散居集落の景観保全に向けた屋敷林における住民意識及びその分布・植栽形態と景観施策に関する研究―岩手県胆沢町を事例として―

Abstract

Isawa is a town in the Iwate prefecture, famous for its homestead woodlands which surround dispersed settlements. Despite its renown, it has been decreasing rapidly. A study was conducted on the following. The structures of the homestead woodlands, the residents' awareness of the woodlands and the policy of the local government to conserve the woodlands.In this district, the woodlands are primarily located in the northern and western sides of the houses to protect them from the wind and snow. The predominant tree species are the evergreen conifers such as Cryptomeria japonica. The structures of the woodlands were divided into four categories.Type I: The numbers of trees are less and usually planted in a single row where the low branches are pruned frequently.Type II: The numbers of trees are more than type I, and planted closely in multiple rows.Type II includes type II-1, where tree's height is higher than the roof, and type II-2, where tree's height is lower.The species of trees are less and usually limited to conifers as mentioned in Type I and II.Type III: The trees are planted in eastern side, in addition to the northern and western sides. Here, several broadleaved species of trees have been planted in addition to the conifers.There are a variety of trees, which include several broadleaved species, in addition to the conifers. The layer of trees between the arbor and shrub layers was missing. To increase the volume of homestead woodlands, the planting pattern determined by our investigations may be utilized as a reference. In addition, it may easily be promoted by seeking financial assistance from an organization. On the other hand, homesteads, which do not require such financial assistance, the maintenance and management options that would not destroy the landscape's function, were suggested within the tolerance level.Most residents are proud of the homestead woodlands. They are of the view that the woodlands have great value in making up the original landscape and have an addition role in the protection of houses from disasters. However, the younger generation displayed less interest than the elder generation.The town's government has been providing subsidies for the plantation of homestead woodlands, since 1996. The above categories indicate the values of homestead woodlands. These indexes may be useful in promoting the subsidy system.The homestead woodlands are decreasing rapidly throughout Japan. It is very important to raise this awareness and also improve the subsidy system. Furthermore, the total strategies to conserve the woodlands by land use and landscape regulations are still not in place. The local government must seriously consider these.