Radiocarbon dated Pinus sylvestris L. wood from beyond tree-line on the Kola Peninsula, Russia

Abstract

Radiocarbon dates were obtained from 24 samples of Pinus sylvestris L. (Scots pine) wood recovered from sites beyond the modern conifer tree-line on the Kola Peninsula of Russia. Twenty-one of the samples came from the shallow waters and eroding peats at the edges of two small lakes at 68°439N, 35°109E, located north of the modern conifer tree-line. Three samples came from a small pond located above the modern elevational limits of Pinus sylvestris at 68°259N, 35°199E. The radiocarbon dates indicate that pine trees grew approximately 20 km north of the mapped modern limits of the species from 6680 BP to 3830 BP. Pine trees were also growing some 40 m above their modern elevational limits between 5890 BP and 3450 BP. Nineteen of the samples date from 6680 BP to 5070 BP, suggesting that the density of trees north of the modern tree-line was greatest between 7000 and 5000 BP. The timing of tree-line advance and greatest density on the Kola Peninsula are in agreement with the results of similar studies from northern Fennoscandia which indicate that maximum northern and elevational extension of tree-line occurred between 7000 BP and 4000 BP. The general agreement between tree-line reconstructions suggests that the climatic changes that promoted mid-Holocene tree-line extension along the North Atlantic margins in northern Fennoscandia propagated eastward to the Kola Peninsula. The late timing of initial pine expansion on the Kola and in adjacent northern Fennoscandia remains problematic and may relate to lower winter insolation, temperature regimes in the adjacent oceans or slow rates of migration.

Holocene Treeline History and Climate Change Across Northern Eurasia

“…The radiocarbon dates from the Kola, Pechora, Taymyr, and Lena sites ( (MacDonald et al, 2000), and the oldest samples are relatively young (Ͻ7000 yr B.P.) as compared to sites from the other regions.…”

“…Samples have also been obtained from the Kola Peninsula, where searches were conducted in the shallow waters of small lakes. Two lakes in the birch foresttundra zone (68°43ЈN, 35°19ЈE) provided a series of Pinus sylvestris samples from approximately 25 km north of the mapped limits of the species (MacDonald et al, 2000).…”

“…The types of trees growing in the Scandes Mountains of Sweden during the early Holocene suggest that there may be no modern analogue for the climate of Fennoscandia and the adjacent Kola Peninsula (Kullman, 1998). MacDonald et al (2000) pointed out that winter insolation was lower than present during the early Holocene and that the susceptibility of Pinus sylvestris to desiccation and root damage due to cold winters may have restricted the northward advance of the species in this region. Colder winters might have also benefited the deciduous conifer genus Larix, which had an early Holocene range that included southern Scandinavia (Kullman, 1998).…”

“…Most of the samples are wood which was identified to genus by comparing thin sections to modern reference material. We also include radiocarbon dates for an additional 21 samples of Pinus sylvestris L. (Scots pine) wood found north of the modern treeline on the Kola Peninsula (MacDonald et al, 2000).…”

The distribution of late-Quaternary woody taxa in northern Eurasia: evidence from a new macrofossil database

“…Conversely, under-represented taxa such as Larix may not be detected in pollen records even when present in the vegetation. Macrofossils, on the other hand, provide precise spatial information on the past location of trees and can enhance spatio-temporal reconstructions of the past treeline (see MacDonald et al, 2000b;Edwards et al, 2005).…”