Possible Effect of the North Atlantic Oscillation on Vital Activity of Trees (Southeast of Western Siberia)

The response of forest ecosystems to changing climate conditions is studied by many researchers. In this work, the relationships between variations in the residual gas content in discs of coniferous and deciduous trees growing in and around Tomsk (southeast of Western Siberia) and the North Atlantic Oscillation (NAO) are analyzed. We have found (1) a significant correlation between the air temperature in Tomsk region and the NAO index; (2) coherent fluctuations in the chronologies of gas components of deciduous tree discs and in the air temperature during the growing season around a 4-year cycle; (3) the correlation coefficients of the NAO index with the chronologies of CO₂ (CO₂ + H₂O) and the ring width of the six (of eight) tree discs. A conclusion is drawn that the North Atlantic Oscillation can affect the life activity of some Siberian tree species (on a 4-year time scale). The results can be used in studies of biospheric and atmospheric processes with the aim of considering the effects of remote sources of air pressure variations on forest ecosystems.