Forest Growing Conditions Affect the CO₂ Emission from the Soil Surface in the Middle Taiga Pine Forests of the Komi Republic

Obtaining the experimental data on soil respiration is relevant due to significant range of CO₂ emission estimates in different ecosystems. The aim of work was to characterize CO₂ emission from soil surface of pine forests growing in different conditions on North-East of European part of Russia. The studies have been carried out in immature and mature pine forests Sphagnosa, Myrtillus and Lichen types located in the Institute of biology of the Komi Science Center, RAS forest stations. Carbon dioxide emission was measured using LI COR 8100 during the May-October periods in 2008–2017. A brief weather conditions characteristic was given. Higher values of the CO₂ flux from the soil surface was observed in July (1.9–2.9 g С m^–2 day^–1 in Sphagnosa type) and August (2.5–6.6 g С m^–2 day^–1 in Myrtillus and Lichen types). The year-to-year variability and influence of weather conditions on soil respiration were shown. The soil temperature had a close and positive relationship (R² = 0.49–0.77) with CO₂ emission whereas correlation with soil moisture was weak. During summertime the efflux of C-CO₂ in a pine forest of Myrtillus type was 188–442 g C m^–2, during the vegetation period (01.05–30.09) – 279–563 g C m^–2 and the snowless period (01.05–31.10) – 308–583 g C m^–2, which is 1.5–1.8 times higher than in the pine forests of Sphagnosa and Lichen types during the snowless period (р = 0.014) and growing season (р = 0.020). In summertime the losses of carbon were similar (р = 0.106). The pine forests of Sphagnosa and Lichen types were comparable in С-СО₂ efflux both during the vegetation and the snowless periods (p > 0.05). These data are important in assessing the expenditure part of the carbon balance in forest ecosystems in the European North-East of Russia.