A Simplified Method of Harvesting Willow Crops Cultivated as an Energy Source in Short Rotation Coppices in Small-scale Farmlands

Abstract

Recently, non-food producing farmlands have been increasingly abandoned in Japan. In this paper, we have focused on willow cultivation. Willow can be used as woody biomass (for energy) and can be cultivated in a short rotation coppice production style to effectively utilize abandoned farmlands. A recently published Japanese willow production manual has proposed a method of harvesting in which large machines are used, as is done in Europe and the United States. Therefore, in this study we have proposed a new harvesting method, in which cutting is conducted using a bush cutter (bush cutters are commonly used by farmers and forest labors) and chipping is done using a small machine. We used three indexes, which are (a) workload (manpower/10 a), (b) energy consumption per area (MJ/10 a), (c) energy consumption per yield (MJ/dry-t), (d) input per area (MJ.manpower.10 a) and (e) input per yield (MJ.manpower/dry-t), to evaluate the method. (d) and (e) are original indexes we suggested. From the resulting estimates of workload and energy consumption, it appears that this process of willow crop farming is almost as efficient as large-scale production methods (Hokkaido Regional Development Bureau, 2010), whilst being better suited to Japanese agriculture's socio-economic context.