The palaeoclimatic potential of recent oak tree-ring width chronologies from southwest Ukraine

Better insights into spatio-temporal climate signals are needed to understand more clearly the applicability to palaeoclimatic analysis and dendrochronological dating of the long tree-ring oak chronologies currently being compiled in Eastern Europe. This study investigates the climate sensitivity of two recent oak tree-ring width (TRW) chronologies from Transcarpathian and Ciscarpathian Ukraine and their coherence with 35 oak chronologies from Ukraine, Poland, Slovakia, Romania, and Hungary. The new Transcarpathian chronology consists of 247 TRW series of living trees from 13 sites covering the period 1836-2020, while the new Ciscarpathian chronology consists of 215 TRW series from 13 sites and spans the period 1775-2020. Despite the strong similarity between these two chronologies, their responses to climate differ significantly. Growing-season precipitation and particularly drought (three-month SPEI index) were found to be the primary drivers of oak growth on the border between the Carpathians and the northeastern Pannonian Basin. Spatial correlations of the Transcarpathian chronology show particularly high explained variability in the April-August SPEI index, roughly between 18.5-28.5oE and 45-52oN. In the Ciscarpathian, June precipitation primarily influenced oak radial growth but the spatial correlation was quite low. While the Transcarpathian TRW chronology was strongly correlated with eastern Slovakian and northwestern Romanian chronologies, the Ciscarpathian chronology revealed very low correlations with surrounding chronologies. This study indicates the great dendroarchaeological and palaeoclimatic potential of the Transcarpathian chronology and points to the need to analyse additional living trees from the Ciscarpathian region to understand the spatial variability of oak growth and its climate signal better.Preprin

Modelling forage potential for red deer: A case study in post-disturbance young stands of rowan

Recently, the red deer (Cervus elaphus) population has increased considerably and caused serious damage in forest stands in Slovakia as well as in other Central-European countries. Rowan (Sorbus aucuparia L.) is the tree species that is most intensively browsed and stripped by deer, especially during young stages of tree development. Our research focuses on estimating rowan mass consumption by red deer in young stands which developed after large-scale wind disturbance that occurred in the Tatra National Park in 2004. New models were developed for estimating the mass of tree components that are potentially edible by red deer using tree-base diameter as an independent variable. The results showed that the mass contribution of particular tree components to accessible deer forage depended on tree size (tree-base diameter). At stand level, total forage potential increased with an increase in tree size. However, whereas the quantity of bark available for stripping increased with tree size, the total mass accessible for browsing (leader shoot and branches with foliage) decreased. For instance, the contribution of stem bark to total forage potential in stands with a mean tree-base diameter of 20 mm and 50 mm was 15% and 50%, respectively. Theoretically, if all tree mass potential is consumed by red deer, young rowan stands (considering tree coverage of 50%) growing within an area of 100 m2 might provide sufficient forage for one adult deer for ca. 10 days. It is suggested that rowan species should not be removed from forest stands in territories with a high deer population in order to decrease the potential damage of other, commercially important, tree species.</p