Hrastovi gozdovi v severnem delu gorovja Štiavnické vrchy (srednja Slovaška)

The phytosociological research of the oak forest vegetation was carried out in the northern part of the Štiavnické vrchy Mts (Central Slovakia) using the standard Zürich-Montpellier approach. The data set consisting of 41 phytosociological relevés was obtained by the authors in two vegetation seasons in 2008 and 2009. The numerical classification and the ordination methods were applied to determine the main vegetation types and to explain the structure of the vegetation-environmental data matrix, respectively. Four associations within two classes were distinguished: Luzulo albidae-Quercetum petraeae Hilitzer 1932, typical for shallow, mineral-poor and acidic soils, Melico uniflorae-Quercetum petraeae Gergely 1962 occuring on mesic stands with skeletal and deeper soils, Poo nemoralis-Quercetum dalechampii Šomšák et Háberová 1979 developing on moderately canopyopened stands in the submontane belt, Sorbo torminalis-Quercetum Svoboda ex Blažková 1962 growing on moderately acidic substrates in drier regions. The major environmental gradients responsible for variation in forest species composition was associated with soil nutrient and soil reaction following the Ellenberg indicator values as well as the measured environmental variables (C/N-ratio and soil acidity). Special attention was given to the discussion on species composition and site ecology.Fitocenološke raziskave hrastovih gozdov v severnem delu gorovja Štiavnické vrchy (srednja Slovaška) smo naredili po Zürichško-Montpellierski metodi. Enainštirideset vegetacijskih popisov smo naredili v dveh vegetacijskih sezonah v letih 2008 in 2009. Za določitev glavnih vegetacijskih tipov in za obrazložitev strukture podatkovne matrike vegetacijskih popisov in ekoloških spremenljivk smo uporabili numerično klasifikacijo in ordinacijo. Znotraj dveh razredov smo ločili štiri asociacije: Luzulo albidae-Quercetum petraeae Hilitzer 1932, značilna za plitva, z minerali revna, kisla tla, Melico uniflorae-Quercetum petraeae Gergely 1962, ki se pojavlja na mezičnih rastiščih s skeletnimi, globljimi tlemi, Poo nemoralis-Quercetum dalechampii Šomšák et Háberová 1979, ki se razvije v zmerno odprtih sestojih v submontanskem pasu, Sorbo torminalis-Quercetum Svoboda ex Blažková 1962 pa uspeva na zmerno kislih tleh v sušnejših predelih. Glavna okoljska gradienta, ki vplivata na floristično sestavo, sta hranila v tleh in reakcija tal. Odražata se tako v Ellenbergovih indikatorskih vrednostih kot v merjenih okoljskih spremenljivkah (C/N razmerje in kislost tal). Poseben poudarek smo namenili diskusiji o vrstni sestavi in ekologiji rastišč