This study determined the rate of decomposition of fine roots and leaf litter from birch, larch, and pine, and compared the impact of fine root decomposition and leaf litter on carbon, nitrogen, and phosphorus accumulation in various regenerated and reconstructed forest ecosystems. The control plots were located on podzol soils in managed forest non-degraded habitats. Over a one-year experimental season, the decomposition of birch and larch fine roots released less carbon in comparison to leaf litter. The carbon mass-loss rates were 16% for birch roots and 15% for larch roots, while for birch and larch litter, the rates were 36% and 27%, respectively. For nitrogen, mass-loss rates were 48% for birch fine roots and 60% for larch and pine fine roots, whereas for pine and birch litter the rates were 14%, and 33% for larch litter. The results of our study prove the important role of fine root input to the soil's carbon, nitrogen, and phosphorus pool and additionally their significance for CO2 sequestration within the studied regenerated terrestrial ecosystems. [ABSTRACT FROM AUTHOR]