Abstract
Nine types of forestry machines (16 kinds, 337 examples) were investigated for their applicability to thinning work under typical working conditions. Thirty-four main types of logging systems used in Japan were modeled and classified into patterns based on 9 factors concerning the applicability of forestry machines and system features. The machinery was roughly divided into the vehicle-type forestry machines and the cable-type forestry machines on the boundary of inclination 15-20 deg. Moreover, in areas that are difficult to approach, cable yarders with span of over 1,000m are used. Tower-yarders and other highly mobile machines are used for short distances not exceeding 150m. Pattern analysis was conducted using the quantification method type-3 based on these applicability data and system factors, and logging systems were classified into five groups. The distribution of the systems suggested the involvement of two axes: the first axis showing yarding performance and the second axis showing accessibility. Moreover, the cable type logging systems and the vehicle type logging systems were symmetrically distributed along a diagonal auxiliary line, and systems near the origin (-2.5, -2.5) were relatively simple systems for short wood yarding and those far from the origin were the systems using a yarder with main cable for full tree and tree length log yarding. Thus, an auxiliary line was suggested as a third axis showing mobility. The groups of logging systems can roughly be located and classified by combinations of the coordinate axes, auxiliary line and concentric circles.
