Predictions of Carbon Stock in Forests of the Southern Moscow Region under Different Scenarios of Forest Use

The results of forest simulation modeling of the dynamics of carbon pools and fluxes in forest ecosystems under different forest management scenarios are considered using the example of the Dankovsky forestry district (south of the Moscow oblast, subzone of coniferous-broadleaved mixed forests). The impact of changes in forest management practices such as the reserve regime, the reduction in the proportion of forest lands as a result of residential development, and zoning of the territory with an emphasis on increasing the recreational use of forests on the carbon balance is analyzed. In computational experiments, a set of Russian models is used: the FORRUS-S dynamic model of a forest stand, the Romul_Hum model of soil organic matter dynamics, and the SCLISS model of the hydrothermal regime of soils. Calculations are performed for a time period of 100 years at the forestry unit level, and they are also aggregated at the level of the entire forestry district. The diversity of types of forest growth conditions (FGCs), together with the species diversity and the initial different ages of stands, determine significant variations in the calculated indicators of forest stand production and the quantity and quality of plant litter entering the soil. For all cases, model estimates of changes in carbon reserves occurred in the forest stands within the initial 40–60 years with a subsequent decrease in the calculated values. Under the conservation scenario, an increase in the organic substance reserves in forest litter and soil is observed: for FGCs C2 and C3, an increase of over 100 years was approximately 5–10 kg m^–2; for the remaining FGCs, it is at the level of 2–3 kg m^–2 in terms of carbon. Under the economic use scenarios, a comparative “levelling” of forestry district area towards the lower end of the spectrum is shown in terms of soil carbon reserves. The maximum ecosystem carbon stock is calculated for FGC C2 and C3, and the minimum is for A5 and C4. Depending on the scenario, over 100 years, the total net absorption of carbon by the forests of the Dankovsky forestry district (with a total area of forested land of 6836 ha) is estimated within the range of 0.15–0.57 Tg.