Biotic Predictors of Carbon Stock Variation in Light-Textured Forest Soils

The contribution of biotic factors to the variation of soil carbon stock in forests of the Republic of Karelia, Leningrad oblast (Karelian Peninsula), and Bryansk oblast (Bryansk Forest Nature Reserve), formed on soil-forming rocks of light granulometric composition, is assessed. Groups of biotic predictors characterizing the vegetation and macrofauna are analyzed, and their contribution to the variation of the soil carbon stock in soil layers and horizons is estimated using the hierarchical decomposition method. It is shown that in coniferous-broad-leaved forests the relative contribution of biotic predictors to the variation of litter carbon stocks is higher, while in boreal forests, it is in the mineral layers of 0–50 cm. The most informative predictor for the OFH subhorizon of the litter and mineral horizons was the indicator of litter quality of the C : N ratio.