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Kinnikinnick Native Plant Society

Focusing on native plants and conservation in North Idaho

Original Species paper by Lois Wythe  

Western Redcedar
Thuja picata Donn

The Latin name, Thuja picata Donn, refers to a tree having sweet-smelling wood whose leaves are plaited or folded.  

Western Redcedars are heavily buttressed trees 150 feet to 175 feet high, and five to eight feet in diameter, where they have been allowed to remain naturally.  Until this decade, exceptional trees would reach heights of 200 feet, with diameters as much as ten to sixteen feet.

The really large trees are now found mostly in protected reserves and areas.  The center of large trees is usually hollow.  In densely crowded stands, the trees have long, clear trunks.  The narrow conical crown of young trees reaches to the ground, and even in dense stands the lower branches are retained until the tree reaches heights of 50 feet to 80 feet.  In old trees, the crown becomes short and blunt.  On young trees, the slender limbs curve upward, but with age, they swing downward in a long graceful curve.  While diameters of 24 to 40 inches are reached in 200 to 500 years, some of the largest trees are believed to be 800 to 1000 years old.  Latest data available shows the 1979 Idaho champion was 177 feet tall, 680 inches in circumference, with a 9.9 foot crown, and was located on Palouse Road in the Clearwater National Forest.

The strongly aromatic wood is reddish brown when freshly cut, but becomes dull brown with exposure.  It is free from pitch, of medium to course grain, is very soft and brittle, and is unusually resistant to decay and insects.  It scarcely warps or shrinks and the Indians of our area used it for totem poles, canoes, lodges, and teepee poles.

Beautiful, flat lacy sprays of scale-like, bright green leaves and upturned, leathery brown cones are characteristic of this tree.  Glossy above, distinctly darker with fragrant white triangular spots beneath, they remain on the tree about 3 years.

The cinnamon red, fibrous bark is less than an inch thick.  The thin bark is so tough that the Indians peeled strips 20 to 30 ft long from young trees for making baskets, and it was even used for rope or fish line.

One of the most interesting feature of our Western Redcedar is the life cycle of the cones it produces.  In the tree key author Herbert Edlin describes this cycle as follows:  “Thuca cedars bear small, oval, reddish male flower groups, later yellow with pollen, near shoot bases in spring.  Minute female flowers, cone-like green or purple, arise on very short stalks on outer branchlets.  Cones ripen brown leaf-like scales in autumn, then open from tight ovals to spreading clusters.  Tiny brown oval seeds, each with a narrow pale brown wing on either side, escape and are spread by wind.  Seedlings raise two oval seed leaves, then a shoot with simple narrow needles projecting all around.  Adult fern-front foliage first appears on side shoots, usually in the second year.”

These redcedars are the darlings of crafters who use them often in floral crafts and potpourri.  Although the wood of the Thuca redcedars is the valuable economic product, the cones sell from $5 to $10 per pound wholesale, and the green redcedar tips, called “fans” bring an equal price and lend color and scent to floral products.

In some years the cone production is really prodigious. 2000 was a year of heavy cone production, while 2002 produced a lighter crop, perhaps being due to a very dry year.

A household use for redcedar foliage is in the repelling of insects, and cedar chips are a well-known filler for pet bedding.

At the Arboretum we have many handsome specimens of fully mature trees.  An especially beautiful redcedar is at the Arboretum entrance near the log cabin.