Table of Content

    28 August 2021, Volume 0 Issue 4
    Integrated Management and Administration
    National Park System Leads the Mainstreaming of Biodiversity
    TANG Xiaoping
    2021, 0(4):  1-8.  doi:10.13466/j.cnki.lyzygl.2021.04.001
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    Mainstreaming of biodiversity is one of the most effective measures for biodiversity conservation and sustainable utilization.China has made great progress in the areas of in-situ biodiversity conservation,policy legislation,law enforcement and supervision,but it has not fundamentally contained the overall decline of biodiversity,mainly because biodiversity of China has not yet been fully mainstreamed,especially in the aspects of laws,economy,mechanism,technology and market,etc,which all need to be strengthened.Establishing a national park system is to innovate China’s natural ecological conservation system,including the establishment of a unified,standardized and efficient natural protected area management system,building the natural protected area system with national park as the main body,and the establishment of a new mechanism for the conservation of integrity and authenticity of the natural ecosystem.The establishment of a national park system in China is conducive to achieve the three major goals defined by the Convention on Biological Diversity,including protecting biodiversity,promoting the sustainable utilization of biodiversity components,and sharing the commercial benefits of genetic resources in a fair and reasonable manner.Judging from the national park system pilots that have been carried out,the 10 pilot sites have effectively led the mainstreaming process of biodiversity conservation in China.To this end,it is necessary to accelerate the establishment of a national park system,provide safeguard in laws,systems,and mechanisms,and form a long-term mechanism for mainstreaming biodiversity in terms of maintaining the boundaries of ecological security,as well as ecological governance,ecological compensation,and realizing the value of ecological products.

    Considerations and Recommendations for Establishing Insurance Mechanism for Protecting Endangered Species in China
    LI Wei, ZHOU Yu, XU Xiaowei, HUANG Baojian, Xiong Tieyi, LIU Shoucheng, HU Fuqiang, LIU Dingzhen
    2021, 0(4):  9-16.  doi:10.13466/j.cnki.lyzygl.2021.04.002
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    Endangered species of animals and plants are important components in the ecosystem.Their sustainable survival is threatened by many factors including both geology,weather and natural disasters in addition to anthropic activities.All those factors may impose uncertain risk of extinction on endangered species of animals and plants.This paper presented a comprehensive review on the current status and problems in conservation for endangered animal species of in China base on a bibliometric analyses on literatures in wildlife protection and management in last 45 years.It was proposed for the first time to establish and implement the insurance system for protecting endangered animal species by generalizing the history and experiences in practicing and implementing different wildlife and ecological associated insurances in last 10 years in China.The current necessity and importance to establish this endangered animal species insurance were analyzed and addressed.Potential questions associated with establishing and implementing this endangered species of animal insurance were also analyzed and discussed.Finally,the paper put forward countermeasures and suggestions for establishing the insurance mechanism.

    Practices and Exploration of Forest Ticket System Reform in Sanming of Fujian Province
    WANG Weibin, LI Shan
    2021, 0(4):  17-22.  doi:10.13466/j.cnki.lyzygl.2021.04.003
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    The key approaches to turn lucid waters and lush mountains into invaluable assets are to focus on core problems such as difficulty in discovering the value of forestry basic assets,low pricing efficiency,and poor liquidity,through the establishment and improvement of market-oriented forest resource value discovery mechanisms,product pricing mechanisms,and circulation trading mechanisms to gradually promote the capitalization of ecological resources,the securitization of ecological assets,and the marketization of ecological securities trading.Since the 19th National Congress of the Communist Party of China,Sanming has been implemented the spirit of General Secretary Xi Jinping's instructions on comprehensive deepening reform,especially the forestry reform in Fujian,explored the market-oriented mechanism for value discovery and realization of ecological products based on the reform concept of "lucid waters and lush mountains are invaluable assets" and continued to deepen the fourth round of forest reform with forest ticket system innovation as a breakthrough.Taking Sanming as an example,this paper summarized the pilot situation and main experience of the current forest ticket system reform,analyzed the current problems and expected benefits in the exploration of the forest ticket system in Sanming,and provided opinions and implementation suggestions for continuing to deepen the reform of the forest ticket system.

    The Analysis of Typical Forestry Financing Models in China and its Innovative Development
    LI Yaojun, WANG Ye, LIU Guobin, LIAO Ting, GUO Liqin, YAO Yanwu, CAO Jun
    2021, 0(4):  23-28.  doi:10.13466/j.cnki.lyzygl.2021.04.004
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    Forestry plays an important role in ecological civilization development,the innovative development of financing model of forestry is the key point in the modernization of forestry in China.By ways of literature review,material collection and data analysis,this paper summarized the current situation and development trend of financing model of forestry in China from the aspects of traditional financing models(the state direct investment,bank loans and foreign investment) and the innovation of financing models(forestry property mortgage loan,PPP financing model and BOT model).In addition,this paper also raised some suggestions to the innovative and healthy development of financing model of forestry from the aspects of establishing and improving policy and regulatory,improvement of professional property evaluation system and the establishment of financial market of forestry.

    Research on Coordinated Development of Carbon Market, Economic Growth and Environmental Protection in China's Carbon Trading Pilot Areas
    LI Kunyang, GU Guangtong
    2021, 0(4):  29-37.  doi:10.13466/j.cnki.lyzygl.2021.04.005
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    The coordinated development of carbon market,economic growth,and environmental protection is the fundamental safeguard to reach the goal of “carbon neutral 2060”.Based on the relevant data of China's seven carbon trading pilot areas from 2014 to 2019,this paper first developed the coordinated development degree index system of regional carbon market,economic growth and environmental protection,measured the coordinated development level,and finally,it used Tobit model to analyze the influences of industry firm number above regional scale,fixed asset investment,foreign direct investment and R&D investment on the coordinated development level.The results showed that:the coordinated development degrees of carbon market,economic growth and environmental protection in the pilot areas of carbon trading were on the rise,and Beijing and Guangdong were in good coordination,Tianjin,Shanghai,Shenzhen and Hubei were in intermediate coordination,and Chongqing was in primary coordination;There were significant differences in the positive and negative effects and levels of the industry firm number above regional scale,fixed asset investment,foreign direct investment and R&D investment on the coordinated development of carbon trading pilot areas.This paper provided decision reference for the unifying construction of national carbon markets,regional green economy development and the realization of carbon neutral goal.

    Research on the Impact of Forest Tenure Reform and Cadre-Farmer Relationship on Household’s Forest Land Tenure Securityl Perception in Rocky Desertification Area
    PANG Juan, RAN Ruiping
    2021, 0(4):  38-48.  doi:10.13466/j.cnki.lyzygl.2021.04.006
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    The households' forest land tenure security perception is a key factor affecting their participation in forestry management and ecological governance decisions.To explore the factors influencing the formation of households' forest land tenure security perception in rocky desertification areas under the new round of collective forest tenure reform,it has great significance to further improve the collective forest tenure system and guide reasonable forest management behavior and forestry ecological governance behavior of farmers in rocky desertification area.Taking 549 survey data of farmer households in Fengshan County,Hechi City,Guangxi,this paper used the ordered Logit model to estimate the impact of forest tenure reform and cadre-farmer relationship on the household’s forest land tenure security perception.The results showed that:1)The forest land registration and certificate had strengthened household’s forest land tenure security perception.However,due to the institutional environment of the implementation of forest reform policy,its strengthening effect was still limited in rocky desertification areas.In terms of the way of forest land registration,compared with evenly dividing shares and profits,registering forest land to households had more significantly improved the household’s forest land tenure security perception;2) The cadre-farmer relationship which represented by farmers' trust to village cadres,significantly improved the household’s forest land tenure security perception;3) The cadre-farmer relationship had a good moderating effect on the implementation of forest tenure reform policy.However,this moderating effect was weakened under the background of the current flattening of rural governance and the alienation of the relationship between farmers and village-level organizations.It may be an important way to improve the household’s forest land tenure security perception in rocky desertification area by further perfecting the forest tenure reform system and ensuring the implementation of the institutional policies with good cadre-farmer relationship.

    Analysis and Suggestions of Forest Pest Disaster Rate Index in China
    QIU Lixin, LU Xiuliang, FAN Shiqi, CHENG Tongtong, LIU Yang, CHANG Guobin
    2021, 0(4):  49-53.  doi:10.13466/j.cnki.lyzygl.2021.04.007
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    The forest pest control began to implement objective management since 1992,which is a reform of forest pest control and management method,and also a breakthrough in the understanding and concept of work.As an important index in objective management system,the forest pest disaster rate not only reflects actual disaster area size,moreover also represents effectiveness of prevention and control.Based on the objective management practice,this paper studied and analyzed the disaster rate.Then,it put forward countermeasures and suggestions for improving the forest pest disaster rate index in light of four aspects:to adjust the calculation method,to set the index value reasonably,to revise statistical standards and to standardize statistical methods.

    Scientific Research
    Modeling and Application Test of Larch Stand Volume Based on Aerial Lidar Point Cloud
    GAO Jinping, SUN Zhongqiu, YU Huina, GAO Xianlian, WU Fayun, LIU Yingchun
    2021, 0(4):  54-61.  doi:10.13466/j.cnki.lyzygl.2021.04.008
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    Based on the LIDAR point cloud and ground sample survey results obtained from the satellite-air-ground comprehensive test in the Northeast China Tiger and Leopard National Park,with emphasis on the larch(Larix spp.) case,this paper explored the laser radar survey mode method of larch forest volume model theory,and combined with the type 2 investigation results of key state-owned forest region of Inner Mongolia in northeast China.The results of the model were used to preliminarily calculate the hectare stock of some type 2 subcompartments of larch in this area,which was an effective attempt to apply the results of the Lidar research model in the direction of business application. From the model results and application test results in a small scale,larch forest stand volume precision of the model could meet the requirements of the forest resource planning and survey technology regulation,thus it can be applied in practice. To achieve truly scale business production and application,we need to make deep efforts in model precision,universality and scale application efficiency.

    A New Concept “Tree Species Mingling” for Mixed Degree of Stands Based on Tree Species Spectrum
    ZHANG Ke, FENG Sisi, HUANG Lang, LI Jianjun
    2021, 0(4):  62-68.  doi:10.13466/j.cnki.lyzygl.2021.04.009
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    Spatial segregation degree of tree species is an important content in the study of stand spatial structure,which is usually described by the mingling degree.The existing mingling degree indices only have the same species or different species results when describing the probability that the object tree and the nearest neighbor tree are different species,which cannot fully explain the mingling degree of tree species.Based on the traditional mingling degree and tree species pedigree relationship,the concept of tree species mingling degree was put forward in this paper.The traditional mingling degree and tree species mingling degree were compared and analyzed with 25 sample plots in 5 forest regions of Hunan Province,and the stand simulation and optimization were carried out by using tree species mingling degree.The results showed that there was a strong correlation between tree species mingling degree and traditional mingling degree,and tree species mingling can further refine the isolation degree of tree species in the structural unit,which can be used for the evaluation and optimization of stand spatial structure.

    Research on the Difference of Mingling Degree under Different Selection Schemes of Adjacent Trees
    QING Dongsheng, ZHANG Jiang, LI Jianjun, PENG Jinxiang, LIU Shuai
    2021, 0(4):  69-78.  doi:10.13466/j.cnki.lyzygl.2021.04.010
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    In order to clarify the difference of stand mingling degree under different adjacent tree selection schemes,and find the evidence of which stand type is suitable for different adjacent tree selection schemes,this paper can provide reference for the research of stand spatial structure related issues.31 sample plots were set up in Longhu Mountain of South Dongting Lake area according to the types of aggregated distribution stand,random distribution stand,uniform distribution stand and sparse distribution stand.The methods based on "1+4" nearest adjacent trees,radius R(R=3.05 m) circle and Voronoi diagram were used to solve the number of adjacent trees per plot,the mingling degree of single tree and the average mingling degree of stand in various places,and explore the correlation between different schemes in different forest types.1) From the point of view of the overall stand average mingling degree,the average mingling degree values of the other stands in the experimental plots were not greatly different,except that the average mingling degree value of the adjacent trees based on the radius R(R=3.05 m) circle in the sparse distribution was low.2) From the point of view of individual tree,the mingling degree values of target trees in different stand types were different under different adjacent tree selection schemes.3) The correlation between "1+4" nearest adjacent tree and Voronoi diagram was relatively high in different stand types.Different selection schemes of adjacent trees had their own advantages under different stand types,but on the whole,the stability and accuracy of the adjacent selection schemes based on "1+4" nearest adjacent tree and Voronoi diagram were relatively high in solving mingling degrees of different stand types.

    Effect of Forest Thinning on the Light Environmentof Quercus Variabilis Plantation and its Target Trees
    ZHANG Yanyan, WANG Qunxing, LUO Yusheng, LV Kangting, MA Ruiting, YAN Dongfeng
    2021, 0(4):  79-85.  doi:10.13466/j.cnki.lyzygl.2021.04.011
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    In order to explore the effect of forest thinning on the light environment of Quercus variabilis plantation and its target trees,two fixed plots(thinned and control plots,respectively) with the area of 1hm 2 were established in 40a Quercus variabilis plantation in the Dengfeng Forest Farm,hemispherical photography and plant canopy analysis techniques were used to obtains the canopy images of the whole stand and the target trees,and the difference discipline of canopy structures and light environmental parameters between thinned and control plots.The results showed that the canopy openness and understory light radiation in thinned plot were significantly lower than those in control plot(P<0.05),and the leaf area index and light reduction rate were significantly higher than those in control plot(P<0.05).Canopy openness and understory light had significantly positive correlations(P<0.01),and the leaf area index was significantly negative correlated with the canopy openness and understory light(P<0.01).The average leaf area indexes of the target trees with the diameter of 14cm,16cm and 18cm in the thinned plot were lower than that in control plot(P<0.05),but the mean leaf angles and diffuse transmission coefficients of the target trees with 20cm diameter in thinned plot were significantly higher than those in control plot(P<0.05).Forest thinning improved the forest canopy structure,enhanced the intensity of understory light,and the target tree photosynthesis effective radiation increased,photosynthesis capacity improved.The research results have certain reference value for the cultivation of large-diameter timber in the Quercus variabilis plantation and the formulation of artificial measures to promote natural regeneration.

    Landscape Design of the Fifth Facade of Daxing International Airport
    LI Yanbin
    2021, 0(4):  86-93.  doi:10.13466/j.cnki.lyzygl.2021.04.012
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    The emergence of high-rise buildings,the development of aviation industry and the increase of UAV ownership of ordinary people provide more opportunities for people to overlook the fifth facade of the city.In 2020,Beijing issued the "Guidelines for Urban Design of the Fifth Facade and Landscape Overlooking System in Beijing".It is urgent to explore the green landscape design method of the fifth facade.Based on the research of a large number of documents,combined with the green landscape design of the take-off and landing area of Beijing Daxing International Airport,this paper probed into the design strategy of earth art,and made it clear that earth art played a positive role in the green landscape construction of the fifth facade of the city.In China,it was the first time to practice the earth art design in the airport area.

    Correlation Analysis of Fine Particulate Pollutants and Land Cover Landscape Pattern in Beijing
    MA Bolun, WANG Lei, HUA Yongchun
    2021, 0(4):  94-103.  doi:10.13466/j.cnki.lyzygl.2021.04.013
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    Air pollution is a key environmental issue nowadays.It is of great significance to understand the interaction between different land cover landscape patterns and air fine particulate pollutants for improving urban ecological environment.Aerosol optical depth(AOD) is the premise of the generation of fine particulate pollutants in the air.The AOD data measured by the AERONET ground monitoring points in Beijing and the surface fine particulate pollutants data were used for fitting analysis,and then the AOD of four seasons in Beijing was retrieved by using MODIS data.The Landsat8 image was processed to obtain the landscape type index of Beijing in 2018,and the correlation analysis was conducted with four seasons AOD data.The results showed that:1) fine particulate pollutants were negatively correlated with LPI(maximum patch index),ED(boundary density),COHESION(patch connectivity) and AI(patch aggregation),but positively correlated with PD(patch fragmentation) and LSI(landscape shape index);2) The annual forest and grassland were the core types with significant negative correlation with fine particulate pollutants,while the correlation between farmland and water body was significantly related to seasonal changes;3) Multiple linear regression analysis was used to get the regular model of forest,grassland,farmland,water and fine particulate pollutants in four seasons,which further proved that landscape index could be used to estimate the mass concentration of regional fine particulate pollutants.

    Establishment and Optimization of Ecological Security Pattern in Bashang Area under the Background of "Two-District" Construction
    WANG Yanfang, DAI Tingji, Liu Mengzhu, PEI Hongwei, GUO Xiaonan
    2021, 0(4):  104-113.  doi:10.13466/j.cnki.lyzygl.2021.04.014
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    Bashang area in Hebei Province is the core area of the "two-district" construction for the capital city Beijing,its establishment and optimization of ecological security pattern is of great significance for sustainable ecological development in local area and region of Beijing,Tianjin and Hebei.Ecological sources were extracted from habitat quality index calculated by InVEST model based on the land use data of 2018.The minimum cumulative resistance model was selected to build the minimum cumulative resistance surface.This paper divided ecological security zones into different levels,extracted ecological corridors,and developed ecological security pattern of Hebei Bashang area.The results showed that(1) The habitat quality in Bashang area was generally low,with over 50% of the area at a low level and 46% at medium and high level,presenting the characteristics of polarization of habitat quality,and imbalance in type and distribution,etc.;(2) The ecological source area accounted for 17.50% of the total area of Bashang,and more than 40% of the ecological source area was distributed in Weichang Manchu and Mongolian Autonomous County;(3) The total length of the ecological corridor was 640.86km,and there were 53 ecological nodes.The ecological security zones of high quality in Bashang area accounted for 25.92%,and the ecological security zones of low quality were mainly distributed in Zhangbei County and Kangbao County.The quality of ecological security in Bashang was not very high,the diversity of ecological system was low,the distribution of ecological resources was not balanced in space,and the difference of ecological quality between counties and districts was obvious.In the future,the ecological quality of low-grade ecological regions should be further improved,and a more stable ecological security pattern should be established.

    Spatial Distribution Characteristics of Soil Nutrients in Semi-Arid Loess Hilly Area of Longzhong
    CHAI Chunshan, WANG Ziting, ZHANG Yangdong, QI Jianli
    2021, 0(4):  114-120.  doi:10.13466/j.cnki.lyzygl.2021.04.015
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    In order to provide scientific referencess for vegetation restoration and reconstruction in semi-arid loess area,the soil nutrients were measured and analyzed in 4 typical land use types(cropland,abandoned cropland,grassland,forestland) and 3 watersheds(Anjiagou,Longtan,Diaogou) in loess hilly area of Longzhong,Gansu Province.Variance analysis indicated that the soil nutrient content had no significant differences(P>0.05) among three watersheds except for total K,but had significant differences among different land use types(P<0.05);there were no significant differences(P>0.05) in soil nutrients between different slope aspects for cropland and abandoned cropland,also there were no significant differences(P>0.05) between different vegetations of forestland,but there were significant differences(P<0.05) between different vegetations of grassland.Variation analysis showed that there were small differences in nutrient variation among different watersheds,but great differences among different land use types.Correlation analysis showed that there was significant correlation among soil nutrients(P<0.05). The comprehensive analysis showed that in semi-arid loess hilly area,the geographical location of the watershed had no obvious influence on the content and distribution of soil nutrients,but the land use type had a great influence on the content and distribution of soil nutrients.Under the same land use type,slope aspect had no obvious influence on soil nutrient content and distribution,but the vegetation type had certain influence on soil nutrient content and distribution.The conversion of cropland to forestland and grassland was beneficial to the recovery of soil nutrients.

    Investigation of Wild Vine Resources in Pingtan and Analysis of Garden Application
    PENG Te, CHEN Yuelin, WANG Fang, XIONG Kuanhong, MA Xiaodi, DENG Chuanyuan
    2021, 0(4):  121-129.  doi:10.13466/j.cnki.lyzygl.2021.04.016
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    Taking the wild vine resources on the main island of Pingtan and surrounding islands as the research object,the sampling method was used to conduct field investigation and collection,and the TOPSIS method was used to comprehensively evaluate and analyze the development and utilization of vine resources in the study area.The results showed that there were 37 species of vines in Pingtan,belonging to 18 families and 32 genera.There were many single families.Leguminosae and Vitis were the dominant families.Wild vines were mainly composed of genera with only one species,accounting for the total 87.50% of the genera;dicotyledonous wild vines accounted for 94.59%,with obvious advantages.Monocotyledonous vines and fern vines were relatively poor in species;climbing methods were mainly winding,accounting for 75.68%,tendrils,adsorbents,barbs and other trailing species accounted for less.Thirty species of vines with excellent comprehensive evaluation results were selected,such as Parthenocissus semicordata,Parthenocissus tricuspidata,Vitis bryoniifolia,Cayratia japonica,Smilax china,Calystegia solderanella,Canada rosea,etc.,which can be applied to three-dimensional gardening.In addition,based on the actual situation in Pingtan,the application methods of corresponding vines in gardens and the development and protection suggestions were put forward.

    Study on Distribution Characteristics and Population Dynamics of Wild Cycas Hainanensis in Hainan Island
    WU Erhuan, LI Donghai, YANG Xiaobo, ZUO Yongling, YANG Ning
    2021, 0(4):  130-137.  doi:10.13466/j.cnki.lyzygl.2021.04.017
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    In order to recognize the distribution characteristics and population dynamics of Cycas Hainanensis resources in Hainan,a general investigation of wild Cycas Hainanensis was conducted in 56 sites and 62 quadrats in Hainan Island.The geographical distribution,population characteristics,population distribution pattern and the influence environmental factors of wild Cycas Hainanensis population were studied.The results showed that: 1) the investigated regional distribution of Cycas hainanensis mainly included Wuzhishan city,Baoting county and Qiongzhong county etc in central and southern mountain cities and counties,and the southeast mountain areas of Changjiang county;2) Cycas Hainanensis was mainly distributed in tropical rainforests with a medium and high elevation range of 400~800m,slope range for the semi-sunny,semi-shady slope area,and a medium and higher canopy density range of 40%~60%,the terrain was flat,usually in moist biotopes such as under story and the bush of forest edge,and the ravine side;3) The Cycas Hainanensis population structure was stable,as the young trees and small trees were in the majority,and the big trees were fewer,and seedlings were the least,its renewal ability was not strong;4) It was indicated by the stationary life table that the population mortality was increasing with age,the survival curve of Cycas Hainanensis population closed to Deevey-Ⅰ type;5) The population distribution had a tendency to uniform distribution.

    Technical Application
    Comprehensive Experiment Substitute for Multi-Payload Data of Terrestrial Ecosystem Carbon Inventory Satellite in Hainan
    LIU Yingchun, WU Fayun, SUN Zhongqiu, FU Anmin, GAO Jinping, GAO Xianlian, GAO Jianxin, CUI Chenyan, CHAO Zhi
    2021, 0(4):  138-148.  doi:10.13466/j.cnki.lyzygl.2021.04.018
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    Hainan conserves one of the last tropical rainforests in China. The space-air-ground comprehensive data in tropical forest is not only the basis of the management of National Park of Hainan Tropical Rainforest,but also an important component to set up methodology of Terrestrial Ecosystem Carbon Inventory Satellite (TECISat) in China. From March 20,2020 to July 10,2021,we used National Forest and Grassland Inventory (NFGI) airborne platform to produce 20TB raw data and products that covered an area more than 6000 km2,including airborne large-footprint LiDAR,small-footprint LiDAR,visible and near-infrared image,and ultra-spectrum image. We also collected data from 170 forest plots,183 ground control points and 17 checking polygons. Combined with GF-7 and GEDI data,these data constituted the space-air-ground data covering National Park of Hainan Tropical Rainforest and surrounding area. The products showed that the horizontal and elevation accuracy of large-footprint LiDAR were better than 1m and 0.15m respectively. The horizontal and elevation accuracy of small-footprint LiDAR were better than 0.5m and 0.08m respectively. The elevation accuracy of DEM and height precision of CHM were 0.15m and 91.8% respectively. The horizontal accuracy of 0.2m DOM was better than 0.5m. The spectral and spatial resolution of ultra-spectrum image were 0.24nm and 1~2m respectively. This experiment provided high quality products and space-air-ground data for TECISat and national park management.

    Effects of Polyaspartic Acid Water-Retaining Agent on Photosynthetic Characteristics of Populus euphratica
    ZHU Mengzhen, HAN Lu, DAI Yaqi, MA Xiaoyan, FENG Yu, ZHANG Dandan
    2021, 0(4):  149-156.  doi:10.13466/j.cnki.lyzygl.2021.04.019
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    Moisture is the key factor affecting the success or failure of desert vegetation restoration and afforestation in arid area.The experiment was carried out in mid-August 2020 at the experimental station of Tarim University in Alar City,Xinjiang Autonomous Region.Two-year-old seedlings of Populus euphratica,a key ecological species in the Tarim desert,were used as test materials,and a randomized block test was used in the field.This paper studied the effects of different dosages of polyaspartic acid water retention agent(PASA) on the growth,photosynthetic gas exchange and photosynthesis-light characteristics of Populus euphratica seedlings.The results showed that PASA significantly improved the leaf and soil water content of Populus euphratica,especially those treated with PASA 10g/plant were the highest,and the mean value of PASA 10g/plant were 6.11% and 483.54% higher than that of CK(without PASA) respectively.The diurnal variation of net photosynthetic rate(Pn),stomatal conductance(GS) and transpiration rate(Tr) showed an "M" variation,and instantaneous water use efficiency(WUEinst) showed an "L" variation,showing an obvious photosynthetic nap phenomenon.The peak values of Pn,GS and Tr were all higher than those of CK.Pn,Gs,Tr,WUEinst,apparent quantum efficiency(AQY),light saturation point(LSP),maximum net photosynthetic rate(Pnmax),total biomass(TB) and stomatal length(SAL) of Populus euphratica treated with PASA 10g/plant were 27.48%,50%,20.84%,18.99% 87.14%,88.90%,31.93%,230.54%,22.95% higher than those of CK respectively.The results showed that the photosynthetic efficiency,biomass and instantaneous water use efficiency of Populus euphratica were significantly improved,and the illumination ecological amplitude was expanded.Therefore,the recommended dosage of PASA for afforestation in arid area is 10g/plant.

    Estimating Standing Volume in Southern Collective Forest Region Based on the Unmanned Aerial Vehicle LiDAR Characteristic Variables
    DU Zhi, CHEN Zhenxiong, MA Kaisen, LIU Ziwei, GU Xinggui
    2021, 0(4):  157-165.  doi:10.13466/j.cnki.lyzygl.2021.04.020
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    Based on the annual monitoring and evaluation data of forest resources in Guangxi Zhuang Autonomous Region,the characteristic variables of airborne LiDAR were selected with the stepwise regression,and multiple linear regression,logistic regression and random forest models were established to predict the volume of sample plots of Eucalyptus robusta,Cunninghamia lanceolate and natural broad-leaved forest in southern collective forest region.The results showed that:1) For the plots of Eucalyptus robusta and Cunninghamia lanceolate,the stepwise regression characteristic variables were mainly height and intensity variables,while for the natural broad-leaved forest plots,they were comprehensive variables,such as clearance ratio,coverage,and leaf area index;2) For Eucalyptus robusta and natural broad-leaved forest plots,the estimation accuracy( Eucalyptus robusta:R 2=0.97,RMSE=12.60 m3/hm2;natural broad-leaved:R2=0.90,RMSE=18.45 m3/hm2) of the volume of the random forest model was higher than that of the multiple linear regression and logistic regression models,for the Cunninghamia lanceolate plot,the multiple linear regression model obtained the best estimation result(R 2=0.91,RMSE=24.30 m3/hm2);3) Among the estimation accuracy of the three models,the artificial Eucalyptus robusta and Cunninghamia lanceolate plots were higher than of the natural broad-leaved forest plots.It can be seen that the high-density LiDAR point cloud can obtain better characteristic variables.In view of the complex sample plot conditions,we need to flexibly select the estimation model to realize the volume survey,which can provide a scientific basis for the forestry and grassland authorities to carry out the forest resources survey,monitoring and management.

    Research and Application Progress of Computer Automatic Extraction of Forest Land Sub-Compartment Boundary and Topographic Factors
    CHEN Yongfu, CHEN Qiao, LIU Hua
    2021, 0(4):  166-172.  doi:10.13466/j.cnki.lyzygl.2021.04.021
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    Forestland sub-compartment(referred to as sub-compartment) is the basic unit of forest resources planning,design,investigation,statistics and management.Sub-compartment survey is an important basic work in forestry,and sub-compartment boundary and topographic factors play a key role in sub-compartment survey.Therefore,it is very important to obtain the boundary and topographic factors of sub-compartment quickly and accurately for compiling forest management plan and guiding forestry production.Through collation of the research and application status of computer automatic extraction method of sub-compartment boundary based on remote sensing image,digital elevation model(DEM),remote sensing image combined with DEM,and computer automatic extraction method of elevation,slope,aspect,slope position and other topographic factors based on DEM,this paper pointed out the existing problems,and provided some suggestions for future research.