The establishment of Fagus sylvatica at the stand-scale in southern Sweden

Pollen analysis was carried our on peat profiles from small forest hollows at four sires in southern Sweden in order to investigate the establishment of Fagus sylvatica at the stand-scale. Viewed on a continental scale the migration pattern of Fagus can be correlated with climatic change, but at finer scales such a correlation is weaker. Ar the stand-scale there are factors other than climate that are crucial for the establishment of Fagus (e.g., disturbance, seed dispersal, human activities). The establishment of Fagus does not show any regional coherence in southern Sweden, and this may imply that climate was not the limiting factor for its establishment. Fagus seeds are highly dependent on ground disturbance for successful establishment. A semi-open cultural landscape may be optimal for Fagus establishment, as cultural activities may create conditions particularly suitable for its regeneration. At two of the studied sites cultural activities probably created conditions that favoured the establishment of Fagus at 400 and 900 BP respectively. At the other sires the local forest stands were relatively unaffected by cultural activities prior to the establishment of Fagus at 950 BP and 1450 BP respectively, where, fires (natural?) or slight human influence were effective. The present-day distribution of Fagus in southern Sweden suggests migration with a discontinuous front and outlying populations, and this model probably applies to its past distribution. This type of migration means that the landscape becomes filled in by dispersal from outlying stands. The timing of stand-scale establishment is then largely influenced by site-specific factors and chance. Fagus may still be migrating northwards in Sweden. It grows well in its outlying area, and it seems that present-day land use, not climate, is the limiting factor for the local expansion of Fagus. The northern distribution limits of Fagus probably still represent an active front, and outlying stands act as 'infection centres'.