Black alder (Alnus glutinosa Gaertn.) as a pioneer species in regeneration of fresh oak-linden-hornbeam forest (Tilio-Carpinetum typicum Traczyk 1962) in Białowieża Forest (East Poland)

Black alder (alnus glutinosa Gaertn.) is considered a hygrophilous species. The aim of the research was to find out if black alder may play a role of a pioneer species in the habitat of Tilio-Carpinetum typicum Traczyk 1962, i.e. fresh oak-linden-hornbeam forest. The investigation was carried out in Białowieża Forest (East Poland). The vegetation was examined with the Braun-Blanquet (1928) method. Soil diagnosis was based on the analysis of soil profiles and a network of test borings. Ecological differentiation of the phytocoenoses in terms of light, humidity, and fertility factors was analysed by indicator values of vascular plants. Obtained results showed that black alder may play the role of a pioneer species in the habitat of fresh oak-linden-hornbeam forest (Tilio-Carpinetum typicum). This phenomenon may occur on haplic luvisols underlayed with clay, after clear-cuts bigger than 1 hectare. Secondary plant communities with black alder that develop in such conditions reveal characteristics of wet oak-linden-hornbeam forest (Tilio-Carpinetum stachyetosum Traczyk 1962).