抄録
Objective. Woody biomass has attracted considerable attention as a power generation system that utilizes wood resources. The woody biomass power generation system is expected to reduce carbon emissions and, by necessitating forest management for the purpose of wood chip supply, to increase primary production of forests. This paper describes the development of evaluation models for forest management and shows the environmental impact of introducing the woody biomass power generation system in terms of Japanese red pine forest management. In this study, influence of primary production, CO2 emissions and land use are calculated based on the “Life cycle Impact assessment Method based on Endpoint modeling 2 (LIME2)” methodology. The targeted forest comprises Japanese red pines, 30, 40, 50 and 65 years old. Management plans catering to each forest age bracket are set according to the logging area in accordance with the forest management guidelines. The management period of these plans is 20 years with two management methods, forest-thinning and final cutting.
Results and Discussion. The evaluation results made it clear that forest management had a much greater effect in terms of CO2 emission and land use. Comparison of the environmental improvement rate per unit area in each plan shows that forest-thinning and final cutting have a similar effect when a forest is 30 and 40 years old, but that just final cutting is more effective for a forest aged 50 and 65 years.
Conclusions. This study indicates that the forest management effect is greater than the CO2 emissions reduction effect. The process of supplying wood chips for the power generation system is judiciously planned considering forest age and characteristics, and is an important part of reducing environmental impacts.
