No abstract

No abstract

To utilize timber and forest biomass resources for bioenergy, technically feasible and economically viable timber and forest biomass resources should be estimated accurately considering their long-term availability. This study focuses on five prefectures, namely, Aomori, Iwate, Miyagi, Akita, and Yamagata, and considers trade between these prefectures. The annual availability of timber and forest biomass resources, such as small-diameter or defect stem logs, rather than logging residues in Japan was estimated as supply potential from profitable forests where expected revenues surpassed all costs, from planting to final harvest. As a result, the supply potential and annual availability of timber were estimated at 11,388,960 m3/year and 1,631,624 m3/year, whereas those of forest biomass resources were estimated at 2,277,792 m3/year and 326,325 m3/year, respectively. Therefore, the rate of annual availability to supply potential 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, the rates of annual availability for timber and forest biomass resources 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 a generation capacity of 5 MW. The rate of forest biomass resource availability to demand was 34.2%. A thinning subsidy was provided for operational site areas larger than 5 ha in Japan. The rates from subcompartments and aggregated forests with a thinning subsidy increased to 91.4% and 190.3%, respectively. Thus, the estimated availability from aggregated forests with a thinning subsidy met the demand sufficiently in this region.

This study estimated the supply potential and availability of unused materials for woody biomass power generation in the Japanese cedar and cypress forests of Tochigi Prefecture. Then, the long-term possibility of supplying fuel woods to the existing power generation plant and the locations of the newly established power generation plants were examined. As a result, supply potentials of used and unused materials were estimated at m year and tons year respectively, whereas those availabilities were estimated at m year and tons year respectively. Although those availabilities were reduced to m year and tons year, respectively, while considering profits of forest owners, this availability of unused materials could meet the demand of the existing power generation plant which consumed tons year. Furthermore, small-scale gasification power generation plants could be installed in two cities of Tochigi Prefecture using the surplus availability of unused materials with profits for forest owners.

Estimating the Availability of Unused Materials for Woody Biomass Power Generation Using the Forest GIS. J Jpn For Soc 103: 416-423These researchers acquired the forest GIS for private and public forests from prefectures and national forests from the Forestry Agency of Japan. We then calculated incomes and expenditures such as silvicultural and harvesting as well as stumpage prices on the Japanese cedar, cypress, pine, and larch forests using the silvicultural prescription set based on the regional forest plans and operation system set based on topographic conditions such as slope angles and height differences with GIS. Finally, this study estimated the availability of unused materials for woody biomass power generation plants under operation with FIT at the end of June 2020 as the supply potential from the profitable subcompartments. As a result, supply potentials of used and unused materials were estimated at 65,490,336 m 3 /year and 13,098,067 m 3 /year, respectively whereas those availabilities were estimated at 31,080,672 m 3 /year and 6,216,134 m 3 /year respectively. Therefore, the rate of the availabilities to the supply potentials was 47.5％. Furthermore, the rate of the availabilities to the demands was 71.6％. Considering the subsidy rate of 100％ to secure the reforestations, the availabilities met the demands in Japan as a whole.