Water stress and its contribution to decline of spruce forest | Stres zo sucha ako faktor podieľajúci sa na odumieraní smrekových porastov

On the present, we can observe the novel forest decline in Slovak forests. The spruce covers more than 25 percent from all species of trees in our land, so this difficulties are more marked. In addition, estimated original composition of spruce in our forests is only 5 percent. Its planting on places out of his optimum included with impact of complex of negative factors causes decline of stands. Global changes of climate and precipitation distribution could be key factor exercises an influencing on predisposition of injury by another - secondary factors. The risk is also increased by major request of spruce for water amount.We present applied methods and sumarize results of our research in this paper. We investigated physiological response of spruce growing in different condition. Three individuals grew inside a stand and their roots were covered by roof constructions, another three sample trees grew inside a stand without our affection (contorol trees). Six spruces grew in severe condition on the south exposed stand border and three individuals were on the north stand border. Parameters of fast and slow phase of chlorophyll a fluorescence kinetics (Fo, Fm, Fv, FvlFm, Area, Fs, ETR) and concentration of pigments were measured during last season. We found this facts: Assimilatory aparatus functioned worst during last sampling and best function was documented during the June was observed. Visual review is not responsible method for detection of health condition of trees. Rate of pigments suggest that trees have redueed foto-protected function. Individuals growed inside a stand are in good condition. Physiological reaction to simulated water stress was not detected. Decline of stands during the winter 2006 and spring 2007 caused that we have to choose new tree samples for our research. We will observe more individuals: all variants by the same way as one year ago, - three spruces with simulated stress on the south stand border, - individuals on the stand of south borther, which will be watered during critical dry period, - three spruces watered inside a stand.We are also planing to monitor gas exchange, fluorescece curves, water potential and content of amino acid proline this year. Also, we will observe all listed parameters for three degrees of water stress for three-years seedlings.