Phenolic Compounds in Needles of Norway Spruce Trees in Relation to Novel Forest Decline I. Studies on Trees from a Site in the Northern Black Forest

Contents of selected phenolic compounds in needles of Norway spruce trees (Picea abies) from the Black Forest were measured using a HPLC-technique elaborated for serial studies in forest decline research. Measurements on needles that were harvested on several dates during two growing seasons gave no hint of seasonal variations in the concentrations of the studied phenolic compounds. Values for picein demonstrate an average decrease in the needles of severely damaged trees compared with the still undamaged ones, but the results are impaired by strong individual variations among the single trees. p-Hydroxyacetophenone was found in only very low amounts showing no constant differences between damaged and undamaged trees. In contrast to that catechin, epicatechin, piceatannolglucoside, and two still unidentified compounds show significantly higher contents in needles of the damaged trees.