[Objective] This study aims to explore the dynamic changes of the diversity and interspecific relationships of vegetation communities in Caijiachuan small watershed, located in Loess Plateau in western Shanxi Province which has been closed for 35 years. The findings of this study will provide a theoretical basis and technical supports for the closed-to-nature restoration and reconstruction vegetation in the Loess Plateau.[Method] In July and August, 2016, both line transect and quadrate sampling methods were employed to survey the status vegetation in six different habitats (including sunny slope, semi-sunny slope, shady slope, semi-shady slope, hilltop and ditch sole) in the small watershed. The survey data was compared with those obtained in 1996 (closed for 15 years), 2007 (closed for 26 years),and 2016 (closed for 35 years). The dynamic changes of the diversity and interspecific relationships of vegetation communities were analyzed by comparing indices in the periods from 1996 to 2007 (considered as the first period) and from 2007 to 2016 (considered as the second period).[Result] On a time scale, the Jaccard index, which indicates the degree of similarity, increased significantly in each of the six habitats in the second period. The increase in the habitats of semi-sunny slope, sunny slope, semi-shady slope, shady slope, hilltop and valley bottom were 69.6%, 27.3%, 18.1%, 48.5%, 5.2%,and 1.0% respectively. The Cody index, which indicates the degree of species replacement, decreased in almost all of the six habitats except the hilltop, where it was kept the same in both the first and second periods. The decrease in habitats of semi-sunny slope, sunny slope, semi-shady slope, shady slope, and valley bottom were respectively 41.2%, 29.4%, 28.6%, 50.0%, and 22.7%. In 2016, the Jaccard index of habitat gradient was in an order of shady slope-semi shady slope > sunny slope-semi sunny slope > valley bottom-shady slope, while the Cody index of habitat gradient of shady slope-semi-shady slope=sunny slope-semi-sunny slope < hilltop-sunny slope. The interspecific relationships of vegetation community in the semi-sunny slope in 1996 were not significantly related with that in 2007 (P> 0.05). Similar phenomenon also happened in the sunny slope and the valley habitat. However, significant positive correlations (0.01<P<0.05) of the interspecific relationships of vegetation community were found between 1996 and 2007 for the other three habitats. The interspecific relationships of vegetation community in the valley bottom in 2007 was significantly positively related with that in 2016 (0.01 < P < 0.05). While, extremely significant positive correlations (P < 0.01) were found between 2007 and 2016 for the other habitats. The association coefficient (AC) representing the junction strength between communities of the hilltop habitat was decreased in the second period compared with the first one. While, the AC of the other five habitats increased significantly.[Conclusion] The improved rate of vegetation abundance in the closed small watershed in the second period from 2007 to 2016 was slower than that of the first period from 1996 to 2007. The community similarity between the shade slope and semi-shady slope were increasing, and the rate of species replacement was slowing down. The same situation existed on the sunny slope and semi-sunny slope. For long run, there was a certain correlation between vegetation communities in the same habitat, and the structure of the communities gradually turned to be stable, even though they might still be the stage of progressive succession.

[Objective] This paper intends to provide a new method of quantitative evaluation of forest ecosystem service of temperature regulation. This method builds up value calculation of insulation in winter and provides a basis for correct understanding and quantitative assessment of forest ecological service value.[Method] The forests in Shandong Province were studied using MODIS derived LST (land surface temperature)product, land cover product to calculate the energy convert to temperature difference of atmosphere near the ground between forest and other surface type to evaluate the service value of temperature regulation function of forest.[Result] The result showed that the effect of regulating temperature by forest mainly behavior during the daytime instead of night. The cooling function in summer is more significant than heat preservation function in winter. The total value of temperature regulation function of daytime in summer and winter of 2012 was about 100.4 billion RMB in Shandong Province. The value product in summer by cooling function is about 10 times in winter which product by heat preservation function.[Conclusion] The new method to calculate forest ecosystem service of temperature regulation based on thermal infrared remote sensing and energy balance can calculate the value of temperature regulation of forest in any period. This method makes up the calculation of forest heat preservation in winter and takes the spatial differentiation into consideration. This method has significant implications for quantitative assessment of forest ecosystem service value and function of ecological service.

[Objective] To analyze the influence of environmental factors on total soil respiration rate (R_s) and heterotrophic respiration rate (R_h) and their seasonal dynamics of burned forest area in the subalpine regions in western Sichuan, China. By comparing the rate of R_s and R_h between burned area and control plot (CK), the results would provide a basis for comprehending the forest carbon cycle and estimation of soil C fluxes under the condition of fire disturbance.[Method] In this study,the burned area (8 years since fire) Quercus aquifolioides and control plots (CK) of subalpine forest in Western Sichuan were studied. Using a field setup through root exclusion method and LI-8100 automated soil CO₂ flux system, we measured R_s and R_h, soil temperature (T₅) and soil gravimetric water content (W₅) at 5 cm depth from September 2010 to December 2011. Relationships of R_s and R_h with abiotic factors were determined by fitting both an exponential model and a two-factor model.[Result] In dormant season, R_s and R_h rates for the burned area were obviously higher than those of control plot (P < 0.05), respectively. However, R_s and R_h were not different between the burned area and the control plot in growing season and whole year (P > 0.05). A significant exponential relationship was found between R_s or R_h and T₅ in different seasons, respectively (P < 0.01). There was a significant relationship between R_s or R_h and W₅, but no significant effect was observed of W₅ on R_s or R_h in the CK plot during growing season. We found that R_s or R_h appeared to be a inhibition phenomenon by W₅ when it was low than 25.8%, but there was no significant relationship when it was over 37.7% (P > 0.05). Notably, T₅ and W₅ two-way model was better than the single factor model. Therefore, soil carbon emission was significantly affected by T₅ and W₅ in the subalpine forest. Furthermore, the soil temperature sensitivity (Q₁₀) values of Rs and Rh from the burned area were lower than those of in the CK plot, whereas Rs are more sensitive to T₅ in different seasons. Moreover, R_s and R_h of burned area and CK were strongly correlated to nitrate nitrogen, light fraction organic carbon and particulate organic carbon at 0-30 cm soil layers. The estimated values of R_s and R_h for burned area was 13.9% and 1.8% higher than those for control plot.[Conclusion] Our study indicated that R_s and R_h were dominated by interaction of T₅ and W₅.We can infer that soil carbon emission of burned area may be less sensitive to temperature variations than the CK under global warming scenarios. Our results emphasize that fire disturbance in forest land and associated carbon metabolisms should be taken into consideration in the model construction under climate change scenarios.

[Objective] In order to provide a theoretical basis for effective conservation and rational utilization of Amygdalus mira resources in Tibet, genetic diversity and population structure of 21 populations of A. mira were studied using SSR markers, and correlation between genetic structure and geographical distribution, altitudinal gradient were also analyzed.[Method] A total of 420 individuals from 21 populations were assayed by 25 pairs of SSR primers. Genetic diversity parameters, principal coordinates analysis (PCoA), and analysis of molecular variance (AMOVA) were carried out using GenAIEx 6.5 and Arlequin v3.1 software. NTSYS software was used for cluster analysis based on the matrix of Nei's genetic distance. STRUCTURE, STRUCTURE Harvester, CLUMP, and Distruct software were used to analyze genetic structure.[Result] Result showed that both genetic diversity and inbreeding were moderate within A. mira populations. The average number of alleles, effective number of alleles, expected heterozygosity, observed heterozygosity, Shannon's information index, and inbreeding coefficient were 3.8, 2.5, 0.52, 0.44, 0.95, and 0.17, respectively. The highest level of genetic diversity was in the P17 population (N_e=4.7, H_e=0.63, H_o=0.56, and I=1.57), while the lowest was in the P18 population (N_e=1.7, H_e=0.30, H_o=0.22, and I=0.49). According to STRUCTURE, Principal coordinates analysis (PCoA) and UPGMA cluster analysis, 420 individuals could be divided into three genetic clusters, which were significantly correlated with geographic altitudes. Mantel test showed that the genetic distance among the populations was significantly correlated with geographic distance (r=0.50, P<0.01) and geographic altitude (r=0.61, P < 0.01). AMOVA analysis showed that 16.3% genetic variation was among the populations, which indicate that the level of genetic differentiation among population is moderate, while, a high genetic variation (83.7%) was within populations.[Conclusion] It was suggested that the genetic diversity of A. mira in Tibet plate was moderate. The impact of geographical isolation and elevation gradients on genetic diversity was shown within populations. The degree of genetic differentiation was high, which could be due to the habitat fragmentation, elevation gradient, and the mountains block that caused by the effect of geographical isolation. The natural resources of A. mira in Tibet was seriously disturbed by human activities, and inbreeding among individuals was frequent. Therefore, the genetic diversity will gradually decrease if protection measures are not taken in time. Based on the genetic structure analysis, three protection units of A. mira in Tibet have been determined, and the human activities should be prevented. We suggest that it be conserved in situ and the exchange of genes between different groups should be promoted to protect the genetic diversity of A. mira in Tibet.

[Objective] Core collection of Eucommia ulmoides was constructed to retrench germplasm resources in the gene pool, which will provide a theoretical basis for protecting, utilizing and studying germplasm resources of E. ulmoides.[Method] Based on allele number maximization strategy,core collection of E. ulmoides was constructed from 887 total collections, which located in 54 distribution area, by using nine SSR primers and bioinformatics software. Core collection of E. ulmoides was assessed by the number of allele (n), average number of allele(N_a), average effective number of allele (N_e), average Shannon's information index (I), Nei's diversity index (H), average genotype number (N_g), average polymorphism information content (PIC), and their retaining ratio. The representative of the core collection to the total collection was confirmed with t-test and PCoA analysis.[Result] 107 alleles(n) were detected in 9 SSR primer pairs, the average of N_e was 5.096. High genetic diversity was revealed in the germplasm resources of E. ulmoides(I=1.812, H=0.925). 189 of 887 core collections were obtained based on allele number maximization strategy, suggesting that the 21.3% of the collection samples contained 100%number of alleles. The retaining ratio of N_a, N_e, I,H, N_g and PIC of nine SSR locus was 100%, 116.5%, 108.7%, 101.5%, 100%, 103.3%, respectively. t-test analysis suggested that there was no significant correlation between the six evaluation parameters of core collection and total collection. This result was further confirmed by the PCoA analysis. 698 of 887 reserve collections were obtained based on allele number maximization strategy, suggesting that the 78.7% of the collection samples contained 86.9% number of allele. The retaining ratio of N_a, N_e, I, H, N_g and PIC of the nine SSR locus was 86.9%, 95.7%, 96.7%, 99.4%, 77%, 99%, respectively. t-test analysis suggested that there was no significant correlation between the six evaluation parameters of reserve collection and total collection.[Conclusion] The core collection of E. ulmoides was well constructed, which contained all the alleles and genotypes. There was no significant difference in six evaluation parameters of the core collection and total collection. Moreover, the core collection and total collection samples had the similar structure in the distribution map. All the seven evaluation parameters of the core collection were higher than the reserve collection. Therefore, the core collection should be priority option in protecting germplasm resources and constructing breeding population of E. ulmoides. This study laid a foundation for the identification of favorable genes and breeding of new varieties of E. ulmoides.

[Objective] WUSCHEL-related homeobox (WOX) is a class of plant specific transcription factors. They play important roles in plant growth and development including stem cells maintaining, lateral organs development, de novo root regeneration of the explant, and other development processes. In this study, the expression patterns and phenotypic traits were analyzed to explore the gene function of PtoWOX4a and also to provide a basis for comprehensive research on the mechanism of WOX genes in different species.[Method] The relative expression of PtoWOX4a in shoot apical meristem, young leaf, mature leaf, tender stem, old stem, phloem, xylem and root in Populus tomentosa were analyzed by qRT-PCR. GUS staining was further analyzed the expression patterns of PtoWOX4a in different tissues. The genetic effects of PtoWOX4a on plant development were explored by studying adventitious root (AR), stem and leaf morphology and histological anatomy structure in the PtoWOX4a overexpression poplar.[Result] qRT-PCR result showed that the highest accumulation of PtoWOX4a transcripts was observed in stem, followed by root and leaf. The result of GUS staining was consistent with the qRT-PCR result, revealing that PtoWOX4a was mainly expressed in the vascular tissue of AR, leaf and stem. In 3-week-old seedlings, overexpression of PtoWOX4a shortened the AR length to 3-4 cm, which was only 1/3-1/2 compared with the control; overexpression of PtoWOX4a increased AR diameter and promoted xylem cell differentiation in AR. In 3-month-old plants, the overexpression of PtoWOX4a transgenic plants showed dwarf phenotype. Compared with the control, they exhibited 14%-20% decrease in stem height, 16%-22% decrease in internode number. In the tenth internode, the transgenic plants showed 10%-20% decrease in the width of pith parenchyma cells, 24%-35% increase in the width of xylem, but the width of cambium did not change significantly. Furthermore, overexpression of PtoWOX4a caused the upward leaf curling.[Conclusion] PtoWOX4a mainly expresses in the vascular tissue of poplar. Overexpression of PtoWOX4a affects the development of vascular tissues of poplar root, leaf and stem.

[Objective] In order to ascertain the physiological mechanism of Si-alleviated Pb toxicity in the Salix viminalis and provide theoretical basis for the Si treatment in heavy metals contaminated soil, it was analyzed the effect of Si on Pb distribution and transport under Pb stress, membrane lipid peroxidation and osmoregulation response to Pb stress in the S. viminalis.[Method] With the disposal method of applying Si after Pb stress, Pb concentration was set two levels including 0, 1.8 mmol·L^-1; Si concentration was set three levels including 0, 1.5, 5.0 mmol·L^-1. It had four blocks and each block was set six treatments. A sand culture experiment was conducted to study the regulation and control effect of Si on growth, Pb distribution and transport, membrane lipid peroxidation and osmoregulation of S. viminalis under Pb stress.[Result] Pb stress could significantly decrease the relative height and ground diameter growth rate, increase the relative electrical conductivity, O₂^·-producing rate, MDA content, pro and sp contents of the S. viminalis leaf and root. Compared with Pb treatment, by using 1.5 mmol·L^-1 Si after Pb stress, Si reduced the relative electrical conductivity, leaf O₂^·-producing rate, MDA content and the pro content of the S. viminalis root, increased the relative height and ground diameter growth rate. Simultaneously, Si significantly reduced the content by 90.92% on the ground of the S. viminalis, which increased the Pb content by 63.93% in the root of it, and the total Pb content by 43.36% in the S. viminalis. Using 5.0 mmol·L^-1 Si after Pb stress, it had no significant influence to relieve Pb stress. On the one hand, Si concentration might be too high; on the other hand, it might be that the adsorption of mineral elements and buffering capacity in sand are less than in soil.[Conclusion] By analyzing several aspects of growth index, membrane lipid peroxidation and the Pb distribution and transport for Si regulation under Pb stress in the S. viminalis, it showed that Pb inhibited the growth and caused membrane lipid peroxidation of the S. viminalis. Si alleviated Pb toxicity by reducing membrane lipid peroxidation and decreasing Pb transfer from the root to the shoot of the S. viminalis. Besides, that Si improved the total Pb in the S. viminalis and inhibited Pb release to the outside. These characteristics provided theoretical basis for the Si treatment in heavy metals contaminated soil. This study is a sand culture experiment, the adsorption and diffusion barrier effects in gravel are different from that in soil. So, Si concentration, whose reaction in different plants and soil conditions is different. Therefore, it needs further research and practice in the Si treatment of heavy metal contaminated soil.

[Objective] In order to meet the urgent needs of national forest inventory (NFI) for monitoring national forest resources on a macro-scale, an object-oriented regional land cover classification method was developed in this paper by using permanent forest plot data of NFI and integrating the corresponding spatial and temporal resolution advantages of GF-1 WFV multi-spectral data and MODIS remote sensing data.[Method] The test site is located in the central of the Xiaoxing'an mountain region in Heilongjiang Province. The GF-1 WFV multispectral data, time series MODIS NDVI product of 8 days synthetic (250 m spatial resolution), the permanent forest plot data collected by the NFI and some field survey data are employed as the key data sources. After image segmentation, spectral, texture and shape features from GF-1 WFV multi-spectral data and NDVI features from times series MODIS NDVI data are extracted for each object. Based on these features, the random forests algorithm is adopt to select the best features automatically and then the classification and regression tree is used to administer the supervised classification. The permanent forest plot data are used to build and validate the decision tree classifier. This method has been investigated with the data collected for the study site.[Result] Experimental results show that the overall accuracy and Kappa coefficient of the developed method combing multi-sources data can reach 89.46% and 0.874 respectively, with significant improvement compared with that using either GF-1 WFV multi-spectral data or MODIS NDVI time series data alone.[Conclusion] The land cover classification method developed in this study is appropriate for integrating GF-1 data and GF-4 data for land cover classification mapping and can improve accuracy of land cover classification effectively.Compared with existed research work,this paper has developed one land cover classification method of much more practical application value with some special features such as focusing on the operational application needs and the characteristics of NFI,optimizing the key procedures such as classification objects generation,feature extraction,feature selection,classifier training,accuracy validation,and so on.The land cover classification method developed is useful for improving the automation and standardization of the technique flow to produce forest land cover maps implemented by NFI.

[Objective] In order to provide a scientific basis for below-ground biomass estimation at stand level, heavy sample and second sample were used, below-ground biomass equations were constructed and fitted to compare the effect of sampling forms on the individual tree biomass equations. In the main distribution area of Chinese fir(Cunninghamia lanceolata), the study on expanding below-ground biomass from individual tree to regional scale was conducted and the advantage and disadvantage of the different forms of below-ground biomass equations at stand level was explored.[Method] 278 trees of Chinese fir(C. lanceolata) with measured above-ground biomass were taken as a heavy sample, 88 trees of which with measured below-ground biomass as second sample. The models at individual level included single independent model, the simultaneous equations compatible with above-ground biomass, which only used second sample, and the simultaneous equations compatible with above-ground biomass, which combines a heavy sample and second sample. Choosing the below-ground biomass equation based on stand description factors, fixed root-shoot ratio equation and the root-shoot ratio equation based on stand description factors, the expansion method from tree level to regional scale on below-ground biomass were studied in Fujian, Jiangxi and Guangdong provinces. Coefficient of determination(R²), root mean square error(RMSE), average system error(ASE), relatively mean absolute error(RMA),relatively total error(TRE)and mean prediction error(MPE) were used to evaluate the model fitness. The model parameters in different provinces were compared and the relationship between stability of parameter estimates and sample size were analyzed. Meanwhile, parameter estimates were also compared with the root-shoot ratios recommended by IPCC.[Result] All three types of individual tree equations basically performed the same efficiency with R² reaching to 0.95,the compatible equation combing a heavy sample and second sample performed best. The root-shoot ratio equation based on stand description factors had a significantly better fitting than the fixed root-shoot ratio equation(R² improved 0.04-0.08, RMSE reduced 1 t·hm^-2) when expanding to regional scale. The below-ground biomass equation based on stand description factors performed better than the fixed root-shoot ratio equation but inferior to the root-shoot ratio equation based on stand description factors. The prediction error had geography diversity and the same method on predicting error in different provinces failed to give a consistent law.[Conclusion] Combining a heavy sample and second sample contributes to model fitting at tree level. Adding stand description factors into below-ground biomass stand model significantly increases model fitness. As the form of fixed root-shoot ratio equation is sample, it could be conveniently used to conduct below-ground biomass expansion. The research result contribute to the selection and establishment of the best individual tree below-ground biomass equation, and provide an accurate and scientific method for tree-level biomass expansion to regional scale.

[Objective] Based on allometric model, individual tree volume model was developed for Larix gmelinii and Pinus sylvestris var. mongolica in Daxing'anling. Error structure and variance function were studied.[Method] Ballantyne(2013)provides the method how to test the error structure by likelihood analysis. For comparison, nonlinear model was fitted using GNLS in S-PLUS. Variance functions (fixed variance, exponential function, power function and constant plus power function) were incorporated into general nonlinear model to reduce heteroscedasticity. Coefficient determination (R²), root mean square error (RMSE), mean absolute bias (Bias), and mean relative error (MRE), were employed to evaluate the precision of different individual volume models.[Result] 1) Through likelihood analysis, error structure of individual tree volume model is multiplicative, therefore, linear regression on the log-transformed data is suitable for individual tree volume model. 2) In order to describe the variance phenomenon in the process of individual tree volume model, variance functions (fixed variance, exponential function, power function and constant plus power function) were incorporated into volume model,and all variance functions could reduce heteroscedasticity, power function and constant plus power function are best for Larix gmelinii and Pinus sylvestris var. mongolica respectively. 3) Model fitting and validation indicated that the result were pretty similar for both error structures of this two species, however, volume model with additive error structure is slightly better than multiplicative error structure.[Conclusion] Error structures of individual tree volume model are multiplicative for this two species. However, through the comparison of model fitting and validation, nonlinear regression is better than linear regression on the log-transformed data. This study did not give an absolute and consistent conclusion from comparison. If model prediction is the first, error structure should be selected based on prediction precision. In summary, additive error structure was favored for individual tree volume model of Larix gmelinii and Pinus sylvestris var. mongolica.

[Objective] The purpose of this paper was to investigate characteristics of the soil fungal diversities and community structures in dry and wet seasons under different waterlogging conditions in Napahai plateau wetland, in order to provide data support for understanding the ecological mechanisms of soil microbial during the process of plateau wetland degradation and provide data and theoretical basis for the protection and restoration of plateau wetland.[Method] Three typical wetlands (swamp wetland with perennial waterlogging SWPW, swamp meadow with seasonal waterlogging SMSW and meadow without waterlogging MW) under different waterlogging conditions in Napahai wetland were targeted. We used high-throughput sequencing technology to study dynamic characteristics of soil fungi community in dry and wet seasons, and we applied RDA analysis to explore effects of soil physical and chemical properties on soil fungal diversities and community structures caused by different water conditions.[Result] 1) We found soil fungi totally 54 genera in 29 classes and 5 phylum of soil fungi by high-throughput sequencing, and waterlogging conditions significantly influenced the composition and structure of soil fungi. With the decrease in waterlogging condition of the wetland soil, the soil fungi composition shifted from unclassified fungi to Ascomycota, the abundance of unclassified fungi decreased from 85.26% and 66.27% to 5.63% and 6.43% in dry season and wet season, respectively, while the abundance of Ascomycota increased from 9.9% and 10.57% to 71.11% and 52.07%, respectively. From the dry season to the wet season, unclassified fungi decreased and classified fungi increased in Napahai, with the dominant fungi classes increased from 6 to 8. 2) There was a significant difference in fungi community diversity between different waterlogging conditions (P<0.05) and between dry and wet seasons (P<0.05). The diversity of MW was significantly higher than that of SWPW and SMSW, and higher diversity was presented in the wet season than in the dry season, particularly for SMSW. 3) Waterlogging conditions significantly affected soil physical and chemical properties of plateau wetland (P<0.05). In both dry and wet seasons, soil organic matter, TN, water content, AN, and TK were featured with the tendency of the highest portion in the SWPW, seconded by that in SMSW, and the lowest in MW, and content of those substance were higher in the wet season than that in the dry season.4) RDA and Pearson correlation analysis showed that water content, organic matter, TN and AN and TK were the main factors that significantly influenced soil fungi community structures in dry and wet seasons under different waterlogging conditions.[Conclusion] Wetland hydrological changes caused by drainage significantly changed the wetland soil physical and chemical properties, which led to changes in the composition, structure and diversity of soil fungi. The results would provide scientific evidence for the study of soil microbial structure and its ecological process in the degraded plateau wetland.

[Objective] The broad-leaved Korean pine forests were typical zonal forest community in eastern forest areas in northeast China, with high biological diversity. In this paper, we systematically investigated species composition and diversity of ground-dwelling beetles in the different stands of broad-leaved Korean pine forests, and revealed the influence of stand types and stand factors on diversity of ground-dwelling beetles, in order to evaluate the role of natural forests in the protection of ground-dwelling beetles, and provide a scientific basis for the formulation of forest management plans based on the protection and utilization of the ground-dwelling beetles.[Method] In the active period of ground-dwelling beetles during 2012 and 2013, the beetles were traped by using pitfall traps at four stands in Jiaohe district, Jilin Province. The influences of stand types and stand factors, including canopy density, stand age, litter thickness, herb coverage, stems per hectare, and shrub coverage, on the diversity of the beetles were analyzed.[Result] Totally 9 849 specimens of ground-dwelling beetles were catched and they belong to 79 species of 22 families. The dominant groups included Carabidae, Silphidae and Staphylinidae, in which Pterostichus acutiden (Coleoptera:Carabidae) was the most dominant species. Species compositions of the ground-dwelling beetles were different in different stands. Their diversity was higher in the broad-leaved Korean pine forests (A and B) than the poplar-birch forest and the ash-walnut forest. It was showed that there was a significant negative correlation between individual and evenness of ground-dwelling beetles, and the similarity coefficient was highest between broad-leaved Korean pine forest A and broad-leaved Korean pine forest B. The individual number of Carabidae, Silphidae, Staphylinidae was significantly different in different stands. It was significantly greater in the broad-leaved Korean pine forest (A and B) in than the poplar-birch forest and ash-walnut forest. Carabidae had slightly higher adaptive capacity to the poplar-birch forest than Silphidae and Staphylinidae, and there was a strong correlation in the individual number between Carabidae and Staphylinidae in different stands, with the linear model Y=89.68+3.241x.[Conclusion] The composition and structure of the stand directly affected the internal ecological environment and related factors. The different stand factors had different effects on each group of ground-dwelling beetles. Canopy density, stand age, litter depth had a strong positive influence on the individual number of Silphidae, herb coverage, stems per hectare, shrub coverage had a small influence on the individual number of Carabidae, and the stand factors had a weak influence on the individual number of Staphylinidae. In this study, the stand structure and age were different with less human disturbance, thus a stable internal ecological environment was formed in the process of long-term growth, and the environment influenced survival and reproduction of ground-dwelling beetles as well. The composition of the broad-leaved Korean pine forest (A and B) was complex, and the internal ecological environment was favorable for the survival of ground-dwelling beetles with relative abundant rare species. Therefore it played a more important role in protecting the diversity of ground-dwelling beetle.

[Objective] This study was to observe the trends of chemical signals when the different resistant individuals of Pinus massoniana had been inoculated with pine wood nematodes, in order to provide the theoretic support for clarifying the resistant mechanism of infected trees of P. massoniana.[Method] The high resistant and susceptible clones had been selected following a serious of breeding produce. The dynamic variation of signal moleculars including H₂O₂, O₂^-·, NO and Ca²⁺ was detected in needles of different resistant clones at 1, 3, 7, 15 and 30 d post inoculation (dpi).[Result] The results showed that a large number of pine wood nematodes were detected in different parts of susceptible clones, while no nematodes were found in the high resistant clones. The H₂O₂ content significantly increased in different resistant clones at 1, 3 and 7 dpi. The H₂O₂ content in high resistant ones was returned to the health level after 15 dpi but the susceptible ones rose sustainably. As a result, the H₂O₂ content in susceptible clones was 1.77 times higher than that in resistant ones. The O₂^-· content also significantly increased in both resistant and susceptible clones during 1 to 15 dpi. They had a same trends and no significantly differences. The high resistant clones reduced the O₂^-· content at 30 dpi but the susceptible ones still increased it. There was no significant difference in NO content between high resistant clones and the control group during 1 to 15 dpi. It was significantly higher than control group at 30 dpi. However, the NO content in susceptible ones was significantly higher than that of the control group and high resistant ones at each time point. The variation trend of Ca²⁺ content was similar between different resistant clones post inoculation. They both performed in an up-down-up-down trend. The Ca²⁺ content of high resistant clones was significantly higher than that of control group and susceptible ones at 1 dpi and 15 dpi. However, the Ca²⁺ content of high resistant clones maintained at an ordinary level at the other time points. The Ca²⁺ content of susceptible clones was significantly higher than that of control group at each point.[Conclusion] The content of H₂O₂, O₂^-· and Ca²⁺ would increase rapidly when the pines were invaded by nematode. They could induce defensive response as signal moleculars. The high resistant clones had an effective way to control signal molecular content and finally returned to normal physiological metabolism. However, the susceptible ones could not control and the excessive ROS and Ca²⁺ would damage the plants. NO content was stable in the high resistant clones post inoculation. But it was accumulated at each time point in susceptible ones. The redundant NO is harmful for P. massoniana metabolism.

Cephalcia infumata Zhang & Wei, sp. nov., a new species of Pamphiliidae (Hymenoptera) defoliating Picea crassifolia Kom.was collected from Helanshan Mountains, Inner Mongolia, China. The new species is similar to Cephalcia alashanica and C. masuttii. The larvae of the three species make conspicuous nests with silk and dung on the twigs. The new species differs from Cephalcia alashanica by the characters as follows:1) wings in both sexes deeply infuscate; each femur largely black on ventral side and largely pale brown on dorsal side; 2) the middle and lower parts of hind orbit without occipital carina; 3) the antennomere 3 clearly longer than the sum of antennomeres 4 and 5 together, and longer than the longest axis of eye as well; 4) the inner apical corner of valviceps aubquadrate. The new species differs from Cephalcia masuttii as follows:1) wings in both sexes deeply infuscate; 2) the mesoscutal lateral lobes and metascutellum in both sexes, male mesoscutellum, the ventral side of each femur and the abdominal tergites 1-6 in both sexes largely black; 3) the ventral 2/5 of paraantennal area naked and smooth; 4) antenna with about 26 antennomeres; 5) the valviceps without distinct anal corner. The K2P distance between the COⅠ of Cephalcia infumata and C. alashanica is 5.2%.

[Objective] In order to provide basis for improving drying rate,reducing energy consumption and the high value-added utilization of poplar lumber, the effects of pretreatment with superheated steam (SHS)on conventional drying rate, drying quality and drying time of poplar lumber (Populus tomentosa) were studied in this paper.[Method] The SHS pretreatment conditions were following:the temperature was 110, 120 and 125℃ respectively, and the duration was 5 h. The sample dimension was 900 mm×120 mm×50 mm(longitudinal×radial×tangential), and the initial moisture content(MC) was ranged between 100% and 150%. The effects of SHS pretreatment on the MC, stress, appearance quality and drying rate during the conventional drying of poplar lumber were analyzed. Furthermore,the drying quality of poplar lumbers with SHS pretreated and untreated was evaluated respectively according to the Chinese national standard.[Result] 1) The results of SHS pretreatment showed that the MC decline ratio was increased from 59.26% to 77.11% as the SHS pretreatment temperature increasing from 110℃ to 125℃, and MC of lumber was remarkably decreased and close to fiber saturation point (FSP) in a short time by SHS pretreatment. Residual stress in the SHS pretreated lumbers was ranged from 2.71% to 7.75%. Appearance quality index of the SHS pretreated specimens met the requirements of the 1^st drying grade. However, the collapse ratio of SHS pretreated lumbers was ranged from 25.00% to 36.96%. 2)Experimental result of conventional drying revealed that the average drying rate of lumber pretreated by SHS under the temperature of 110, 120 and 125℃ was increased by 7.97%, 16.52% and 78.42% in comparison with conventional drying index of the untreated lumbers. The drying quality index of drying uniformity among different boards and MC deviation in thickness met the requirements of the 1^st grade in accordance with national standard of lumber drying quality. However, the final MC met the 2^nd grade requirements. Additionally,residual drying stress generated in SHS pretreatment was released in the following conventional drying process, and met the 2^nd grade requirements. Appearance quality index of the SHS pretreated lumbers after conventional drying met the requirements of the 1^stdrying grade.The collapse occurred in SHS pretreatment was partly recovered during the following conventional drying process.Compared with SHS pretreated lumbers, collapse ratio of the conventional dried lumbers was decreased to 28.60%, 9.09% and 15.00%, respectively.3)Results of total drying time analysis showed that the total drying time of the lumbers pretreated by SHS under 110,120 and 125℃ was decreased by 24.96%, 44.22% and 67.24% as compared with the conventional dried lumbers.[Conclusion] The MC of poplar lumbers was decreased significantly by SHS pretreatment. The drying rate was improved, and the drying time was shortened in the following conventional drying process. In overall consideration of the drying quality and drying efficiency, the optimized SHS pretreatment temperature of 50 mm-thick poplar lumber is 120℃.

[Objective] The load-carrying capacity of light wood trusses made with domestic Larix kaempferi was investigated in this study, which provided a scientific basis for the development of light framing wood construction in China.[Method] Six parallel chord trusses were fabricated with Larix kaempferi and domestic truss plates in two types. The ultimate load, stress distribution and failure mode of light wood trusses were studied by static load test, then the results were compared with that of finite element model.[Result] The results indicated that the ultimate loads of P and L type light wood trusses were 22.45 kN and 22.94 kN, respectively, which were 2.27 and 2.32 times as large as the design load. The variation coefficients of P and L light wood trusses were 7.9% and 7.1%. The failure mode of P type light wood truss was brittle failure, and the failure mainly occurred at the trisection points of truss where concentrated load applied and two ends where the diagonal member connected with the top chord. Out plane deformation always observed in the L type light wood truss when the load reached about twice of the design load, and it reached its load-carrying capacity when the lateral deformation was large enough. Through the SAP 2000 finite element simulation, it could be found that the joint deflection was almost consistent with the experimental results. The maximum deflection was in the mid-span and decreased gradually to both ends. The maximum bending moment and the maximum axial force were obtained at the trisection points of the truss and the ends joints connected with diagonal member, which was coincided with the experimental results.[Conclusion] Both of the two kinds of light wood trusses possess good load-carrying capacity under design load, but they show a certain degree of dispersion due to the wood heterogeneity and the processing types. The bearing capacity of L type light wood truss is higher than that of P type light wood truss, but it is more prone to lateral deformation for the out of plane,which stiffness is small and need to be strengthened in application. The P type light wood truss is more stable to practical application. Moreover, the weakest point of the parallel chord light wood truss exists at the end joint and the joint where concentrated load applied, which is consistent with the test results. SAP 2000 can be used to predict the stress and deformation of light wood truss in practical application.

[Objective] 1) To explore the influence of die temperature on relaxation density, durability, and densification pressure of sawdust using the heating method. 2) To optimize the moisture content and heating temperature and find out proper process parameters for practical production.[Method] 1) Single factor design:the sawdust with the moisture content of 10%,12%, 14%, 16% and 18% was used as raw materials, the individual heating temperature of AC(ambient temperature), 50, 75, 100, 125, 150, 175, 200, 225 and 250℃ was applied, and pellets were produced by a self-developed single pellet extruder. The relaxation density, densification pressure and durability chart were drawn for further analysis. 2) The second regression general rotary combination design:the experiment was designed according to the result from single factor experiment. The charts of response surface of heating temperature and moisture content were drawn to analyze the interaction between relaxation density and densification pressure.[Result] 1) 10% moisture content:sawdust could be densified at the temperatures higher than 200℃, while the densification pressure was higher than 95.74 MPa;18% moisture content:the pellets were cracked, easily broken, and densification effect was bad. 2) When the heating temperature was controlled from 75℃ to 175℃, surface carbonization occurred and the higher the temperature was, the serious carbonization occurred on the surface. When the temperature reached 200℃ or higher, significantly decreased was found for the densification effect. 3) The densification pressure of pellets with different moisture contents generally decreased when the temperature increased from 75℃ to 225℃. 4) No significant difference was found among the durability of pellets with different moisture contents when the temperature was ranged between 75℃ and 200℃. When the temperature increased higher 200℃, the durability decreased sharply. 5) The results of ANOVA analysis showed that the model P of the relaxation density and the densification pressure were less than 0.001. The R² values were 0.93 and 0.99 respectively (both of them were more than 0.8), and the data of the equations were in accordance with the experimental result.[Conclusion] Heating method can effectively reduce the densification pressure, and thereby decrease the energy consumption in the densification process. 2) High-density pellets can be produced by sawdust with 14% moisture content using die heating method.3) When the relaxation density meets the requirement of medium density pellets standards (> 0.7 g·cm^-3) and the durability is above 90%, the densification parameters with minimum densification pressure are:heating temperature is 200℃, and moisture content is 12%.

Growth stress is generated in order to keep the trunk straight, or the branches back to the normal position of trees. Trees with this stress site is called reaction wood. In natural hardwood species, tension wood is formed usually when tree is tilt, or bending and partial crown. However, in the vertical trunks of plantation fast-growing species, there exists a lot of tension wood, but its structure and properties are different from normal wood which brings a series of problems in wood processing and utilization. The fibre cell wall structure of tension wood is very different from that of normal wood, especially in the inner surface of the fiber there is a cell wall layer with special morphology and chemical component, which is called gelatinous layer. This layer has many characteristics such as high content of cellulose, large crystallinity, low lignin content, small microfibril angle and abundant nanopores. Due to the occurrence of gelatinous layer is directly correlated with high tensile stress generation of tension wood, when this layers are concentrated, wood is prone to produce a series of problems such as twisting, cracking, sawing and pilling on the board surface during wood drying and processing, which seriously restricts the cultivation on high-quality plantation and the reasonable utilization of wood,resulting in a lot of economic losses. Therefore, to deeply understand the differences in tension wood and normal wood, especially the internal relations of special structure, chemical composition and biological function of gelatinous layer is the key to explore the high tensile stress generation mechanism, as well as the frontier intersection research in wood science, botany, tree physiology and materials science. This will reduce the loss caused by tension wood defects, improving the quality and utilization of wood. This paper reviews the research on the anatomical structure and structure characteristic of chemical component of gelatinous layer in tension wood, especially the research on the distribution of gelatinous fibers in tension wood, anatomical structure, pore structure and main chemical component of gelatinous layers were introduced in detail, in order to analyze the structure and characteristics of gelatinous layer during tension wood generation, as well as to provide the basis data for the mechanism of high tensile stress generation. According to the common characteristics of plantation in China such as high proportion of tension wood and uneven wood quality, the main scientific problem need to be solved in the current academia and industry is to understand the amount and ratio of species which are easy to form tension wood, the ratio of tension wood with gelatinous fibers and the mechanism of tension wood generation. At the same time, the further research can focus on the regulating mechanism of tension wood formation and development, the dynamic change of the structure and properties in gelatinous layer, the multiscale structure characterization of gelatinous layer and the study of tension wood with gelatinous layer absent. Finally, it will provide a theoretical basis for high efficient and high value utilization of the plantation forest resources in China.

[Objective] Fine root decomposition law, element release rule and corresponding influencing factors were analyzed towards Caragana intermedia and Caragana korshinskii plantations in Qinghai alpine sandy land in 1990, which contributed to the evaluation of long-term adaptability of these two Caragana plantations in Gonghe Basin, and further provided theoretical basis on long-term research of Alpine sandy soil's carbon and nutrient cycle.[Method] The buried bag method was adopted in May 2015, and comparison was done on mass loss rate and element (C, N, P, K) release rate between the two Caragana species with fine roots of different diameters (1-2, 0.5-1,and 0-0.5 mm) during 489 days' decomposition process. The correlation between initial concentrations and mass loss rates was studied, and dynamic characteristics of fine root decomposition was analyzed. In addition, fine root decomposition coefficient and the time required for 50% and 95% decomposition were determined by nonlinear exponential regression.[Results] Mass residual rate was 53.28%-66.34% after 120 days' rapid decomposition process, followed by a slow decomposition phase (120-360 d) and slowly speeding period (360-489 d). Fine root mass of the two Caragana species experienced a remarkable drop after 489 days' decomposition, and mass residual rate achieved 39.94%-58.20%. Tree species, fine root diameter class and decomposition time had significant effect on fine root mass loss rate, respectively. Time for 95% decomposition was 17.18,14.96,and 12.57 a for Caragana intermedia with fine root diameter of 0-0.5, 0.5-1, and 1-2 mm, respectively, while 27.35, 26.41, and 14.77 a for Caragana korshinskii. Chemical elements release rate of C was 56.34%-79.70% and 44.37%-87.39% for Caragana intermedia and Caragana korshinskii, respectively, while the value of N achieved 62.73%-3.43% and 54.41%-8.63% after 489 days' decomposition. Pairwise interaction of tree species, fine root diameter class and decomposition time had non significant effect on element release rate.[Conclusion] In this study, fine root decomposition rate and cumulative element release rate of Caragana intermedia was larger than that of Caragana korshinskii. Fine root of Caragana intermedia, especially those with Ø1-2 m, released chemical elements (C, N, P, K) faster, which contributed to circulation of soil organic carbon and nutrients, and further benefited soil amelioration in alpine sandy area. Therefore, Caragana intermedia should be selected as typical tree species for wind break, sand fixation and soil reclamation.

Aluminum toxicity is a primary limiting factor for plants grown in acidic soils. Some ectomycorrhizal (ECM) fungi may improve the tolerance of their host plants against Al toxicity mainly by enlarging the uptake scope of nutrients, enhancing the availability of mineral nutrients, and/or inhibiting Al uptake by the host. Although these benefits have been partly illustrated in some ECM fungus species in vitro or in hydroponic or sand culture experiments, most focused on rhizoshere and fewer studies have examined the roles in field, and the transportation of nutrients and Al in plants still remained unclear.[Objective] In order to learn about the Al-tolerance of ectomycorrhizal seedlings, to select excellent ones, and to explore the nutritional mechanism,[Method] three isolates of Laccaria bicolor, namely Lb S238 A, Lb S238N and Lb 270, respectively, were used to inoculate Pinus massoniana seedlings to evaluate the growth, uptake and distribution of nutrients and Al in plants under Al-exposure. The seedlings were pre-planted for 4 weeks in native acid yellow soil from a masson pine stand, and then irrigated weekly with Hoagland nutrient solution containing 0.0 or 1.0 mmol·L^-1 Al³⁺ supplied with Al₂(SO₄)₃·18H₂O at pH 3.8 for 12 weeks.[Result] Exposure to Al stimulated the growth and uptake of P, Ca, Mg, and Al of seedlings inoculated with Lb S238A,whereas inhibited the growth of seedlings inoculated with Lb S238N or Lb 270, and inhibited uptake of Ca and Mg of Lb 270 seedlings. However, inoculation with any of the three isolates improved the growth and uptake of P, Ca, and Mg, but reduced or maintained Al uptake of seedlings under Al-exposure, with Lb S238A the best, compared to nonmycorrhizal (Non-ECM) seedlings. Inoculation with Lb S238A increased the seedling's growth by 69.9%, P uptake by 68.9%, Ca uptake by 69.7%, and Mg uptake by 81.5% under Al-exposure. Meanwhile, the improvement on growth from inoculation with any of the three isolates mainly exhibited on stem and on needles, with higher increment on stem than on needles. Inoculation with Lb S238A or Lb S238N decreased Al concentrations in each part of the seedlings, and Lb 270 decreased that in roots and in stem, with higher decrement in stem than in roots and in needles; Lb S238A or Lb 270 decreased Ca concentration apparently in stem and in roots, respectively, but Lb S238N increased that in needles. Inoculation with any of the three isolates decreased P concentration in roots but increased that in needles, and reduced distributions of P, Ca, and Al in roots but promoted those in needles.[Conclusion] Inoculation with any of the three isolates of L. bicolor improved the Al-tolerance of masson pine seedlings through the following ways:1) enhancing the uptake of P, Ca, and Mg; 2) reducing the distribution of P and Ca in roots and proceeding them upward to the stem and needles; 3) inhibiting or maintaining Al uptake and diluting Al concentration to a non-toxic value in seedlings. Among the tested three isolates, Lb S238A should be the best for masson pine seedlings to plant in acidic and allitic soils, and Lb S238N or Lb 270 should be suitable in acidic soils containing less aluminum. It needs to explore the role of ECM fungus on mechanism about transporting of nutrients and Al in ECM seedlings exposed to Al in the further study.

[Objective] In this study,Photosynthesis and chlorophyll fluorescence characteristics of seedling and sapling leaves of Taxus cuspidata were studied to explore the reasons for the photoinhibion of seedlings after removal of shading, which provide would theoretic basis for the development of Taxus cuspidata cultivation in Northeast China.[Method] Seedlings and saplings of Taxus cuspidata grown under shade condition (approximately 40% of the natural light intensity) were taken as the materials. They were moved to full sunlight for 28 days before the experiment was carried out. Then differences of pigment, photosynthesis and chlorophyll fluorescence characteristics of seedling leaves and sapling leaves were measured.[Result] The result showed that there was no significant difference between seedling leaves and sapling leaves in chlorophlly content. Sapling leaves had a higher content of cartotenoid and a lower value of Chl/Cars significantly. The maximum photosynthetic rate of seedling leaves was only 70% of that of sapling leaves after 28-day full sunlight. Seedling leaves had a lower light compensation point and light saturation point, but apparent quantum yield of photosynthesis (AQY) was higher. In this case, more excessive energy was produced in seedling leaves under full sunlight condition. Meanwhile, compared within sapling leaves, carboxylation efficiency (CE), regeneration rate of RuBP and A_max in seedling leaves were lower as well. Theses results indicated that the activity of Rubisco enzyme and the assimilation ability of CO₂ in seedling leaves were relatively lower. Seedling leaves and sapling leaves of T.cuspidata showed different photosynthetic responses to high light intensity in a short period. The sapling leaves reached the maximum photosynthetic rate in about 25 min under high light, while seedling leaves reached the maximum photosynthetic rate in about 50 min. From low light to high light, actual photochemical efficiency (Φ_PSⅡ) and non-photochemical quenching (NPQ) of sapling leaves reached their maximum values in a shorter time as compared with those of seedling leaves. In addition, the Φ_PSⅡ of seedling leaves reduced with the increase of PFD, while that of sapling leaves decreased slightly. Moreover, NPQ of sapling leaves reached a relatively higher level with the increase of PFD, while seedling leaves attained their maximum value with a low light intensity.[Conclusion] A lower photosynthetic rate of the seedlings resulted in relatively excessive light energy,which made seedling leaves susceptible to photoinhibition after changing to full sun light.

[Objective] Protapanteles lamborni is a dominant larval parasitoid of Crypsiptya coclesalis. Understanding of biological habits of P. lamborni would provide the fundamental information for biological control of C. coclesalis.[Method] In this paper, the field investigation and laboratory tests were used to study the parasitic characteristics of P. lamborni.[Result] Result showed that adults of P. lamborni mainly emerged between 8:00 and 10:00 am, so that they could copulate and lay eggs on the same day. The adult could perform both amphigony and arrhenotoky. In the range of 16℃ to 32℃, the adult development period at 16℃ lasted maximally for 6.65±0.24 days, however it could be 13.35±0.37 days if 10% honey solution was added as supplementary nutrition.[Conclusion] P. lamborni had an increasing parasitic rate with generations of the host of C.codesalis, and it mainly parasitized the third or fourth instar larvae of C. codesalis. Within a certain range of temperature, the developmental duration of P. lamborni decreased with the increase in temperature, but the adults could extend their longevity significantly if being supplied with 10% honey solution as supplementary nutrition.