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在我国一些省(区)编写的森林调查技术规定(或细则)中,对于幼龄林的蓄积量调查,都有内容基本相同的规定:凡林分平均胸径<5.0cm的,不进行蓄积量调查;林分平均胸径≥5.0cm的,按蓄积量调查的有关规定,调查林分中≥5.0cm的立木蓄积量。执行这一规定的正确方法,无疑应包含以下两个步骤: (1)首先必须认真地进行目测调查,确定出全林分立木(含<5.0cm的立木)的林分平均胸径和平均树高值,作为是否需要进行蓄积量调查的判断依据。显然,所确定的平均胸径和树高值,是真正代表小班全林分平均水平的特征值,应填写在小班调查卡片的相应栏目内,作为确定小班经营措施和建档管理的基本依据。 (2)当目测调查所确定的林分平均胸径为≥5.0cm时,再按有关规定对林分中≥
In the technical specifications (or detailed rules) of forest surveying written by some provinces (regions) in our country, there are basically the same contents in surveying the storage volume of young forest: if the average diameter at breast height is less than 5.0cm, the storage volume Investigation; average diameter of the forest ≥5.0cm, according to the relevant provisions of the investigation of stock volume, the investigation of stand volume ≥5.0cm stand volume. The correct method of implementing this provision will undoubtedly include the following two steps: (1) A visual survey must first be conducted carefully to determine the mean DBH and mean tree height of stand-stand (stand <5.0 cm) Value, as a basis for the need to determine the volume of the investigation. Obviously, the average DBH value and tree height value are the eigenvalues that truly represent the average level of the entire stands of small classes and should be filled in the corresponding sections of the small-scale survey cards as the basic basis for determining the management measures and file management for small classes. (2) When the average diameter at breast height determined by the visual inspection is ≥5.0cm, then according to relevant regulations,