Drought impact on forest trees in four nature protected areas in Serbia

Abstract

Important predictions of climate change propose a correlated increase in frequency of extreme temperature and precipitation patterns. Period of extremely low precipitation occurred during the vegetation season of 2011 at four mountain forest localities of the Balkan region. Influence of this extreme event was correlated with photosynthetic and transpiration intensity, and content of photosynthetic pigments in forest populations of beech (Fagus sylvatica L.), spruce (Picea abies (L.) Karsten) and fir (Abies alba Mill) on four sites, with specific locality properties. Significant reductions in CO2 assimilation along with decrease in water use efficiency, were determined by water deficit. It seems that drought occurrence will influence forests in site specific manner, having the most negative impact on forest populations located in the altitude proximity of mountain reefs and peaks. This process leads to decrease in tree mass and reduced forest cover on such sites. Such environmental conditions will lessen possible acclimation of trees to elevated atmospheric CO2 concentration and upward migration to higher altitudes determined by global temperature increase.