Potential contributions of forestry and wood use to climate change mitigation in Japan

摘要

By considering trade-offs and complementarity between carbon removal from the atmosphere by forests and emission reduction by wood use, we developed a forest-sector carbon integrated model for Japan. We discuss mitigation measures for Japan based on model projections. The integrated model included the forest model and the wood use model. Based on three scenarios (baseline, moderate increase, and rapid increase) of harvesting and wood use, the integrated model projected mitigation effects including carbon removal by forests and emission reduction through the wider use of wood, until 2050. Results indicate that forests will not become a source of net carbon emissions under the three scenarios considered. The baseline scenario is most effective for mitigating climate change, for most periods. However, the sum total of carbon removal in forests and carbon emission reductions by wood use under the rapid increase scenario exceeded the one of the moderate increase scenario after 2043. This was because of strong mitigation activities: promoting replanting, using new high-yield varieties, and wood use. The results also indicated that increases in emission reduction due to greater wood use compensated for 67.9 % of the decrease of carbon removal in 2050, for the rapid increase scenario. The results show that carbon removal in forests is most important in the short term because of the relative youth of the planted forests in Japan, and that mitigation effects by material and energy substitution may become greater over the longer term.