The genesis of two Picea-Cladina forests in northern Sweden

Abstract

1. In northern Fennoscandia a rare forest type, characterized by Cladina species and Picea abies, occurs on dry productive sites outside the range of permafrost but close to the Scandes mountains. 2. We determined the history of vegetation development and disturbance of two Picea-Cladina forests to test the hypothesis that this forest type has a natural origin. 3. We used a combination of several retrospective vegetation history and archaeological methods, i.e. the analysis of pollen, macroscopic charcoal, dendroecological data, written historical sources, maps and ancient remains. 4. The results suggest that the Picea-Cladina forests investigated are not the products of purely natural factors. 5. Under the influence of harsh climatic conditions and anthropogenic impact, mainly by repeated fires, grazing, trampling and probably also selective cutting of Pinus, mixed coniferous forests, dominated by feather mosses and dwarf shrubs, may have evolved into the Picea-Cladina type. 6 Repeated anthropogenic use of fire, already established c. 2000 years ago, may have been used to create lichen-dominated areas, initially to attract game but later to improve winter grazing resources for reindeer. This finding contradicts the general view that Saami nomads did not use fire to alter forest vegetation.