To elucidate interannual changes in the vertical distribution of 137 Cs in forest ecosystems
contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident, we investigated 137
Cs inventories in forest soils (both organic and mineral soil horizons) at 10 sampling plots
with different 137 Cs deposition levels and dominant species for up to 10 years after the
accident. We examined the temporal variation of the 137 Cs inventories by depth with
exponential regression models (assuming that the transition and partitioning of 137 Cs are …