Study on reorganization of the Sugi (Cryptomeria japonica) forest working systems in Tohoku district.

本研究旨在探讨东北地区柳杉林木作业系统的重组方式。本研究的结果如下：1)在杉木作业系统中，从单一林处理向混交林处理转变是可取的。2)在传统的单一林作业系统中，有许多造林技术需要改进，如种植面积和组成、终伐年龄、皆伐间伐和间伐等。3)根据净生产率的变化，将林分郁闭度的发展明确地划分为四个不同的阶段。4)流动塔式间伐作业从劳动生产率的角度选择间伐作业，但在成本方面并不可取。行间伐作业对土壤的干扰强度低于选择间伐作业。5)由于林业的长期萧条，宿木林的经营实践主要靠农户劳动力支撑。

This study was investigated so as to present the way of reorganization of the Sugi (Cryptomeria japonica) forest working systems in Tohoku district. The results of this study are as follows.1) In Sugi working system, it is desirable to change itself from the treatment of monoculture forest to the treatment of mixed forest.2) In the traditional working system of monoculture forest, there are many afforestational techniques that should be improved, the method of planting area and composition, final cutting age, cleaning cutting and thinning, and so on.3) Accordingly development of the stand canopy clearly is divided into four different stages on the bases of the changes in the net production rate.4) Row thinning operations by a mobile tower-yader was preferable to select thinning operations in terms of labor productivity, but was not preferable in terms of cost. The intensity of soil disturbance caused by row thinning operations was lower than by select thinning operations.5) Because of the long-term depression of forestry, the Sugi forest management practice is mostly supported by the rural farm household labors.