Carbon Pools and Fluxes in Mixed Coniferous–Small-Leaved Forests and Clearcut Areas

The results of a quantitative assessment of carbon pools and fluxes and their changes in the first year after clearcutting in the middle-taiga mixed coniferous–small-leaved forest of the Komi Republic are presented. The carbon stock in the initial forest was up to 14.7 kg C/m2 with the main carbon pools in the stand (62.4%), soil (35.5%), biomass of ground cover (1.1%), and coarse woody debris (1.0%). During logging, 6.6 kg C/m2 was removed as part of the stem wood (44.8% of the ecosystem carbon stock or 71.8% of the stand phytomass carbon). In the first year after logging, the ecosystem carbon stock decreased to 8.1 kg C/m2, including 7.1% in the forest vegetation and 66.8% (5.4 kg C/m2) in the soil. The proportion of coarse woody debris increased significantly in the felled area to 1.9 kg C/m2 (23.4% the ecosystem carbon stock) due to the appearance of logging residues, which in the future should contribute to the emission of carbon dioxide into the atmosphere from the felled area. As a result of clearcutting, the input of tree litterfall onto the soil surface reduced by 42 times. An insignificant (≈10%) increase in the carbon dioxide emissions from the soil surface was detected in the felled area. Logging leads to a decrease in the removal of carbon from the forest litter into lysimetric waters. The data obtained will find application in assessing the impact of clearcutting on the carbon cycle in taiga ecosystems.