Anthropogenic use of fire led to degraded scots pine-lichen forest in northern Sweden

Hornberg G., Josefsson T., DeLuca T., Higuera P., Liedgren L., Ostlund L. & Bergman I.
24: 14-29
Northern pine-lichen forests are generally regarded as natural ecosystems that, in the past, were repeatedly affected by wild fires. This paper presents and tests a new hypothesis that reindeer herders used recurrent fires to promote and sustain reindeer lichen-dominated ground vegetation, in order to maintain good winter-grazing grounds in Scots pine forests. We investigated vegetation and fire history in three pine-lichen forests along the Lulealven River in northernmost Sweden. Methods included analyses of pollen, spores, charcoal and soil nutrient capital, coupled with investigation of written historical sources and previous studies. Results suggest that recurrent, intermediate-interval fires started sometime between the 2nd and 8th centuries CE, i.e. at the same time that reindeer became semidomesticated in this region. Such fires continued until the 18th century, when introduction of active fire suppression reduced the occurrence of fire in the landscape. Repeated burning over this long period eventually depleted the soil-nutrient capital, especially nitrogen and phosphorous, thereby severely reducing productivity. In the early 20th century, foresters described such forests as degraded. Results of this study add a new dimension to understanding the genesis and history of many pine-lichen forests. They challenge the notion that reindeer herders have been reluctant, in the past, to use fire. Further studies are needed to evaluate whether a similar history can be ascribed to pine-lichen forests in other parts of northern Fennoscandia. (C) 2018 The Author(s). Published by Elsevier Ltd. Fire history, Northern Sweden, Long-term land-use, Reindeer herding, Pine-lichen forest, LAND-USE, BOREAL FOREST, REINDEER HUSBANDRY, NITROGEN-FIXATION, CLADINA FORESTS, HISTORY, CHARCOAL, RECORD, AGE, RECONSTRUCTION
Tuesday, 02 May 2023 13:43