Prediction of the probability of forest decline damage to Norway spruce using three simple site‐independent diagnostic parameters

Abstract

summarySurvey data for Norway spruce (Picea abies I.) trees at 12 different forest sites across Europe have been analysed. Three variables (dry weight/fresh weight ratio differences between current and two‐year‐old needles, ethylene emissions and violaxanthin/antheraxanthin ratios) were found which together show a significant relationship to tree damage in areas affected by forest decline and which are independent of site effects (P < 0.001). Results are also presented that support the contention that atmospheric pollution, especially tropospheric ozone, is the major cause of this problem. After a four‐year fumigation experiment, 12‐year‐old Norway spruce trees showed similar cellular changes as those found in the 30‐to 40‐year‐old trees of the survey affected by forest decline. In the fumigation experiment, these changes were most pronounced in those plants exposed to a combination of treatments including ozone, sulphur dioxide and acid rain. The pollutant concentrations used in the four‐year study were representative of those experienced by trees growing in affected areas.