In the massif of Žobrák and Suchý vrch in Malá Fatra, there are complexes of natural forests, which are protected by the national nature reserves Šramková and Šútovská Valley. The thesis will be focus on the specific composition of the forest communities and their long-term dynamics in the context of natural disturbances, as well as the possible effect of human activity. The aim of this bachelor thesis is to interpret the long-term dynamics of forest stands, based on dendrometric data. The observed results will be interpreted in the context of actual knowledge about the impact of disturbing factors on forest development. The surveyed results were different in the 28 areas. The trees were weakly disturbed in eight areas, in eight areas there was medium disturbance and seven areas experienced a strong disturbance. After summarizing the results, we conclude that in our case, it is the dynamics of small gaps. As research shows major disturbances began after 1834, the physiological age of beech in the fir-beech forest is about 220 - 250 years, which means, that in the coming years, the process of disintegration of these stands should begin. In conclusion, we suggest that research on these areas be continued and confirmed or refuted our opinion.