137Cs Distribution in Trunk Wood of Scots Pine Depending on Age Class

The article examines peculiar features of distribution of 137Cs, which is a major radionuclide, resulting from the Chernobyl release, in trunk wood of Scots pine, depending on the age class. It is shown that, in the long term after the fallout, the distribution of 137Cs across a tree stand of pine biogeocenosis in Bryansk Polesie (Russian Federation) affected the most by the Chernobyl accident at contamination densities of 2183 kBq m–2, exceeding the level established by the Law of the Russian Federation “On Social Protection of Citizens Exposed to Radiation As a Result of the Chernobyl Disaster” and categorizing the area as radioactively contaminated (37 kBq m‒2), as well as the minimum (0.23 kBq kg‒1) and mean (2.42 kBq kg–1) of the specific activity of 137Cs in wood, does not exceed the norms for timber-based products in various applications, except timber used in residential construction. The obtained original data clearly point toward a downward trend in the radionuclide specific activity depending on the stand age in 137Cs distribution both by the trunk height (from the top of the tree to the butt) and by mean wood contamination values in general. Therefore, this component should be sampled taking into account the age groups in 10-year increments for the most adequate assessment of the possibility of wood contamination and compliance of the levels of the radionuclide specific activity with the normative values specifically in the context of the use in construction.