This thesis presents results of ecological research focused on vegetation dynamics and phenology of two plant forest communities (Carici pilosae-Fagetum and Dentario bulbiferae-Fagetum) in managed submountain beech forest in the EES Kremnické vrchy Mts. We have determined the status of the vegetation based on the eco-series of research plots, which represent different growth stages of the wood components – natural seedling, thicket stand, pole timber, mature stand. Consequently, various ecological conditions were reflected in the both quantitive and qualitative characteristics of the examined communities. Based on the results we can state, that the plots covered by young stages of the stand (natural seedling and thicket stand) receive significantly more global radiation, specifically photosynthetically active radiation (PHAR) compared to other two plots (pole timber and mature stand) which dense foliage caused lower penetration of global radiation into the stand interior. The results of our analysis (Shannon-Wiener´s index, Sørensen´s index, morfometric analyses as well as bioindicator´s analysis of plant phytocenoses) approve this fact. On the basis of the dates of plant flowering, we have created the curves of flowering. The plant forest communities, which are situated within the plots covered by pole timber and mature stand, have unimodal character with one peak of flowering in the early spring time. On the other hand, the research plots covered by natural seedling and thicket stand have bimodal character with 2 peaks - the first in the spring time and the second one in the summer. The concentration of selected nutrients (potassium, calcium, nitrogen, magnesium and phosphorus) was analyzed for two dominant species of the communities (Carex pilosa and Dentaria bulbifera). We found out that the concentration of nutrients were significantly changed (p<0.05) depending on the selected vegetative and generative phenophases of these species. Also different ecological conditions affected the both concentration of nutrients and its temporal-spatial dynamics in the plant biomass. Phenological research on common beech (Fagus sylvatica L.) pointed the interannual variability of onset of selected spring and autumn phenophases. We focused on the both spring and autumn vegetative phenological phases: beginning of bud-burst, onset of leaf unfolding, full leaf unfolding as well as onset of leaf coloring and full colouring. Furthermore, we found statistically significant relationships (p <0.05) between onset of spring phenological phases and number of chilling days with specific sum of air temperature accumulated till the beginning of the beech bud-burst. The values of correlation coefficients (r) moved from +0.5 to +0.82. On the contrary, the cumulated precipitation (mm) calculated for the period from May to August correlated only moderately with the autumnal leaf colouring phenology (r =0.33, p<0.05). Trend analysis confirmed earlier onset of spring phenophases, while the delay of autumnal phenophases was recorded, so the vegetation period of beech was extended.