Species of tree native to the Appalachian mountain region of the United States, but widely cultivated in Europe, Asia, North Africa, and New Zealand as an ornamental and shade tree. It grows to 24 meters (80 feet) in height and bears long, compound leaves with 6 to 20 oblong leaflets. The fragrant white flowers hang in loose clusters. There are many varieties, some thornless. It has long been used for erosion control and as a timber tree.