Radiocaesium accumulation in stemwood: Integrated approach at the scale of forest stands for contaminated Scots pine in Belarus

Twenty years after the Chernobyl accident, root uptake from the surface layers of contaminated forest soils plays a major role in radiocaesium ((CS)-C-137) transfer to the trees and accumulation in perennial compartments, including sternwood. Trustworthy long-term predictions (modelling) of stemwood contamination with (CS)-C-137 should accordingly be based on a reliable picture of this source-sink relationship. Considering the complexity of the processes involved in (CS)-C-137 cycling in forest stands, elementary ratios like transfer factors (TF) were shown to be not very relevant for that purpose. At the tree level, alternatives like the wood immobilisation potential (WIP) have therefore been proposed in order to quantify the current net Cs-137 accumulation in sternwood. Our objective was here to compare WIP values determined for a series of contaminated forest stands in Belarus with the corresponding pools of Cs-137 available in the soil for root uptake. The comparison reveals that both indices are quite proportional, whatever the forest ecosystem features. This corroborates the relevancy of WIP as an indicator of the current Cs-137 root uptake by the trees, which could accordingly help to improve the existing models Of (CS)-C-137 cycling and the long-term management of contaminated forest ecosystems. (c) 2006 Elsevier Ltd. All rights reserved.