Carbon fluxes from coarse woody debris in southern taiga forests of the Valdai Upland

Studies in three typical forest biotopes of the Valdai Upland were performed to evaluate the stocks and surface area of coarse woody debris from spruce and birch (in linear transects), its colonization by xylotrophic fungi (during reconnaissance surveys), and CO 2 emission (by a chamber method). The stock and surface area were minimum in a paludal birch forest (46.4 m 3 /ha and 960 m 2 /ha) and maximum in a decay area of spruce forest (256.1 m 3 /ha and 3761 m 2 /ha, respectively). The assemblages of wood-decay fungi had a composition typically found in southern taiga forests. The total CO 2 flux varied from 145 kg C-CO 2 /ha per year in the paludal birch forest to 462 kg C-CO 2 /ha per year in small herb–green moss spruce forest. It is concluded that air temperature is an informative predictor of seasonal C-CO 2 flux rate from coarse woody debris.