In order to evaluate environmental factors limiting distribution of species, diversity of epiphytic lichens was studied in 34 sites along an altitudinal gradient from 1300 to 1900 m on north-facing and south-facing slopes of Elmali Cedar Research Forest (Antalya province, Turkey) regarding the dispersion of lichens in different tree-diameter classes (0-15 cm, 15-30 cm, 30-45 cm, 45-60 cm and > 75 cm). The results showed that the relationship between diameter classes with the number of lichen species was R-2=0.6022. The highest number of species was in the diameter class of 30-45 cm. There was a clear relationship between all parameters, diameter, attitude and aspect, with species richness. Changes in the community structure of the epiphytic lichen vegetation were detected along an altitudinal gradient revealing the highest species richness in the highest zone. The elevation affected both the number and the composition of the lichen communities and the relationship between the altitudinal zones with number of lichen species was designated as R-2=0.6462. The number of species was higher in the north aspects then in the south aspects in all diameter classes. The species number depending on the altitude was also higher in the north-facing slopes than in the south-facing slopes.