Research On The Optimization Design Of Integrated Monitoring System Of Forest Resources

The national forest resources monitoring system is the main monitoring technology to obtain the dynamic change information of national forest resources.The timeliness,accuracy,depth and breadth of forest resource monitoring data will affect the formulation of long-term development policy of forestry.The international forest resources monitoring system has been developed into a multi-resource and multi-objective annual comprehensive monitoring system at present.In contrast,China's national forest resources continuous inventory system has some shortcomings.Firstly,the spatial information reflection ability is weak by using a single square sample plot as a fixed sample plot on the ground,thus affecting the accuracy of monitoring data.Secondly,the timeliness of monitoring data is low,as the forest resources monitoring report is produced every five years.Thirdly,there is a problem of two sets in one area:the sampling scheme of the system was designed with the province as the overall plan.The monitoring data could not be implemented at the city and county level,and it was independently operated with the forest resources planning and design survey.Fourth,forest resources monitoring content is relatively single,and the monitoring indicators are mainly focused on forest volume monitoring.Thus,in order to optimize China's forest resources monitoring system,improve the accuracy of monitoring data,and achieve multi-objective annual comprehensive monitoring.This paper takes Baoding city as an example to carry out research from the following four aspects:1.To explore the optimal site type for forest resource monitoring in different stand types based on the type of plot,spatial arrangement and scale of plot;2.Time series two-phase sampling method is adopted to design three annual sampling schemes:random,systematic and stratified,and The optimal sampling scheme for annual monitoring of forest resources is verified by simulated data;3.To used The nonlinear exponential model to construct the accumulative estimation model for the tree groups and Update the information of all the small classes in Baoding through the inversion of the prediction model,this to realize the integrated monitoring of city and county accumulations;4.On the basis of the existing monitoring index system in China and the current situation of the development of foreign index system,the monitoring index is enriched in six monitoring contents:basic information of stand,forest health,forest soil,forest biomass,forest biodiversity and forest management.The main research results are as follows:(1)The estimation accuracy of cluster sample plot to stand accumulation sampling is obviously higher than square sample plot,and the four-point circular cluster sample plot is slightly higher than square matrix sample plot with the same area scale.(2)Forest volume monitoring was carried out in different types(origin and age groups)of stands,and the optimal sample size information was different.For the sample land area:when carrying out storage quantity monitoring in natural forest,the optimal sample land area depends on age group.The optimal sample plot area in the young forest was 841m~2,the optimal sample plot area in the middle age was 729m~2,and the optimal sample plot area in the near mature forest was 625m~2.But the optimal sample plots of different age groups in the artificial forest had the same size,all of which were 625m~2.For sub-sample spacing in the mass sample plots,the optimal spacing scheme for mass sample plots monitoring in young and mid-age forests were 14m,and the optimal spacing scheme were 10m in the near-mature forests.(3)Random,systematic and stratified annual sampling schemes,which designed by two phase regression sampling method,were used to carry out accumulative annual simulation monitoring for baoding city for two consecutive monitoring years.The sampling monitoring accuracy is above 90%.Those were satisfied the requirements of the technical regulations on continuous inventory of national forest resources that the sampling accuracy of standing stock should be more than 90%and also verified the feasibility of the annual monitoring scheme.(4).By comparing and analyzing the accumulation sampling precision of three extraction schemes,it can be determined that best sampling effect were stratified extraction scheme(stratified according to the terrain)is adopted for forest accumulation annual monitoring in two-phase regression sampling.The accumulative sampling accuracy of two consecutive monitoring years was 96.94%and 98.01%,respectively.(5)The statistical results of the model(R2,SEE,TRE,MSE,MPE,MPSE)for the estimation of stock in 7 species groups were better,indicating that the model had a good prediction ability.Based on the estimation model of forest accumulation,the error between forest accumulation and annual sampling monitoring value in Baoding city is only 8.94%.(6)By establishing a set of forest,forest health basic information,forest biomass,biodiversity,soil,forest management 6 monitoring content of multi-objective and utilization of forest resources comprehensive monitoring index system,it could provide reference for China's future research and construction of forest resource monitoring index systemThis study based on the shortcomings of the current continuous inventory system of forest resources in China,carried out optimization research from multiple perspectives,it can provide theoretical support and method reference for the optimization reform of forest resources monitoring system in China.