Assessment of Spatial Heterogeneity of Soil Properties upon Monitoring Carbon Stocks in Forest Ecosystems

A test plot of 15 ha in area has been set as a climate monitoring facility in Shchelkovo district, Moscow oblast, in 2022. Within the boundaries of the test plot, which represents one forest survey unit, a significantly diverse soil cover has been revealed, i.e., 18 soil varieties ranging from subtype to subspecies. Microrelief is considered to be the main factor of carbon stock heterogeneity: the soils of closed depressions occupied by sphagnum mosses differ significantly in carbon stocks in the litter and in the upper 10 cm of soil. For the rest of the territory, the main factors influencing the carbon stock are the percentage of physical clay in the illuvial part of the soil profile, as well as the composition and phytomass of ground vegetation. The highest variation coefficient in C stocks (40%) was registered for the 10–30 cm layer, being due, above all, to the varying thickness of the genetic horizons composing it. Geospatial analysis allows us to pass to the spatial assessment of variation in soil properties and further modeling and forecasting the carbon stock dynamics taking into account the spatial heterogeneity of the territory. Identifying the factors that control carbon stocks in soils will help to work out modeling scenarios aimed at developing measures on increasing carbon accumulation in forest ecosystems through changes in the vegetation structure.