Phenolic Compounds as a Tool of Bioindication for Novel Forest Decline at Numerous Spruce Tree Sites in Germany
Abstract Within a project that applied biochemical criteria to the diagnosis of damage to Norway spruce, 43 sites in western and eastern Germany showing only moderate tree damage were screened for the amounts of methanol soluble phenolic compounds in spruce needles. The concentrations of most of the main compounds-especially catechin-positively correlated with needle loss and the altitude of the site. It was also found that it is necessary to differentiate between trees younger and older than 60 years of age. The correlations between the increase of the phenolic compounds studied and the needle loss or the damage class are stronger in the younger trees, possibly implicating differences in …