Leś. Pr. Bad., 2009, Vol. 70 (4): 339–354.

Przebudowa drzewostanów z wykorzystaniem naturalnych procesów sukcesyjnych
w Puszczy Białowieskiej
Stand conversion by means of natural succession in the Białowieża Primeval Forest
Rafał Paluch¹, Kamil Bielak^2
1Instytut Badawczy Leśnictwa, Zakład Lasów Naturalnych, 17-230 Białowieża,  Fax +48 085 681 2203, e-mail: R.Paluch@ibles.waw.pl
²Szkoła Główna Gospodarstwa Wiejskiego, Wydział Leśny, ul. Nowoursynowska 159, 02-786 Warszawa
Abstract. The objects of the research were stands aged 60 years and older with birch or aspen (pionier species) in the proportion equal or higher than 30%. The research was conducted in 40 randomly selected stands growing under the site conditions typical of the fresh mixed deciduous forest (LMśw) and the fresh deciduous forest (Lśw) in the Białowieża Primeval Forest.
The main species in the examined stands growing in the mixed deciduous forest are spruce (36%), birch (29%), hornbeam (12%) and oak (10%). The average share of other tree species does not exceed 5%.
In the fresh deciduous forest site type the major role is played by hornbeam (32%) followed by birch (26%), while the share of spruce and oak is markedly lower accounting for merely 15% and c. 10%, respectively. In the mixed deciduous forest site type the species composition of every fifth examined stands is similar to that of the target forest (GDT), 40% of stands partially comply and 40% of stands do not comply with the species composition model.
Only 5% of stands growing in the fresh deciduous forest site fully meet the requirements of the GTD model, the species composition of 40% of stands partially comply and 55% of stands largely depart from the model.
An analysis of the species composition of stands with regard to their compliance with the species composition of natural communities shows that in both investigated forest site types only 10% of stands feature a significant lack of compliance with the stand composition model.
Hornbeam is the dominant species in the regrowth and undergrowth layer of the examined stands. The natural regeneration of other tree species is significantly limited.
The obtained results of the research point to the possibilities, purposefulness and need to use natural succession in forest practice. In fact, the transformation of transition stands in the Białowieża Primeval Forest has, to some extent, been completed in a natural way. Silvicultural measures should consist in the regulation of species composition adjusted to the conditions in each stand.

Key words: forest site type, species composition, pioneer species, transition stands.