Quercus polycarpa Schur is a little known oak species of the Sessile Oak aggregate (Quercus petraea s. lat.). Different habitats were studied using geobiocoenological typology system in order to investigate its ecology. In total, 65 experimental plots were set in forest stands with Q. polycarpa in the main storey in 12 protected areas situated in south-east of the Czech Republic. Ecological conditions, basic tree parameters and representation of Q. polycarpa within other oak species were evaluated on each plot. The mean values of height, height of life crown setting, stem and crown diameter were related to sub-categories of geobiocoenological system and compared by one-way ANOVA and Scheffé post-hoc test. It has been found out that Q. polycarpa grow in a high number in the 2nd altitudinal zone. It often occurs in a variety of habitats with different hydric and trophic conditions. As expected, the lowest values of measured parameters were found in the dry hydric range, this species reaches the highest values in the normal hydric and mesic ranges.
