美国从四十年代就开始观测、试验和研究森林采运作业与水土流失和迳流的变化关系。其研究方法和结果,对我国开展这方面的研究有所助益,兹介绍如下。一、试验流域的自然地理特征和采运的作业方式1976～1978年,美国林务局在西北林业试验站俄勒冈州试验林地,对森林采运作业引起的水土流失和迳流变化进行了小流域的系统试验与研究(表1)。 Since the 1940s, the United States has started to observe, test and study the relationship between the operation of forest harvesting and the erosion and erosion. The research methods and results of this study will be helpful to our country in this aspect. Here is the introduction. First, the natural characteristics of the basin and the operation mode of harvesting In 1976 ~ 1978, the United States Forest Service in the Northwest Forest Experimental Station Oregon experimental forest land, forest mining operation caused by soil erosion and change in the flow of small watershed System testing and research (Table 1).