Plant Description

Thuja plicata
Western Red Cedar

Family: Cypress (Cupressaceae)

General Description:

This is a very large stature tree, reaching heights up to 200 ft tall, and often developing two main leaders towards the top, giving it an even greater appearance. The base of the trunk often is very large (up to 15'), and branches often droop nearly all the way to the ground. Cascading branches droop down gracefully from the top, pointing back upwards at the tips.

  • erect

  • tree

  • Native

Phenology: Cone production occurs from April to May

The redcedars stands in Montana today are probably relics from a time when the climate was wetter. Some of the oldest specimen, reaching 1000 years of age, may be found in the state-protected grove on Hwy.12 on the Idaho-Montana border or in the wetter ar


The only native cedar in our area. Rocky Mountain juniper (Juniperus scopularum) is superficially similar, but has rounded twigs with small scale-like leaves rather than flat sprays and a distinctive smell and berry like fruits

Did You Know?:

Ecology: These trees have high resin content, and thin bark, making it susceptible to fire. Fortunately, the trees?moist habitat requirement offers it some protection from this danger. They are tolerant of dense shade, and they require very moist soil. Thuja plicata? physiological responses to low soil moisture include low seed and cone yields, and foliage reduction. The oldest needles are dropped each year in large boughs at a time (34). When the tree does not receive enough moisture in a season, it will drop even more needles, a phenomenon known as ?edar flagging?(108). Reproduction is not limited to seeds alone. Western redcedar may drop seeds, which require sunlight from canopy openings to germinate. Open spots may be hard to come by in these dense groves, so another method of reproduction is called layering. In this case, long branches that touch the ground take root, creating small clones of the parent tree (35). Many trees develop a long taproot and associated lateral root system, so that it can access much needed water. Because T. plicata grows in such moist areas, it does not develop such a well-developed root system. Without it, this tree is susceptible to blow down from wind, because, for such a large tree, there is no anchor to hold it to the ground (32). Origin of Name: ?licata?comes from Greek, meaning, pleated, or folded, referring to the scaly leaves. ?rborvitae?translates to tree of life. This name comes from the decks of old exploring ships, in a time where scurvy was prevalent among sailors. Scurvy is a deadly disease that attacks those who are deficient in Vitamin C. When it was found that cedar tea was a good source of the vitamin, the tree was declared ?he tree of life? as it saved many lives on the high seas (35).


Medicinal and Historical uses: Lewis and Clark documented western redcedar in their journals, describing the coastal Indians?deep reliance on the trees (35). It has been found more recently that many different Native American tribes made use of this tree as a medicinal and construction material. An infusion of leaves could be used for coughs and colds. Bark was used as a band-aid or cover poultice. Buds were chewed to ease the pain of a toothache. Other ailments that may have been eased with poultices include heart trouble, swelling, and sore backs. Decoctions have been used for bronchitis and tuberculosis. An infusion could be soaked in to assuage arthritis (26). In the most favorable of sites, trees have been shown to live up to a thousand years (6). If you visit such an old growth cedar forest, there may be trees with very odd shapes to them. These could be survivors from a time when house builders employed special harvesting practices that could remove large planks from these trees in a way that did not kill them (25). Wood from this tree is exceptional for use in handmade goods, due to its easy maneuverability and rot resistance (5).Other uses and products from these trees, both past and present, include baskets, clothing, canoes, ropes, jewelry for dancers in ceremonies, roofing material, storage boxes, bark was shredded and used as a paintbrush or fishing line, inner bark was used as a wick in oil lamps, totem poles, masks, and the Thompson Indians used leaves and twigs to produce green dye. (6, 26).


Many layers of shredding bark are dark reddish-brown in color. Fibers may be peeled off in long strips.

Flowering Months:
  • summer
  • late spring

Cone production is moisture and climate related. Male and female flowers are in separate cones on the same tree. Male cones are roundish, and 2mm long. Female cones are egg-shaped and slightly larger, 8-12 mm long.

Fruit Type:
  • cone

Scaly leaves glandular, 0.1-.25 in long, overlap the twig on both sides. These yellow-green leaves branch in many directions, creating a flattened spray (32).

Leaf Arrangement:
  • opposite
Leaf Division:
  • simple
Leaf Margin:
  • lobed
Leaf Shape:
  • scale
  • widest at middle
Leaf Stem:
  • without stem



Cool, very moist forests and north-facing slopes. May survive in almost saturated soil. In Montana, they are most often found with western Hemlock (Tsuga heterophylla), western yew (Taxus brevifolia), and grand fir (Abies grandsis) (35).

Non-Forest Habitats:
  • disturbed
  • riparian
Forest Habitats:
  • alder-birch
  • cedar-hemlock
  • grand fir
Disturbed Habitats:
  • riparian
  • lake shore
  • moist slopes
  • hardwood forest
  • conifer forest
  • old growth conifer
  • conifer woodland
  • cliffs/rock outcrops
  • Lauren Priestman
  • 26. Harrington,H.D. 1998. Edible Native Plants of the Rocky Mountains. University of New Mexico Press. Santa Fe, NM.
  • 32. Stuckey, M and Palmer, George. . 1998. Western Trees: A Field Guide. Falcon Press. Helena, MT.
  • 34. Kaufman, Peter B.; Cseke, Leland J.; Warber, Sara; Duke, James A.; and Brielmann, Harry L. 1999. Natural Products from Plants. .
  • 35. Habeck, Jim. 2004. Big Sky Sketches: Western Redcedar (Thuja plicata). .
  • 108. Bega,R.V. 1978. Diseases of Pacific Coast Conifers. USDA Forest Service. Agriculture Handbook No. 521.
  • medicinal
  • commercial