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森林资源数字是编制林业生产计划的重要依据,而森林资源又随着时间的推移在不断地消长变化。虽然森林资源清查是取得资源数字的主要手段,但这项工作由于人力、财力的限制不可能频繁地进行。那么,怎样合理的估测调查间隔期中的资源数字呢?这就要取决于生长量的调查。知道了森林的生长率和枯损率就很容易以资源调查中相应的数据为基础,利用复利公式推算出某一时期的资源数字。生长量调查的关键问题:一是外业调查中样本的抽取是否合理;二是内业计算中生长率整列公式的选择是否得当。本文讨论的重点是生长率整列公式的形式问题。过去,被广泛采用的生长率整列公式的类型为:
The number of forest resources is an important basis for compiling forestry production plans, and forest resources are continuously changing and changing over time. Although forest inventory is the main means of obtaining the resources figure, this work can not be carried out frequently due to the restriction of manpower and financial resources. So, how to reasonably estimate the number of resources in the survey interval? It depends on the growth of the survey. Knowing the growth rate and the rate of loss of forests can easily be calculated on the basis of the corresponding data from the resource survey by using the compound formula to calculate the number of resources for a given period. The key questions of the growth survey are: First, whether the sample extraction in the field survey is reasonable or not; and secondly, whether the choice of the formula for the growth rate in the calculation of the industry is appropriate. The focus of this article is the formality of the formula for growth rates. In the past, the widely used growth rate formula for the entire column was: