Finnish supra-long tree-ring chronology extended to 5634 BC

Dendrochronological crossdating was used to expand a pre-existing multi-millennial tree-ring chronology for Finnish Lapland. Twelve tree-ring series from sedimentary archives of five small lakes contributed to the oldest part of the chronology, extending the record to 5634 BC (previously 5520 BC). Today, the chronology is the longest conifer tree-ring chronology in Eurasia. The geologically oldest pine megafossils were found the eastern part of the region, i.e. north-east Finnish Lapland, and this is also where the authors expect that other very old pine megafossils may be found in the future. Cool climatic conditions c.8 ka ago may have prevented pine regeneration in the tundra-forest ecotone. This may explain the practical difficulty of making the chronology longer than its present form in the study region.