Species Composition of Phytocenoses, Structure, Viability, and Carbon Content of the Modal 120–140-Year-Old Pine Forest Stands in the East European Forest-Steppe

The aim of the study was the silvicultural assessment of the species composition, structure, sanitary condition, productivity, and carbon content of three modal 120-140-year-old Scots pine forests in the East European forest-steppe of the Russian Plain. Silvicultural, forest inventory and mensuration methods were used to analyze the characteristics of these stands. The distribution models of trees by diameter and growth were analyzed, and the reserves of aboveground and underground phytomass for each forest stand were assessed. All surveyed forest stands are highly productive and in excellent sanitary condition. The forest stand on moist moderately fertile soils was characterized by higher forest mensuration characteristics on average. Allometric relationships between the diameter of forest stands and their height have been established, which will allow mathematical modeling and forecasting of the dynamics of forest stand characteristics in forestry practice. The surveyed forest stands on moderately moist moderately fertile soils store 112.9-122.6 tons of carbon per hectare (tC/ha) in their phytomass, on moist moderately fertile soils - 182.8 tC/ha. About 73% of carbon reserves are concentrated in the above-ground phytomass, and about 27% in the underground phytomass, respectively. Trunk wood accumulates the main part (58-60%) of the aboveground phytomass of the studied pine stands.