Predicting changes in the carbon stocks of bamboo forests in Japan from 1985 to 2005

ABSTRACT Bamboo forests are expected to play an important role in mitigating climate change. However, the capacity of bamboo forests to sequester and store carbon has not been assessed on a national scale in Japan. This study estimates the changes in the carbon stock of bamboo forests (CSbamboo) in Japan from 1985 to 2005. We compiled two data sets: (1) administrative statistical data on bamboo stand area (BSA) and (2) published data on stand-level aboveground biomass for Phyllostachys pubescens Mazel ex Houz. (n = 44) and Phyllostachys bambusoides Sieb. et Zucc. (n = 13). The BSA expanded from 147 kha in 1985 to 158 kha in 2005. The average carbon density (CD) of managed and abandoned stands were 84.9 Mg C ha−1 and 115.1 Mg C ha−1 for P. pubescens and 24.1 Mg C ha−1 and 46.4 Mg C ha−1 for P. bambusoides, respectively. The CD of P. pubescens stands in Japan was higher than that in other Asian countries and regions and was comparable to the CD of other forests in Japan. The area-based method indicated that the CSbamboo increased from 10.1 ± 2.6 Tg C to 13.9 ± 1.7 Tg C during the 20-year period, representing less than 1% of the total carbon pool of the forested area. The increase in CSbamboo was primarily caused by the synergistic effect of the abandonment and range expansion of P. pubescens forests. Our results suggest that P. pubescens forests are overstocked, and the increase in the CSbamboo is undesirable.