Estimating Annual Available Amounts of Forest Biomass Resources with Total Revenues and Costs during the 60-Year Rotation in a Mountainous Region in Japan

This study extracted production forests and estimated the annual available amounts of forest biomass resources under profitable forest management. Production forests were extracted as sub-compartments where expected revenues surpassed all costs, from planting to final harvesting, for a 60-year rotation. These revenues and costs were estimated for two types of timber harvesting systems (a conventional operation system using a chainsaw and mini-forwarder, and a mechanized operation system using a processor and forwarder) and three types of forest biomass harvesting systems (normal extraction, landing sales, and no biomass extraction) in each sub-compartment using a geographic information system. Then, annual available amounts of forest biomass resources were estimated on the basis of annual supply potentials from production forests. The model was then applied to Nasushiobara City and the Kanuma area in Tochigi Prefecture, Japan. As a result, the number of profitable sub-compartments was estimated as 2,814 out of a total of 5,756 in Nasushiobara City, and 22,872 out of a total of 32,851 in the Kanuma area. The annual amounts of available forest biomass resources were estimated as 11,849 m y and 115,213 m y in Nasushiobara City and the Kanuma area, respectively. These amounts largely exceed the annual demands of a 500 kW woody biomass power generation plant planned in Nasushiobara City (6,000 m y) and a chip production factory located in the Kanuma area (12,000 m y), respectively. €1 = 143 yen on March 13, 2011