Past millennium hydroclimate variability from Corsican pine tree-ring chronologies

Palaeoclimatic evidence is necessary to place the current warming and drying trends of the Mediterranean region in a long-term perspective of pre-industrial variability. Annually resolved and absolutely dated climate proxies that extend back into medieval times are, however, limited to a few sites only. Here we present a network of long ring width chronologies from Pinus nigra tree-line sites in northern Corsica (France) that cohere exceptionally well over centuries and support the development of a single high-elevation pine chronology extending back to 974 CE. We apply various detrending methods to these data to retain high-to-low frequency ring width variability and scale the resulting chronologies against instrumental precipitation and drought observations to produce hydroclimate reconstructions for the last millennium. Proxy calibration and transfer are challenged by a lack of high-elevation meteorological data, however, limiting our understanding of precipitation changes in sub-alpine tree-line environments. Our new reconstructions extend beyond existing records and provide evidence for low-frequency precipitation variability in the central-western Mediterranean from 974–2016 CE. Comparison with a European scale drought reconstruction network shows that regional predictor chronologies are needed to accurately estimate long-term hydroclimate variability on Corsica.