From the viewpoint of tediousness and professionalism of forest fuel load investigation,a stratified sampling system for the plot survey of forest fuel loads at national and provincial scale were developed based on five commonly used indicators,namely vegetation area,tree species,stand origin,age group and canopy density.Within each specific plot,the fuel loads of tree-layer can be estimated by using the data of individual tree survey combined with the algometric biomass model or the biomass expansion factor,while fuel loads of shrub-,herb-,litter- and humus-layer should be jointly estimated by the quadrat survey and the data of sample moisture content.This method has important guidance and reference significance for the survey and estimation of forest fuel loads at national or regional scale.
By constructing the evaluation indicator system and evaluation method of ecological security,the ecological security index,state and pressure indicators of forest,grassland,wetland,snow area and desert ecosystems of the Qinghai-Tibet Plateau from 2015 to 2021 were calculated.The results showed that the ecological security level of the Qinghai-Tibet Plateau was between 0.6 and 0.8,and the ecological security index of Tibet was higher than that of Qinghai.Based on this,the paths to improve the ecological security of the forest,grassland,wetland,snow area and desert ecosystems on the Qinghai-Tibet Plateau were put forward,also the strategy to ensure the ecological security of the Qinghai-Tibet Plateau was pointed out.
The characteristics of forest land protection and utilization planning were summarized.Based on the new round of forest protection planning in Guizhou Province,this paper analyzed the issues such as the connection of forest land definition standards,the fusion of basic data sources,and the positioning of the planning development blueprint under the land space planning system.In order to link up and coordinate the land space planning,a new round of mechanisms and strategies such as the classification and coordination of provincial forest land protection and utilization planning,the scientific integration of linkage verification,and the conduction and guidance of spatial layout were proposed.
This paper took the forest land resources in Hainan Province as an example to carry out the practical research work based on the General Rules for Gradation and Classification of Natural Resources for the first time.This paper had created a classification index interpretation model that could not directly obtain data,which constructed an evaluation scheme for the classification of forest land in Hainan Province by the method of factor and correction,and clearly adopted the five grade and five class evaluation system.The results indicated that 18.2474 million hm2 of forest land was the phased achievement of the "The Third Land Survey" project in Hainan Province and there were 2.1252 million basic units for forest land classification and grading,with one grade of each plot.There were actually four grades from 1 to 4;The commercial forest land was 7.8809 million hm2,and there were actually five grades from 1-5;The forest land of public welfare forest was 10.3665 million hm2,and there were actually 1-5 levels.The evaluation results reflected the actual situation of forest land in Hainan,and provided a reference for the standardization and procedure of national forest land classification with the promotion of forest land resources protection and rational development and utilization.
The implementation of afforestation space based on territorial spatial planning is an effective way to systematically solve the conflict between afforestation land and other types of planning,and also an important basis for scientifically promote afforestation and implement fine management of afforestation.By analyzing the problems existing in the past afforestation planning,according to the requirements of constructing a unified territorial spatial planning system,this paper discussed the path of implementing afforestation space based on land and space planning to scientifically promote land greening.
Based on the analysis of the structural and functional characteristics of each region in Dianchi Watershed,the diagnosis of forest and grass ecological problems and the suitability evaluation of protection and restoration space,a pattern of forest and grass ecological protection and restoration in "three areas, one belt and multi-points" was proposed,by implementing 16 key projects of 6 key programs in total,including vegetation restoration in difficult sites in the western mountain of Dianchi Lake,construction of water source conservation forest and biodiversity protection in important water sources,vegetation restoration in rocky desertification area of Niulan River,construction of lakeside ecological belt around Dianchi Lake,construction of forest countryside and construction of supporting system.It can provide a reference for systematically carrying out forest and grass ecological protection and restoration in Dianchi Lake Watershed,scientifically delineating and rationally arranging green land,gradually restoring the ecosystem integrity of Dianchi Lake Watershed,improving the ecosystem service function and improving the ecosystem quality and stability.
Taking the plain afforestation in Daxing District of Beijing as an example,the plain afforestation is divided into three types: ecological conservation leading type,landscape recreation leading type and ecological corridor type.Through field research,data access,expert consultation,technical analysis and other methods for analysis,comparison and research,the following promotion strategies were proposed : For ecological conservation leading plots,strive to cultivate the goal of near natural forest through measures such as tending thinning,tree species replacement and establishment of conservation area;On the basis of giving full play to the ecological benefits of forest resources,the landscape and recreation leading plots need to build high-quality green spaces and add landscape spatial structure design such as roads and landscape nodes;For ecological corridor plots,improve the green ecological corridors on both sides of main roads and rivers in plain areas,pay attention to connecting habitat islands,and create habitat and migration conditions for small animals.
Based on the sample plot data from the forest resources inventory of Ganzhou City,the carbon density of Pinus massoniana forest was calculated by regional scale carbon budget model (CBM-CFS3),and the spatial distribution and influencing factors of carbon density were analyzed by geostatistics and multiple stepwise regression methods,respectively. The results showed that there were differences in the optimal stand age-accumulation equation for different forest types and origins of Pinus massoniana forests. In general,the Logistic model,Richards model and Gompertz model fit better than the Korf model. The total carbon density of the stand was 135.08MgC/hm2,in which the carbon densities of the vegetation layer carbon pool and the dead organic matter (DOM) carbon pool were 41.51MgC/hm2 and 93.57MgC/hm2,respectively. The vegetation layer carbon pool showed as trunk>branches>roots>leaves while DOM carbon pool showed as soil layer>litter>dead wood. The total carbon density of forest stands had a certain positive correlation in space,mainly concentrated in 106.73-161.16MgC/hm2. The area of the low-value carbon density area was larger than the high-value carbon density area,but there was no obvious regularity in space. Age group,average diameter at the breast height (DBH),canopy density and annual mean temperature were all highly significantly and positively correlated with the total carbon density of forest stands (P<0.01),so they were the main factors affecting carbon density. The growth model constructed by the sample plot data from the forest resources inventory was used to estimate forest carbon density in the CBM-CFS3 model,which was conducive to get a more comprehensive and accurate estimation of different carbon pools in regional forests. The vegetation factor was the main factor affecting its carbon density.
Using the "pressure-state-response (PSR)" model,this paper constructed an evaluation index system for the degradation degree of mangrove wetland ecosystem in Hainan according to the causal logical relationship of mangrove wetland degradation.Combined with the status and characteristics of Hainan mangrove wetland ecosystem,23 evaluation indicators were screened out,and three typical mangrove wetland ecosystems in Hainan were selected to evaluate the degree of degradation.The results showed that the three mangrove wetland ecosystems in Hainan had different degrees of degradation.The Dongzhaigang mangrove and Bamenwan mangrove were in mild degradation,while the Huachangwan mangrove was in moderate degradation.
In order to provide accurate model for the forest timber volume estimation,using the data of 245 Cunninghamia lanceolata trees obtained on the standard sampling sites by the forestry table compilation work,both one variable and binary model,as well as multiple variables model based on diameter at breast height (DBH),tree height (H) and crown width (Cw) as independent variables were optimized and constructed.The 11 types of curve model were fitted firstly with one independent variable.And then binary model was established using power function.In the end,the DBH-H-Cw multiple independent variables volume model was established by nonlinear regression estimation method,which was regarded as the best model for the fitted and tested parameters.The results showed that: 1) The power function was regarded as the best model among the 11 types of curve model.2) As far as the determinant coefficient and significant test level were concerned,multiple independent variables model was superior to two independent variables model,and then which was superior to one variable model.The most optimized multiple independent variables model combined of DBH,H and Cw had the determinant coefficient of 0.988,the contrast error of 0.087%,the total error of 0.57%,and the prediction accuracy of 99.40%.3) The most optimized model can drag the maximum loading information of the data obtained from forest timber structure,and provide measurement basis for highly accurate estimation method to the forest volume.
Based on Landsat8 OLI remote sensing imagery and the second class survey data of forest resources,taking Zhenyuan County,Pu'er City,Yunnan Province as the study area,with sampling accuracy (E) of 90% and reliability index (tα) of 95%,the two-stage sampling technique was applied,using AGB per unit area,above-ground accumulation per unit area,seven single bands and five vegetation indices of Simao pine in Zhenyuan County as the sampling markers,so that the overall sampling variance,coefficient of variation,standard error,absolute error,estimation accuracy,AGB estimation value and estimation error of different sampling schemes were analyzed and compared with simple random sampling and systematic sampling to analyze the comprehensive efficiency of different sampling methods applying different sampling marks.The results showed that:1) the comprehensive efficiency of the two-stage sampling was much higher than that of simple sampling and systematic sampling,2) The efficiency of the two-stage sampling based on single band and vegetation indices was generally better than which was based on the 2nd-class survey data,and the best sampling signs of the two-stage sampling efficiency were ARVI and NDVI,and only 154 samples were required for the two vegetation indices,which reduced the sample size by 60% compared with the two-stage sampling based on the 2nd-class survey data,and the precision could reach the highest,which were 97.50% and 97.67%,respectively.The two-stage sampling based on remote sensing factors could significantly improve the sampling efficiency.
The ground fixed sample plot is a basic sampling unit for forest resource monitoring in a large regional scale.The prediction accuracy of ground fixed sample will directly affect the accuracy of the overall regional monitoring results.Based on the sample type,spatial arrangement and size of the sample plot,random sampling method was adopted in a 1 hm2 area plot to verify the optimal sample type of forest resources monitoring in different types of stands by sampling accuracy.The results showed that: 1) The optimal plot area scales for stock monitoring in different stand types were different.When laying ground fixed plots,the plot area and spacing should be determined according to the origin and age group of the stand.2) Under the condition that the sample area was the same,the sampling monitoring accuracy of the single round sample was slightly higher than that of the single square sample,the accumulation sampling monitoring accuracy of the cluster sample was obviously higher than that of the single cluster sample,and the sampling monitoring accuracy of the four-point round cluster sample was slightly higher than that of the square cluster sample.
Based on the database of natural forest resources in Guangdong Province,eight attribute factors of natural forest sub-compartment were selected from it,and an index system for the quality evaluation of natural forest resources was established.The fuzzy comprehensive evaluation method was used to evaluate the quality level of natural forest resources in Guangdong Province,and its correlation was analyzed.The results showed that among the different regions in Guangdong Province,the quality of natural forest resources in northern Guangdong was the best (2.4214),and the evaluation score of natural forest resources in eastern Guangdong was relatively low (2.0416).The comprehensive evaluation values of natural forest resource quality in various regions of the province were ordered as follows: Northern Guangdong Region>Pearl River Delta Region>Western Guangdong Region>Eastern Guangdong Region.The comprehensive evaluation values were sorted according to ecological location: National Nature reserves/ World Natural Heritage sites>important reservoirs>banks of rivers >desertification and serious soil erosion areas>coastal shelter forest base trunk forest belt.The comprehensive evaluation values of natural forest resource quality in Guangdong Province was 2.3818,and the overall evaluation value of each region was higher than that of "medium".The key factors affecting the quality of natural forest resources were the stock volume per hectare,the age group and the mean DBH,and the two indicators with the highest correlation with the comprehensive evaluation results were the degree of closure (coverage) and the age group.
The research took 10 sample plots in Liuxihe Forest Farm in Guangzhou as the object.10 evaluation indexes were selected with the criteria of stand stability,stand spatial structure and stand productivity by using the analytic hierarchy process to comprehensively evaluate the forest quality.The results showed that the overall level of forest quality in Liuxihe Forest Farm was at a good level,with excellent forest quality accounting for 30%,good forest quality accounting for 40%,and medium forest quality accounting for 30%;The weight order of forest quality evaluation criteria layer from large to small was stand productivity (0.593 6),stand stability (0.249 3),and stand spatial structure (0.157 1).The forest quality of Liuxihe Forest Farm can be improved through the transformation of low-quality and inefficient forests and the tending of young and middle-aged forests,the scientific and rational adjustment of forest structure,and the strengthening of early warning and monitoring of forest disasters.
The AHP analytic hierarchy method was used to evaluate the ecological sensitivity of the Yellow River Scenic Area in Zhengzhou from four aspects,including topographic landform,natural environment,scenic resources and human activities.The results showed that the overall ecological sensitivity of the Yellow River Scenic Area in Zhengzhou was mainly medium and high.The area of insensitive area was 2.195 km2,accounting for 8.7%;The area of low-sensitivity area was 6.104 km2,accounting for 24.3%;The area of the middle sensitive area was 6.959 km2,accounting for 27.7%;The area of high-sensitivity area was 6.175km2,accounting for 24.6%;The area of the extremely sensitive area was 3.697km2,accounting for 14.7%.The evaluation results can provide a reference for the ecological protection and high-quality development of the Yellow River Scenic Area in Zhengzhou.
In order to analyze the change of biomass distribution characteristics with plant size of Pinus yunnanensis seedling,taking P.yunnanensis seedlings as the object of study,615 2-year-old seedlings of P.yunnanensis were analyzed by full stem harvesting method.According to the determination of organ biomass,biomass allocation pattern and its change with plant size were analyzed.The results showed that concerning the individual plant level,P.yunnanensis seedling biomass was distributed in the following order: leaves biomass percentage (58.13%)>stem biomass percentage (26.31%)>root biomass percentage (15.57%),the photosynthetic organ biomass percentage (58.13%)>the photosynthetic organ biomass percentage (41.87%),above-ground biomass percentage (84.43%)>under-ground biomass percentage (15.57%),indicating that biomass allocation of P.yunnanensis seedling had trade-offs.Biomass allocations of P.yunnanensis seedling had large fluctuations on the individual plant level.The variation coefficient changed from 6.07% to 60.47%.The linear relationships were existed between root,stem and needle,above-ground part,the photosynthetic organ biomass (P<0.01),which could be used for biomass estimation.The biomass allocation of P.yunnanensis seedling changed with the plant size,and the available power function curve fitted well the relationship between them.When seedlings were little size,biomass allocation tended to be part of above-ground part,and distribution of needle biomass was dominated.In general,biomass allocation of P.yunnanensis seedling had trade-offs,and was subject to the influence of plant size.
The dust fall and forest soil of Pinus sylvestris var.mongolica plantation in the southern Horqin sandy land from 2020 to 2021 were collected and analyzed.The results showed that Pinus sylvestris var.mongolica plantation could play a good role in reducing sand and dust weather,and there was a significant negative correlation between particle deposition and distance from forest edge (P<0.05).The closer to the forest center,the lower the sand content of dust fall would be,and the higher the organic matter and total nitrogen content would be.Affected by dust fall,forest soil nutrients were significantly positively correlated with the distance from the forest edge (P<0.05).The farther from the forest edge,the higher the content of soil organic matter and total nitrogen would be.Pinus sylvestris var.mongolica plantation has played a good role in reducing sand dust and improving soil fertility in Horqin sandy land.
In 2013,24 rectangular plots with the size of 20m×30m were laid in Neilang Township,Youhao,Dahai Forest and Dongfanghong Forestry Bureau of Heilongjiang Province.Among them,12 plots were treated as control plots without tending measures and maintaining natural growth.The other 12 plots were tending plots,and the corresponding forest tending measures were taken as tending plots group.The two groups of plots were retested in 2016.To analyze and evaluate the effects of forest tending measures on the monitoring of comprehensive forest effectiveness and the effects of the same tending measures on the comprehensive forest effectiveness under different site types,the time series horizontal comparison method and the intra-group longitudinal comparison method were used,respectively.The results showed as follows: 1) The average volume growth,average annual carbon sequestration and oxygen release,average annual biomass growth and biodiversity growth values of each tending plot were higher than those of the control plots.2) Under the same tending measures,the tending effects of stands of different site types were quite different.
Daxing'anling Mts.are the most important cold-temperate taiga forests in China.By taking Huzhong National Reserve,as the study objective,we investigated trees,shrubs and herbs by the field plot method,and calculated plant diversity indices,then performed redundancy ordination of their association and found that,Larix gmelinii was the main tree species in the arbor layer,with a relative abundance of 80.39%,followed by Betula platyphylla. The proportion of lingonberry (Vaccinium Vitis-Idaea) was the highest among shrubs,reaching 87.85%.A total of 51 species of herbs layer were found,of which Deyeuxia angustifolia accounted for the largest proportion,reaching 37.85%.Larix gmelinii was the main tree species in the regeneration layer with the relative abundance of 77.94%,and the rest was Betula platyphylla.Redundancy ordination and variance partitioning analysis showed that the independent effect of community structure and shrub layer characteristics contributed the most to the diversity change,and shrub coverage,ground diameter of regeneration layer and shrub density had the closest relationship with plant diversity change,and the protection of plant diversity can be achieved by adjusting the above factors with fully accounting of the impact of other community structure characteristics of arbor,shrub and herbs on species diversity.
We investigated the applicability of fused data in forest resource surveys by fusing backpack LiDAR and airborne LiDAR point cloud data to estimate the single wood factor of eucalyptus trees in four eucalyptus plantations in Wuzhishan City,Hainan Province,with a total of 157 eucalyptus trees. A comparison of the results with the actual sample plots showed that the fused point cloud data had an R2=0.982 and RMSE=0.868cm for the estimation of diameter at breast height,and R2=0.895 and RMSE=2.005m for the estimation of tree height,which was better than that of the high accuracy of the tree obtained using only backpack LiDAR data (R2=0.835 and RMSE=2.458m).This study demonstrated that backpack LiDAR-based point cloud data was more accurate in obtaining single wood diameter at breast height,and that fused point cloud data could improve the estimation of tree height from single backpack point cloud data.
Using near-infrared spectroscopy,64 leaves of P.bournei in the P.bournei Seed Garden of Guanshan Forest Farm in Yongfeng,Jiangxi Province were used as materials,and the nitrogen content of P.bournei leaf samples was determined by the traditional chemical analysis method as a reference value.At the same time,the near-infrared spectrum of the P.bournei leaf powder samples was collected.Using the chemometric software NIRCal,the optimal determination model was established by selecting the modeling method,modeling band,and pre-treatment method.In addition,10 unknown samples were randomly selected to test the model,and the paired sample T test was used to evaluate the model.The results showed that the model established by the Principal Component Regression (PCR) method had the best effect;its related coefficient of calibration (Rc) was 0.912;the Root Mean Square Error (RMSEC) of calibration was 1.098;the related coefficient of validation (Rv) was 0.897;and the Root Mean Square Error of validation(RMSEV) was 1.192.The external verification results showed that the relative deviation between the predicted value and the measured value ranged from 0.070 to 0.705,and the paired sample T-test results showed that the P value was 0.116,greater than 0.05,and there was no significant difference.It can be used for large-scale rapid detection of the nutrient level and high-quality seed selection of P.bournei.
Aiming at the challenges existing in the process of intelligent development of forest and grassland patrol management system,on the basis of the existing patrol management system,a simple,practical,effective and optimized forest and grassland intelligent patrol management system was designed by applying the technical means of forest and grassland grid management,patrol task management,spatio-temporal data analysis and system sharing service.The system is helpful to improve the efficiency of patrols,reduce the burden of grassroots,standardize patrol work,mobilize the participation of member units,and realize grid-based,real-time,and intelligent decision-making management,in order to accelerate the construction of ecological civilization,promote the high-quality development of forest and grassland undertakings.