Epiphytic lichen communities were studied in old coniferous forests across Estonia to find out the effect of site openness on the lichen species richness. All lichen species were recorded on the basal 2 m of 105 Picea abies and 105 Pinus sylvetsris trunks. The canopy openness readings were taken with a spherical densiometer around every sampled tree. The number of species on the trunks of both tree species increased significantly with increasing canopy openness. Nine lichen species, e.g. Cladonia cenotea, Lecidea nylanderi, Platismatia glauca, were significantly favoured by higher light availability, and only one species, Coenogonium pineti, by lower light availability. The results demonstrate that in the coniferous forests higher light availability supports higher species richness of epiphytic lichens on the lower trunk of trees.