The article provides a brief overview of epiphytic moss diversity on the main stand-forming tree species - spruce (Picea spp.), aspen (Populus tremula), and birch (Betula spp.), in southern Karelia. The list includes 60 species for which information about the location, habitat, and type of substrate is presented. Comparison with checklists from other regions suggests the epiphytic bryoflora of the middle taiga subzone in Karelia has been revealed quite fully. The highest species diversity of epiphytic mosses was found on aspen - 56 species; 20 and 18 species were recorded from birch and spruce, respectively. Common species in the epiphytic cover on aspen trunks are Amblystegium serpens, Brachythecium salebrosum, Dicranum scoparium, Hylocomium splendens, Lewinskya elegans, Nyholmiella obtusifolia, Plagiomnium cuspidatum, and Pleurozium schreberi; for birch - Dicranum montanum, D. scoparium, Hylocomium splendens, Plagiothecium rossicum, Pleurozium schreberi, and Sanionia uncinata; for spruce - Dicranum scoparium, Hylocomium splendens, Plagiothecium rossicum, and Pleurozium schreberi. Among the listed species, 2 mosses are included in the Red Data Book of Karelia (Neckera pennata and Nyholmiella gymnostoma), and 11 mosses (Eurhynchiastrum pulchellum, Eurhynchium angustirete, Homalia trichomanoides, Isothecium alopecuroides, Mnium stellare, Neckera pennata, Nyholmiella gymnostoma, N. obtusifolia, Plagiomnium drummondii, Pylaisia selwynii, Ulota intermedia) are considered as indicators of biologically valuable forest communities. Obligate epiphytic moss species in the middle taiga subzone of Karelia are Lewinskya elegans, Neckera pennata, Nyholmiella obtusifolia, N. gymnostoma, Pylaisia polyantha, P. selwynii, and Ulota intermedia.