The amount of ground-level ozone in beech forests depends not only on the pollution intensity but also on the other environmental factors. This paper presents the analysis of the concentrations of ground-level ozone during the growing season (April-September) of beech trees, which represent the main objects modifying the microclimate conditions inside the forest. The research was localized in the Kremnické vrchy Mountains in Slovakia and realized during the period of 2004-2013. The study was carried out on four research plots with different stand structure which was caused by various intensities of cuts. Our results showed that the maximum concentration of ozone during this period was observed on the plot where the original beech stand (without management intervention) grown-maximal concentration reached the values from 44.0 to 50.0 ppb (in the sub-periods 2004-2008 and 2009-2013, respectively). On the other hand, the minimum concentration, 14.0 ppb, was found immediately after the cutting in 2004 on the plot, where all adult trees were removed. A similar course was found within average values of the ozone concentration on the research plots. Despite the fact that the results did not confirm significant differences among the plots, temporal trend showed an increasing concentration of ozone on all plots during the study period.
Keywords: Beech forest; Carpathian Mountains; Ground-level ozone; Growth phase.