[en] Considered in the paper are influences of interspecies relationships between woody plants comprising main storeys of forest phytocenosis on Cs 137 accumulation in principal timber species in Belarus growing in radiation-contaminated mixed two-species forest stands by comparison with single-store y stands consisted of the same species. The effect of interspecific distinctions was revealed in woody plants as Cs 137 deposition in forest phytocenosis decreased. This effect was governed by the joint action of root systems of trees, the distribution of the available Cs 137 along the vertical soil profile and the effect of root exometabolites of the trees. (authors)