A palaeotemperature record for the Finnish Lakeland based on microdensitometric variations in tree rings

• Published in: Geochronometria
• Main Authors: Helama, Samuli, Vartiainen, Matti, Holopainen, Jari, Mäkelä, Hanna, Kolström, Taneli, Meriläinen, Jouko
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Walter de Gruyter GmbH 2014
• Subjects: Fennoscandia; Northern Finland
• Online Access: http://dx.doi.org/10.2478/s13386-013-0163-0

Abstract X-ray based tree-ring data of maximum latewood densities (MXD) was combined for south-eastern Finland. This data originated from subfossil and modern pine (Pinus sylvestris L.) materials comprising a continuous dendroclimatic record over the past millennium. Calibrating and verifying the MXD chronologies against the instrumental temperature data showed a promising opportunity to reconstruct warm-season (May through September) temperature variability. A new palaeotemperature record correlated statistically significantly with the long instrumental temperature records in the region and adjacent areas since the 1740s. Comparisons with tree-ring based (MXD and tree-ring width) reconstructions from northern Fennoscandia and northern Finland exhibited consistent summer temperature variations through the Medieval Climate Anomaly, Little Ice Age, and the 20th century warmth. A culmination of the LIA cooling during the early 18th century appeared consistently with the Maunder Minimum, when the solar activity was drastically reduced. A number of coolest reconstructed events between AD 1407 and 1902 were coeval to years of crop failure and famine as documented in the agro-historical chronicles. Results indicate an encouraging possibility of warm-season temperature reconstructions using middle/south boreal tree-ring archives to detail and enhance the understanding of past interactions between humans, ecosystems and the earth.