Development of a thinning system with a medium-range tower yarder introduced from Europe : Productivity of uphill-lateral yarding(<SPECIAL ISSUE>Tools and machines for logging)

Abstract

This study aimed to develop an operational system for thinning using a medium-range tower yarder introduced from Europe. To that end, the productivity of thinning operations was researched, and the uphill-lateral yarding operation was analyzed in this report. The uphill-lateral yarding time did not have a clear relationship with the loading volume, and had a high correlation with the lateral yarding distance, thus a prediction relation of the productivity for uphill lateral yarding was able to derive. On the mean yarding distance of 156.6 m, the mean lateral yarding distance of 25.7 and the mean loading volume of 0.66 m3 in this research area, the whole productivity of uphill-lateral yarding was 6.2 m3/hour, which was predicted 1.8 times higher than the existing similar tower yarder. It is clear that this newly-introduced tower yarder could be expected to get the higher productivity in the forest condition in Japan.