Biomass carbon sinks in Japanese forests: 1966–2012

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 up to 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, to coincide with the final year of the Kyoto Protocol's first commitment period. Forest area and growing stock data were analysed. Then, two models for predicting the change in forest area and growing stock were developed. Results showed that most natural forest loss resulted from conversion to plantation forest. The total above-ground and below-ground carbon stock in Japanese forests has been estimated to have increased from 1114.8 TgC in 1966 to 2076.0 TgC in 2012, representing an increase of 20.9 TgC year -1 over the same period. During the first commitment period of the Kyoto Protocol (2008-2012), annual carbon sinks were estimated at 20.1 TgC, of which ∼76.9 per cent were sequestered in plantation forests. Of the 20.1 TgC year -1 , eligible carbon sinks are estimated at 10.2 TgC or ∼78.7 per cent of the maximum or capped amount as allowed under the Marrakesh Accord. Although further effort is needed so that the capped amount of 13 TgC year -1 could be achieved, this study suggests that carbon sinks through forest management could be used to offset industrial carbon emissions.