In 1995, the Fudosawa Water Source Forest was selected as one of the 100 Best Water Source Forests in Japan.

It is an excellent forest that prevents water from drying up and prevents flooding, has been cherished by people since ancient times, and as such has a long and deep history of physical and spiritual ties with the people of the basin.

The headwater forest originates from Numajiri in Dokkonuma pond, the main stream of Fudosawa, and the northern slopes of Zao. It is a water source forest that merges with many streams to reach Mamigasaki River in Yamagata City.