Właściwości gleby pod okapem czterech gatunków drzew leśnych po 30 latach od ich posadzenia na dwóch różnych siedliskach

The main objective of this study was to demonstrate a relationship between the direction and effectiveness of impact of particular tree species on soil properties and the initial site fertility. The studies were conducted on two neighbouring experimental plots with different forest site types (fresh mixed coniferous forest – BMśw and fresh mixed deciduous forest – LMśw). The analysed species Norway spruce (Picea abies L. Karst.), European larch (Larix deciduas Mill.), Douglas fir (Pseudotsuga menziesii Franco) and penduculate oak (Quercus robur L.) were planted in three replications on 400 m2 plots. It was stated that: 1) the humification processes ongoing under the canopy of the analysed tree species are, to a large degree, determined by the type of forest site; 2) under the same tree species the content of calcium and nitrogen in the nitrate form was found to by markedly lower in the BMśw forest site; 3) in the BMśw forest site, the pH and electrolytic conductivity of the soil under the majority of the analysed tree species were lower; 4) the degrading impact of coniferous species on soil was noticeably stronger on the poorer BMśw forest site.