Potential carbon sequestration in Japanese forests during the first commitment period of the Kyoto protocol

The role of forests in absorbing atmospheric carbon has been recognized under the Kyoto Protocol, which allows signatory countries to use forests as a mitigation option. Although several studies have estimated carbon stock changes in Japanese forests, most only estimate changes through 1995 or ignore carbon stock changes in natural forests. This study is the first attempt to estimate carbon stock changes in Japanese forests from 1966 to 2012, the final year of the Kyoto Protocol's first commitment period. Forest land use and growing stock data were analyzed. Then, two models of forest land use change and growing stock were developed. Analytical results showed that most natural forest loss resulted from conversion to plantation forestland, while a minor portion was converted to other forms of land use. Carbon stock in Japanese forests increased from 857.3 TgC in 1966 to 1594.2 TgC in 2012, representing an increase of 16.0 TgC year-1 over the same period. During the first commitment period of the Kyoto Protocol, annual carbon sequestration was estimated at 15.3 TgC, of which about 77.1% was sequestered in plantation forests. Only carbon sequestration in specially managed forests is credited under the Marrakesh Accord; thus, eligible carbon is expected to be lower. When data of specially managed forests become available, further study of eligible carbon sequestration is necessary because it could provide a baseline for decision making about the use of carbon sinks for carbon emission mitigation.