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Advances in Remote Sensing Retrieval of Forest Aboveground Biomass REN Xiaoqi, HOU Peng, CHEN Yan Forest and Grassland Resources Research    2023, 0 (6): 146-158.   DOI: 10.13466/j.cnki.lczyyj.2023.06.018 Abstract （518）   HTML （20）    PDF （1148KB）（4673）       Knowledge map    Save Forest aboveground biomass is one of the key indicators to reflect the status of forest ecosystem,which is of great significance to global climate change and China's carbon peak and carbon neutrality.With the rapid development and increasing maturity of remote sensing technology,it has become the main technical means for retrieving above-ground forest biomass in large areas.In this paper,the research progress of remote sensing inversion of forest aboveground biomass was discussed from two aspects through systematic review of relevant literatures at home and abroad.From the perspective of data source,it can be summarized as inversion methods of optical remote sensing data,synthetic aperture radar data and LiDARdata,and the effective information,advantages and limitations provided by each data source are expounded and analyzed.From the perspective of inversion model,it can be summarized as multiple regression model,machine learning algorithm and mechanism model,and the characteristics of different models are discussed and analyzed combined with practical application cases.Finally,this paper summarized the existing problems in the inversion of forest above-ground biomass by remote sensing,and prospected the direction and hotspots of forest above-ground biomass inversion by remote sensing in the future. Table and Figures | Reference | Related Articles | Metrics

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Key Data Results and Trend Analysis of the Sixth National Survey on Desertification and Sandification ZAN Guosheng, WANG Cuiping, LI Feng, LIU Zheng, SUN Tao FOREST RESOURCES WANAGEMENT    2023, 0 (1): 1-7.   DOI: 10.13466/j.cnki.lyzygl.2023.01.001 Abstract （4829）   HTML （377）    PDF （1091KB）（3121）       Knowledge map    Save The Sixth National Survey on Desertification and Sandification was based on the results of the Third National Land Survey,using 2019 as the benchmark year.The results showed a comprehensive status of desertification and sandification in China.This paper presented a brief overview of this survey,the status and dynamic changes of desertification and sandification in China,conducted a comprehensive analysis of the current situation,and proposed some suggestions for combating desertification and sandification.The survey results showed that,until 2019,the desertification land area in China was 257.371 3 million hm2 and the sandification land area was 168.782 3 million hm2.Compared with 2014,the desertification area of China decreased by 3.788 0 million hm2 with an average annual decrease of 757.6 thousand hm2.The sandification area of China decreased by 3.335 2 million hm2 with an average annual net reduction of 667 thousand hm2. Table and Figures | Reference | Related Articles | Metrics

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Grassland Vegetation Coverage Retrieval Based on Sentinel-2 Multi-Spectral Remote Sensing Data: A Case Study of Inner Mongolia Autonomous Region TIAN Haijing, WANG Lin, HAN Liliang, FAN Yunbao, YANG Jilin FOREST RESOURCES WANAGEMENT    2022, 0 (4): 134-140.   DOI: 10.13466/j.cnki.lyzygl.2022.04.017 Abstract （613）   HTML （20）    PDF （4757KB）（2654）       Knowledge map    Save High-precision grassland vegetation coverage remote sensing estimation model is important for quantitative assessment of grassland quality and fine management of grassland.Based on Sentinel-2 multi-spectral remote sensing data and measured sample plots in Inner Mongolia autonomous Region,grassland vegetation coverage was modeled and inverted.The results showed that:1)There was a significant correlation between the 23 vegetation indexes and the measured vegetation coverage (P<0.001),and the highest correlation coefficient was NDVI with a correlation coefficient of 0.834;2)The underestimation of sinusoidal function was more obvious in the high value part (coverage>75%),while the overestimation of linear function was more obvious in the low value part (coverage<25%),by using these two kinds of functions to simulate vegetation coverage,the results were better;3)The grassland types were divided into 6 groups to modeling vegetation coverage respectively.Finally,correlation coefficient between simulated and measured vegetation coverage for the 1 894 sample plots was R2=0.722,P<0.01,RMSE=12%;4)The vegetation coverage of different grassland types in Inner Mongolia from high to low was 78.91% for mountain meadow,73.7% for temperate meadow steppe,53.89% for lowland meadow,52.57% for temperate steppe,32.76% for temperate desert steppe,25.52% for temperate grassland desert and 19.29% for temperate desert. Table and Figures | Reference | Related Articles | Metrics

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Species Diversity and Its Associated Factors of Castanopsis orthacantha Community in Central Yunnan PENG Zexi, LUO Hang, LI Xiaoying, XU Yanhong, YIN Wuyuan, ZHU Hongqin, CHEN Yuqiang, CHEN Xiaoqin FOREST RESOURCES WANAGEMENT    2023, 0 (2): 138-146.   DOI: 10.13466/j.cnki.lyzygl.2023.02.019 Abstract （356）   HTML （9）    PDF （1023KB）（2638）       Knowledge map    Save In order to accurately grasp the species diversity level of Castanopsis orthacantha community and its relationship with related factors in central Yunnan,based on the investigation of typical plots,the Margalef richness index,Pielou evenness index,Shannon-Weiner diversity index and species diversity comprehensive index were used to measure the species diversity level of Castanopsis orthacantha community,and the grey correlation analysis method was used to explore the relationship between species diversity level and site factors,stand factors and forest disturbance intensity.The results showed that:1) The species composition of Castanopsis orthacantha community was rich,involving 75 families,141 genera and 202 species,and the species composition of shrub layer was the most complex.The tree species composition of the arbor layer had the characteristics of typical subtropical evergreen broad-leaved forest.And there were significant differences in species composition and important values in different regions.2) The richness index,diversity index and evenness index of shrub layer (including regeneration layer) were the highest,and the species diversity of Castanopsis orthacantha community was at a medium level.The species diversity of different survey areas in the study area was different.The contribution rate of herb layer and shrub layer (including regeneration layer) to the comprehensive index of community species diversity was the highest.3) There was a strong correlation between species diversity and six factors in three levels of site factors,stand factors and forest disturbance intensity.The order of correlation degree was altitude>forest disturbance intensity>average DBH>aspect>plant density>slope.Through research,the aim is to provide a basis for the restoration and conservation measures of Castanopsis orthacantha community in central Yunnan. Table and Figures | Reference | Related Articles | Metrics

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Habitat Characteristics and Effects on Growth of Arundinaria faberi in Different Slope Positions of Subalpine Meadow YAN Keyu, CHEN Pingping, LI Jianxing, ZHANG Limei, LIU Hui, CHEN Zhengfa FOREST RESOURCES WANAGEMENT    2023, 0 (2): 70-78.   DOI: 10.13466/j.cnki.lyzygl.2023.02.010 Abstract （348）   HTML （7）    PDF （2297KB）（2474）       Knowledge map    Save As a dominant plant species in subalpine meadows on the low-latitude plateau,it is of great guiding significance to clarify the habitat characteristics and key growth factors of different slope positions of Arundinaria faberi for its community protection.The research object was Arundinaria faberi in the subalpine meadow of Gaoben Mountain in Xundian,Yunnan.By investigating the characteristics of growth and habitat factors of Arundinaria faberi in different slope positions,the key growth factors of Arundinaria faberi were identified by correlation heat map.The results showed that:1) The air temperature and relative humidity tended to decrease with the increase of the slope position,while the wind speed and solar radiation intensity increased with the increase of the slope position.2) The soil particle composition of different slope positions was mainly composed of silt particles.The soil bulk density increased with the increase of the slope position.The soil moisture content,large aggregate content and soil chemical indicators all increased first and then decreased with the increase of the slope position.The meadow soil was obviously acidic,and the soil quality level reflected by the physical and chemical characteristics of the middle slope soil was relatively higher.3) With the increase of the slope position,the morphology and community characteristics of Arundinaria faberi showed a significant deterioration trend.4) Correlation heat map analysis showed that air temperature,solar radiation intensity,wind speed,soil bulk density and available phosphorus had a great influence on the corresponding growth characteristics of Arundinaria faberi among which air temperature,solar radiation intensity,wind speed and soil bulk density were the most influential key factor for growth. Table and Figures | Reference | Related Articles | Metrics

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Habitat Suitability Assessment of Moose Based on Combined MaxEnt and HSI Model ZENG Haowei, LING Chengxing, ZHANG Jun, LIU Hua, ZHAO Feng, JIN Yue, LIU Shuguang, ZHANG Yutong FOREST RESOURCES WANAGEMENT    2023, 0 (4): 115-122.   DOI: 10.13466/j.cnki.lyzygl.2023.04.014 Abstract （326）   HTML （11）    PDF （3281KB）（2379）       Knowledge map    Save Moose is a national first-class protected animal in China.Studying the habitat quality of moose is a key step to protect moose population.In this paper,taking Heilongjiang Nanwenghe National Natural Reserve as an example,the habitat suitability of moose was evaluated using maximum entropy model(MaxEnt)and habitat suitability index(HSI)model.Moose distribution points data was gathered from unmanned aerial vehicle transect survey,the maximum entropy model was used to get the environmental factor contribution and single environment variable response curve,combined with natural geography of the Reserve,the evaluation model was set up based on the impact of different environmental factors on moose to evaluate the moose habitat suitability of reserve quantitatively.The results showed that altitude(20.3%),slope(11.4%)and distance from river(11.3%)were the main environmental factors affecting the habitat distribution of moose,while slope aspect,slope position and vegetation coverage had less effect on moose habitat.Moose prefer to live in forested area with low altitude,moderate slope,sunny slope,and prefer to live close to river,far away from human disturbance and in areas with high coverage.In the reserve,the area of high suitable habitat for moose is 424.6 km2,accounting for 18.5% of the total area.The area of low suitable habitat is 1 422.9 km2,accounting for 62% of the total area.The area of unsuitable habitat is 447.5 km2,accounting for 19.5% of the total area. Table and Figures | Reference | Related Articles | Metrics

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Analysis of General Status and Examination of Estimation Errors for One-Variable Tree Volume Tables in China ZENG Weisheng, YANG Xueyun FOREST RESOURCES WANAGEMENT    2023, 0 (2): 43-49.   DOI: 10.13466/j.cnki.lyzygl.2023.02.006 Abstract （580）   HTML （22）    PDF （1271KB）（2247）       Knowledge map    Save Tree volume tables are important basic tools in forest inventory and monitoring.One-variable tree volume tables have been used in continuous forest inventories (CFIs) of China for more than 40 years,but we have never systematically tested the applicability in nowadays.In this paper,the general status of currently used one-variable tree volume tables were analyzed from the aspects of quantity,zoning,tree species,and model type;and most of one-variable tree volume tables were examined by using the tree height data of 138 911 sample trees.The results showed that the total number of one-variable tree volume tables used in China's CFI reached 707,and the number of provincial volume tables varied greatly,from 3 to 171;there were 18 provincial regions divided into several modeling populations,while others were based on whole provincial regions;there were also great differences in the number of tree species groups for developing tree volume tables in each provincial region,with the least being 3 and the most being 31;a total of 25 models were used to develop tree volume tables,but nearly 90% of the tree volume tables were based on 5 models;about 70% of the one-variable tree volume tables exceeded the allowable error limit of ±5%,and 10 of 31 provincial regions and four forest industry groups exceeded the range of ±10% of the volume estimation errors,among which the maximum negative bias was -14.86% and the maximum positive bias was 23.22%.Based on the results of analysis,it is suggested that at the end of this inventory,a comprehensive and systematic applicability test should be carried out on the current one-variable tree volume tables;and unified revision should be made on the tree volume tables with significant deviation,so as to optimize and adjust the division of modeling populations,tree species grouping and the volume model type;and the change of volume estimation method from one-variable table to two-variable table should be actively promoted. Table and Figures | Reference | Related Articles | Metrics

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Information Extraction and Security Risk Assessment of Street Trees Based on Vehicle-Borne LiDAR Data MU Tianbao, WU Linna, ZHANG Haitao, ZHANG Han FOREST RESOURCES WANAGEMENT    2022, 0 (5): 91-98.   DOI: 10.13466/j.cnki.lyzygl.2022.05.012 Abstract （338）   HTML （8）    PDF （6310KB）（2059）       Knowledge map    Save Rapid and accurate acquisition of the structural characteristics and safety risk status of urban street trees based on LiDAR point cloud data is of great significance to assist smart city management.In order to solve the problem that LiDAR point cloud data is difficult to segment regions with unclear morphological characteristics in street tree parameter acquisition,a individual tree extraction method based on circular index of trunk center point was proposed.Firstly,it obtained the sliced point cloud of the trunk layer according to the elevation information,then,segmented the sliced data based on the improved DBSCAN clustering algorithm.Secondly,it identified the trunk through the morphological characteristics of the ground features and obtained the central point,so as to complete the extraction through the circular index method based on the central point.Finally,it combined with the risk matrix method to evaluate the safety risk of the stability and traffic impact of the street trees in the study area.The results showed that the proposed individual tree extraction method could effectively improve the segmentation accuracy of individual trees of street trees in areas with unclear morphological characteristics,and accurately obtain the structural parameter information such as the number,shape and position of street trees;The safety risk assessment found that the stability of most street trees and the risk of traffic impact in the study area werein a level I negligible risk state,but there were some street trees whose stability and risk of traffic impact were level II and level III.These trees were mainly distributed in the area with dense and interlaced roadside trees in the study area.The results can provid corresponding decision support for relevant departments to monitor street trees in a timely and effective manner. Table and Figures | Reference | Related Articles | Metrics

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Geographic Weighted Regression Model Combined with Remote Sensing for Estimating Forest Aboveground Carbon Storage of Songyang County ZOU Weimin, CHEN Chao, HUANG Lei, SONG Meixuan, LI Xuejian, DU Huaqiang FOREST RESOURCES WANAGEMENT    2023, 0 (4): 132-140.   DOI: 10.13466/j.cnki.lyzygl.2023.04.016 Abstract （296）   HTML （9）    PDF （5877KB）（2033）       Knowledge map    Save Aboveground carbon(AGC)is an important indicator of the basic characteristics of forest ecosystems and a theoretical basis for evaluating the functional structure and productive potential of forests.As one of the nine key forestry counties in Zhejiang Province,Songyang County has a very important ecological status,so the accurate estimation of forest AGC in Songyang County is an important reference value for the stability evaluation of forest ecosystems and forest management in Songyang County.However,Songyang County is dominated by medium and low hilly areas surrounded by mountains,and how to consider the influence of complex terrain on the temporal and spatial variation of AGC is an urgent problem to be solved to achieve accurate estimation of AGC in mountainous forests.Therefore,based on Landsat TM satellite imagery and forest AGC survey data in Songyang County,a geographically weighted regression model(GWR)combined with spatial variation characteristics was constructed to estimate forest AGC,and compared with the results of ordinary least squares(OLS),finally,the optimal model was selected to predict forest AGC and its spatial distribution in Songyang County.The results were asfollows:Texture information from Landsat TM satellite imagerywas important for predicting forest AGC in Songyang County;The GWR model accurately estimated the AGC and spatial distribution of forests in Songyang County,and improved the accuracy by 9% over the OLS model,with an R2 of 0.71.The total AGC of forests in Songyang County was 3.901×106 Mg,with an average AGC of 23.70 Mg/hm2,accounting for about 10% of the total AGC of forest vegetation in Lishui City,which had a relatively important position in serving regional ecological functions.The study will provide advanced technical tools for accurate estimation of forest AGC in Songyang County,as well as scientific data for evaluating the function of forest carbon sink in Songyang County. Table and Figures | Reference | Related Articles | Metrics

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Main Results of the Fourth Rocky Desertification Survey in Karst Area and Analysis of Rocky Desertification Control Situation NING Xiaobin, WU Xiebao, HUANG Junwei, WU Houjian, LIU Wei, PENG Xi FOREST RESOURCES WANAGEMENT    2023, 0 (3): 9-14.   DOI: 10.13466/j.cnki.lyzygl.2023.03.002 Abstract （813）   HTML （41）    PDF （972KB）（1694）       Knowledge map    Save The fourth rocky desertification survey in Karst area was based on the result of the third national land survey,while taking 2021 as the base year to comprehensively investigate the condition and change of the rocky desertification land China.This paper briefly introduced the basic situation of the fourth rocky desertification survey,the present situation and dynamic change of rocky desertification land,as well as analyzed the current situation of rocky desertification control,and put forward countermeasures and suggestions.The results showed that,the rocky desertification land area was 7.223 million hm2 by 2021.Compared with 2016,the net decrease of rocky desertification land area was 3.331 million hm2,while the average annual decrease was 0.666 million hm2.The main results indicating that the rocky desertification land in China presents the overall evolution direction of "area decreasing,degree reduction and ecological condition being stable ". Table and Figures | Reference | Related Articles | Metrics

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The Resource Status and Conservation Strategies of National Key Protected Wild Plants in China JIANG Yafang, TIAN Jing, LIU Zengli, MA Wei, SHAO Wei, BAI Ling FOREST RESOURCES WANAGEMENT    2023, 0 (4): 1-10.   DOI: 10.13466/j.cnki.lyzygl.2023.04.001 Abstract （820）   HTML （66）    PDF （1248KB）（1664）       Knowledge map    Save Accurate data on the population and survival status of wild plant are the basis for the plant diversity conservation.The Regulations of the People's Republic of China on the Protection of Wild Plants make it clear that the wild plants administrative departments should periodically organize surveys of national key protected wild plants,and establish wild plants resource archives.Therefore,China launched the second national survey of national key protected wild plants in 2012.Based on the survey data,the population,community area and in situ conservation status of 283 species of national key protected wild plants in China are reported.Reasons for the changes of wild plant resources over the past 10 years are also discussed through comparative analysis between the first and second national survey of national key protected wild plants.In order to advance conservation and management of wild plants in China,several countermeasures and suggestions were put forward,including establishing a national platform for wild plant supervision and management,improving the plant diversity conservation system,and carrying out the wild plant rescue and conservation projects. Table and Figures | Reference | Related Articles | Metrics

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Biodiversity Conservation and Practice in National Wetland Park—A Case Study of Xixi National Wetland Park HU Xinting, YUAN Jun, CHENG Yonqquan, GUO Fengyi, YUAN Weiying, LI Gang, YANG Yongfeng Forest and Grassland Resources Research    2024, 0 (2): 133-140.   DOI: 10.13466/j.cnki.lczyyj.2024.02.016 Abstract （521）   HTML （13）    PDF （1015KB）（1609）       Knowledge map    Save China established its first National Wetland Park in 2005.As an indispensable component of wetland protection system in China,national wetland parks have significantly contributed to biodiversity conservation over the past two decades.This study examines the significant challenges national wetland parks face in current biodiversity conservation and outlines key strategies for biodiversity conservation planning.Taking Xixi national wetland parks as a case study,it demonstrates specific practices in biodiversity conservation,particularly in rare and endangered species conservation,watershed biodiversity demonstration and nature education.This study proposes strategies for the key directions of biodiversity conservation in national wetland parks,which include protecting and restoring the biological baseline resources of wetlands,wild plant and animal habitat restoration,establishing information system for wetland sensing and monitoring,and promoting scientific and rational utilization of biological resources.These strategies aim to facilitate the development of national wetland park and enhance the quality of wetland biodiversity conservation in the new era. Table and Figures | Reference | Related Articles | Metrics

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Discussion on the Technical System of Forest Fire Risk Assessment JIANG Chunying, YANG Xueqing, ZHANG Guoli, SUN Zhichao, JIANG Yun'an, JIANG Aijun FOREST RESOURCES WANAGEMENT    2023, 0 (2): 17-26.   DOI: 10.13466/j.cnki.lyzygl.2023.02.003 Abstract （627）   HTML （21）    PDF （1228KB）（1446）       Knowledge map    Save The risk assessment index system of forest fire was constructed by comprehensively utilizing the hazard of forest fire,the exposure and vulnerability of disaster bodies.The hazard of disaster was based on the contents of combustibles,meteorological conditions,field fire sources,terrain and topography,the exposure of disaster bodies was based on the contents of above-ground living biomass,number of buildings,population,GDP,and the vulnerability of disaster bodies was based on the proportion of flammable forest land,proportion of combustible building area,proportion of the elderly and young population,vulnerability of economic activities.Using The Analytic Hierarchy Process and expert scoring,this paper determined the weights of each evaluation indicator.It refined the accuracy of forest fire risk assessment to multiple spatial scales such as small class,30 arc second geographic grid,township level,county level,etc.to meet the accuracy requirements of forest fire prevention management at different administrative levels of the country,province,city,and county.At the same time,this paper proposed the best solution for forest fire risk identification in different regions and periods. Table and Figures | Reference | Related Articles | Metrics

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Spatio-Temporal Pattern Analysis of Vegetation NPP in Yunnan Province Based on Improved CASA Model QIAN Hui, ZHANG Chao, FAN Jinming, DENG Zaichun, ZHU Xiali, LI Chengrong Forest and Grassland Resources Research    2023, 0 (6): 120-128.   DOI: 10.13466/j.cnki.lczyyj.2023.06.015 Abstract （254）   HTML （11）    PDF （4149KB）（1273）       Knowledge map    Save Vegetation net primary productivity (NPP)is one of the indicators to measure the level of ecosystem productivity,it is of great significance to estimate it by using the combination of ecology and remote sensing.In this study,we applied the improved CASA model;based on the MODIS vegetation index product,meteorological data,and land cover data;estimated the vegetation NPP in Yunnan Province in 2000,2005,2010,2015,and 2020,and explored its spatial distribution characteristics using the Moran's I index,Getis-Ord Gi* hotspot analysis,and overlaying analysis with China's ecologically Functional Protected Areas in China were superimposed and analyzed.The results showed that:1)the vegetation NPP in Yunnan Province in the past 20 years showed a trend of decreasing and then increasing trend,with an average value of 822.98 gc/(m2 a);the monthly vegetation NPP reached the highest in summer and the lowest in winter;and among the different vegetation types,the evergreen broadleaf forests had the highest NPP values.2)The spatial distribution of vegetation NPP decreased from south to north in each year,and the global spatial autocorrelation Moran 's I index was greater than 0.7.The NPP hot spots were mainly located in the southwestern border of Yunnan,and the cold spots were located in the northwestern and central urbanization areas of Yunnan.3)NPP hotspot areas superimposed with ecological function reserve intersected in Xishuangbanna Ecological Function Reserve and Southwest Karst Ecological Function Reserve,and the superimposed area accounted for 23%~26% of the total area of hotspot areas in each year.The study shows that NPP in Yunnan Province has shown a fluctuating upward trend in the past 20 years,and the results can provide scientific references for vegetation monitoring and ecological environmental protection in Yunnan Province. Table and Figures | Reference | Related Articles | Metrics

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Study on Stand Spatial Structure of Typical Pinus massoniana Mixed Forest in Liping County of Guizhou Province YANG Shenjun, TAN Wei, CHEN Xinyu, TANG Jiajun, YANG Zejun, WU Yujie FOREST RESOURCES WANAGEMENT    2023, 0 (3): 105-114.   DOI: 10.13466/j.cnki.lyzygl.2023.03.014 Abstract （309）   HTML （6）    PDF （3320KB）（1198）       Knowledge map    Save This paper explored the spatial structure characteristics of typical mixed forests of Pinus massoniana in Liping County,Guizhou,and provided theoretical basis for the management and transformation of mixed forests in this area.Taking Pinus massoniana in the mixed forest in Liping County as the research object,the typical Pinus massoniana mixed forest in the study area was divided into 7 forest types based on the mixed tree species and proportion.The types were broad-leaved mixed forest with Pinus massoniana propotion of 40%(type A),50%(type B),70%(type C) and coniferous mixed forests mixed with Chinese fir with Pinus massoniana propotion of 30%(type D),50%(type E),70%(type F) and pure forests of Pinus massoniana(type G).The spatial structure of all types were analyzed using comprehensive evaluation indicators such as angular scale,diameter at breast height ratio,tree height ratio,mingling degree and spatial structure.The results showed that:1) The seven types of Pinus massoniana stands in the study area were all in a light aggregation distribution state,tending to a random distribution pattern;2) The Pinus massoniana in type F of the study area had a moderate height and diameter at breast height,while the Pinus massoniana in other types were subdominant in height and diameter at breast height;3) The mingling degree in the Pinus massoniana mixed forest in the study area was relatively high,usually above moderate mingling degree,while the pure forest of Pinus massoniana was in weak mingling degree and nearly zero mingling degree.4) The ranking of forest stand comprehensive evaluation was:Type A>Type D>Type E>Type B>Type F>Type C>Type G;5) There was no significant difference in the spatial structure of typical Pinus massoniana in the study area in terms of angular scale,ratio of diameter at breast height to size,and ratio of tree height to size.The differences in spatial structure were mainly influenced by the mingling degree.The mixed forest as a whole qas developing towards a top level community with random distribution,moderate competition among trees,and higher mingling degree,but it had not yet reached the level of natural top level community. Table and Figures | Reference | Related Articles | Metrics

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Tree Level Monitoring of Pine Wilt Disease Based on UAV Multispectral Imagery WANG Bu, TAN Wei, WANG Guilin, PU Xiuqing FOREST RESOURCES WANAGEMENT    2022, 0 (5): 107-117.   DOI: 10.13466/j.cnki.lyzygl.2022.05.014 Abstract （567）   HTML （21）    PDF （6334KB）（948）       Knowledge map    Save Pine wilt disease(PWD)is one of the most harmful forest diseases,and there is an urgent need to adopt accurate monitoring means to determine the number and location of diseased trees for efficient prevention and control of PWD.In this study,the image of PWD epidemic area in Zhongcheng Town,Rongjiang County,Guizhou Province was obtained by using multi spectral UAV,and the multi spectral UAV and its derived point cloud were used as data sources.Firstly,localization identification and crown profile segmentation of individual trees in the study area were performed by point cloud segmentation algorithm.The spectral features were then extracted in segmentation units and the best feature set was filtered by a combination of random forest and recursive feature elimination(RF-RFE).Finally,random Forest(RF)and support vector machine(SVM)detection models were constructed based on screening feature sets,and the model detection performance was evaluated. At the same time,the RF and the SVM were used to invert the disease susceptibility in the study area and draw the spatial distribution map of PWD.The following key results were obtained:1)The individual trees segmentation based on photogrammetric point clouds was effective,with an overall F-score value of 82.21%.The OA and Kappa of the RF model constructed after feature screening were 84.4% and 0.74,respectively,and the SVM was 76.09% and 0.66.2)The F-score for RF were 78.43%,69.23%,83.33% and 94.12%,SVM were 80.7%,55.81%,70.18% and 84.13% for the four stages of tree health,early,middle,and late detection,respectively.The comprehensive comparison of the detection performance of RF was the best.The study pointed out that it was feasible to use the combination of UAV multispectral image and photographic measurement point cloud for individual trees scale monitoring of PWD.The study aimed to provide a reference for low-cost and accurate remote sensing monitoring of PWD. Table and Figures | Reference | Related Articles | Metrics

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Responses of Photosynthetic Characteristics and Water Potential of Alsophila spinulosa to Drought Stress and Rehydration LV Chaoyan, GAO Zhixi, XU Xingxian, WU Huan, CHEN Xingyan FOREST RESOURCES WANAGEMENT    2023, 0 (1): 51-61.   DOI: 10.13466/j.cnki.lyzygl.2023.01.007 Abstract （423）   HTML （7）    PDF （3540KB）（921）       Knowledge map    Save In order to clarify the adaptability of woody ferns to drought stress,3-year-old Alsophila spinulosa seedlings were selected for drought stress and rehydration treatment through potted water control.The changes of water potential and photosynthesis in the leaves of Alsophila spinulosa were studied after 3,6,9,12 days of drought and after 3,6,and 9 days of rehydration.The results showed that with the prolongation of drought time,the water potential of Alsophila spinulosa leaves showed an overall upward trend,the net photosynthetic rate (Pn) showed a downward trend,the inter-CO2 concentration (Ci) first decreased and then increased,and the stomatal conductance (Gs) and transpiration rate (Tr) showed a trend of decreasing-increasing-decreasing.In the early stage of drought (6 days ago),the change trend of Pn,Gs and Ci was basically the same,and the decrease of Pn was mainly caused by stomatal limitation.In the later period of drought (after 6 days),the change trend of Pn was inconsistent with that of Gs and Ci,and the decrease of Pn was mainly caused by non-stomatal limitation.After rehydration,Pn and Tr of Alsophila spinulosa leaves recovered to the level of adequate water supply,while the water potential,Gs and Ci recovered to the level above that of adequate water supply.At the same time,the water use efficiency (WUE) of Alsophila spinulosa leaves increased first and then decreased with the prolongation of drought time,and showed a downward trend after 6 days of drought.And after rehydration,the WUE basically recovered to the level of adequate water supply.Taken together,Alsophila spinulosa has relatively poor drought tolerance and relatively strong rehydration recovery ability.Through the analysis of the photosynthetic physiological characteristics of drought stress and rehydration process,it is preliminarily considered that Alsophila spinulosa is a drought-avoiding plant. Table and Figures | Reference | Related Articles | Metrics

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Summary on the Development of the Forest Management Plan TANG Xiaoping, OUYANG Junxiang FOREST RESOURCES WANAGEMENT    2022, 0 (zk1): 8-18.   DOI: 10.13466/j.cnki.lyzygl.2022.S0.002 Abstract （463）   HTML （6）    PDF （1001KB）（913）       Knowledge map    Save Since its emerging in France and Germany in the 17th century,the forest management plan has become the core system of sustainable forest management in the world after more than three centuries. China has introduced the forest working plan since the 1920s. In the course of more than 100 years,the theory,technologies and requirements of the preparation of forest management plan have been developing continuously. At present,China has formed the basic framework of forest management plan from the legal,technical and policy levels,and the system of the forest management plan has been preliminarily established for the preparation,review,approval,implementation,monitoring,evaluation,revision,adjustment and re-implementation. With the development and innovation of theories such as classified management,close to nature management,multi-functional management,ecosystem management and forest landscape restoration,some new application trends have emerged in the preparation and implementation of forest management plans in China. Relevant institutions and organizations have carried out the preparation and implementation of different types of forest management plans by applying different theories and technologies. New methods andtechnologies such as modeling,visualization,intelligence and cloud computing have also being gradually applied in decision-making and scheme preparation of the forest management. In particular,since 2019,guided by the theories of landscape ecology,ecological restoration and sustainable forest management,and with the main goal of restoring the integrity of the ecosystem and improving the function of forest ecological services,National Forestry and Grassland Administration has adopted scientific and optimized decision-making methods to carry out the preparation and implementation of new forest management plans for some state-owned forest farms in Jiangxi,Guizhou and Hebei,which have effectively expanded the theoretical support and application fields of China's forest management plans. Table and Figures | Reference | Related Articles | Metrics

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Forest Fire Risk Zoning Based on MaxEnt Model—A Case Study of Yantai Yellow and Bohai Seas New Area LI Jie, CHAO Bixiao, YAN Yuqian, JIANG Fan, ZHANG Dawei, SUN Yongkang, ZOU Quancheng Forest and Grassland Resources Research    2024, 0 (2): 8-16.   DOI: 10.13466/j.cnki.lczyyj.2024.02.002 Abstract （341）   HTML （24）    PDF （2259KB）（877）       Knowledge map    Save Forest fires are sudden and destructive natural disasters influenced by various factors such as meteorology,terrain,vegetation,and human activities.The establishment of a forest fire risk zoning is essential for effective prevention and controlling forest fires,which is of great significance for carrying out related work in the future.As a machine learning method,MaxEnt has gained widespread domestic and international usage in predicting probabilities of occurrences and identifying zoning of forest fire risk due to its demonstrated high accuracy.Yantai Yellow and Bohai Seas New Area,located at the junction of Jiaodong Peninsula and Yellow and Bohai Seas has a developed economy,high population density,and significant human impact on forests,making it representative of forest fire prevention efforts in China.This study took Yantai Yellow and Bohai Seas New Area as an example and utilized MaxEnt to predict the probability of forest fire occurrence and delineate forest fire risk zoning based on historical fire incident data,as well as dominant environmental variables such as meteorology,topography,land cover types,and socio-economic factors.The research findings indicate that:1)Dominant tree species(group)and population density have significant impacts on forest fire occurrence;2)In Yantai Yellow and Bohai Seas New Area,the areas with high,medium,and general risk levels are similar in size.High-risk areas are mainly concentrated in the southwestern mountainous region,while general-risk areas are primarily found along the northeastern coast.Through verification,this study's results have shown a high level of accuracy and can provide a methodological exploration for subsequent national forest fire risk zoning. Table and Figures | Reference | Related Articles | Metrics

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Research Progress on Invasion and Control of Invasive Alien Plant Dolichandra unguis-cati(L.)L.G.Lohmann. LUO Minxian, LIN Bihua, CAI Minghui, DONG Pengmin, LI Guoqiang, LIU Bao, ZHENG Shiqun FOREST RESOURCES WANAGEMENT    2023, 0 (2): 126-131.   DOI: 10.13466/j.cnki.lyzygl.2023.02.017 Abstract （325）   HTML （10）    PDF （1009KB）（857）       Knowledge map    Save Dolichandra unguis-cati is an invasive alien vine native to tropical America.It was first introduced into cultivation as an ornamental plant,and then,with the expansion of growing areas,it has seriously harmed the urban ecological landscape and species diversity.In recent years,with the economic globalization and climate change,D.unguis-cati has shown a serious invasion in the south,especially in some major coastal cities.If not prevented,it may develop into a serious invasive species.At present,there is little research on D.unguis-cati in China,and little understanding of its characteristics.On the basis of collecting relevant literatures at home and abroad,this paper summarized and analyzed the main research status of D.unguis-cati from three aspects:reproductive strategy,growth strategy and competition strategy.The results showed that tuber propagation strategy,motility,polyembryology,low leaf building cost and litter legacy effect were the main causes of the invasion.Through research and analysis,the purpose is to reveal the origin and general characteristics of the invasiveness of D.unguis-cati,and clarify the control technology and utilization value.At the same time,this paper explored the research blank points,in order to provide a reference for further in-depth study of the invasion characteristics of D.unguis-cati,to provide a scientific basis for early warning,control and value utilization. Reference | Related Articles | Metrics