This study aims to determine forest sites using direct, indirect and remote sensing (RS) methods (Landsat 7 ETM+ and IKONOS images) for Ardahan-Yalnızçam Forest of 12149.23 ha with 63 sample plots (1637,8 ha). Four different forest site classes of dry, moderate fresh, fresh and moist were determined in direct method whereas three site index (SI) classes; good (SI = I – II), medium (SI = III) and low (SI = IV – V) were determined in indirect method. Forest sites were also estimated with RS method using supervised classification from Landsat 7 ETM+ and IKONOS images respectively with a 0.77 kappa statistic value and 84.4% accuracy assessments; 0.88 kappa statistic value and 90% accuracy assessments. Spatial analysis functions of geographic information systems (GIS) indicated some important differences between the methods were identified in ground measurement area. The forest sites determined with indirect method indicate that SI I – II cover 213.27 ha, III 600.57 ha and IV – V 502.93 ha and, treeless areas and degraded forest areas 328.67 ha. Whereas direct method defines dry site of 597.35 ha, moist site of 49.86 ha fresh site of 266.06 ha and moderate fresh site of 724.5 ha. Landsat 7 ETM+ classifies dry site of 353.21 ha, moist site of 261.03 ha, fresh site of 479.93 ha and moderate fresh site of 543.6 ha; IKONOS classifies dry site of 284.25 ha, moist site of 307.45 ha, fresh site of 333.01 ha and moderate fresh site of 713.06 ha.
Keywords: forest site classification, geographical information systems, GIS, site index, direct method, Landsat 7 ETM+ – IKONOS satellite image, Turkey