Satoyama forests have been used and managed by farmers for getting materials. But from 1960s, Satoyama forests in Japan were changing their structures gradually because they stopped usage and managements. One of the reasons is reduction and aging of forest workers. According to the national census, Ministry of Internal Affairs and Communications in 2011, the number of forest workers decreased about one third for 20 years from 1985 to 2005. The rate of over 65 years old is 25.53% in 2005. At the present, the companies which perform forest management as CSR (Corporate Social Responsibility) activities are increasing. We have two questions. Why do companies perform forest management? What kind of influence on the structure of forests does occur by forest managements? Then, we will propose more effective forest managements for companies’ CRS performance by these two matters. The research sites are 3 locations in Hiroshima. These sites are managed forest by companies as CSR activities. The result of vegetation survey showed that the structure of forests is difference between managed forests and non-managed forests. For example, the coverage of sub tree and shrub layer of managed forests is less than that of non-managed forests. It means that sunlight fully penetrates on forest floor. In short, the light condition in managed forests is better than non-managed forests.