The subject of the diploma thesis is the observation of the variability of the undergrowth in communities of oak forests depending on the structure of tree storey. Research was carried out on five established spots of Fageto-Qercetum slant sites on the volcanic mountains Kremnicke vrchy and Javorí. Observation of the herbarium was carried out during the vegetation period in June 2017 and dendrometric quantities were measured in September / October 2017. After the terrain measurements were completed, data were processed by the software programs JUICE 7.0, Statistica© and CANOCO. Changes have been recorded in the coverage of the herbage area; especially the numbers of E1 species in the spots were captured. From the herbage significantly succeeded the beech species as: Galium odoratum, Dentaria bulbifera and mesotrophic Melica uniflora. The tree layer differed in particular by the number of trees and the size of the circular base (cm2). In the relationship between the herb layer and the tree layer, it was found that the herb layer is most affected by the coverage of shady trees and the average age of the sub-level.