Factors of spatiotemporal variability of CO2 fluxes from soils of southern taiga spruce forests of Valdai

Factors determining the spatiotemporal variability of carbon dioxide emission from soil on various scales (from hours and days to seasons of the year and multiple years, and from microbiotopes to mesobiotopes) were identified using the results of a five-year study in the southern taiga spruce forest at Valdai highlands (Novgorod oblast). The air temperature close to the soil and that of the top layer of the soil, the humidity of the top layer of the soil, the precipitation during the preceding period, the litter thickness, the minimal distance to the trunks of dead standing and fallen spruce trees, and the coefficient of enhancement of microbial respiration were among the most significant factors. The soil temperature at a depth of 1 cm was the only variable of significance for both spatial and temporal distribution. The necessity of taking both spatial and temporal factors into account upon the prediction of the estimated value of CO2 emission by the soil has been demonstrated.