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1973年,在南、北方进行的全国森林资源清查试点中,都采用了以1:5万地形图做系统抽样调查的方法。现以北方试点的材料为主,将具体做法简介如下: 此方案是在1:5万地形图上系统布置必要数量的样地,在现地准确确定样地位置,在样地上进行测树调查并记载样地所属类型。根据样地材料推算全局森林总蓄积和各类土地面积、蓄积。为了今后能正确掌握森林资源变化情况,将所设样地予以固定,以便建立森林资源连续清查体系。
In 1973, a systematic sample survey of 1: 500 topographic maps was used in national forest inventory surveys conducted in the South and North. Now the materials of the pilot in the north are mainly introduced as follows: The program is to systematically arrange the necessary number of plots on the 1: 50000 topographic map, accurately determine the location of the plots on the spot, and conduct tree surveys on the plots And record the sample type. Calculate the total global forest total area and all kinds of land area according to the site material and accumulate. In order to correctly grasp the changes in the forest resources in the future, the sample sites to be fixed in order to establish a continuous forest inventory system.