Front tracking of the translocation of water-soluble cesium deposited on tree leaves of plum

After the trunks of Cryptomeria japonica and Quercus serrata collected from the Fukushima prefecture were soaked in water, approximately 60 % of the radiocesium in the tree trunks was extracted into the water, indicating that the radiocesium in tree trunks mainly exists in a water-soluble form. The front tracking of cesium into the wood from the leaves of trees was carried out after cesium in the water-soluble form was applied to the leaf surfaces. The results demonstrated that cesium translocated from the cesium-bearing leaves, to the branch in contact with the leaves, and then into the trunk in contact with the branch.