Abstract
The process of abandonment of arable land seems to be one of the main factors of changes in landscape and soil properties. This problem occurs on nearly 10% of arable land in Poland. The natural aspect of transformation is connected with the entrance of birch trees on uncultivated land and the anthropogenic aspect is associated with pine plantations. In the beginning, the appearance of trees on the former arable land changes soil properties because soil (and plant) is the most dependent component of the natural environment. In this paper, the role of birch and pine was analysed in comparison to arable land, abandoned land without trees and birch tree communities of different age. After the entrance of birch trees, soil profiles were enriched in nitrogen and elements such as aluminium, iron, cadmium, lead, cobalt, zinc, which were moved from the sod horizon of soil or come from the atmospheric load and were accumulated in litter or the humus horizon. Compared to arable land, some elements, e.g. calcium had lower concentration under birch trees. In comparison to cultivated land, birch and pine trees made the soil environment more natural, as expressed in the chemical properties of soil.