Satoyama


 * For the sumo wrestler Satoyama, see Satoyama Kosaku

Satoyama (里山) is a Japanese term applied to the border zone or area between mountain foothills and arable flat land. Literally, sato (里) means arable and livable land or home land, and yama (山) means mountain. Satoyama, which have been developed through centuries of small scale agricultural and forestry use, also promise biodiversity if properly maintained by human activities.

The concept of satoyama has several definitions. The first definition is the management of forests through local agricultural communities. During the Edo era, young and fallen leaves were gathered from community forests to use as fertilizer in wet rice paddy fields. Villagers also used wood for construction, cooking and heating. More recently, satoyama has been defined not only as mixed community forests, but also as entire landscapes that are used for agriculture. According to this definition, satoyama contains a mosaic of mixed forests, rice paddy fields, dry rice fields, grasslands, streams, ponds, and reservoirs for irrigation. Farmers use the grasslands to feed horses and cattle. Streams, ponds, and reservoirs play an important role in adjusting water levels of paddy fields and farming fish as a food source.

Human relationship with Satoyama
Human Population, Ownership, Landuse

Population decline in villages is considered a significant driving factor in the disappearance of satoyama from Japanese mountains. The depopulation of villages has occurred because of recent economic events from 1955 to 1975, which have created significant social and economic gaps between people in modern cities and mountain villages. Moreover, natural conditions such as steep slopes, landslides and snowfall have led people to stay away from satoyama. Regarding ownership, inhabitants in satoyama determined the shared ownership of common forests near their village in the beginning of 19th century. These forests were logged for economic considerations and the construction of houses. Because people have cut down forests near their village, today we often see old-growth forests, including beech in high elevations far from a village. Inhabitants use the wood from their private forests and conifer plantations for fuel. By the 1960s, satoyama was utilized as rice fields, plowed fields, shifting cultivation, grasslands, thatch fields, Secondary forests for fuel, and giant bamboo forests.

Biodiversity in Satoyama
Various habitat types for wildlife have been provided by mixed satoyama landscape as a result of Japanese traditional agricultural system what also facilitates the movement of wildlife between a variety of habitats. The migration of wild animals can occur among the ponds, rice paddy fields, grasslands, forests, and also from one village to another. Because of these ecosystems, a rich biodiversity in the Japanese rural area has been maintained. Ponds, reservoirs, and streams in particular play a significant role in the survival of water dependent species such as dragonflies, and fireflies. In the early stages of their life cycle, they spend most of their time in water. Through maintaining a mixture of successional stages by the agricultural activities and the management of satoyama, the preservation and promotion of biodiversity are facilitated. For instance, Japanese oaks and Japanese chestnut oaks are planted by farmers to maintain deciduous broad-leaf trees. Succession to dense and dark laurel forest is prevented by farmers that cut down these trees for firewood and charcoal every 15 to 20 years. Most plant and animal species are able to live in these deciduous forests because of traditional management practices. Therefore, much more wildlife can be supported by well managed forests than dark unmanaged laurel forests.

Causalities of the disappearing Satoyama


Satoyama has been disappearing due to the drastic shift in natural resources from charcoal and firewood to oil and the change from compost to chemical fertilizer. Also, the problem of aging in Japanese society can cause the disappearance of satoyama because there are fewer people who can work in satoyama which are considered as intermediate disturbance on forests such as harvesting trees for timber and charcoal, cutting shrubs for firewood and collecting litter as compost. These human impacts can help the success of the forest occur. As the final causality of the disappearing of satoyama, pine dominated secondary forests in satoyama were increasingly destroyed since pine wilt disease devastated pine forests in the 1970s.

Conservation of Satoyama
Throughout the 80s and 90s, the satoyama conservation movement was implemented in Japan because people realized that satoyama were needed to maintain healthy ecosystems. Currently, there are more than 500 environmental groups that work for the conservation of satoyama. The main challenge for satoyama conservation today is that depopulation in satoyama has prevented the harvest of old growth trees which can support less biodiversity in satoyama than secondary growth forests. To deal with this problem, volunteers from the groups monitor satoyama to determine when to harvest trees appropriately. They also educate young people to teach how satoyama is important historically and ecologically and how the conservation of satoyama should be managed. Because of their efforts, satoyama has become more prevalent in Japanese landscapes.