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ŠUMARSKI LIST 5-6/2014 str. 51     <-- 51 -->        PDF

DROUGHT IMPACT ON FOREST TREES IN FOUR NATURE PROTECTED AREAS IN SERBIA
UTJECAJ SUŠE NA ŠUMSKO DRVEĆE U ČETIRI ZAŠTIĆENA PRIRODNA PODRUČJA U SRBIJI
Horák, Rita, Borišev, Milan, Pilipović, Andrej, Orlović, Saša, Pajević, Slobodanka, Nikolić, Nataša
Summary
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.
Key words: climate change, water deficit, beech, common spruce, silver fir
INTRODUCTION
Uvod
Main elements of global climate change are temperature increase, rise of atmospheric CO2 and redistribution of precipitation patterns which at some sites lead to more frequent drought occurrence during the vegetation season. Change of all this elements at a global level dictate an increase in their variability at a local level on specific sites (Schär et al., 2004).
Elevated atmospheric CO2 levels can have stimulative effect on plant productivity. However, prerequisite for such model is a sufficient water supply in the root zone (Brouder and Volenec, 2008). Forests are noted as an important terrestrial carbon sinks that partially compensate global increase of atmospheric CO2. Increased CO2 assimilation by forests is predicted to be especially significant in the first half of the 21st century (Woodward and Lomas, 2004; Schulze et al. 2010). Global rise in temperature can act as a stimulator of photosynthetic processes and determines a shift of forest species toward higher mountain altitudes (Saxe et al., 2001;