| At present,the human living environment,peripheral construction and material and spiritual needs are mostly inseparable from forest resources,forest resources and human survival and development are closely related,forest tree accumulation or accumulation is a key indicator of direct response to the status quo of forests.Today,the monitoring of forest resources in China has gone through many periods,at present,mainly rely on a class of surveys in China(continuous inventory of forest resources),a class of surveys conducted every 5 years,to carry out a comprehensive statistical survey of China's forest resources.With the improvement of science and technology,as well as the rapid development of the economy,in order to improve the efficiency of a class of surveys,the sampling scheme is optimized and improved,the main purpose is to save a lot of work,improve work efficiency and facilitate a more concise sampling scheme for future years.The sampling method will be analyzed and made,some provinces in China have diverse topography and uneven distribution of resources,but still use the national unified system sampling method,so that the sample accuracy of the practice has been reduced,this article to carry out a pilot improvement of such cases,the use of a variety of layered sampling schemes and the reduction of the number of samples.For the future of a class of inventory to enhance some efficiency,save money,and improve the accuracy of inventory in some provinces.In this study,Hebei Province and Anhui province were used as research areas to study and explore a new layered scheme for the accumulation and sampling of live wood in the two provinces.An attempt was made to improve the accuracy of forest accumulation data monitoring and the representation of sample samples by using different stratified sampling schemes,and the sample sites of the mesh cloth points sampled by the previous system were used as the monitoring objects in the two provinces,and the multiples were reduced.Reasonable design of different stratification scheme of the survey method to compare the accuracy of the accumulation of live wood,due to the current data time constraints,the study will be the eighth time Forest resources continuous inventory data as the basic data,the accumulation of the monitoring.The article will be layered from the geomorphology,county boundaries,closed degree,respectively,layered into two layers and three layers through the sampling accuracy compared with the previous system sampling accuracy,in order to achieve the optimization effect.The results of stratified sampling of the sampled monitoring objects were shown by the systematic sampling of the sample sites:In this paper,the sampling accuracy of six sampling schemes in Hebei province was more than 90%,the system sampling was 94.33%,and the sampling accuracy of the stratified sampling scheme of geomorphology,county boundaries and closed in the two-laye stratification scheme was:94.33%,94.34%,94.79%,and the three-layer layered scheme was based on the geomorphology.County boundaries,closed degree of layered sampling scheme accumulation sampling accuracy is:94.36%,94.35%,94.89%.The sampling accuracy of six sampling schemes in Anhui Province was more than 90%,the system sampling was 96.08%,and the sampling accuracy of the stratified sampling scheme in the two-layer layered scheme was:96.09%,96.07,96.82%,and the three-layer layered scheme was based on geomorphology,county boundaries andThe sampling accuracy of the layered sampling scheme of closed degree is:96.31%,96.31%and 96.96%,respectively.Three kinds of six kinds of sampling schemes for dynamic wood accumulation all meet the requirements of a class of investigation technology in China,and prove the feasibility of stratified sampling scheme for some provinces with diverse topography and geomorphology in China.In the efficiency analysis,the number of plots of three kinds of six stratified sampling schemes decreased.In Hebei Province,the sampling scheme with closed degree attribute stratification is the best,and when the closed attribute is divided into two layers,the number of samples required is 6962,and the number of sample places required when the closed attribute is divided into three layers is 6728 pieces.When the layered sampling accuracy is reduced to the same as the system sampling accuracy,the number of sample plots required in a hierarchical scheme with a closed degree attribute divided into three layers is the fewest,requiring only 5389 samples,and the efficiency is increased by 1.2 times times.Three types of six stratified sampling schemes in Anhui province.The sampling scheme with closed degree is also the best,when the closed degree is divided into two layers,the number of samples required is 7179,and the number of sample places required when the closed attribute is divided into three layers is 7153 pieces.When the layered sampling accuracy is reduced to the same as the system sampling accuracy,the number of sample plots required in a hierarchical scheme with a closed degree attribute divided into three layers is the fewest,requiring only 4156 sample sites and increasing efficiency by 1.8 times times.To sum up,taking the closed attribute stratification as the optimal stratification scheme,the sampling accuracy is the highest and the sample number of samples is the lowest by dividing the whole into three layers. |
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