[Objective] To explore the best tending measure,the thinning intensity experiment was carried out in the secondary forest of the mixed coniferous and broad-leaved forest to analyze the effect of different thinning intensities on stand growth and species diversity,and to provide a guidance for rational management of forestation activities in the region.[Method] Four permanent plots with a size of 1 hm² were established for thinning experiment in the secondary forest of the mixed coniferous and broad-leaved forest in Jiaohe Forestry Experimental Bureau of Jilin Province in July 2011.The thinning intensities were set by basal area,which were 0%(control,CK),17.24%(light thinning,LT),34.74%(medium thinning,MT),and 51.87%(heavy thinning,HT).Five sample plots (20 m×20 m) were selected from each standard plot to determine the actual thinning intensity.2 and 4 years after thinning,the DBH,tree height,basal area,stock volume,species diversity and community similarity were measured and analyzed,and the impacts of thinning intensity were studied.[Result] 4 years after thinning,the average DBH increment of the stands increased compared with the control.There was no significant difference between other treatments and the CK (P>0.05),except for the significant increase of LT treatment (P<0.05).The average tree height and growth rate of the stand were lower than that of the CK,but there was no significant difference among the treatments (P>0.05).The total basal area and stock volume of the stand were lower than those of the CK,showing that they decreased with the increase of thinning intensity.However,LT and MT treatments increased the increments of individual basal area and stock volume,and HT treatment was reversed,there were no significant difference among treatments (P>0.05).2 and 4 years after thinning,the shrub layer,the herb layer and the overall abundance increased significantly,but the HT treatment reduced the abundance of the tree layer.Compared with 2 years after thinning,the herb layer was reduced 4 years after thinning.Thinning did not change the species richness,diversity and evenness of the tree layer,but significantly increased the Shannon-wiener index and the Simpson index of shrub layer and herb layer.The MT treatment had the most obvious effect on the increase of species abundance,richness and diversity.The community similarity index was higher among treatments,all the similarities were at moderate or high level.[Conclusion] Thinning had a certain promoting effect on the growth of DBH in short-term,but it has not promoted the growth of stand height.Although thinning has not promoted the increase of total basal area and stock volume of stand,a rational thinning intensity could significantly increase the individual increment of basal area and volume,and promote the species diversity of shrub layer and herb layer.Considering the growth of forest and maintaining species diversity,the most suitable thinning intensity of near-maturing mixed coniferous and broad-leaved forests in Northeast China was 34.74% in this study.

[Objective] Urban green belt is one of the most important ecological infrastructure.In this paper,using the concept of urban forest,RS and GIS technologies,we took the second green belt in Beijing as an example and explored the temporal and spatial dynamics with the urban tree canopy (UTC) from 2002 to 2013,in order to evaluate achievements of the ecological construction,and to reveal the process of landscape pattern changes,trend and driving forces,and to provide experiences for deepened ecological construction and maintenance of ecological infrastructure in the region.[Method] Based on 2002 aerial photo and 2013 Worldview2 images with a resolution of 0.5 meter,the urban tree canopy (UTC) of 2002 and 2013 within the second green belt were interpreted by using the eCognition 9.0 software as the platform of object-oriented interpreting technology.The landscape pattern index,which include the patch number,mean patch size (MPS),Mean patch fractal dimension (MPFD),mean shape index (MSI),mean patch edge (MPE),Shannon diversity index (SDI) and Shannon evenness index (SEI),were employed.In the analysis of changing reasons,the related statistical data were used in indentifying driving forces.[Result] The UTC area within the second green belt increased from 28 839.84 hm² in 2002 to 63 709.95 hm² in 2013,and UTC rate increased by 21.4%.The UTC patch number were decreased from 343 605 to 189 168 over this 11 years,and the impervious ground surface and grassland increased by only 8.89% and 8.89% respectively.The landscape matrix was constituted by agriculture land and impervious ground surface in 2002,but in 2013 which were transformed into the UTC and impervious ground surface.The values of landscape pattern index,such as MPFD,MSI,SDI,and SEI,showed a downward trend.This indicated that the extents of naturalization of the landscapes were gradually increased in the study area.The most stable patch type was the impervious ground surface and UTC,of which the unchanged area ratios were 64.59% and 60.34% respectively,and more than 95% of the bare land patches type was changed.From the view of changes on patch classes,both the number and area were decreased in small patch,medium patch,large patch and extra large patch.Only the huge patches were increased in the patch number and patch area.All these changes were driven by several factors including the implementation of the second green belt plan from 2003 to 2010,overall urban planning (2004-2020),river course treatment and ecological construction of Yongding and Wenyu rivers,development of new rural areas,and the urban forestation project entitled "One Million Mu Plain Afforestation Project".[Conclusion] It can be seen from the landscape changes of 11 years that the construction effect of the second green belt is very significant.Compared with the initial stage of construction,the UTC and impervious ground surface are the two fastest growing LUCC types,in which the increasing ratio of UTC is faster than that of impervious surface.From the perspective of the landscape pattern,the degree of artificial influence on patches in the whole study area is slowing down,and the degree of naturalization of landscape patches is increasing.All of these changes show that the UTC has rapid expansion in the area,and its potential role in urban biodiversity conservation is becoming more and more important.

[Objective] In this study,the dry-wet seasonal variation characteristics of sap flow of the two afforestation poplar species in semi-arid Lhasa river valley,and the environmental impact factors were investigated in order to provide a theoretical base for species selection for vegetation reconstruction in the river valley.[Method] The Granier's thermal dissipation probe was employed to continuously measure the stem sap flow of Populus beijingensis and Populus szechuanica during the wet and dry seasons.At the same time,environmental factors,such as solar radiation (Q),air temperature (T_a),soil water content (SWC),and vapor pressure deficit (VPD),were recorded.[Results]The main meteorological factors in the Lhasa river valley were quite different in wet and dry seasons.The Q,T_a,SWC,and VPD values during the wet season were higher than that in the dry season,and the average of them in the dry season wrer around 60% of those in wet season.In both seasons,the sap flow velocity in P.beijingensis was lower than that in P.szechuanica.The sap flux density of P.beijingensis was 71% and 58% lower than those of P.szechuanica during the dry and wet seasons,respectively.During the dry season,the sap flux density of two poplars declined by 65% and 76% compared with that in wet season.The main environmental factors of Q and VPD had less influence on the stem sap flow of P.beijingensisthan on that of P.szechuanica.[Conclusion] In the Lhasa river valley area between dry and rainy season,the sap flux density of two poplar species all had obvious circadian rhythm.However,there were significant differences in peak value,daily average value,start-up time and the impact environmental factors between the two species,especially in the dry season.P.szechuanica,as native tree species,showed a stronger adaptability.

[Objective] Ca²⁺-dependent-deoxyribonuclease (CDD) can degrade ssDNA and dsDNA,however it is unclear that the function in response to drought and severe salt stresses.In this study,the role of CDD in growth and development of poplar trees (Populus alba×P.glandulosa ‘84K’) and the possible molecular mechanism in response to drought and salt stresses were analyzed,in order to provide a foundation for the elucidation of the regulatory role of CDD in stress tolerance of poplars.[Method] PtoCDD overexpressed and PagCDD knockout poplar lines (cuttings from tissue-cultured plants) were treated in drought and severe salt stresses and the phenotypes were accessed,including growth and adventitious rooting (AR).The anatomy of stem sections of transgenic lines and control plants (84K) were performed and the layers of xylem cells were compared.The expression of PIP in CDD transgenic poplar lines in response to drought and salt stresses were also analyzed by qRT-PCR.[Result] There were no significant differences between the transgenic poplar lines and the non-transgenic 84K in normal condition,while CDD knockout plants and CDD overexpressed plants respectively exhibited significantly higher and shorter than the control plants under the drought and salt stresses.This analysis indicated that CDD overexpression enhanced the sensitivity of poplars to the stresses.The anatomy analysis revealed that the layers of xylem cells were in the sequence of CDD overexpression lines > control 84K > CDD knockout lines from thick to thin in normal condition,while CDD knockout lines > control 84K > CDD overexpression lines under the stresses.The anatomy analysis demonstrated that the involvement of CDD in xylem differentiation was significantly affected by the stresses.In addition,the number of ARs exhibited CDD knockout lines > control 84K > CDD overexpression lines in the sequence from high to low,thus the CDD expression level could alter the number of ARs thus change the sensitivity of poplars in response to the stresses.qRT-PCR analysis showed that the expression of certain PIPs involved in responding to the the stresses were up-regulated in overexpression lines.This study demonstrated that CDD could induce the expression of certain PIP members to alter water usage.[Conclusion] Overexpression and knockout CDD could alter the expression of PIP,water usage,and the number of AR,of transgenic poplars,leading to the change in growth and development and the display of different sensitivity under the drought and salt stresses.Therefore,CDD is involved in the process of responding to the drought and salt stresses in poplars.

[Objective] Betula halophila was recorded as an endangered species in the list of plant species with extremely small populations (PSESPs).In this study,we used high-throughput sequencing technology to sequence its chloroplast (cp) genome to understand the structure of B.halophila cp genome as well as the potential simple sequence repeats (SSRs) markers.We also compared the cp genome of B.halophila with those of the phylogenetically related species to understand the hotspot region in Betulaceae.[Method] Total genomic DNA was extracted from fresh leaf samples using the Plant Genomic DNA Kit (Tiangen Biotech).The HiSeq Xten platform was used for library construction and sequencing.MITObim v1.8 and NOVOplasty were used to assemble trimmed reads with the cp genome of B.nana as the reference.[Result] Totally,30 000 000 reads were obtained after trimming.The B.halophila cp genome (Accession Number MG674393 in NCBI) was a typical circular double-stranded DNA molecule with 160 648 bp in length,and its quadripartite structure was similar to most angiosperms,which comprised of LSC region (89 553 bp,GC content 33.7%),SSC regions (18 159 bp,GC content 29.7%) and IRs regions (IRa and IRb,26 689 bp each,GC content 42.5%).Four unique rRNAs,31 tRNAs,and 79 protein-coding genes were annotated.We further detected 91 SSRs,of which 33 SSRs were composed of A or T,and 56,13,and 22 SSRs were at the LSC,SSC and IRs,respectively.The sliding window analysis showed three highly variable regions (hotspots) under a criterion of nucleotide variability >0.2:ndhC-trnV,petA-psbJ,and rpl22-rps19.All of these hotspots locate at the LSC region.In contrast,the SSC and IRs regions are relatively conservative.In addition,four genes of ycf1,rpoC1,rpl2,and ndhA were signaled with positive selection.Phylogenomic reconstruction with 13 dicotyledonous plants revealed that nine of the 11 nodes had 100% supports for grouping in both MP and NJ trees.The phylogenomic analysis indicated that B.halophila was close to B.nana and sister with Ostrya rehderiana.[Conclusion] Via the high-throughput sequencing and the bioinformatic analyses of the cp genome of B.halophila,we found the similar organization,gene contents and SSRs distribution with B.nana cp genomes.Three identified highly variable regions in LSC are applicable for DNA barcodes for species identification,plant breeding,and phylogenetic inference.Four positively selected genes deserve further investigation.It provides important genetic information for the future protection of B.halophila.

[Objective] GA2-oxidase (GA2ox) is a key enzyme which plays a negative role in regulating the gibberellins.GA2ox could convert bioactive gibberellins to inactive gibberellins during gibberellin biosynthesis.Accordingly,it has a certain inhibitory effect on plant growth.This experiment was aimed at cloning and verifying function of GA2ox encoding gene (JrGA2ox) in walnut (Juglans regia).It helps to further explore the role of JrGA2ox gene in the process of plant growth and development,especially in regulating the plant height.This further assists in discovering and utilizing more high-qualified genes in walnut and cultivating more improved walnut varieties.[Method] The full length of JrGA2ox gene was cloned and verified based on PCR technique.Furthermore,the 35S::JrGA2ox::GFP overexpression vector with a strong promoter was constructed by In-Fusion cloning technology.The JrGA2ox homologous amino acid sequences were obtained by the online tool of BLAST,and their comparative analysis and phylogenetic tree analysis were carried out.Thereafter subcellular localization assay was carried out to reveal where it worked.The overexpressed vector was transformed into walnut somatic embryos using the Agrobacterium-mediated method and the positive transformation plants of JrGA2ox overexpression types were obtained.Furthermore,the biological properties of JrGA2ox gene were further analyzed.[Result] The 1 056 bp open reading frame (ORF) of JrGA2ox was gained by cloning method,encoding 351 amino acids and its molecular weight was 39.25 kDa.Blast analysis showed that JrGA2ox had a common structural feature of GA2-oxidase family which was a conserved protein domain named 20G-FeⅡ-Oxy.It indicated that JrGA2ox belongs to GA2-oxidase gene family.The results of phylogenetic tree analysis showed that JrGA2ox and Populous tomentosa GA2ox were clustered into the same branch.And the protein encoded by JrGA2ox gene had a high homology with those proteins of woody plants,Morus notabilis GA2ox1,Pyrus communis GA2ox,Prunus persica GA2ox1,and Malus domestica GA2ox1.The analysis of subcellular localization assay in epidermal cells of tobacco (Nicotiana benthamiana)-leaves showed that JrGA2ox was mainly localized in the nucleus and plasma membrane.The results of GFP fluorescence detection and PCR inspection in the transformed somatic embryos showed that 35S::JrGA2ox::GFP had been transformed into walnut somatic embryos successfully.Comparing with the regenerated wild type walnut plants,there was a significant difference in plant height.The average height of the transformed plants was 1/2 of that of the control and it was negatively correlated with the expression of JrGA2ox gene.[Conclusion] The results indicated that JrGA2ox was located in the nucleus and plasma membrane.In addition,JrGA2ox gene regulated the height of walnut plants negatively.When the relative expression level raised in the transgenic walnut plants with 35S::JrGA2ox::GFP,these plants showed obvious dwarfing characteristics.This study provides a technical basis for further analysis of the functions of JrGA2ox gene in growth and development and for the breeding of dwarf walnut varieties.

[Objective] In this paper,we explored the possibility of defining relationships between remote sensing features that come from GF-2 and species diversity indices for subtropical forest in Gutian Mountain of Zhejiang Province,China.[Method] We extracted the reflectance values,spectral indices,texture from GF-2 data.Random forest models were used to select variables and estimate species diversity indices.We compared the texture values that come from different window size to find the best window size for species diversity estimation.[Result] Based on the random forest (RF),recursive feature elimination (RFE) was used to find small subsets of features with high discrimination levels on data sets,which provide good performance for species diversity modeling.For the multispectral (MSS) data,the best window size is 3×3,and for the panchromatic (Pan) data,the best window size is 7×7.Both texture features and spectral indices were selected for species diversity modeling and the Carotenoid reflectance index provided the best performance.The determinate coefficient and RMSE for three species diversity are 0.47 and 0.300(Shannon-Wiener diversity index),0.53 and 0.042(Simpson diversity index),0.61 and 0.051(Pielou evenness index),respectively.[Conclusion] The result demonstrated that the GF-2 data can be used to model tree species diversity effectively.Predictive map derived from the presented method ology can help evaluate spatial aspects and monitor tree species diversity of the studied forest and facilitate the evaluation of forest management and conservation strategies.

[Objective] Climate change has increased the need of information on amount of forest biomass.The purpose of this study is to develop compatible individual tree biomass and volume equations,providing a quantitative basis on accurate estimation of forest biomass.[Method] Based on the mensuration data of above-and belowground biomass from 301 and 104 destructive sample trees of Masson pine (Pinus massoniana) in southern China,respectively,one-and two-variable systems,which combined aboveground biomass and stem volume equations with belowground biomass equation,and ensured them compatible with biomass conversion factor and root-to-shoot ratio equations,were developed using dummy variable modeling approach and error-in-variable simultaneous equations approach,and effects of region and origin on estimation of biomass and volume were analyzed.[Result] The coefficients of determination (R²) of one-and two-variable compatible individual tree biomass and volume equations for Masson pine developed in this study were more than 0.92,whereas the mean prediction errors (MPEs) of above-and belowground biomass equations were less than 4% and 8%,respectively.For estimation of aboveground biomass and stem volume of Masson pine,two-variable equations were significantly better than one-variable equations,for the F-statistics between one-and two-variable aboveground biomass and stem volume equations were greatly larger than the critical F value.But for estimation of belowground biomass,one-variable were even better than two-variable ones.Effects of region and origin on estimation of both one-and two-variable aboveground biomass equations were not significant,indicating that aboveground biomass equations of Masson pine were generalized on national level.Furthermore,the general allometric biomass model M=0.3ρD^7/3presented by Zeng et al.(2012) was proved to be applicable in practice.For estimation of belowground biomass of Masson pine,models in different regions were significantly different.For trees with the same diameter,estimate of belowground biomass in the region of modeling population 1(south-eastern part of Yangtze River basin) was larger than that in the region of modeling population 2(central-western part of Yangtze River basin).For estimation of stem volume of Masson pine,two-variable model was not affected by region and origin,whereas one-variable model was affected by origin.For trees with the same diameter,estimate of stem volume in a planted stand was larger than that in a natural stand.[Conclusion] Integrating dummy variable into error-in-variable simultaneous equations is a practical approach,which not only can ensure the compatibility among several target variables,but also can develop simultaneously a system even though numbers of above-and belowground biomass observations are very different.The biomass equations,volume equations,and compatible biomass conversion factor equations and root-to-shoot ratio equations developed for Masson pine in this study meet the need of precision requirements to relevant regulation,and can be used in application.

[Objective] The effects of different segmentation scales and characteristics of objects on object-oriented forest gap based on aerial orthophoto were studied,and the suitability of forest gap classification based on aerial orthophoto was also evaluated in this research.[Method] In this study,based on true color aerial orthophoto data and object-oriented classification method,northeastern typical natural secondary forest-Mao'ershan Experimental Forest Farm Donglin industry zone was selected as the study area for classification of forest gap.In the process of object-oriented classification,for three components of aerial orthophoto (Blue,Green,Red),10 scales (10-100,step size 10) was divided to carry out segmentation,and topological combination accuracy (R_A(or) and R_A(os)) and position accuracy (D_sr) were used to evaluate the classification results.For each segmentation result of different scales,spectral features and combination features of spectrum and texture derived from aerial orthophoto were used,and support vector machine (SVM) with linear kernel classifier of object-oriented was used to classify the study area into forest gap,non-forest gap and canopy,totally 20 classification result were obtained.Later the accuracy of each classification result was evaluated by the 4 different evaluation indexes,namely producer accuracy calculated by Confusion matrix,user accuracy,classification accuracy and Kappa coefficient.[Result] Characteristics of objects (size and shape) were affected by scale parameter.Objects in small area were created by small scale segmentation,and objects in big area were created on large scale segmentation,however,segmentation of large scale could not efficiently distinguish obvious forest gaps from canopies,it indicates an obvious insufficient segmentation phenomenon.The topological combination accuracy (R_A(or) and R_A(os)) and position accuracy (D_sr) illustrated that the result of segmentation objects on 20 scale (R_A(or) and R_A(os) were higher and close,D_sr was lower) was most similar to the reference objects comparing to the result on other segmentation scales.The segmentation schemes of spectral features and combination features of spectrum and texture showed a similar variable trend:classification accuracies were lower on small scales,and then increased with scale increasing,after reached the maximum on a certain scale,they decreased to stable state.The classification accuracy using combination features of spectrum and texture was lower than that using spectral features only,especially on small scales.On the segmentation scale of 20,the overall classification accuracy using combination features of spectrum and texture was 19% lower than that using only spectral features,and accordingly 30% lower on the segmentation scale of 30.The optimal scale parameter of segmentation based on aerial orthophoto was 20.[Conclusion] The highest recognition accuracy was just 74%(Kappa=0.61) when using aerial orthophoto to recognize forest gaps,the producer and user accuracy of forest gap were all above 60%,and which of non-forest gap were around 90%.The classification accuracy based on aerial orthophoto would continually decrease when adding texture features.

[Objective] In order to improve the monitoring efficiency and precisely calculate forest carbon sequestration in afforestation projects in Guangdong Province,this study selected major broad-leaved tree species in Guangdong,such as Cinnamomum camphora,Schima superba and Liquidambar formosana,and established aboveground biomass models with age and diameter as independent variables.[Method] All 270 sample trees with 90 sample trees for each tree species were obtained according to 10 diameter classes during the process of modeling,using destructive experiments and stem analysis method to obtain tree biomass and age data.Using the dummy variable method to distinguish the different origins (natural forests and plantations),single tree biomass models with the diameter of breast height (DBH) and age were established for the three species.Also the aboveground biomass components (stem wood and bark,branches,foliage) were established for natural forests and plantations based on dummy variable method.The additivity or compatibility of the components of the aboveground parts was solved by the nonlinear simultaneous equation systems.[Result] The determination coefficients R_adj² of the three above-ground biomass models of the three tree species are between 0.89 and 0.94.It is feasible to use biomass model (1) with DBH and age to estimate tree above-ground biomass.Model (1) has good estimation result and is easy to use.After adding the dummy variable,the three above-ground biomass models R_adj² of the three tree species all reached 0.90 or more.Model (4) can further improve biomass estimate accuracy and refine the model application conditions;for the B-D-T based compatible biomass model system (7) there are good performances in 3 tree species.R_adj² of stem biomass model is between 0.90 and 0.95,R_adj² of bark biomass model is between 0.84 and 0.94,and R_adj² of branch biomass model is between 0.73 and 0.91.The R_adj² of the leaf biomass model is between 0.63 and 0.75,and a compatible B-D-T biomass model system (8) with dummy variables is constructed.The stem biomass equation R_adj² is between 0.88 and 0.97,and the bark biomass equation R_adj² is between 0.82 and 0.93,the branch biomass equation R_adj² is between 0.84 and 0.90,and the leaf biomass equation R_adj² is between 0.62 and 0.69.The result further indicate that the biomass model with DBH and age is more effective than the DBH and tree height biomass models.[Conclusion] This study established the aboveground biomass model with diameter and age for three major native broad-leaved tree species in Guangdong Province.The biomass compatibility model of each component in the aboveground biomass part was established by simultaneous equations.The single tree aboveground biomass model with the DBH and age model (1) have higher fitting accuracy than the commonly used two DBH and height model (2) and (3) and the model (4) with dummy variable also have higher fitting accuracy than model (5) and (6).The precision of nonlinear simultaneous equations (8) with dummy variables is higher than that of model system (7) with B-D-T.Meanwhile,the precision index of the dummy variable simultaneous equations (8) with the DBH and age variable is also better than that of the dummy variables simultaneous equations (9) and (10) with the DBH high variable.The simultaneous equations (8) not only ensure the compatibility between the aboveground biomass of each component,but also obtain more optimal parameter estimates from different origins.The single-wood biomass model with DBH and age (1) and the aboveground biomass model considering the origin (4),the model system (7),the biomass compatibility equations for the above-ground components with the DBH and age,and considerations the above-ground biomass compatibility equations (8) have higher fitting precision than the commonly used above-ground biomass models of DBH and tree height,and are more suitable for artificial broad-leaved forest and carbon sink afforestation projects (arbon sink measurement,monitoring and evaluation) in practice.

[Objective] This study aimed to investigate the relationships between soil mineral element contents and fruit shrinking disease (FSD) in Chinese jujube (Ziziphus jujuba) and explore effective control methods of FSD,in order to provide theoretical and technological support for the prevention of the serious jujube fruit disease.[Method] This study systematically compared the dynamic changes of nine main mineral elements in leaves and fruits of jujube in the course of occurrence of jujube fruit shrinkage disease in severe and light FSD area as well as targeted fertilization areas.[Result] The contents of potassium,manganese,copper and boron in leaves in light disease area were significantly higher than those in severe disease area,while the calcium content in leaves in light disease area was significantly lower than that in severe disease area.The potassium and manganese contents in fruits in light disease area were significantly higher than those in severe disease area,and the calcium content in fruits in light disease area is significantly lower than that in severe disease area.After targeted fertilization of potassium and manganese,FSD incidence was significantly reduced from 57% to 15%,meanwhile potassium and manganese contents in leaves and fruits significantly increased but calcium contents significantly reduced.Spraying fungicides and growth regulators on the basis of supplementing K and Mn is more effective in controlling fruit shrinkage.The optimal nutritional index in leaves for controlling FSD in Taihang Mountains jujube growing regions was preliminarily determined by using the principal component analysis,i.e.,potassium content in leaves was higher than 2.06±0.23 mg·g^-1,manganese content was higher than 261.83±21.54 mg·kg^-1,and calcium content was lower than 1.07±0.11 mg·g^-1.[Conclusion] The occurrence of FSD is closely related to lower contents of potassium and manganese and higher content of calcium.This study provides a new effective way to prevent and cure fruit shrinking disease via soil potassium and manganese application in Chinese jujube.

[Objective] Based on the national investigation of Obolodiplosis robiniae,the current and future (2050) sustainable habitats of O.robiniae in China were predicted by using the complementary log-log (Cloglog) of maximum entropy model.This study would provide an important reference for forestry and quarantine authorities to control and quarantine of O.robiniae at present and in the future.[Method] MaxEnt,ArcGIS,and R software were used to scientifically optimize the three aspects of the O.robiniae distribution points,bio-climatic variables and model parameter setting,to ensure the scientificity and validity of the model.The current bio-climatic variables for the suitable area were predicted by using WorldClim Website Global Weather Database Version 1.4,with5 min of spatial resolution.The future data were derived from three representative concentration pathways RCP26,RCP45 and RCP85 under CCSM4.[Result] A total of 52 distribution points and 7 bio-climatic variables were finally determined.The complementary log-log output format was used to predict the potential geographical distribution.The test omission rate of simulation results is basically consistent with the theoretical omission rate.The ROC (receiver operating characteristic curve),which has an AUC (area under the ROC curve) of 0.919 and a standard deviation of 0.023,indicating that the test and training data have no spatial autocorrelation and the constructed model meets the"excellent"standard.Through Jackknife test analysis,the three bio-climatic variables that have the greatest influence on O.robiniae distribution are Bio1(Annual mean temperature),Bio12(Annual precipitation) and Bio5(Max temperature of warmest month).For the current classification of the potential geographical distribution for O.robiniae,the suitable range is in the range of 22.08°-48.42°N,39.39°-135.06°E,accounting for 31.90% of the national area.With the exception of Tibet,Qinghai,Hainan,and Taiwan province,the other provinces have their own potential geographical distribution,and the highly potential geographical distribution regions are mainly in the southwest (Sichuan,Chongqing) and Northern China (Beijing,Tianjin,Hebei,Shandong,and Shaanxi).For the prediction of the future (2050),the total susceptibility zones of the three representative concentration pathways RCP26,RCP45,and RCP85 are larger than the total habitats in the current climate,especially for high and moderate suitable habitats.The areas in Xinjiang and northern China will expand significantly.The risk area under the RCP85 scenario is the largest,reaching to 39.71% of the national area,750 000 km² more than the current prediction.[Conclusion] Combined with the actual investigation,the novel MaxEnt model has high reliability to clarify the dominant climatic factors affecting the distribution of O.robiniae,and predict the distribution and fitness of O.robiniae current and future (2050),which is of important value for the prevention and control of O.robiniae.

[Objective] This study aimed to study the role of small heat shock protein (sHSP) in parasitoids and explore the resistance of the heat shock proteins from parasitic natural enemies to pesticides and ultraviolet stress.[Method] The small heat shock protein gene of Chouioia cunea(Ccshsp12.2) was cloned and was used for constructing a phylogenetic tree,calculating amino acid substitution rate and codon usage bias.The RT-qPCR technique was used to quantify the relative expression of Ccshsp12.2 under ultraviolet and treatments with four kinds of pesticides (Abamectin,Bacillus thuringiensis,chlorbenzuron and Beta-cypermethrin).[Result] The Ccshsp12.2 gene with complete ORF was obtained,encoding 206 amino acid with a molecular weight of 23.1 kDa.The phylogenetic trees showed two lineages,Ccshsp12.2 was clustered with other parasitoids in to one group,while Cephus cinctus was clustered with other independent Hymenoptera insects into the other.The average value of Ka/Ks (dN/dS) in 9 selected mRNA sequences is 0.674 067,which means that those genes appear to be primarily negatively selected.In addition,the average codon usage bias of parasite insect is 0.344,while it is 0.353 among independent insect.The result of RT-qPCR showed that Ccshsp12.2 was up-regulated by the effect of insecticides and ultraviolet independently.The relative expression of Ccshsp12.2 was 3.36-6.17 times higher than the control under the treatment of insecticides and ultraviolet A radiation.[Conclusion] The phylogenic result and molecular evolution analysis showed that Hymenoptera insects with different living style might suffer from different evolution stress.Ccshsp12.2 was induced in response to ultraviolet and 4 kinds of pesticides.The findings in this study would provide some clues for the investigation about the response of C.cunea to a biotic stresses and insight into the use of this parasitoid in biological control strategies.

[Objective] Trichagalma acutissimae(Hymenoptera:Cynipidae) is one of the important pests harming afforestation plants Quercus variabilis and Q.acutissima(Fagaceae).The pest forms galls and feeds in galls,which is hidden,thus it is very difficult to control the pest by chemical pesticide.However the pest may be effectively controlled by using natural enemies.The present study aimed to determine the species and biological characteristics of natural enemies in the galls of T.acutissimae and provide a scientific basis for the prevention and control of the gall wasp with natural enemies.[Method] In this study,field investigation and indoor anatomy of the galls during wintering and gall growing period were carried out to investigate the species of natural enemies in the galls and their life history and behavioral characteristics of dominant natural enemies.[Result] There were three dominant natural enemies in the gall of T.acutissimae:Torymus sp.(Hymenoptera:Torymidae),Eurytoma sp.(Hymenoptera:Eurytomidae) and Pteromalus sp.(Hymenoptera:Pteromalidae).They all overwintered with larva in the gall of asexual insects.Torymus sp.had two generations a year.The overwintering adults began to appear in early May and oviposited in the asexual galls.The first generation of adults emerged in early July.Eurytoma sp.occurred two generations yearly,overwintered generation adult emerged in early June and laid eggs in the asexual galls.After those eggs developed,the first generation of adults turned up in middle June.Pteromalus sp.had three generations a year.The overwintered generation began eclosion in early April and laid eggs in gall of sexual generation.The first generation of adults arose in the middle of May,and then laid eggs in gall of asexual generation.Afterwards,the second generation of adults began to appear in late June.[Conclusion] The dominant natural enemies in T.acutissimae are Torymus sp.,Eurytoma sp.and Pteromalus sp.,which can be used as biocontrol agents for biological control of larva of T.acutissimae.

[Objective] In order to control the curl deformation and solve the key industrial production technical problems of the new type waterproof plastic membrane enhanced flexible decorative veneer,this study adopts different kinds of decorative veneers to glue with plastic film by hot pressing under different conditions,and with the curl radius of curvature for the characterization of indicators,so as to explore the influence factors of crimped and control mechanism of the plastic film enhanced decorative veneer,and to provide theoretical basis and practical support for the manufacturing and using of the flexible decorative veneer.[Method] Using red oak as experimental material,the paper studied the influences of the hot-pressing temperature,thickness ratio of plastic film and moisture content of decorative veneer on the curl deformation of the plastic film enhanced decorative veneer.And using red oak,rosewood,teak and northeast China ash as materials,the curl deformation of different kinds of decorative veneer species was also studied in this research.[Result] The results show that the effect of hot-pressing temperature is remarkable.The more the hot-pressing temperature increased,the greater the curvature radius of deformation is.With the increase of the thickness of the decorative veneer and the decrease of the thickness of plastic film,the curly curvature radius increase.Therefore,considering the veneer facing production,it is advisable to choose the plastic film thickness of 0.3 mm.The moisture content has miner influence on curl,while the decorative veneer sliced with the big density and compact microstructure wood,can be relatively small with the curling deformation.[Conclusion] The thermal pressure temperature has a significant influence on the curl deformation of the plastic film enhanced flexible decorative veneer.In actual production,it should be considered to reduce the thermal pressure temperature as much as possible to increase the radius of curvature and reduce the crimping deformation.The thickness of the decorative veneer and plastic film has a great influence on the crimped deformation,and the thickness selection should be combined with the specific situation of production,in general,the thicker the thickness of the decorative veneer is and the thinner the thickness of the plastic film is,the smaller the curl will be.This paper provides an important idea for controlling the curling deformation of the double layer thin composite material.

[Objective] The formula for calculating the shear stress of the cross laminated timber (CLT) rectangular beam was explored to provide a theoretical basis for testing the interlaminar shear strength of CLT.[Method] Interlaminar shear strength of three-,five-and seven-layers CLT beams and glulam beams was calculated by Hooke's law and on the basis of the differential relationship between beam's bending moment and shear stress.Shear stress calculation formula of CLT beams was developed,and its distribution characteristics of CLT beams and glulam beams were also compared.[Result] Interlaminar normal stress of CLT beam was interrupted,and shear stress between layers was continuous.Shear stress for rectangular section CLT beams along the height of the section tended to equalize and no longer followed the parabolic distribution.In center-point bending loading for short-span CLT beams,rolling shear failure in vertical layer,interlaminar shear failure and bending failure in parallel layer occurred in turn.The maximum load of the center-point bending load-displacement curve for CLT short-span beams was the interlaminar shear failure load,it was stable and easy to read.Interlaminar shear strength of Hemlock CLT was positively correlated with elastic modulus of parallel layer.[Conclusion] Interlaminar shear stress and the maximum shear stress of CLT beams were related to the number of CLT layers and the ratio of elastic modulus of parallel and vertical layers E_L/E_T(or E_L/E_R).The maximum shear stresses of three-,five-and seven-layers CLT rectangular beams occurred on the neutral axis of the beam section,and their values were 92.8%,86.7%,and 92.6% of the 1.5 times section average shear stress,respectively.Short-span beam three-point bending method was an effective method of testing the interlaminar shear strength of short-span CLT beams.

[Objective] The objectives of this study were to compare the composition,structure,floristic characteristics of two forest communities at adjacent successional stages in the central-subtropical China,in order to enrich information on forest dynamics in subtropical regions,and provide scientific basis for accelerating forest ecological restoration and biodiversity conservation.[Method] By adopting the space-for-time substitution method,and combining Phytocommunity Studies method,two different forest communities,comprising of 45-50 years old Pinus massoniana+Lithocarpus glaber+Loropetalum chinensis conifer-broadleaved mixed forest (PLL) and 80-90 years old L.glaber+Cleyera japonica+Cyclobalanopsis glauca evergreen broadleaved forest (LAG) were selected to represent middle succession stage and successional climax stage in the study region,respectively.Three permanent plots in size of 30 m×30 m were established along the slope in two types of forest communities.All woody plants with diameter at breast height (DBH) larger than 1 cm were mapped,tagged,and identified to species.Community diversity indices,eigenvalue and similarity coefficient were calculated.[Result] In both PLL and LAG communities,the tree species were abundant,a few species appeared to be in absolute dominant,and spatial distribution in the community were uniform.The species richness and species diversity index were obviously higher in LAG than those in PLL.The dicotyledonous plants increased substantially in LAG compared with PLL.The differences of community structure between PLL and LAG reflected in the species composition of trees,especially evergreen broad-leaved species.The canopy of PLL mainly consisted of trees of Pinaceae and Fagaceae,exhibiting the characteristics of conifer-broadleaved mixed forest.However the upper layers of LAG forest were more diverse and mainly composed of various evergreen broad-leaved trees,such as Fagaceae,Lauraceae,Anacardiaceae,Hamamelidaceae,and Alangiaceae,and exhibiting the characteristics of evergreen broad-leaved forest.The vertical stratification on the number of tree species and the number of individual trees was structured into two layers.The species of each layer were more diverse in LAG than in PLL,especially in the (1-5 m) layer and the canopy (higher than 15 m) layer.The DBH structure displayed an inverse"J "pattern,and the individuals were mainly concentrated in range from 1 to 8 cm of DBH in both PLL and LAG forests.The number of species and the number of individual trees of middle and large diameter classes were more in LAG than in PLL.In the PLL,P.massoniana was degrading due to the poor regeneration under forest,meanwhile,L.glaber and L.chinensis became dominating,reflecting succession direction from PLL to LAG.I the LAG degradation of P.massoniana was obvious,L.glaber and C.glauca became dominating,and C.lanceolata was relatively stable.The flora of the PLL and the LAG were mainly Pan tropical distribution of tropical elements,with clear transition from tropics to temperate.There were more tropical families,genera and species in the LAG than in the PLL.[Conclusion] There were significant differences in the species composition and community structure between the PLL and the LAG.The study indicated that vegetation restoration in subtropical region should follow the succession dynamics of the community.For the P.massoniana conifer-broad leaved mixed forest at the middle succession stage,we should close hillsides for reforestation to allow its natural succession or use artificial intervention such as replanting of evergreen broad-leaved tree species,in order to shorten the duration of restoration,establish reasonable tree species composition and improve stand quality.By using the LAG as a basis,it was necessary to strengthen the utilization of the Pan-tropical distributed plants,and select broad-leaved tree species with similar origins and successions as the dominant species in the improvement of secondary forest or" conversion conifer forest to broadleaved forest".

[Objective] Mycorrhizal fungi can promote plant growth,and improve plant resistance to stresses.Thus,mycorrhizae have greatly application potential in forestry.In this study,our aims are to:(1) explore the rational application of mycorrhizal fungi in the cultivation of Fraxinus mandshurica seedlings.(2) investigate the effects of single and mixed inoculations on the growth of F.mandshurica seedlings in light culture media.[Method] Six inoculations (Glomus mosseae,Glomus etunicatum,mixed inoculation of Glomus mosseae and Glomus etunicatum,humus from Larix gmelinii,F.mandshurica,and their mixed stands,respectively) were used to cultivate F.mandshurica seedlings on light culture media,with non-mycorrhizal seedlings as CK.Effects of inoculations on the root development and seedling growths of F.mandshurica cultivated in light culture media were investigated over the growth season.[Result] Results showed that the inoculations were able to promote the growth of F.mandshurica seedlings and improve the seedling qualities.Mixed inoculations had better effects than the single ones and the control.The seedling height under G.mosseae and G.etunicatu mixed treatment was 31.22% higher than the CK.Basal diameters and leaf areas of seedlings inoculated by humus from the mixed stands were 21.52% and 55.13% greater than the CK,respectively.Mycorrhizal inoculations were able to increase the biomass of the roots,stems and leaves of F.mandshurica seedlings cultivated in light culture media.Seedling biomass of the seedlings by the mixed inoculation of G.mosseae and G.etunicatu increased much more than that of seedlings with single inoculation (i.e.,G.mosseae and G.etunicatu,respectively).Mycorrhizal inoculation promoted root growth of F.mandshurica seedlings by increasing their root diameters,root superficial areas,root volumes,numbers of root apexes,cell diameters,vascular diameters and layers of cortex parenchyma.[Conclusion] Mycorrhizal inoculation obviously promoted the growth of F.mandshurica seedlings cultivated in light culture media.Compared with single inoculation,the mixed inoculation of G.mosseae and G.etunicatu and Larch and ash mixed stand humus showed better effects on the seedlings.

[Objective] In this study,the essential oils were extracted from leaves of five native Phoebe plant species in Jinyun Mountain and their volatile components were identified.Furthermore,their composing differences were analyzed and the genetic relationship was explored in order to provide basis data for classification and exploitation and applications of the native Phoebe plant resources of Chongqing.[Method] According to the representative principle,the leaf samples were collected in early July when the annual photosynthetic efficiency of leaves is the highest.The essential oils were extracted through the steam distillation,and the volatile components were separated by GC-MS and identified through automatically retrieval from NIST 2008 libraries assisted by manual analysis.Then SPSS19.0 software was applied to conduct the Principal Component Analysis (PCA) and the Hierarchical Clustering Analysis (HCA) for the five species.[Result] The extraction rates of the leaf essential oils from the native Phoebe plant resources were 0.313 5%,0.003 6%,0.096 4%,0.075 3% and 0.070 7%,respectively.The essential oil yield of Phoebe neurantha(Hemsl.) Gamble leaves was the highest,Beilschmiedia yaanica N.Chao took second place and Phoebe sheareri(Hemsl.) Gamble var.omeiensis(Yang) N.Chao was the lowest.P.neurantha was 87 times more than P.sheareri var.Omeiensis.Measured by GC-MS,a total of 187 volatile components were isolated from the five kinds of leaves essential oils.Among them,P.neurantha contained 78 components,the main ingredients were Varidiflorene (2.911 0 μg·g^-1),δ-Cadinene (2.042 3 μg·g^-1) and α-Cadinol (1.634 9 μg·g^-1).P.sheareri var.omeiensis contained 62 components including n-Hexadecanoic acid (0.230 4 μg·g^-1),Linoleic acid (0.076 3 μg·g^-1) and Phytol (0.005 86 μg·g^-1).B.yaanica contained 79 components including α-Pinene (1.687 1 μg·g^-1),δ-Cadinene (1.316 0 μg·g^-1) and Bornyl acetate (1.249 2 μg·g^-1).B.kweichowensis contained 79 components,including α-Pinene (1.607 5 μg·g^-1),δ-Cadinene (1.448 7 μg·g^-1) and Copaene (1.393 9 μg·g^-1).M.lichuanensis contained 54 components,including 13-Tetradecenal (6.495 7 μg·g^-1),Tetradecanal (2.375 4 μg·g^-1) and Decanal (0.934 7 μg·g^-1).According to those types of compounds,the volatile components of essential oils from the five native Phoebe plant leaves mainly belong to olefins and alcohols.In addition,there were esters,alkanes,aldehydes,naphthalene,ketones,organic acids,benzene and many other types of compounds.However there were only seven common ingredients among all the five samples.According to the PCA and HCA analyzing,the five species of Phoebe were obviously divided into three categories.B.yaanica was similar with B.kweichowensis in the composition and contents of the volatile components.Therefore,they were classified into the same category.P.sheareri var.Omeiensis and M.lichuanensis were grouped into another category.However,P.neurantha was classified into one category because of its obvious difference from others.[Conclusion] The main volatile ingredients of leaf essential oil from five native Phoebe plant resources belong to olefins and alcohols and there is obvious differences among the five species.Meanwhile,The results of chemical taxonomy of essential oils from leaves are different from those of traditional morphology.