On Capillary Path Systems In Steep Mountain Areas

摘要

This paper describes a high-density path network in a steep mountain area which supports intensive, high quality forestry in Osaka, Japan. The network, which may be likened to a capillary vessel system, makes it possible to: undertake intensive treatment of forests; effect a selective harvest of small, scattered product volumes; change the harvesting method from cable logging (which requires greater worker skill and results in high costs) to one in which products are removed from the stump area by grapple boom cranes located on roads. This network consists of a series of 2.0m wide paths which run parallel to the contour lines and a steep (but very solid) main road (2.5m wide) connecting the paths. The former are branch lines (rib paths) used primarily for extraction and the latter (which is paved with concrete) is the main line (backbone) used for access to the branch lines. In this network, the maximum gradient is 30%, the maximum height of embankment is 1.4 m, the minimum turning radius is 6 m, road density is 222.94 m/ha, correction-factor of shape V = 1.421, correction factor of real skidding distance ? = 1.215, and the development percentage is 77.9%. Data shows that the correction factors approach 1.0 as the road density is increased, even in mountainous landforms of the type described.