Carbon Pools in Forest and Meadow Postagrogenic Ecosystems on Albic Endocalcaric Retisols of Southern Taiga

Vegetation successions on abandoned arable lands are an important factor of changes in the ecosystem carbon stocks. Note that tendencies of changes in separate carbon pools may be differently directed. The article presents a comparative assessment of carbon stocks in the belowground and aboveground phytomass, deadwood, litter, and mineral horizons of soils in a grassy birch forest, a tall-herb alder–willow birch forest, and an herbaceous meadow developed on abandoned arable lands in Cherepovets district, Vologda oblast. The total carbon stocks in the studied biogeocenoses ranged from 115 to 188 t/ha and increased in the following order: herbaceous meadow < grassy birch forest < tall-herb alder–willow–birch forest. The proportion of soil carbon, litter included, in the total carbon stock reached 58% in the forest biogeocenoses and increased to 95% in the meadow biogeocenosis; the contribution of litter to the total carbon stock did not exceed 3%. In the forest biogeocenoses, the carbon stock in the phytomass ranged from 51 to 88 t/ha, or 36–47% of the total carbon stock. The deadwood carbon stock in the forest biogeocenoses was about 1% of the total ecosystem carbon stock; large woody remains (such as fallen trees and stumps) represented a larger part (70%) of the deadwood carbon stock. The transition from meadow to forest biogeocenoses was accompanied by a redistribution of carbon stocks between the main pools and an increase in the total ecosystem carbon stock. The results obtained can be used to validate and develop a baseline for forest climate projects in the southern taiga subzone.