In this thesis, the abundance of the timber offcuts of felling per one year was calculated as a test, and the amount of CO2 emission reduction when those were burnt in substitution for fossil fuel was calculated in the forest of Nagano prefecture. A CO2 emission reduction effect when the moisture in the timber offcuts was reduced was calculated as a test. Following results were obtained by researches.
1. The amount of the timber offcuts felling per one year were quite 1,006,000 m3/year in the forest of Nagano prefecture.
2. When one log is burnt, The amount of CO2 emission reduction when it is burnt after a log was left in outdoor depository has more quite 17 kg-CO2/log than when it is burnt as soon as it was felled
