KUŠNIEROVÁ, A: Phenological studies on vegetative (leaf) organs of manna ash (Fraxinus ornus L.). [Diploma thesis] – Technical University in Zvolen, Faculty of Ecology and Environmental Sciences, UNESCO Chair on the Ecological Awareness and Sustainable Devewlopment. Thesis supervisor: Assoc. Prof. Ing. Branko Slobodnik, PhD. Degree of professional qualification: Engineer, abbreviation: ,,Ing.”. Zvolen: FEE TU, 2021, 73 p. On the locality Radvaň – Vartovka, the spring vegetative phenophases of manna ash (Fraxinus ornus L.) were observed from April 8 (initial bud burst) to May 29 (fully developed leaves in all individuals), 2020. In the same year, the autumn vegetative phenophases were observed between September 24 (initial leaf coloration) and November 12 (total loss of leaves in all individuals). The non-flowering individuals were characterized by a very slight time advance in the onsets of both spring and autumn vegetative phenophases. In 2020, the total length of the vegetation period represented 161 days. As it follows from the comparison of our data with the results of previous monitoring of the same locality (2014 – 2019), in 2020 the initial dates of individual spring vegetative phenophases were near to the several-year means. Regarding the autumn vegetative phenophases, only the onset of the general leaf fall was the latest in 2020. The initial dates of the spring vegetative phenophases correlated with the mean temperatures in previous winter and early spring closer than with the corresponding precipitation. The high mean temperatures in winter and spring months accelerated the onsets of the spring vegetative phenophases. Contrariwise, the influence of precipitation on individual spring vegetative phenophases was more controversial. The initial dates of spring vegetative phenophases were most influenced by temperature and precipitation in October. While the higher October temperatures accelerated the onsets of autumn vegetative phenophases, the higher October precipitation caused their delay.