Stability of Norway spruce (Picea abies [L.] Karst.) stands in the Beskid Śląski and Beskid Żywiecki Mts. from the aspect of their nutrition status

The aim of the present research was to determine the stability of spruce stands in the areas of threat to forest stability in the Beskid Śląski and Beskid Żywiecki Mts. in the light of their nutrition. In 2002 samples of soil and of one- and two-year-old spruce needles were taken from sample plots representing various degrees of the threat of disintegration to stands. The following factors were determined in soil: reaction, exchangeable acidity, content of exchangeable cations: Ca2+, Mg2+, K+ and Na+ and the total content of macroelements: C, N, S, Ca, Mg, K and Na. Very small amounts of alkaline cations were found in the sorptive complex, present also in the chemical composition of spruce needles where most of the elements under analysis were in the lower zone of the optimum range or below the threshold values. The results of chemical analyses of spruce needles indicate differences in their content in various needle ages and a disturbance of their proportions, particularly of N, S, K to Ca and Mg, in the stands under serious threat of disintegration. They document the upsetting of mineral economy in spruce, which in turn may influence a greater susceptibility of this species to stress factors.