各种防护林和四旁树是不可忽视的森林资源,然而对这类林种的调查乃是我国森林资源清查的新课题。江苏省已在这方面做了不少工作,并取得可喜成绩。现介绍两篇有关文章,以供参考。本文所谈“线抽样”并非通常角规调查中的“线抽样”,望予区别。 All kinds of shelterbelts and trees on the four sides are not negligible forest resources, however, the investigation of such forest species is a new issue of forest inventory in our country. Jiangsu Province has done a great deal of work in this regard and has achieved gratifying results. Now introduce two related articles, for reference. The “line sampling” mentioned in this article is not the “line sampling” in the surveying of the goniometer.