Cycling of radiocesium in two forest ecosystems in the state of Rhineland-Palatinate

In order to estimate the long-tern bioavailability of radiocesium, studies on Cs-137 + 134 cycling are being conducted on a spruce and an oak stand in Rhineland-Palatinate, FRG. Trees seem to filter Cs-bearing aerosols and retain them temporarily in the canopy. Despite the very low contents in clay and silt and the low cation exchange capacity of the forest soils, radiocesium is moved vertically only at an extremely slow rate. On the other hand, it is obvious that radiocesium is highly mobile in trees and can easily be transported from older parts of the vegetation into new shoots. In forest ground vegetation, striking difference in the Cs-contamination and behavior of different species could be observed. (author)