The history of land utilization in Scandinavia is characterized by two major periods of open landscape. The first one temporal ranged from cal. AD 0-500 and the second one ranged from cal. AD 1200-1900 including the medieval crisis in Scandinavia. Both periods were characterized by animal husbandry and intensive grazing as well as cultivation. However, slash-and-burn-cultivation and hay production on mires and meadows were prevailing during the medieval crisis. These activities significantly altered the concentration of transported organic carbon (OC) from the terrestrial ecosystem to inland waters. Burning and grazing decreased the terrestrial OC and water table, due to reduction of biomass, whereby burning has a greater effect. Biennial scything of mires for hay production reduced the biomass as well, hence resulting in a decreasing water table and peat accumulation. Even though two periods of open landscape has been present in the historical land utilization of Scandinavia, only the latest one resulted in a decreasing OC concentration in surface water in boreal lake. This indicates that especially the slash-and-burn cultivation and hay production on mires are very important components of altering the carbon storage in soils and peat due to lowering the terrestrial OC pool.

This essay discusses the width of the late medieval desertion of farms in Sweden from an archaeological perspective. The object of the essay is to investigate if archaeological investigations and research during the last 10-15 years have changed the view of the late medieval desertion in relation to the Scandinavian research project on deserted farms and villages. The essay also deals with questions on causes to the desertion and when desertion occurred. An ambition of the essay is also to give a general picture of archaeological investigations during the last 10-15 years considering the late medieval desertion. The analyses-material consists mainly of reports from archaeological investigations. Most of the investigations analysed in this essay are investigations of single farms. Because of this it is natural these investigations do not say much about the width of the desertion. As long as an archaeological investigation is not a part of a large project, where the purpose is to show the width of the desertion, one cannot expect that one single investigation will give much information or knowledge about the width. However, if the ambition is to obtain a complete picture of a medieval deserted farm or village, this essay confirms that an archaeological investigation is necessary, willingly in an interdisciplinary cooperation.