Soils, microclimate and vegetation differed greatly between 2 contrasting NE- and SW-facing slopes in the Appalachian Mountains of E Kentucky [USA]. Silt loam Shelocta soils had developed on the NE slopes, while sandy loam Rigley soils had developed on the SW slopes. Air temperature, through-fall, soil temperature and the annual cycle of soil temperature fluctuations were all significantly greater on the SW than on the NE slope. Available soil moisture and relative humidity were greater on the NE slope. Vegetation of the NE slope was more diversified in numbers of species and tended towards the mixed mesophytic type including yellow poplar, basswood and cucumber magnolia. The SW slope supported a less diverse plant community with mixed oak and hickory as the dominant trees.