[en] After the Fukushima Daiichi Nuclear Power Plant accident, it was found that deciduous trees took up fallout radiocesium (¹³⁴Cs + ¹³⁷Cs) through their barks and stored them in the tree bodies in 2011. After that, radiocesium concentrations in trees have been decreasing, and in 2013, most fruits harvested in Fukushima prefecture became lower than detection limits. Although fresh fruits were low in radiocesium concentrations, dried fruits can have higher radiocesium concentration during drying process of fresh fruit without any loss. Thus dried fruits would exceed the standard limit of 100 Bq kg^-1 in some case. Dried persimmon is one of the special food products in Fukushima prefecture; it is therefore important to know the effective half-life (T_eff) of radiocesium in persimmon trees. In this study, we measured radiocesium concentrations in persimmon leaves and fruits from the end of April 2011 until November 2013 to calculate T_eff. The observed T_eff values for ¹³⁷Cs were 210 d for leaves and 270 d for fruits showing small differences among them. Thus the use of ¹³⁷Cs concentration data for fruits in Fukushima Prefecture to estimate T_eff in persimmon trees would be applicable. Food monitoring data compiled by Ministry of Health, Labour and Welfare, Japan were used for this purpose. Using detected persimmon fruits data collected in six local communities in 2011-2013, T_eff value was calculated in each community; the average value was 405±63 d (301 - 469 d), which was about 130 d slower than that was observed in Chiba. However, it was clear that the effective half-life of radiocesium in persimmon trees was about 1 year for the last three years. Since the T_eff is expected to become longer in the long-term period compared to the early stage after the accident, it is necessary to carry out continuous ¹³⁷Cs measurements to predict ¹³⁷Cs in persimmon more precisely. (author)