Range expansion of thermophilic aspen (Populus tremula L.) in the Swedish subarctic

In subarctic Sweden, recent decadal colonization and expansion of aspen (Populus tremula L.) were recorded. Over the past 100 years, aspen became c. 16 times more abundant, mainly as a result of increased sexual regeneration. Moreover, aspen now reach tree-size (>2 m) at the alpine treeline, an e...

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Bibliographic Details
Published in:Arctic, Antarctic, and Alpine Research
Main Authors: Van Bogaert, Rik, Jonasson, Christer, De Dapper, Morgan, Callaghan, Terry V
Format: Article in Journal/Newspaper
Language:English
Published: 2010
Subjects:
Earth and Environmental Sciences
EUROPEAN ASPEN
NORTHERN SWEDEN
BOREAL-FOREST
RECENT CLIMATE-CHANGE
TREE-LINE AREA
BIRCH FOREST
ENVIRONMENTAL-CHANGE
OPEROPHTERA-BRUMATA
EPIRRITA-AUTUMNATA
SCANDES MOUNTAINS
Antarctic and Alpine Research
Arctic
Northern Sweden
Subarctic
Online Access:https://biblio.ugent.be/publication/1056951
http://hdl.handle.net/1854/LU-1056951
https://doi.org/10.1657/1938-4246-42.3.362
https://biblio.ugent.be/publication/1056951/file/6743404
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Summary:In subarctic Sweden, recent decadal colonization and expansion of aspen (Populus tremula L.) were recorded. Over the past 100 years, aspen became c. 16 times more abundant, mainly as a result of increased sexual regeneration. Moreover, aspen now reach tree-size (>2 m) at the alpine treeline, an ecotone that has been dominated by mountain birch (Betula pubescens ssp. czerepanovii) for at least the past 4000 years. We found that sexual regeneration in aspen probably occurred seven times or more within the last century. Whereas sexual regeneration occurred during moist years following a year with an exceptionally high June July temperature, asexual regeneration was favored by warm and dry summers. Disturbance to the birch forest by cyclic moth population outbreaks was critical in aspen establishment in the subalpine area. At the treeline, aspen colonization was less determined by these moth outbreaks, and was mainly restricted by summer temperature. If summer warming persists, aspen spread may continue in subarctic Sweden, particularly at the treeline. However, changing disturbance regimes, future herbivore population dynamics and the responses of aspen's competitors birch and pine to a changing climate may result in different outcomes.

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