Abstract
A cable logging method with collector rigging was investigated. The method is a variation of the Endless-Tyler method in which added blocks regulate the track of the haul-back line. The logged area was 2.25ha of a 43-year-old Hinoki stand (thinning rate: 33% by volume). The span of the cable system was 500m. A processor was used. The productivity of the logging operation was 3.2m^3/man-day (six and a half worked hours per day). The cost of logging without rigging was 9.3 thousand yen/m^3 and the cost with rigging was 17.2 thousand yen/m^3. The rigging cost could be reduced to 3.1 thousand yen/m^3 if the adjacent area of 3.75ha is included in the logging area. The cost balance was positive with income from saw logs (10.0 thousand yen/m^3), residual logs (2.2 thousand yen/m^3), and with subsidies for thinning. A simulation revealed that reducing the unhooking operation time would reduce the cost, and that the total cost could be reduced by 10 to 20% if the carriage traveling time was shortened by up to 25% by improving the winch (investment cost of 10 million yen). The residual stand damage was 7.8% (rate of damaged trees to total remaining trees), which was remarkably low compared to using other vehicle-type logging methods (ca. 20%). However, some trees were severely damaged when logged trees moved backward and forward a great deal when they ware pulled laterally.
