American mountain ash (Sorbus americana) and American holly (Ilex opaca) generally occupy separate ranges in North America. Their domains, however, converge in the Southern Appalachians, where the two trees exhibit an interesting duality along the mountain slopes.
Mountain ash is found along the highest peaks, while holly is abundant farther downslope. Both trees, though, are generally absent in a belt between 3,000 to 4,000 feet in elevation. A familiar feature of the mountain South is the archipelago of Canadian “islands” along the spine of the Appalachian range. Peaks and ridges above 4,000-5,000 feet have climate and vegetation very similar to that of southern Canada and northern New England. American mountain ash (Sorbus americana) is a typical northern species also native to the highest reaches of Southern Appalachians. It shares a habitat with red spruce and Fraser fir. The plant is also known as the “rowan tree,” a name apparently borrowed from the European mountain ash (Sorbus aucuparia), a species with similar characteristics. The Scandinavian word rowan means ‘red,’ referring to its bright berries. Roan Mountain, on the North Carolina-Tennessee border, supposedly received its name because of the numerous native rowan trees growing near its summit.