Juniper Publishers - Open Access Journal of Ecology Introduction Natural treelines in high-mountain regions are considered as excellent and broad-scale indicators of biological responses to climate change and variability [1-10]. Since the early 20th century, treelines of different species have advanced by maximum 200-245 altitudinal meters in the Swedish Scandes, while the forest limit has changed substantially less in elevation [3,11]. Treeline is here taken in a broad sense, as the transition zone (ecotone) between the closed forest and the treeline proper, i.e. the highest trees of a specific species, with a minimum height of 2 m. Up to the present most studies have focused on the treeline with this narrow definition, since spatially-precise early 20th century measurements exist from a large area in the Swedish Scandes. Studies of the entire treeline ecotone are constrained by lack of stringent and repeatable old records and the strongly shifting structure and c...
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