Thursday, June 23, 2016
Meet the "Atlantic White Cedar" - Chamaecyparis thyoides
The Atlantic White Cedar - Chamaecyparis thyoides is a small cedar with irregular rounded cones. It is also known regionally as the Post Cedar or the Swamp Cedar. It is a member of the Cupressaceae (Cypress) Family. A monoecious evergreen tree that grows to up to 120 feet tall on rare occasions but averages 40-60 feet tall. It generally appears with a single straight trunk and spire shaped crown. The tree mostly occurs in bogs and swamps or in highly acidic soils, they also form pure stands within forests dominated by other species. It appears naturally along the Atlantic coastal plain from Maine to South Carolina and along the Gulf Coast Plain from Florida to Mississippi.
Image Citation: Karan A. Rawlins, University of Georgia, Bugwood.org
The bark is flaky at first becoming a red-brown with age, often furrowing into long spirals with thin peeling strips. The branches become fan shaped sprays with age that are flattened. The leaves are scale like and slightly overlapping often with a small rounded resin gland, the stomata form a white X on the lower surface. The seeds appear in cones, they are rounded but generally not symmetrical. When mature the cones are relatively small only 4-9 mm wide and long. They are either bluish-purple to reddish-brown, glaucous, not very resinous and made up of 6-8 woody scales. The cones mature and open within 1 year, within the cones the seeds occur 1-2 per scale and are 2-3 mm long with a narrow wing. It is monoecious, but the staminate and pistillate flowers are produced on separate shoots. The flowers appear in the summer but are so small they often are unnoticed by the untrained eye, they remain on the tree untill late fall or early winter.
Image Citation: Keith Kanoti, Maine Forest Service, Bugwood.org
The Atlantic White Cedar has become a very popular ornamental, with over thirty cultivars on the market today. The climate throughout most of the range of Atlantic White Cedar is classed as humid but varies widely in all other aspects. It is recommended for hardiness zones 3a-8b. Average annual precipitation needed is 40 to 64 in and is best distributed throughout the year. The frost-free season required for optimum growth is 140 to 305 days. Temperature extremes range from -36° F during Maine's winter to highs of over 100° F during the Summer seasons in the Southern range. It is often times confused with other similar appearance trees such as the Arborvitae (Thuja occidentolis) which also has branches forming fan like sprays and the Port Oxford Cedar (Chamaecyparis lawsoniana) an ornamental found commonly in the East. The wood is very light and decay resistant but has not been logged heavily since the 20th century.