The accumulation of ¹³⁷Cs and ⁹⁰Sr radionuclides by dominants and codominants of pine forest communities in the Chernihiv region (Ukraine) was studied. The studied communities belong to the the Peucedano-Pinetum association. Our studies have confirmed the species specificity of the accumulation of 137Cs and 90Sr radionuclides by plants of biotopes of forest ecosystems. According to the indications of the specific activity of ¹³⁷Cs, the plants form the following row (as they decrease): Pleurozium schreberi – Ptilium crista castrensis – Pinus sylvestris – Betula pendula – Frangula alnus. The decrease in the specific activity of ⁹⁰Sr is observed in the following order: Frangula alnus – Betula pendula – Ptilium crista castrensis – Pleurozium schreberi – Pinus sylvestris.

The obtained data on the accumulation of ¹³⁷Cs and ⁹⁰Sr radionuclides indicate that the accumulation of ⁹⁰Sr by plants is less intense than that of ¹³⁷Cs. In the soils of natural ecosystems, the distribution of radiostrontium is similar to the distribution of radioactive cesium. Nevertheless, ⁹⁰Sr migrates down the soil profile more intensively and its main part is in the root-bearing soil layer. Therefore, the high bioavailability of ⁹⁰Sr can subsequently cause significant equal accumulations of it by representatives of the vegetation cover of the forest biocenosis.