ZLV Online

The article presents original research results of the humus form dynamics in the semi-natural European beech stand in the National Natural Reserve Voděradské bučiny, on the School Training Forest Kostelec nad Černými lesy (Czech University of Life Sciences Prague) territory. The accumulation and chemical characteristics of particular humus form layers were studied: dry matter amount, pH, soil adsorption and exchangeable acidity characteristics as well as plant available and total nutrient contents. The humus form sampling took place in four replications by particular humus form layers (L, F, H, Ah), the analyses were performed individually. Sampling was oriented in the stand parts with closed canopy, compared with the state in gaps formed during natural and semi-natural forest regeneration (decay stage of the stand left for spontaneous development). Results confirmed considerable changes of quantity and quality of surface humus in the gaps. The amount decreased by ca 25% several years after canopy opening, especially in the H horizon, the pH, bases content and base saturation increased, as well as the content of macronutrients (with exception of the total calcium). The results described considerable changes of humus forms during the natural and semi-natural forest cycles connected with the stand regeneration.