The purpose of this research was to study the mutual effects of fir decline and deer browsing on tree regeneration in Kočevski Rog. The first part of the study was conducted in an old-growth forest of Rajhenav. The current number of tree saplings and seedlings was compared to the data from 1984. To further compare, an identical study was performed in the fenced areas in the vicinity of Rajhenav forest, where the effect of deer browsing is eliminated. The conclusion is that Rajhenav old-growth forest is under severe selective browsing pressure. The density of fir seedlings is 132/ha, the density of maple seedlings is 212/ha, while the average beech density is 13928/ha. The numbers in fences are significantly different: 8627 beech saplings and seedlings/ha, 4993/ha for fir and 8007/ha for maple. The population density of deer has rapidly increased in the past 50 years and the Rajhenav old-growth forest provides a favorable habitat conditions. The long-term tree species distribution and reduced diversity resulted from species-specific responses to interacting disturbances and environmental factors.