Historical legacy of old-growth pine forest in Dividalen, nothern Scandes

Abstract

The Dividalen (Sami: Dieváidvuovdi) valley in Troms county, North Norway, is well known for its old-growth pine forest, a biodiversity hotspot for dead wood-inhabiting fungi and lichens. The majority of the valley is protected within the Upper Dividalen Landscape Conservation Area and National Park. A general conception is that until the mid-nineteenth century when agriculture and forestry entered the valley, the landscape was entirely untouched by man and only used as a pathway for Sami and their reindeer herds on their annual migrations between Sweden and the Norwegian coast. Recent investigations on culturally modified trees and fossil pollen from mires have, however, revealed quite a different story. Sami reindeer pastoralism has affected the vegetation composition from the early seventeenth century to the nineteenth century, and traditional land use should be acknowledged as a long present factor in forming the landscape and cultural heritage. The climatic deterioration known as the Little Ice Age had a severe effect on the pine forest stand structure during the same centuries, forming the culmination of a period of climatic stress initiated already in the thirteenth century. Both long-term cultural and climatic factors are thus important to understand the vegetation dynamics and resulting biodiversity within the protected areas.