From Silvics of North America:
Incense-cedar (Libocedrus decurrens) is the only species from the small genus Libocedrus that is native to the United States. Increasingly, it is placed in a segregate genus Calocedrus. Incense-cedar grows with several conifer species on a variety of soils, generally on western slopes where summer conditions are dry. It is long-lived and grows slowly.