THE ANALYSIS OF GROWTH-PARAMETERS OF RUSSIAN BOREAL FORESTS IN WARMING, AND ITS USE IN CARBON BUDGET MODEL

A model and experimental study of the influence of warming on tree gro wth in Russian forests was carried out. Data on parameters of large-sc ale carbon cycle models, characterizing the temperature response, are discussed. Pine (Pinus sibirica) and fir (Abies) radial growth in cold and warm years was measured in the Baikal region. It was obtained tha t typical values of growth rate increase in warming in middle and nort h Siberian taiga are equal to 12-15% degrees C-1, that is 3-4 times mo re than in south taiga. There is a coincidence of these values with ou r estimations of changes in photosynthetically active radiation during the vegetation period, which can increase by 15, 12.5 and 6.5% in nor th, middle and south taiga under 1 degrees C warming. A dynamic model was used for estimation of climate-induced changes in carbon balances of different forest zones in Russia. The calculations were carried out by using three variants of growth parameters (medium variant was base d on results of measurements). Changes in the parameters induce very s ignificant changes in additional CO, uptake caused by climate factors. According to our medium model estimation, this uptake is currently eq ual to 120 . 10(12) g C yr(-1) and it has the tendency to increase in the future.