Vegetation and land-use in the Småland Uplands, southern Sweden, during the last 6000 years

Detta är en avhandling från Quaternary Sciences

Sammanfattning: Palaeoecological methods were applied to peat and sediment cores recovered from one bog (Bråtamossen) and two lakes (Avegöl and Femtingagölen) in the Småland Uplands, southern Sweden. The general aim was to reconstruct the landuse and vegetation history for the last 6000 years in this agriculturally marginal region. The main technique was pollen analysis, which was complemented by mineral magnetic measurements and lithological characterisation. The results from the different sites were compared with each other and with local archaeological information. The study provides information on the regional development as well as differences and similarities within the region. Relatively small basins were studied so that the pollen diagrams and other results mainly reflect the local development around each site. Working at this spatial scale facilitates a comparison with archaeological data. The first agrarian land-use is dated to 3900 cal BC. From that time onwards, through the Neolithic and the Early Bronze Age, the area was used for wood pasturage. The first major deforestation was carried out during the Late Bronze Age and the Early Iron Age. The timing of this agrarian expansion differs somewhat between the three sites, but a common feature is that it resulted in a semi-open pastoral landscape during the Roman Iron Age and the early Migration Period (c. cal AD 0-500). Hordeum and Triticum were grown, probably in a system of shifting cultivation. An agrarian regression at c. cal AD 500 resulted in reforestation of abandoned pastures. In areas at high altitudes (Bråtamossen, Avegöl) cereal growing ceased and grazing pressure decreased. Grazing pressure decreased also in the valley at Femtingagölen, but some cereal growing may have persisted there. There was an agrarian expansion and deforestation at all sites at AD 1000 1400 (Middle Ages). It resulted in a diverse cultural landscape with pastures, hay meadows, permanent arable fields and some slash-and-burn cultivation. In late Modern Time several types of land-use, for example slash-and-burn cultivation and traditional hay production, have ceased and coniferous forest has expanded at the expense of open land. The Picea invasion AD 900 1200 resulted in a major change of the forests. This was the only dramatic environmental change, in the period studied, that was not a direct result of human activity. Pinus was the only tree that expanded at the same time as Picea, and the vegetation changed from a deciduous to a coniferous forest. There has also been a long-term change in forest composition during the last 5000 years, which may be described as a gradual change from a nemoral to a boreal forest. A detailed comparison with a pollen diagram from southernmost Skåne, and a more general comparison with 20 pollen diagrams from sites in or close to the Småland Uplands, show a complex and diverse landscape development. The thesis is based upon four papers which are included as appendices.

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