Thuja plicata: Our Iconic Northwest Native Conifer

By Corinne Kennedy

Western red cedar, with its lower branches removed, in Area D (Aleks Monk)

Western red cedar, with its lower branches removed, in Area D (Aleks Monk)

Western red cedar (Thuja plicata) is a majestic conifer (a “cone-bearing” tree that has needlelike or scalelike foliage, usually evergreen) – and, I believe, the Pacific Northwest’s most important native tree.  Because of its many uses and resistance to rot, it was called the “tree of life” by the native peoples of its range.  Twenty-first century Seattle contains many large specimens, most of them “second growth” (trees planted after the area was logged), including those in the Seattle Japanese Garden (in Areas D, G, ZZE & ZZW).  Fortunately, because some areas of Seattle were not logged, towering “old-growth” trees remain – notably in Seward Park and in West Seattle’s Schmitz Preserve Park.  In his 1989 classic, Trees of Seattle:  The Complete Tree-finder’s Guide to the City’s 740 Varieties, tree expert Arthur Lee Jacobson eloquently captures the essence of this iconic conifer:

“Seattle has only one native cedar, but what a tree!  Abundant, well known, valuable, it’s a living monument to firm, unyielding resolve:  deeply anchored in earth, strongly ascending towards heaven, mocking the might of the wind, resistant to rot, vigorously enduring for untold centuries.”

Western red cedar’s historic role in the Pacific Northwest is, in fact, comparable to that of Japanese Cedar (Cryptomeria japonica) in Japan.  Both were essential to the spiritual and material lives of their area’s native peoples, and were used to construct buildings and household goods.  [See November 2015 blog article on Cryptomeria japonica.]

Our region’s indigenous peoples had many uses for all parts of the tree.  Its rot-resistant wood was easily split, and used for shelter, canoes, carvings & fuel.  The soft inner bark & roots were used for clothing, blankets & baskets, its branches for rope & incense, and many parts for medicine.  Its healing and spiritual powers are still revered.

To the “settlers” who arrived here beginning in the 19th century, western red cedar was most important as a timber tree.  Its soft but durable wood is even now used for producing shakes and shingles, and for all aspects of home & garden construction.  Produced in its heartwood, aromatic organic compounds called tropolones give the wood its remarkable resistance to decay.

Thuja plicata is not a true cedar but rather a member of the Cypress family (Cupressaceae).  It has many common names in addition to western red cedar:  pacific red cedar, native cedar, giant cedar, giant arborvitae, canoe cedar and shingle cedar.

It grows at low to middle elevations from northern California to southeastern Alaska – and eastward to northern Idaho and Montana.  Its primary habitat is moist or wet forests, but it also appears in drier areas, particularly west of the Cascade Mountains.  As a landscape plant, it’s greatly valued for this adaptability to a range of conditions.  Slow-growing, it takes many years to mature, and can reach over 250 feet in height.

Foliage of Western red cedar (Corinne Kennedy)

Foliage of Western red cedar (Corinne Kennedy)

Thuja plicata is usually described as a pyramidal conifer with a buttressed base, a drooping leader, and scale-like evergreen foliage.  The common name red cedar refers to its aromatic reddish bark and wood.  Branches tend to be “J-shaped” – that is, they droop slightly and then turn upward.  Branches and foliage are usually retained to the ground, even with great age.

Scale-like foliage of Western red cedar (Chie Iida)

Scale-like foliage of Western red cedar (Chie Iida)

Its scale-like foliage is a glossy yellowish-green, closely pressed to the stem in an overlapping pattern that’s been described as a “flattened braid.”  The reddish pollen cones are tiny and numerous.  The egg-shaped seed cones are larger, about 4/10 inches long.  Green when young, they become brown and woody, with winged seeds.

We are fortunate that so many of these magnificent conifers remain in our city.  As Jacobson acknowledges, “Seattle is particularly rich in trees first because it has a good climate, then because not all of its old-growth was logged, and finally because it has an enviable and diverse park system.” []

I’m grateful that Juki Iida, who came from Tokyo to Seattle in 1960 to oversee the construction of the Seattle Japanese Garden, allowed these iconic trees to remain.  I’m sure that they’re overlooked by many of our garden’s visitors, but for me they’re essential to the history and spirit of our region.  Echoing the iconic meanings of Cryptomeria japonica, they’re also, I believe, essential to the spirit of the Japanese-style garden that Juki Iida created in this place.

Corinne Kennedy is a Garden Guide, frequent contributor to the Seattle Japanese Garden blog, and retired garden designer.