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Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For Selected: Download Citations EndNote Reference Manager ProCite BibTeX RefWorks Toggle Thumbnails Select VOCs and Odor Emission from Lacquer Veneer Particleboards Qifan Wang,Jun Shen,Bin Zeng,Huiyu Wang,Tianyu Cao,Huajun Dong Scientia Silvae Sinicae    2020, 56 (5): 130-142.   DOI: 10.11707/j.1001-7488.20200515 Abstract （252）   HTML （3）    PDF （2619KB）（72）       Knowledge map    Save Objective: This study was carried out to explore the release characteristics of VOCs and odor from lacquer veneer particleboards,at the same time,analyze the influence of environmental factors on the components of VOCs and odor in the equilibrium state. Two kinds of lacquer Fraxinus mandshurica veneer particleboards were analyzed by gas chromatography-mass spectroscopy/olfactometry in this research. The emission of VOCs and odors from different lacquer veneer particleboards was compared,and the basic data were provided for further odor research. Method: This paper established a single factor experiment matched to the appropriate environmental conditions to analyze the release rule of VOC and odor from nitrocellulose lacquer veneered particleboards and water based acrylic lacquer veneered particleboards under different environmental factors. On the one hand,the characteristic odor compound and their resources from lacquer particleboards were indentified. On the other hand,the effects of environmental factors on the VOCs and the odor release of lacquer particleboards were investigated. Finally,the VOCs and odor release of the two lacquer veneer particleboards were evaluated by the method of "synthetic index-olfactory evaluation method ". Result: Compared with nitrocellulose lacquer veneered particleboard,water based acrylic lacquer veneered particleboard has a lower TVOC concentration,less odor amount and lower total odor intensity. Aromatics and esters exceeded the standard most seriously in both kinds of boards. The main components of odor emission released from nitrocellulose lacquer veneered particleboards were aromatic,esters,and alcohols,whereas,those of water based acrylic lacquer veneered particleboard's were aromatics and alcohols. For different odorous compounds,there was no direct correlation between odor intensity and its concentration,but,for the same odorant compound,its concentration affected the odor intensity somewhat. Furthermore,with the increase of ratio of air exchange rate to loading factor,the TVOC emission concentration and total value of odor intensity from two kinds of lacquer particleboards declined,but it increased with the temperature increase. At the same time,when relative humidity increased,the TVOC emission concentration and total value of odor intensity from nitrocellulose lacquer veneered particleboards increased,but the TVOC emission concentration and total value of odor intensity from water based acrylic lacquer veneered particleboards declined. The proportion of the odor substance concentration in the total VOCs concentration decreased with the increase of temperature and relative humidity. The ratio of air exchange rate to loading factor had a little effect. Conclusion: Gas chromatography-mass spectroscopy/olfactometry could be used as a method to detect the odor from wood-based panels and furniture materials. Compared with nitrocellulose lacquer veneered particleboard,water based acrylic lacquer veneered particleboard might be a more suitable material for interior decoration. The total odor intensity and odor grade of two kinds of painted veneer particleboard might be fitted by Gaussian function. Table and Figures | Reference | Related Articles | Metrics Select Adjuvant's Influence to Droplet Size Based on Forestry Pests' Prevention with Ground and Air Chemical Application Huichun Zhang,Hongping Zhou,Jiaqiang Zheng,Juan Liao,J. Hewitt Andrew Scientia Silvae Sinicae    2020, 56 (5): 118-129.   DOI: 10.11707/j.1001-7488.20200514 Abstract （463）   HTML （43）    PDF （3922KB）（408）       Knowledge map    Save Objective: China has been using the cross-spraying method of air and ground to control forest pests. Stereoscopic spraying chemical has been adopted in the forestry pests control which apply pesticide both on the ground and in the air. Due to greater human awareness of environmental conservation and public health, pests and diseases control requires accurate, efficient, scientific, and reasonable operation according to the actual conditions. A wide variety of choices and decisions must be made by applicators to result in a successful pesticide application. Examples of these choices include proper adjuvant mixture and spray equipment (e.g. nozzle type and orifice size) and application technique (e.g. spraying pressure) selection while also considering environmental influences such as wind speed. Droplet size is one of the most important factors affecting spray application, efficacy, drift and spray performance optimization. Method: A laser diffraction technique in wind tunnel was used to provide complimentary information on droplet size distribution and spectra. Droplet size was determined by application conditions (nozzle type, spraying pressure, operation condition and wind speed), and tank mixing physical properties were affected by the carriers (water or oil) and adjuvants (drift retardant, surfactant and wetting agent). These sprays were atomized using ground nozzles and aerial nozzles placed in a wind tunnel and the droplet spectra measured via a laser diffraction instrument. Result: Experimental results showed that the VMD decreased with the increase of the spray pressure and decrease of nozzle's orifice size. It was also showed by tests that when spraying 41A liquid as drift retardant, VMD produced by nozzles increased compared with water as solution in the wind tunnel, and all the nozzles' RS value increased, the spectrum category changed. When the CHEMWET100 as wetting agent and LI700 as surfactant, VMD produced by import nozzles and domestic nozzle reduced lightly and the spectrum category remained the same. Droplet size sprayed by CP nozzles could be changed both by orifice size and deflector angle. Increasing the deflector angle produced smaller droplets, e.g., 30° produced smaller droplets than those of 0°. Meanwhile, using a downward deflection of 30 degree might have improved relative RS of droplet sizes for CP nozzle. Conclusion: Spray mix composition and adjuvant could have a large effect on droplet size and spray performance criteria. During aerial application, in order to reduce the drift of airborne droplets, appropriate pesticide additives (such as drift retardant 41A) should be added to increase the droplet size and improve their adhesion. During ground application, appropriate pesticide additives (such as surfactant LI700) should be added to reduce the droplet size and enhance the deposition rate in order to ensure the coverage area and canopy penetration. For the leaves of trees with a thick waxy layer, the surface might be difficult to be wetted by the pesticide solution. When spraying pesticides on these targets, the wetting agent CHEMWET should be used to increase the wettability and adhesion of the pesticide solution to the target surface. Table and Figures | Reference | Related Articles | Metrics Select Properties of 3D Printed Bionic Wood Sound Absorption Structure with Different Hole Angles Mingrui Dong,Shifang Jia,Jingyi Liu,Xianxian Lin,Qianwen Xue,Weisheng Sun Scientia Silvae Sinicae    2020, 56 (5): 113-117.   DOI: 10.11707/j.1001-7488.20200513 Abstract （190）   HTML （5）    PDF （1511KB）（87）       Knowledge map    Save Objective: In order to provide theoretical basis for developing of bionic wood sound absorption material, the sound absorption structure of the bionic wood is designed according to the wood structure. Then, the hole angles of the absorption structure are tested. Method: First of all, we modeled the bionic wood sound absorption structure with Rhinoceros 3D software, and prepared this structure by 3D printing technology. The influences of different inclined angles(15°, 30°, 45°, 60°)on the resonant frequency and sound absorption coefficient were investigated by means of impedance tube transfer function. Then, the sound absorption properties of 3D printed perforated plates were compared. Result: 1) This study found that the 3D printed perforated plates had two resonance frequencies, which were at the low frequency and the middle high frequency, respectively. However, the sound absorption structure of 3D printed bionic wood had three resonant frequencies, which were located at low frequency, medium to high frequency and high frequency, and wood perforated plate only had low resonance frequency. 2) The angle of the perforation had effect on the sound absorption performance of the 3D printed perforated plate. At low frequency, the resonance frequency would move to the low frequency direction with the increase of the inclination angle. The peak of the sound absorption coefficient was above 0.8; in the medium to high frequency section, the angle changed with the angle of the complex hole. The resonance frequency and the peak absorption coefficient of 3D printed perforated panel were both changed, but there was no a clear law. However, the peak of sound absorption coefficient was about 0.3, and the sound absorption performance was poor. 3)The inclined angle of the hole had a great influence on the sound absorption property of the 3D printed bionic wood sound absorption structure, the sound absorption law of the low frequency section and the medium to high frequency section was basically the same as that of the 3D print perforated plate. In the high frequency section, the common vibration frequency moved to the low frequency direction with the increase of the hole angle. The peak value was above 0.8, and had a good absorption performance. Conclusion: The 3D printed bionic wood sound absorption structure with different hole angle presented good sound absorption properties at low frequency, medium to high frequency and high frequency, which were not found in the previous studies of perforated sound absorption materials. In addition, at high frequency, the resonance frequency of the 3D printed bionic wood sound absorption structure with different angle is larger, which lays a theoretical foundation for the design of the future full frequency sound absorption structure. This experiment provided a new research field for the new composite materials which can design the sound absorption frequency. It will have a good prospect in some special sound absorption environment. Table and Figures | Reference | Related Articles | Metrics Select A New Species of Zaraea(Leach, 1817)(Hymenoptera, Cimbicidae) from China Harming Padus brachypoda Yuchen Yan,Zejian Li,Guihong Li,Meicai Wei Scientia Silvae Sinicae    2020, 56 (5): 105-112.   DOI: 10.11707/j.1001-7488.20200512 Abstract （406）   HTML （3）    PDF （7074KB）（148）       Knowledge map    Save In this paper, a new species, Zaraea mengmeng Yan, Li & Wei sp. nov. (Hymenoptera:Cimbicidae), collected from the Mt. Tianmu, Zhejiang Province, China, is described. Its larvae feeding on leaves of Padus brachypoda and could defoliate entire leaves of the host tree with high density, which will affect its growth, thus affecting the yield of fruit trees and seriously reducing the economic benefits of trees. The new species develops one generation a year in the Mountains and overwinters in the form of pre-pupa. This new species is very similar to Z. akebiae, but can be distinguished from the latter by the following characters:metanotum and abdominal tergum 1 entirely yellowish white; tibia and tarsus of each leg dark brown; the ventral half of mesepisternum smooth and sparsely punctured. The genomic DNA of the new species was extracted using the DNeasy Tissue Kit (Qiagen, Valencia, CA), 12 sequences of Cytochrome oxidase Ⅰ(COⅠ) (2 sequences of the new species and 10 sequences of other species of Cimbicidae were obtained from the mitochondrial gene, with a length of 850 bp; In addition, we downloaded 23 COⅠ sequences of known Cimbicidae and related genera species used in previous phylogenetic analyses from GenBank database, which constitute the CO Ⅰ sequence data set with the new species sequence (35 samples in total). The genetic distance of Abiinae was analyzed and the results showed that the genetic distance is 0.005 between two samples of the new species. Each of the clade Zaraea, Orientabia and Abia, are recovered as a monophyletic group, with high support for the BI trees (Posterior probability >0.96). We suggest that Zaraea, Orientabia and Abia are three valid genera of Abiinae. Results of molecular analysis of the new species are consistent with those of morphological identification, which supports the establishment of new species. Table and Figures | Reference | Related Articles | Metrics Select Isolation and Identification of Endophytic Bacteria from Xinjiang Wild Apple (Malus sieversii) and Their Antagonism against Three Pathogens of Apple Trees Yongli Li,Yahong Wang,Le Chang,Hairu Yu,Zhou Zhou,Wenxia Zhao,Liangjian Qu Scientia Silvae Sinicae    2020, 56 (5): 97-104.   DOI: 10.11707/j.1001-7488.20200511 Abstract （309）   HTML （9）    PDF （4276KB）（218）       Knowledge map    Save Objective: In this study,endophytic bacteria were isolated and screened from a wild apple (Malus sieversii) in Xinjiang,which is an excellent germplasm resource in China,in order to obtain new bacterial resources for biological control of apple diseases. Method: Endophytic bacteria were isolated from the branches of M. sieversii by the methods of dilution plating and tissue isolation. Seven endophytic bacteria strains,with the strong inhibitory effect on three pathogenic fungi (Botryosphaeria dothidea,Colletotrichum gloeosporioides and Phomopsis mali),were selected by the method of plate confrontation. The 7 strains were identified based on morphological,physiological and biochemical characteristics,as well as 16S rDNA sequence analysis. Their pathogenicity was determined by using in vitro inoculation tests. Result: In this study,a total of 217 strains of endophytic bacteria were isolated and purified,among which seven strains (M-m7,M-m12,M-r12,P-m9,P-m11,L-m12 and P-r21) with strong inhibitory effects on mycelium growth of three pathogenic fungi of B. dothidea,C. gloeosporioides and P. mali were screened out. Their inhibition rates were 77.00%,72.60%,76.60%,60.64%,65.96%,65.81% and 71.79% on B. dothidea; 69.85%,64.95%,68.87%,68.37%,56.12%,53.54% and 65.66% on C. gloeosporioides; 77.63%,79.22%,72.60%,69.37%,70.27%,69.30% and 71.05% on P. mali,respectively. Strains M-m7,M-m12,P-m11 and L-m12 were identified as Bacillus subtilis,strains M-r12 and P-m9 were identified as B. elezensis and strain P-r21 was identified as B. amyloliquefaciens. Inoculation tests showed the 7 strains had no pathogenicity to apple tree itself. Conclusion: Seven strains of endophytic bacteria in M. sieversii can effectively suppress mycelium growth of B. dothidea,C. gloeosporioides and P. mali,and have no pathogenicity to apple tree. Table and Figures | Reference | Related Articles | Metrics Select Stem Volume Models of Phyllostachys edulis in Zhejiang Province Qianyong Shen,Mengping Tang Scientia Silvae Sinicae    2020, 56 (5): 89-96.   DOI: 10.11707/j.1001-7488.20200510 Abstract （296）   HTML （11）    PDF （1375KB）（194）       Knowledge map    Save Objective: Based on the accurate measuring of the stem volume of moso bamboo(Phyllostachys edulis), the research on bamboo stem volume models was conducted to accurately estimate the stem volume and to provide a theoretical basis for the management of bamboo forest. Method: Taking moso bamboo as the research object, based on the measured data of 216 samples of bamboo from Lin'an, Qingyuan, Wuyi, Changshan, Ninghai, Anji, Zhuji, Yuyao, Huangyan and Taishun county of Zhejiang Province, drainage method that could measure the volume of irregular shaped object was used to measure the bamboo stem volume. Firstly, based on the allometric equation and the equation proposed by Terasaki Watari, taking the diameter at breast height(D)and the internode length of bamboo at breast height(L)as the independent variables, one unary model(M1)and four binary models(M2-M5)were selected to establish the three bamboo stem volume models with all the samples data. Secondly, model error structures were analyzed with the likelihood analysis with which whether the log-transformed linear models or nonlinear weighted models were chosen for model fitting. The parameter estimations were obtained by fitting regression of the models using ForStat2.2 software. Finally, the bamboo stem volume model that fit for Zhejiang Province well and had stable parameters and higher prediction accuracy was selected according to analysis towards the results of t test for the parameter estimates and 4 validation statistics, namely the adjusted coefficient of determination(Ra2), the standard error of the estimate(SEE), the mean errors(ME)and the mean systematic errors(MSE). Result: The Akaike's information criterion(AICc)of the 5 basic models were calculated with the likelihood analysis of model error structure. The results showed that the value of ΔAICc was larger than 2, which indicated the multiplicative error and the use of log-transformed model for model fitting. The parameters of the 5 bamboo stem volume log-models established were stable for the absolute t-value was larger than 2. All of the Ra2 were above 0.95, and the SEE and MSE were around 0, respectively, which reflected the well-fitting, and the model M2 fit the best. The statistics of model fitting and prediction across diameter classes were investigated as well. The results illustrated that the fitting and prediction performance across diameter classes of the 5 models was quite preferable, yet better when assuming the medium diameter classes and a bit worse as assuming the class of 4.0-5.9 cm and that of 14.0-15.9 cm. Finally, the prediction log-models with correction did not perform a better fitting effects and prediction precision. Conclusion: Drainage method is a better method for accurate measurement of bamboo stem volume. Likelihood analysis is suitable to analyze the error structure and provide with a reliable justification of choosing the fitting models. The evaluation accuracy of binary models is higher than that of unary model as the variable H and L are introduced. Considering the easier and more accurate measurement of internodes length of bamboo at breast height(L)in practice, and the stem volume model M5 performs better than model M2, the suggested suitable model for predicting the stem volume is M5 that is based on variable D-L, i.e.V=0.191 2D2.114 9e-6.841 1/L. Table and Figures | Reference | Related Articles | Metrics Select Forest Disturbance Monitoring Based on Time Series of Landsat Data Li Zhong,Yunzhi Chen,Xiaoqin Wang Scientia Silvae Sinicae    2020, 56 (5): 80-88.   DOI: 10.11707/j.1001-7488.20200509 Abstract （602）   HTML （29）    PDF （4483KB）（311）       Knowledge map    Save Objective: Considering the character of forest disturbance in China is frequent and complicated, we use the series trajectory analysis method to monitor forest disturbance which can provide references for carbon cycle and carbon accumulation of terrestrial forest ecosystems and climate change research. It is of important significance to the terrestrial carbon cycle and climate change research. Method: We conduct a study in Changting county base on 15 Landsat time-series data from 2000 to 2016 by adopting a time-series trajectory analysis technique(LandTrendr)to identify forest disturbance which apply segment properly and fit linearly a time sequence on the time-series trajectory. The results are verified based on field survey and pixel of interference by using the Google image and global 30 m resolution of GDEM digital elevation products. Result: The total area of forest disturbance is 192.49 km2 and the mean area is 12.83 km2 within the area from 2000 to 2016, of which that in 2001 is the minimum and less than l km2.The most serious disturbance occurred in 2004, 2008 and 2009. The area all over 30 km2 and occupy about 1.3% of forest area in those years. In the three years, the total area represent 50% of the forest disturbed area and the biggest disturbance area is 32.85 km2 in 2004. In 2003, 2006, 2007 and 2010-2011, the disturbance area was slightly larger than 10 km2, but less 0.6% of forest area in this year. It's much less than 10 km2 for remaining years. The area of forest disturbance fluctuates greatly in individual years, but it is decreasing over time. The duration of forest disturbance is mainly about 1 to 3 years and the largest disturbance area occurred in 1 year which up to 82%. Disturbance is mainly concentrated in the east of Changting where is near the non-forest area. It's obvious that disturbance area is declined with the elevation and more than 60% of disturbance occurred at low-middle altitudes. Combined with visual interpretation of Google images, it is shown that the forest disturbance in Changting is mainly caused by forest fires and artificial deforestation, which mainly occurs in low altitude areas near the non-forest areas. Conclusion: The results of field survey and pixel of interference are consistent with the results of monitoring. Disturbance patch can be extract completely and the boundary is accurate and distinct, so is the fine disturbance. Base on pixel scale accuracy verification to monitor forest disturbance, it is showed that the overall accuracy reaches 96.26%, with a Kappa coefficient of 0.92. In all years, the accuracy of users is over 80%., and the accuracy of producers is more than 75% except several years. The results require a high monitoring accuracy, indicating a significant potential of the technique for forest disturbance monitoring. Table and Figures | Reference | Related Articles | Metrics Select Cloning and Salt Tolerance Analysis of Transcription Factor HSFA4 from Betula platyphylla Zhongyuan Liu,Zheng Liu,Ying Xu,Shanshan Liu,Zhilan Tian,Qingjun Xie,Caiqiu Gao Scientia Silvae Sinicae    2020, 56 (5): 69-79.   DOI: 10.11707/j.1001-7488.20200508 Abstract （419）   HTML （20）    PDF （5330KB）（241）       Knowledge map    Save Objective: Heat shock transcription factor (HSF) plays an important regulatory role in plant response to abiotic stress. The aim of this study was to identify the stress resistance function of BpHSFA4 in birch(Betula platyphylla) in order to lay a theoretical foundation for using the gene in tree breeding through genetic engineering. Methods: The BpHSFA4 cDNA sequence was obtained by searching with birch transcriptome libraries. Further, the BpHSFA4 gene was cloned by RT-PCR. And the BpHSFA4 cDNA sequence was analyzed using bioinformatics tools. Quantitative real-time RT-PCR was used to monitor the expression patterns of BpHSFA4 genes in the leaves, stems and roots of birch under different stress treatments. The vector of overexpression pROKⅡ-BpHSFA4 and silencing expression vector of pFGC5941-BpHSFA4 were constructed and transient transformed into birch. The empty pROKⅡ was also transient infected into birch as a control. The MDA content, H2O2, SOD activity, POD activity, electrolyte leakage and diaminobenzidine(DAB), nitrotetrazolium blue chloride (NBT) and Evans blue staining under NaCl stress were measured and compared between transgenic (OE, SE) and control (CK) plants. Results: The results showed that the cDNA length of BpHSFA4 was 1 170 bp. The protein encoded by this BpHSFA4 gene was 389 amino acids. The relative molecular weight of BpHSFA4 protein was 44.15 kDa, with isoelectric point 5.14. The typical HSF domain was found in the BpHSFA4 sequence.The results of qRT-PCR showed that the expressions of BpHSFA4 gene were different under abiotic stresses and hormone treatments compared to the control. Furthermore, the expressions were significantly different at least at one stress point time for each treatment. In addition, the expression patterns of BpHSFA4 gene were more significantly changed under NaCl stress. To determine whether BpHSFA4 displayed a successful overexpression(OE) or a suppressed expression (SE), the transcript levels of BpHSFA4 in the three types of transformed birch plants were measured by qRT-PCR. The results showed that the expression of BpHSFA4 was significantly higher in OE plants and clearly lower in SE plants, especially 12 h after transformation, indicating that these transient expression plants were suitable for further study. Under NaCl stress, The NBT and DAB staining and H2O2 content also showed that overexpression of BpHSFA4 markedly reduced ${\rm{O}}_2^{\bar \cdot }$ and H2O2 accumulation, while suppressed expression of BpHSFA4 led to elevated accumulation of ${\rm{O}}_2^{\bar \cdot }$ and H2O2. The SOD and POD activities of transgenic birch plants showed that OE had the highest SOD and POD activities, and that SE plants had the lowest SOD and POD activities. The Evans blue staining and MDA content and electrolyte leakage showed that cell death greatly decreased in the OE plants, but greatly increased in the SE plants. Conclusion: BpHSFA4 gene can respond to abiotic stresses and hormone treatments, and stronger under salt stress, it indicates that the gene may be involved in the response to salt stress in birch trees. All results indicated that overexpression of BpHSFA4 improved the salt stress tolerance by increasing the ability to scavenge reactive oxygen species (ROS), the activities of SOD and POD to reduce the accumulation of H2O2 and ${\rm{O}}_2^{\bar \cdot }$, thereby reducing cell damage or cell death and enhancing birch resistance. BpHSFA4 was proved to be a candidate gene responding to stresses. Table and Figures | Reference | Related Articles | Metrics Select Characterization and Phylogenetic Analysis of Ostrya multinervis Chloroplast Genome Ming Jiang,Shisheng Ke,Junfeng Wang Scientia Silvae Sinicae    2020, 56 (5): 60-68.   DOI: 10.11707/j.1001-7488.20200507 Abstract （293）   HTML （10）    PDF （3561KB）（232）       Knowledge map    Save Objective: Ostrya multinervis is a species endemic to China, and it is listed as a rare and endangered wild plant, and a species with extremely small population in Zhejiang Province. The wild O. multinervis trees are found to be very rare in Zhejiang Province with very few young-aged plants and a declining population. During the evolution process, the chloroplast genomes are relatively conserved and thus provide useful information for genetic relationship analysis and phylogenetic studies. In the present study, based on the assembly of chloroplast genome, sequence characteristics were determined to confirm its structure and gene organization. By phylogenetic analysis, relationships and taxonomic ranks with its relative were identified. Methods: Genomic DNA of O. multinervis was extracted by using CTAB method, and a library was constructed for high-throughput sequencing with HiSeq X Ten with the paired-end strategy. The chloroplast genome was assembled by using NovoPlasty, and PCR was applied to isolate the border sequences following sequencing verification. SSR loci were detected by MISA and a phylogenetic tree was generated using PhyML 3.0. Results: A total of 19 869 412 clean reads were obtained by getting rid of both adaptors and low quality sequences. The result indicated that the complete O. multinervis chloroplast genome was 159 583 bp in length containing a typical quadripartite structure, and the lengths of large single copy, small single copy, and inverted repeat were 88 514 bp, 18 953 bp, and 26 058 bp, respectively. The O. multinervis chloroplast genome contains 131 genes, with 87 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. Among them, ycf1 and ycf15 were pseudogenes, and their sequences were shorter than normal ones. A total of 58 SSR loci were predicted from O. multinervis plastome, and 53 of which were mononucleotide repeats. Multiple sequence comparison showed the highest similarity between O. multinervis and O. rehderiana (99.1%) and the lowest was between O. multinervis and O. japonica (98.7%). The best fit model for constructing a phylogenetic tree was GTR+G+I, and the Akaike information criterion and Bayesian information criterion were 556 643.629 64 and 556 954.642 07, respectively. The phylogenetic analysis indicated that 12 plants could be divided into two groups, and Alnus japonica and A. rubra from the tribe Betuleae were grouped into one clade, while 10 plants from tribe Coryleae were grouped into another clade. O. multinervis and the other three Ostrya species clustered in the same clade with 100% of bootstrap support. Conclusion: Based on the high-throughput sequencing, the chloroplast genome of O. multinervis was assembled, and its structure and gene organizations were confirmed. Higher similarities in chloroplast genome sequences were found between O. multinervis and other three Ostrya species, and they shared the same clade. The assembly, sequence comparison and phylogenetic analysis provide a basis for genetic structure and population diversity studies in the future. Table and Figures | Reference | Related Articles | Metrics Select Influence of Open Vessel Proportion on the Types of Embolism Vulnerability Curves Han Zhao,Jin Huang,Youjing Zhang,Yanjun Lu,Zaimin Jiang,Jing Cai Scientia Silvae Sinicae    2020, 56 (5): 50-59.   DOI: 10.11707/j.1001-7488.20200506 Abstract （281）   HTML （6）    PDF （3026KB）（116）       Knowledge map    Save Objective: Plant embolism vulnerability is a hot issue in hydraulics studies of woody plants, and is generally assessed by establishing vulnerability curve (VC). Centrifuge method is one of the main method being applied to establish the VC. Previous studies have generally believed that when the Cavitron centrifuge method was used to establish the VC of a long-vesselled tree species, the vessels inside the centrifuged branch was cut open, and the presence of a large number of open vessels causing the embolism artifact, resulting in extremely vulnerable "r-shaped" curve, so significantly overestimated the cavitation vulnerability of plants. This study was intended to test whether the type of VC is affected by the proportion of open vessels at the inter-specific level, and to lay a foundation for the reliability of centrifuge method in assessing the plant embolism vulnerability, therefore, the plant's cavitation resistance can be more accurately evaluated, which provides a reliable basis for the selection of drought-resistant tree species in ecological construction. Methods: Nine tree species with different vessel lengths were selected. According to the Cavitron centrifuge rotor diameter (27.4 cm), nine tree species were divided into three categories:long-vesselled species (average vessel length > 15 cm, Robinia pseudoacacia, Morus alba and Lagerstroemia indica), medium-vesselled species (average vessel length 10-15 cm, Ligustrum lucidum, Amygdalus persica, Hippophae rhamnoides) and short-vesselled species (average vessel length < 10 cm, Acer truncatum, Corylus heterophylla, Populus alba 'I-101'×(P. alba×P. glandulosa '84K'). The VCs were established by Cavitron centrifuge. Maximum and mean lengths of vessels were measured by air injection technique. Relationships between open vessels fractions and characteristics of the VCs were analyzed. Results: The VCs of long-vesselled species and short-vesselled species of A. truncatum and C. heterophylla could be well fitted by single Weibull function, while the VCs of medium-vesselled species and short-vesselled species of I-101×84K could be well fitted by double Weibull function. The VCs of long-vesselled R. pseudoacacia and M. alba were similar, showing "r-shaped", while that of L. indica was "s-shaped"; the VCs of medium-vesselled H. rhamnoides and L. lucidum, and short-vesselled I-101×84K were double Weibull shape consist of two "s-shaped" curves, while the VC of medium-vesselled A. persica was closer to "s-shaped"; the VCs of short-vesselled A. truncatum and C. heterophylla were both "s-shaped". The mean vessel lengths (Lv) of long-vesselled species were close to 20 cm, the proportion of vessels with both ends opened (F27.4) was about 20%, the proportion of vessels opened from one end to the center of centrifuge rotor (F13.7) was about 60%; the Lv of medium-vesselled species was close to the radius of centrifuge rotor (13.7 cm), F27.4 was about 10%, and F13.7 was about 40%; the Lv of short-vesselled species was below 5 cm, F27.4 was less than 0.1%, and the maximum value of F13.7 was 2.68%. The embolism vulnerability indices P12 and P50(xylem water potentials correspond to hydraulic loss of 12% and 50%, respectively) of nine species were positively correlated with the proportion of open vessels (F27.4 and F13.7), but P88(xylem water potential corresponds to hydraulic loss of 88%) was not significantly correlated with the proportion of open vessels. Conclusion: At the inter-specific level, this study verified that the proportion of open vessels significantly affected the types of embolism vulnerability curves established by Cavitron centrifuge. When the proportion of open vessels was very few, the VCs were "s-shaped", but with the increase of the proportion of open vessels, the "r-shaped" and "intermediate-shaped" curve may be formed. This conclusion further supports the hypothesis of open vessel artifacts, and provides a theoretical basis for the selection of tree species when measuring the embolism vulnerability by Cavitron centrifuge. Table and Figures | Reference | Related Articles | Metrics Select Dynamics of Seed Rain, Soil Seed Bank and Seedling Regeneration of Castanopsis hystrix Zong Zhao,Yong Liu,Zuwei Tian,Hongyan Jia,Ruirui Zhao,Ning An Scientia Silvae Sinicae    2020, 56 (5): 37-49.   DOI: 10.11707/j.1001-7488.20200505 Abstract （345）   HTML （7）    PDF （3471KB）（185）       Knowledge map    Save Objective: Castanopsis hystrix is a rare broadleaved tree species under the second grade national protection in China, and it is difficult to regenerate in nature. Our study aims to examine whether population regeneraion is limited by seedling recruitment. We investigated dynamics of seed rain, soil seed bank and seedling regeneration of C. hystrix. Methods: The line transect method was used to collect the seed rain and fallen leaves of C. hystrix in 2017 and 2018. Seed rain density, quality, total of seed rain and weight of fallen leaves in different seed dispersal stages were analyzed. At the same time, small plots were also set under the seed trees for collecting samples in litter layer, 0-5 cm humus layer and 5-10 cm soil layer. The soil seed bank density and the number of full seeds were calculated then, and the germination capacity and the weight of thousand seeds were measured in laboratory. In May 2018, small plots were set around each of sampling seed trees to investigate the seedlings regeneration. Results: 1) Seed rain of C. hystrix lasted from the middle of September to the late of December, and its concentrated scatter period was from October to November. In 2017, it was a big year for producing seeds of C. hystrix, and the seed rain density was (480.97±11.61) seeds The seed quality was good, the number of full seeds was (433.86 ±12.65) seeds·m-2, accounting for 90.20%±1.09% of the total seed rain. In 2018, it was a small year for seed production, both seed production and full seeds proportion were lower than those in 2017. The seed rain density was (126.37±12.04) seeds·m-2, and the full seeds accounted for 36.04%±0.95% of the total seed rain. 2) The soil seed bank in April 2018 was mainly from the seed rain in 2017, and the average density of soil seed bank was (360.09±10.43) seeds·m-2, of which full seeds accounted for 59.74%±8.56%. By indoor germination test in 2018, the average germination rate of full seeds was 28.53%±7.50% in seed bank. There were about (61.38±18.57) seeds·m-2 having germination potential before natural regeneration. However, when the seeds were buried into the forest soil till April in 2019, the germination rate decreased to 2.85%±0.86%, and only about (8.59±1.90) seeds·m-2 had germination capacity in seed bank. Approximate 63.79%±3.55% of seeds in the bank were mainly distributed in litter layer. 3) The average renewal frequency of seedlings of C. hystrix was 16%, and only 11 of the 78 regenerated seedlings were survived. Conclusion: The dynamics of seed rain diffusion is consistent with that of fallen leaves of C. hystrix. The vertical spatial distribution of soil seed bank is significantly different, and the most of the seeds fall into litter layer. The germination rate and survival rate of seedlings are low, it is still difficult for seedling recruitment even if after a big year of C. hystrix. Thus, low seed germination rate and litter barrier are the main influencing factors leading to the poor regeneration of C. hystrix. Table and Figures | Reference | Related Articles | Metrics Select Effects of Two Growth Retardants on the Growth of Chestnut Branches and the Accumulation of Carbon and Nitrogen Metabolites in Leaves Yichi Zhang,Sujuan Guo Scientia Silvae Sinicae    2020, 56 (5): 29-36.   DOI: 10.11707/j.1001-7488.20200504 Abstract （361）   HTML （9）    PDF （1305KB）（390）       Knowledge map    Save Objective: In this study, the effects of paclobutrazol (PP333) and chlormequat (CCC) on the growth of chestnut young branches and leaves, and carbon-nitrogen metabolism of leaves were investigated, which aims to provide a scientific basis for comprehensive understanding of the effects of plant growth retardants on the growth of chestnut saplings and their application. Methods: The 6-year-old Chinese chestnut variety Castanea mollissima 'Yanshanzaofeng' was selected as the test material. Two kinds of retardants, paclobutrazol and chlormequat, were sprayed on the leaves during the rapid growth period of branches. The retardant concentrations were set as 100, 200 and 300 mg·L-1, with water served as the control (CK). After treatment, the growth index of mother branch, fruit branch, vegetative branch, single leaf area, leaf length-width ratio, leaf water content, relative chlorophyll, carbon and nitrogen metabolite content were regularly measured, and those collected data were used to explore the effect and application feasibility of the two kinds of retardants. Results: The main results were as follows:1) Paclobutrazol and chlormequat significantly inhibited the longitudinal growth of mother branch, fruit branch and vegetative branch of young chestnut trees, and promoted the basal diameter, and there were significant (P < 0.05) differences of all treatments compared with the control. For fruit branches, the effect of spraying 200 mg·L-1 chlormequat was the most significant on length growth, and the growth was about 81% less than the control. The growth of base diameter of fruit branch was significantly increased by spraying 100 mg·L-1 chlormequat, and the growth was about 74% higher than the control. 2) Paclobutrazol and chlormequat significantly reduced the single leaf area and increase the ratio of leaf length to width, leaf water content and relative chlorophyll content. Among treatments, spraying 200 mg·L-1 chlormequat reduced the single leaf area by 11% compared with the control, and increased the relative chlorophyll content by 10.28% compared with the control. Spraying 300 mg·L-1 paclobutrazol significantly increased the content of leaf water, with 28% higher than the control. 3) Paclobutrazol and chlormequat were able to significantly promote the accumulation of carbon and nitrogen metabolites of young chestnut leaves. Compared with the control, spraying 300 mg·L-1 paclobutrazol or 100-200 mg·L-1 chlormequat significantly increased the content of soluble sugar, total nitrogen and the ratio of carbon to nitrogen. Conclusion: Based on the comprehensive analysis of the effects of two kinds of retardants on branch growth and leaf physiological indexes, it is found that spraying 100-200 mg·L-1 chlormequat during the rapid growth period of young trees can significantly promote the diameter of mother branch and fruit branch, and inhibit their elongation growth, and also effectively promote the accumulation of carbon and nitrogen metabolites in leaves. Table and Figures | Reference | Related Articles | Metrics Select Characteristics of Forest Ecosystem Carbon Stocks at Different Vegetation Restoration Stages in Hilly Area of Central Hunan Province, China Zhenpeng Wang,Jinlei Chen,Shangyi Li,Shiji Zhang,Xi Fang Scientia Silvae Sinicae    2020, 56 (5): 19-28.   DOI: 10.11707/j.1001-7488.20200503 Abstract （348）   HTML （17）    PDF （1456KB）（302）       Knowledge map    Save Objective: The aims of this study were to investigate the change trends of carbon storage and its distribution pattern(vegetation, litter and soil layer) within forest ecosystems at different restoration stages in hilly area of central Hunan Province of China, in order to provide a scientific basis for explaining the influence mechanism of vegetation restoration on carbon sink function of forest ecosystem, and implementing forest ecosystem carbon reservoir management measures in stages. Methods: By using the space-for-time substitution method, we selected four different types of ecosystems, comprising of Loropetalum chinense+Vaccinium bracteatum+Rhododendron simsii scrub-grass-land (LVR), L. chinense+Cunninghamia lanceolata+Quercus fabri shrubbery (LCQ), Pinus massoniana+Lithocarpus glaber+L.chinense coniferous-broad leaved mixed forest (PLL), and L. glaber+Cleyera japonica+Cyclobalanopsis glauca evergreen broad-leaved forest (LAG) to represent the successional sequence in the secondary forests in Changsha County, Hunan Province, China. Permanent plots were established in each ecosystems.Biomass was estimated by using the total harvesting method to establish relative growth equations of some dominant tree species and citing allometric equations of biomass of some dominant tree species. Soil samples (0-40 cm) were collected and divided into four layers (0-10, 10-20, 20-30, and 30-40 cm). Carbon contents in plant, litter, and soil samples were determinated, and carbon storage of vegetation, litter, and soil were estimated. Results: Carbon contents of different components at different vegetation layers varied with vegetation restoration. In the same restoration stage, carbon contents of different components at different vegetation layers ranked in the order of the arbor layer > the shrub layer > the herb layer. Carbon contents of litter were highest in PLL, followed by LAG and LCQ as the lowest. Soil organic carbon contents increased with the vegetation restoration.From LVR to LAG, carbon storage of vegetation, litter, 0-40 cm soil and ecosystem increased by 70.80, 1.17, 67.05 and 139.02 tC·hm-2, respectively. The growth rate of carbon reserves in vegetation layer and ecosystem between different stage showed the characteristics of first fast and then slow. However the growth rate of carbon reserves in soil showed fast-slow-fast. Carbon stock within ecosystem showed a consistant spatial distribution pattern:0-40 cm soil layer > vegetation layer > litter layer in different restoration stages. With vegetation restoration, the contribution rate of carbon stock in vegetation layer to the ecosystem carbon stock increased, while that of soil carbon stock was in the decline, and that of litter carbon stock did not change. Carbon storages of ecosystem, vegetation, and soil were significantly positively correlated with species diversity index (except for vegetation), biomass in vegetaion, and soil organic carbon content. Conclusion: With vegetation restoration, plant diversity, vegetation biomass, soil organic carbon content, carbon storages of ecosystem and its each components (vegetation, litter and soil) increased. However the growth rates of carbon reserves in vegetation, soil and ecosystem showed different among different restoration stages. Therefore, it is an important way to improve the carbon reserve of subtropical forest ecosystem to promote forest vegetation restoration and improve tree species diversity, vegetation biomass, and soil organic carbon content in order to improve carbon reserves of the vegetation and soil by reasonable management measures in the early and middle of restoration stages, and to protect the above-ground vegetation and ensure the continuous increase of soil organic carbon content in the late stage of vegetation restoration. Table and Figures | Reference | Related Articles | Metrics Select Effects of Nitrogen and Water Addition on Leaf N:P Stoichiometry of the Two Dominant Species in Artemisia ordosica Community Jie Fu,Weiwei She,Yuxuan Bai,Yuqing Zhang,Yangui Qiao,Shugao Qin Scientia Silvae Sinicae    2020, 56 (5): 12-18.   DOI: 10.11707/j.1001-7488.20200502 Abstract （334）   HTML （22）    PDF （2305KB）（490）       Knowledge map    Save Objective: A three-year (2015-2017) nitrogen and water addition control experiment was conducted in the southwestern margin of the Mu Us sandy land to investigate the effects and action pathways of increased nitrogen and moisture on the two dominant plant species (Artemisia ordosica and Leymus secalinus).This study was aimed to provide theoretical basis and case support for predicting nutrient cycling in desert ecosystems and nutrient limiting conditions for plant growth under future global environmental changes. Methods: For three successive years (2015-2017), a field control experiments with 2 factors and 9 interactive treatments were conducted in Ningxia Yanchi, Southwestern edge of Mu Us sandy land. Three nitrogen addition levels were N0(0 kg·hm-2a-1), N10(10 kg·hm-2a-1), and N60(60 kg·hm-2a-1). Three water addition levels were W0(natural precipitation), W20(20% increase over natural precipitation), and W40(40% increase over natural precipitation). We performed two-way ANOVAs to examine the responses of soil moisture, soil inorganic nitrogen and soil available phosphorus, soil Ca2+ content, and the leaf N:P of A. ordosica and L. secalinus to nitrogen and water addition. Then we used structural equation modeling to test their relationships. Results: Nitrogen addition significantly increased soil inorganic nitrogen and the leaf N:P of A. ordosica and L. secalinus, while no significant effects on soil available phosphorus and soil Ca2+ content were detected. Water addition decreased the leaf N:P of L. secalinus and soil Ca2+ content, but had no significant effect on soil inorganic nitrogen, soil available phosphorus, and the leaf N:P of A. ordosica. Conclusion: Nitrogen addition relieved the N limitation, but exacerbated P limitation. Water addition reduced the leaf N:P by changing soil (0-20 cm) Ca2+ content, therefore P limitation has been alleviated to some extents. Table and Figures | Reference | Related Articles | Metrics Select Biomass Estimation Coefficient and Its Impacting Factors for Eucalyptus Plantation in China Wankuan Zhu,Yuxing Xu,Zhichao Wang,Apeng Du Scientia Silvae Sinicae    2020, 56 (5): 1-11.   DOI: 10.11707/j.1001-7488.20200501 Abstract （609）   HTML （35）    PDF （1533KB）（612）       Knowledge map    Save Objective: The relationship between the three biomass estimation coefficients and the stand structure, climatic factors, and topographic factors was analyzed, and the main influencing factors of biomass estimation coefficients were determined to provide a scientific basis for accurately estimating the biomass of Eucalyptus plantations at regional scale. Method: By collecting and collating historical data from published literature on biomass measurements of Eucalyptus plantations, we analyzed and explored the relationship between three common biomass estimation coefficients (biomass conversion and expansion factor BCEF, biomass expansion factor BEF, and root/shoot ratio R) and stand structure (stand age, mean DBH, mean tree height, stand density, and standing volume), climatic factors (annual average temperature and annual average precipitation), and topographic factor (elevation). Result: Means of BCEF, BEF, and R were 0.658 Mg·m-3 (n=119, SD=0.150), 1.251 (n=176, SD=0.167), and 0.190 (n=144, SD=0.102), respectively. The corresponding range values were 0.46-0.76 Mg·m-3, 1.05-1.35, and 0.04-0.36, respectively. BCEF value displayed a decrease followed by an increase with the increase of mean DBH. BCEF value gradually decreased with the increase of mean tree height (r2=0.366), stand density (r2=0.430), and standing volume (r2=0.405). BEF value decreased and became stable with the increase of stand age(r2=0.765), mean tree height(r2=0.734), and standing volume(r2=0.578), decreased first and then increased with the increase of mean DBH(r2=0.644). R value decreased gradually and then became stable with the increase of stand age(r2=0.665), mean tree height(r2=0.338), stand density(r2=0.275), and standing volume(r2=0.403).BCEF value showed a decrease first followed by an increase with the increases of temperature (r2=0.193) and precipitation (r2=0.200). Values of BEF and R did not show a significant functional relationship with changes in temperature and precipitation. Three biomass estimation coefficients showed a trend of increase with elevation, and the equation fitting accuracies were 0.455, 0.501, and 0.314. Conclusion: The goodness of fit between stand density and BCEF was relatively high, and so did the stand age and the BEF and R. Stand density and age were the main factors affecting the estimation coefficient of biomass. The influence of topographic factors on the three biomass estimation coefficients was next only to the stand density and the age. The climatic factor only had some effects on the BCEF. Therefore, the difference in biomass estimation coefficients caused by stand structure and topographic factors should be considered when estimating the biomass of Eucalyptus plantations at regional scale. Table and Figures | Reference | Related Articles | Metrics Select Simulation on Cluster Layout Wooden Furniture Production Line Based on FlexSim Wei Wang,Yunting Wang,Wenlong Song Scientia Silvae Sinicae    2020, 56 (4): 135-142.   DOI: 10.11707/j.1001-7488.20200415 Abstract （294）   HTML （15）    PDF （1053KB）（362）       Knowledge map    Save Objective: In order to solve wooden furniture production line of machine-group layout under multi-product and small lot-size production is prone to create bottlenecks, then resulting in low productivity, we study how to determine the bottleneck and improve the production efficiency in this paper, and through the actual production line to verify the validity and feasibility of the scheduling scheme, the consistence of actual production results and the simulation results are also compared. This paper establishes a model of cluster layout production line with FlexSim. This model trends to save the actual running cost of wooden furniture production line, and it also can be used as a reference for improving the efficiency of other wooden furniture production lines. Method: Taking a cluster layout wooden furniture production line for an example, by setting parameters of source, processor, storage area, transport and other entities according to production hours, transportation hours, production batch and order plan of each order, the model with FlexSim is simulated. Through analyzing simulation results, namely the average process rate and release rate of each process, we can identify the bottleneck process in production line, set time buffer for production system and schedule the orders according SPT (shortest processing time) rule. Result: We can get the state parameters of each working procedure in production line by FlexSim simulation, in which the average process rate of blanking process, milling process, sanding process, assembling process, painting process and testing process is 45.30%, 62.70%, 74.13%, 52.80%, 54.53% and 54.20%, and the release rate of these processes is 42.00%, 57.50%, 72.40%, 22.70%, 30.90% and 29.90%, respectively. Therefore, the average process rate of sanding process is the highest, at 74.13%, and the release rate of sanding process is the highest too, at 72.40%, so the sanding process is the bottleneck of the wooden furniture production line. According to time buffer calculation model, the bottleneck time buffer of each order is 24 min, 31.5 min, 30 min and 36 min, the delivery time buffer of each order is 30 min, 54 min, 54 min and 72 min. Through simulation by FlexSim, we can get that the average process rate of SPT scheme is 90.28%, which increases 16.15% compared with the original plan. By comparing the results of the actual operation and the simulation results, the average processing rate and the average idle rate error of each process are within the range of ±5%. Conclusion: This paper investigates a cluster layout wooden furniture production line model with FlexSim7.lnk, and it can effectively identify the bottleneck of the production line and predict the production results. The bottleneck process might be eliminated by setting the production line time buffer, and a fine schedule according to SPT rule could greatly improve production efficiency of the wooden furniture production line. Table and Figures | Reference | Related Articles | Metrics Select Mechanical Properties of Full-Scale Glulam Beam Made of Thermally Treated Lamellas Kong Yue,Xulei Song,Xuekai Jiao,Qiang Chen,Yongming Song,Weiqing Liu,Weidong Lu Scientia Silvae Sinicae    2020, 56 (4): 128-134.   DOI: 10.11707/j.1001-7488.20200414 Abstract （255）   HTML （8）    PDF （2138KB）（104）       Knowledge map    Save Objective: The mechanical properties of full-scale glued laminated timber(glulam) beams made of thermal treated laminas were performed. The effects of thermal modification and humidity in the surrounding environment on wood moisture content, longitudinal shear strength and tensile strength were determined. The study can provide a reference for thermal treatment technology in the structural applications. Method: The high-grade Larix gmelinii was used in the tests. A total of 12 full-scale glulam beams were fabricated with modified laminas using industrial thermal modification technology. The effects of humidity in the surrounding environment and industrial thermal treatment on bending properties were determined, including bending strength, modulus of elasticity(MOE), failure mode, the relationships between load and deformation and the strain profile of full-scale glulam beams. All beams were tested using the four-point bending method according to BS EN 408 standard. Result: The results showed that, thermal modification improved MOE significantly in high humidity with a slight reduction in bending strength. In 90% relative humidity, bending strength of thermally treated glulam beams decreased by 29.79% than that of the untreated. MOE of thermally treated glulam beams increased by 23.71% than that of the untreated. MOE of the untreated glulam beams under the two humidity conditions was 23.27% difference, and the thermally treated glulam beams under the two humidity conditions was only 7.55% difference. The curves of bending load with displacement and strain profile curves of the glulam beams in different relative humidity showed that, the untreated glulam beams exhibited a more nonlinearity than the thermally treated glulam beams, especially at a high moisture in the surrounding environment. The relationships between moisture in the surrounding environment and mechanical properties were negatively correlated. Compared with the untreated control at 60% relative humidity, bending strength and modulus of elasticity of glulam beams at 90% relative humidity were 43.98 MPa and 12.191 GPa, and low ered by 17.07% and 23.27%, respectively. The effects of humidity in the surrounding environment on equilibrium moisture content of wood specimens were significant, and equilibrium moisture content of wood specimens can be deduced obviously by industrial thermal treatment. Thermal treatment decreased equilibrium moisture content from 10.74% to 4.76% and from 20.62% to 11.18% at 60% and 90% relative humidity, respectively. Conclusion: The untreated glulam beams at 60% and 90% relative humidity both failed in tension mode, while the series of the thermally treated glulam beams all failed in combined flexure and shear mode. Longitudinal tensile strength and shear strength of wood specimens both decreased after thermally treated, and led to the decrease of bending strength of the glulam beams. Industrial thermal treatment technology could improve modulus of elasticity of glulam beams significantly in a high relative humidity with a reduction in bending strength, so thermally treated wood materials could be used in construction after checked in bending strength. Table and Figures | Reference | Related Articles | Metrics Select Diapause of Hyphantria cunea (Lepidoptera: Arctiidae) Induced by Photoperiod and Temperature Shaobo Wang,Zhou Zhou,Yimeng Chen,Yuzhu Wang,Yong Zhang,Liangjian Qu Scientia Silvae Sinicae    2020, 56 (4): 121-127.   DOI: 10.11707/j.1001-7488.20200413 Abstract （458）   HTML （4）    PDF （1129KB）（137）       Knowledge map    Save Objective: This paper aims to investigate effects of photoperiod and temperature on the diapause of Hyphantria cunea, to clarify main factors of inducing the diapause, and to unveil the sensitive larval instars to photoperiod inducing the diapause. Method: In this experiment, four temperatures (21, 23, 25 and 27℃) and 7 photoperiods (L8:D16, L10:D14, L12:D12, L13:D11, L14:D10, L15:D9 and L16:D8) were set. The diapause incidence of these 28 treatments were analyzed and compared to show the effects of photoperiod and temperature and critical photoperiod on diapause of H. cunea. Under the condition of 23℃, the larvae were alternately treated with long photoperiod (L16:D8) and/or short photoperiod (L10:D14) at different developmental stages. The diapause incidence under 32 different treatments were statistically analyzed and compared to determine the sensitive period of larval instars for diapause induced by the photoperiod. Result: At four different temperatures (21, 23, 25 and 27℃), the day time less than 13 h caused the diapause of H. cunea, while when the day time reached 16 h tended the individual continued to develop without diapause. The diapause is controlled by photoperiod and temperature at the same time when the day length was in the range of 13 to 16 h, and the diapause incidence decreased with the increase of temperature or photoperiod. The critical photoperiod was 14 h 58 min:9 h 02 min (L:D), 14 h 45 min:9 h 15 min (L:D), 14 h 35 min:9 h 25 min (L:D) and 14 h 24 min:9 h 36 min (L:D) at 21, 23, 25 and 27℃, respectively. Also, the response of the larvae to short photoperiod inducing diapause is cumulated, and the 3rd, 4th and 5th instar were the most sensitive instars to short photoperiod inducing diapause of H. cunea. Conclusion: The results indicate that the H. cunea is a typical short-photoperiod diapause (long photoperiod development) insect. The photoperiod plays a crucial role in the process of diapause induction, and temperature is the cofactor of diapause induction. Low temperature and short photoperiod are favorable for the diapause, and the critical photoperiod shortens with the increase of temperature. It is found that 3-5 instar of H. cunea larvae are the most sensitive developmental stage to diapause induction by short photoperiod. Table and Figures | Reference | Related Articles | Metrics Select Diversity of Endophytic Fungi in Heartwood and Sapwood of Dalbergia odorifera Changlin Liu,Guoying Zhou,Bai Xiao,Jun Liu Scientia Silvae Sinicae    2020, 56 (4): 109-120.   DOI: 10.11707/j.1001-7488.20200412 Abstract （275）   HTML （10）    PDF （7775KB）（140）       Knowledge map    Save Objective: This paper aims to study the diversity of the fungus community structure in heartwood and sapwood of Dalbergia odorifera, and their relationship with the internal environmental factors, in order to provide a basis for the evaluation of endophytic fungi and resource utilization in the trunk of D. odorifera, and further to provide a theoretical basis for artificially promoting the formation of heartwood of D. odorifera. Method: High-throughput sequencing technology was used to study the community structure and diversity of endophytic fungi in the heartwood and sapwood, and the relationship with the physical and chemical properties of heartwood and sapwood was analyzed by means of variance analysis and redundancy analysis. Result: A total of 2 193 336 sequences were obtained with high-throughput sequencing. The total number of bases was 761 438 850 bp, and the effective sequence had an average length of 385 bp. There were 3 621 OTUs, belonging to 26 classes, 67 orders, 116 families, 167 genera and 186 species. At the class level, the dominant flora of endophytic fungi of heartwood was:Agaricomycetes, Sordariomycetes and Eurotiomycetes; the dominant flora of endophytic fungi of sapwood was:Sordariomycetes, Dothideomycetes, Agaricomycetes, Geoglossomycetes and Tremellomycetes. At the genus level, the dominant fungi of endophytic fungi in heartwood were:Phaeoacremonium, Fusarium, Sporothrix, Cladophialophora and Gongronella; the dominant endophytic fungi insapwood were:Fusarium, Lasiodiplodia, Cladosporium, Candida, Debaryomyces and Trichoderma. At the species level, the dominant flora of endophytic fungi of heartwood was:Sporothrix lignivora, Gongronella butleri and Fusarium oxysporum; the dominant flora of endophytic fungi of sapwood was:Lasiodiplodia theobromae, yeast Debaryomyces udenii and Fusarium pseudensiforme. The results of redundancy analysis showed that pH, ash and potassium were negatively correlated with the community structure of endophytic fungi, and hot water extract, magnesium and calcium were positively correlated with most fungal communities, and negatively correlated with a small number of fungal communities. Water content, hot water extract, mineral element calcium and magnesium were positively correlated with the diversity index, such as chaol, shannon and simpson, while pH, ash and potassium were negatively correlated with them. Conclusion: Endophytic fungal population is rich in heartwood and sapwood of D. odorifera.The richness and diversity of endophytic fungi community in the heartwood arelarger than that in the sapwood. The structural differences in endophytic fungal populations in heartwood and sapwood are mainly affected by wood environmental factors, such as pH, ash and mineral element potassium. The diversity of endophytic fungi populations in heartwood and sapwood is mainly affected by environmental factors in wood, such as pH, water content, mineral elements calcium and potassium. Table and Figures | Reference | Related Articles | Metrics Select Effects of Regional Landscape Pattern on the Epidemic of Poplar Rust Disease: A Case Study of Populus alba in Yanqing, Beijing Jingwei He,Yiying Zhang,Chengming Tian,Dianguang Xiong,Yingmei Liang Scientia Silvae Sinicae    2020, 56 (4): 99-108.   DOI: 10.11707/j.1001-7488.20200411 Abstract （212）   HTML （4）    PDF （3977KB）（79）       Knowledge map    Save Objective: This study aims to explore the relationship between the landscape pattern and the epidemiology of poplar rust disease, and explain the incidence of poplar rust disease in Yanqing district of Beijing in terms of the landscape, in order to provide essential information for the control of the disease. Method: A total of 78 sites were set in Yanqing, Beijing to investigate the disease. According to the disease classification standards, the incidence of poplar rust disease was recorded, and the disease index was calculated. Based on the remote sensing image classification map of the research area, the sample site is set as the center and a buffer zone with a radius of 250, 500, 750 and 1 000 m was set up. Fragstats software was used to calculate the landscape metrics of landscape level and class level in each scale buffer zone.R software was used to implement statistical analysis, correlation analysis of landscape metrics under different scales, and stepwise regression analysis of disease index and landscape metrics, and Canoco, the ecological statistical analysis of ware, was used for RDA analysis of class level. Result: The result showed that the disease occurred frequently in the study area, with the disease index between 5.6 and 94.1. The severity of the disease was significantly affected by the landscape pattern, habitat environment and management status. At the landscape level, the landscape pattern in different buffer zones had different responses to the severity of poplar rust disease, and the factors with significant influence on the disease were also different. At the class level, cropland patches and grassland patches had significant impacts on the occurrence of poplar rust disease, which was mainly reflected in the common metrics such as patch density(PD), and intersperse and juxtaposition index IJI. Conclusion: In the landscape structure, the corridor of road and the foundation of grassland and cultivated land provide convenient conditions for the spread of disease, which can promote the occurrence of poplar rust disease. In this study, the landscape pattern of 500 m buffer is the optimal scale of disease management. Under this scale, the landscape metrics establish the most significant correlation with the disease index. Combined with the pathological characteristics of poplar rust disease, this study considers that the occurrence of the disease can be explained by the area-shape, landscape aggregation and diversity. The complexity of the shape of the patches inside the landscape and the level of diversity of the landscape will affect the occurrence of disease, and it will greatly promote the prevalence of disease with dispersed patches in the landscape, refined landscape structure as well as the uniform distribution between patches. Table and Figures | Reference | Related Articles | Metrics Select Analysis and Evaluation on Oxidation Characteristics of Hazelnut Oil Based on Electron Spin Resonance and Raman Spectroscopy Nana Cui,Guixi Wang,Ruhua Li,Qinghua Ma,Tiantian Zhao,Lisong Liang Scientia Silvae Sinicae    2020, 56 (4): 89-98.   DOI: 10.11707/j.1001-7488.20200410 Abstract （286）   HTML （4）    PDF （3394KB）（190）       Knowledge map    Save Objective: This study investigated the quality change, free radical formation and fatty acid composition of hazelnut oil during oxidation process, and there by revealed the oxidative characteristics which aimed to provide important theoretical basis and technical supports for the quality detection and shelf life prediction for hazelnut oil. Method: A main cultivar of hybrid hazelnut (Corylus heterophylla×C.avellana 'Dawei') was used as the trial material. Hazelnut oil was obtained by the screw pressing method. The accelerated oxidation experiment of hazelnut oil was carried out in an oven at 60℃. The changed regulation of peroxide value (POV), p-anisidine value (AV), total oxidation value (TV), conjugated diene value, relative contents of fatty acids, total carotenoid content, relative content of free radicals and internal structure of the molecules were determined in hazelnut oil during the oxidative period, and the correlations of these indicators were analyzed. Result: During the oxidative process of hazelnut oil, the initial values of POV, AV, TV and conjugated diene were 6.22 meq·kg-1, 0.31, 12.75 and 0.12, and then the values increased significantly to 370.47 meq·kg-1, 25.91, 766.85 and 3.48 at the end of the oxidation process for 40 days, respectively. The relative contents of saturated fatty acids and unsaturated fatty acids changed from 5.96% and 93.69% to 6.35% and 93.20%, respectively. The relative content of free radicals increased rapidly from 8.41 to 28.09. Total carotenoid content of hazelnut oil was not detected after 30 days of oxidation. The change of characteristic peak intensity of 1 158 cm-1 and 1 524 cm-1 in Raman spectra was consistent with total carotenoid content. Raman relative intensities of I972 cm-1/I1 441 cm-1, I1 268 cm-1/I1 441 cm-1, I1 158 cm-1/I1 441 cm-1 and I1 524 cm-1/I1 441 cm-1 were positively correlated with the unsaturated degree. Conclusion: The oxidation of hazelnut oil is roughly divided into three stages, namely initial slowly oxidative stage, rapidly intermediate oxidative stage and later deeply oxidative stage. The oxidative degree of hazelnut oil can be well evaluated according to comprehensive four oxidation indexes (namely, POV, AV, TV and conjugated diene value). Carotenoids are the main contribution factors to the color of hazelnut oil, and closely related to the oxidative degree of hazelnut oil.The relative content of free radicals, characteristic peak intensity of Raman spectra and total carotenoid content have a significant correlation with conventional oxidation indexes, which proves that electron spin resonance (ESR) and Raman spectroscopy can be used to evaluate the oxidative degree in hazelnut oil. ESR and Raman spectroscopy have great potential as supplement or replacement for evaluation methods of traditional lipid oxidation, providing a new method for rapidly nondestructive test of lipid quality. Table and Figures | Reference | Related Articles | Metrics Select Comparative Analysis of Chloroplast Genome Characteristics between Paeonia jishanensis and Other Five Species of Paeonia Xiaojun Zhou,Kai Zhang,Zhengfeng Peng,Shanshan Sun,Huiyuan Ya,Yanzhao Zhang,Yanwei Cheng Scientia Silvae Sinicae    2020, 56 (4): 82-88.   DOI: 10.11707/j.1001-7488.20200409 Abstract （300）   HTML （7）    PDF （1921KB）（284）       Knowledge map    Save Objective: China's wild peony has been regarded as precious germplasm resources at home and abroad. Wild Paeonia jishanensis is considered as one of the most important ancestral species of cultivated tree peonies. The analysis of chloroplast genome (cp DNA) characteristics of Paeonia, including P. jishanensis, has important theoretical and practical values for elucidating the phylogeny of Paeonia and developing improved varieties. Method: Chloroplast data of P. jishanensis were obtained by high-throughput sequencing. The cp DNA data of P. ostii, P. ludlowii, P. delavayi, P. veitchii and P. obovata were downloaded from NCBI database. Comparative analysis of the six peony cp DNA was performed using Geneious 8.0 and EMBOSS 6.4.0. Result: The cp DNA sequence of P. jishanensis was 152 628 bp with 112 genes, 25 988 codons encoding 78 proteins. There are 19 genes (including 4 rRNA, 7 tRNA, 8 protein coding genes) repeat in the IR (Inverse Repeat) region. A total of 143 SSR loci were searched, the mononucleotide repeat are the most common (116, accounting for 81.12%), and there was no hexanucleotide repeat motif. Although the chloroplast genome of Paeonia is conservative, there are still some changes in the boundary of IR and LSC(large single-copy) between different species. The rpl2 gene of P. ostii extends 718 bp to the LSC region, while that of other species are completely located in the IR region. Conclusion: Paeonia cp DNA genome size and gene content are highly conserved. The cp DNA of P. obovata and P. delavayi was the largest (152 698 bp), and that of P. ostii was the smallest (152 153 bp). The codons of cp DNA protein coding genes and the base composition of SSR loci in P. jishanensis prefer to use A/T. Among 143 SSR loci, 134 loci were A/T loci. The distribution of cp DNA SSRs in P. jishanensis has heterogeneity, 14 SSR loci were located in IR region, 103 in LSC region and 26 in SSC region. Analysis showed that boundary change of LSC/IRb was the main reason for the expansion or contraction of IR region in Paeonia. The results provide a basis for the studies of phylogeny and origin of cultivation, and for the development of molecular markers and the breeding of elite cultivars of Paeonia plants. Table and Figures | Reference | Related Articles | Metrics Select Codon Usage Bias and Its Influencing Factors in Pinus massoniana Transcriptome Peihuang Zhu,Yu Chen,Lingzhi Zhu,Rong Li,Kongshu Ji Scientia Silvae Sinicae    2020, 56 (4): 74-81.   DOI: 10.11707/j.1001-7488.20200408 Abstract （228）   HTML （13）    PDF （2310KB）（355）       Knowledge map    Save Objective: Heterologous expression is an important means of plant protein function verification and molecular breeding. Codons are important factors for efficient expression of heterologous genes. An analysis of codon bias of gene coding region of Pinus massoniana transcriptome was conducted in order to provide a theoretical basis for molecular breeding of P. massoniana. Method: Analysis of codon parameters and bias in P. massoniana transcriptome by using CodonW, EMBOSS and other codon analysis software. According to the neutral mapping, ENc-GC3s correlation analysis and bias analysis speculates the main reasons for codon bias. The optimal codons of P. massoniana were screened by comparing the relative synonymous codon usage(RSCU) of high and low expression gene samples, and the codon bias differences between P. massoniana and Arabidopsis thaliana, Nicotiana tabacum, Populus tremula, Escherichia coli and Saccharomyces cerevisiae were analyzed by codon usage frequency ratio. Result: The average GC content of P. massoniana transcriptome coding sequence(CDS) codon was 44.95%, and GC content in the third position of codon was 38.95%, especially preferred A/T. Statistical analysis of high and low expression gene samples indicated that the difference of the relative synonymous codon usage (RSCU) in the transcriptome of P. massoniana was small, the 27 codons such as TTA, CAA, TGT and GGT can be used as the optimal codons for P. massoniana. Neutral mapping, ENc-GC3s correlation analysis and bias analysis showed that the formation of P. massoniana codon preference may be mainly affected by mutation, and secondly affected by multiple factors such as natural selection. Codon usage frequency analysis showed that the codon bias in P. massoniana was less different from N. tabacum, A. thaliana and P. tremula. The difference with E. coli was the largest, and the difference with S. cerevisiae was smaller than E. coli. Conclusion: Among the 27 optimal codons screened, 25 codons have the third one as A/T. P. massoniana prefers the third codon as A/T. The formation of P. massoniana codon preference may be mainly affected by mutation, and secondly affected by multiple factors such as natural selection. N. tabacum is the preferred plant organisms for heterologous expression of P. massoniana and S. cerevisiae may be superior to E. coli in the microorganism. Table and Figures | Reference | Related Articles | Metrics Select Effect of Enzymatic Hydrolysis Lignin Mass Concentration on the Structure of Lignin Nano Particles and Drug-Loading Behavior Yu Zhou,Yanming Han,Gaiyu Li,Fuxiang Chu Scientia Silvae Sinicae    2020, 56 (3): 109-116.   DOI: 10.11707/j.1001-7488.20200312 Abstract （301）   HTML （13）    PDF （5155KB）（238）       Knowledge map    Save Objective: The effects of enzymatic hydrolysis lignin(EHL)mass concentration in tetrahydrofuran(THF)on the structure of lignin hollow nanoparticles(LHNPs)and the effects of the structure of doxorubicin hydrochloride(DOX)loaded LHNPs(DOX@LHNPs)on the drug controlled release behavior were investigated in this study, which might provide bases for selecting entrapment utilization of LHNPs in different fields. Method: LHNPs were prepared with dissolving different quality of EHL in THF and afterward dropping deionized water to the solution. EHL could be self-assembled into nanoparticles and loaded DOX- iniside LHNPs forming drug-loaded nanoparticles, by adding a certain quality of DOX to the mixed solution. The microstructure and particle size of the material were characterized by transmission electron microscope(TEM), scanning electron microscope(SEM), laser particle size analyzer(DLS)and surface area and a pore volume analyzer. Ultraviolet-visible spectrophotometer(UV-vis), X-ray diffractometer(XRD) and infrared spectrometer(FTIR)were performed to quantify the encapsulation and controlled release of DOX by LHNPs. Result: The value obtained by DLS showed that an increase of the pre-dropping lignin mass concentration from 0.3 to 3 mg·mL-1 led to the nanoparticles size decreased from 552.6 to 266.8 nm, whereas the PDI values were basically stable. Additionally, the distribution for size of nanoparticles was uniform, which could be stored in water for more than 10 days. Moreover, the size of shells, surface area and pore volume were also decreased with the increase of pre-dropping lignin mass concentration. Hollow spherical structure of lignin nanoparticles with a hole on the surface was observed by TEM and SEM. The test result of UV-vis, XRD and FTIR showed that DOX could be loaded by LHNPs. The behaviors of DOX release were different in two pH systems. For the same test object, the drug released slightly rapidly in acidic(pH=5.5)condition comparing with in neutral(pH=7.4)condition. The larger specific surface area and porosity could improve the encapsulation ability of hollow nanoparticles for DOX, and the thicker shell particles had more stable controlled release result for DOX. Conclusion: The EHL could be microphase-separated in tetrahydrofuran and self-assembled into a dimensionally stable nano-scale surface with hollow spherical particles of a single pore. By controlling the initial mass concentration of lignin, it might be possible to obtain hollow particles of different diameters and shell wall thicknesses. For DOX@LHNPs, the larger the area and porosity is, the greater the drug loading. However, the hollow drug-loaded nanoparticles with more regular structure and thicker shell walls were beneficial to the stable release of DOX. Table and Figures | Reference | Related Articles | Metrics Select Drilling Vibration Identification Technique of Two Pest Based on Lightweight Neural Networks Yu Sun,Xiaoqian Tuo,Qi Jiang,Haiyan Zhang,Zhibo Chen,Shixiang Zong,Youqing Luo Scientia Silvae Sinicae    2020, 56 (3): 100-108.   DOI: 10.11707/j.1001-7488.20200311 Abstract （379）   HTML （9）    PDF （4235KB）（505）       Knowledge map    Save Objective: In order to early warn stealthy wood boring pest, lightweight neural networks were designed and implemented in the present study, and the acoustics recognition technique was used to automatically identify larvae boring vibrations of Semanotus bifasciatus (Coleoptera:Cerambycidae) and Eucryptorrhynchus brandti (Coleoptera:Curculionidae). Method: The SP-1L piezoelectric vibration probe of the AED-2010L sound pick-up was embeded into the woods sections with larvae of S.bifasciatus and E.brandti, the boring vibrations were recorded by the sound recorder. The sounds of S.bifasciatus, E.brandti and no insect were preprocessed by endpoint detection algorithm and time warping algorithm to calculate the log mel-spectrograms. The log mel-spectrograms were then fed into the convolutional neural networks (CNNs). The boring vibrations were short impulses, thus their size was far smaller than that of images. In this paper the InsectFrames of a light-weight CNN were designed in order to prevent over-fitting of the mode. The insectFrames consisted of four convolutional layers using 3×3 kernels. Global average pooling was located before the connected layer, which can reduce parameters of network.The present study proposed four different CNNs which named InsectFrames_1-4 based on different feature interlayer dimensions and dimensionality reduction method. Result: The vibration identification method for identifying the two insect boring vibrations based on neural networks was able to efficently monitor the occurrence of forest boring insects early, and accurately identify the pest species.The sounds of S.bifasciatus, E.brandti and no insect were recognized using InsectFrames_1-4.The average accuracy on the test set reached more than 90%, and the average recognition time of CPU was about 0.1-1.3 s. Among them, model InsectFrame-2 was the best and its accuracy was 95.83%, and the accuracy was 34.2% higher compared to the Gaussian mixture model which is widely used for insect sound recognition.The accuracy increased by 6.94% compared to the heavy-weight ResNet18 model designed for image classification, and the time efficiency increased by more than 170 times. Conclusion: The proposed method applies neural network and sound identification technique to automatic monitoring of larvae boring vibrations, which can improve the early warning of forestry boring insects, and has the advantages of high efficiency, simplicity and low cost. Table and Figures | Reference | Related Articles | Metrics Select Spatiotemporal Niche of Competition and Coexistence of Three Tomicus spp. Infesting Pinus yunnanensis during the Transferring Stage from Shoots to Trunk Chengxu Wu,Fu Liu,Xiangbo Kong,Sufang Zhang,Zhen Zhang Scientia Silvae Sinicae    2020, 56 (3): 90-99.   DOI: 10.11707/j.1001-7488.20200310 Abstract （373）   HTML （3）    PDF （1881KB）（268）       Knowledge map    Save Objective: This study aims to elucidate the distribution regulation and relationship of competition and coexistence of three Tomicus minor, T. yunnanensis and T. brevipilosus (Coleoptera, Scolytidae) infesting Pinus yunnanensis shoots and trunks during the transferring stage from shoot to trunk, and provide theoretical support for population monitoring and integrated control of the three Tomicus species in the future. Method: Based on niche theory, the relationship between niche and population distribution of three Tomicus spp. feeding on P.yunnanensis during the transferring stage from shoot to trunk was studied by using sampling method with pruner in Xiangyun County, Yunnan province. Result: The peak time in both sexes of T. minor was later than that of T. yunnanensis in the crowns of P. yunnanensis, respectively, while there was no significant peak of T. brevipilosus. T. minor was distributed in the base of crowns, while T. yunnanensis and T. brevipilosus were distributed in the upper parts. In the early stage of invasion, T. yunnanensis was distributed in the whole stems of P. yunnanensis, and gradually distributed to the middle-upper part of stem as T. minor infested from the base to upper of stem. The population density of T. minor was significantly different in different heights of Yunnan pine trees, while that of T. yunnanensis was significantly different during the later stage of trunk-boring. There was significant difference in the temporal- and spatial- niche among the three Tomicus species, as well as between the sexes. The temporal-niche breadth in T. minor was more than that T. yunnanensi. On the contrary, the spatial-niche in T. minor was lower than that T. yunnanensi. Conclusion: T. minor and T. yunnanensis co-existed and homologously competed with each other through the allocation and compensation of spatial and temporal resources. The temporal resources in T. brevipilosus were separated from the former two beetle species. Table and Figures | Reference | Related Articles | Metrics Select Isolation and Identification of the Pathogens Causing Witches' Broom Disease of Five Bamboo Species of Non-Phyllostachys Xiansheng Geng,Jinping Shu,Jianli Sheng,Wei Zhang,Han Peng Scientia Silvae Sinicae    2020, 56 (3): 82-89.   DOI: 10.11707/j.1001-7488.20200309 Abstract （400）   HTML （17）    PDF （2280KB）（227）       Knowledge map    Save Objective: In this study, we isolated and characterized the causal agents of witches' broom disease on 5 bamboo species of non-Phyllostachys, and analyzed the morphological features and culture characteristics of the pathogens, which would provide a scientific basis for identifying of the pathogen, controlling the witches' broom disease of bamboo, and determining the phylogenetic relationship of Clavicepitaceae. Method: The pathogens of witches' broom disease were isolated from the infected tissues of five bamboo species of non-Phyllostachys in Hangzhou of Zheijiang and Xishuangbanna, Yunnan through the conventional tissue isolation approach. The species identification was conducted based on morphological methods combined with molecular biology. The morphology and conidia size of the pathogens were determined by microscope, and the phylogenetic relationships of Clavicipitaceae were investigated based on the ITS rDNA and LSU rDNA sequences. Result: The morphological structure of the pathogens isolated from Semiarundinaria sinica, Bashania fargesii and Pseudosasa amabilis var. tenuis were similar to Aciculosporium take. The conidia of pathogenic fungus formed a pale yellow colony with uneven fold, slightly glossy surface and irregular edge on PDA plate. The conidia of pathogenic fungus was needle shape, (22.4-52.0) μm×(2.2-6.0) μm in size. The mycelia of pathogenic fungi isolated from the infected tissues of Dendrocalamopsis stenoaurita and Dendrocalamus strictus formed round colony with smooth surface and regular edge on PDA plate. The pathogen produced short rod-like conidia after 72 days of culture, and the size of the conidia was (5.4-10.5) μm×(1.2-2.8) μm. The sequence analysis and phylogenetic analysis based on ITS rDNA and LSU rDNA showed that the pathogenic fungus isolated from S. sinica, B. fargesii and P. amabilis var. tenuis were clustered with A. take with 99% bootstrap support, and the pathogenic fungus isolated from D. stenoaurita and D. strictus were clustered with Heteroepichloë bambusae with 100% bootstrap support. Conclusion: The causal agent of witches' broom disease of S. sinica, B. fargesii and P. amabilis var. tenuis is A.take, which is closely related to the genus Claviceps.The causal agent of witches' broom disease of D. stenoaurita and D. strictus. is H.bambusae, which is closely related to the genus Balansia, but distantly related to the genus Epichlo. Table and Figures | Reference | Related Articles | Metrics Select Spatio-Temporal Patterns of Evolution Urban Greenspace during the Last Three Decades in Four Typical Cities of China Jiali Jin,Cheng Wang,Baoquan Jia Scientia Silvae Sinicae    2020, 56 (3): 61-72.   DOI: 10.11707/j.1001-7488.20200307 Abstract （376）   HTML （15）    PDF （7695KB）（463）       Knowledge map    Save Objective: Changsha, Dalian, Nanchang and Shenzhen were selected to detect the spatio-temporal patterns of greenspace changes and main impact factors.This study aims to provide the new spatial data for the improvement of urban greenspace theories and models, and for the optimization of greenspace network. Method: Based on the time-series Landsat composites imagess, NDVI-thresholding technique was applied to reclassify greenspace into four categories and landscape indices were used to measure the characteristics of greenspace patterns. Temporal dynamics of greenspace was assessed using the Mann-Kendall trend test. Normalized distance index (NDI) was calculated to measure the urban-to-rural gradients. Dynamic time warping (DTW) was applied to detect the differences of long-term trends trajectories of landscape indices in four cities. Finally, maximum information-based non-parametric exploration method (MINE) was used to detect the pairwise relationships between the changes in greenspace patterns and main impact factors. Result: From 1985 to 2011, the percentage of dense vegetation in Changsha, Dalian, and Shenzhen had an average increase of 0.26% and the mean patch size of dense vegetation increased 0.11 hm2. The percentage of medium-dense vegetation in these three cities had an average decrease of 0.40%, while the mean patch size in Nanchang and Shenzhen increased 0.15, 0.04 hm2 respectively, however, Changsha and Dalian decreased 0.01, 0.08 hm2 respectively. The percentage and mean patch size of sparse vegetation in Changsha and Nanchang showed an increase trend. The percentage increased by 0.12% and 0.23%, the mean patch size increased by 0.04 and 0.01 hm2, respectively. To the contrary, the percentage of sparse vegetation in Dalian and Shenzhen decreased 0.22% and 0.63% while the mean patch size decreased 0.04 and 0.06 hm2.The urban-to-rural gradients of dense vegetation in Changsha and Nanchang had a ∩-shaped trajectory. Sparse vegetation in Changsha and Shenzhen had a monotonic decreasing trajectory, while Dalian, and Nanchang had a ∪-shaped trajectory. The changes in greenspace patterns had strong non-linear relationships with income, gross domestic product per person, proportion of urban population and proportion of city area. Conclusion: From 1985 to 2011, the dense vegetation in Changsha, Dalian and Shenzhen increased and the patches became more connected, contrasting to medium-dense vegetations. In the four selected cities, sparse vegetation increased in inland cities and the patterns became less fragmented, contrasting to the coastal cities. There are three trajectories of urban-to-rural gradients of greenspace, the first one is parabola-shaped trajectory ("∩or∪"), second is constant trajectory ("-"), third is monotonic increasing or decreasing trajectory. The greenspaces tended to have large changes in the city centers and suburb areas. Table and Figures | Reference | Related Articles | Metrics Select A Deep Learning Method for Forest Fine Classification Based on High Resolution Remote Sensing Images: Two-Branch FCN-8s Ying Guo,Zengyuan Li,Erxue Chen,Xu Zhang,Lei Zhao,Yan Chen,Yahui Wang Scientia Silvae Sinicae    2020, 56 (3): 48-60.   DOI: 10.11707/j.1001-7488.20200306 Abstract （492）   HTML （22）    PDF （8345KB）（340）       Knowledge map    Save Objective: The study was conducted to perform the two-branch improvement on fully convolutional network models to explore a new method for the deep learning classification of remote sensing images of forest types with a high spatial resolution, with an aim to provide technical support for the improvement of the accuracy of remote sensing investigation of forest resources. Method: The two-branch FCN-8s contained two FCN-8s sub-models. One sub-model was constructed by fine-tuning based on RGB three-band features and the other sub-model was constructed based on five-band features. The sampling results of these two sub-models at 8, 16, and 32 magnifications were fused and classified to obtain the category of each pixel. Taking Wangyedian forest farm as the research area, the normalized difference vegetation index (NDVI) was extracted based on GF-2 satellite remote sensing images. In addition, the data set based on R+G+B three-band features, R+G+B + NIR four-band features and R+G+B + NIR + NDVI five-band features was constructed to evaluate the effectiveness of the two-branch FCN-8s optimization method quantitatively. Result: 1) The overall classification accuracy of the two-branch FCN-8s method is 85.89% and the Kappa coefficient is 0.84. Compared with the traditional FCN-8s, the dual-branch FCN-8s method can improve the classification accuracy of most forest types, especially for Chinese pine, Korean pine and white birch, and the improvement effects are significant. 2) Compared with the SVM model based on traditional features, the overall classification accuracy of the dual-branch FCN-8s method increaseds from 75% to 85.89%. The accuracy is improved by over 10%. The classification effects of each category are also improved. 3) With the fine-tuning strategy and NDVI features, the model can effectively improve the classification effects of Chinese pine, aspen and white birch. Conclusion: The deep learning precision classification method for forest types with dual-branch FCN-8s high-resolution remote sensing images can effectively improve the subdivision degree and the classification accuracy of forest types. Table and Figures | Reference | Related Articles | Metrics Select Light Saturation Point Determination and Biomass Remote Sensing Estimation of Pinus kesiya var. langbianensis Forest Based on Spatial Regression Models Lü Zhou,Guanglong Ou,Junfeng Wang,Hui Xu Scientia Silvae Sinicae    2020, 56 (3): 38-47.   DOI: 10.11707/j.1001-7488.20200305 Abstract （388）   HTML （18）    PDF （2837KB）（255）       Knowledge map    Save Objective: This paper aims to determinate the light saturation point of biomass estimation using remote sensing data of Simao pine(Pinus kesiya var. langbianensis)forest, and construct the spatial global model and the local remote sensing information model, then inverse the biomass of Simao pine forest. The results will provide a reference for estimating biomass of Simao pine using remote sensing data. Method: This study calculated the light saturation point of Simao pine forest biomass using the quadratic term function and power function model based on Landsat8 OLI images, and the forest resource inventory data in 2016 of Pu'er city, Yunnan Province, were used to construct the remote sensing information model with the ordinary least square(OLS), spatial lag model(SLM), spatial error model(SEM)and geographically weighed regression(GWR), and then the aboveground biomass of Simao pine forest was estimated. Result: 1) The light saturation point of aboveground biomass estimated by Landsat 8 OLI remote sensing in Simao pine forest of Pu'er city was 106.3 t·hm-2. 2) The highest coefficient of determination(R2=0.373)and the lowest Akaike information index(AIC=4 577.8)of GWR model indicated that it has the better fitting performance than OLS, SLM and SEM model. 3) The results of the independent sample test showed that the estimation accuracy of GWR model was higher than those of OLS, SLM and SEM model, especially at the high value stage (above 100 t·hm-2) and the low value stage (below 50 t·hm-2) based on the Jackknife method test. 4) The aboveground biomass by inversion using GWR model was 66.496 t·hm-2, and its estimation error with the measured data was 23.511%, which was less than the estimation values of OLS, SLM and SEM model. Conclusion: GWR model is superior to OLS model and other spatial global regression models in estimating biomass of Simao pine forest in Pu'er city by remote sensing. Moreover, GWR model can solve the problems of high-value under estimation and low-value over estimation to a certain extent, and reduce the influences of the light saturation point on the accuracy of remote sensing estimation. Table and Figures | Reference | Related Articles | Metrics page Page 1 of 6 Total 153 records First page Prev page Next page Last page