Forest Management Based on Site Suitability: A Case Study of Odai Town, Mie Prefecture, Japan

Abstract

Increase in degraded plantation forests in Japan requires an integrated management system that enhances the multiple-use of forests to achieve sustainable forest management. This paper introduces the steps taken in Odai town in Mie Prefecture, Japan, to establish a forest management regime map by evaluating the site suitability for forestry. Site suitability was evaluated from two aspects: the natural site conditions and the relationship among site conditions, growth, and insect damage by Anaglyptus subfasciatus Pic. in Cryptomeria japonica D. Don and Chamaecyparis obtusa Sieb. et Zucc. forests. By analyzing the relationship among site conditions, growth, and insect damage based on field data obtained in plantation forests, a growth evaluation map and insect damage evaluation map were developed. Based on the natural forest investigation, natural site condition maps for C. japonica and C. obtusa were established. Furthermore, by integrating these evaluation maps with the forest road maps showing the accessibility to the forest, the forest management regime for whole of the plantation area of Odai town was established. The forest management regime map indicates sites suitable for long-rotation forestry and short-rotation forestry, and potential sites for short-rotation forestry. Sites more suitable for conversion to broadleaved forests are also identified. Based on the forest management regime map, different forest operations have begun to be implemented at each evaluated area. For sites suitable for long rotation, thinning is implemented for inferior trees and will be repeated as the trees approach the age for cutting (more than 100 years). Thinning is also conducted for the sites suitable for short rotation. However, these will be cut down more rapidly as the trees reach the age for cutting (50 years). At sites evaluated as being more suitable for conversion to broadleaved forests, clear-cutting in a small area is conducted and about 20 broadleaved species are planted in an area of 80–120 m2 protected by deer fences. As these measures have just begun, their effect on enhancing sustainable forest management is still being monitored. Notably, the people implementing these measures are proud of their task and work actively, which might be the most important driving force to solve the problem of plantation forest abandonment and to enhance sustainable forest management in Japan.