46 species of lichens were collected along the trunk of ten individuals of Populus grandidentata. Seven species, found in more than 50% of the seventy meter-high quadrats, show well defined patterns of vertical distribution when graphed: Caloplaca cerina (60%), Candelariella vitellina (64%), Parmelia subaurifera (80%), Parmelia sulcata (87%), Physcia adscendens (79%), Physcia stellaris (63%), and Xanthoria polycarpa (61%). Spatial separation of species is well developed in four genera, Bacidia, Cetraria, Physcia, and Rinodina.