CROWN CONDITION OF NORWAY SPRUCE IN RELATION TO SULFUR AND NITROGEN DEPOSITION AND SOIL PROPERTIES IN SOUTHEAST NORWAY

Atmospheric deposition of sulphur and nitrogen compounds may lead to e nhanced leaching of base cations, accumulation of nitrogen in organic matter, lowered pH and increased concentration of toxic aluminium in s oil, which in turn may affect the vitality of forest trees. A general monitoring of forest condition has been initiated in many European cou ntries, partly in order to reveal stresses caused by acidification. Ho wever,forest condition is also affected by many other factors. This pa per examines a seven-year series of crown-condition data from Local Co unty Monitoring Plots in Norway spruce stands in Norway. Average, time trend and lability variables were calculated for crown density and cr own colour for each plot. Wet deposition of sulphate, ammonium and nit rate for each plot were estimated using data from the national air and precipitation monitoring programmes. Soil data are based on soil samp ling within the plots. The analysis gave no evident support for the hy pothesized negative effect on crown condition from sulphur and nitroge n deposition and related alterations in soil. (C) 1997 Elsevier Scienc e Ltd.