Abstract
With regard to 7Be, a natural radioactive nuclide, the botanical capturing characteristics were compared between eight species of those trees which grow in a local district. The mechanism of such botanical capture by their leaves was discussed. The amounts of captured 7Be were different by tree species. Higher radioactivities were found in the coniferous trees than in the broadleaf trees. The seasonal change of 7Be radioactivity in leaves was significantly higher in winter and spring and lower in summer. Since airborne or fallout 7Be particles stay on the upper face of leaves, the depositted amount depended on the surface area per weight of leaves particularly for evergreen trees. Because the 7Be amount in leaves depended on the fallout capturing ability of leaf's superficial skin as well as the cleaning effect of rain and the like, the radioactivity on the surface can change depending on the surface condition of leaves even in the case the levels of 7Be fallout stayed the same.
