Thuja occidentalis L.
Coefficient of Conservatism: 4
Coefficient of Wetness: -3
Wetness Index: FACW
Physiognomy: Nt Tree

This is the characteristic tree of “cedar swamps” that occupy hundreds of thousands of hectares of wet ground in northern Michigan, much of it nearly impenetrable, except by the deer for which both shelter and a favorite food are provided. Cedar may be found at least sparsely in almost all kinds of forests, except the driest; on sand dunes, shores, and rock outcrops (especially limestone); along streams, in springy areas. It thrives on calcareous gravelly shores and ridges near Lakes Michigan and Huron in the northern part of the state. Some records from outhernmost Michigan may be of plants spread from plantings.

The youngest seedlings have opposite or whorled flattened needle-like leaves, but the first branches have the characteristic scale-like leaves. The flat unkeeled leaves (i.e., those on top and bottom of twigs in contrast to the keeled leaves straddling the sides) have a ± prominent resin gland near the apex; this is especially evident on the lower leaf.


Alcona County
Alger County
Allegan County
Alpena County
Antrim County
Arenac County
Baraga County
Barry County
Benzie County
Berrien County
Cass County
Charlevoix County
    Including Beaver Island
Cheboygan County
Chippewa County
    Including Drummond Island
Clare County
Clinton County
Crawford County
Delta County
Dickinson County
Emmet County
Genesee County
Gladwin County
Gogebic County
Grand Traverse County
Gratiot County
Houghton County
Huron County
Ingham County
Ionia County
Iosco County
Iron County
Isabella County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Keweenaw County
    Including Isle Royale
Lake County
Lapeer County
Leelanau County
    Including Fox Islands
    Including Manitou Islands
Lenawee County
Luce County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Macomb County
Manistee County
Marquette County
Mason County
Mecosta County
Menominee County
Midland County
Montcalm County
Montmorency County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ogemaw County
Ontonagon County
Osceola County
Oscoda County
Otsego County
Ottawa County
Presque Isle County
Roscommon County
Saginaw County
Sanilac County
Schoolcraft County
Shiawassee County
St. Clair County
Tuscola County
Washtenaw County
Wexford County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. September 30, 2022.