以数理统计为理论基础的抽样调查方法,已在一、二类调查中被广泛采用,在伐区调查中也正在总结推广.但就从二类调查来说,其成果多半是通过航空象片、地形图,又通过大量的外业调查而得的,因此,这类第一手材料是比较可靠的.然而,二类调查的蓄积量精度只落实到林班,其精度也仅是理论精度,过去二类调查资源数字在统计过程中,小班资源数字一般是层平均数,也有以林班抽样蓄积作控制,修正小班目测蓄积的.这与总体设计、伐区作业设计对资源数字应着重落实于小班(伐区)的要求有一定出入.所以,过去二类调查的资源部分只是为编制长远规划提供了依据,满足于计划部门使用,而在伐区调查时,由于两者调查的内容各有侧重,区划依据不一,往往要重复进行确定小班(伐区)面积调查蓄积量. Based on mathematical statistics as the basis of the sample survey method, has been widely used in one or two types of surveys, surveys are also being summarized in the cutting area to promote.But from the second survey, the results are mostly through the aerial photo Topographic maps, and a large number of field surveys, the first-hand materials of this type are more reliable, however, the precision of the stock volume in the second-type survey is only implemented in the forest classes and the accuracy is only theoretical accuracy , The past two types of survey resources figures in the statistical process, the average number of small-scale resources is the average number of layers, but also to control the sampling and accumulation of forest classes, amendments to the small class of visual accumulation, with the overall design, cutting operations design should focus on the number of resources Therefore, the resources of the past two types of surveys provide only the basis for the preparation of long-term planning and are used by the planning departments. However, in the investigation of the cutting areas, the contents of the surveys of the two areas Each has its own focus and its basis is different. It is often necessary to repeat the process of determining the volume of surveyed small-scale (cutting-area) area.