基于群团抽样技术的森林资源监测方案研究

Forest Resource Monitoring Based on Cluster Sampling Techniques

为探索适合我国森林资源实情的监测抽样新技术,借鉴美国森林资源年度监测技术方案,以北京市延庆区为研究区,进行森林蓄积量群团抽样试验研究。首先在美国森林资源年度监测体系基础上,根据所选研究区域的森林资源分布状况,确定适宜的正六边形抽样框架尺度以及抽样比例,在抽选的正六边形抽样框架内布设圆形群团样地并进行实地调查,从而获取研究区当年森林蓄积量信息。结果表明,采用正六边形抽样框架在北京市延庆区开展森林资源年度监测的适宜面积为2 338 hm^2,边长为3 000 m,最适抽样比例为66%;根据所设计的群团抽样方案进行实地调查获取延庆区2016年的森林蓄积量为16. 6 m3/hm^2,抽样调查精度达85. 4%,符合《国家森林资源连续清查技术规定》对抽样精度的要求,验证了基于圆形群团样地在我国区、县级尺度上开展森林资源监测的可行性。

In order to explore the new monitoring sampling technology suitable for the situation of forest resources in China,based on the annual monitoring technology of forest resources in the United States,the annual monitoring of forest volume was researched in Yanqing District,Beijing.Firstly,according to the actual situation of forest resource distribution in research area and based on the design of American annual monitoring system of forest resources,some optimization and improvement in the size of hexagonal sampling frame and sampling rate were done,and a system sampling scheme for annual forest inventory monitoring was designed.The result showed that using the positive hexagonal sampling frame to do annual monitoring of forest resources can receive an optimal scale area,an optimal side length and an optimal sampling fraction,and the amount was 2 338 hm 2,3 000 m and 66%,respectively.According to the systematic sampling scheme,and combining with field investigation,the volume amount received in Yanqing was 16.6 m^3/hm^2,the sampling monitoring accuracy was 85.4%,which was all conformity with NFI Technical Regulations.Therefore,the feasibility of the proposed forest resource monitoring scheme based on cluster sampling technology in China was verified.The main points of cluster sampling technology and the method of forest accumulation amount output based on circular cluster were introduced in detail.The research result can provide reference for the optimization and improvement of the national forest resources continuous inventory system and the field sampling survey technology.