DNA studies show that more than half the trees and shrubs in southern Appalachia can trace their ancestry to eastern Asia.
Based on molecular studies of more than 250 species of trees and shrubs from Georgia to Virginia, researchers at Duke University found close ties between East Asian species, such as dogwoods, and species in the southeastern U.S. Forests throughout the northern hemisphere were joined together by the supercontinent Laurasia as recently as 180 million years ago. Then, as the great northern land mass broke into continents, eras of glaciation wiped out various tree species. Forest remnants hung on in China, Japan, small parts of Europe, and Appalachia, which explains the similarity in tree species. The research was published in the American Journal of Botany.