Carbon Stocks in Harvested Wood Products in Various Countries of the World

With the aim of supporting measures for climate change mitigation, we estimated carbon stocks in harvested wood products （HWP） in various countries of the world between 1961 and 2016. Global carbon stocks in HWP in 2016 under the stock change approach （SCA） as the carbon accounting approach and first order decay （FOD） as the decay function were estimated to be approximately 73.3 hundred million tons of carbon （t-C）, which represents an increase of 2.5 times over the past 55 years. It was confirmed that the annual increase of global carbon stocks between 2015 and 2016 was approximately 1.1 hundred million t-C/year, which was the maximum value during the entire target period. At the national scale, in 2016, the largest carbon stocks of HWP, listed in descending order, were in the United States of America, China, the Russian Federation, and Japan. With respect to the annual increase of carbon stocks for the period from 2015 to 2016, China contributed the most to the global annual increase, nearly 67% of the total. On the other hand, global carbon stocks in 2016 under the production approach for the second commitment period of the Kyoto Protocol （PAkp） were estimated to be approximately 68% of those under the SCA, revealing that the PAkp could conservatively estimate the global carbon stocks in HWP. Furthermore, annual changes of carbon stocks obtained using the normal distribution varied significantly from those obtained using the FOD, suggesting that decay functions for an appropriate method for estimating carbon stocks of HWP need to be reconsidered.