Transformation of the carbon budget in middle-taiga spruce forests on swamp-podzolic soils during winter clear fellings

The paper presents the characteristics of the main components of the carbon cycle in the ecosystems of mature spruce forests: blueberry moist, polytrichum-sphagnum, and in fellings of these spruce forests on peaty podzolic gley soils. Income and expenditure items of the carbon budget of phytocenoses are assessed according to the indicators of production and destruction processes of organic matter. It has been established that the total carbon pool in the ecosystems of mature spruce forests is 160–194 t∙ha−1, of which in plants of phytocenoses 44.4–57.8%, in large wood residues (deadwood) 2.1–9.7%, in the soil including litter and mineral layer 35.8–45.9%. In the ecosystems of fellings carbon reserves of organic matter are equal to 106–113 t∙ha−1, of which in soil 62.5–72.5%, in phytocenoses plants 18.0–25.2%, in large wood residues 9.5–12.3%. The annual carbon sequestration by phytocenoses of mature spruce forests is 2.4–3.5 t∙ha−1, in felled areas – 1.8–2.2 t∙ha−1. In the accumulation of carbon in spruce forests the leading role belongs to the tree stand, and in the fellings – to ground cover plants. The amount of carbon entering with the litter is 2.0–2.1 t∙ha−1 in spruce forests, and 1.4–1.6 t∙ha−1 in fellings. The carbon released during the decomposition of the litterfall plant residues in the fellings is 0.54–0.63 t∙ha−1, which is 37.2–37.6% of the annual decomposition of the litterfall plant residues. It is shown that mature spruce forests are a place of sink and fellings is a source of carbon.