Distribution and frequency of 11 cyanobacterial lichen species on Populus tremula trunks were studied in the mountain taiga of the North Urals. Within an area of 150×200 m, all aspen trunks were registered, and a range of environmental variables (including characteristics of tree stand, herbs, dwarf-shrubs and mosses; 30 variables in total) were noted within a circle of 6 m diameter around each tree. This study suggests the environmental variables to be of small importance for spatial distribution of the lichens on a local scale. However, the abundance of the species was shown to depend on size and vitality of their host trees, reaching maximal values in oldest damaged trees.