Climate and relief properties influence crown condition of common beech (Fagus sylvatica L.) on the Medvednica massif

Sa？etak Background and Purpose: Common beech is a dominant broadleaved tree species in European forests, and also on the Medvednica massif. Since climate is a decisive factor in the development of a certain type of vegetation, it might have an equally important role in its survival. The influence of relief properties on the crown condition of common beech (Fagus sylvatica L.) can also be significant, since beech stands on Medvednica vary in their elevation and exposition. Materials and Methods: Twelve common beech research plots, with complete defoliation data sets in the period 2004–2006 were chosen to represent the variety of environmental conditions present on the Medvednica massif in the western Pannonian region of Croatia. Climate parameters used in the model included annual precipitation (AP), precipitation in the vegetation period (VP), mean annual air temperature (AT), and mean air temperature in the vegetation period (VT). The elevation (EL) of the experimental plots and data from the meteorological station of Puntijarka were used to obtain an estimate of the AT, VT, AP and VP on each research plot. Results: The share of moderately to severely damaged trees (crown defoliation over 25%) was highest in 2004, an expected result of the 2003 drought. This value was significantly higher than in the following two years. The determining climate parameter explaining the changes in defoliation was VP, and the most decisive relief parameter was EL. Defoliation was higher with low VP and higher EL. D was higher predominantly on southern expositions. Conclusions: Climate and relief properties were found to significantly influence the crown condition of beech trees. Although there is a significant positive trend of temperature change on Medvednica, in the period 2004–2006 precipitation in the vegetation period had the dominant effect on the crown condition