Growing season thermal climate reconstructed at six pine stands in northern Lapland

Abstract

At the northern coniferous timberline of the boreal region, growing season temperature is generally the major environmental factor limiting the growth processes of Scots pine (Pinus sylvestris L.). Variations in annual ring-widths of pines can be related to summer temperature parameters. Models of growth response are used to determine how these trees respond to known climatic conditions. Reconstructions of past summer temperatures are achieved by means of transfer function analysis. The annual increments of tree-rings during their life-span were studied in an area where waether data from meteorological stations could be obtained. Eight areal chronologies were constructed and weather stations at Karesuando, Sweden, and Karasjok, Norway, provided temperature and precipitation records for comparison with the tree-ring time-series. On the basis of response function analysis July temperatures were reconstructed year by year for six areas using tree-rings of pines. A multiple regression model was produced to estimate climate in year t as a function of tree growth in years t and t+1.

Keywords

• paleoclimatology
• paleotemperature
• reconstruction
• tree rings
• Pinus
• Holocene
• Enontekiö
• Utsjoki
• Finland