Table of Content

28 June 2025, Issue 3

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Review

Research advances in space-air-ground integrated monitoring for smart forestry and grassland

XIE Ningbo, XU Xinqiao, WANG Qianpeng, CHEN Zhibo, YAN Ruihua, FENG Ge, ZHOU Qingyu, HUANG Yuxuan

2025,(3):  1-8.  doi:10.13466/j.cnki.lczyyj.2025.03.001

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Through the new generation of information technologies such as cloud computing,Internet of Things,mobile internet,big data and artificial intelligence,smart forestry and grassland can realize the comprehensive perception,accurate identification,dynamic monitoring,intelligent analysis and assistant decision-making of forestry and grassland resources and ecological environment.The high-quality development of smart forestry and grassland needs to be supported by high-quality monitoring data.In recent years,space-air-ground integrated monitoring technologies have been continuously innovated and developed,and monitoring capabilities have been continuously improved,which provide important opportunities for the development of smart forestry and grassland.In view of the integration of three monitoring paradigms:space-based monitoring,air-based monitoring,and ground-based monitoring,this paper focuses on the monitoring of forestry and grassland resources,wildfire monitoring,and pest and disease monitoring.We reviewedthe latest research progress of integrated space-air-ground monitoring technologies in the field of forestry and grassland in the world,and prospectsthe future research direction,expecting to provide a reference for smart forestry and grassland monitoring technology.

Research paper

Analysis of ecological environment change and driving factors of enclosure-conservation area for desertified land in Ningxia

GUO Liming, LIU Baojun, TIAN Naling, LI Qingbo, LI Wanying

2025,(3):  9-18.  doi:10.13466/j.cnki.lczyyj.2025.03.002

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Enclosure protection of desertified landis a management measure for desertified land,which curbs the process of desertification by restricting or prohibiting human activities.We used satellite remote sensing monitoring,aerial drone monitoring,ground sample survey and other means to monitor the ecological environment change of four national enclosure-conservation areas in Ningxia,and comprehensively evaluated the impact of closed protection on vegetation restoration and sandy land improvement through environmental factors analysis and land-use change analysis.The results show that:1)The average maximum NDVI value of the four enclosure-conservation areas of Yanchi Mechanized Forest Farm,Baijitan Sand Prevention Forest Farm in Lingwu City,Suanzaoliang in Hongsibu District and Changliushui in Shapotou District showed a positive growth trend.Compared with 2013,the average maximum NDVI value of the four enclosure-conservation areas in 2023 increased by 18.75%,29.16%,30.43% and 23.08%,respectively.2)From 2014 to 2023,in enclosure-conservation area,the degree of land desertification is reduced as a whole,and the area of mild and moderate desertified land is the largest.3)Total phosphorus,vegetation height,precipitation,sand cover thickness,desertification degree and organic matter are the key factors affecting the change of vegetation coverage.4)In each enclosure-conservation area,the influence of different types of environmental factors on vegetation coverage was ranked in descending order of sample factors,soil factors,meteorological factors,and topographic factors.In the future,desertified land management should be equipped with vegetation structures according to local conditions to achieve stable recovery and sustainable development of the ecosystem.

Spatial and temporal distribution characteristics of seed rain of relict plant Tetraena mongolica

YANG Yuewen, XING Yukun, LI Yinxiang, CAO Gongxiang, JI Yuanyuan, Sharentuya

2025,(3):  19-26.  doi:10.13466/j.cnki.lczyyj.2025.03.003

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Seed rain is a key link in the natural regeneration of plants.It is of great significance to study the spatial and temporal distribution characteristics of the seed rain of the relict plant Tetraena mongolica for revealing its endangered mechanism and resource protection and utilization.Taking the naturally distributed T.mongolica in the western Ordos area as the research object,the temporal and spatial dynamic characteristics of T.mongolica seed rain and its influencing factors were discussed by continuous observation of the seed scattering characteristics of T.mongolica from 2018 to 2020.The results showed that:1)The seed rain density of T.mongolica was significantly positively correlated with the precipitation in the growing season.The precipitation directly affected the seed setting rate and seed production,and then affected the seed rain density.2)The seed setting rate of T.mongolica was low,but its flower and fruit yield was high,which could ensure the seed production capacity of T.mongolica.The average seed rain density during the observation period was 305 seeds/m².The dispersal period of T.mongolica seed rain lasted from late August to early November,and the peak period of dispersal was in late September.The dispersal curve showed a ‘double peak’ type,which was consistent with the peak period of precipitation.3)The seed rain of T.mongolica was mainly concentrated in the interior and edge of the shrub,accounting for more than 85%,and the seed rain density decreased gradually with the increase of diffusion distance.The seed dispersal distance was 2.7 m at the farthest during the seed dropping period,and the dispersal ability was weak,which limited the expansion of T.mongolica population to new habitats to a certain extent,which may be one of the endangered factors.

Effects of different light intensities on the physiological characteristics of Alsophila spinulosa seedlings

LI Tengmin, RAO Dandan, CHEN Yu, HAN Yu, TIAN Mi

2025,(3):  27-37.  doi:10.13466/j.cnki.lczyyj.2025.03.004

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To investigate the effects of different light intensities on physiological characteristics of Alsophila spinulosa seedlings,a pot experiment was conducted under varying shading gradients to control light intensity.Seedlings were exposed to five treatments:Natural greenhouse light intensity(70% transmittance,CK),60% greenhouse light(T1),30% greenhouse light(T2),10% greenhouse light(T3),and 2% greenhouse light(T4).Parameters measured included leaf growth,photosynthetic pigments,antioxidant enzyme activities,membrane stability,and osmotic adjustment substances.The impacts of light intensity were analyzed using correlation analysis and fuzzy comprehensive evaluation.The results showed that:1)The aboveground biomass,underground biomass,and total biomass under T1-T4 treatments were significantly greater than those under CK treatment(P<0.05),while the root-shoot ratio(R/S)was significantly lower than that of CK treatments(P<0.05);2)Under T3 treatment,seedling growth was optimal,with leaf number,leaf length,and leaf width significantly greater than those under other treatments(P<0.05);3)Under T4 treatment,chlorophyll a(Chl a),chlorophyll b(Chl b),and total chlorophyll[Chl(a+b)]were significantly higher than those under other treatment(P<0.05),while carotenoid(Car)content was highest under the T3 treatment;4)As light intensity decreased,the activities of some antioxidant enzyme in the seedlings gradually increased,with superoxide dismutase(SOD)activity reaching its maximum under the T2 treatment;malondialdehyde(MDA)mass fraction,relative electrical conductivity(EC),and soluble sugar(SS)mass fraction gradually decreased,while soluble protein(SP)mass fraction gradually increased;5)Correlation analysis and fuzzy comprehensive evaluation indicated that A.spinulosa seedlings thrived under lower light conditions,with T3 treatment(10% greenhouse light intensity)identified as the optimal growth environment for them.These findings provide quantifiable key parameters for the population restoration of A.spinulosa,a Nationally Key Protected Wild Plant(Class II)in China-thereby enhancing its conservation success.

Effects of gibberellin(GA₃)on the changes of physiological activity substances during the germination process of the Aralia elata seeds in the Changbai Mountain region

FENG Bo, LI Chenglong, DAI Xinzhu, WANG Yuanyuan, CHEN Xingling, ZOU Jianjun, XU Guanghua, CHEN Dong

2025,(3):  38-44.  doi:10.13466/j.cnki.lczyyj.2025.03.005

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To investigate the effects of exogenous gibberellin(GA₃)solution on the variations of physiological activity substances during the germination process of Aralia elata seeds in the Changbai Mountain region,seeds of this region were soaked in GA₃ solutions at mass concentrations of 0(the control group),100,200,400 mg/L,and the variations of the mass fractions of soluble sugars,the mass fractions of soluble protein,the mass fractions of starch,as well as the amylase activities were analyzed during the seed germination process.The results indicated that during the germination process of Aralia elata seeds,the mass fractions of soluble sugars and starch,as well as the β-amylase activities overall exhibited a trend of initially increasing and then decreasing,while the α-amylase activities generally showed an opposite trend,initially decreasing and then increasing.Compared with the control group,appropriate mass concentrations of exogenous GA₃ solution could effectively facilitate seed germination of Aralia elata seeds in the Changbai Mountain region,and increased the mass fractions of soluble sugars,the mass fractions of soluble protein,and the β-amylase activities,while reduced the mass fractions of starch in the seeds after 20 days of stratification treatment.Notably,the treatment with the mass concentration of 400 mg/L GA₃ solution demonstrated the most significant effect.The promotion of exogenous GA₃ solution on seed germination was primarily achieved by promoting the hydrolysis of starch and enhancing the utilization of soluble sugars within the seeds,as well as currently inducing the synthesis of a series of crucial proteins during the seed germination process.

Effects of different vegetation restoration measures on soil physical properties in Hulun Buir Sandy Land

ZHU Lei, YUAN Limin, MENG Zhongju

2025,(3):  45-53.  doi:10.13466/j.cnki.lczyyj.2025.03.006

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In order to find out the effect of different plant restoration measures in Hulun Buir Sandy Land,grasp the difference of soil physical properties in different plant management areas,and provide reasonable suggestions for practical technology of sand management,five plant restoration measures of Corethrodendron fruticosum(UH),Caragana korshinskii(UC),Pinus sylvestris var. mongolica Litv.(UP),Corethrodendron fruticosum+Elymus dahuricus+Agropyron cristatum(HEA),Pinus sylvestris var.mongolica Litv+Corethrodendron fruticosum(HP)in Hulun Buir Sandy Land were taken as the research objects,and the mobile sandy land without any control measures was taken as the control(CK).The soil water content,bulk density and porosity in 0-100 cm soil layer of each region were measured,and the differences of soil physical properties in different regions were compared.The results showed that:1)The soil water content under UH,UC and HEA was relatively high,which increased by 121.90%,47.87% and 44.96%,respectively,compared with CK.The soil saturated water-holding capacity under UH、UC、UP、HEA、HP was significantly higher than that of CK(P<0.05),which increased by 27.48%,3.57%,5.44%,7.37% and 3.46%,respectively,and fluctuated with the increase of soil depth.2)Except for HP measure,the soil bulk density under the other four measures(UH,UC,UP,HEA)was significantly different from that of CK(P<0.05),which decreased by 5.42%,3.01%,2.41% and 1.81%,respectively,and decreased first and then increased with soil depth.3)The soil porosity under UH and UC measures increased by 3.48% and 2.47%,respectively,compared with CK,and there was no significant difference between other measures and CK.4)Through the comprehensive analysis of membership function,it was found that single shrub measures(UH,UC)and shrub-grass combination measures(HEA)had better overall recovery effect on the control area.

Soil seed bank dynamics in Pinus sylvestris var.mongholica pine forests in coal mining subsidence areas and their effects on vegetation restoration

DU Huadong, XUE Yimin, BI Yinli, TANG Xun, SUN Hao

2025,(3):  54-63.  doi:10.13466/j.cnki.lczyyj.2025.03.007

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Characterizing the composition and diversity of soil seed banks in artificial forests within coal mining subsidence areas,along with their effects on understory vegetation regeneration,provide a scientific foundation for the quality and efficiency management of plantation forests in coal mining subsidence land.Taking Pinus sylvestris var. mongholica forests with differentrestoration years(1-2,3-5,6-10 and 11-15 years)in the coal mining subsidence land in the Yushenfu mining area as the research subject,we characterized the evolutionary characteristics of soil seed bank density,composition,and diversity;deciphered the coupling relationships between the soil seed bank and aboveground vegetation;and investigated ecological drivers regulating soil seed bank features through monitoring edaphic factors,understory plant communities,and litter traits.The results showed that:1)The species composition of the soil seed bank shifted from being dominated by annual plants at 1-2 years of restoration to predominantly perennial plants after 11-15 years of recovery.2)The soil seed bank density peakedat 196 seeds/m² in years 3-5,but soil seed bank density progressively declined with the increasing stand age.The densities of Chenopodiaceae,Poaceae,Asteraceae,and Fabaceae plants reached their maximum values at 97 seeds/m² for 1-2 years,86 seeds/m² for 3-5 years,78 seeds/m² for 6-10 years,and 35 seeds/m² for 11-15 years,respectively.3)The species richness index of the soil seed bank initially increased then decreased with stand age,peaking at 6-10 years,while the Pielou evenness index and Shannon-Wiener diversity index exhibited no statistically significant changes.4)The species similarity between the understory soil seed bank and aboveground vegetation was the lowest in 1-2 years of restoration,with 9 common species of annual plants;the similarity reached a maximum value of 0.48 in 3-5 years of restoration,with a total of 12 species including both annual and biennualplants and perennial plants;and there were 11 and 10 common species in years of 6-10 and 11-15,respectively,dominated by perennialplants.5)Aboveground vegetation biomass,soil water content and total nitrogen were the common factors affecting understory soil seed density,diversity and similarity of aboveground vegetation and soil seed bank in different restoration years.In addition,soil capacity and aboveground vegetation cover in 1-2 years,aboveground vegetation density and soil organic matter in 3-5 years,litter layer thickness and cover in 6-10 years,and soil crust thickness in 11-15 years were also the heterogeneous main factors affecting understory soil seed banks in Pinus sylvestris var. mongholica forestry,the characteristics of the soil seed bank in the early succession stage of Pinus sylvestris var. mongholica forests were primarily influenced by aboveground vegetation and soil properties.As community succession progresses,the accumulation of understory litter and the formation of biological crusts exert increasing influence on the soil seed bank.In Pinus sylvestris var. mongholica forests of coal mining subsidence areas,both density and diversity of the soil seed bank decline after 10 years of succession,leading to reduced understory vegetation regeneration,seed bank supplementation and habitat optimization can effectively enhance understory vegetation recovery and improve its ecological functions.

Waterlogging tolerance of landscape plants in the Shisanling Reservoir downstream flood storage areas in Beijing

LU Tantan

2025,(3):  64-74.  doi:10.13466/j.cnki.lczyyj.2025.03.008

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The waterlogging tolerance in landscape plants serves as a critical selection criterion for optimized species screening in riparian landscaping.In the summer of 2023,a systematic field survey was conducted to assess the flood damage to 105 species(including cultivars)of landscape plants in the downstream flood storage areas,representing 39 families and 74 genera,following the controlled reservoir discharge from Shisanling Reservoir in Changping District,Beijing.The survey involved photographic documentation and written records of the growth vigor of the landscape plants.The waterlogging tolerance of the common landscape plant species in North China was stratified through comparative and inductive analysis.The results showed that:1)12 plants,such as Salix babylonica and Fraxinus chinensis,were most tolerant to waterlogging;2)13 plants,such as Diospyros kaki and Acer rubrum,were more tolerant to waterlogging;3)15 plants,such as Hibiscus grandiflorus and Iris lactea,were intermediately tolerant to waterlogging;4)15 plants,such as Pinus tabuliformis and Juniperus sabina,were less tolerant to waterlogging;5)50 plants,such as Helianthus annuus,Muhlenbergia capillaris,and Rhus typhina,were found to be least tolerant to waterlogging.Distinguishing the differences in waterlogging tolerance among plant species can provide a scientific basis and practical reference for the construction of waterfront parks and the selection of plant species in North China,as well as for landscape greening management.

Effect of tending management measures on the growth of near-mature forest stand of chinese fir

JIANG Yagui, WANG Ruihui, LIU Kaili, ZHANG Bin, JIAO Zenan, LIU Yuqian, ZOU Tao

2025,(3):  75-82.  doi:10.13466/j.cnki.lczyyj.2025.03.009

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Through tending management measures test with different thinning intensities and replanting in near-mature forest stands of Chinese fir,breaking through the requirements of the current technical regulations for forest tending,we studied the growth effect rule of different tending measures in near-mature Chinese fir forests,so as to optimize the stand structure transformation and promote full-cycle forest management and large diameter class timber cultivation of Chinese fir plantation forest.With a 21-year-old pure Chinese fir plantation as the research object,four treatments of 0%(CK),20%(T1),30%(T2)and 40%(T3)were set according to the thinning intensity on the basis of the number of trees combined with the replanting of broad-leaved tree species.Each treatment was repeated by three times to observe the growth of Chinese fir and replanted tree species under different treatments.The results indicate that,during five years after tending management measures,all of the average annual growth amounts of the DBH and tree height of Chinese fir,as well as the average annual growth amounts of individual tree volume and growing stock volume per unit area,show the order of T3>T2>T1>CK and the differences among the treatments are significant(P<0.05).Meanwhile,with the increase of the thinning intensity,the distribution curve of the number of trees in each diameter class of the Chinese fir forest stand shifted towards the larger diameter classes.For the replanted tree species including Ormosia henryi,Phoebe bournei,and Cyclobalanopsis glauca,the average ground diameter,average tree height,and the average annual growth amounts of ground diameter and tree height all show the order of T3>T2>T1>CK,and the differences among the treatments are significant(P<0.05).The growth of the nearly mature Chinese fir forest with high-intensity tending felling(felling intensity of 40%,retained density of 720 ind.hm²,and retained canopy density of 0.5)is the best.Among the three supplementary planted tree species,Ormosia henryi shows the best growth performance.

The mechanism of photosynthetic water niche differentiation between invasive species of Xanthium strumanum subsp.italicum and X.spinosum in the same domain

PANG Lidong, WU Baolong, CHEN Li, WANG Qi, PANG Wanlong

2025,(3):  83-91.  doi:10.13466/j.cnki.lczyyj.2025.03.010

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To elucidate the ecological mechanisms underlying the coexistence of two sympatric invasive species,Xanthium strumanum subsp.italicum and X.spinosum,through differentiation in photosynthetic-water utilization strategies,this study was conducted at Hailiu Reservoir in Inner Mongolia.The experimental design included establishing equidistant sampling plots from nearshore to offshore,encompassing monospecific stands(single-species dominant communities)and mixed communities.Leaf photosynthetic diurnal dynamics(net photosynthetic rate P_n,transpiration rate T_r,and stomatal conductance G_s)were measured using a Li-6800 photosynthesis system,and spatial autocorrelation analysis of soil water content was used to construct species distribution and water response curves.Key findings showed that:1)X. strumarium subsp. italicum exhibited a "bimodal" photosynthetic curve,with a maximum P_n of 47.91 μmol/(m²·s).This rate is 178.5% higher compared to that of X.spinosum[17.2 μmol/(m²·s)]and was associated with lower midday photoinhibition.In contrast,X.spinosum achieved a higher photosynthetic rate during morning hours,enabling it to seize an advantage in carbon assimilation early in the day.2)X.strumarium subsp. italicum dominated high-moisture habitats(>20.4%),while X.spinosum prevailed in arid zones(<12.7%),with coexistence occurring within a threshold interval of 14.8%-18.3%.3)X. strumarium subsp. italicum showed linearly increasing WUE with moisture(R²=0.83),indicative of water-conservative strategies,whereas X.spinosum displayed a WUE peak shift at a moisture level of 16.5%,regulated by stomatal oscillation.These results demonstrate that the two invaders achieve niche complementarity through "high photosynthetic efficiency/high transpiration" resource partitioning strategies,with their "photosynthetic-hydrological niche complementarity" mechanism providing a physiological basis for synergistic invasion.The findings offer critical insights for precision management of invasive plants in arid reservoir ecosystems.

Response of radial growth of Tsuga dumosa to climate change in northwestern Yunnan

KANG Yaoyao, YANG Yang, ZHOU Weicai, LI Lingyan

2025,(3):  92-99.  doi:10.13466/j.cnki.lczyyj.2025.03.011

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The growth dynamics of trees under the background of climate change have been a hot topic of ecological concern,therefore exploring the relationship between tree growth and climate is of great significance.In order to study the climate response laws of tree growth in northwest Yunnan Plateau,we selected Yulong Snow Mountain and Laojun Mountain as two typical areas,and studied the relationship between radial growth and climatic factors of Tsuga dumosa,by using the method of tree ring chronology.Two residual chronologies of T.dumosa were established by using data from tree ring widths and the spatiotemporal correlation between the annual ring index and climate factors was further analyzed.The results showed that T.dumosa growth was influenced by both precipitation and temperature.The radial growth of T.dumosa in Yulong Snow Mountain was significantly and positively correlated with the temperature in previous November and current June,and its growth was negatively and positively correlated with the precipitation in June and October of the current year,respectively.T.dumosa growth in Laojun Mountain was mainly affected by the water and heat conditions in May,showing a significantly negative correlation with temperature and a significantly positive correlation with precipitation,while showing a significantly positive correlation with temperature and precipitation in October.In the sliding analysis,the dynamic response of precipitation is more stable than temperature,confirming the decisive role of moisture conditions on an interannual scale.The growth of T.dumosa in Laojun Mountain presented the most significant correlations with precipitation of previous October and current May,while in Yulong Snow Mountain,significant correlations with precipitation of current June appeared in most years.The research results reveal the climate "memory effect" of the radial growth of T.dumosa on the late growing-season of the previous year,and the "immediate response" effect on the water and heat combination at the end of spring and beginning of summer in current year.

Quantitative classification and ordination of plant communities in the Liulianling Provincial Nature Reserve,Hainan

ZHOU Mengjun, CHEN Yingzhuan, PAN Liang, LIU Zichao, WU Can, ZHAN Caichi, DU Jiaqi, WEN Xuding

2025,(3):  100-108.  doi:10.13466/j.cnki.lczyyj.2025.03.012

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The Hainan Liulianling Provincial Nature Reserve(LPNR)was established in 1981,and mastering the classification and ordination of plant communities in the reserve is of great significance for plant protection and ecological management.To reveal the species composition of plants in the LPNR and the ecological relationships between plant communities and environmental factors,we conducted a numerical classification and ordination of the surveyed plant communities using two-way indicator species analysis(TWINSPAN classification)and canonical correspondence analysis(CCA two-dimensional ordination)with typical plot survey data and valid environmental data.This study analyzed the distribution patterns of plant communities in relation to environmental factors.The results indicated that:1)LPNR was mainly composed of tropical lowland secondary forests.A total of 211 plant species from 145 genera and 72 families were recorded in the survey plots,including 127 species in the tree layer,50 species in the shrub layer,and 34 species in the herb layer;2)According to the TWINSPAN classification method,the secondary forests within the reserve were divided into five communities,namely the Garcinia oblongifolia-Gironniera subaequalis-Calamus faberii+Schizostachyum hainanense,Garcinia oblongifolia+Ellipanthus glabrifolius,Engelhardia roxburghiana+Garcinia oblongifolia,Endospermum chinense+Gironniera subaequalis-Heptapleurum heptaphyllum+Microdesmis caseariifolia-Licuala hainanensis+Pandanus austrosinensis,and Heptapleurum heptaphyllum+Radermachera frondosa.All these communities were dominated by woody plants;3)The results of the CCA two-dimensional ordination showed that annual precipitation,annul mean temperature,and altitude were the main environmental factors influencing the distribution of plant communities in this area.Additionally,the biplot of t-values indicated that these significant environmental factors,such as annual precipitation,annul mean temperature,and altitude,had certain impacts on the dominant species in the tree plant communities.

Technical Application

Establishment and application of simultaneous models for estimating main stand characteristics based on Sentinel-2 data in Beijing

ZENG Weisheng, WEN Xuexiang, LI Xiaoyao, TAN Bingxiang, SUN Xiangnan, LIU Qiangyi, WANG Tian

2025,(3):  109-118.  doi:10.13466/j.cnki.lczyyj.2025.03.013

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In order to explore the feasibility of establishing main stand characteristics models based on Sentinel-2 data to estimate the factors of forest patches,the ground plot measured data and spectral characteristic metrics of 1 500 forest plots in Beijing were used to develop prediction models of three major forest types through the error-in-variable simultaneous equations.The models involve eight main stand characteristics,including mean DBH,mean height,dominant height,stem number,basal area,stock volume,biomass and carbon storage.Additionally,based on the spectral characteristic parameters extracted by 25 m×25 m grid cells within the forest patches in Beijing,the eight prediction models were used to estimate main stand characteristics of all forest patches.The results showed:1)The spectral characteristic metrics of Sentinel-2 that contributed the most to the estimation of main stand characteristics were B11 and B12(short wave infrared 1 and 2 band reflectance),followed by B5(red-edge 1 band reflectance)and RVI(Ratio Vegetation Index);2)The mean prediction errors(MPEs)of eight main stand characteristics models of three major forest types were less than 10%,either self-validation or cross-validation;3)The cumulative value of stock volume in all forest patches estimated by the volume models is only -1.74% lower than that obtained by the integrated monitoring of the municipality,which was within the allowable error range of sampling survey.The eight prediction models of three major forest types can be used to estimate the main stand characteristics of forest patches in Beijing;and the prediction accuracy of the main stand characteristics models based on spectral characteristic parameters of Sentinel-2 can almost meet the technical requirements of forest resource inventory and monitoring,then can be applied in practice.

Analysis of vegetation cover change and driving forces in Horqin Sandy Land using gridding

YU Shiyong, SUN Zhichao, CI Xuelun, YAN Jiahao

2025,(3):  119-126.  doi:10.13466/j.cnki.lczyyj.2025.03.014

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In the Horqin Sandy Land,as an ecologically fragile area in northern China,the change of vegetation cover is affected by both climate change and human activities.With the NDVI data,precipitation records,and remote sensing interpretation results of land use from 2000 to 2020,using models such as gridded analysis,correlation analysis,and the land use transfer matrix,we quantitatively evaluates the driving mechanism of precipitation and land use changes on vegetation cover.The results show that:1)The vegetation cover index in the study area shows an upward trend(with a growth rate of 0.007 5 a^-1),and spatially,it presents a pattern where the Xiliao River Basin in the southeast and central parts is high,the north and south sides are relatively low,and the southwest is the lowest;2)There is a positive correlation between precipitation and NDVI with the correlation coefficient of 0.74,and the precipitation shows a wave-like increase over time;3)In the change of land use,the area of farmland remains basically stable,the area of grasses increases slightly,the areas of water bodies and sandy wasteland decrease significantly,the construction area increases remarkably,and the area of forest land accounts for the smallest proportion but has the largest growth rate;4)Among all land use types in 2020,the NDVI value of farmland is the largest,and that of sandy wasteland is the smallest.

Health assessment of Robinia pseudoacacia plantations in the Henan Old Yellow River Course area using PLS-SEM Model

YE Peixia, LUO Kai, SHEN Zhenhai, JIN Shanshan, ZHOU Mengli, YAN Dongfeng

2025,(3):  127-138.  doi:10.13466/j.cnki.lczyyj.2025.03.015

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The Robinia pseudoacacia plantations in the sandy areas of the Yellow River floodplain in Henan Province exhibit a widespread degradation trend,significantly impacting the regional ecological environment.Accurately and scientifically evaluating their health status is critical for the restoration of degraded forests.This study focused on the R.pseudoacacia plantations in Zhongmu Forest Farm,located in the Yellow River floodplain of Henan Province.With field investigationsconductedin 44 representative plots,22 indicators across four dimensions involving stand productivity,stand site,stand resistance and stand structure were selected.Using Partial Least Squares Structural Equation Modeling(PLS-SEM),K-means clustering analysis,and Fisher discriminant analysis,a health assessment system and a health index model suitable for this region were established,followed by a comprehensive evaluation of stand health status.The results showed that the constructed PLS-SEM passed tests of validity,model fit,and significance.By using the PLS-SEMmodel,the weights of the four latent variable layersof stand productivity,stand site,stand resistance,and stand structure,were determined as 0.257,0.233,0.256,and 0.254,respectively.The health evaluation index of the studied R.pseudoacacia plantations ranged from 2.266 to 3.272.Among them,11.4% were in a healthy state,25.0% in a sub-healthy state,45.4% in a moderately healthy state,and 18.2% in an unhealthy state.The comprehensive findings indicate that stand productivity and stand resistance are the key dimensions determining the health of R.pseudoacacia plantations in the Henan Yellow River Old Course area.Specifically,mean tree height was identified as the most critical indicator of stand productivity,while external disturbance emerged as the primary constraining factor for stand resistance.