Atlantic white cedar is one of only six species in this genus. Only three of the six are native to the continent, and two of them are west coast species. This leaves Atlantic white cedar as the only representative in the East, where it occurs in a narrow band along the Atlantic coast. Atlantic white cedar is an evergreen with scaly leaves that occur in a flat fern-like appearance. This species usually grows in very dense, solid stands, and has small rounded cones.

Atlantic white cedar can be confused with arborvitae (commonly called northern white cedar (Thuja occidentalis)) which also occurs in the region where the ranges overlap in New York and New England. In Atlantic white cedar, the evergreen leaves are paired and have short points on the tip. Arborvitae has leaves that are more rounded-appearing to the naked eye but also have short points when viewed closely or with a lens. Arborvitae has cones of similar size but are more elongated than those of Atlantic white cedar.

Atlantic white cedar is adapted to acid (pH 5.5 or lower), wet, lowland sites within 200 feet elevation of sea level. The growing season is about 140 days or longer. The habitat of this species is very limited, and increasingly rare due to coastal development. Associated trees include red maple, black gum, white pine, hemlock, gray birch, and pitch pine. Associated shrubs include lowbush and highbush blueberry. The great range in latitude that white cedar occupies (from Maine to Florida) helps account for the broad species association.
Arborvitae has a much broader longitudinal and elevational range, and is adapted to soils that are slightly acid to alkaline. Arborvitae grows on upland and lowland sites, and in areas with growing seasons as short as 30 days up to 200 days. Both species can be grown on wet, lowland sites with moderate acidity. (2)

Ancient white-cedar logs buried in swamps have been mined and found well preserved and suitable for lumber. Pioneers prized the durable wood for cabin logs, floors and shingles. During the Revolutionary War, the wood was burned for charcoal for gunpowder.

This species is a highly preferred food of deer during winter stress periods. It can easily be browsed out as seedlings or saplings with extensive damage done.

Due to the dense stands which white cedar often creates, it should not be surprising that 8-9 million seeds per acre may be disbursed in a decent seed crop. These seeds are winged and very light, and may be carried long distances by strong winds. Seed dormancy is common and seed can remain viable in the forest litter for many years. Light and moisture are required for germination to occur, and continuous moisture appears to be mandatory. Seedlings grow to saplings at the rate of about 12 inches per year on favorable sites with open but moist conditions. Seedlings are very vulnerable to crowding from other species.

White cedar seedlings are not commonly grown in the nursery, so little is documented about the size and age of transplants. It is likely that the 1-0 class would be preferred as bare-root stock. White cedar has a shallow root system, so suitable planting sites must have abundant moisture very close to the surface.

Site selection is critical to the success of white cedar. Moisture must be reliable, and competition from other species must be controlled. The site must also have protection from high winds or else severe wind-throw will result. Fire will readily kill white cedar if it gets into the crowns. Finally, heavy ice and snow will often break or topple young trees. Deer will preferentially browse white cedar. Beaver presence favors white cedar as deciduous species are preferentially cut by them, leaving the cedar saplings or poles. (2)

Common names:

• Atlantic white-cedar   (Source: Trees US )
• Atlantic white-cypress   (Source: Monog Cupressaceae )
• southern white-cedar   (Source: Trees US )
• white-cedar   (Source: Trees US )
• white-cypress   (Source: Monog Cupressaceae )

Economic importance:

• Environmental: ornamental   (fide Dict Gard; Eur Gard F)
• Materials: wood   (for furniture fide AH 519)

Native:

• NORTHERN AMERICA
  Northeastern U.S.A.: United States - Connecticut, Maine [c.], Massachusetts,
  New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island
  Southeastern U.S.A.: United States - Alabama, Delaware, Florida [n.],
  Georgia, Maryland, Mississippi, North Carolina, South Carolina, Virginia  (1)

Synonyms:

• Chamaecyparis henryi H. L. Li [≡ Chamaecyparis thyoides var. henryae]
• Chamaecyparis sphaeroidea Spach [= Chamaecyparis thyoides var. thyoides]
• Chamaecyparis thyoides f. andelyensis [= Chamaecyparis thyoides var. thyoides]
• Chamaecyparis thyoides f. variegata [= Chamaecyparis thyoides var. thyoides]
• Cupressus thyoides L. [≡ Chamaecyparis thyoides var. thyoides]