Reconstruction of short vegetation Seasons at the north of western Siberia on chronology of circannual rings

Abstract

Cores of larch (Larix sibirica Ledeb.) and spruce (Picea obovata Ledeb.) were collected on three sites in Western Siberia along the Ob river (65°15' N 65°29' E – 66°38' N 66°20' E) to reveal light rings with purpose (1) to learn possible reasons to light ring formation along the Ob river and (2) to reconstruct extreme climatic events. In the study area the light-ring formation is connected with unusual low temperature of May, June, August, but conditions of light-ring formation are different between species and sites. The period 1880–2000 has 4 years with light rings in coniferous wood at all three sites. Larch light-ring chronologies have 11 common years and spruce chronologies have 5 years. Results of a multiple linear stepwise regression showed that May and June temperatures explain 20–30% of light ring variance in spruce, and May, June and August temperatures explain 30–36% of light ring variance in larch. Infl uence of big volcanic eruption to light-ring formation in the study area was investigated.