Relevance. Wildfires dramatically change the conditions for the existence of ecosystems. Ecosystem restoration stretches for many years and depends on many factors. In the mire, the chemical composition of peat and plants in post-pyrogenic sites serves as an indicator of the transformation of biogeochemical cycles. Aim. To compare the intensity of element absorption by plants-dominants of each tier in pristine and post-pyrogenic mires of different regions 6–8 years after the fire. Methods. Comparative-geographical, expeditionary, landscape descriptions of key sites, conjugate analysis, biogeochemical, statistical and some other methods. Results and conclusions. The paper presents the results of studies of post-pyrogenic sites of mires located in the taiga and forest-tundra zone of Western Siberia. In three mires, two of which are located in the taiga zone and one in the forest-tundra, samples of dominant plants of each tier and peat in the root zone were collected in the pristine and post-pyrogenic sites. In the collected samples, we determined the concentration of Na, Mg, P, K, Ca, Mn, Fe, Cu, Zn, Cd and Pb. We found that a characteristic feature of the post-pyrogenic sites of the mires is an increased content of Zn and Cd in plants and peat, compared to the pristine mires. When comparing the intensity of absorption of elements, we found that in the post-pyrogenic sites, the biological absorption coefficient of Cd increases and the biological absorption coefficient of Mn decreases. We found that post-pyrogenic transformation is expressed in a quantitative change in the chemical composition of peat and plants, and for each species we found features of element absorption in different geochemical conditions.