Also known as "Southern Balsam," this stately fir, native to the Great Smoky Mountains of western North Carolina and eastern Tennessee, is closely related to its northern counterpart.  Its soft, emerald-green needles with silvery undersides are about three-quarters of an inch in length.  Its bottlebrush texture, sturdy branching, and outstanding needle retention make it a superb Christmas tree whose popularity has grown rapidly in recent years.