Distribution of 137Cs in the Tree Layer of Forest Ecosystems in the Zone of the Accident at the Chernobyl Nuclear Power Plant

Trends in ¹³⁷Cs distribution over the parts of coniferous (Pinus sylvestrisL.) and deciduous (Betula pendula Rocht.) trees are described. The trees have been selected in the stationary experimental plots located in southwestern Bryansk oblast, Russian Federation. The distribution of ¹³⁷Cs in the wood along the trunk height is shown to be nonuniform. The effects of ¹³⁷Cs content in the xylem sap on the accumulation of this radionuclide in the leaves and needles are assessed. The factors controlling ¹³⁷Cs accumulation in the components of woody plants are revealed, and their significance is estimated.     

Analysis of Factors Determining Accumulation of 137Cs by Woody Plants

The accumulation of ¹³⁷Cs by coniferous (Pinus sylvestris) and deciduous (Betula pendula) trees was studied in the area contaminated with radioactive products after the Chernobyl accident. The availability of ¹³⁷Cs to woody plants is determined by its vertical distribution in the soil profile, the proportion of its exchangeable form, and the distribution of tree roots in the soil. The index of biological availability of ¹³⁷C in the soil is proposed, and its linear dependence on the coefficients of ¹³⁷Cs transfer to wood is demonstrated.