Samples of bulk precipitation, epiphytic moss (H. cupressiforme Hedw.) and phorophyte bark were analyzed for contents of Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, S, V and Zn. These analyses were the basis for a compartment study of the mineral cycling in an epiphytic ecosystem. The conductivity, pH, buffer capacity and concentrations of Ca, K, Mg and Na of Fraxinus excelsior L. and Fagus silvatica L. bark were determined in the traditional way on bark powder suspensions and in solutions in equilibrium with discs of bark surface. The relation between bark properties and input-output of chemical elements to the epiphytic bryophytes was discussed. The differences in the epiphytic vegetation on Fraxinus and Fagus were assumed not to have been determined by the observed differences between Fraxinus and Fagus in properties of the bark powder suspensions, as these were not reflected in the solutions in equilibrium with the bark surface. Comparisons with other Scandinavian investigations on heavy metal contents in epigeic moss were made. It was concluded that the metal contents of epiphytic moss originate mainly from the atmosphere.