Table of Content

28 August 2024, Issue 4

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Integrated Management and Administration

Carbon Emissions and Carbon Sequestration Capacity in Chinese Provinces from 1997 to 2021

ZHANG Yuxing, ZHANG Zhe, YIN Jingping, PU Ying

2024,(4):  1-11.  doi:10.13466/j.cnki.lczyyj.2024.04.001

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This study conducts an analysis of carbon emissions and the carbon sequestration capacity of forest vegetation across 30 provinces(excluding Hong Kong,Macao,Taiwan,and Xizang)in China from 1997 to 2021.1)Most provinces are still experiencing an increasing trend in carbon emissions,with only 8 provinces nearing or achieving the carbon peak goal by 2021.2)China has initially achieved preliminary success in carbon emission reduction,with technological advancements playing a significant role.Carbon intensity has shown a year-on-year decline,with 18 provinces reducing their carbon intensity by more than 65% compared to 2005,typically in economically advanced regions.3)There is a significant correlation between carbon emissions and GDP.In 2021,the five provinces with the lowest carbon intensity accounted for only 5.11% of national carbon emissions but contributed 16.25% to the national GDP,whereas the 5 provinces with the highest carbon intensity contributed 33.51% to national carbon emissions but only 6.98% to the national GDP.4)As for 2021,energy consumption in China is still dominated by coal and petroleum,accounting for 91% of energy consumption.The impact of the incremental energy consumption on GDP growth exhibits a lag effect;however,as the economic output efficiency per unit of energy consumption significantly improves,such lag effect is gradually diminishing.5)The annual carbon fixation ability of national forest vegetation has continuously increased.In 2021,the national forest carbon sink reached 451 million tons,absorbing the equivalent of 1.655 billion tons of CO₂,with an annual average increase rate of 4.02% from 2017 to 2021.However,it is significantly lower than the annual average growth rate of carbon emissions,which is at 10.7%.6)The carbon sequestration capacity of forests in each province has improved,yet for most provinces,forest carbon sequestration accounts for less than 10% of their annual emissions.Jiangxi,Guangxi,Jilin,and Hunan exceed 30%;Yunnan and Sichuan are notably efficient,with their forest carbon sequestration are 2.16 times and 1.13 times of their carbon emissions.7)In 2021,the carbon sequestration of forest vegetation accounted for 12.63% of the carbon emissions of that year in China,and the terrestrial ecosystems accounted for 23% of the annual emissions.Although the growth rate of carbon emissions continues to exceed that of the carbon absorption capacity of forest vegetation,terrestrial ecosystems,primarily forest ecosystems,remain crucial for achieving carbon neutrality in China.Protecting and enhancing the productivity of forest ecosystems is crucial for further increasing carbon sink capacity and achieving carbon neutrality goal after the carbon reduction potential approaches its limit.

Advances in Research on Plant Carbon Sequestration Capacity Across Different Vegetation Zones in China

LIU Tong, BAO Shouchen, YUAN Tao

2024,(4):  12-20.  doi:10.13466/j.cnki.lczyyj.2024.04.002

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Plants serve as the primary carbon sink carriers in terrestrial ecosystems and are of great significance for maintaining ecological balance.Systematic analysis of the measurement methods of the whole plant carbon sink(plot inventory method,assimilation method,remote sensing estimation method,microclimate method)and its advantages and disadvantages,as well as scope of application.Using the widely adopted assimilation method,compared and analyzed the carbon sink capacity of plants in six vegetation zonesin China,considering plant growth forms,ecological habits,and environmental factors.The results revealedsignificant variations in the carbon sink capacity of plants across different vegetation zones.In the temperate coniferous broad-leaved mixed forest area and the warm temperate deciduous broad-leaved forest zones,trees exhibited slightly higher carbon sink capacities than shrubs.Conversely,in the tropical monsoon rain forest and temperate grassland zones,shrubs demonstrated significantly higher carbon sink capacities than trees.In addition,there are significant differences in carbon sink capacity between coniferous and broadleaved trees.Aquatic and ground cover plants exhibit substantial potential for carbon sink,and have the possibility of further development.The study also indicated that carbon sink measurement methods and environmental factors significantly influence the evaluation ofplant carbon sink capacity.Based on the findings,it is recommended to establish a unified evaluation standard for carbon sink capacity,broadenthe scope of plant species and research coverage,and develop a more comprehensive framework for evaluating and enhancing carbon sink capacities across vegetation zones.Such efforts canprovide scientific guidance for ecological restoration,landscape tree species selection,andachieving carbon neutrality targets.

Scientific Research

Development of Forest Volume Model Based on Nonlinear Mixed-effect for Cunninghamia lanceolata

DU Zhi, CHEN Zhenxiong, HE Dongbei, LIU Ziwei, HUANG Xin

2024,(4):  21-28.  doi:10.13466/j.cnki.lczyyj.2024.04.003

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The nonlinear mixed-effect model of Cunninghamia lanceolata forest volume was developed using easily accessible stand characteristic factors,site,and climate factors obtained from field investigation.This model provides technical support for forest volume monitoring by UAV LiDAR technology.Based on mensuration data from 580 sample plots of Cunninghamia lanceolata forest and comprehensive ecological monitoring of grassland in Hunan Province and Guangxi Zhuang Autonomous Region between 2021 and 2023,a basic model for stand volume,including stand characteristic factors,was constructed.Subsequently,a nonlinear mixed-effects model was developed by incorporating site and climate factors,and determining both fixed and random effect variables.The models were evaluated using 10-fold cross-validation.The results revealed that stand characteristic factors(such as average dominant height and canopy density),site factors(elevation),and climate factors(annual mean temperature)were strongly correlated with the hectare volume of stand.The basic stand volume model,based on average dominant height,canopy density and age group,was constructed.Compared to the basic model,the nonlinear mixed-effect model,which included altitude as a fixed effect and the annual mean temperature difference among plots as a random effect,showed improved fitting accuracy.The determination coefficient(R²)increased from 0.616 to 0.654,while the standard error of the estimate(E_SE),mean prediction error(E_MP),and mean percent standard errors(E_MPS)were reduced.The relationship between stand volume and factors such as average dominant height,canopy density,site and climate factors are effectively explored.The resulting stand volume model demonstrates practical applicability,and all the variables used in modeling could be derived from UAV LiDAR point cloud data or coordinate information,providing a valuable reference for regional forest volume monitoring using LiDAR technology.

Competitive Relationship between Dominant Populations of Karst Secondary Forests

XU Ming, CHAI Zongzheng, SUN Caili, WANG Hua

2024,(4):  29-38.  doi:10.13466/j.cnki.lczyyj.2024.04.004

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This study explored the competitive relationships among dominant populations in secondary forests in karst areas.A typical karst secondary forest in the Zhongdong Scenic Spot of the Getu National Scenic Areas in Ziyun Miao and Buyi Autonomous County,Guizhou Province,abandoned for over 30 years,was selected as the study area.Based on 1.68 hm² fixed sample plots,the Hegyi Competition Index was used to quantitatively analyze competitive relationships through field surveys.1)Based on the number of plants,a total of 2 805 trees with a diameter at breast height(D_BH)more than 1 cm was investigated.Among these,the species consisting of Betula luminifera,Platycarya strobilacea,Pinus massoniana,Liquidambar formosana,and Populus davidiana collectively account for 2 455 individuals,constituting 87.52% of the total number of plants,and are thus identified as the dominant populations.2)The competitive pressure among trees was mainly exerted by those within 5 meters.However,for Betula luminifera and Liquidambar formosana,interspecific competition exceeded the intraspecific competition.The other three populations had more intraspecific than interspecific competition,which indicated that the competitive pressure of the secondary forests was mainly dominated by intraspecific competition.The intraspecific competitive pressures of the five dominant populations were ranked as follows:Platycarya strobilacea>Populus davidiana>Pinus massoniana>Liquidambar formosana>Betula luminifera.3)Competition model predictions showed a power function relationship between D_BH and competition intensity in dominant populations,revealing that competition intensity tended to weaken with the gradual increase in D_BH of individual trees in the population.The competition was most intense when D_BH of individual trees in the population stands was in the range of 3 to 5 cm.After D_BH reached 10 cm,the change in competition intensity tended to stabilize.Timely nursery management is recommended to reduce competitive pressure and enhance the stability before the D_BH reaches 10 cm.

Effects of Forest Types at Different Altitudes on Soil Hydrological Functions in Huoditang,Qinling Mountains

ZHANG Shulan, ZHANG Haijun, ZHANG Yihao, WU Xiaoyu

2024,(4):  39-47.  doi:10.13466/j.cnki.lczyyj.2024.04.005

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The study of forest soil hydrology functions and their influencing factors is of great significance for regional forest water conservation and ecological evaluation of soil and water conservation.Soil samples were collected from seven typical forest types at different elevations in Huoditang,Qinling Mountains.The soil physical and chemical properties,water retention characteristics,macropore and saturated hydraulic conductivity from different forest types were determined by the ring knife method,potassium dichromate oxidation method,screening method and fixed water head method.The hydrological function indices were then statistically analyzed.1)Soil water holding capacity of all forest types decreases with the increasing soil depth,and the field water holding capacity ranges from 29.95% to 76.66%.The soil water holding capacity of the Picea wilsonii forest,Abies fabri forest,Tsuga chinensis forest and Larix gmelinii var.principis-rupprechtii forest located at a higher altitude(>1 900 m)is greater than that of Pinus tabuliformis forest,Larix kaempferi forest and Quercus aliena var.acuteserrata forest at low altitude(from 1 400 to 1 700 m)was lower.Conversely,the water holding capacity of higher altitude forest types(except Tsuga chinensis forest,which has the largest water storage capacity)is lower,while that of lower altitude forest types is higher.2)The saturated hydraulic conductivity of the soil layer of different forest types ranges from 0.02 to 9.82 mm/min.The average saturated hydraulic conductivity is as follows:Quercus aliena var.acuteserrata forest>Tsuga chinensis forest>Larix kaempferi forest>Picea wilsonii forest>Pinus tabuliformis forest>Larix gmelinii var.principis-rupprechtii forest>Abies fabri forest.3)Forest soil water holding capacity was significantly correlated with soil bulk density,total porosity,and organic matter content.Soil saturated hydraulic conductivity was significantly correlated with soil macropore,gravel content,silt and clay content.Moreover,forest soil saturated hydraulic conductivity was significantly positively correlated with the number of macropore.

Analysis of Soil Heat Flux Characteristics and Influencing Factors in Cenchrus fungigraminus Grasslands in the Northwest Semi-arid Region

WANG Ziyi, LYU Shi, LI Shengfan, BAI Nini, YAN Huihui, LIN Hui, YU Shikui, LIU Fengshan

2024,(4):  48-59.  doi:10.13466/j.cnki.lczyyj.2024.04.006

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Soil heat flux is a key index of energy exchange within the Earth system,exerting important influences on meteorology,ecosystem,groundwater cycle and agricultural production.This study examines the Cenchrus fungigraminus ecosystem in the semi-arid region of northwest China,calculating soil heat flux was calculated by the heat conduction convection method,employing the observational data of the Bowen ratio system in 2022.The characteristics and influencing factors of energy balance were analyzed.1)During the planting period,Cenchrus fungigraminus significantly reduced soil energy loss,and enhanced the correlation between soil heat flux and surface at the depths of 10 cm and 20 cm.Surface soil volumetric heat capacity exceeded the annual average during the planting period escalated with depth.2)Before planting,the soil heat flux at 20 cm depth was similar to that at the surface,but the peak value was higher and there was a lag phenomenon.During the harvest period,the soil heat flux at the depth of 10 cm and 20 cm was higher than the surface,and the whole was negative,indicating that the soil transferred energy to the atmosphere.3)On sunny days,peak surface soil heat flux values surpassed those on cloudy and rainy days,with varying times of occurrence.During the planting period,the fluctuation of soil heat flux in sunny and rainy days was small,but the heat flux in sunny days was lower than that in rainy days.The fluctuation of heat flux on sunny days increases with increasing depth.4)During the planting period,the height and soil moisture were the main factors affecting soil heat flux.Before and after planting,solar radiation,air temperature,soil temperature and air humidity were the main influencing factors.There was no significant correlation between precipitation and soil heat flux before and after planting,but there was a significant negative correlation between precipitation and soil heat flux during the planting period.In summary,coverage by Cenchrus fungigraminus can facilitate reduction in soil energy loss,augment soil volumetric heat capacity,and stabilize fluctuations in soil heat flux.

Construction and Optimization of Ecological Network in the Core Area of Changsha-Zhuzhou-Xiangtan Based on MSPA-Linkage Mapper

SHE Yuchen, CHEN Chulin, MAO Shuzhen, TAN Juan

2024,(4):  60-69.  doi:10.13466/j.cnki.lczyyj.2024.04.007

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Rapid urbanization has led to landscape fragmentation and increased ecological risks.Constructing and optimizing ecological networks is crucial strategies for ensuring regional ecological security and sustaining ecosystem services.This study focuses on the core area of Changsha-Zhuzhou-Xiangtan urban agglomeration,using morphological spatial pattern analysis(MSPA),remote sensing ecological index(RSEI),and landscape connectivity analysis to comprehensively identify ecological source areas.Considering factors such as terrain,topography,landscape types,and human interference,and utilizing the entropy method to establish a combined resistance surface,the utilizing the entropy method to establish a combined resistance surface,the study employed Linkage Mapper to develop an ecological network,incorporating stepping stone patches and ecological corridors to enhance network structure.Subsequently,the structural indices of the optimized ecological network were compared before and after optimization.1)Seven distinct landscape types were identified through MSPA,with the core area boasts the largest expanse.2)Core ecological source areas are primarily located in the northeastern and southern regions of the study area,whereas middle and western regions exhibit relative sparsity with uneven distribution and poor connectivity.3)Affected by human activities in the central urban area,overall resistance within the study area is characterized by high levels in central locations,which decrease towards peripheral zones.4)A total of 59 ecological corridors were identified,predominantly concentrated around high-quality patches in the northeastern and southern areas,while lateral connectivity remains inadequate in the eastern and western sections.5)The addition of seven stepping stone patches and nineteen new ecological corridors led to significant improvements in both the structural indices of the optimized network and its stability.The optimized ecological network structure has achieved significant improvements in both connectivity and stability.These improvements underscore that optimization measures have effectively enhanced landscape connectivity and ecosystem restoration capabilities in this region,while potentially mitigating environmental issues caused by rapid urban development within the Changsha-Zhuzhou-Xiangtan urban agglomeration.

Analysis of Changes in Land Use Landscape Pattern in Wenchuan County

ZENG Shuangbei, ZHANG Dawei, DU Zongyi

2024,(4):  70-77.  doi:10.13466/j.cnki.lczyyj.2024.04.008

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The use of Geographic Information Systems and remote sensing technology to analyze the spatiotemporal changes in regional land use landscape patterns provide technical support for understanding ecological environmental changes and ecosystem stability.Taking Wenchuan County,Sichuan Province as the research area,the spatiotemporal evolution of land use patterns is analyzed using the comprehensive land use index and landscape ecological index methods.1)From 2007 to 2020,the total areas of cultivated land and forest land in Wenchuan County decreased,while the area of construction land increased.2)The comprehensive land use index in Wenchuan County showed an increasing trend.Between 2007 and 2014,the land use index in towns and villages in the northeastern and southeastern parts of Wenchuan County rebounded rapidly.From 2014 to 2020,the land use index in the western towns of Wenchuan County underwent significant changes.Through a combination of artificial measures and natural restoration,vegetation recovery improved and the land use structure became increasingly reasonable.3)From 2007 to 2020,the patch density and landscape shape index in Wenchuan County initially increased,then decreased,while the aggregation index showed an initial decrease followed by an increase.These trends indicate that the earthquakes initially intensified landscape fragmentation,increased heterogeneity,reduced connectivity between landscape patches,and significantly degraded the ecological environment.However,driven by factors such as post-disaster reconstruction and ecological protection and restoration,the impact of earthquakes and other disasters gradually weakened.As a result,landscape fragmentation decreased,landscape heterogeneity reduced,and landscape shape and connectivity between patches returned to pre-earthquake levels.The regional ecological environment gradually improved.

Fitting Methods of Mutual Dependent Variable Models in Forestry

ZENG Weisheng

2024,(4):  78-83.  doi:10.13466/j.cnki.lczyyj.2024.04.009

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The dual regression method can be used to fit the mutual dependent variable models,however,the error structure relationship between the two variables must be provided in application,and this method is only applicable to the linear error-in-variable model in ForStat,which brings inconvenience to forestry modeling.Using the measured data of dominant height(H₀),mean height(H)and mean diameter at breast height(D)from 100 sample plots in Pinus koraiensis forests in northeastern China,this paper demonstrates two regression lines in fitting the H₀-H model and the H-D model.Two new methods are proposed by introducing dummy variables to distinguish two regression lines,followed by the use of nonlinear simultaneous equations with error-in-variables or multivariate nonlinear regression estimation method to estimate the parameters of mutual dependent variable models.These new methods are applicable not only to common linear models such as the H₀-H model,but also to nonlinear models such as the H-D model.

Response of Tetraena mongolica Plant Communit to Varying Grazing Intensities

JI Yufei, YANG Yongzhi, PANG Lidong, JIA Fangbin, LU Xueyan, GAO Runhong

2024,(4):  84-93.  doi:10.13466/j.cnki.lczyyj.2024.04.010

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This study focused on the Tetraena mongolica plant community,examining the effects of different grazing intensities light grazing(LG),moderate grazing(MG),heavy grazing(HG)and no grazing(NG)as the control,onplant species composition,species diversity,biomass,and population regeneration.1)As grazing intensity increased,the importance value of dominant species Tetraena mongolica in the community showed an upward trend.HG reduced the importance values of Cleistogenes songorica and Eragrostis pilosa in the herbaceous community,while increasing the importance values of Allium mongolicum and Peganum harmala.2)Compared to NG,grazing reduced the height,coverage,density and aboveground biomass of herbaceous communities.No significant changes in the height,density and aboveground biomass of shrub communities under grazing treatment,although the coverage showed a trend of initially increasing and then decreasing.3)Compared to the NG area,grazing significantly increased the Shannon-Wiener,Margalef and Simpson indices of the herbaceous community,while significantly reduced the Shannon-Wiener index of the shrub community.4)Aboveground biomass was positively correlated with the Shannon-Wiener and the Margalef indices in all areas.It was positively correlated with the Pielou index in NG,LG,and MG areas,but shows no correlation in the HG area.It was negatively correlated with the Simpson index.5)The density of seedlings of the Tetraena mongolica population was higher in the MG and HG areas compared to the NG area.In summary,the structure and function of Tetraena mongolica plant communities are affected by grazing behavior,with the herbaceous community showing a more significant response than the shrub community.Therefore,MG is beneficial for controlling the herbaceous community and protecting Tetraena mongolica populations.

Technical Application

Application of Generalized Additive Model Based on Meteorological Factors in Forest Fire Prediction in Fujian Province

CHEN Guofu, LI Chunhui, CHEN Zhenxiong

2024,(4):  94-102.  doi:10.13466/j.cnki.lczyyj.2024.04.011

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Predicting forest fire occurrences is crucial for fire prevention and management.This study used historical forest fire and meteorological data from Fujian Province(from 2010 to 2020)to apply the Logistic Regression Model and Generalized Additive Model(GAM)with six types of smooth spline bases[Gaussian Process Smoothing Spline Basis(GP),Cubic Regression Spline Basis(CR),Thin Plate Regression Spline Basis(TP),Duchon Spline Basis(DS),B-Spline Basis(BS),and P-Spline Basis(PS)]to predict forest fire occurrences.By comparing the performance of these models,their effectiveness in forest fire prediction was evaluated.The results indicate the following.1)The logistic regression model achieved an accuracy of 74.80% on the training set and 75.97% on the test set,demonstrating its baseline performance.Overall,the predictive accuracy of the GAM was generally superior to that of the Logistic Regression Model,with the TP spline basis-based GAM performing the best.Its accuracy on the training and test sets was improved by 3.86% and 2.52%,respectively,compared to the logistic regression model.2)Based on the optimal GAM,the forest fire risk levels in Fujian Province are delineated.The results revealed that areas with moderate to high fire risk are primarily concentrated in the northwest and southeast regions,while the Western and Eastern regions exhibit low fire risk.GAM arebetter at capturing complex nonlinear relationships,making them suitable for predicting forest fire occurrences in complex ecological environments.

Response of Fraxinus malacophylla Seedling Growth and Root morphological Characteristics to Simulated Variations in Precipitation during the Dry Season

WEI Xinglan, CHA Xiaofei, LUO Runwen, LUO Kaihua, GUO Huanxian, SUN Lijuan, DONG Qiong

2024,(4):  103-112.  doi:10.13466/j.cnki.lczyyj.2024.04.012

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To investigate the effects of varying precipitation patterns on the growth and root morphological characteristics of Fraxinus malacophylla seedlings during the dry season,artificial precipitation simulation experiments were conducted.1)During the first stage of the dry season(November to the next January),belowground biomass,total biomass,and root-crown ratio,total root length,and root surface area increased asprecipitation levels rose;provided the precipitation interval remained constant.However,when the precipitation interval was extended from 5-day intervals(T)to 10-day intervals(T+)underthe same precipitation,the total root length,root surface area,root volume,and specific root length all decreased.2)During the second stage of the dry season(February to April),total root length initially increased and then decrease as precipitation levels rose,given a constant precipitation interval.Aboveground biomass increased with prolonged interval at the same total precipitation level.3)Under different precipitation treatments,total root length consistently increaseed over the course of dry season,whereas root surface area,root volume,average root diameter,and specific root length gradually decreased.This study demonstrated that precipitation was the primary factor in the different precipitation change experiments,and the precipitation interval played a secondary role,and they were interdependent.The mechanisms of seedling growth and root morphology characteristics of Fraxinus malacophylla responded differently to the precipitation change with the duration of the dry season.

The Ecosystem Service Value and Changes of in the Mu Us Sandy Land

WANG Tingqin, CHEN Zimeng, CHENG Linsong, ZHAO Zheng, XIA Jianxin

2024,(4):  113-125.  doi:10.13466/j.cnki.lczyyj.2024.04.013

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The governance of the Mu Us Sandy Land is one of the key components of the shelterbelt program in northeast,north,and northwest China.Utilizing the ecosystem service value equivalent table per unit area and the sensitivity coefficient model,this study evaluates and analyzes the dynamic changes and characteristics between land use and ecosystem service value in the Mu Us Sandy Land.The research reveals the response of ecosystem service values to land-use changes.The results show that:From 2000 to 2020,there was a significantly changed in the land use structure of the Mu Us Desert,primarily characterized by the continuous decrease of grassland and water areas with negative dynamics and the corresponding increase in construction land area,which is a key factor leading to the decrease in total ecological service value.Apart from hydrological regulation and food production,the value generated by various ecological services has shown varying degrees of decline.Particularly,for the Mu Us Sandy Land,the contribution of grasslands to the overall ecosystem cannot be overlooked.

Site Selection for Forest Fire Prevention Video Monitoring Points Based on Visual Field Analysis

HU Yuyan, GAO Changjian, WANG Hailong, SHENTU Yucheng, XU Da

2024,(4):  126-134.  doi:10.13466/j.cnki.lczyyj.2024.04.014

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Video monitoring plays a crucial role in forest fire monitoring system,and placing video monitoring points can effectively enhance the level of forest fire detection.This study focuses on Yuhexian County,Lishui City,Zhejiang Province.Using digital elevation models(DEM),visual field analysis and reverse visual field analysis techniques were employed to assess the effectiveness of placing video monitoring probes within different visibility ranges.The study identifies a need for 86 additional video monitoring points,comprising 29 dual-spectrum probes and 57 spherical probes.Following optimization,the coverage area of monitored forest land increased from 11.67% to 85.12% of the county's vegetated forest.This optimization plan offers a scientific foundation for enhancing the layout of the forest fire video monitoring system in Yuhexian County,and serves as a technical reference for other regions to improve forest monitoring coverage using geographic information technology.

Effects of Nitrogen Application and Mixed Planting of Nitrogen-Fixing Tree Species on Phosphorus Distribution and Growth of Eucalyptus urophylla×grandis

LI Zihua, YAO Xianyu, LIAO Zihua, XIONG Junfei, YE Shaoming

2024,(4):  135-146.  doi:10.13466/j.cnki.lczyyj.2024.04.015

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Mixing nitrogen-fixing tree species with Eucalyptus urophylla×grandis can enhance soil nitrogen(N)content.However,excessive N may disrupt the N:P ratio and intensify phosphorus(P)limitation for Eucalyptus urophylla×grandis.Understanding the effects of N-fixing tree species on soil N and P content and Eucalyptus urophylla×grandis P nutrients is essential for sustainable nutrient management in Eucalyptus urophylla×grandis plantations.This study included three treatments:Eucalyptus urophylla×grandis mixed with N-fixing species(ME),pure Eucalyptus urophylla×grandis plantation with N application(NE)and pure Eucalyptus urophylla×grandis plantation without fertilization(PE).And this study analyze the differences and seasonal dynamics of soil N and P levels,Eucalyptus urophylla×grandis biomass,P concentration and P accumulation in Eucalyptus urophylla×grandis plants.The results showed that both ME and NE treatments significantly increased soil total N content(from 36% to 46%),available N content(from 20% to 40%),Eucalyptus urophylla×grandis biomass(from 16% to 23%)and P accumulation(from 16% to 36%)compared to the PE treatment.In the ME treatment,the soil available N:P ration remained balanced,whereas it significantly increased in the NE treatment.The P concentration in Eucalyptus urophylla×grandis organs showed the order of ME>PE>NE.Correlation analysis revealed that leaf P concentration was influenced by soil available P(16.42%)and the soil available N:P ratio(15.13%).Both N application and introduction of N-fixing tree species treatments significantly increased soil N content.However,N application decreased phosphorus concentration and AP in all organs of Eucalyptus urophylla×grandis,which aggravated the phosphorus limitation in the later stage of Eucalyptus urophylla×grandis.The mixed treatment of nitrogen-fixing tree species maintained the balance of AP content and the AN:AP ration,alleviating N and P limitations and promoting long-term Eucalyptus urophylla×grandis growth.In the short term,introducing nitrogen-fixing tree species improved soil N and P stability and promoted Eucalyptus urophylla×grandis growth.

Effects of Rootstock on Ornamental Characteristics and Physiological Indices of New Triadica Cultivars

WANG Tiantian, ZHOU Qi, ZHUGE Fei, JIN Yuehanbao, LIN Ming, LI Yingang

2024,(4):  147-155.  doi:10.13466/j.cnki.lczyyj.2024.04.016

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The leaf color changes in Triadica sebifera are diverse,while Triadica cochinchinensis exhibits fast growthand strong stress resistance.In order to investigate the effects of two rootstocks,Triadica sebifera and Triadica cochinchinensis,on the ornamental and physiological indicators of new Triadica cultivars,and to screen for more suitable rootstocks for the asexual propagation of each new cultivar,this study adopted a single factor random block design,using four new Triadica cultivars,namely ‘HongziJiaren’,‘Canlan’,‘Pu Dazi’,and ‘Manshan Hongbian’,as experimental materials.They were grafted onto the two rootstocks,and their growth indicators,ornamental characteristics,and physiological changes during leaf discoloration were measured.1)The type of rootstock had no significant effect on the height and diameter growth of the cultivars,but had a significant impact on ornamental traits such as ornamental period,crown size,number of leaves,leaf color parameters(L^*,a^*,b^*),and physiological indicators such as carotenoids and anthocyanins.2)Ornamental characteristics,leaf color parameters,and the changes in physiological indicators of ‘Canlan’,‘Pu Dazi’,and ‘ManshanHongbian’cultivars grafted onto Triadica sebifera discolor rootstocks under T2,T6,and T8 treatments with Triadica cochinchinensis as the rootstock were better than those of T1,T5,and T7 treatments with Triadica sebifera as the rootstock.In contrast,the T3 treatment with‘HongziJiaren’ grafted onto Triadica sebifera performed better,with its discoloration period occurring 14 days earlier.Among all treatments,the combination of Triadica sebifera/‘HongziJiaren’(T3)yielded the best results,with the earliest entering the full leaf color changing period and an ornamental period of up to 24.33 days.Overall,Triadica cochinchinensis as rootstock is more beneficial to improving the ornamental effects of new Triadica cultivars.

Research Briefing

Analysis of Weed Flora Characteristics in Macadamia integrifolia Orchards in Guangxi

WANG Zhenchuan, LU Shuowen, HUANG Riming, WEI Pingping, ZHOU Chunheng, HUANG Xiyun, TAN Qiujin

2024,(4):  156-163.  doi:10.13466/j.cnki.lczyyj.2024.04.017

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Understanding the floristic characteristics of orchard weeds c is essential for supporting effective management,ecological protection,and development of orchard forestry environments.Using field surveys and literature reviews,we analyzed the composition,geographic distribution,and invasiveness of weeds in Macadamia orchards across Guangxi.Theresults identified 77 weed species from 33 families and 70 genera,including 30 invasive alienspecies from 13 families and 28 genera,primarily from the Asteraceae and Poaceae.The distribution patterns of weed families and genera show significant differences among geographical types,with tropical characteristics dominating at the family level and relatively simple overall geographic composition.Based on the frequency of occurrence in different regions,15 common genera of weeds were identified in Macadamia orchards in Guangxi,many of which were dominated by invasivealien species,indicating a high degree of invasiveness.Among the 30 identified invasive alien weed species,the harmfulness of 14 remains undetermined to be clarified through further investigation.Further in-depth and comprehensive research is required to improve weeds management strategies and mitigate the potential threats to orchards forestry and the ecological environment.

The Development Experiences of the Flower Industry in the Netherlands and Its Implications for China

XIANG Yue, LIU Ping

2024,(4):  164-170.  doi:10.13466/j.cnki.lczyyj.2024.04.018

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The flower industry,as a burgeoning sector that contributes to China's rural revitalization efforts,plays an important role in promoting economic prosperity,enhancing social well-being,and strengthening the construction of ecological civilization.It is currently at a key turning point,transitioning from high-speed development to high-quality development,while facing major challenges such as an incomplete industrial chain,weak quality supervision,low levels of scientific and technological innovation,and insufficient policy support.The Netherlands,as a global leader in the flower industry,offers advanced development practices and successful experiences that are highly relevant for promoting the sustainable growth of China's flower industry.This paper summarizes the current situation and successful experience of the Netherlands flower industry,and proposes development strategies for China's flower industry.By accelerating the optimization and upgrading of the flower industry,improving the quality management system,strengthening scientific and technological support,and enhancing government support,China's flower industry can achieve high-quality,sustainable development.