Relevance of element content of bark for the distribution of epiphytic lichens in a montane spruce forest affected by forest dieback.

Element content in the bark on Norway spruce (Picea abies) was measured in a montane forest heavily affected by forest dieback and compared to that in a nearby intact stand. Bark contained less S, K, Fe, Mn, Pb, Cu, and H+ and more N, Ca, Mg, and Zn in the dieback-affected stand than in the intact one. Diversity of epiphytic lichen vegetation was higher in the dieback-affected stand than in the intact one. Cover of the foliose lichen Hypogymnia physodes was negatively correlated with Mn and Cu content of bark. Cover of the extremely acidophytic species Lecanora conizaeoides decreased with increasing Mg and increased with increasing Cu content of bark. The measurements support the hypothesis that chemical site factors are decisive for the high lichen diversity in dieback-affected montane spruce forests.