Wood samples of larch (Larix sibirica LEDEB.), spruce (Picea obovata LEDEB.) and pine (Pinus sibirica DU TOUR), growing in the northern taiga of western Siberia, were screened for the occurrence of light-rings - an anomaly of tree-ring formation in extreme environments. Light-rings were dated and the resulting species-related light-ring chronologies were used (1) to explore possible causes of light-ring formation and (2) to reconstruct past extreme climatic events. Light-rings in spruce and larch were mainly formed by an unusually cool May, June, August and September, whereas light rings in pine were associated with a cool July. Between 1740 and 1997 we identified seven years when all three species had formed light-rings and 15 years when light-rings were formed in larch and spruce, but not in pine. As concluded from linear regression, summer temperatures explained 43 and 50% of the variability of light-ring intensity in spruce and larch, respectively. However, not all light rings were formed in below-average cold summers but in a few cases even in above-average warm summers, indicating the limitation of this approach.