Common Yew (Taxus baccata) as a climate archive: Reconstructing 200 years of temperature change in Georgia (Caucasus)

Abstract

Encompassing 44 % forest cover across a diverse elevational gradient (sea level to 2500 m asl) and encompassing biomes ranging from semi-arid to temperate rainforests, Georgia, a country within the Caucasus biodiversity hotspot, presents an unexploited opportunity for dendroclimatological research. This study assesses the suitability of Common Yew (Taxus baccata) for dendroclimatic reconstruction in Georgia. We develop the first dendrochronology in Georgia’s Batsara Nature Reserve by obtaining the species' single master chronology, analyzing the relationship between annual tree-ring growth and climate, and reconstructing past climate over the last 445 years. Results indicate that the average wintertime temperature is the most important climatic driver for the formation of the annual rings, with narrower rings corresponding to colder winters and delayed spring onsets. The reconstructed temperature aligns more closely with rural Northern Hemisphere land surface temperature records, suggesting minimal influence from urbanization bias (aka the urban heat island effect). This study demonstrates the suitability of Common Yew for dendrochronology and dendroclimatology in the Caucasus region.