Ecosystem Exchange of Carbon Dioxide and Water in Cowberry-Lichen Pine Forest in the Middle Taiga Subzone of Eastern Europe

To assess carbon dioxide exchange in the ecosystem of cowberry-lichen pine forest, 8790 eddy covariance measurements were made during the summer-autumn period. The annual cycle of CO2 fluxes between forest and atmosphere was reconstructed using regression equations. The total net CO2 exchange, gross photosynthesis, and ecosystem respiration in the pine forest were estimated at -103, -407, and 304 g C m(-2) year(-1), respectively. Total evapotranspiration in June to September was 98 mm, and the efficiency of water utilization for gross photosynthesis varied about 2-3 g C kg(-1) H2O. A close correlation was revealed between the daily average values of gross photosynthesis and total evaporation over the forest canopy. The rates of net ecosystem CO2 exchange and evapotranspiration in the cowberry-lichen pine forest proved to be significantly lower than in a spruce forest of the East European taiga zone, which confirms the hypothesis that the structure of forest cover has an effect on the parameters of energy and mass exchange at the surface layer of the atmosphere.