A GIS-based analysis on the relationship between the annual available amount and the procurement cost of forest biomass in a mountainous region in Japan

The feasibility of utilization of forest biomass for energy in a mountainous region in Japan is discussed based on analyses with a geographic information system (GIS). In this study, ‘forest biomass’ denotes logging residues, thinned trees, and trees from broad-leaved forests. First, using the GIS, the distribution map of biomass resources was completed, and the topographical information of each sub-compartment was prepared. Second, harvesting and transportation systems were classified into six types by fraction of tree for energy (two types) and by topographical conditions (three types). Equations for cost calculation were developed and included the variables slope, skidding/yarding distance, and transportation distance. Finally, the relationship between the mass and the procurement cost of forest biomass in the region was analyzed. The results show that logging residues (the available amount was 4.035 Gg y⁻¹ on a dry-mass basis) were the least costly followed by broad-leaved forests (20.317 Gg y⁻¹) while thinned trees (27.854 Gg y⁻¹) were the most costly. The analysis may support operational planning, especially the decision of selecting sub-compartments to be felled. For instance, the amount of biomass needed to supply a power-plant covering 24.8% of the regional household need was calculated to 30.106 Gg y⁻¹. This amount of forest biomass could optimally be harvested from sub-compartments whose procurement costs were lower than 108.6 US$ Mg⁻¹.