The Encyclopedia Americana (1920)/Arbor Vitæ
ARBOR VITÆ (Latin, “tree of life”), the designation of several trees belonging to the family Pinaceæ and allied to the cypress. The genus consists of evergreen trees and shrubs, with flattened branchlets and small, imbricated or scale-like leaves. The common arbor vitæ (Thuja occidentalis) is a native of eastern North America and reaches a height of 50 feet in favorable locations. The cones are small; the young twigs have an agreeable balsamic smell; the wood is soft and light, but tough and durable. The other North American species is T. Plicata, found on the Pacific coast from the region of San Francisco Bay north to Alaska. The Chinese arbor vitæ (T. orientalis) is often cultivated. Its upright branches and larger cones easily distinguish it from the former. It yields a resin which was formerly thought to have medicinal virtues, like the wood and young twigs of T. occidentalis; hence the name — arbor vitæ.