Natural regeneration of Tilia cordata in relation to forest-structure in the forest of Białowieża, Poland

Abstract The history of the forest of Bialowieza is briefly reviewed. The National Park was created in 1923 in the central and apparently least exploited part of the forest. The composition of the forest varies in relation to the nature of the soils. Almost half of the wooded area of the park is occupied by forest composed of Carpinus betulus, Tilia cordata, Quercus robur, Acer platanoides, Ulmus glabra and Picea abies (Querceto-Carpinetum). The structure of this association is illustrated by maps and transects of selected plots. An almost continuous canopy is formed by Carpinus betulus with tall emergent trees of Tilia cordata, Quercus robur and Picea abies. Tilia cordata regenerates freely and there are numerous groups of seedlings, saplings and young trees which are sometimes in gaps but often beneath the main canopy. The origin of the groups is analysed and evidence is presented that those of T. cordata are probably always less than 50 years old. This is in contrast to analyses made by Paczoski (1928a, b, 1930) shortly after the park was established, when trees of T. cordata with trunk diameters less than 0.3-0.4 m were absent. There is now a discontinuity in the distribution of diameter classes in the population. The influence of this change on the structure of the forest is discussed.