The Kunisaki Peninsula has many reservoirs, from Mount Futago (721 meters) in the center to the coast. There are some reservoirs along the mountain slope that line up vertically. Each of these connects to a water channel, and when there isn’t enough water in a reservoir downstream, water is released from upstream.

　Water is essential for agriculture. Shaped like a flattened umbrella, this peninsula has steep terrain and sloped rivers. The distance to the coast is short, and rain water can run off into the sea without sufficiently hydrating the basin. Compared to other areas, there is not enough water to use in the fields. Regardless of whether rainfall is heavy or light, without reservoirs to store rainwater, grain cultivation would be unthinkable. The reservoirs are the fruits of the wisdom and effort of the people who live the life of agriculture and have had to face the nature.

　Around the reservoirs sprawl forests of sawtooth oak. Often found in woodlands south of the main island, these tall deciduous trees are used for firewood and coal. They were essential sources of energy for living until just half a century ago.

　Sawtooth oak is felled and used to cultivate shiitake mushrooms. Their growth is fast, and just 15 years after felling they are back to their original size. Sawtooth oak is used with the cycle of logging and growing so the trees do not go extinct. Shiitake mushrooms are grown according to the rhythm of nature.

　The reservoirs, sawtooth oak forests, and the agriculture and forestry practices that make use of them have made this a Globally Important Agricultural Heritage System. This is the Kunisaki Peninsula Usa Integrated Forestry, Agriculture, and Fisheries System. The designated area is 1,323.75 square kilometers and includes four cities, one town, and one village in the Kunisaki Peninsula and the city of Usa area. This region has supported the Buddhist and Shinto culture of Usa Jingu Shrine and Rokugou Manzan since the ancient times.

　Globally Important Agricultural Heritage Systems are traditional agricultural and richly diverse environments with rural agriculture or landscapes selected for preservation and protection by the UN Food and Agriculture Organization. In Japan, there are several including “Sado Island Agriculture in Harmony with Endangered Japanese Crested Ibis” and “Managing Aso Grasslands for Sustainable Agriculture”.

　For the Globally Important Agricultural Heritage System in Usa and Kunisaki Peninsula, the word “system” has huge significance. This system is deeply tied with the sawtooth oak forest, that is, with the woodlands. Sawtooth oak forests are firmly rooted, improving water holding capacity of the soil and leading water to the reservoirs. Ultimately, this water hydrates the fields then flows to the sea, containing nutrients from the soil to enrich the sea.

　Looking at the bigger picture, greenery, water, and earth are connected like a chain through grain and shiitake mushroom cultivation using sawtooth oak forests and reservoirs. This is what sustainable agriculture, forestry, and fisheries created by humans look like.