Treeline and timberline dynamics

• Main Authors: Tinner, Willy, Lang, Gerhard, Schwörer, Christoph
• Other Authors: Ammann, Brigitta, Behre, Karl-Ernst
• Format: Book Part
• Language: English
• Published: Haupt Verlag 2023
• Subjects: 580 Plants (Botany); Arctic; Kola Peninsula; Fennoscandia; kola peninsula; Tundra
• Online Access: https://boris.unibe.ch/185297/1/2023_QuatVegeDynEurope_455.pdf; https://boris.unibe.ch/185297/

Polar treeline and timberline Today’s polar treeline runs along the northernmost part of Fennoscandia and further along the northern edge of the Kola Peninsula and the northern Russian mainland. In continental northern Russia the limit of tree growth (>2–3 m growth height) lies only slightly to the north of the Arctic Circle (66°32’ N) and is formed by Picea abies ssp. obovata, while in oceanic Fennoscandia it goes beyond 71° N and consists of Betula pubescens ssp. tortuosa. South of the polar treeline, dwarf shrub tundra, open birch stands and isolated birch and pine forests form vegetation mosaics. These parklands build the forest tundra and are bordered to the south by closed Pinus sylvestris forests that form the polar timberline (or forest limit) between 69° and 70° N. The polar treeline and timberline represent heat-deficiency limits, whereby, as a rough rule, the minimum for the existence of conifer trees (>2–3 m) is assumed to be 30 days per year with a temperature average above 10°C (e.g. Walter and Breckle, 1986). The global polar treeline has also been associated with growing seasons of 90– 106 days and seasonal mean temperatures between 5.1 and 6.9°C, similar to other treeline positions in the world (6.4 ± 0.7°C; Körner, 2012).