EN
The influence of dwarf mountain pine scrub degradation on organic matter transformation was analyzed in this paper. The subject of the research were podzolic soils covered by the scrubs of the dwarf mountain pine without any visible symptoms of degradation, with the dying dwarf mountain pine and with the extinct dwarf mountain pine and successively developing grass. The microhabitat conditions in the degraded ecosystems were conducive to intensified minera- lization with a simultaneous forming of low-molecular humic bonds characterized by significant liability. Because of this a high degree of the humification of the organic matter conditioned by the illuvial character of the fulvic fraction and fulvic acids appeared in the enrichment horizons of the degraded soils. The conditions of humification in the degraded habitats of dwarf mountain pine scrubs lead also to the formation of weakly mature humic acids, characterized by a lower degree of particle internal oxidation especially in the OH horizons.