Atlantic white cedar trees grow slowly and may live for more than 1000 years. The wood is very resistant to decay. Trees buried in peat bogs for decades have been recovered still in excellent condition. One of the largest inland Atlantic white cedar wetland complexes in the world was located along the Wallkill River flood plain in southern Orange County. Originally over 50,000 acres the "Drowned Lands" swamp was almost completely converted to agriculture by the 1970s.
There are 16 existing populations and about half of them are large and protected. The remaining populations are small with usually under 100 trees but some of them are in protected areas. While some small occurrences may still be discovered it is not expected that additional large populations would be found. All of the historical populations have been checked.
Short-term trends are stable with no big changes in existing populations.
In the last 100 years there has been a decline in Atlantic white cedar swamps in western Long Island and the lower Hudson area including the destruction of some very large swamps in Nassau and Orange counties. Many of the remaining swamps are within developed landscapes without large natural buffers.
Some unprotected white cedar swamps are subject to habitat loss by logging and development. Beaver activity may cause high water levels to kill trees.
Trees need to be protected within their wetlands by providing large enough natural buffers to preserve hydrologic régimes and to prevent direct destruction of the swamps and trees.
Chamaecyparis thyoides is found in swamps and ponds, typically at sites with a high water table and deep organic soils. Unlike Northern-White Cedar (Thuja occidentalis), it is not associated with high pH sites or the influence of calcareous bedrock or groundwater. Historically Atlantic White-Cedar swamps covered large areas in the coastal plain and along floodplains.
In New York this species is known only from the Long Island and lower Hudson Valley regions.
This tree is known from all the Atlantic Coast states, and west along the Gulf Coast as far as Mississippi.
Atlantic White Cedar is an attractive, small to medium-sized evergreen tree, its crown generally forming a narrow spire or column shape. The dark, shiny green foliage is arranged into 2-ranked branchlets, and the tiny (2-4mm) scale-like leaves are imbricate (overlapping like shingles), ovate and usually glandular. The brownish-gray bark is divided into long, thin, tight strips. Thecones are glaucous purple or blue capsules, covered by 4 to 6 non-overlapping scales
This species may be identified from either the cones or sterile branches.
Thuja occidentalis has flattened branchlets, its cones have overlapping scales, and it is typically found further inland and north then Chamaecyparis thyoides. Juniperus virginiana has sharp, needle-like leaves, its fruits are fleshy "berries" rather than capsules, and it is usually found in drier habitats.
May be identified all year round.
The time of year you would expect to find Atlantic White Cedar vegetative and fruiting in New York.
Atlantic White Cedar
Chamaecyparis thyoides (L.) B.S.P.
Flora of North America Editorial Committee. 1993. Flora of North America, North of Mexico. Volume 2. Pteridophytes and Gymnosperms. Oxford University Press, New York. 475 pp.
Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.
Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.
Haines, Arthur and Thomas F. Vining. 1998. Flora of Maine. A Manual for Identification of Native and Naturalized Vascular Plants of Maine.
Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.
New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.
New York Natural Heritage Program. 2022. New York Natural Heritage Program Databases. Albany, NY.
Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.
Rhoads, Ann F. and Timothy A. Block. 2000. The Plants of Pennsylvania, an Illustrated Manual. University of Pennsylvania Press, Philadelphia, PA.
Rhoads, Ann F. and Timothy A. Block. 2005. Trees of Pennsylvania. A Complete Reference Guide. University of Pennsylvania Press, Philadelphia, PA.
Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York
Weldy, Troy W. and David Werier. 2005. New York Flora Atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research. University of South Florida]. New York Flora Association, Albany, NY. Available on the web at (http://newyork.plantatlas.usf.edu/).
Information for this guide was last updated on: February 29, 2012
Please cite this page as:
New York Natural Heritage Program. 2022. Online Conservation Guide for Chamaecyparis thyoides. Available from: https://guides.nynhp.org/atlantic-white-cedar/. Accessed July 1, 2022.