent the structural characteristics. Then,different combinations using the selected spectral features,together with textural and backscattering coefficient features were input to the random forest classifier for plantation species classification. The performance and contribution of different combinations were assessed based on their classification accuracies. Result: 1) The OOB score reaches the highest value of 0.947 2 when the top 17 important Sentinel-2 spectral features are employed. Among them,blue,red-edge,NIR spectral bands,and vegetation indices based on NIR and red-edge bands have a high importance for plantation species identification. 2) Eucalyptus,oil palm and rubber plantations show some differences in different textural features. Among the three plantations,oil palm has the largest CON(contrast) and ENT(entropy),and the smallest ASM(angular second moment) value,while eucalyptus has the largest ASM and COR(correlation),and the smallest ENT value. For rubber,the values of CON and COR are the smallest,while the values of ASM and ENT are between those of eucalyptus and oil palm. The backscattering coefficients of the three plantations also exhibit much separability,especially for the ratio of VV to VH. 3) When only the Sentinel-2 spectral features were used for plantation species classification,the F₁ values of eucalyptus,oil palm and rubber plantations were 0.61,0.74 and 0.70,respectively. However,the combination of spectral features,textural features and backscattering coefficient features have been seen the highest classification accuracy,with the overall accuracy and Kappa coefficient of 85% and 0.83,respectively. The F₁ values of eucalyptus,oil palm and rubber plantation increase by 0.19,0.15 and 0.10,respectively. Conclusion: The spectral bands of Sentinel-2 optical image could provide an important basis for plantation species recognition,while the derived textural features and the backscattering coefficient features extracted from Sentinel-1 SAR image may also provide supplementary information which contributes a lot to the identification of different plantation species. Considering the high temporal and spatial resolution of Sentinel-2 and Sentinel-1,the integration of spectral,textural and structural information might show great potentials to improve the accuracy of plantation species discriminating at a fine scale.

Objective: In order to control the poplar canker disease by biological control agent,the present study aimed to screen and obtain antagonistic strains from Streptomyces that can effectively inhibit poplar canker. Method: A streptomyces strain with good biocontrol effect against the pathogen of poplar canker was obtained from the soil in the larch forest Hengshan Protection Station,Changbaishan Mountain National Nature Reserve,Jilin Province. The number was recorded as HS1. Multiple screening was used to determine the antibacterial activity of the strain and its fermentation broth; morphological,physiological and biochemical characteristics,16S rDNA sequence analysis were used to determine its taxonomic status; artificial inoculation method was used to determine the preventive and therapeutic effects of HS1 fermentation broth on poplar canker. Result: The result showed that strain HS1 and its fermentation broth had inhibitory effect on the tested plant pathogens,and the antibacterial spectrum was relatively wide. Among them,it had the strongest inhibitory effect on Botryosphaeria dothidea. The width of inhibition zone averagely was more than 20.66 mm and the diameter of the bacteriostatic circle of the fermentation broth reached 40.26 mm.The 16S rDNA sequence alignment analysis showed that the strain had the highest homology with Streptomyces scopuliridis; The result of artificial inoculation test showed that the preventive and therapeutic effects of strain HS1 fermentation broth on poplar canker were 60.87% and 71.74% respectirly. Conclusion: The screened strain HS1 and its fermentation broth could effectively prevent and inhibit the occurrence and expansion of poplar canker disease,and also have a good antibacterial effect on other pathogens of many important agricultural and forest diseases. Therefore,it has a good for development and application prospects in biocontrol of forest pathogens.

Objective: This study investigated the phenotypic plasticity of soil microbial communities in Larix principis-rupprechtii forests in Shanxi Province to reveal the relationship between the structure and phenotype of the microbial community,and the response to environmental heterogeneity,so as to provide a theoretical basis for explaining the mechanism of species coexistence. Method: In Yedoufeng of Wutai Mountain,Pangquangou Nature Reserve of Guandi Mountain,and Luya Mountain,8,10,and 5 samples in the pure forest of Larix principis-rupprechtii were selected along the altitude gradient,respectively. The mixed soil samples of 0-10 cm soil layer in the forests were collected. The composition and structure of soil microbial community were determined by high-throughput sequencing. The change of soil microbial community phenotype was predicted by BugBase analysis. Through statistical analysis of data,the response mechanism of community structure and phenotype to environmental heterogeneity was revealed. Result: The results of this study showed that the large elevation gradients and micro-habitat differences in the Yedoufeng Mountain,Guandi Mountain Pangquangou Nature Reserve,and Luya Mountain led to significant differences in soil chemical properties among the sites. The results of high-throughput sequencing showed that the relative abundance of Proteobacteria was the highest,followed by Acidobacteria,Actinobacteria and Chloroflexi Bacteria. Phenotypic analysis of the floar showed that phenotypes related to oxygen demand (aerobic,anaerobic),biofilm formation and Mobile Element Containing were significantly different in different study sites. In addition,the structure and phenotype of bacterial communities had potential environmental adaptation consistency and similar spatial distribution patterns. Soil pH and organic carbon,total carbon and total nitrogen content had significant effects on soil bacterial community structure and phenotype. Conclusion: The structure and phenotype of the forest microbial community are significantly affected by the physicochemical properties of the soil,and there are great differences among different research sites,but the structure and phenotype of the soil microbial community are consistent in their environmental adaptability,showing a synergistic change law,so that the overall shows a similar biogeographic distribution pattern. Microorganisms can adjust their phenotypes to enhance their adaptability to environmental heterogeneity.

Objective: This study aims to clarify the correlation between shoot blight of Pinus densiflora and plant species in the layer of arbor,shrub and herb,and screen plant species significantly correlated with shoot blight of P. densiflora,so as to provide technical support for controlling shoot blight of P. densiflora through the transformation of plant species composition in the stand. Method: A total of 120 temporary sample plots were set up in the natural secondary forest community of Japanese red pine in Kunyu Mountains to investigate the plant species of arbors,shrubs,herbs and the disease index of shoot blight of P. densiflora. Then the important values of plant species were calculated,and the variance ratio analysis was used to test the correlation between plant species and shoot blight of P. densiflora,and Pearson correlation analysis and Spearman rank correlation analysis were used to quantitatively determine the correlation between disease and plant species. Result: There was a significantly positive correlation between the disease index of P. densiflora shoot blight and the overall association of the neighboring arbors,shrubs and herbs (P < 0.05). Pearson correlation analysis showed that the disease index of P. densiflora shoot blight was significantly or extremely significantly positively correlated with arbors-P. densiflora and P. thunbergii,shrub-Lespedeza bicolor and herbs-Imperata cylindrica,Patrinia scabiosifolia,Sanguisorba applanata,Cocculus orbiculatus,Rubia cordifolia,Belamcanda chinensis,Lysimachia pentapetala,Chrysanthemum indicum,Deyeuxia pyramidalis and Viola philippica (P < 0.05). Whereas there was a significant or extremely significant negative correlation with arbors-Quercus acutissima,Albizia kalkora,Quercus variabilis and Rhus chinensis,shrubs-Deutzia grandiflora and Ampelopsis humulifolia,herbs-Juncus effusus,Arundinella hirta and Adenophora petiolata subsp. hunanensis (P < 0.05). Spearman rank correlation analysis found that the disease of P. densiflora shoot blight was significantly or extremely significantly positively correlated with arbors-P. densiflora and P. thunbergii,shrubs-Lespedeza bicolor and Amorpha fruticosa and herbs-Imperata cylindrica,Patrinia scabiosifolia,Platycodon grandiflorus,Sanguisorba applanata,Cocculus orbiculatus,Rubia cordifolia,Belamcanda chinensis,Lysimachia pentapetala,Chrysanthemum indicum,Deyeuxia pyramidalis and Viola philippica (P < 0.05) , while significantly or extremely significantly negatively correlated with arbors-Quercus acutissima,Albizia kalkora,Quercus variabilis,Sorbus alnifolia and Rhus chinensis,shrubs-Ulmus macrocarpa,Deutzia grandiflora,Ampelopsis humulifolia,Grewia biloba var. parviflora and Cerasus japonica and herbs-Juncus effusus,Cynanchum chinense,Arundinella hirta,Isodon amethystoides,Adenophora petiolata subsp. hunanensis and Commelina communis (P < 0.05). The results of the two analysis methods were partially consistent,with some differences. Relatively,Spearman rank correlation analysis was more sensitive than Pearson correlation analysis. Conclusion: Plant species in the natural secondary forest community P. densiflora in Kunyu Mountains form a stable coexistence state with P. densiflora shoot bligh. Among them,13 plant species are positively correlated with the the disease index of P. densiflora shoot blight and tend to coexist,which can promote the epidemic of P. densiflora shoot blight. And nine plant species are negetively correlated with the disease,and difficult to co-exist with the pathogen,which inhibit the occurrence and development of P. densiflora shoot blight. Therefore,the purpose of ecological regulation of P. densiflora shoot blight can be achieved by adjusting stand structure to reduce plant species that coexist with the pathogen of P. densiflora shoot blight in plant communities,or increase plant species that are difficult to coexist with the pathogen.

Objective: Based on the laboratory simulated experimental data of spotting ignition,Logistic model was used to establish a model of factors influencing the spotting fire ignition,and the applicability of Logistic model in predicting spotting ignition was explored,in order to understand the formation mechanism of spotting fire and provide reference to fire behavior forecast. Method: In this study,Larix gmelinii of Daxing'an mountains,Heilongjiang province was targeted. The cones,1 hour and 10 hours time-lag twigs were used as firebrands. Fuel beds with different wind speed,packing ratios and moisture content of combustible substance were constructed for the ignited experiment. Three Logistic models were established for predicting ignited probability of 3 spotting firebrands. Result: A total of 1 800 ignited experiments were conducted for each firebrand,cone 414 times,1 hour time-lag twig 161 times,and 10 hours time-lag twig 337 times,respectively. In the range of experiment designed,wind speed was positively correlated with ignited probability; fuel moisture content was negatively correlated with ignited probability,but the oven-dry weight of fire firebrand had a great influence on ignited probability. When fuel moisture content was 40%,the larger oven-dry weight of 3 firebrands caused the increase of ignition rate. There was no significant correlation between packing ratio and ignited probability. In cone firebrand model,predicting ignition accuracy rate was 87.2%,total predicted accuracy rate was 71.1%. In 1 hour time-lag twig firebrand model,predicting ignition accuracy rate was 79.6%,total predicted accuracy rate was 78.6%. In 10 hour time-lag twig firebrand mode model,predicting ignition accuracy rate was 81.5%,total predicted accuracy rate was 79.5%. Conclusion: The ignition capability of 3 firebrands is in the order of cone,10-hour time lag twig and 1-hour time lag twig. Wind speed and fuel moisture content and firebrand oven-dry weight have significant effect on ignition. All 3 ignited probability Logistic models have high accuracy rate,and they can be used as a reference for the prediction of spotting fire,in order to improve the efficiency of forest fire fighting and reduce casualties.

Objective: The wooden flume cultural relics unearthed at the Nanyue National Palace site were protected and displayed in situ in the museum. Although the anti-mold treatment was adopted in daily maintenance,recent investigations have found symptoms of suspected mold infestation,and Basidiomycete fruiting bodies were also found on the ground. This research was carried out to study the fungal infection status of wooden flume and analyze the fungal disease information of wooden cultural relics in the in-situ preservation and display environments. Method: Wood samples with typical symptoms from wooden flumes suspected of fungal infection or fruit body were collected,and the technology of traditional tissue isolation and Illumina MiSeq high-throughput sequencing was used to analyze the fungal community diversity information of the samples. Result: 4 wood samples and 1 sample of fruit body from the surrounding soil were collected. 11 species of fungi were isolated from the 4 wood samples classified as ascomycete,with higher rate of Penicillium and Trichoderma. One fungus was identified as Leucocoprinus birnbaumii,classified as basidiomycete from the fruit body. The high-throughput sequencing results showed that the fungal OTUs(operational taxonomic units) contained in the 4 samples were 182,168,213 and 191,respectively,which indicated that the diversity of fungal communities was very rich; 22 species of fungi were detected in all 4 samples,accounting for a relatively high proportion. The dominant species are Exophiala,Aspergillus,Teratosphaeria and L. birnbaumii,with abundances of 16.38%,12.96%,9.27% and 8.54%,respectively. The fruit body isolate L. birnbaumii in the soil was detected in all 4 wood samples,and their abundances were relatively high. Conclusion: The wooden water flume unearthed from the Nanyue National Palace site is still suffering from complex fungal infections in the existing preservation environment. These fungi have a potential risk of disease to wooden cultural relics and human health. Therefore,it is necessary to develop new anti-fungal protectants and new technologies based on the isolated fungi,and to provide further protection measures for the unearthed wooden cultural relics and the healthy environment in the museum.

Objective: Because of the poor sound absorption performance of radiata pine (Pinus radiata),microwave modification was used to improve the sound absorption performance of radiata pine. The influences of different microwave power,treated time and wood grain directions on the sound absorption performance of radiata pine were explored so as to improve the added value of wood and to expand the application field of wood. Method: First of all,the microwave treated wood was obtained by drying the moisture content of radiata pine green wood to 40%-60% in different microwave powers (100 kW,120 kW and 140 kW) and different treated times (20 s and 30 s). Transfer function method was used to measure the sound absorption coefficient (SAC) of microwave treated wood on their radial section and tangential section,in order to discuss the changing rules of the sound absorption performance of radiata pine in varying treated parameters. Optical microscope and scanning electron microscope (SEM) were used to observe the anatomical structure and microwave treated wood microstructure morphology,respectively. Result: Compared with the control samples,the density and moisture content of radiata pine decreased significantly after microwave treatment. The sound absorption performance of radiata pine was improved to different degrees in different microwave treated parameters. The SAC increased about 4.79%-201.9%,and the best average SAC was up to 0.320. The SAC of microwave treated wood under different parameters did not change significantly in the low frequency range below 1 000 Hz. The sound absorption curve showed a trend of first rising and then falling,and the sound absorption trough appeared around 1 000 Hz. The difference of SAC was significant above 1 000 Hz,and the curve of SAC showed an upward trend. The higher the microwave power and the longer the treated time,the better the sound absorption performance of the microwave treated wood,and the higher the trend of the sound absorption coefficient curves. Compared with the radial section sample,the SAC of tangential section of the treated wood was 9.6% to 29.6% higher. When the SAC of the radial section of the control wood was above 1 000 Hz,it was lower than that of the control wood tangential section; when it was below 1 000 Hz,it was higher than tangential section of the control sample. It can be seen that there were a large number of uniseriate rays and a small amount of fusiform rays on the tangential section of radiata pine compared with the radial section by the optical microscope. The microstructure of the microwave treated samples and the control samples was observed by SEM,the results showed that the true middle lamella and the tracheid wall of radiata pine treated by microwave were cracked and pit membrane disappeared,these changes increased the wood porosity and connectivity between adjacent pores,made a greater probable friction between pore wall and sound waves transmitted inside the wood,increased sound energy loss so as to achieve a better sound absorption performance. Variance analysis and partial correlation analysis showed that the correlation among microwave power,treated time and wood grain directions on SAC were 0.519,0.637 and 0.705,respectively. The three variables had a moderate influence on the sound absorption coefficient,among which grain directions had the greatest influence on the sound absorption performance. Conclusion: The SAC of the tangential section and the radial section of the untreated wood was 0.167 and 0.106,respectively,and the sound absorption performance was not very well. Microwave modification could be an effective method to improve the sound-absorbing performance of wood,but it might cause the destruction of wood microstructure. The optimal microwave treatment parameters were 140 kW microwave power,30 s treated time,and the direction of wood grain was tangential section. The SAC of microwave treated wood was up to 0.320,which is known as sound absorption material.

Objective: Studying the hygroscopic behavior and clarifying of the mechanism of water adsorption in Calamus simplicifolius cane are important to provide the theoretical guidance for solving the quality problem caused by water adsorption and desorption in processing and utilization of rattan. Method: In this study, the dynamic vapor sorption apparatus was used to measure the water adsorption behavior of cane. The equilibrium moisture content (EMC) data were nonlinearly fitted by Hailwood-Horrobin (H-H) model, Guggenheim-Anderson-deBoer (GAB) model, Halsey model, Henderson model, Oswin model, and Smith model, and the fitting effects were also evaluated. The optimal fitting models were used to analyze the changes of EMC, monolayer and polylayer water adsorption during sorption processes. Result: The sorption isotherms of C. simplicifolius cane exhibited a sigmoidal shape, belonged to the second category of moisture adsorption isotherms and had the characteristics of multi-molecular layer adsorption. Similar to wood and bamboo, C. simplicifolius cane existed hygroscopic hysteresis, its hysteresis coefficient reached 0.8 at relative humidity (RH) of 80%, which was earlier than that of wood (RH=95%). Among the 6 models, H-H model and GAB model had the highest data fitting degree, with R² both over 0.99. In the H-H model, the parameter W₁, which means the apparent molecular mass of the dry rattan per sorption sites, was significantly less than that of wood and bamboo. In the hygroscopic stage, the adsorption was mainly monolayer water adsorption, and the value was 6.80% at RH < 60%. The water accessible specific surface area (S) and monolayer water adsorption (W₀) in the hygroscopic stage of rattan estimated by GAB model were 293 m²·g^-1 and 7.67%, respectively, which were greater than those of wood and bamboo. The reason might be that the fiber cell wall of rattan was thinner, the cell lumen was larger, the spaces between adjacent parenchyma cells were larger, and the cellulose crystallinity was smaller as well. The fiber saturation point values of rattan were also determined using the GAB and H-H models, which were 20.28% and 18.67%, respectively. Conclusion: The H-H and GAB models could be used to describe the water adsorption isothermal curve of rattan, and provided good fits with the experimental data. The chemical constituent contents, anatomical structure and the cellulose crystallinity were the important factors affecting the adsorption water content of the monolayer, which might result in the adsorption water content of rattan slightly higher than that of bamboo and the effective specific surface area of the cell wall adsorption larger than that of bamboo.

Objective: The purpose of this paper was to study the changes of the number of polar groups and cell wall structure for wood modification, and to clarify the mechanisms of enhancing the dimensional stability of wood modified by in situ copolymerization of water-soluble hydroxyethyl methacrylate (HEMA) and N-hydroxymethylacrylamide (NMA). Method: The polar group lumber and wood surface polarity changes were determinated by dynamic vapour sorption (DVS) and the contact angle using the wood before and after modified with water-soluble vinyl monomers as materials. The distribution of modifier in timber, swelling of cell wall, cell wall two phase variation and the changes of pore structure were in vestigated using scanning electron microscope (SEM), Raman spectroscopy, X-ray diffraction, mercury intrusion method and the nitrogen adsorption system. Result: The equilibrium moisture content of HEMA and NMA modified wood was significantly lower than that of unmodified wood under the condition of 0%-95% relative humidity. When relative humidity reached 95% or above, the equilibrium moisture content of modified woods exceeded that of unmodified woods. The hygroscopic curves of modified and unmodified wood after water soaking were analyzed by H-H model fitting, it was found that the number of polar groups of the modified wood decreased but was not significant. The contact angle test showed that the surface polarity of the modified wood was greater than that of the unmodified wood, but weaker than that of the unmodified wood after the removal of the residual monomer, which indicated that the residual monomer inhibited the improvement of the hydrophobic property of the wood. The cell wall was thickened and intercellular space was decreased by SEM. Raman spectrum analysis showed that the modifier was evenly distributed in the cell wall. Combined with SEM results, it could be found that the modifier entered the cell wall smoothly and moistened the cell wall. X-ray diffraction test showed that no new crystal structure has been found and the crystallinity of modified wood was less than that of the unmodified wood. The results of mercury injection and nitrogen adsorption showed that the porosity of the modified wood was significantly lower than that of the unmodified wood, indicating that the modified agent successfully filled the pores of the cell wall. Conclusion: HEMA and NMA modified wood could effectively improve its dimensional stability. The main reason for improving the dimensional stability of wood might be that the modifier could fully expand and reinforce the cell wall and fill the pores of the cell wall.

Objective: This paper was carried out to explore the adsorption performance of the Pinus massoniana nano-lignocellulose aerogel adsorbent for Cr³⁺/Cu²⁺/Pb²⁺/Ni²⁺, and clarify the related mechanisms of P. massoniana bark and nano-lignocellulose aerogel adsorbing heavy metal ions, with aims to make better use of agricultural and forestry waste P. massoniana bark to prepare low-cost and easy-to-industrial biomass adsorption materials, and to lay a theoretical foundation for its large-scale application. Method: The extracted dry sample was treated with p-toluenesulfonic acid solution for 1 hour under the conditions of heating and stirring in a water bath at 80℃. Then the reaction materials were filtered and filter residue was dialyzed. The filter residue sample was homogenized 20 times by a microfluidizer to obtain nano-lignocellulose samples. The samples with a solid content of 2% were frozen at-20℃ for 120 min, and then freeze-dried to obtain aerogel samples. The adsorption properties of the aerogel were studied, including the maximum q_e of heavy metal ions as Cr³⁺, Cu²⁺, Pb²⁺ and Ni²⁺, the isothermal adsorption characteristics, adsorption thermodynamics and adsorption kinetics. Result: The maximum q_e of different heavy metal ions of Cr³⁺, Cu²⁺, Pb²⁺ and Ni²⁺ were 132.7, 130.4, 186.7 and 123.4 mg·g^-1, respectively. The adsorption of Cr³⁺ on P. massoniana bark nano-lignocellulosic aerogel was consistent with the Temkin isothermal adsorption(R²=0.990 1), and it was a non-uniform monolayer adsorption. The adsorption thermodynamic characteristics indicated that the adsorption process of Cr³⁺ was accordant with the thermodynamic law, with R²=0.992 9. Moreover, the process was a non-spontaneous composite adsorption, and the promotion effects of the increasing temperature on the adsorption process and the inhibition effects of the exothermic reaction on the adsorption process may even cancel each other out. At the same time, the adsorption of Cr³⁺ on the nano-lignocellulosic aerogel of P. massoniana bark was accordant with the pseudo-second-order kinetic model(R²=0.991 0), the adsorption rate of Cr³⁺ was mainly affected by chemical interaction rather than material transport steps, especially the process of chemical sharing or covalent bond exchange between the two. Conclusion: The nano-lignocellulosic aerogel of P. massoniana bark prepared from cheap biomass-mass pine bark can be used as an effective adsorbent for heavy metal ions, showing an ideal adsorption capacity. The conditions involved in static adsorption experiments are also relatively simple. Therefore, it can be experimentally popularized to some extent. The development of the adsorbents can also promote the resource utilization of low-cost biomass. The adsorption performance of P. massoniana bark and nano-lignocellulose aerogel is stable and reliable, and the performance is expected to be improved by optimizing the processes. However, both of the above two points need to test their effectiveness based on large-scale or even pilot-scale experiments, so further to guide the process optimization to obtain better performance of aerogel as a heavy metals ion adsorbent.

Objective: The relationships were explored between caloric values of bamboo charcoal and different species, ages and parts of bamboos under the same carbonization process, calorific values of bamboo charcoal were correlatively analyzed with their ashes, volatiles and fixed carbon contents, and the deduced empirical formula was also applied for calorific values calculation in order to provide guidance and reference for the industrialization and energy utilization of bamboo wood. Method: The calorific values of bamboo charcoals carbonized from various bamboo species were taken as the objects of this study. 24 bamboo species grown in Lin'an, Zhejiang Province, and 2-to 13-year-old moso bamboo grown in Anji, Zhejiang Province, were collected and carbonized under the same process. Applying the single-factor-control method, the calorific values and proximate analysis of bamboo charcoals which were carbonized by middle parts of 24 bamboo species and moso bamboos(2-13 years), and top, middle and base parts of 4-, 5-, 6-year-old moso bamboos were tested, respectively. The effects of species, ages and parts of bamboo on the calorific value and fixed carbon, volatile, ash content were studied. Test data were summarized to find whether the calorific value was significantly correlated with fixed carbon, volatile and ash content by SPSS software. The empirical formula was deduced based on the relationships between the carbonization temperature(T), calorific value(Q) and fixed carbon(C). Result: The calorific values of 24 kinds of bamboo charcoal were distributed in the range of 27.94-32.98 kJ·g^-1, the mean value was 31.10 kJ·g^-1, the standard deviation was 1.11; the fixed carbon content was 75.35%-92.59%, the mean value was 85.87%, and the standard deviation was 3.65; the ash content was 3.34%-15.98%, the mean value was 7.21%, and the average volatile content was 6.91%. The calorific value of the charcoal produced from 2-to 13-year-old bamboo was distributed in the range of 30.93-33.81 kJ·g^-1, and the standard deviation of the fixed carbon content, ash content and volatile content were all less than 5, respectively. For 4-, 5- and 6-year-old bamboo carbonized materials, the absolute difference of calorific value of each part was below 1.38 kJ·g^-1, and the relative difference was under 3%. The high calorific value of bamboo charcoal was positively correlated with fixed carbon content, but negatively correlated with ash content. According to the relationships between the carbonization temperature, calorific value and fixed carbon of bamboo charcoal, the deduced empirical formulas were as follows: Q=0.001 8C²-0.111C+28.099(R²=0.72), C=26.934lnT-93.122(R²=0.88). Conclusion: 1) The diversity exists between calorific value and proximate analysis of bamboo charcoals carbonized from different bamboo species, which depends on the structural characteristics of bamboo species. The calorific value of carbonized materials of the same bamboo species at the base is higher than that at the middle and top parts, which is attributed to the higher lignin content at the base. In addition, bamboo ages and growth parts have no significant influences on calorific value and proximate analysis. 2) There is a linear relationship between the calorific value of bamboo charcoal and the fixed carbon and ash content, of which the calorific value is positively correlated with fixed carbon content and negatively correlated with ash content. The deduced empirical formulas Q=0.001 8C²-0.111C+28.099(R²=0.72) and C=26.934lnT-93.122(R²=0.88).

Objective: With the rising labor cost in rural China, the structure of commercial forests displays a phenomenon of "tending to become economic forests". This is contrary to the feature of "tending to become grains" in agricultural sector. This study aims to explain the unexpected phenomenon from the perspectives of labor cost and relative revenue, in order to understand the underlying mechanisms of farmers' decision-making on forest structure adjustment, and to predict the trend of structure adjustment of commercial forests. Method: From the perspectives of labor cost and relative revenue, this study establishes a logical framework for the adjustment of structure of farmer's commercial forests. Based on this, several hypotheses are proposed, and the empirical analysis is performed based on a household survey dataset from National Forestry and Grassland Administration, which covers 9 provinces in China. Considering the censoring of data and the endogeneity of variables, this study adopts the Ⅳ-Tobit to estimate parameters. Result: The ratio of economic forests has increased from 11% in 2003 to 19% in 2013, and shows a significant rise before and after the collective forestland tenure reform. It displays an evident trend of "tending to become economic forests". The statistical descriptions show that the revenue per hm² of economic forests is around 2.15 times of that of timber forests. The estimation with Ⅳ-Tobit model shows that there is a positive and negative effect of labor cost and relative revenue on the structure of commercial forests. The effect of labor cost is significant at the 5% level, and the effect of relative revenue is significant at the 1% level. This reflects that the structure of commercial forests is affected by both labor cost and relative revenue, and the adjustment direction depends on the intensities of the two effects. In addition, the interaction coefficient between collective forestland tenure reform and relative revenue is positive and significant at the 1% level. It shows that the positive effect of relative revenue on economic forests is strengthened after the collective forestland tenure reform, i.e., the positive effect is moderated by the tenure reform. A further calculation shows that, the contribution rate of labor cost is about-26%, while the rates of relative revenue and the interaction are about 41% and 28% respectively. It implies that the positive effect of relative revenue is dominant, which leads to the increase of the proportion of economic forest area. Furthermore, the regression with previous four years verify the hypotheses from an opposite perspective. The robust tests show that the above results are basically robust. Conclusion: Rising labor cost lead to a decline of the proportion of economic forest area; but the moderating effect of collective forestland tenure reform has strengthened the positive effect of relative revenue on the proportion of economic forest area. This leads to the "tending to become economic forest" of the structure of commercial forests. The inter-sector difference on property rights reform is an important reason for the opposite adjustment trend of the agricultural and forest structure. These findings are helpful for the prediction of the future trend of commercial forest structure and have insightful policy implications on the optimizing of commercial forest structure.

Objective: The decline and even death of vegetation caused by drought are not limited to arid areas. Species growing in humid areas have weak adaptation to drought, and thus are more likely to die from hydraulic failure. Establishing quantitative relationship between xylem anatomy and hydraulic function(including hydraulic efficiency and safety) at organ level of vascular plants is the key to understand the drought-induced mortality mechanism for plants growing in humid areas. Method: Pinus massoniana, P. parviflora and P. elliottii were sampled to determine the hydraulic function(hydraulic conductivity, embolism resistance) and anatomical structures(tracheid traits, pit traits, etc.) of branch and root xylem. Combined with data from published studies, the trade-offs between hydraulic efficiency and hydraulic safety of branch and root for Pinus were examined; And the structural basis of xylem hydraulic efficiency(K_s, sapwood-specific hydraulic conductivity) and embolism resistance(P₅₀, xylem water potential causing 50% loss of hydraulic conductivity) were analyzed quantitatively. Result: 1) For the three Pinus species, K_sr(root K_s) > K_ss(branch K_s), root P₅₀ > branch P₅₀; K_ss was positively correlated with K_sr, branch P₅₀ and root P₅₀ were also positively correlated; All the three species showed low efficiency and low safety. 2) Correlation analysis revealed that: K_ss was negatively correlated with branch P₅₀, branch exhibited an efficiency-safety trade-off. The correlation coefficient between K_sr and root P₅₀ was close to 0(R²=0.01, P=0.94), there was no trade-off in root. Functional trade-off was determined by anatomical structure: K_ss and branch P₅₀ had different structural requirements(there was an efficiency-safety trade-off in branch), while K_sr and root P₅₀ had similar structural requirements(there was no trade-off in root). 3) Redundancy analysis revealed that: K_ss was best interpreted by branch pit membrane area; Branch pit torus area had the highest interpretation for branch P₅₀; K_sr was best interpreted by root wood density; Root pit margo area had the highest interpretation to root P₅₀. Conclusion: Hydraulic efficiency and embolism resistance of branch and root were mainly determined by anatomical structure, of which pit had the greatest influence, followed by wood density and tracheid wall thickness. This study demonstrated that there was an efficiency-safety trade-off in branch, but not in root. The anatomical structural bases behind this are: If the structural requirements are different, there is a trade-off between efficiency and safety, while the structural requirements are similar, then no trade-off.