Table of Content

28 April 2021, Issue 2

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Analysis on Factors Influencing Willingness of Farmers with Cropland to Forest Program to Resume Farming in 19 Provinces

ZHOU Yinhua, ZHAO Youxian, HU Yanjie, ZHANG Kun, WANG Lanhui

2021,(2):  1-10.  doi:10.13466/j.cnki.lyzygl.2021.02.001

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In this paper,the logistic regression model was applied to analyze the influencing factors affecting the willingness of fallow farmers to resume farming based on 1 638 valid questionnaires collected from the field research.The results showed that the factors affecting the willingness of farmers to return to farming in the two rounds were different;the willingness of farmers to return to farming in the previous round was influenced by the condition of the fallow land,such as the fallow forest species,the preservation rate of fallow forest land and the income of fallow land and the willingness of farmers to return to farming in the new round was significantly influenced by the fallow subsidy standard.There were significant differences in the willingness of different groups of fallow farmers to return to farming,such as the willingness of ethnic groups and low-income households to return to farming.The willingness of farmers to return to farming is different in different terrains and regions.For example,farmers in hilly and mountainous areas in the previous round are more willing to return to farming,while farmers in the northwest of the new round are more willing to return to farming.In order to effectively consolidate the results of fallow forests and prevent the phenomenon of replanting,more flexible support policies should be formulated,the quality of fallow forests should be improved and the economic potential of fallow forests should be explored.It also found that the social evaluation and farmers' recognition of the project should be improved by strengthening publicity.

Discussion on the Countermeasures for Ecosystem Conservation and Restoration of the Guangdong-Hong Kong-Macao Greater Bay Area

WANG Feng, CHEN Xingliang, ZHOU Xiaoguang, LIN Kunlun

2021,(2):  11-16.  doi:10.13466/j.cnki.lyzygl.2021.02.002

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Strengthening the protection and restoration of ecosystem is not only the basis for the ecological environment of the Guangdong-Hong Kong-Macao Greater Bay Area,but also an important target for the area to become a world-class bay area.Based on the literature research and field research,this paper analyzes and evaluates the present situation of the protection and restoration of the forest,wetland,city and marine ecosystem in the Greater Bay Area and tries to find existing problems.Based on the positioning of the Greater Bay Area,some countermeasures and suggestions are put forward,such as establishing a joint cooperation mechanism of ecosystem protection and restoration,scientifically determining the total amount of blue-green space and promoting the construction of ecological corridors.

Discussion on the Integrated Development Model of Economic Forest and Research Travel Industry

CHEN Mingzhu, QIN Yi, LI Ximei

2021,(2):  17-22.  doi:10.13466/j.cnki.lyzygl.2021.02.003

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As an important part of China's forest resources,economic forests are of great significance to the development and construction of the national economy,the protection of ecological balance and the development of the forest industry.This article aims to explore the transformation and upgrading of the economic forest industry structure by exploring the integration and development of the economic forest and the research travel industry,and to solve a series of supply-demand reversal problems in the current economic forest development process.The study takes Zhengzhou,capital of Central China's Henan Province,as an example in a bid to discuss its existing economic forest resources and development status.The PESTEL model is used to analyze the feasibility of integrated development.As a result,it is proposed that Zhengzhou's industrial integration design and development models can be divided into three categories:(1)According to the land management model,they are divided into:“company leasing+subcontracting”,“company+industry alliance”;(2)according to commercial investment entities:“school+tourism enterprise+government”,“school+professional research institute+government”;(3)According to the form of activity organization,it is divided into:“theme cognitive education”,“cultural experience activities”,“application practice exploration” and “ knowledge research learning”.

Research on Development of Poverty Alleviation via Grassland Tourism and Promoting Measures—A Case Study in Xiahe County of Gannan Tibetan Autonomous Prefecture in Gansu Province

LEI Xiao

2021,(2):  23-28.  doi:10.13466/j.cnki.lyzygl.2021.02.004

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The change of grassland resource function shifts its management mode and use function,and escalate the contradiction between protection and production.The development of grassland eco-tourism industry is a good way to alleviate this problem,which can promote the local economic development,help locals get rid of poverty,consolidate the achievements of poverty alleviation in grassland areas,and achieve the goal of rural revitalization.This paper selects Xiahe County,which has the typical characteristics of northern grassland,as the main research object,and takes the typical example analysis and research method—focusing on key problems—to solve the problem.Firstly,it puts forward problems existing in the current situation of tourism poverty alleviation,such as the lack of system,insufficient income,single way,narrow coverage and limited season.Then it puts forward five characteristics,including improving the poverty alleviation mechanism,integrating the linkage development,supporting the characteristic industries,broadening the publicity methods and developing the characteristic festivals,so as to effectively help the development of grassland tourism poverty alleviation in Xiahe County.At the same time,typical cases used in the study are expected to serve as inspiration to promote the development of national grassland tourism poverty alleviation.

Discussion on Methodology for Generating Annual Estimates in National Forest Inventory

ZENG Weisheng, XIA Rui

2021,(2):  29-35.  doi:10.13466/j.cnki.lyzygl.2021.02.005

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It is necessary to conduct national forest inventory and generating annual estimates of two binding targets,which are forest coverage and forest volume,for the annual examination and evaluation of green development targets and ecological civilization progress targets.Based on the data of 1 669 permanent plots of the 8^th and 9^th national forest inventories in Beijing,and according to the inventory plan “1/5 of plots being completed every year with a 5-year cycle”,five sets of sample plots were selected by systematic sampling and simple random sampling,respectively.The combined estimation method and double regression method were used to generate annual estimates of forest volume and the precision in the first year.The results show that the precisions of forest volume estimates from two methods are more than 90%. The study chose the 9^th inventory result of forest volume in Beijing as the base for comparison and found that the relative differences are between -1.93%~3.73% for the estimates based on combined estimation method,and the those are between -2.61%~4.98% for the estimates based on double regression method.The following conclusions can be achieved:The sample plots selected by systematic sampling are more representative than those selected by simple random sampling;Both combined estimation method and double regression method could be used to generate forest volume estimates for the first year and the subsequent years;Combined estimation method is more applicable and little better than double regression method,which can be used as an approximate simple method.

Study on Forest Landscape and Quality Improvement Based on Multiple Methods

ZOU Quancheng, XU Jiannan, FENG Xiaochuan, MU Xiaowei, HU Bin, LIU Hailing, KONG Fanli, WU Jing

2021,(2):  36-44.  doi:10.13466/j.cnki.lyzygl.2021.02.006

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With the continuous development of urbanization,the Niushou Mountain Cultural Tourism Zone,which was on the outskirt of Nanjing,East China's Jiangsu Province,has become a part of the city as it is the window of landscape and culture of Nanjing.However,the problems of its ecosystem,especially of the forests,are gradually emerging.In order to further beautify the forest landscape of Niushou Mountain and promote the healthy growth of the forests,the study attempts to put forward the targeted and operable functional zoning and construction layout scheme through the comprehensive ecological design method and 3S technology with its construction status and development needs.Based on the detailed investigation of forest landscape,resource quality and the NDVI analysis results of the study area,the study also tries to give the overall arrangement of each functional zoning at the small class scale,which provides practical experience for exploring the further integration of diverse culture and forest culture.

Design Practice on Fitness Greenway Landscape

LIU Wei

2021,(2):  45-51.  doi:10.13466/j.cnki.lyzygl.2021.02.007

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With the increasing demand for a healthy life among urban people in China,jogging and walking have become a popular exercise in cities.Thanks to the nationwide fitness campaign,urban residents have a new demand for open space in cities.This study takes Wangjing area of Beijing as an example and tries to adopt site survey and conduct research on public exercise and greenway construction at home and abroad,based on the public fitness demand.This paper puts forward the design scheme of fitness trail in this area,in order to provide reference for the planning and design of urban green ways in this area.

Calibration and Validation of National Forest and Grassland Inventory Airborne Large-Footprint LiDAR

LIU Yingchun, GAO Xianlian, HE Yan, CUI Chenyan, GAO Jianxin, YU Jiayong, CAI Longtao, WU Fayun

2021,(2):  52-60.  doi:10.13466/j.cnki.lyzygl.2021.02.008

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Forests play an important role in global terrestrial ecosystems.Precisely assessing forest resources and carbon sink with sample survey at a large scale is important before LiDAR is commonly used.To acquire precise geolocation of LiDAR footprint is an important step before it is applied in forest resource investigation because of the high special heterogeneity of forest height.In this paper,we use newly developed National Forest and Grassland Inventory Large-footprint LiDAR (NFGI-LIDAR-L)and ground Laser detector,develope a large-footprint LiDAR calibration method,improve the method of calculating the geocentric based on spatial pattern of laser from ground Laser detector,and calibrate NFGI-LIDAR-L.The results show that the method based on energy density of LiDAR improve the accuracy of calculating center location of large-footprint LiDAR from 5m to 1m.After calibration,the x,y,z and total accuracies of NFGI-LIDAR-L are improved from 60.51,52.76,1.88m and 80.30m to 0.61,0.54,0.05m and 0.82m,respectively.The absolute elevation accuracy of NFGI-LIDAR-L is 0.12m with flat surfaces validate with Ground Control Points.Therefore,the calibration method can be used in both calibration of airborne and spaceborne large-footprint LiDAR.

Research on Forest Biomass and Stock Volume Model Based on Stand Height and Canopy Density

WU Fayun, GAO Xianlian, ZHOU Rong, WANG Pengjie, FU Anmin

2021,(2):  61-67.  doi:10.13466/j.cnki.lyzygl.2021.02.009

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With the rapid development of LiDAR and stereo image space aerial remote sensing technology,although China has the ability to quickly obtain the information of average stand height and canopy density,there is a lack of models to accurately estimate the biomass and volume of forest,which seriously affects the popularization and application of the technologies.In order to explore the construction of the model,the average stand height,canopy density and plant number of 52 Chinese fir sample plots from the ground survey data in Xiangxi area of Central China's Hunan Province are used to construct several inversion models of Chinese fir aboveground biomass and volume in different function forms through different independent variables,and the model is evaluated by the coefficient of determination R².The results show that the combination of factor variables based on average stand height and canopy density is closely related to aboveground biomass and volume.Among them,the above ground biomass model and volume model of Chinese fir with e as the base logarithmic variable ln(C×HH²)as the explanatory variable have the best fitting effect;the exponential function model can accurately show the relationship between the independent variable and aboveground biomass and volume.Compared with the linear function model,power function model and logarithmic function model,the exponential function model has better fitting effect.Such methods prove effective to explore the relationship among average stand height,canopy density and aboveground biomass and volume of Chinese fir.The aboveground biomass model and volume model of Chinese fir are constructed in order to provide reference for establishing the aboveground biomass and volume model for other tree species estimated by average stand height and canopy density factors.

Sub-compartment Division and Basic Inventory Attributes Interpretation Based on Aero Digital Orthophoto Map in Sub-tropic Region

DAI Huabing, LI Chungan

2021,(2):  68-74.  doi:10.13466/j.cnki.lyzygl.2021.02.010

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Dividing sub-compartment and interpreting its basic inventory attributes indoors is the goal of forest resource investigators for a long time.In this paper,we study the characteristics of main tree species (group)in sub-tropic region on the aero digital orthophoto map,and then present a decision tree for aero image interpretation of tree species or tree species group.With the support of GIS software,the sub-compartment is divided by screen vectorization and the dominant tree species (group)is determined by visual interpretation.The result indicat that the average area error of sub-compartment is 0.5% and the spatial position overlap rate is 99.7%,which are significantly higher than the conventional method.The total positive precision of image interpretation for dominant tree species (group)is 97.5% and the kappa coefficient is 0.959 8.The paper confirm that the field work of sub-compartment division and basic inventory attributes investigation could be replaced mostly by the application of aero photography,which lays a solid foundation for accurate,rapid and efficient investigation and monitoring of forest resources.

Research on Growth Mixed Effect Model for Basal Area of Cunninghamia lanceolata Plantation Based on Site Factors

WU Xuping, LV Yong, ZHANG Xiongqing, YI Xuan, ZHU Guangyu

2021,(2):  75-82.  doi:10.13466/j.cnki.lyzygl.2021.02.011

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Based on data of 150 Cunninghamia lanceolata Plantation plots in Central China's Hunan Province,this study attempt to construct a mixed effect model of Cunninghamia lanceolata Plantation growth with site factors through using methods such as variance analysis,regression analysis,nonlinear mixed effects model and K-means clustering.The results show that:(1)Altitude (HB),slope (PD),slope position (PW),soil thickness (TH) and soil type (TL)have a significant impact on the growth of the basal area,and the order of significance is TL>TH>PD> PW>HB.(2)Among the eight commonly used theoretical growth equations,Schumacher (M5)has the highest coefficient of determination (R²=0.7636),and was selected as the basic model for forest basal area growth simulation.(3)A nonlinear mixed effects model was constructed by taking 107 site types (ST)of different site factor combinations as random effects and the coefficient of determination (R²)increased to 0.895 1.(4)The 107 site types (ST)were clustered into 5 site type groups (STG),and the mixed effect model of Cunninghamia lanceolata cross-sectional basal area growth was further constructed,and the determination coefficient (R²)increased to 0.920 2.Studies have shown that the nonlinear mixed effect model based on site factors objectively explains the impact of site factors on the growth of Cunninghamia lanceolata Plantation,which helps improve the simulation accuracy of the stand growth model.

Effects of the Cutting Intensity on Stand Growth and Structure for Querus mongolica Secondary Forests

DONG Lili, LIU Hongmin, WANG Chengcheng, YING Fangsheng, GAO Yingxu, DING Lei, LU Aijun

2021,(2):  83-91.  doi:10.13466/j.cnki.lyzygl.2021.02.012

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It is of great significance to study the changes of stand growth and stand structure under different cutting intensities for sustainable forest management.In this study,a natural secondary forest of 52 years old Quercus mongolica in mountainous area of eastern Liaoning was studied,and three fixed sample plots of high intensity (40%),medium intensity (29%)and control (0%)were set,respectively.Based on the long-term continuous observation data of 7 years in the after-cutting period,the effects of different cutting intensities on growth and stand structure were compared and analyzed.The results showed as follows:(1)cutting promoted the increase of mean DBH and individual volume.After 7 years of cutting,the average DBH of high intensity and medium intensity stands increased by 6.9cm and 5.2cm,respectively,and the individual volume was 1.8 times and 1.5 times than that of the control,respectively.(2)The cutting reduced the stand volume and increased the stand volume growth rate.The average annual growth rate of the stand volume during the 7-year period was medium intensity >high intensity >control.(3)The cutting reduces average value of mingling degree of stands,which makes the whole stand tend to be pure forest.In the spatial distribution pattern of stands,medium intensity increased the proportion of randomly distributed trees,and the whole stand distribution pattern showed randomly distribution;On the contrary,high intensity reduced the proportion of randomly distributed trees,and the whole stand distribution pattern showed aggregated distribution.Cutting promoted the growth of natural secondary forest of Quercus mongolica,optimized the stand structure,and medium intensity should be adopted.

Seed Germination Characteristics of Xanthoceras sorbifolia from 20 Provenances in Ordos Plateau

CAO Gongxiang, LIU Xinqian, JI Meng, WANG Zhibo, LV Meiping, ZHAO Fuzhou, XING Yukun, LI Yinxiang

2021,(2):  92-98.  doi:10.13466/j.cnki.lyzygl.2021.02.013

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Seed germination characteristics of Xanthoceras sorbifolia from 20 provenances were studied in Dalad Banner in this study in order to select excellent provenances that adapt to Ordos Plateau.The result showed that there were significant differences in the 100-seed weight among and within provenances of X.sorbifolia.The coefficient of variation within provenances ranged from 3.47% to 29.18%,and the coefficient of variation among provenances was 15.52%.The germination rate of seed from different provenances was above 80%.The germination potential ranged from 18.41% to 74.80%,and the coefficient of variation among provenances was 35.63%.The germination index ranged from 16.72 to 32.49,and the coefficient of variation among provenances was 18.24%.The germination speed ranged from 3.47 to 7.01 days,and the coefficient of variation among provenances was 20.74%.There were significant differences in seed germination rate,germination potential,germination index and germination speed among different provenances (P<0.001),which indicated that seed germination characteristics of different provenances of X.sorbifolia were obviously differentiated.The 20 species were divided into at least 3 groups by the clustering of the seed germination characteristics of the provenances,and five superior provenances were select preliminarily,including Bairin Left Banner (NTB),Kailu county(NTK),Hongshan District(NCH),Arhorqin Banner (NCK),and Jingbian County(SYJ).The findings provide scientific basis for the improved variety breeding and fine provenances selection of X.sorbifoli.

Estimation of Single Wood Factor of Picea schrenkiana var.tianshanica Forest Based on Backpack LiDAR

QIU Qin, ZHANG Wenge, WANG Lei, CAO Shanshan, SUN Wei

2021,(2):  99-109.  doi:10.13466/j.cnki.lyzygl.2021.02.014

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High precision lossless rapid estimation of single wood factor is very important for forest resource monitoring and evaluation.Backpack lidar has good application potential in obtaining 3D forest structure parameters.The study takes Picea schrenkiana var.tianshanica forest as the research object,trying to obtain the point cloud data by backpack LiDAR scanning sample for single wood segmentation and estimation of single wood DBH,tree height and crown area.The accuracy evaluation and correlation test are carried out with the reference of ground measurement and visual interpretation data.The results show that:the precision F values of single wood segmentation using backpack LiDAR data are greater than 0.90,the average accuracy and recall are 0.96 and 0.90,respectively.The average recognition rate is 86.61%.R² coefficient of determination of DBH and tree height is greater than 0.90,the average value of the DBH root mean square error is 1.11 and the height of the tree is 1.05;R² coefficient of determination for area estimation of single crown is greater than 0.80,the average value of the root mean square error is 3.21.Therefore,using backpack LiDAR can achieve high precision extraction of single wood DBH and tree height parameters.

Extraction of the Measuring Parameters of Pinus armandii Man-Made Forest Based on Visible Image of UAV

YUAN Zijian, SHU Qingtai, ZHAO Hongying, WANG Keren, TAN Dehong

2021,(2):  110-116.  doi:10.13466/j.cnki.lyzygl.2021.02.015

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Thanks to the portability of unmanned aerial vehicles (UAV)in monitoring of forest resources,this paper uses RGB tri-band image of UAV to extract the forest measuring parameters (number of stems,height of tree and stand volume)and perform precision validation.Taking P.armandii man-made forest as research object,RGB image of UAV as main information source and based on five individual-tree positioning of 0.08hm² P.armandii man-made forest sample plots in the early stage,this paper adopts canopy height model (CHM)maximum method and point cloud segmentation method to extract the measuring parameters of P.armandii and establishes a binary volume model of individual-tree in P.armandii man-made forest via RGB image of UAV.The results show that:(1)The results of individual-tree number and tree-height segmentation indicate that CHM maximum segmentation method has a higher precision than point cloud segmentation method,and the segmentation accuracy of the number of stems is 87.17% and 80.79%,respectively;the segmentation accuracy of the height of tree is 0.71 and 0.69,respectively.(2)The determination coefficient (R²)of the binary volume model established according to individual-tree crown breadth and tree-height extracted via CHM maximum method is 0.94,and its root-mean-square error (RMSE)is 0.033 8m³.The results are compared with those of the measured stock volume in standard land based on P.armandii of Yunnan Province binary volume table,the monitoring accuracy of stand volume of the five sample plots based on RGB data of UAV is 79.72%,81.64%,83.57%,82.49% and 80.28%,respectively,with the average accuracy reaching 81.54%.During the extraction of the measuring parameters of P.armandii man-made forest via RGB image of UAV,CHM maximum method is superior to point cloud segmentation method,and the binary volume model of tree height and crown breadth established by it can be used for UAV remote sensing in monitoring P.armandii monolayer man-made forest.

Research on Larch Extraction in Saihanba Mechanical Forest Farm Based on Sentinel-2 Data

LI Bin, LI Chonggui, LI Yu

2021,(2):  117-123.  doi:10.13466/j.cnki.lyzygl.2021.02.016

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As larch is the major part for forest management,the rapid and accurate extraction of the distribution of the larch plantation is of great significance to the operation and management of the Saihanba forest farm,which is a large State-owned forest farm in China.Remote sensing image classification based on traditional stand-alone mode is time-consuming and inefficient,while with the advance of geographic information big data and cloud computing era,Google Earth Engine (GEE),the pioneer of geospatial analysis platform,brings new opportunities for remote sensing image classification.The research is based on the GEE platform and uses Sentinel-2 data to realize the image classification of main tree species of the Saihanba Mechanical Forest Farm.By preprocessing the Sentinel-2 image data of 309 sceneries of the Saihanba Mechanical Forest Farm in 2019,the ratio vegetation index,texture features and topographic features are calculated,and the selection is optimized to construct a multi-feature classification data set.Then,the study compares the classification accuracy under the minimum distance method,decision tree and random forest classifier to obtain the tree species classification map of the forest farm with the best classification accuracy.The results show that the GEE has significant advantages compared with the single-machine image classification mode; the classification accuracy under the minimum distance,decision tree and random forest classifier are 80%,83% and 92%,respectively.Random forest classifier is more suitable for complex remote sensing classification tasks.

Research on Developing Stand Volume,Biomass and Carbon Stock Models for Major Forest Types in Beijing

YANG Xueyun, ZENG Weisheng, CHEN Xinyun

2021,(2):  124-130.  doi:10.13466/j.cnki.lyzygl.2021.02.017

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Stand-level volume,biomass and carbon stock models are quantitative tools for implementing forest resource management.Based on data of 1 425 permanent plots from forest inventory in 2016 in Beijing,and through approaches including independent nonlinear regression (INR),simultaneous error-in-variable equations (SEIVE),and SEIVE with dummy variable modeling,this study works out the stand-level volume,biomass and carbon stock models for ten major forest types,including Chinese pine (Pinus tabuliformis),cypress (Platycladus orientalis),oak (Quercus spp.),birch (Betula spp.),elm (Ulmus spp.),locust (Robinia pseudoacacia),poplar (Populus spp.),other hardwood broadleaved,other softwood broadleaved,and economic arboreal forest.The results show that the coefficients of determination (R²)of the stand-level volume,biomass and carbon stock models for 10 forest types are more than 0.93,the total relative errors (TREs)and average systematic errors (ASEs)are within ±3% and most of them are close to zero.The mean prediction errors (MPEs)are less than 5%,and the mean percent standard errors (MPSEs)are almost less than 15%.The following conclusions can be achieved that the volume stock per hectare of different forest types mainly depend upon basal area and average tree height of the forest stands,and the biomass stock mainly relate to volume stock and average tree height.The SEIVE with dummy variable modeling approach is a feasible method for developing stand-level stock models.The developed volume,biomass and carbon stock models for 10 forest types in Beijing in this study meet the need of precision requirements to the relevant regulation and can be applied on trial in practice.For improving the accuracy of the developed models,volume and biomass data of plot samples calculated by two-variable models need be used to further modify the models.

Evaluation of Red Edge of Sentinel-2A in Vegetation Classification of Lakeside Zone

PU Yihan, ZHANG Dong, XU Dandan, LUAN Zhaoqing

2021,(2):  131-139.  doi:10.13466/j.cnki.lyzygl.2021.02.018

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Sentinel-2A image has been widely used in the vegetation growth monitoring field thanks to the advantages of high spatial resolution and continuous times series.Its special settings of the red edge bands ensure it can accurately capture the vegetation red edge features,which can avoid the influence of chlorophyll saturation effect and make it possible for the vegetation classification of high vegetation coverage.This study makes the classification of vegetation community in the lakeside of Taihu lake based on existing knowledge and builds a vegetation red edge slope calculation model to calculate the variation of slope of red edge in 2017.Finally,the results of classification based on normalized vegetation index and quantitative statistics on the separability of different vegetation communities under different classification methods are used as verification.The results show that the slope of the red edge of vegetation has a better effect on the classification of vegetation community in the lakeside zone,and has a more obvious advantage in the period of high vegetation cover.Therefore,it can be concluded that the red edge slope feature of sentinel-2A has a good application in the classification of vegetation community.

Quality Evaluation of Mature Forest in Zunyi Based on Matter-Element Analysis

SUN Qian, JIANG Xinyan, ZOU Limei

2021,(2):  140-148.  doi:10.13466/j.cnki.lyzygl.2021.02.019

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To understand the quality of mature forest of Zunyi,Southwest China's Guizhou Province,this paper chooses data of the fourth forest resource planning and design survey in the province,tries to organize and analyze the small-class data of the city.It selects average DBH,average tree height,hectare volume,tree species structure,canopy density,comprehensive vegetation coverage,slope and soil layer thickness to establish the quality evaluation system,construct the matter-element model for forest quality evaluation and evaluate the forest quality of Zunyi for the first time.By summarizing and analyzing the results of quality evaluation,the study concludes that the area proportion of "poor,medium,good and excellent" grade of mature forest quality in Zunyi was 1.56%,45.72%,45.87% and 6.85%,respectively.Forest quality of Yuqing,Fenggang,Bozhou are relatively better among districts and counties as their mature forest area above medium level is as high as 60%.From the perspective of forest category,the quality of commercial forest is the best,followed by local public welfare forest.In general,the quality of mature forests in Zunyi is mainly in "medium" and "good" level,with only 6.85% of "excellent" level.The results show that there is a large space scope for the improvement of the quality of mature forest in Zunyi.Scientific and reasonable management measures can be formulated to improve the forest quality in the future management practice,so as to improve the forest quality.

Quantitative Dynamics and Spatial Distribution Pattern of Pinus yunnanensis Population in Northwest of Guizhou Province

HE Bin, LI Qing, LI Yangzheng, LI Wangjun

2021,(2):  149-157.  doi:10.13466/j.cnki.lyzygl.2021.02.020

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The study of population dynamics and spatial distribution pattern is of great significance to elucidate the population development mechanism,various ecological processes,as well as the stability and succession law of the community.This study aimed to clarify the structure of Pinus yunnanensis population in the northwest part of Guizhou Province.Through data from field survey and the method of “space instead of time”,the population dynamic quantitative characteristics are studied based on the static life table and quantitative analysis methods.The population distribution pattern was analyzed with the diffusion coefficient,aggregation intensity index and clumping index.The results showed that:(1)The population structure of P.yunnanensis was spindle type,and mainly aggregated on age classⅢ—ⅥⅠ(78.93%).(2)The population survival curves tended to be Deevey-Ⅱ type,indicating that the population was on an overall growth trend,but gradually tended to be stable.(3)The population distribution pattern was generally cluster distribution,but there were some differences in the degree of clustering of populations in different plots.With the increase of age class,the spatial distribution pattern of population changed from cluster distribution to uniform distribution.This study can provide theoretical basis for the sustainable management of Pinus yunnanensis forest and further provide reference for the management and protection of forest ecosystem in karst areas.

Short-Term Impact of Enclosure on Grass Layer and Soil in Larix principis-rupprechtii Plantations

XU Guoqiao, LI Xiao, WAN Yifeng, YANG Liu, XU Zhongqi, JIA Yanlong

2021,(2):  158-163.  doi:10.13466/j.cnki.lyzygl.2021.02.021

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To explore the effects of enclosure on soil and herbage in forest ecosystem,this paper studied the changes of herbaceous biomass,biodiversity,and soil physical properties in Larix principis-rupprechtii plantations in the north of Hebei province.The plots had been enclosed to avoid grazing for one year.The results showed that:(1)the herbaceous diversity index in the enclosed plots decreased slightly,but the dominance of vegetation in the communities changed significantly.(2)Compared with the control plots,the total biomass,aboveground biomass and underground biomass in the enclosed plots increased by 4.5,4.9,and 3.9 times,respectively.(3)The soil physical properties were changed by the enclosure.The soil bulk density in 0~20 cm decreased,while the soil porosity and water holding capacity increased.(4)The thickness and moisture content of litter layer increased.The study indicated that one-year enclosure can produce beneficial effects for soil and herbage in forest ecosystem.

Research on Tourism Image Perception of Yandang Mountain

LIN Xinying, LAI Pengcheng, CHEN Jianling, WU Yuanjing, HUANG Qitang

2021,(2):  164-170.  doi:10.13466/j.cnki.lyzygl.2021.02.022

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Scenic spots are China's representative characteristics in ecological system protection and have gradually become one of the important tourist destinations in recent years.This paper selects the Yandang Mountain scenic spot as the representative of Wenzhou nature reserve,tries to study the tourist reviews of seven major tourism websites,including Xiecheng,Qunaer and Meituan to study their tourism image perception based on content analysis and IPA analysis methods.The results show that:(1)The Erling and Yilong scenic spots in the Yandang Mountain Scenic Area are the most frequently mentioned words by tourists with a "core-sub core-peripheral" semantic network layout.(2)Positive emotions are mainly found in the tourists,and their neutral and negative emotions are under control.(3)Based on the perception of tourists,the tourism image of Yandang Mountain Scenic Area can be summarized into six major items:tourism resources,infrastructure,entertainment projects,service management,cultural experience,and emotional evaluation which can be subdivided into 16 elements for research.(4)The specific comments of the 16 constituent elements were sequentially coded and analyzed.The IPA model analysis was constructed to find that the performance scores of each element perceived by tourists are higher,but the importance scores are more scattered.Among them,natural landscape,public transportation,scenic spot management,and atmosphere evaluation are the advantage elements,and there are no weak elements.