Keywords:Planted Forest, Forest Health Check Activities, Yahagi River Basin
Planted forests, which occupies 40 percent of the Japanese forest was mostly planted in 1955-70 and is left unmanaged because of a wood import liberalization, a strong yen rate, wood demand decrease, lack of a forestry practitioner. Such forests is dark, consists of tall and thin trees, no undergrowth, a raindrop erosion occur, water holding capacity is weak, and tends to collapse. But no one can grasp correctly by how much percentage such forest exists by the river basin scale including a specialist. A forest volunteer takes the leading part and has begun "Forest Health Check Activity" from 2005 with a researcher in the Yahagi River basin. General citizen, guided by a skillful forest volunteer, enter a mountain, and check the health condition of a planted forest by a scientific and handy method. The data is analyzed by a researcher and shares a result by participants and also proposes for forest administration officers. An implication to the scientist's role in the society and the state of the scientist's participation to a problem solution is considered from an outcome of having a Forest Health Check Activity which is continued and has ended in 2014 for 10 years from 2005.