2021 Volume 103 Issue 6 Pages 443-448
The yield percentage by tree species was estimated and the effect on the amount of wood biomass resources available was examined. In order to estimate the yield percentage of larch, cypress, cedar, and red pine by species, the results of logging operations in Nagano Prefecture were used to determine the amount of timber cut and sold, and to estimate the yield of lumber produced. As a result, the yield percentage of all tree species in clear-cutting was lower than the conventional value, and in thinning, it was higher than the conventional value for all tree species except red pine. In addition, by yarding system, the value for vehicle-based yarding was higher than that for overhead wire-based yarding. Using these results, we estimated the amount of wood biomass resources available when the yield percentage was taken into account for each tree species and when the percentage was assumed to be constant as in the conventional method. The results showed that the availability of larch, cypress, and cedar increased, while that of red pine decreased, compared to the estimation by the conventional method. The results suggest that it is important to accurately estimate the yield percentage.
