POKORNÝ RADEK, TOMÁŠKOVÁ IVANA, AČ ALEXANDER: Shi s in spruce and beech fl ushing in the context of global climate change. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 1, pp. 163-167 Bud phenology and development of needle nitrogen content were monitored on Norway spruce (Picea abies [L.] Karst) and European beech (Fagus sylvatica [L.]) trees grown inside glass-domes for fi ve years under ambient (385 μmol(CO 2 ) mol −1 ) and elevated (700 μmol(CO 2 )

more »

... l −1 ) atmospheric CO 2 concentrations ([CO 2 ]). The spruce to beech ratio was 35:65 in both treatments. At the beginning of the experiment mean age of investigated trees was 5 years. Elevated [CO 2 ] was responsible for premature growth of both spruce and beech buds in the E treatment (not signifi cantly, by 3-7 days). Nevertheless the fl ushing of neither beech nor spruce was not signifi cantly hastened in E treatment during the fl ushing within the 5 years. During the second half of fl ushing faster development of terminal beech buds comparing to spruce was found (Chi-square = 65, p << 0.01). While the trajectory of beech buds development proceeded in the lineterminal -apical -lateral, the development of apical and lateral buds in spruce was fi nished before fi nalization of terminal buds development. At the beginning of the growing season the lowest value of nitrogen in spruce needles from E treatment (mean ± standard deviation 1.20 ± 0.18 %) was found. This could be a reason of weak diff erences between A and E treatment in both tree species. Elevated [CO 2 ] acts as growth stimulator but the nitrogen insuffi ciency eliminates a positive eff ect of [CO 2 ]. As the global climate change express itself in many ways and relationship's consequences among plants and/or animals are hard to forecast. elevated [CO 2 ], forest phenology, global climate change, needle nitrogen Address doc. Ing. Radek Pokorný, Ph.D., Global Change Research Centre AS CR, v.v.i.,