Reconstruction of long-term successional dynamics of temperate woodland in Bialowieza Forest, Poland

Abstract

1 Biatowieza Forest contains the most extensive stands of old-growth temperate woodland in Europe. It therefore has the potential to provide a model for nearnatural woodland, which is a conservation aim for many sites in western Europe. 2 Pollen analyses from two small hollow sites in the northern part of Biatowieza Forest National Park are reported here. The records cover the last 1200-1500 years. The pollen data of the principal tree taxa were converted into vegetation data using previously published pollen:vegetation correction factors. 3 These data were used to reconstruct long-term vegetation dynamics in the Tilio-Carpinetum and Pino-Quercetum communities that dominate the forest. Changes in forest composition have occurred as a result of both autogenic and allogenic processes. High grazing intensities in recent centuries have been particularly significant, although the forest is often considered to be undisturbed. 4 The larger hollow (site I) initially sampled across Peucedano-Pinetum, Carici elongatae-Alnetum and Tilio-Carpinetum communities. Since 1750, the Peucedano-Pineturn community has dominated, but with an increased Picea component. This has recently been replaced by the Pino-Quercetum community following the reduction of grazing pressure. These recent changes are largely consistent with published successional models for Bialowieza Forest. 5 Site II recorded a relatively stable balance between the Tilio-Carpinetum and Pino-Quercetum communities until 750 years ago. The Tilio-Carpinetum community then expanded. The continued dominance of Quercus in this community is inconsistent with previous models. 6 The long time perspective available with pollen data permits the exploration of forest dynamics beyond the temporal range of existing models for Biatowieza Forest. Comparison of recent and older records revealed that anthropogenic impact on forest composition has been greatest in recent centuries. 7 This investigation highlights the significant role of history in determining forest stand structure and composition.