Människan i urskogen : vegetationshistoria i Hamra nationalpark under 2500 år

Sammanfattning: Pollen analysis of a peat core was used to reconstruct the last 2500 years of vegetation history, with focus on the impact of anthropogenic disturbance, in Hamra National Park, central Sweden. In addition, analysis of pollen in soil samples was performed in an attempt to locate ancient cultivation plots in the National Park. The analysis of the peat core shows a development of the vegetation that can be divided into four stages of different degrees of human impact: A - virgin forest (c. 500 B.C.-A.D. 1300), B - grazed forest (c. A.D. 1300-1600), C - grazed forest with occasional slash-and-burn cultivation (c. A.D. 1600-1900), D - National Park (c. A.D. 1900-present). The analysis of the soil samples locates three patches where cereal cultivation plausibly has taken place. The possibility of combining pollen analysis of a peat core and of soil samples as a means of tracing cultivation in both time and space is discussed. The forest grazing that began in the Middle Ages is interpreted as outland use, and it is possibly indicating a period of settlement expansion in the area. Increasing impact from forest grazing and occasions of slash-and-burn cultivation in the 17`h century suggest that a further expansion of human impact took place, a result which is supported by the historical records of the colonisation in the area by Finnish settlers. The result of the pollen analysis demonstrates that Hamra National Park is not a genuine virgin forest, but rather a forest influenced by human activities, such as forest grazing by cattle and manipulation of the fire regime. One consequence of the present study is that the human influence must be taken into consideration when planning the nature conservation and the management of the National Park.