a1 Department of Botany, University of Oulu, Linnanmaa, SF-90570 Oulu, Finland.
Epiphytic lichen communities on trunks of Pinus sylvestris and Picea abieswere studied on a west–to–east gradient through the central pan of Finland with special reference to macrolichens. Comparisons were made between the two conifer species, the coast of the Gulf of Bothnia and the more continental inland area, open commercial and denser natural forests differing in their local climate, and tree bases (0·0–0·7m) and upper trunks (0·7–2·0m). Differences were found not in species composition but in relative species abundance, the main distinction being between the two tree species. There were also noticeable geographical, vertical and habitatdependent differences. In addition to climatic factors, the importance of bark properties for the epiphytes is briefly discussed.
(Accepted August 04 1990)