Carbon Dioxide Emission from the Soil Surface in a 10-Year-Old Felled Area of Pine Forest in the European Northeast of Russia

Experimental data on soil respiration are needed for estimating the effect of industrial cutting on the carbon cycle in forest ecosystems. Investigations were carried out during snowless periods of 2019-2021 on a felled area of pine forest ten years after clear cutting (Komi Republic, Russia). The studied soil is a Gleyic Folic Albic Podzol (Arenic). The CO2 emission was measured by the closed chamber method using LI COR 8100 analyzer. Weather conditions and soil temperature dynamics at 10-cm depth were characterized. Weather conditions are shown to strongly influence the soil respiration rate. More intensive CO2 flux from the soil surface was observed in warm summer with insufficient precipitation. Mean monthly emissions from skid trails were 1.3-1.9 times higher than emissions from felled forest strips characterized by relatively small soil cover disturbance. A significant positive correlation (R-2 = 0.12-0.86) was revealed between soil temperature at a depth of 10 cm and respiration from the soil surface. A significant correlation between CO2 flux and moisture content in the topsoil was observed on skid trails in a year with abundant precipitation, while in dry year such a correlation was absent. For forest strips, a reverse relationship between the CO2 flux and the soil moisture in wet and dry years was observed. Soils of forest strips emitted 303-379 g. m(-2) owing to soil respiration during the snowless period; soils of skid trails, 419-573 g. m(-2), which corresponds to 60-75 tons of CO2 for the entire felled area (5 ha). A larger part (86-90%) of carbon efflux during snowless period (May-October) occurs during the growing season (May-September), and the contribution of summer period (June-August) is 56-65%. The data obtained form the basis for estimating the role of timber harvesting in the carbon cycle of taiga forests.