Western Red Cedar

Thuja plicata

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Basic Information


Habit: Shrub/Tree

Leaves: Leaves are scale-like, decurrent, opposite in 4 ranks, each leaf green, glabrous, 1-6 mm long including decurrent base (shortest at tips, longest at base of shoot), acute to abruptly acuminate, often mucronate; stomata forming an irregular patch on the lower side of each leaf.

Inflorescence: male and female cones with ten to twelve scales

Flowers: cones

Fruit: 3 seeds beneath each scale

Habitat: Partially shaded areas where soil is rich and water is abundant

Range: USA: Alaska, Montana, Idaho, Washington, Oregon and California; Canada: British Columbia, Alberta; at 0-1500 (2000) m elevation.

Enthobotanical Uses

As one of the most common trees of the northwest, Red Cedar is a keystone species both historically and in the modern world. To the Native Americans of the Pacific Northwest, Red cedar was used in every aspect of everyday life. Whole trees could be used as dugout canoes, bark was used for clothing, wood for housing, and roots for sewing. Natives also had countless medicinal uses for the tree as well. Depending on the geography, different tribes used different parts of the tree to cure common ailments such as the cold and sore throat, and even diseases as dangerous as tuberculosis. It was also believed by many that Red Cedar could ward off evil spirits. When a person of outstanding character passed away, legend said that a cedar tree would grow from the place he was buried to help his people after he has died. Surprisingly, very few trees were chopped down before European expansion in the west. Native peoples would instead salvage fallen logs or cut bark and planks from living trees.

In modern day society, Western Red Cedar continues to play a major role in the timber industry. It provides a soft but durable wood that can be used for building houses or making shingles. It is also valued as an ornamental tree in gardens.


Red Cedar is monoecious which means it has both male and female cones on the same tree. Male cones tend to be nearer the bottom while the female seed cones are farther up and away from the trunk. Pollination occurs around March/April and major seedfall occurs around October and November. Surprisingly, even thought it is one of the most common trees in this area, seedlings have a relatively high mortality rate. If seedbed quality is not optimal, germination is unlikely to take place. Red Cedar requires abundant nitrogen, calcium, and water in order to thrive. Almost no germination will occur after the first year, so correct temperature and soil quality is critical to the formation of a seedling. Rotten wood that is in contact with the soil provides optimal conditions for germination. Partial shade is also critical as high soil temperature and low moisture will damage the young trees. The roots of the Red Cedar seedlings grow slowly in comparison to Douglas Fir or Incense Cedar, however they make up for it in shoot growth. During the first five years in coastal areas, a Red Cedar will outgrow Douglas Fir (Pseudosuga menzeisii), Western Hemlock (Tsuga heterophylla), and Sitka Spruce (Picea sitchensis). Red Cedar are also able to partake in asexual reproduction. In some areas, clones from fallen branches that have taken root outnumber seedlings that have germinated.

Interesting Facts

  • The Heartwood of Thuja plicata produces tropolones which make it extreemely decay resistant and also contribute to the distinctive smell of these trees.
  • This species can live up to 1000 years and grow up to 200ft!
  • It is the official tree of British Colombia
  • A tree in the Olympic National Forest was cored and provided a ring count of 1460 years


Forager Foundation, "Western Red Cedar-Thuja Plicata". http://www.foragerfoundation.org/native-seeds/western-redcedar-thuja-plicata. Retreived June 2015

Plantwise Knowledge Bank, "Plantwise Technical Fact Sheet: Thuja Plicata". http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=53789. Retrieves June 2015

Earle Christopher J. The Gymnosperm Database, "Thuja plicata". http://www.conifers.org/cu/Thuja_plicata.php, (2015). Retrieved June 2015

USDA Forest Service, "Western Redcedar", Publications Vol 1 "Silvics of North America". http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/thuja/plicata.htm. Retrieved June 2015

Photo#1: www.foragerfoundation.org , http://www.foragerfoundation.org/native-seeds/western-redcedar-thuja-plicata

Photo#2:www.cnr.uidaho.edu, http://www.webpages.uidaho.edu/for320/Gymnosperms/Cupressaceae/Thuja%20plicata/Thuja%20plicata.jpg

Photo#3: www.conifers.org, http://www.conifers.org/cu/Thuja_plicata.php