Abstract
Consistent clearcutting and reforestation operations are increasing in Japan. It is expected that the reuse of logging machines after clearcutting processes for the purpose of site preparation would result in cost reduction and work efficiency improvement. In the present study, we compared the productivities and costs of manpower site preparation with those of mechanical site preparation using a bucket excavator and grapple loader. The study was conducted at four clearcutting sites at Nagano, Japan having gentle to medium slopes. The results demonstrated that the mechanical site preparation increased labor productivities to the tune of 2–12 times and decreased cost up to 14%–90% in comparison with manpower. It was also noticed that the volume of stacked branches and short logs affected both cost as well as productivity of the mechanical site preparation. Further, both machines greatly reduced operation costs when the stacked volume was small. Contrarily, no significant effects on cost reduction were observed when the stacked volume was large. Multiple regression equations were developed based on the relationships between the angles of worksite slopes and stacked volumes. Moreover, the relationship between the productivities of bucket excavator and grapple loader also contributed toward the regression equation. The results clearly demonstrated the feasibility of estimating the bucket excavator’s site preparation productivities prior to clearcutting, by inputting the stack volume amounts. The above method considered the wood condition before cutting and the worksite slope angles.
