CAUSES OF FLORISTICAL DIFFERENTIATION OF DENTARIO-BULBIFERAE-FAGETUM (ZLATNIK 1935) HARTMANN 1953 AND CARICI-PILOSAE-FAGETUM OBERD 1957 ASSOCIATIONS

Ecological causes of the floristical differentiation of Carici pilosae -Fagetum and Dentario bulbiferae-Fagetum associations have been studie d. Therefore the phytocenological releves and macromorphological, phys ical and chemical properties of typical cambisols were compared on the selected parallel plots. From the geobiocenological point of view, th e both phytocenoses belong to the 3rd forest vegetation tier, mesotrop hic order of geobiocens, group of forest types Fagetum pauper inferior a (in the sense of Zlatnik, 1959) and types of geobiocens Carer pilosa nudum and Dentaria bulbifera-nudum tin the sense of Hancinsky, 1972). These phytocenoses do not differ substantially from each other by valu es of soil reaction and content of available nutrients (pH(H2O) = 5.2- 5.6, pH(KCl) = 4.2-4.6, K-Sch = 290-340 mg.kg(-1), PB-K = 84-85 mg.kg( -1) in topsoil) and neither by their position in the framework of the mesotrophic edaphic-ecological order of geobiocens. Greater difference s were found in values of the soil water capacity in favour of the ass ociation Dentario bulbiferae-Fagetum. It was determined by means of a reduced (by volume of skeleton) soil thickness and of a maximum capill ary capacity of the soils. In comparison with a maximum water capacity of soils situated on the border of segments of the nudal beech forest s and hydrically (even by the growth) limited oak forests of the 3rd f orest vegetation tier tin case of loamy soils 120-150 mm, in dependenc e on a slope orientation) the values determined in a soil of the assoc iation Carici pilosae-Fagetum were only slightly higher (185 mm). Ther efore, it seems that the beech forest suffers from lack of water when the annual precipitations are low. As a result the shading ability of a beech is lowered, the more light demanding tree species (including Q uercus dalechampii) occur in a stand and the sedge-grasses in a herb l ayer.