The relation between the quality of the epiphytic lichens and the damage class of the trees could be investigated by intensive mappings, which took place in the Klosterreichenbach forest-district, northern Black Forest. In this district the favourable constellation for our investigations were found in the combination of huge forest areas with symptoms if the novel forest decline besides stands, where a local emitter caused classical sulphuric damages. In the surrounding of this emitter a strongly impoverished flora of lichens is paralleled by a high damage class of the trees, caused by the intensive yellowing and loss of needles. In the other areas of the forest-district, which show typical symptoms of the novel forest decline a quantitatively good lichen-flora occurred despite of a high damage class of the stand, but depending on the age of the trees and the altitude of the stand. Some representatives of the there thrieving lichen-flora are very sensitive against air pollution. The results, a good developed lichen-flora in combination with a seriously damaged tree, point against the fact, that air pollution is the only cause for the novel forest decline.