Forestry carbon ticket is a novel approach to realizing the value of forestry carbon sink projects and encouraging progress toward the twin goals of carbon peak and carbon neutrality.In the context of advancing green development,it examines the current status and necessity of regulating forestry carbon ticket in China,drawing insights from the legal practices observed in Sanming City,Fujian Province,and similar regions.Additionally,an analysis is conducted to identify the practical challenges inherent in the forestry carbon ticket system.Under the policy objective of actively and prudently advancing carbon peak and carbon neutrality,the legal regulation of forestry carbon tickets in China is essential.The usufruct attribute of forestry carbon tickets related to carbon emission reduction is clarified.Moreover,this framework can contribute to the establishment of a supervisory system for multi-subject collaboration,ensuring the orderly development of the forestry carbon ticket market,and fostering the creation of a beautiful China.

The implementation of the Three-North(i.e.,Northeast China,North China and Northwest China)Shelterbelt Forest Program from 2001 to 2020 has yielded significant results,and the dynamic evaluation of the implementation effect of the Three-North Shelterbelt Forest Program at this stage facilitates precise measurement of future objectives and tasks focus.By applying dynamic weighting and normal cloud models,we constructed a multi-level indicator system to comprehensively evaluate the implementation effect of the Three-North Shelterbelt Forest Program from 2001 to 2020,and selected the grey system prediction model to accurately predict the first-level effect response index from 2024 to 2028.The results show that:1)The response indexes for project objectives,benefits,and sustainability show a steady upward trend,of which the largest increase is the index of project benefits,and the smallest increase is the index of project objectives.2)The overall evaluation of the Three-North Shelterbelt Forest Program from 2001 to 2020 is positive,which indicates that the project's comprehensive benefits are significant in this period.3)The comprehensive evaluation and prediction results for the Three-North Shelterbelt Forest Program from 2024 to 2028 show a consistent upward trend in both project goal and sustainability indices.Focusing the evaluation on project objectives,benefits,and sustainability,the index system for evaluating the implementation effect of the Three-North Shelterbelt Forest Program from 2001 to 2020 has been enhanced and refined.

The assessment of forest ecosystem service value and its changes is of great practical significance for the protection and management of forest ecosystems,and can provide a reference for achieving regional economic-social-ecological synergistic development.Based on remote sensing data and related mapping data,the ecosystem service value(ESV)accounting method was used to assess the forest ecosystem service function of Qilian Mountain National Nature Reserve and identify its hotspots of change from 1980 to 2020.The results show that:1)Qilian Mountain National Nature Reserve is rich in forest resources,with a total forest area of about 636 600 hm² and a forest coverage rate of 14.44%.Over time,the overall area has shown an increasing trend over the past 40 years,with a total increase of about 11,300 hm² and a growth rate of 1.81%.2)The forests in the reserve possess great ecosystem service value,and from the perspective of time change,the ESV increased from 45 444 000 000 Yuan to 60 628 000 000 Yuan from 1980 to 2020,with a growth rate of 33.41%,which has shown an obvious increasing trend.From the perspective of the ESV contribution of different ecosystem types,forested land>shrubland>thin forest land>other forest land.In terms of specific ecosystem service values,soil conservation>water conservation>flood storage>tourism and cultural services>carbon sequestration>windbreaks and sand solidification>forest product production.3)Based on the prediction of hotspot areas of ecosystem service function and value change in the reserve,the value of regulating services is extremely vulnerable to the ecosystem change.The hotspot areas for the value change of provisioning services and cultural services remain stable in general,while areas prone to decrease account for 44.21% of the total protected area,which requires close attention.The results of the study provide important scientific insights for forest ecosystem assessment in Qilian Mountain National Nature Reserve.

The accurate estimation of forest volume is the basis for improving the level of sustainable forest management.Based on the airborne laser point cloud data,49 laser point cloud feature variables were generated.Combined with the ground survey sample data,three methods of fixed parameter,Pearson screening,and stepwise regression screening were used to screen out the independent variables used for modeling,and then linear and nonlinear regression fitting was used to establish the accumulation models of the three main tree species in Hainan Tropical Rainforest National Park.The results show that:1)Among the linear and nonlinear models of the three tree species(Acacia confusa,Hevea brasiliensis, Eucalyptus robusta),the accuracy of the optimal models was above 0.83 with A.confusa and E.robusta having better nonlinear models,and H.brasiliensis having a better linear model.2)The height class variable has the greatest influence on the accumulation model.The intensity and density of the laser point cloud have a greater influence on the accumulation model,and the coverage class variable also has some influence.The structural parameters obtained from airborne LiDAR data play an important role in modeling,and can be popularized and used in related operational work in the future.

This study explores the response of eco-chemometrics of Pinus yunnanensis to elevation and investigates the relationship between nutrient elements in different organs of P.yunnanensis and soil nutrient elements,providing theoretical support for the management of P.yunnanensis forests.The natural secondary forests of P.yunnanensis at different elevations in Northwest Yunnan were studied,carbon(C),nitrogen(N),phosphorus(P)and their stoichiometric characteristics in different organs and rhizosphere soil of P.yunnanensis at different elevations(1 900 to 2 900 m)were compared.The results showed that the N content of needles was higher than that of fine roots,and the N∶P ratio of both needles and fine roots was less than 14.Additionally,the contents of soil C(13.037 g/kg)、N(1.446 g/kg)and P(0.473 g/kg)were lower than the average levels of topsoil in China.The contents of N,P,C∶N,C∶P,N∶P in rhizosphere soil were significantly affected by elevation,while the nutrient contents and stoichiometric characteristics of needles and fine roots of P.yunnanensis showed no significant changes across elevation gradients.The contents of C and C∶N in needles of P.yunnanensis belong to sensitive steady state and weak steady state respectively,the other indexes belong to absolute steady state.While the contents of C,N,P,C∶N,C∶P,N∶P in fine roots of P.yunnanensis were not significant,all belonging to absolute steady state.The growth of P.yunnanensis in poor soil with low nitrogen and phosphorus,and its growth is mainly restricted by N,but P.yunnanensis adapts to the change of elevation gradient by increasing N absorption into plants and distributing more N into needles P.yunnanensis has good adaptability to the rhizosphere soil environment in the range from 1 900 to 2 900 m.This study revealed the adaptability of stoichiometric characteristics of P.yunnanensis to elevation in western Yunnan,and provides data to support further research on nutrient distribution pattern and environmental adaptability of P.yunnanensis.

A regional nonlinear mixed site index model of Cunninghamia lanceolata plantations with site factors was established to provide a reference for predicting the height of Cunninghamia lanceolata in the region.This study is based on data from the analysis of 307 disc groups from 45 dominant trees across 4 provinces,selecting five common tree height-age growth equations.Using quantitative theory I,nonlinear mixed model and other methods,the mixed model of nonlinear site index with initial site type was constructed by using random effects.Finally,the mixed model of nonlinear site index with site type group was further developed by K-means clustering.The results showed that altitude,soil type,aspect,and slope position were the site factors that significantly affected the tree height.The Gompertz model was selected as the basic model,showing the best fitting effect,with an R² of 0.653.Compared with the basic model,the accuracy of the nonlinear site index model with the initial site type is improved by 28.02%.Compared with the basic model,the R² of the nonlinear site index mixed model with site type group was increased by 37.21%.After cross testing of the model,the accuracy of the model was high based on the initial site type and clustering,which confirmed the practicability of the model.The establishment of a nonlinear site index mixed model provides a feasibility for the site quality evaluation and compilation of site index tables for Cunninghamia lanceolata plantations at the regional scale.

Enclosure is an effective management method for ecological restoration of degraded grassland.After enclosure,the vegetation community changes,which affects the above-ground biomass and litter production.Studying the characteristics of litter decomposition and nutrient release can provide scientific theoretical support for the subsequent restoration and management of desertification grassland.The decomposition and nutrient release of Leymus chinensis litter under two enclosure measures were studied by selecting seasonal enclosure and complete enclosure of desert steppe and setting up a natural decomposition experiment of L.chinensis litter bag.The results showed that:1)The decomposition constant of seasonal enclosure (k=0.025 87),was greater than that of complete enclosure (k=0.018 32).The decomposition of L.chinensis litter under seasonal enclosure measures was faster,and the decomposition rate showed a trend from slow to fast.The turning point of decomposition was the 180 th day.2)The decomposition process of L.chinensis litter can be well fitted to the Olson index regression model(R²>0.97).Through simulation,under seasonal enclosure and complete enclosure measures,50% decomposition of L.chinensis takes 2.23 years and 3.15 years respectively,and 95% decomposition takes 9.65 years and 13.62 years respectively.Seasonal enclosure has obvious advantages.3)The element release of seasonal enclosure and complete enclosure showed the lowest organic carbon(OC)value,which was 44.24% and 52.13%,respectively.The total nitrogen(TN)accumulation index was 71.67% and 61.35%,respectively.The total phosphorus(TP)content was 77.41% and 57.08%,respectively.The change of carbon-nitrogen ratio was less than that of complete enclosure,and the change of nitrogen-phosphorus ratio was the opposite.The results showed that seasonal enclosure was beneficial to the decomposition of L.chinensis litter in desert steppe.The enrichment of C,N and P elements is closely related to the release and decomposition of litter.The effect of seasonal enclosure is obviously better than that of complete enclosure.

Efficient forest disturbance detection methods can prevent and mitigate forest disasters in time and protect the ecosystem.To address the issue of forest interference in mountainous areas,which is often affected by terrain when integrating multi-source data,this study develops a slope direction classification algorithm to delineate the detection area.This mitigates the effect of terrain relief on the radar rate of change(RCR).A novel forest disturbance detection method was proposed on the basis of the fusion of synthetic aperture radar(SAR)and optical satellite data,utilizing an enhanced RCR approach with NDVI time series.The results were as follows:1)The enhanced RCR methodology markedly expands the detection area 19.48% through the slope classification method,encompassing a greater scope of interference areas and enhancing the detection accuracy.2)The overall detection accuracy based on the fusion data of SAR and optical satellite is 89.24%,which is 11.11% and 13.32% higher than that of SAR and optical satellite with only a single sensor.Compared with the single-sensor method,this research method can obtain rich,continuous detection information under different time and weather conditions,and it has greater potential and advantages in improving the detection capability of forest disturbance,which can provide more comprehensive and accurate information support for forest resource management and ecological protection in the future.

In broad-leaved mingled forest with multiple tree species and complex structures,constructing a high-precision site index model based on the diameter at breast height of dominant trees is a key scientific challenge in evaluating the site quality of these forests.The Populus davidiana and Betula platyphylla broad-leaved mingled forest in Mulan Weichang,Hebei Province is selected as the research object.Based on the survey data from 70 standard plots(each standard land area is 0.06 hm²),using the nonlinear least squares method,BP neural network,and nonlinear mixed-effects model,three parameter estimation methods are used to construct the site index models of P.davidiana and B.platyphylla broad-leaved mingled forest.Using Mean Square Error(MSE),Root Mean Square Error(RMSE),Mean Percentage Bias(MPB),Coefficient of Determination(R²),Adjusted Coefficient of Determination($R_{\mathrm{adj}}^{2}$),Akaike Information Criterion(AIC),Bayesian Information Criterion(BIC),and Negative Twice the Log-Likelihood(-2LL),the impact of different parameter estimation methods on model prediction accuracy is compared.The results show that:1)Among the five candidate equations,the logistic equation with the diameter at breast height of dominant trees as the independent variable is the optimal site index base model for the mingled P.davidiana and B.platyphylla broad-leaved forest,and the MSE,RMSE,MPB,R²,$R_{\mathrm{adj}}^{2}$ of its model are 9.071 7,2.269 6,11.972 9,0.583 8,0.569 9,respectively.2)Compared with the nonlinear least squares method and BP neural network,the site index model of P.davidiana and B.platyphylla broad-leaved mingled forest based on the nonlinear mixed-effects has higher prediction accuracy.The MSE,RMSE,MPB,R²,$R_{\mathrm{adj}}^{2}$ of the model are,5.477 4,1.779 4,9.161 4,0.782 8,0.761 7,respectively.The site index model constructed with the diameter at breast height of dominant trees as the independent variable can be used to evaluate the site quality of mingled forests.

National forest inventory data are important resources for understanding the dynamics of forest carbon cycling at regional and global scales.Developing growth models of carbon storage has a great importance in practice,which can provide a decision-making basis for promoting high-quality development of forestry and grassland industry,and implementing the carbon emission peak and carbon neutralization strategy.Based on the carbon storage dataset of 780 sample plots from the ninth national forest inventory of China,the growth model of carbon storage for Pinus tabuliformis plantation was developed by using a weighted nonlinear regression method.And the effects of two climate factors:Mean annual temperature(MAT)and mean annual precipitation(MAP)on carbon storage growth were analyzed by using a variable parameter method.The results showed that:1)The mean prediction error(MPE)of growth models of carbon storage for P.tabuliformis plantation was less than 5%,and the total relative error(TRE)was approximately less than 1.00%.2)The age of inflection point and quantitative maturity were 30 years and 53 years,respectively,when the current annual increment and average increment of carbon storage reached a maximum of 1.19t/hm² and 0.94 t/hm²,respectively.3)The MAP had an impact on the growth process of carbon storage and the capacity of carbon sequestration for P.tabuliformis plantation,and the degree of its impact varied in different MAP levels and variation.The carbon storage gradually decreased with the decrease of MAP,and the annual mean of carbon storage decreased by approximately 3.64%for the P.tabuliformis plantation,when the MAP decreased by every 100 mm.It is essential to employ scientific management strategies to fully explore and develop the carbon sequestration potential of P.tabuliformis plantation.The change pattern of carbon storage with forest age at different MAP levels is an important basis for determining a reasonable management cycle of P.tabuliformis plantation.

Larix gmelinii is the main afforestation tree species in Daxing 'anling.It examines the biomass,carbon fixation and oxygen release functions across different forest ages to provide a foundation for the rational and scientific management of Larix gmelinii in this area.The biomass and carbon fixation and oxygen release functions of different forest ages of Larix gmelinii were analyzed by field investigation and laboratory test.The results showed that:1)The stand structure of Larix gmelinii changed with the increase of forest age.Between ages 5 and 35 years,crown width increased from 1.11 m² to 32.71 m²,with an average annual growth rate of 1.05 m² per year.The diameter at breast height ranged from 1.11 to 27.1 cm,and the growth rate showed a trend of first being fast and then slow.2)The age from 5 years to 35 years,the biomass per plant was 0.25 to 411.73 kg per plant.The trunk consistently accounted for the dominant portion of a single plant’s biomass,holding an absolute advantage in aboveground biomass.3)The carbon fixation and oxygen release functions of Larix gmelinii showed an upward trend with the increase of forest age.When the forest age was 35 years,the average annual carbon fixation was 119.02 kg,and the oxygen release was 318.64 kg.The biomass and carbon fixation and oxygen release functions of Larix gmelinii showed significant positive changes with the increase of forest age.Therefore,the continuous optimization and protection of Larix gmelinii have substantial potential for improving ecological conditions.

The Yellow River basin in Henan Province is an important biodiversity protection hotspot with an important natural protection value.In order to identify the suitable habitats and protection gaps of key protected wild species in the Yellow River basin of Henan Province,this paper simulated and predicted the potential distribution areas of six key protected wild species and 46 environmental factors under three climate scenarios in the benchmark period(1970-2000)and two future periods(2041-2060,2081-2100)based on the MaxEnt optimization model,and identified the protection gaps based on the spatial distribution data of nature reserves.The results showed that the seasonal changes of altitude and precipitation were the dominant environmental factors affecting the geographical distribution of key protected wild species.In 2090 period(2081-2100),the suitable habitat area of key protected wild species increased the most under the SSP585 climate scenario compared to the benchmark period,indicating that temperature change significantly affects the suitable habitat range of key protected wild tree species within the research area.The existing nature reserves have covered 70% of the suitable habitats of key protected wild species,and the core area of protection gap was mainly located in the Xiong'er Mountains in the Yiluo River basin and the intersection between the Xiong'er Mountains and the northern foot of Funiushan Mountain in the west of Henan Province.This study provides important theoretical support for biodiversity protection and nature reserve planning in the Yellow River basin in Henan Province.

To explore the optimization of the KNN algorithm and use Sentinel-2 for large-scale estimation of forest AGB.In this study,Xiangtan City,Ningxiang City and Wangcheng District in Changsha City in Hunan Province were selected as the study area,and Quercus×Leana and Cunninghamia lanceolata were used as the target tree species.A KNN optimization algorithm based on the optimal K-value(Optimal-K KNN,OK-KNN)was proposed to achieve remote sensing estimation and spatial mapping of forest AGB,using Sentinel-2 as the source of remote sensing data in combation with ground survey data.To examine the performance of the OK-KNN model,the OK-KNN model was compared with the traditional KNN model,the distance-weighted KNN(DW-KNN)model and the multiple linear regression(MLR)model,and the three metrics-coefficient of determination(R²),root mean square error(RMSE)and relative RMSE(rRMSE)were calculated for evaluating the model's estimation results.The results showed that the three KNN models had better forest AGB prediction performance than the MLR model,and among the three KNN models,the OK-KNN model obtained the optimal estimation results,with the R² of Cunninghamia lanceolata samples improved by 17.02% and 13.04%,and the RMSE reduced by 17.21% and 7.03%,respectively,when compared to the ordinary KNN and DW-KNN models;R² for Quercus×Leana samples improved by 20.93% and 13.04%,and RMSE decreased by 15.17% and 9.24%,respectively.This study demonstrates that the optimal K-value adaptive selection of different samples can be realized using the OK-KNN model,which effectively improves the estimation accuracy of forest AGB.

Fagus lucida is a rare and endemic tree species in China.Predicting the potential suitable area of Fagus lucida in Hunan Province and exploring the dominant environmental factors influencing its distribution is of significant importance for its conservation.Based on 117 field surveys of the distribution points of Fagus lucida in Hunan,22 environmental variables affecting its distribution were selected.The MaxEnt maximum entropy model was used for prediction.1)The average AUC value of the MaxEnt model is 0.933,indicating reliable predictive accuracy making it effective in predicting suitable areas for Fagus lucida.2)The four key factors that limit the current distribution of Fagus lucida in Hunan are the seasonal variation coefficient of precipitation,average temperature in the driest season,annual rainfall,and average temperature in the wettest season.3)The total suitable habitat area for Fagus lucida in Hunan Province is 9.30×10⁴ km² with 3.10×10⁴ km² being highly to moderately suitable areas,mainly distributed in the Xuefeng Shan,Nanling,and Heng Shan mountain ranges,including the western part of Shaoyang,the southern part of Huaihua Shi,the northwestern part of Loudi,the southwestern part of Yiyang,and the northern part of Hengyang.The area of low suitability is 6.20×10⁴ km²,mainly concentrated in the low-altitude areas of Changde,Yueyang,Yiyang,Changsha and Hengyang.Climate is the main factor affecting the geographical distribution pattern of Fagus lucida in Hunan.In areas such as Shaoyang,Huaihua Shi,Loudi,Hengyang and Yiyang,annual precipitation is sufficient,and there is low seasonal precipitation variability,especially in high-altitude sunny or semi-sunny slope,which may be suitable for the introduction and protection of Fagus lucida.

The litter is a vital component of ecosystems and its decomposition process profoundly affects soil carbon input and the soil respiration process.In this experiment,Longxiang Mountain in Jiaozuo was selected as the study area,which is located in the southern Taihang Mountains and belongs to the temperate hilly region of central China.Sample sites were established along altitudes ranging from 148 to 827 m and on both sunny and shady slopes.The study focused on the existing quantity of surface litter,carbon and nitrogen stoichiometric characteristics,and analyzed its potential nutrient return capacity and key influencing factors.The results showed that:1)The average value of the existing litter biomass on the surface of Longxiang Mountain is 540.81±388.00 g/m²,and there is no significant difference in the existing litter biomass among different altitude gradients below an altitude of 800m.Also,the existing litter biomass increased significantly above 800m(P<0.05).2)Among the four vegetation types in Longxiang Mountain,temperate evergreen coniferous forests were mainly distributed above an altitude of 800 m,and their surface litter biomass was the highest[(1 038.95±289.31 g/m²)],which was the significantly higher than that of deciduous broad-leaved forests,scrubs and meadows(P<0.01).Additionally,there is a highly significant positive correlation(r=0.96,P<0.01)between surface litter biomass and the maximum nitrogen return from litter.3)The litter's maximum nitrogen and carbon return capacity,soil N content,and altitude were the main driving factors affecting the existing quantity of surface litter.In addition,vegetation type also has an important direct effect on the existing quantity of surface litter.In conclusion,the litter of the plant community in Longxiang Mountain in Jiaozuo is a critical factor,and the vegetation type plays an important role in its regulation process.

With the improvement of living standards and the change in people's life philosophies,urban and rural residents have an increasingly strong demand for urban non-motorized traffic spaces,which are typically represented by greenways.Evaluations of walkability can help assess the effectiveness of greenway construction,implement targeted improvements,and thereby promote the development of Park City.Taking the five sections of the greenway of Luopu Park in Luoyang as the research object,the article formulated an evaluation system covering 4 first-level indicators including "convenience,functionality,comfort and attractiveness",as well as 18 second-level indicators such as "time consumption for arriving".Adopting the Analytic Hierarchy Process(AHP),the article calculated the comprehensive evaluation index.At the same time,the calculation of obstacle degree was introduced to diagnose the obstacle factors of greenways.The results showed that the pedestrian-friendliness of the Luopu Park greenway was generally good.The comprehensive evaluation grade of No.2 was level I,and the others were level II.The biggest obstacle factors of each section were "road surface integrity,rest(rain shelter)facilities,user satisfaction with walking experience,and road surface integrity",and "time consumption for arrival".Through the evaluation,the effectiveness and existing issues of Luopu Park greenway regarding walkability were identified which could be beneficial for improving the walkability of each section during the construction of Park City in Luoyang.

Exploring the physiological response of Sanchezia oblonga to biotic and abiotic stress,in order to provide a scientific basis for carrying out stress resistance breeding or pest management of garden plants.The study focused on the leaves of S.oblonga under the biotic stress feeding of Achatina fulica and the abiotic stress of leaf cutting.Chlorophyll and tea polyphenol content as well as phenylalanine ammonia lyase activity of the leaves were measured under different growth conditions after leaf cutting and snail feeding stress.The results showed that A.fulica prefer to feed on the leaves of S.oblonga,and their feeding amount is large,which often leads to the leaves being completely consumed,seriously affecting the photosynthesis of S.oblonga.The leaf cutting stimulation and snail feeding stress have significant effects on the chlorophyll content,tea polyphenol content,and phenylalanine ammonia lyase(PAL)activity of the leaves of S.oblonga.At 3,9 and 15 hours after snail feeding and leaf cutting stimulation stress can induce more chlorophyll and tea polyphenols to be synthesized in the leaves of S.oblonga.However,PAL activity decreased rapidly and was significantly lower than that of the control group,suggesting that phenylalanine was accumulating to promote wound repair.The effects of snail feeding on chlorophyll,tea polyphenol content and PAL activity were more rapid than those induced by leaf cutting abiotic stress.In conclusion,the physiological response of S.oblonga after leaf cutting stimulation and snail feeding stress showed that the content of chlorophyll and tea polyphenols increased,and the activity of PAL was inhibited.

Mastering the characteristics of vegetation communities in the Hungou area can provide a reference for the deeper research into forest community succession law and internal mechanism in Hungou,and provide a scientific basis for the study of the protection of zonal forest in the warm temperate zone.Using the method of route survey and sample survey,the community types were determined by important values.The species composition,floristic characteristics and community characteristics of the Hungou area in Lishan National Nature Reserve were studied and systematically analyzed and the spatial pattern of vegetation communities,such as vertical distribution and slope distribution was analyzed.The results showed that:1)There were 443 species of vascular plants in the study area,belonging to 93 families and 267 genera.2)The distribution types of seed plant families can be divided into 10 types.The distribution types of genera can be divided into 14 types,and the distribution types of species can be divided into 11 types.It is divided into 6 groups of vegetation type,9 vegetation types,28 formations and 43 associations.3)Zonal vegetation is broad-leaved forest in the warm temperate zone,but plant communities with subtropical components are scattered.The research results have preliminarily grasped the characteristics of vegetation communities in the Hungou area.