Supply potential and annual availability of timber and forest biomass resources for energy considering inter-prefectural trade in Tohoku region of Japan

To promote sustainable timber and forest biomass utilization, this study estimated technically feasible and economically viable availability considering forest regenerations. This study focuses on five prefectures, namely, Aomori, Iwate, Miyagi, Akita, and Yamagata, and considers the trade between these prefectures. The data used in this study include forest registration (tree species and site index) and GIS data (information on roads and subcompartment layers) from the prefectures for private and communal forests. Additionally, this study included GIS data (subcompartment layers, including tree species) from the Forestry Agency of Japan for national forests as well as 10-m-grid digital elevation models (DEMs) from the Geographical Survey Institute. As a result, supply potentials of timber and forest biomass resources were estimated at 11,388,960 m³/year and 2,277,792 m³/year. Then, those availabilities were estimated at 1,631,624 m³/year and 326,325 m³/year. Therefore, the rate of availabilities to supply potentials was 14.3%. Since timber production, and wood chip usage from thinned woods and logging residues in 2018 were 4,667,000 m³/year and 889,600 m³/year, rates of timber and forest biomass resource availabilities to those values were 35.0% and 36.7%, respectively. Furthermore, the demand was estimated at 951,740 m³/year from 100,000 m³/year with the generation capacity of 5 MW. The rate of forest biomass resource availability to the demand was 34.2%. The rates were increased to 64.1% with additional regeneration subsidy, 173.3% with thinning subsidy, and 181.5% with both subsidies. Thus, the estimated availability with both subsidies met the demand sufficiently in this region.