Without human interference the natural vegetation of this area would consist of woodlands dominated by ash (Fraxinus excelsior) in alkaline areas. Hazel (Corylus avellana) and oak (Quercus petraea) woods would be prominent in the more acidic areas. Nowadays (2014) most of the land surrounding Slievecallan is heathland, pasture and non-native forestry. The forestry is mainly plantations of Sitka spruce (Picea sitchensis)