Radiocesium (137Cs) derived from the accident of Fukushima Dai-ichi Nuclear Power Plant remains in forests. Although a large proportion of the 137Cs in forests has been transferred to soils, the rates of transfer to soils depend on the chemical form of 137Cs, which determines the mobility of 137Cs in plant tissues and subsequently during decomposition of leaf litter. In order to understand the dynamics of 137Cs in Sugi (Japanese cedar, Cryptomeria japonica) forests, we identified the chemical forms, such as water soluble, ion-exchangeable, and residual of 137Cs, 133Cs, K, and Rb in needle-bearing Sugi branches of different ages across several years. Compared with the results for K and Rb, Cs (133Cs + 137Cs) tended to change from a water-soluble form to an immobilized form with aging of needle-bearing branch segments. In addition, it was observed that a larger proportion of the immobilized Cs were accumulated in the green outer portions of the stems through aging.

中文翻译：

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随着年龄的增长，日本雪松针中137Cs的化学形式也会发生变化。

福岛第一核电站事故造成的放射性铯（137Cs）残留在森林中。尽管森林中大部分137Cs已转移到土壤中，但转移到土壤中的速率取决于137Cs的化学形式，这决定了137Cs在植物组织中以及随后在凋落物分解过程中的迁移率。为了了解杉树（日本雪松，日本柳杉）森林中137Cs的动态，我们鉴定了含针叶杉杉中137Cs，133Cs，K和Rb的化学形式，例如水溶性，离子交换性和残留形式跨不同年龄的分支。与K和Rb的结果相比，Cs（133Cs + 137Cs）会随着针状支链段的老化而从水溶性形式变为固定形式。此外，