Toward the Estimation of Radiocesium Activity Concentration in Trunks of Coppiced Quercus serrata: Leaf Availability Instead of Felling

Abstract

AbstractWith the long-term goal of resuming the use of contaminated deciduous broad-leaved forests, which previously provided bed logs for the cultivation of shiitake mushroom (Lentinula edodes), we are developing a method for estimating the radiocesium (137Cs) activity concentration in the trunks of coppiced konara oaks (Quercus serrata) by using current-year branch in the dormant stage. In this study, we examined whether leaves could be used instead of current-year branches in the dormant stage. Our assessment revealed that the leaves obtained at the phenologically stable stage (from the end of the flushing stage to prior to the defoliation stage) can be used to estimate the 137Cs activity concentration of current-year branches (in the dormant stage) by multiplying the leaf 137Cs activity concentration by 0.54 ± 0.03. This result suggests that leaves collected at this stage are suitable for the estimation of 137Cs activity concentration in the trunk. Given that the leaves are more easily to sample than the current-year branches, we propose that 137Cs activity concentration in the trunk of coppiced konara oak can be estimated more easily with this method using leaves.