EN
The purpose of the research was to study some of the features of silver birch, in its habitat conditions, as a naturally occurring pioneer crop appearing in open spaces formed by the disintegration of the Norway spruce monocultures in the Silesian Beskid Mountains. On the three research plots the occurrence of the young natural regeneration and understorey of 13 species of trees and shrubs was determined. On the basis of the number of specimens it was found that the most dominant species in the whole area was Norway spruce (56-64%). Birch accounted for 14-16%, and all pioneer species (Betula pendula, Populus tremula, Pinus sylvestris, Salix caprea, Sorbus aucuparia) accounted for 21-23%. However, the researched plots are generally covered by birch due to the share of this species amounts to nearly 90% in the height classes above 0.5 m. The birch appeared within 4-6 years of the disintegration period of the spruce stand. The succession of the birch, its quick growth and ability to develop a crown confirm the possibility of using this species as a pioneer crop. Climax species (silver fir and common beech) can be introduced to a seven-year-old birch pioneer crop, depending on the birch vitality, with the assumption of the conversion period of 30 to 40 years. In the case of the birch vitality abatement the suggested period of conversion will have to be shortened.