Accumulation of Ct and Nt in humus and mineral soil layers: the effect of change of tree species composition in nudal beech forests

English. The effect of change of tree species composition on the content of carbon and nitrogen in surface humus and mineral soil layers was studied in the Kremnické vrchy Mts, in the phytocoenoses of forest type group Fagetum pauper. Research was conducted in six forest stands, which represented the natural mature beech stand and five changed stands – birch, spruce, larch, pine and beech pole stage. The research results showed that change of tree species composition had a partial influence on the content of Ct and Nt in soil layers of analyzed phytocoenoses. It was reflected the most in surface humus and topsoil 0–5 cm layers. The highest Ct content was found in surface humus of coniferous stands

in the case of Nt it was in humus horizons of deciduous trees. In the mineral soil layers significantly higher contents of Ct and Nt were found in coniferous stands, in comparison with deciduous stands. Forest stands with changed tree species composition showed a higher content of studied elements in humus horizons as well as in mineral soil layers. In deciduous stands higher C/N ratio was found in mineral layers in comparison with coniferous stands. Stands with changed tree species composition had higher C/N ratio in the subhorizons Ool, and towards to the depth profiles it decreased. Statistically significant differences were found out only in the 0–5 cm soil layers.