Abstract
One of the effective means for reducing carbon dioxide emissions for the purpose of alleviating global warming is by increasing carbon fixation in the ecosystem through forest management while fixing carbon by storing it in timber used for furniture or construction materials, as well as using timber as bioenergy as a substitute for fossil fuel. The goal of this study is, by evaluating of carbon fixation in timber and the fossil fuel substitution effect, to develop a simulation model to support the overall optimization of a timber production and utilization system. The biogeochemical model (BGC-ES) based on the forest management model was employed to estimate carbon fixation of a forest ecosystem and the annual production of timber. Cases of forest management comprised combinations of timber harvest cutting periods and annual thinning area ratios. The simulations up to year 2100 were conducted with 2010 set as the base year. For each forest management case, a comparison was made from the balance of supply and demand. Timber was set to be used as building materials, woody powder and woody pellets. The amount of demand was proportionally decrease with the population. Based on the grid search, the maximum peak of cumulative carbon fixation in the ecosystem was recorded in the 90 years of rotation length and the annual thinning area ratio was 6 [%·y-1] (Case HY90t06). While the cumulative amount of timber production was at a maximum when the rotation length was 40 [y] and the annual thinning area ratio was 6 [%·y-1] (Case HY40t06). In case HY90t06, the amount of cumulative carbon fixation in the ecosystem and based on timber increased by 0.7, 3.1 [Mt-C] in 2100 respectively, in comparison with 2010. As the result, in case HY90t06, the net cumulative carbon was estimated to be 2.7 [Mt-C] in year 2100.While, in case HY40t06, the amount of cumulative carbon fixation based on timber increased by 5.8 [Mt-C], however the amount of cumulative carbon fixation in the ecosystem decreased 0.9 [Mt-C] in 2100. Regardless the most of timber was used for biomass power plant , fossil fuel substitution effect is less than other energy production, thus, the net cumulative carbon was estimated to be 1.6 [Mt-C].
