Abstract
In order to establish the yarding operation system and to spread the efficient thinning yarding operation technique with a mobile tower-yarder, yarding operation efficiency and yarding operation system, yarding operation time in the line thinning yarding operation were investigated. In the line thinning yarding operation by a mobile tower-yarder, the ratio of choking time and lateral yarding time in the main operation time was the highest. The ratio of setting-up time and dismantling time in the accessory operation time was the highest. In the investigation location, an average yarding timber volume of the line thinning operation by a mobile tower-yarder was 5.25㎥ per a day and man. An average cutting and bucking timber volume was 10.5㎥ and 5.25㎥ per a day and man in the logging operation on the basis of the line thinning yarding operation by a mobile tower-yarder. The relationship of lateral wire traction distance and lateral yarding distance to time was showed low significance. But the relationship of yarding distance to time was showed high significance. Therefore, it is necessary to the raise of ability through the education and training of choking man and operator. As the results of the simulation of the line thinning yarding operation by a mobile tower-yarder, the yarding finishing time of 7 line of one block and 1 ha is about 1 day 4 hours and 5 day, respectively. This result is more high efficiency than the logging operation by man power and wood grapple, tractor winch. Therefore, it is necessary to introduce the yarding operation system by a mobile tower-yarder