Objective: To explore the patterns of evolution of ground surface temperature in urban area,quantitatively explain the difference in vegetation cooling under different vegetation coverage conditions and provide a basis for improving urban ecological environment and rational planning of urban green space. Method: The study was focused on the highly urbanized area within the 5^th ring road in Beijing. We divided the study area into extremely low temperature zone,low temperature zone,sub-low temperature zone,medium low temperature zone,sub-high temperature zone,high temperature zone and extremely high temperature zone and then explored the spatial and temporal changes of ground surface temperature during 1999-2017 based on the ground surface temperature and vegetation coverage images from the five-phases Landsat remote sensing images. Linear regression was used to further analyze the correlation between vegetation coverage and surface temperature at 300,600,900 and 1 200 m grid scales. Result: From 1999 to 2017, the temporal change of the thermal environment within the 5^th ring road in Beijing is divided into two stages. The area of the high temperature zone and the extremely high temperature zone gradually increased from 1999 to 2011, and the thermal environment has improved from 2011 to 2017 The area proportions of the high temperature zone and the extremely high temperature zone decreased by 0.96% and 0.71%,respectively,and the those of the extremely low temperature zone and the low temperature zone increased by 0.45% and 1.19%,respectively. The spatial pattern of the thermal environment changed significantly with the urban development of Beijing. In 1999, zones with high annual surface temperatures are concentrated within the 2^nd ring road,and gradually transferred outward after 1999. By 2011, high temperature and extremely high temperature zones were concentrated in the area south of the center between the 3^rd and the 5^th ring road (the area proportions of the high- and extremely high-temperature zones reached the highest,70.73% and 78.92%,respectively). The overall thermal environment within the 5^th ring road has improved in 2017. During the study period,the vegetation coverage of the whole study area generally showed a decreasing-to-increasing trend with the lowest value of 31.84% in 2005. The zones with high vegetation coverage are mainly distributed in the area between the 4^th and 5^th ring roads. We observed the overall negative correlation between the surface temperature and the vegetation coverage (P < 0.001). Moreover,this relationship is significant under the condition of 40%-60% vegetation coverage at all grid scales throughout the study period. Moreover,the cooling effect increased with the vegetation coverage when compared with the same grid scale. Conclusion: The areas of high temperature and the extremely high temperature gradually increased from 1999 to 2011. The high temperature area continued to transfer outward from within the 2^nd ring road,while the thermal stress was alleviated during 2011 to 2017. The vegetation coverage generally decreased first and then increased,and the vegetation coverage was higher between the 4^th and the 5^th ring roads. The increase in vegetation coverage can reduce the ground surface temperature,and a stable cooling effect is shown when the vegetation coverage reaches 40%-60%. Therefore,it is plausible to alleviate the urban thermal stress by appropriately increasing the vegetation coverage and improving the cooling effect of urban green space.

Objective: The application of Kalman filter in the resistograph drilling resistance sequence was studied. The resistograph stationary Kalman filter was derived,which provided a method and basis for estimating the age of standing trees. Method: Taking Larix principis-rupprechtii in Yangjuangou forest farm of Shanxi Province as the research object,323 sets of drilling resistance series obtained by resistograph drilling L. principis-rupprechtii in the same horizontal position and different directions were used as the research samples,and 104 stem discs were taken within 5 cm of the drilling position as reference samples. The general Kalman filter theory was applied in resistograph. By analyzing the characteristics of the filter,the parameters were simplified,and the stable Kalman filter was derived. The drilling resistance data obtained through the resistograph drilling into larch was used as input of stationary Kalman filter,and the output was the optimal estimation sequence based on the minimum mean square error as the best criterion,and the tree age was determined by the number of peaks and troughs of the optimal estimation sequence. The results estimated by the stationary Kalman filter algorithm,or auto-recognized by DECOM software were analyzed with the corresponding number of disc rings using paired data t-test. Result: The resistograph stationary Kalman filter reduced the number of initial parameters,the optimal estimation sequence of drilling resistance value only depended on parameter Rat. When the appropriate parameter Rat was selected according to their DBH size,the resistograph stationary Kalman filter applied in 323 groups of drilling resistance standing had better denoising effects,so that the algorithm estimating tree age was closed to the actual age. The relative error distribution of the algorithm was mostly between -10% and 10%,the minimum relative error was 0%,the maximum relative error was 25.69%,and the average relative error was 0.75%. Through paired data t-test,it was found that t-value was -0.468 16,indicating that there was no significant difference between the mean age estimated by the algorithm and the true mean age of trees. The relative error of the automatic analysis by DECOM software was large,mostly concentrated between -20% and -60%. The minimum relative error was -7.69%,the maximum relative error was -84.78%,and the average relative error was -40.49%. Through paired data t-test,it was found that t-value was 20.254,indicating that there was significant difference between the mean age estimated by DECOM software and the mean tree age of trees. Conclusion: The method of applying the resistograph stationary Kalman filter to the drilling resistance data sequence could accurately estimate the age of L. principis-rupprechtii,which might be better than the automatic analysis by DECOM software. This method is small invasive,fast and high accuracy,which provides an effective way for estimating the age of standing L. principis-rupprechtii.

Objective: The classification of bamboo forest,coniferous forest and broad-leaved forest using visible data acquired by unmanned aerial vehicle(UAV) remote sensing could expand the application scope of UAV visible light remote sensing data in forest resource survey. Method: The aerial image acquired by UAV only containing the red,green and blue three-band information was preprocessed to generate digital orthophoto map(DOM)and digital surface model(DSM)with a spatial resolution of 0.1 m. Six categories of features were extracted from DSM and DOM,including height features,spectral features,common vegetation indices,HSV color components,texture features extracted based on HSV color component,and extended morphological multi-attribute profiles(EMAPs). Random forest_recursive feature elimination(RF_RFE)was used to determine the optimal feature set. Eight groups of experiments were constructed according to different types of features and selected feature subsets,and then the forest stand were classified by random forest classifier(RFC). The evaluation classification results of confusion matrix were established using real ground images obtained by interpretation. Result: 1) Forest stand classification using spectral characteristics alone was not satisfactory,the overall accuracy was 65.68%,and the Kappa coefficient was 0.53. Based on the spectral features,other features could be introduced to improve the overall accuracy except vegetation indices. 2) Among the 11 features optimized by the RF_RFE,there were 5 EMAPs features,3 HSV texture features,1 height feature,1 vegetation index and 1 HSV color component. These 11 features obtained the highest classification accuracy in 8 groups of experiments,with an overall accuracy of 81.05% and a Kappa coefficient of 0.73. 3) A good classification result could be obtained by applying the multi-feature preferred method to the visible light drone images of different resolutions. When the resolution was 0.3 m,the classification accuracy was the highest,the overall accuracy was 82.46%,and the Kappa coefficient was 0.75. Conclusion: The research showed that the RF_RFE algorithm could synthesize the most favorable features of multi-type features in forest stand type classification,and thus improve the classification accuracy. This study could provide a reference for the extraction of forest stand information in forest resource inventory.

Objective: Based on the maximum entropy model (MaxEnt),the risk of rubber tree root disease in China under the background of future climate change was predicted,and the major environmental factors affecting the occurance of the disease were analyzed. This study is of great significance to the quarantine and control decision of rubber tree white root in China. Method: This study was based on previous studies on the occurrence and prevalence of white root disease of rubber trees (Hevea brasiliensis). We selected the geographical distributive information and primary environmental factors influencing the occurrence of this disease with global bioclimatic data and disaster data in baseline (1970-2000),and constructed a correlation model between the occurrence of this disease and primary environmental factors by using MaxEnt model and geographic information system (GIS). Based on five global climate models (GCMs) provided by the coupled model inter comparison project phase 5 (CMIP5),integrated with equal weight set average method,the climate prediction data of 2050s (2041-2060) and 2070s (2061-2080) for representative concentration pathway (RCP)2.6,RCP4.5 and RCP8.5 emission scenarios were obtained. According to the established model,we predicted baseline and future (2050s and 2070s) risk area distribution of this disease,analyzed the influence of climate change on risk area distribution of this disease,and identified prevention and management key and sensitive areas in the future. Result: The average area under curve (AUC)of the receiver operating characteristic (ROC) from model training and testing data was 0.965 and 0.942. The results of simulation and prediction were basically consistent with the historical disaster situation. The major environmental factors with higher contribution rate were variation range of annual mean temperature,precipitation in the wettest month,monthly mean difference in temperature between day and night,mean temperature in the coldest quarter,the standard deviation of temperature seasonal variation,and the lowest temperature in the coldest month. During the baseline,the high risk areas of this disease were mainly concentrated in Hainan Island,southwest and southeast parts of Guangdong Province,south and southeast parts of Yunnan Province. From baseline to future,the centroid position of the risk area of this disease moved to the northeast in China. The proportion of the high risk areas of this disease would increase. Conclusion: The risk area of rubber tree white root disease is significantly affected by temperature and precipitation. The key areas for prevention and management of this disease are Hainan Island,south parts of Yunnan province,southwest parts of Guangdong province. The sensitive areas are part of southeast Guangxi province,part of eastern Guangdong province,part of southern Fujian province in China. The study could provide a reference for the inspection and quarantine of this disease in China.

Objective: This study aims to investigate the variation patterns of latex yield and physiology during the occurrence and development of tapping panel dryness (TPD) induced by ethephon overstimulation in rubber tree (Hevea brasiliensis), so as to provide a theoretical basis for making better use of ethephon to stimulate latex production and taking effective measures to prevent the occurrence of TPD. Method: In this study, the healthy plants of rubber tree clone 'Reyan 7-33-97' were used to induce different grades of TPD by overstimulation of tapping with ethephon, and the change patterns of latex yield and related physiological indexes of plants with different grades of TPD were compared and analyzed, including pH, lutoid bursting index, dry rubber content, total solid content, thiol content, inorganic phosphorus content, the size distribution and average size of rubber particles. Result: 1) During tapping with ethephon overstimulation, the latex yield showed a trend of rising first and then falling. The yield increased continuously by more than three fold in the early stage. However, the TPD was soon induced. With the occurrence and development of TPD, the latex yield decreased gradually and finally became lower than that of healthy plants. 2) The lutoid bursting index increased significantly with the severity of TPD, the ruptured lutoid then resulted in blockage of the laticifers. This phenomenon was directly related to the occurrence of TPD. The latex pH values of TPD plants also increased slightly, but only the pH value of grade 3 TPD plants showed a significant difference from that of healthy ones. 3) Ethephon overstimulation had a dilution effect on latex. The contents of latex dry rubber and total solid in latex of TPD plants were lower than those of healthy ones. The contents decreased gradually in grades 2-3 TPD plants, and then recovered gradually in grades 4-5 TPD plants. 4)The thiol contents were significantly increased in grades 2-3 TPD plants, but gradually decreased to nearly normal levels in grades 4-5 TPD plants. In grades 2-5 TPD plants, the inorganic phosphorus contents showed a decreasing trend, but all showed higher than the healthy plants. 5) The size distribution of latex rubber particles of healthy plants ranged from 0.09 to 2.27 μm with a single peak. With the occurrence and development of TPD, the size distribution gradually moved to the direction of small size, and the peak value also decreased. Consistent with that, the average size of rubber particles became smaller with the increase of TPD grade. The average particle sizes of grades 2-5 TPD plants were significantly lower than that of healthy ones. The average particle size of healthy plants was 0.89 μm, while that of grade 5 TPD plants was only 0.79 μm. Conclusion: Over stimulation of tapping with ethephon will result in an increase in the burst of lutoid, outflow of a large amount of thiol and inorganic phosphorus, and the decrease of rubber particles, which will lead to the damage and blockage of the laticifer system, affect the rubber biosynthesis and latex flow, and finally show the symptoms of TPD. In the production of natural rubber, ethephon stimulation should be reasonably used, avoiding excessive stimulation to induce TPD which always results in yield reduction.

Objective: The study was aimed to investigate the effects of fluoride and bicarbonate on the growth and carbon metabolism of Broussonetia papyrifera seedlings,and to reveal the mechanism of the effects of fluoride ions on plant photosynthesis and sugar metabolism in karst ecological region,in order to provide a theoretical basis for forest vegetation management and restoration in fluorine rich areas. Method: B. papyrifera seedlings were treated with Hoagland nutrient solution added with NaF and NaHCO₃ in 4 ways: control,3 mmol·L^-1 NaF,3 mmol·L^-1 NaHCO₃ and 3 mmol·L^-1 NaF+3 mmol·L^-1 NaHCO₃. The growth parameters,photosynthetic parameters,phosphofructokinase(PFK),glucose-6-phosphate dehydrogenase(G6PDH) and carbonic anhydrase(CA) enzyme activities of B. papyrifera seedlings were measured. Result: 1) Addition of F^- significantly inhibited the growth and photosynthetic capacity of plants,and transferred glucose metabolism from glycolysis pathway to pentose phosphate pathway. When HCO₃^- was not added at the same time,F^- had no significant effect on CA activity in leaves; but when HCO₃^- was added at the same time,F^- significantly inhibited CA activity in leaves. 2) Rhizospheric HCO₃^- significantly promoted plant growth and photosynthetic capacity,increased total glucose metabolism and CA enzyme activity. However,F^- inhibited the positive effects of HCO₃^- on plants,consequently significantly reduced growth,photosynthesis and glucose metabolism,but significantly increased G6PDH activity. Conclusion: In conclusion,the higher concentration of F^- in the environment significantly inhibits the growth of B. papyrifera seedlings,and its adverse effects on the growth of B. papyrifera are reflected in the inhibition of photosynthetic process and the distribution of excessive carbohydrate metabolic substrates to pentose phosphate pathway. The appropriate amount of rhizospheric HCO₃^- provides additional photosynthetic metabolic substrate for plant growth,and improves the glucose metabolism level of plants,which improves the stress resistance and growth ability of plants. Under the HCO₃^- and F^- treatment,the favorable effect of HCO₃^- on plant growth was reduced by F^-,mainly due to the destruction and inhibition of the structure and activity of various enzymes in plant photosynthetic system,and it may also be related to the competition between HCO₃^- and F^- during root absorption.

Objective: The aim of this study was to evaluate growth and stability of clones (varieties) of Populus Section Aigeiros, and discrimination and representativeness of each trial sites of the regional clonal trials based on BLUP and GGE (genotype main effect plus genotype-environmental interaction effect) biplot,and provide the theoretical basis for selection and application of the introduced clones. Method: DBH and height of 15 clones at 9 trial sites were measured at age of 6 years,linear mixed models (LMM) with site as fixed effect and clone,clone by site interaction as random effects were to be used for best linear unbiased prediction (BLUP) analysis. Then BLUP data of DBH and height for each clone at each site were obtained to conduct GGE biplot for evaluating these introduced clones and regional trial sites. Result: The first two principal components (PC1 and PC2) of GGE biplot explain respectively 84.69% and 69.83% of the variance based on BLUP data of DBH and height. GGE bioplot based on BLUP data of DBH showed that the 9 trial sites were positively correlated with each other. The 9 trial sites were divided into 2 groups: Yongqing of Hebei and Jinxiang of Shandong in a group,with the largest DBH of clone 50,and the other 7 sites in another group,with the largest DBH of clone Por. Changping of Beijing and Yongqing of Hebei were the most discriminative sites,while Ningyang (Gaoqiao) of Shandong and Weixian of Hebei were the most representative sites. The clone Por had the largest DBH,followed by the clones Pa,36,108,50,111,and 107,all of which were larger than the average. The clone Og had a DBH close to the average,and the clone La showed the smallest DBH,the clones 107,Me,108,Br,Og and 36 displayed a better stability. Conclusion: GGE biplots based on BLUP data of DBH and height were different,and the GGE biplots of DBH were more reliable than that of height. The clone Por had the largest DBH followed by Pa,36,108,50,111 and 107. The clones 107,Me,108,Br,Og and 36 showed a better stability with DBH. Comprehensively,the clones Por,Pa,36,108 and 107 showed both better stability and fast growth.

Objective: To establish a safe and antibiotic-free genetic transformation system of Lespedeza bicolor. Using genetic engineering technology to improve the tolerance to abiotic stress of L. bicolor. Method: The coding sequence of xylose isomerase gene (xylA) was cloned from Escherichia coli DH5α strain by PCR amplification. The pBI121-xylA-BADH plant expression vector with xylA & betaine aldehyde dehydrogenase gene (BADH) was built. The xylose selection system of L. bicolor was built by using xylose instead of a certain amount of sucrose in the mediums. The cotyledonary node explants of L. bicolor were transformed by using the Agrobacterium tumefaciens-mediated method. The transgenic plants were confirmed by PCR amplification and Southern blot analysis. The growth performance of transgenic and wild-type plants under 0.5-2 g·L^-1 NaCl stress was measured. The betaine aldehyde dehydrogenase activity,contents of chlorophyll and conductivity of transgenic and wild-type plants in vitro under 1.0 g·L^-1 NaCl stress were assayed. The total soluble sugars were extracted separately from the leaves of wild-type plants and transgenic plants in vitro. The sugars were assayed by high performance liquid chromatograph. Result: After DNA sequence analysis,the homology is up to 100% between the cloned product and the published xylA DNA sequence from E. coli in GenBank. The PCR products and restriction enzyme digestion assays showed the pBI121-xylA-BADH plant expression vector was correctly constructed. In the transformation of L. bicolor,the selective mediums for regeneration of adventitious buds from cotyledonary nodes should be the medium which contained xylose as the sole carbon resource,while the selective mediums for shoot segment multiplying or rooting should be the mediums which contained 5 g·L^-1 sucrose and 25 g·L^-1 xylose. In Agrobacterium-mediated genetic transformation,the explants were precultured for 1 day,then infected with LBA4404 strain for 20-30 min,and cultured with Agrobacterium tumefaciens for a total of 3 days,relatively more xylose-resistant buds were obtained. Some xylose-resistant buds were assayed by PCR amplification and Southern blot analysis. Two transgenic lines were obtained. The genetic transformation rate of L. bicolor was lower than 4.7%. The growth performance of transgenic and wild-type plants under NaCl stress showed that the transgenic plants grew and rooted normally in the medium containing 2 g·L^-1 NaCl,while the wild-type plants defoliated after leaves turning into yellow,and were unable to root. BADH activity,the contents of chlorophyll and conductivity showed no significant differences between the transgenic and wild-type plants under no NaCl stress. There was no significant change of the BADH activity in wild-type plants when they were treated with NaCl or without NaCl. The BADH activity in transgenic plants increased greatly and up to 8-10 times as high as the wild-type plants when treated with NaCl. The transgenic plants had significant higher contents of chlorophyll and lower conductivity than the wild-type plants under NaCl stress. The assay on total soluble sugars by the high performance liquid chromatograph showed there were fructose and glucose in transgenic plants,while there were glucose and an unlabeled saccharide without standard sample in wild-type plants. Conclusion: The genetic transformation system of L. bicolor under xylose selection system was established. The transgenic plants with stable expression were obtained. The introduction of exogenous betaine aldehyde dehydrogenase gene increased the tolerance of L. bicolor plants to NaCl stress. The introduction of exogenous xylose isomerase gene from E. coli affected the glycometabolism of L. bicolor plants.

Objective: Based on transcriptome sequencing data,SSR markers of Melia azedarach were developed to provide theoretical and scientific basis for breeding,evaluation and genetic improvement of M. azedarach. Method: The transcriptome of M. azedarach leaves was sequenced by Illumina HiSeq^TM 2500. The transcriptome data was assembled,sequenced and analyzed by the Trinity and MISA software. Using the Primer 3 software,100 pairs of SSR primers were designed and synthesized. The 2% agarose gel electrophoresis and PAGE gel electrophoresis were used for preliminary screening and polymorphic screening. Result: A total of 20 077 unigenes were assembled and clustered based on the transcriptome sequences. The average length of unigenes was 1 431.82 bp and N50 was 1 955 bp. Simple Sequence Repeats (SSRs) were further analyzed in the sequences of unigenes,and 5 469 SSRs from 4 116 unigene sequences (20.50% of total) were identified. The average distribution distance of SSRs was 8.74 kb. The analysis of repetition types indicated that mononucleotide repetition was the main one,accounting for 50.23%,followed by dinucleotide (24.43%) and trinucleotide (22.11%). In SSR repeat units,6-10 repeats were the most,accounting for 51.27% of the total. 16 pairs of polymorphic primers were screened and amplified by PCR. A total of 56 alleles were detected with an average of 3.5 alleles and 2.31 effective alleles per locus. The average Shannon's diversity index (I) and the average polymorphism information content (PIC) were 0.861 and 0.507,respectively. Conclusion: The frequency of SSR loci,the distribution density and repetition frequency of SSR in transcriptome of M. azedarach were all at a high level. A total of 16 primer pairs developed in this study further enriched the existing SSR markers of M. azedarach,which are valuable for further studies on genetic diversity and molecular breeding of M. azedarach.

Objective: This study aimed to seek a new technology with high efficiency and environmental protection for treating the infected wood of pine wood nematode. Through indoor and field experiments,we screened wood-rot fungi that can effectively degrade the infected trees by pine wood nematode and inhibit the movement of pine wood nematodes in the diseased trees,which would provide basis for the development of new ways to eliminate pine wood nematode infected trees. Method: A total of 19 wood rot fungi were initially screened from the decaying pine samples using selective medium. Approximately 2 000 pine wood nematodes were co-cultured on different kinds of wood rot fungi,and the strains that could inhibit the growth and reproduction of Bursaphelenchus xylophilus were screened out. The decomposing ability of wood rot fungi to pine was determined by measuring the weight loss rate of Pinus thunbergii infected by wood rot fungi. A field experiment was carried out to select the strains which can effectively inhibit the propagation of B. xylophilus and degrade pine wood. The nematode-infected trees were inoculated with the liquid shaking culture mycelium. After four months of treatment,the number of pine wood nematodes in the whole section of the infected trees was analyzed. From May to June,the wood samples (0.5-1 cm) around the pupal chamber of longicorn beetles were collected to analyze the number of B. xylophilus in the wood samples around the pupal chamber. At the same time,the eclosion longicorn beetles were regularly captured in the wire mesh cover to analyze the number of nematodes carried by the eclosion longicorn. Result: Seven strains of wood rot fungi with strong ability to inhibit the propagation of B. xylophilus and degrade wood were screened out in the laboratory. After 8 days of culture on the plate of strain J5-2 out of the 7 strains,only 18±10 nematodes were isolated from each plate,while no B. xylophilus was isolated from the plates of Laetiporus sulphureus and Pleurotus ostreatus. Among the tested strains,L. sulphureus had the strongest ability to degrade pine wood. After 4 months of infection,the weight loss rate of samples reached 22.82%,followed by strain S4,which caused 21.68% loss of wood block weight. The field experiment showed that the number of B. xylophilus in infected wood was reduced after inoculation with 7 kinds of wood rot fungi for four months. Strain J5-2,L. sulphureus and strain S4 were able to reduce the number of nematodes in pupal chamber by more than 65%,and the number of nematodes carried by longicorn beetles was less than 200 per head. Strain J5-2 had the best killing effect and reduced the number of nematodes by 72%. The average number of B. xylophilus per longicorn beetle was only 15±4,and the maximum carrying capacity was only 60. Strain J5-2 was identified as Ceriporia. Conclusion: Strain J5-2,L. sulphureus and P. ostreatus have obvious inhibition effect on B. xylophilus. L. sulphureus and strain S4 have strong ability to degrade wood. After treatment,strain J5-2,L. sulphureus and S4 have the best effect,and they can reduce the number of nematodes by more than 65%. The utilization of wood rot fungi is a promising way to deal with pine wood nematode-infected wood in situ,which is worthy of further study.

Objective: This study aims to understand the harmfulness of bark beetle,Tomicus minor,and the stress response of Pinus yunnanensis var. tenuifolia,and explore the relationship between the response and metabolic volatiles related to resistance so as to put forward effective control measures. Method: The induced volatile substances of the pine were studied by headspace solid phase microextraction-gas chromatography/mass spectrometry with the shoots in different damage degrees in Yachang Forest Farm,Leye County,Guangxi. The optimum conditions of SPME were as follows: equilibrium for 15 min on solid phase extraction instrument at 75℃ and extraction for 15 min with 75 micron extraction head (DVB/CAR/PDMS). Result: The most volatile components were detected in severely damaged shoots,mainly terpenes and alcohols. The main metabolic volatile products of the pine were closely related to its damage degree. With the increase of the damage degree,the contents of α-pinene,3-pinene,β-caryophyllene and β-picengene increased,while the content of β-pinene decreased gradually,and only a small amount of longifolene was found in the control. In severely damaged shoots,β-pinene content was the lowest,only 47.85% of the control,while 3-pinene increased the most,higher than 62.83% of the control. The total amount of monoterpenoids and sesquiterpenoids oxygen-containing derivatives increased with the degree of damage,indicating that the insect resistance decreased with the increase of oxygen-containing compounds. Conclusion: The differences in the contents of 3-carene,β-pinene,β-elemene,β-caryophyllene and β-bichenylsolanee are the main reasons for inducing resistance of the pine to the bark beetle in transverse pits.Headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) is suitable for the rapid analysis of volatile components in the pine needles,and this study provides a scientific basis for the study of induced resistance substances of Tomicus minor.

In the present paper,a new species of Diprionidae,Neodiprion qinghaiicus Wei,Wang & Wu,sp. nov.,damages needles of Picea crassifolia from Qinghai Province,China. This species is very similar in the lancet and penis valve to N. wilsonae (Li & Guo,1999) but differs from the latter by the following characters: antenna yellow with black flagellar dents and ventral length of first and second flagellomeres equal in length (versus N. wilsonae antenna entirely black,ventral length of second flagellomere longer than ventral length of first flagellomere); In hind wing,length of inner part of cell 1 M basad vein cu-a is clearly longer than outer part of cell 1 M beyond vein cu-a (the two parts equal in N. wilsonae); The body of the insect is narrower (body robust in N. wilsonae). The new species can be recognized from its congeners by the black head and yellow abdomen. A key to Chinese Neodiprion species is provided.

Objective: In this study,the temporal and spatial patterns of forest fires caused by lightning,agricultural fire and smoking fire were analyzed based on the historical data of forest fires in Heilongjiang Province,which would provide scientific basis for management of forest fires in this area. Method: Based on the data of forest fires in Heilongjiang Province from 1997-2017, the temporal variations of three fire sources were analyzed respectively. The differences of the total fire areas caused by three fire sources in different months and days were analyzed by two factor analysis of variance. The spatial distribution patterns of three fire sources were analyzed by multi distance spatial clustering analysis (Ripley's K function). Result: From 1997 to 2017, the forest fires caused by lightning fire were the most frequent and harmful among the forest fires in Heilongjiang Province,and the number of the occurence increased in recent years. Lightning fire occurred mainly in Daxing'anling area,and most frequently in June and July. However,the average area of forest fires caused by lightning was the largest from 16:00-16:59 in September every year. The frequency and total area of the other two forest fires (caused by agricultural fire and field smoking) mainly occurred in April and May,showing a fluctuating decline from 1997-2017. The agricultural fire-caused maximum forest fires (average area) annually occurred from 12:00-12:59 in June and from 16:00-16:59 in September. However,there was no difference in the total area of fire sites caused by smoking fire over months and days in the field,indicating that fire prevention should be focused on the fire source in the time of high frequency and high degree of harm. From the perspective of space,agricultural fire mainly occurred in Heihe municipal district,Nenjiang County,sunke County and Qitaihe City; smoking fire mainly in Songling Forestry Bureau,Jiagedaqi Forestry Bureau,Xunke County,Jiayin County,Qitaihe City and Jidong County. Conclusion: With the gradual strengthening of fire source control,forest fire monitoring and fighting capacity in Heilongjiang Province,a total area of forest fires (including lightning,field smoking and agricultural fire) has decreased significantly in recent years compared with that before. Most of the forest fires occur in spring and summer. The forest fires caused by the three fire sources are mainly concentrated in Daxing'anling area in the northwest,Heihe and Yichun in the North and Qitaihe in the southeast.

Objective: The acoustic vibration properties of commonly used string musical fretboard wood were comprehensive analyzed and summarized, which could be the basis for the search of alternative wood or modification of fast-growing wood. Method: The X-ray profile densitometer was used to characterize the density differences between the earlywood and latewood in a growing ring and their uniformities along the radial density distribution. The ultrasonic microsecond meter was used to test the sound propagation speed of the wood. The vibration frequency, torsional frequency and damping ratio of wood were tested by modal analysis method. The acoustic vibration performance parameters of wood were also calculated according to the Euler-Bernoulli equation of rectangular section. Result: The oven dry density of fretboard wood was 1 180 kg·m^-3 for ebony(Diospyros crassiflora), 810 kg·m^-3 for Indian rosewood(Dalbergia latifolia), 1 320 kg·m^-3 for African blackwood(Dalbergia melanoxylon), 660 kg·m^-3 for the hardwood hard maple(Acer saccharum) string instrument soundboard and 480 kg·m^-3 for non-instrumental wood radiata pine, respectively. The density differences of fretboard wood between the earlywood and latewood in the growth ring and between the adjacent growth ring were not significant, and had a uniform texture. The sound propagation velocity of the fretboard wood was lower than that of hard maple and radiata pine in axial and radial direction. The sound propagation speed ratio of parallel grain to vertical grain of hard maple was 3.2, which was the maximum value. The acoustic anisotropy of hard maple was much better. The dynamic modulus of elasticity(E')of ebony, African blackwood and Indian rosewood were 18.2, 16.8 and 14.8 GPa, respectively, which indicated that the dynamic modulus of elasticity of fretboard wood was greater than 14.0 GPa. The specific dynamic modulus of elasticity (E_sp) of fretboard wood was less than 18.0 GPa, those of hard maple and radiata pine were 24.5 and 26.8 GPa, respectively, which were all higher than the E_sp of fretboard wood. The acoustic radiation quality constants(R)of ebony, Indian rosewood, African blackwood, hard maple and radiata pine were 3.21, 5.08, 2.58, 7.17 and 9.41 m³·Pa^-1s^-3, respectively. The acoustic impedance(ω), logarithmic attenuation coefficient(λ)and loss tangent(tanδ)of ebony, Indian rosewood and African blackwood were all higher than those of hard maple and radiata pine. The ratio of acoustic conversion(ACE)to E'/G' of fretboard wood was lower than that of hard maple. The dynamic shear modulus(G')of ebony, Indian rosewood, African blackwood, hard maple and radiata pine were 1.97, 1.72 and 2.58, 1.21 and 1.09 GPa, respectively, which were higher than those of hard maple and radiata pine. Conclusion: The oven dry density of fretboard woods are larger than 800 kg·m^-3. There might be a functional relationship between wood density and acoustic vibration performance parameters of wood. When selecting materials, density and acoustic vibration performance should be considered simultaneously. In terms of acoustic vibration performance, E' and G' could be the main evaluation indicators of wood acoustic vibration when selecting materials, and it should be required to select the wood with high E' and G' values as much as possible. The higher the E' value, the stronger the resistance to bending deformation caused by different string tensions. The greater the G' value, the stronger the ability of the fretboard to suppress torsional deformation under the action of different string tensions. The acoustic vibration parameters of wood such as E_sp, R, ACE, E'/G', λ, tanδ and ω might be not the important evaluation indicators for fretboard selection.

Objective: In order to effectively improve the accuracy and speed of wood identification, a new method of wood identification based on PWoodIDNet model, a convolutional neural network model, was proposed with expects to provide advanced identification method and instruments for customs, import and export quarantine inspection, furniture enterprises and other legal departments and enterprises, and to promote the scientific and technological progress of China's wood import and export quarantine inspection industry and wood processing and manufacturing enterprises. Method: Firstly, 16 kinds of wood samples were selected, and 50 high-resolution microscopic CT images and industrial camera images were obtained from each sample with a total of 1 600 images. Then, a total of 4 800 target regions with wood rays, parenchyma, axial tracheids, pits and textures were intercepted. The image set was expanded to 19 200 images through image enhancement algorithms, such as horizontal flipping, vertical flipping, mirroring and brightness transformation. The PWoodIDNet model for the identification of tree species based on convolutional neural network was constructed. The stochastic gradient descent (SGDM) method with momentum added was used to optimize the model, and GPU was used to optimize the parallel operation library. The classification accuracy of wood macro- and micro-structure data sets was compared. Result: Compared with the existing GoogLeNet identification method, the accuracy and speed of PWoodIDNet model were increased by 1.49% and 59.69%, respectively. Compared with the existing AlexNet identification method, the accuracy and speed of PWoodIDNet model were increased by 3.76% and 2.63%, respectively. Conclusion: PWoodIDNet model could break through the difficulties of existing identification methods, such as narrow range of wood species, low accuracy and low identification speed, effectively identify wood, and could achieve the best identification effects in less training time. It would be expected to provide a new method and thought for the identification of wood in China.

Objective: Hot-pressed peanut meal (HPM) was used as the research object to prepare HPM adhesive (HPMA) with high bonding strength and good water resistance by composite modified cross-linking,which would expected to provide technical and theoretical basis for its industrial application in the wood field. Method: HPM was modified and crosslinked by sodium dodecyl sulfate (SDS),nano-SiO₂ (nSiO₂) and polyamide polyamine epichlorohydrin (PAE) resin to study the bonding strength of poplar plywood prepared by HPMA in modified cross-linking process. The appearance,viscosity,solid content,pH,thermal stability,protein secondary structure and surface structure of HPMA in the modified cross-linking process were evaluated. Result: The results showed that the dry,warm and boiling water wet bonding strengths of poplar plywood prepared by HPMA increased by 113%,114% and 81%,respectively,and reached the national class I poplar plywood standard. The prepared HPMA was brown,and the viscosity,solid content and pH were 6 448 mPa·s,31.33% and 5.83,respectively. The thermal decomposition temperature of HPMA was as high as 317℃. The secondary structure and groups of proteins changed significantly during the preparation of HPMA,and the microscopic surface structure was tight from coarse. Conclusion: The main reason for the improvement of bonding strength and water resistance was that the secondary and tertiary structure of protein were opened by SDS,exposing the hydrophobic groups,and hyperbranching with nSiO₂ and PAE to form a three-dimensional network structure of insoluble water. It might provide technical and theoretical bases for the industrial application of HPMA.

Rising nitrous oxide (N₂O) concentrations in the atmosphere have exacerbated global warming. Forest soil plays an important role in regulating atmospheric N₂O concentration. Recently,application of phosphate (P) fertilizer was increased for improving forest productivity. However,compared with the well-known effects of nitrogen (N) deposition or N addition on N₂O emission from forest soil,how the P addition affects the N₂O emission from forest soil is still limited and lacks in-depth understanding. This study presents a review of the responses and mechanism of N₂O emissions from forest soils to P addition. Due to the different responses of plant and soil microorganisms (microbial biomass,community composition and microbial activity) to P addition,phosphorus addition can increase,reduce or not change the N₂O emission from forest soil. Overall,phosphorus addition alleviated the P-limitation of plants and soil microbes. The effect of P addition on soil N₂O emissions was governed by the initial status of soil nutrients (N,P). P addition can promote the absorption of inorganic N by plant roots and/or microbial N immobilization,thus reducing the N₂O emission from forest soil,it can also stimulate the activity of nitrification and denitrification bacteria,subsequently promote the N₂O emission from forest soil. Furthermore,phosphorus addition may also regulate soil N₂O emissions by alleviating soil acidification,affecting arbuscular mycorrhizal fungi symbiosis and litter decomposition,which requires further studies. In the future forest management,the addition of phosphorus can be considered as a strategy for reduction of greenhouse gas emission.

Objective: In order to provide a scientific basis for the development and utilization of Ziziphus jujuba var. spinosa germplasm resources,the suitable range for growing Z. jujuba var. spinosa was predicted under the context of climate change. Method: Based on the GIS technology and R language,data of 121 geographical concurrence points and 34 environmental factors were selected for the study. The default parameters of MaxEnt model were adjusted by using ENMeval package in R language,and the geographical distribution of suitable areas for Z. jujuba var. spinosa was predicted by using the optimized MaxEnt model. Person correlation analysis and VIF variance expansion factor were used to select the required factors for modeling,and the jackknife method was used to select the dominant environmental factors of the suitable area. According to the fifth climate model released by IPCC,the changes of future geographical distribution of Z. jujuba var. spinosa under different climate scenarios were discussed. Result: The model optimization showed that the MaxEnt model has the lowest complexity and the best when the feature combination is linear,quadratic and fragmented,and the regulation frequency multiplier is 3.5. The AUC of the working characteristic curve analysis method of the subjects was 0.946,indicating that the prediction model has high reliability and excellent accuracy. The jackknife test showed that the main environmental factors affecting the distribution of Z. jujuba var. Spinose were the annual mean temperature,the mean temperature of wettest quarter,the precipitation of wettest month,the precipitation seasonality,the elevation,and the base saturation of topsoil (0-30 cm). At present,the suitable growing areas for Z. jujuba var. spinosa in China are mainly concentrated in Shaanxi,northern Henan,central and southern Shanxi,Hebei,northern Ningxia and southeastern Inner Mongolia,northeastern Sichuan,western Liaoning and Shandong. Under the different climate scenarios in the future,the suitable areas for Z. jujuba var. spinosa will change in varying degrees. By the 2050s and the 2070s, the suitable areas for Z. jujuba var. spinosa will increase to a certain extent. The suitable areas under RCP 4.5 and RCP 8.5 scenarios respond sensitively,showing an increasing trend,and the increasing trend is weaker under RCP 2.6 scenario than under the other two scenarios. Conclusion: Climate,soil and terrain factors all affect the potential geographical distribution of Z. jujuba var. spinosa,among which climate factors account for the largest weight,which is most likely to cause the migration of geographical distribution of Z. jujuba var. spinosa. The optimized model can accurately simulate and predict the potential geographical distribution area of Z. jujuba var. spinosa. In the future,the climate change of global warming will change the distribution pattern of Z. jujuba var. spinose,the total suitable growing areas will increase,the expansion will be mainly in the middle and high latitudes,and the reduction will be mainly in the low latitudes. Under the three climate change scenarios,the center of suitable areas for Z. jujuba var. spinosa in the 2050s and the 2070s will migrate to high latitudes. The suitable area for Z. jujuba var. spinosa will migrate to the North China Plain and the Northeast Plain as a whole,and the priority should be given to arrange new planting areas in this region,so as to reduce the loss caused by climate change.

Objective: This study aims to investigate the effects of biochar and its aging biochar on the soil main nutrient content and microbial community composition in Chinese fir plantation,and to provide a reasonable selection basis for the use of biochar in Chinese fir plantation in southern China. Method: Chinese fir leaves were used as raw materials to make biochar and the biochar was washed and acidified to simulate the long-term aging in the natural environment of southern China. The red soil in the second generation Cunninghamia lanceolata forest was collected as the experimental soil. Four groups treatments were set up,including no biochar(CK),3% biochar (BC),3% washed aged biochar (WBC),and 3% acidified aged biochar (OBC) added in the soil. After 150 days of indoor cultivation,the main soil nutrients were determined. At the same time,the high-throughput sequencing technology was used to analyze the community composition of soil bacteria and fungi. The correlation between the content of soil main nutrients and the relative abundance of main microorganisms was further analyzed. Result: The addition of biochar can significantly increase the content of total carbon,total nitrogen,dissolved organic carbon,available potassium and nitrate in soil. Aged biochar reduced the content of dissolved organic carbon. OBC also had a significant inhibitory effect on the content of dissolved organic nitrogen(P < 0.05). Venn diagram analysis showed that OBC had the most obvious promotion effect on soil microbial richness. Biochar and aged biochar had a promoting effect on the relative abundance of Proteobacteria,Gemmatimonadetes,Bacteroidetes,Gemmatimonadaceae,Sphingomonadaceae and Rhodospirillaceae. OBC significantly increased the relative abundance of Verrucomicrobia and Planctomycetes. Chloroflexi,Actinobacteria and Firmicutes were significantly negatively correlated with total carbon and total nitrogen,while Proteobacteria and Bacteroidetes were significantly positively correlated with available potassium and nitrate nitrogen. As for fungi,Ascomycota and Basidiomycota were the dominant phyla. WBC increased the relative abundance of Basidiomycota,Mucoromycota and Ganodermataceae. OBC reduced the relative abundance of Chytridiomycota. Ascomycota were significantly positively correlated with ammonium nitrogen and dissolved organic carbon,and the relative abundance of the Mortierellomycota was significantly positively correlated with dissolved organic nitrogen. Conclusion: Biochar can effectively improve the soil main nutrients content of Cunninghamia lanceolata plantation. However,the effect of biochar on soil nutrient improvement is weakened after washing and acidification. Biochar and aged biochar can increase the abundance of microorganisms in general,but there are differences in the regulation of relative abundance of main microbial groups.

Objective: This paper aims to study the alpha-pinene synthase gene and (-)-limonene synthase gene of Pinus armandi and their expression characteristics, and so as to provide theoretical support for revealing the terpene synthase gene in P. armandi to defense against Dendroctonus armandi and its blue-stain fungus Leptographium qinlingensis. Method: The cDNA sequences of alpha-pinene synthase gene and (-)-limonene synthase gene of P. armandi were cloned by PCR and race techniques, and the nucleotide sequence and amino acid sequence of the encoded protein were analyzed by bioinformatics method, and the phylogenetic tree was constructed. The expression differences of alpha-pinene synthase gene and (-)-limonene synthase gene were analyzed by real-time fluorescent quantitative PCR after being treated with MeJA and L. qinlingensis. Result: The full length of the coding region of alpha-pinene synthase gene was 1 887 bp. The protein was composed of 628 amino acids with a molecular weight of 71.59 kDa and the theoretical isoelectric point of 5.86. The full-length coding region of (-)-limonene synthase gene was 1 905 bp. The encoded protein was composed of 634 amino acids with a molecular weight of 73.01 kDa and the theoretical isoelectric point of 5.97. Real-time fluorescence quantitative PCR analysis showed that the expression of alpha-pinene synthase gene and (-)-limonene synthase gene was up-regulated at different time after MeJA treatment. The expression level of alpha-pinene synthase gene reached the peak on the second day, and that of (-)-limonene synthase gene reached the peak on the fourth day. Alpha-pinene synthase and (-)-limonene synthase gene was induced to express by L.qinlingensis, but the expression levels were significantly different at different time points after treatment with L. qinlingensis. The result showed that alpha-pinene synthase gene and (-)-limonene synthase gene were crucial genes in response to L. qinlingensis and MeJA treatments. Conclusion: The alpha-pinene synthase gene and (-)-limonene synthase gene of P. armandi are able to respond to the treatment of L. qinlingensis and MeJA, and play an important regulatory role in the defense of D. armandi and blue-stain fungus. This study provides a theoretical basis for further control of D. armandi.