The influence of former land‐use on vegetation and biodiversity in the boreo‐nemoral zone of Sweden

Pollen analyses were carried out at two sites with contrasting land‐use histories (in‐field and out‐land) within a single estate. The aim was to distinguish the relative importance of natural processes and cultural influence on the development of vegetation and biodiversity. The estate lies in the boreo‐nemoral zone of southern Sweden, and attention is focused on the distribution of coniferous and deciduous trees. The in‐fields. which lie close to the estate buildings, are currently dominated by deciduous trees, and have a documented history as fields and hay meadows. The more distant out‐lands were primarily used as grazing land in the past, and support coniferous forest at present. The study covers the last 4000 yr, 2000-1000 BC: the out‐lands site supported natural, dense forests consisting of Quercus, Betula, Tilia, Alnus and Corylus. 1000 BC-AD 1100: several events are best interpreted as an increased cultural activity in the area. Agriculture was based on animal husbandry and the recorded cereals probably originate from a kind of shifting cultivation. AD 1000-1800: agriculture intensified on the in‐fields with cereal cultivation of increased importance, while the out‐fields were used for slash‐and‐burn agriculture and forest grazing. The forests became more open in structure but the composition remained unchanged. An increase in Colluna was a possible consequence of over‐exploitation, AD 1800 onwards: the out‐field deciduous forests were rapidly replaced by Picea‐Pinus coniferous forests during the l800's. The in‐fields retained deciduous forest with a continuity of Quercus and other species. There is a close, positive relationship between floristic diversity and cultural influence during the last 4000 yr. A comparison is made with a similar investigation on another estate in the region, revealing small differences between the estates, but striking similarities in the effects of land‐use types on the development of vegetation. The significance of former in‐fields for nature conservation is discussed, particularly as a potential source for increasing the deciduous component in commercial forestry practice.