Abstract
In order to reduce harvesting costs of forest biomass resources, a new carriage for turn back yarding system is examined. The new carriage for turn back yardign system has two carriages with loading equipments. This yarding system could reduce yarding time to about half. When yarding speed and setup time assumed to be increase by 1.5 times, the estimated yarding cost of a tower yarder with the new carriage is less than that of a tower yarder over 200 m at thinning and 80 m at clearcutting. When this yarding system as well as swing yarders which have been widely spread out in Japan recently, are applied to a model area, harvesting costs reduced 16,706 yen/ton to 14,178 yen/ton. Subsequently, the electricity cost of the direct combustion power generation with 5 MW reduced 21.9 yen/kWh to 20.3 yen/kWh.
