By virtue of the "Forests are lovers of the sea tree-planting ceremony" that started in 1989, 30,000 broad-leaved trees of 50 species have been planted in the upper reaches of the Okawa River, which runs into Kesennuma Bay. However, our activities not only aim at the creation of upland and marine forests, but the thought that the cultivation of mental forests is the most important thing. I would like to introduce activities for the cultivation of children's mental forests through a hands-on learning classroom.