C01_P02

Climatic signal in tree ring δ¹³C and its temporal stability - case study for Suwałaki region

Pawełczyk S¹, Benisiewicz B²

¹Silesian University Of Technology, Gliwice, Poland, ²Silesian University Of Technology, Gliwice, Poland

Isotopic measurements in tree rings can be very useful in reconstructing past climate. However, such reconstructions may encounter some problems. One of these, especially at the present time, is an environmental change caused by anthropopression, which also affects the stable isotope ratios.

Investigations of stable carbon isotope composition in α-cellulose extracted from tree rings of pines (Pinus sylvestris L.) growing in the ecologically clean Suwałki region, North Eastern part of Poland, are undertaken. Carbon isotopic composition of α-cellulose samples was determined using a mass spectrometer coupled to the elemental analyzer. Analyzed isotope record cover the period from 1932 to 2003. Values of δ¹³C measured in the α-cellulose of tree rings were compared to meteorological data. Values of δ¹³C in cellulose strongly respond to temperature, insolation, relative humidity, and precipitation of the current year. The relative August humidity values yield the best correlation between climate and carbon isotope data (r=-0.65). Relations between isotopic and meteorological data demonstrate that precipitation influences the stable carbon isotopic ratios to a lower extend than the humidity. Using a moving interval technique, the temporal stability of correlation between isotope chronology and climate was investigated. These studies showed no climate signal stability for the years of the maximum industrial human activities.

This work is a part of EU ISONET project No. EVK2-CT-2002-0014 (400 years of Annual Reconstructions of European Climate Variability using a High Resolution Isotopic Network).