Sorensen similarity indices of lichen species in Serif Yuksal forest ranged between 0.29 and 0.84. A linear relation was found between species number sum of two lichen populations and their similarity indices. The linear equation is Y = 0.0076x + 0.1467 and the R2 of the equation is 0.2476 which is significant at p < 0.001. There has been identified a linear relation between the average similarity index of the sites and fir participation percentage. The obtained equation is Y = 0,0009x + 0,5271 and the R2 of the equation is 0,2853 which is significant at p < 0.002. In the pure fir stands there has been found a linear relation between the altitude difference and similarity index. The obtained equation is Y = -0.0011x + 0.6962 and the R2 of the equation is 0.1755 which as significant at p < 0.001.