Table of Content

28 April 2024, Issue 2

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Scientific Research

Characteristics and Influencing Factors of Soil Organic Carbon in Typical Vegetation in the Qilian Mountains

JIANG Shengxiu, ZHAO Peng, ZHANG Junnian, LI Delu, LIU Zixi

2024,(2):  1-7.  doi:10.13466/j.cnki.lczyyj.2024.02.001

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By exploring the spatial distribution characteristics and influencing factors of soil organic carbon in the typical vegetation of the Qilian Mountains,we aimed to provide a scientific basis for evaluating the carbon sequestration effects of forest soil in the region.Using converted cultivated land as a control,five typical vegetation types were studied:grassland,natural trees(Picea crassifolia,Sabina przewalskii),artificial trees(Larix gmelinii)and shrub.Soil organic carbon content,organic carbon density,soil grades,pH,electrical conductivity,total nitrogen,total potassium,and total phosphorus were measured at depths of 0-100 cm compare and analyze the distribution differences and main influencing factors of organic carbon components in different vegetation soils.Results showed:1)The average soil organic carbon content and organic carbon density under different vegetation types were as follows:P.crassifolia(5.99 g/kg,3.43 kg/m²,respectively)>S.przewalskii(5.59 g/kg,2.76 kg/m²,respectively)>L.gmelinii(2.91 g/kg,2.16 kg/m²,respectively)>shrub(1.83 g/kg,2.08 kg/m²,respectively)>grassland(1.66 g/kg,2.00 kg/m²,respectively)>abandoned lands(1.16 g/kg,1.33 kg/m²,respectively).2)With soil layer deepening,the overall organic carbon content of different vegetation soils tended to decrease,while the density of soil organic carbon showed a trend of first increasing and then decreasing.3)In the 0-100 cm soil layer,the soil C/N content of different vegetation types ranged from 9.30 to 15.73,with mean values as follows:P.crassifolia(14.96)>grassland(11.66)>abandoned land(11.54)>shrub(10.83)>L.gmelinii(10.69)>S.przewalskii(10.63).4)Organic carbon and total nitrogen content in different vegetation types showed a highly significant positive correlation(P<0.01),and a highly significant or significant positive correlation with total phosphorus,clay,and silt(P<0.01,P<0.05),a highly significant or significant negative correlation with sand content(P<0.01,P<0.05),and a significant negative correlation with pH(P<0.05).Thus the soil organic carbon retention capacity of natural trees in the Qilian Mountains is superior.Future carbon sequestration forestry construction should consider factors affecting soil organic carbon and prioritize dominant vegetation.

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

2024,(2):  8-16.  doi:10.13466/j.cnki.lczyyj.2024.02.002

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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.

The Spatial Distribution Pattern of Chunia bucklandioides in Jianfengling Area of Hainan Tropical Rainforest National Park

ZHANG Shunwei, LI Jinghan, YANG Xiaobo, LI Donghai, HUANG Yao, DU Chunyan, SHANG Naiyan

2024,(2):  17-25.  doi:10.13466/j.cnki.lczyyj.2024.02.003

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Chunia bucklandioides has been listed in key protected wild plants of national importance Class II,with a small population and narrow distribution.Studying the population characteristics and distribution of Chunia bucklandioides is of great significance for protecting the ecological environment and realizing the sustainable development of this species.The present research was conducted with Chunia bucklandioides in the Jianfengling area of Hainan Tropical Rainforest National Park.The diameter class was used to represent age class,and Chunia bucklandioides forest were divided into four age classes(I,II,III,IV).The pairwise correlation function g(r) was used to analyze the spatial distribution and correlation of different age classes of Chunia bucklandioides.The results showed that:1)The population of Chunia bucklandioides showed a pseudo-stable increasing trend,which could only survive but hard to expand its population size;2)The population of Chunia bucklandioides showed aggregated distribution at the small scale,and as the scale increased,the most of population developed into evenly distribution,while others showed random or aggregated;3)Individuals in different age classes were all aggregated at the small scale,and individuals in Class I and Class II showed a greater aggregation degree than others.As the scale increased,some age classes showed regular distribution and eventually evolved into random distribution;4)The germination and regeneration of Chunia bucklandioides mainly relied on individuals of Class III and Class IV,and the dependence of germinating individuals on the mother tree was Ⅱ>Ⅰ>Ⅲ>Ⅳ.Therefore,in the future,the main focus of conserving of the Chunia bucklandioides population should be on protecting the mother tree,appropriately intercutting budding seedlings around the mother tree and removing small plants near the budding seedlings of fallen branches.Additionally,live seedlings should be relocated for conservation as a means of expanding and conserving the wild population of Chunia bucklandioides.

Dynamics of Change in Age Group Structure of Arbor Forests in Zhejiang Province Based on Continuous Inventory Data

TANG Yanglong, LI Mengting, TAO Jixing

2024,(2):  26-33.  doi:10.13466/j.cnki.lczyyj.2024.02.004

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Based on the data from successive national forest resources inventories and annual monitoring of provincial forest resources in Zhejiang Province during 1979-2019,we analyzed the changes in the age group structure of arbor forests in Zhejiang Province over the past 40 years and predicted the development in the next 10 years by adopting methods such as statistical comparisons,analysis of the balance rate,and projections of area transfer.The results show that:1)During the 40 years,the changes in the age group structure of arbor forests in Zhejiang Province can be obviously divided into two phases.From 1979 to the end of the 20th century,there was a period of rapid growth in the area of arbor forests,and the age group equilibrium rate increased from 0.464 to 0.546,and the optimization of the age group structure was not the main successional feature;after entering the 21st century,the area of arbor forests was stagnant,and the age group equilibrium rate increased from 0.546 to 0.758,the optimization of age group structure has become the main successional feature;2)The age group structure of arbor forests in Zhejiang Province is now close to an ideal state,with the potential for forest resources to be fully cultivated,and it is predicted that it will reach an ideal state by 2029;3)At present,the arbor forests in Zhejiang Province have the problem of the overall age complementary effect of the stand,which means a relatively young age of one species and the relatively old age of another.It should be noted that the overall better age structure of the stand may mask the uneven age structure of individual species.Based on the current status of the age structure of arbor forests in Zhejiang Province and the target orientation of sustainable management,measures to optimize the age structure are proposed,with a view to promoting the improvement of the quality of forest resources and the capacity of carbon sequestration and sink enhancement.

Plant Water Use Efficiency of Different Intercropping Patterns in the Karst Area of the Lijiang River Watershed

TAO Wanglan, HUANG Fuzhao, LI Jianxing, WANG Zhiying, LUO Ting, LU Fang, LI Xiankun

2024,(2):  34-42.  doi:10.13466/j.cnki.lczyyj.2024.02.005

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Water is an essential factor limiting plant growth in Karst regions,so understanding the water relationships among different interspecific plants combinations in various intercropping patterns is important.To explore the plausibility of selecting of major non-woord tree species and medicinal plants,this study measured the stable carbon isotope composition of plant leaves in Prunus salicina-based on intercropping patterns and analyzed plant water use efficiency(WUE)to investigate the stability and plausibility of intercropping patterns.The results showed that the δ¹³C values and WUE of the six plantsleaves range from -31.6‰ to -28.7‰ and 20.56 to 37.94 μmol/mol,respectively.The rankings of δ¹³C and WUE were as follows:Illicium difengpi>P.salicina>Semiliquidambar cathayensis>Rubus chingii>Hypericum monogynum>Polygala fallax.It can be seen that I.difengpi,P.salicina,and S.cathayensis were more suitable for planting in Karst arid habitats,followed by R.chingii and H.monogynum,but P.fallax was not suitable for planting in such conditions.The WUE of P.salicina was significantly higher than that of the medicinal understory plants in the P.salicina+H.monogynum,P.salicina+P.fallax,and P.salicina+R.chingii,which exhibited significant differences in species fitness,indicated lower intercropping patterns stability.The P.salicina+S.cathayensis+I.difengpi had the highest WUE,and no significant differences in WUE were observed among the three tree species.This indicates their comparable fitness and stable coexistence.As a result,this intercropping patterns is considered an ideal model for agroforestry integration in the Karst region of the Lijiang River Watershed.

Spatial Distribution Patterns and Landscape Characteristics of Caragana korshinskii Groves in the Kubuqi Desert

AN Da, WANG Haibing, BAI Yunfei, LI Siqi, ZHANG Xue, XU Guangfu

2024,(2):  43-50.  doi:10.13466/j.cnki.lczyyj.2024.02.006

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Revealing the distribution and landscape characteristics of shrub resources in the Kubuqi Desert is of great significance to optimize the distribution structure of shrub resources in the region,increase the effectiveness of their protection and utilization,and solidify the effectiveness of sand control and prevention.Based on GF-2 remote sensing images,DEM,temperature,precipitation and other data,geospatial analysis techniques were used to analyze the distribution status and landscape characteristics of Caragana groves in the Kubuqi Desert.The results show that:1)the number of Caragana grove patches in the Kubuqi Desert is about 22 000,with a total area of about 21 000 hm²,accounting for 1.49% of the area of the Kubuqi Desert.Hangjin Banner has the most Caragana grove patches and Dongsheng District has the least;mobile sandy land has the most patches and saline land has the least.The patches are mostly distributed in the area of elevation 984-1 093 m,and the number of Caragana grove patches decreases with the increase of elevation;with the increase of temperature and precipitation,the number of patches increases,and the area with annual precipitation 309-356 mm is the most.2)The landscape pattern of different regions of the Kubuqi Desert is related to the terrain and geomorphology,temperature and precipitation,Caragana grove plantation type,and the desertification control effect.The northern region has low elevation,saline and alkaline land,belongs to the edge of Kubuqi Desert expansion,and is dominated by continuous sand prevention and sand blocking Caragana groves,the southern region has high elevation and low temperature,the main focus is on wind and sand control forests and soil and water conservation forests.,the western region has low elevation,flowing sandy land,arid climate,and belongs to desert grassland belt,and is dominated by natural dispersed Caragana groves,and the eastern region has good hydrothermal conditions,which is more distributed in areas of returning cultivated land to forests and on both sides of the roads.The Kubuqi Desert should strengthen the protection and restoration of Caragana groves in the western part of the desert,update the planting pattern of aged and degraded Caragana groves in the northern part of the desert in order to enhance its stability,and continue to increase the planting area of Caragana groves in the eastern part of the desert,where there are significant hydrothermal advantages,so as to supply sufficient forestry and grassland resources for Caragana grove industry development.

Plant Diversity in Mine Dumps and Its Coupling Relationship with Soil Physicochemical Indices

MA Yuan, ZHANG Jingbo, LIN Fangchun, XIN Zhiming, LUO Fengmin, YANG Yaoke, GUO Junting, WANG Jiapeng

2024,(2):  51-58.  doi:10.13466/j.cnki.lczyyj.2024.04.007

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To explore the coupling relationship between plant diversity and soil physicochemical indices in Manlailiang mining area,Ordos,under different restoration years,with the aim to reveal the interaction between vegetation and soil in ecological restoration,and to provide a scientific basis for optimizing vegetation restoration strategies and evaluating restoration effects.The physical and chemical indexes of vegetation and soil with restoration years ranging from 2 to 12 years were selected as the research objects.Vegetation and soil properties in different parts were investigated by comparing with the original landform,and the interaction and mode of action were revealed by correlation analysis.The results show that:1) A total of 51 species were surveyed in the study area,primarily consisting of Asteraceae,Gramineae and Fabaceae,which accounted for 61% of the total plants.2) Plant diversity exhibited significantly change over time,with the number of species first decreasing and then increasing,Margalef and Shannon-Weiner indices also follow this pattern,initially decreasing and then increasing.Pielou and Simpson indices,however,did not show significant change.3) Moderate to strong correlations were observed between plant diversity index and soil physicochemical index,particularly pH and total phosphorus,which had close correlated with plant diversity.4) During the initial stage of restoration,the coordination degree between plant diversity and soil physical and chemical indices increased,then decreased as restoration years increased,and subsequently increased again.The highest coordination degree was observed after 6 years of restoration.Repair measures have a positive effect on the balanced development of both aspect,but continuous maintenance and optimization are necessary to achieve the best coordination level.

Effect of Tending Cutting on Phosphorus Content in Mixed Forest of Vernicia montana and Phoebe bournei in Fujian Province

ZHENG Lingyu, LI Weihuang, XU Bingyan, WANG Yingzi, HONG Tao

2024,(2):  59-67.  doi:10.13466/j.cnki.lczyyj.2024.02.008

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The disturbance mechanism of phosphorus dynamic structure by tending cutting in the mixed forest of Vernicia montana and Phoebe bournei was clarified,providing a basis for the scientific management of soil phosphorus in this forest.Total phosphorus and available phosphorus content in soil and total phosphorus in branches,leaves,stems and roots of five year old Vernicia montana and Phoebe bournei from Fanqiao State-owned Forest Farm,Nanping,were determined.The impact of tending cutting on phosphorus content in rhizosphere soil and vegetative organs was studied.The results show that:1)Rhizosphere phosphorus enrichment was evident in both Vernicia montana and Phoebe bournei.Total phosphorus and available phosphorus levels in the rhizosphere soil were significantly higher than in non-rhizosphere soil before and after tending cutting(P<0.05).Tending cutting increased total phosphorus and available phosphorus in the rhizosphere soil(P<0.05).At a depth of 0-15 cm,rhizosphere soil phosphorus levels increased with depth for both species.2)Vernicia montana had higher total phosphorus and available phosphorus in rhizosphere soil at different soil depths compared to Phoebe bournei before and after tending cutting.After tending cutting,both total phosphorus content difference and available phosphorus content difference of rhizosphere soil increased at different soil depths of Vernicia montana and Phoebe bournei.The content of total phosphorus in branches,leaves,stems and roots of Vernicia montana and Phoebe bournei were increased by tending cutting.The content of total phosphorus in branches,leaves,stems and roots of Vernicia montana was higher than that of Phoebe bournei before and after tending cutting.3)Correlation analysis showed a significant positive correlation between available phosphorus in rhizosphere soil and total phosphorus in roots and leaves of Vernicia montana and Phoebe bournei(P<0.05),as wll as a significant positive correlation between total phosphorus in roots and total phosphorus in leaves(P<0.05).Tending cutting increased phosphorus content in vegetative organs and rhizosphere soil,with little effect on non-rhizosphere soil phosphorus.It promotes phosphorus activation and absorption in the rhizosphere soil of both.The effect of tending cutting on Vernicia montana was greater than on Phoebe bournei.The Vernicia montana root system is more developed than that of Phoebe bournei,granting it a stronger ability of soil phosphorus activation.

Volume Estimation Method of High Canopy Density Pinus massoniana Forest Based on UAV Image

LUO Yaopei, LI Heping, YANG Guangbin, CEN Gang, LI Man, CAO Qianyang, WANG Renru, CHEN Panfang

2024,(2):  68-79.  doi:10.13466/j.cnki.lczyyj.2024.02.009

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In order to reduce the cost of traditional field investigation and improve the efficiency of high canopy density forest resource investigation,multi-spectral UAV images combined with field sample survey data were used as the source data,and the Pinus massoniana pure stand was used as the research object.The stand stock volume in the study area was estimated by using the canopy height model(CHM)and six vegetation indices from multi-spectral images.The results show that:1)The assistance of a high-resolution digital elevation model can effectively compensate for the defect that UAV images can not extract ground points from in dense forests,improve the accuracy of CHM construction,and achieve accurate extraction of tree height in dense forests.2)When CHM was used to extract the tree height of a single tree in the study area and estimate the volume,292 Pinus massoniana were extracted from the plot,and the average tree height was 18.77 m.A total of 18 120 Pinus massoniana were extracted from the subcompartment area,and the average tree height was 17.02 m.The measured average tree height was 18.17 m.The average tree height extraction effect was good.The estimated volume was 7 466.74 m³,the measured volume was 9 024.40 m³,and the accuracy of the estimation was 82.90%.3)The RMSE of the vegetation index model is 0.39,R²=0.84,and the accuracy of the model is high.The volume is estimated to be 8 620.30 m³,and the estimation accuracy is 96.26%.By using UAV remote sensing technology,both of the two stock volume estimation methods can achieve rapid estimation of stock volume in high-canopy density forests.Among them,the effect of estimating stock volume by extracting vegetation index from multi-spectral data is better.This provides a strong scientific basis for further promotion and application of UAV images in surveys of forest resources with high canopy density.

Technical Application

Effect of Substrates and Exogenous Hormone on the Rooting of Air Layering of Berchemia floribunda(Wall.)Brongn.

ZHAO Tian, WANG Yinchen, ZHOU Sixuan, ZENG Bing, YUAN Yang, DENG Mengqing, LIAO Yan, ZHANG Jinhua

2024,(2):  80-91.  doi:10.13466/j.cnki.lczyyj.2024.02.010

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Berchemia floribunda(Wall.)Brongn.is a traditional precious tree species in China with functions as a nectar source,ornamental and medicinal source,and has good ecological and economic benefits.In order to optimize the optimal conditions for B.floribunda air layering propagation and to improve the vegetative propagation technology,the L₉(3⁴)orthogonal matrix experiment was performed to explore the effects of different substrate ratios,exogenous hormone types,exogenous hormone concentration and girdle width on rooting of its air layering,subordination function method and correlation analysis method were used to comprehensively evaluate various rooting indices,and the mechanism of these four factors on rooting explored.The results showed that a suitable substrate and exogenous hormone ratio can promote the formation of callus,along with an increase in various rooting indices.Variance analysis and range analysis indicated that the efficiency of air layering was affected by the substrate ratio,exogenous hormone and girdle width,substrates ratio and exogenous hormone types were the two most important factors.Based on a comprehensive evaluation and correlation analysis,it is concluded that the most favorable treatment condition for B.floribunda rooting is:perlite+peat+vermiculite(1∶1∶1)as substrates,NAA is used as an exogenous hormone types with a concentration of 400 mg/L,and the girdle width is 10 mm.Under this treatment,the callus induction rate is as high as (93.33±2.36)%,and the rooting rate is as high as(85.00±4.08)%,(9.67±0.47)days to form a callus at the wound site,(14.00±0.82)days start to take root,average number of first order roots[(15.44±0.51)roots],average length of first order roots[(7.13±0.25)cm],average diameter of first order roots[(3.03±0.21)mm],fresh weight[(3.29±0.05)g],dry weight[(0.67±0.04)g],root effect index(5.50±0.06),average subordinate function value(0.77)were the highest.The results of this study provide theoretical references and data support for establishing a rapid propagation system of B.floribunda and promoting its cultivation.

Individual Tree Segmentation Algorithm of Pinus MassonianaForest Based on Fusion Point Cloud Data

LI Wei, WANG Xiaohong

2024,(2):  92-100.  doi:10.13466/j.cnki.lczyyj.2024.02.011

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LiDAR technology has a great advantage in forest resources investigation,but the data collected by a single platform often has scanning blind spots,which makes it difficult to obtain complete forest structure information.For this reason,we take the Pinus massoniana forests as the research object and explore the suitability algorithm for individual tree segmentation of Pinus massoniana forests based on fusion point cloud data.We first proposed a method for fusing forest-sample point cloud data.Then,we adopted the marker-controlled watershed algorithm,distance-based clustering algorithm,and the layer stacking algorithm for the Pinus massoniana forests for individual tree segmentation.Finally,tree heights were extracted to verify the applicability of the fusion point cloud for estimating forest structural parameters.The experimental results are as follows:1)The proposed fusion point cloud method can effectively fuse airborne lidar point cloud and hand-held lidar point cloud with a registration error of 0.054 m.2)Among the three tree segmentation algorithms,the marker-controlled watershed algorithm has the highest segmentation accuracy,with an overall accuracy of 0.88,which is higher than the distance-based clustering algorithm and the layer stacking algorithm.3)The extracted tree height of individual tree segmented using the marker-controlled watershed algorithm has an R² of 0.983 7 and an RMSE of 0.759 6 m based on the fusion point cloud data,which is a significant improvement in accuracy compared to single point cloud data.The results of the study can provide technical support for the application of multi-source LiDAR in forestry field and the management of forest resources in Pinus massoniana forests.

Response of Net Photosynthetic Rate of Larix gmelinii to Physiological and Ecological Factors in Different Phenophases

GUAN Lei, ZHANG Xin, ZHANG Qiuliang, JIAN Ya’nan, ZHANG Yongliang

2024,(2):  101-108.  doi:10.13466/j.cnki.lczyyj.2024.02.012

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Studying the changes in the net photosynthetic rate(P_n) of Larix gmelinii in different phenophases and identifying its main influencing factors can help to elucidate the process and mechanism of carbon assimilation of Larix gmelinii.The LI-6400XT portable photosynthetic measurement system was used to measure the net photosynthetic rate,leaf temperature(T_leaf),stomatal conductance(G_S),intercellular CO₂ concentration(C_i),chlorophyll content(L_Chl),nitrogen content(L_N),photosynthetic active radiation(P_AR),air temperature(Ta),atmospheric CO₂ concentration(C_a) and vapor pressure deficit(VPD)of Larix gmelinii natural forest in the leaf opening period(LOP),leaf spreading period(LSP) and leaf discoloring period(LDP).Pearson correlation analysis and stepwise regression analysis were used to systematically study the variation characteristics of P_n in different phenophases of L.gmelinii and its relationship with physiological,ecological factors and material content.The results showed that:1) The order of P_n of Larix gmelinii was LSP>LDP>LOP,upper leaves>middle leaves>lower leaves,and the difference was significant;sun leaves>shade leaves,the difference was not significant.2) P_n was significantly or extremely significantly positively correlated with P_AR,T_a,T_leaf and G_S,and significantly or extremely significantly negatively correlated with C_i in different phenophases of L.gmelinii.3) The response of P_n of Larix gmelinii to physiological and ecological factors was dissimilar in different phenophases and at different canopy heights.The main control factors were P_AR,T_a and G_S.In addition,it was also affected by T_leaf,V_PD and C_i.There were significant differences in the net photosynthetic rate of L.gmelinii natural forest in different phenophases and at different canopy heights.When estimating carbon flux,the relative contribution of net photosynthetic rate of leaves at different canopy heights should be considered.

Health Assessment System of Forest Shelterbelts in Yulin Sandy Region of Mu Us Based on Analytic Hierarchy Process

QIAO Yi’na, CAO Shuangcheng, SHI Mengdi, DANG Hongzhong, QIN Yuqian, ZHAO Xiaobin, GAO Rong, SHI Changchun

2024,(2):  109-115.  doi:10.13466/j.cnki.lczyyj.2024.02.013

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It is significant for the scientific protection of forest shelterbelts and the formulation of sustainable management measures for forest shelterbelts.This can be achieved by researching and establishing health quality standards as well as assessment systems of forest shelterbelts,studying the health status of the forest area in the Yulin sandy region of Mu Us,and reasonably evaluating the health of the forest shelterbelts.Different types of forest shelterbelts in the Yulin sandy region of Mu Us were studied by using Analytic Hierarchy Process and Cluster Analysis to construct a health assessment system.The results show:1)The forest shelterbelt health assessment indicator system in Yulin sandy region of Mu Us is divided into 5 levels,including health(0.70~1.00),micro degradation(0.60~<0.70),mild degeneration(0.50~<0.60),moderate degradation(0.40~<0.50),Severe degradation(0~<0.40).2)According to analysis and assessment,the result shows the relatively bad health status of forest shelterbelts in the Yulin sandy region,which is belonged to the mild degeneration and moderate degradation.It is recommended to strengthen the management and protection of forest shelterbelts in the Yulin sandy region and reduce human and animal damage.This will achieve sustainable development and utilization of the forest shelterbelt in the Yulin sandy region of Mu Us.

Deffects of Biochar Application and Nitrogen Reduction on the Growth and Photosynthetic Characteristic of Phoebe bournei

YANG Ling, CHEN Zetao, CHEN Jiaxian, CHEN Zhufeng, ZENG Shucai, HE Qian, SU Yan, QIU Quan

2024,(2):  116-123.  doi:10.13466/j.cnki.lczyyj.2024.02.014

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In order to clarify the effects of biochar application and nitrogen reduction on the growth and photosynthetic characteristics of Phoebe bournei seedlings,four treatments were set up in a pot experiment,such as blank control(CK),conventional nitrogen application(F1),biochar application with 20% nitrogen reduction(F2B1)and biochar application with 40% nitrogen reduction(F3B2).After six months of treatment with F2B1 and F3B2,compared with CK,the results demonstrated that the plant height increased by 11.5% and 19.5%,respectively,and the ground diameter increased by 7.5% and 9.1%,respectively.The total leaf length of F1,F2B1 and F3B2 treatments was 10.1%,26.1% and 24.9% longer than that of CK,respectively.The same trend was observed for total leaf area,which was significantly higher than CK for all three fertilization treatments.However,there was no significant difference between the leaf shape coefficients.The results of photosynthetic physiological parameters revealed that the net photosynthetic rate(P_n),transpiration rate(T_r),and stomatal conductance(G_s) were markedly enhanced in F2B1 and F3B2 treatments compared to CK.There was no significant effect on water use efficiency.There was a significant positive association between plant height,ground diameter,and leaf net photosynthetic rate.Both F2B1 and F3B2 treatments could promote plant growth and photosynthesis.Among them the F3B2 treatment had better effects on plant height,net photosynthetic rate,and stomatal conductance.This study could serve as a framework for determining the ideal ratio of nitrogen fertilizer and biochar application when cultivating P.bournei seedlings.

Effects of Mixed Betula luminifera and Phyllostachys edulis with Different Proportions on the Growth of Cunninghamia lanceolata after Thinning

SUN Kun, WU Dayu, SUN Honggang

2024,(2):  124-132.  doi:10.13466/j.cnki.lczyyj.2024.02.015

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Scientifically reasonable mixed planting can restore soil fertility,enhance forest productivity,improve low-quality and low-efficiency forests,and achieve scientifically efficient management of Cunninghamia lanceolata plantations.By conducting forest thinning in Cunninghamia lanceolata plantations,mixed forests can be created with different proportions of Cunninghamia lanceolata and other species such as Betula luminifera or Phyllostachys edulis.This includes combinations with ratios of Cunninghamia lanceolata to Betula luminifera or Betula luminifera at 1∶1,2∶1,and 3∶1,respectively.The objective is to investigate the effects of mixed planting on the growth characteristics and functional traits of Cunninghamia lanceolata individuals.The results indicate that:1)Compared to pure forests,mixed planting increases the intensity of competition among trees.Additionally,the competition intensity between Cunninghamia lanceolata and Betula luminifera in mixed forests is lower than that between Cunninghamia lanceolata and Phyllostachys edulis.2)Mixed planting of Cunninghamia lanceolata with Betula luminifera and Phyllostachys edulis both increase the leaf area index(LAI)of Cunninghamia lanceolata.3)With the increase in Cunninghamia lanceolata retention density,the contents of available nitrogen,available phosphorus,and organic matter in the soil decrease.Compared to pure forests,mixed planting leads to a decrease of available nitrogen content in the soil but an increase in available phosphorus.4)As the retention density of Cunninghamia lanceolata increases,the individual tree volume of Cunninghamia lanceolata decreases,while the total stand volume increases in contrast.In Cunninghamia lanceolata mixed forests with Betula luminifera and Phyllostachys edulis,both the individual tree volume and the stand volume of Cunninghamia lanceolata are higher than those in pure forests of Cunninghamia lanceolata alone.In Cunninghamia lanceolata mixed forests with Betula luminifera,the individual tree volume and stand volume of Cunninghamia lanceolata are similarly greater than those in mixed forests with Phyllostachys edulis.5)The Hegyi competition index shows a highly significant negative correlation with the individual volume of Cunninghamia lanceolata(P<0.01);the individual volume of Cunninghamia lanceolata is significantly positively correlated with leaf area(P<0.05);available phosphorus is highly significantly positively correlated with individual volume and stand volume(P<0.01),and soil organic matter content is significantly positively correlated with stand volume(P<0.05).Based on the above findings,Cunninghamia lanceolata mixed forests with Betula luminifera are superior to those with Phyllostachys edulis in various aspects.Additionally,when the ratio of Cunninghamia lanceolata to Betula luminifera is 1∶1,it has the best promoting effect on the individual growth of Cunninghamia lanceolata,which is beneficial for cultivating large-diameter Cunninghamia lanceolata and improving stand quality.At the same time,attention should be paid to stand yield.When the ratio of Cunninghamia lanceolata to Betula luminifera is 3∶1,the stand volume of Cunninghamia lanceolata is maximized.

Research Briefing

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

2024,(2):  133-140.  doi:10.13466/j.cnki.lczyyj.2024.02.016

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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.

Classification of Urban Green Space in Yunnan Province Based on Sentinel-2A

XU Xiao, ZHANG Jialong

2024,(2):  141-148.  doi:10.13466/j.cnki.lczyyj.2024.02.017

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In order to understand the spatial distribution and composition of green spaces in major cities of Yunnan Province,the Wenshan,Jinghong,Mangshi,Shangri-La,and Yuxi are selected as the study areas.Based on Sentinel-2A satellite remote sensing images,features including spectrum,texture,vegetation index and terrain characteristics are extracted and.The random forest algorithm is used to classify the four types of green spaces:park green space,protective green space,affiliated green space,and production green space.The results show:1)Among the factors participating in the classification of four urban green spaces types,elevation exhibits the highest contribution.2)The mapping accuracy(PA)and user accuracy(UA)of green space classification in the five main urban areas surpass the accuracy of non-green space,with an overall accuracy(OA)and harmonic average F1 accuracy both exceeding 84%,and a Kappa value of 0.75.3)The classification accuracy of the four green spaces types in Jinghong City main urban area and Shangri-La main urban area is superior to that of Mangshi Main urban area,Wenshan main urban area and Yuxi main urban area.4)The total green space area in the five main urban areas of Wenshan,Jinghong,Mangshi,Shangri-La and Yuxi amounts to 6.22,20.81,2.52,6.65 and 8.58 km²,respectively.The random forest algorithm effectively classifies urban green spaces with high accuracy,thereby providing substantial technical support for green space resources planning and ecological environment protection management in Yunnan Province.

The Characteristics and High-Quality Development Strategies of the Pearl River Delta Forest City Agglomeration Construction

CHEN Han, YANG Kailiang, WANG Jie, QIN Lihou

2024,(2):  149-154.  doi:10.13466/j.cnki.lczyyj.2024.02.018

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The forest city agglomeration is a creative mode that has been explored during rapid ecological development of urbanization.The forest city agglomeration of the Pearl River Delta has a good construction base.However,it still has some issues,such as the fragmentation of ecological patches and weak greening between urban and rural areas.There is an urgent need for the region to mitigate ecological issues and improve ecological quality.Based on the background of national forest city agglomeration and forest city construction,this paper analyzes the development foundation and characteristics of forest city agglomeration in the Pearl River Delta.According to the characters of nine forest cities and regional ecological issues,the high-quality development strategy of forest city agglomeration in the region is discussed.Forest city agglomeration construction is an effective way to improve the ecological situation of a certain region.The construction of the Pearl River Delta forest city agglomeration is a case study for the movement and construction of other regional forest agglomerations.