[M-IS14] Biogeochemistry

[MIS14-06] Development and application of forest ¹³⁷Cs cycling model "FoRothCs"

*Kazuya Nishina¹, Shoji Hashimoto², Shinji Kaneko², Masabumi Komatsu², Shinta Ohashi², Naohiro Imamura², Seiji Hayashi¹ (1.NIES, 2.FFPRI)

Keywords:137Cs cycling, plantation forest

Following the Fukushima Dai-ichi nuclear power plant (FNDPP) accident in March 2011, 14.5 PBq of ¹³⁷Cs were released into the atmosphere and deposited onto surrounding terrestrial ecosystems and largely on forest ecosystems. The big difference in the contaminated forest between FNDPP and Chernobyl is that the most contaminated forest is in Fukushima consisted of plantation forests for timber production. Because of the physical decay constant of ¹³⁷Cs (30.1 year^-1), the fate of ¹³⁷Cs is important for long-term management of these forests. So, we have developed forest Roth-C and Cs cycling model "FoRothCs" to predict the redistribution of ¹³⁷Cs in forest ecosystem especially for plantation forest in decadal timescale. This model can simulate ¹³⁷Cs inventory and concentrations and activities of 7 compartments of a forest ecosystem (see Figure: diagonal components are the compartments and other components are transfer processes of FoRothCs) with biomass production (including stem volume of a tree). In this study, we will introduce "FoRothCs" and the application to 6-years monitoring data in 4 forest sites in Fukushima with different amount of ¹³⁷Cs deposition. To reconcile FoRothCs outputs to these observations and estimate parameters regarding ¹³⁷Cs transfer processes, we used an approximate Bayesian computation.