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四旁树木是平原防护林体系的一个重要组成部分,无论是株数、蓄积,还是覆盖面积,都占有很大的比重。如邳县1981年调查,全县树木总株数4,019万株,其中四旁树2,015万株,占50.1％;全县立木蓄积92.7万立方米,其中四旁树蓄积74.4万立方米,占80.3％,全县林木覆盖面积43.97万亩,其中四旁树覆盖面积26.4万亩,占60％。林木覆盖率是林木资源通用可比指标,四旁树木的覆盖面积是平原地区林木覆盖率的主要成分。所以,进行四旁树覆盖面积的调查,对掌握林木资源、摸清现有林木覆盖状况,从而准确地进行林木覆盖率的规划,正确指导林业生产,具有重要意义。怎样进行四旁树覆盖面积的调查,我们从1981年开始作了一点尝试,现将具体做法及其结果汇报于下。 一、二种调查方法的比较 先在红旗乡寨墩村进行试点,对四旁树覆盖面积的调查,采用了二种方法。 (一)面积实测法 首先将四旁树划为农田林网(不够片林标准的林木)、散生树木、自留地树木和村庄树木四种类型,分别
Four sides of the trees is an important part of the plain shelter forest system, regardless of the number of trees, accumulation, or coverage, both occupy a large proportion. For example, in Lixian County in 1981, the total number of trees in the county was 40.19 million, of which 20.15 million were on four sides, accounting for 50.1% of the total; and the whole county had 927,000 cubic meters of trees, of which 744,000 cubic meters were occupied by four sides, accounting for 80.3% of the total County forest cover an area of 439700 acres, of which four sides of the tree covers an area of 264000 mu, accounting for 60%. Forest cover is a common and comparable indicator of forest resources, and the coverage of trees on four sides is the main component of forest cover in the plain. Therefore, it is of great significance to investigate the coverage of trees on four sides, to master the forest resources, to find out the existing forest cover, to plan the forest coverage accurately and to guide the forestry production correctly. How to conduct a survey on the coverage area of trees on the four sides, we have made some attempts since 1981, and we now report on the specific practices and their results. First, the comparison of the two survey methods First in the red flag village Walled Pier pilot, the four sides of the tree cover area survey, using two methods. (A) area measurement method First of all four sides of the tree planted for the farmland forest network (not enough forest standard forest), scattered trees, privately-owned trees and village trees, four types, respectively