Participants’ motives constitute a factor that highly impacts continuity and cooperation in forest volunteer activities. To sustain the social mechanism of voluntary activity, it is necessary to clarify the structure of motives for activities. The purpose of this study is to focus on forest volunteer organizations and members who conduct volunteer activities mainly in the Minoh National Forest in Osaka Prefecture, and to clarify the structure of the motives for their activity. Based on a working hypothesis setting the motives, we established a questionnaire and obtained answers from 105 members from 10 groups. Principal component analysis resulted in 6 principal components of the motives. Using indices based on the combined score of the principal components, we analyzed each group’s motives’ general direction, the homogeneity within the group, common elements with other groups they cooperated with, and other factors, and thus clarified the structure of motives.
