Differential Responses of Bilberry (Vaccinium myrtillus) Phenology and Density to a Changing Environment: A Study from Western Carpathians.

Environmental factors regulate the regeneration of mountain spruce forests, with drought, wind, and bark beetles causing the maximum damage. How these factors minimise spruce regeneration is still poorly understood. We conducted this study to investigate how the phenology and population dynamics of bilberry (Vaccinium myrtillus L.), a dominant understory species of mountain spruce forests, are related to selected environmental factors that are modified by natural disturbances (bark beetle and wind). For this, we analysed bilberry at different sites affected by bark beetles and adjacent undisturbed forests in the Tatra National Park (TANAP) during the growing season (April-September) in 2016-2021, six years after the initial bark beetle attack. The observations were taken along an altitudinal gradient (1100-1250-1400 m a.s.l.) in two habitats (disturbed spruce forest-D, undisturbed spruce forest-U). We found that habitat and altitude influenced the onset of selected phenological phases, such as the earliest onset at low altitudes (1100 m a.s.l.) in disturbed forest stands and the latest at high altitudes (1400 m a.s.l.) in undisturbed stands. Although there were non-significant differences between habitats and altitudes, likely due to local climate conditions and the absence of a tree layer, these findings suggest that bilberry can partially thrive in disturbed forest stands. Despite temperature fluctuations during early spring, the longer growing season benefits its growth.

The ground-level ozone concentration in forest and urban environments in central Slovakia.

This paper analyses data by summarising the concentration values of ground-level ozone (GLO). The study area is situated in central Slovakia and is part of the Western Carpathians. These measurements were carried out between 2015 and 2020, implementing Werner's method working with passive samplers. The highest average and the highest absolute GLO deposition values were 30.93 ppb and 61.06 ppb, respectively, recorded in August 2015 in the forest in the Kremnické vrchy Mts. The lowest average GLO value in the whole measuring period was 17.72 ppb, measured in the town of Zvolen; the absolute minimum was 4.43 ppb, recorded in April 2016 on an open plot in the Kremnické vrchy Mts. The GLO formation over the study area has not yet reached a steady rate. Since 2007, the developmental trend has been increasing. Statistically significant differences in GLO concentrations were confirmed between the localities with different airborne pollutions. However, the analysis of the existing ozone concentration values showed considerable differences, especially related to the time pattern. The spatial variability was equalised. The extreme values, while remarkable, were dangerous, especially in the forest stands in the Kremnické vrchy Mts., where they were 14 times above the critical level of 32.5 ppb O3. The dominant factor influencing the GLO concentration was global radiation. The effects of average temperature and rainfall total were less important.

The ground-level ozone concentration in beech (Fagus sylvatica L.) forests in the West Carpathian Mountains.

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.