Studies on information system for watershed forest management (III) : A decision support system to long rotation planning for Karamatsu stands.

Abstract

The purpose of this paper is to propose a decision support system using- an information system for watershed forest management, which provides more practical information on long rotation forest planning in the Tenryu River watershed in Hase Village, Nagano Prefecture. First, GIS was used to divide the planning area into 4 working blocks, one each for large log production, middle log production, small log production and ecological conservation, based on site quality, locality and log demand. Next, the growth and the volume of yield and utilization were predicted for various thinning patterns and felling age by a simulation model using a system yield table for karamatsu(Larix Kaempferi) even-aged stands. The results were as follows: 1) Low thinning is the most suitable method. 2) Thinning is necessary every 10 or 15 years. 3) The rotation in maximum final mean annual increment of yield volume is about 50 years. 4) The rotation in maximum final mean annual increment of utilizing volume is about 50 years for I and II site classes, about 60 years for III site class. Finally, the best felling ages were judged to be about 70 years for large and middle log production, and 60 years for small log production.