The use of tree bark as long term biomonitor of 137Cs deposition.

Airborne 137 Cs originated from the nuclear tests in the atmosphere and from the Chernobyl nuclear disaster was retained by the trees biomass and nowadays it can still be found in various concentrations in tree barks from Romania and other European countries. This study brings the first results of 137 Cs presence in tree bark from Romania on different considerations: (i) data dispersion in spruce and oak bark from NW, SW and central Romania, and the spatial variability of 137 Cs within oak and spruce bark from a natural protected forest area from Balvanyos area (Covasna County), known to be highly affected by the Chernobyl nuclear release; (ii) comparison of 137 Cs content in different tree bark species (oak, spruce, poplar and cherry); (iii) differences in 137 Cs concentrations with the bark depth layers and around the tree trunk; and (iv) comparison of mean 137 Cs values in spruce/oak bark from Romania with data from other European countries. [ABSTRACT FROM AUTHOR]