Ongoing climate change has been causing major existential as well as productive changes to some forest ecosystems. In the context of the emerging aridization of the climate in Central Europe, especially during the growing season, it will be necessary to consider tools for adapting forests to climate change, in particular the gradual change of the composition in order to increase the species diversity of forest stands. A change in the composition of stands should lead to an increased abundance of woody species better tolerating drought and high temperatures, especially at a lower altitude. Fir is one of the woody plants that could help to solve the situation. The aim of this work was to evaluate the prospect of silver fir growth in Slovakia as well as to more comprehensively determine the variability of physiological parameters of contrasting provenances. Measurements were carried on two contrasting provenances of white fir originating in Poland and Austria, but growing in the same plot Hertník in Slovakia, to see how they react to the change. Two measurements were conducted in July and September and we followed primary and secondary phases of the photosynthesis. For assessing of the primary phases the parameters of rapid chlorophyll a fluorescence were used (maximum quantum yield, number of active reaction centers and performance index). Gas exchange parameters (such as total assimilation rate, stomatal conductivity and transpiration rate) were measured for evaluation of the light independent reactions. We measured all photosynthetic parameters under different conditions (July and September), therefore we can compare the response of contrast provenances to drought stress. We found significant differences between provenances in all mentioned physiological parameters at least in one term. In general, the Austrian provenance AT showed the highest values in all of the monitored gasometric and fluorescence parameters and thus achieved the highest photosynthetic performance. We can say that the assimilation rate is also dependent on the efficiency of the primary phase of photosynthesis as it depends on how much light-energy is captured and converted into energy usable for plants. We confirmed no significant differences between provenances in growth characteristics.