Changes in Radioactive Cesium Distribution in Forests

Radioactive cesium deposited on trees, leaves and branches, etc. in the surveyed forests gradually transferred into soil from 2011 to 2012 and the percentage of radioactive cesium found in soil increased significantly.

In the surveyed quercus serrata forest and cedar forest in Otama in Fukushima Prefecture, most of the radioactive cesium had transferred into soil in 2016, with the percentage of radioactive cesium in soil accounting for approx. 80% to 90% of the total. Radioactive cesium in organic layer slightly increased in the cedar forest in Otama in 2016 compared with the previous year.

In the surveyed cedar forest in Kamikawauchi in Fukushima Prefecture, there is a larger amount of leaves and branches of trees and a thicker organic layer, as observed in the graph.

• Included in this reference material on January 18, 2016
• Updated on February 28, 2018