<i>Pinus sibirica </i>Du Tour RESPONSE TO CLIMATE CHANGE IN THE FORESTS OF THE KUZNETSK ALATAU MOUNTAINS
Climate change has a direct impact on the forest ecosystems of the boreal zone. Temperature increase has a stimulating effect on the advancement of a tree line along the elevation gradient, increase of tree radial increment and stand density. The object of the study was the stands formed by the Siberian pine growing in the forest-tundra ecotone of Kuznetsk Alatau Mountains. The rate of timberline and tree line advancement were estimated using GIS-technology and field research. It has been established, that the beginning of the Siberian pine advancement along the elevation gradient coincides with the period of air temperature increase. Estimated speed of tree line advancement is approximately 0.2-0.3 m/year; timberline ~ 0.5 m/year. The average radial increment after 1980 was 25 % higher than the radial increment over the same period of the previous years. At the same time after a marked increase of the radial increment in the early 1980s, a negative trend is observed up to the local minimum of 1999 ( r <sup>2</sup> = 0.52). Dendroclimatic analysis indicates a negative influence of July-September temperatures ( r = -0.63) and that of winter precipitation ( r = -0.81) on radial increment, while the amount of July-September precipitation ( r = 0.54) and root zone wetness content during the vegetation period ( r = 0.73) show positive correlation with radial increment. During the previous period from 1967 to1982, a negative effect of winter precipitation on radial increment was also noted ( r = -0.69), whereas May-June temperatures demonstrated a positive effect on radial increment ( r = 0.66).