In this Bachelor thesis we present interactions between European blackberry (Rubus fruticosus) and ungulates (roe deer (Capreolus capreolus) and red deer (Cervus elaphus)), as an influencing factor on forest regeneration. Based on maps of forest gaps (made with lidar photos of the whole Slovenia) and phytocoenological community Blechno-Fagetum we chose suitable points with the program ArcGIS. We measured faeces pellet on 20 x 10 m sized plots and on 2 x 2 m sized plots we recorded seedlings, blackberry cover and its damage, fern and herbs cover as well as rockiness and woody debris. The seedlings were categorized by tree species, height class and browsing damage. Further regression analyses were performed in Excel and Statistica. We found that the presence of ungulates and blackberry are positively correlated, as ungulates selectively choose better quality food (e.g., blackberry). Habitats suitable for blackberry have lower seedling densities, but they are less damaged. Growing into higher height classes is also more successful. The influences of ungulates and blackberry vary according to the tree species palatability. Palatable species from our case (which are also more shade-tolerant) are more successful in blackberry-friendly habitats than less palatable species.