Response of Picea abies populations from elevational transects in the Polish Sudety and Carpathian mountains to simulated drought stress

The response of 24 Norway spruce populations from a broad elevational gradient to four combinations of watering and temperature was studied in a phytotron experiment. The results of this experiment are important for better understanding possible impacts of global warming on low- and high-altitude populations of Picea abies. The investigated populations showed evidence of clinal variation in height, mass and bud-set parameters in all treatments. The higher the elevation of origin, the earlier the bud-set and the poorer the mass and height of the populations. The interaction of population origin x treatment showed a small percentage variance component, but there was a clear differentiation in reaction of the tested populations to the simulated drought. The low-altitude populations showed a strong negative reaction to the drought stress, whereas the high-altitude ones were more drought tolerant. So if global warming would be accompanied by soil drought, the low-altitude populations would reduce their growth much more than the high-altitude ones. But if global warming would be combined with an adequate increase of precipitation, then low-altitude populations would profit from this climate change more than high-altitude ones. (C) 2002 Elsevier Science B.V. All rights reserved.