Black alder Minus glutinosa ssp. barbata) is an important tree species used in the forest products industry. This study examined site index variations in different locations in the Eastern Black Sea Region of Turkey, where black alder is widespread. Sixty-five samples were taken from pure black alder stands in three areas (Arhavi/Artvin, Akcabat/Trabzon and Espiye/Giresun). The site indices for the sample areas were determined by two methods: the classical site index and the general algebraic difference approaches. In order to determine the properties of the soil from the sample areas, soil profiles were opened and samples were collected from five fixed depths (0-10 cm, 10-30 cm, 30-50 cm, 50-80 cm and 80-120 cm). Spatial properties (slope, aspect, altitude and relief) of the sample areas and a number of soil properties (sand%, silt%, clay%, pH, organic matter and available water capacity) were determined. According to different site conditions, variations in site indices were examined by analysis of variance (ANOVA) and relationships between site factors and site indices were investigated.