British Columbia Reference Page
Western Redcedar (Thuja plicata)
In 1987, the British Columbia Tree Council was formed to choose an official provincial tree. They considered the distribution and characteristics of various tree species. They examined the roles various trees have played in British Columbia’s culture, history and economy. And they listened to private citizens and read essays from school children.
Finally, they chose the western redcedar, and it was adopted in 1988. British Columbia’s provincial tree is not a true cedar and should be spelled redcedar, not “red cedar.”
Redcedars grow in a variety of moist habitats in coastal and interior British Columbia. It is a lighter green than most conifers and is easily identified by its long, sweeping branches that are covered by drooping branchlets, or fronds, which give it a lacy, misty appearance. Its form is like that of a spire.
Native Americans had many uses for redcedars. They made dwellings from its wood and baskets from its roots. They even made clothing from redcedar bark!
Today, the tree’s aromatic wood is used in interior decoration and furniture, for siding on buildings, and for roofs. Redcedar wood is also used in making “cedar” chests.
The western red cedar (Thuja Plicata Donn) was adopted as the official tree of the Province on February 18, 1988. Historically, the tree has played a key role in the lives of west coast Indians, and continues to be a valuable resource for the Province.
Millions of homes have been built with Western Red Cedar, because this wood is very lightweight and easy to finish. Western Red Cedar is also a natural insulator. The wood is used for all purposes where durability and ease of working are of primary importance. It is especially useful for caskets and coffins, siding, tank stock, porch columns, hothouse construction, boatbuilding (the planking of racing shells), and also for interior finishing. Western Cedar is also frequently used for veneer, both for faces and backs, especially in the manufacture of exterior siding.
The Western Red Cedar is a softwood tree found primarily through the upper coastal ranges of western Canada and the United States from Alaska south through British Columbia. Some trees are also found in Washington and Oregon and east to Idaho and Montana.
Nature’s practically perfect wood
Western Red Cedar is nature’s most practical, most versatile wood. There’s a grade, size pattern and product for just about every job whether outdoors in the garden or indoors in the home.
Long lasting good looks
Cedar’s natural preservative oils deter attack by insects and decay. It’s one of the world’s most durable woods. And it’s dimensionally stable, naturally resistant to splitting, cupping, and warping. With proper finishing and maintenance, cedar keeps its good looks far longer.
Prestige and added value
Western Red Cedar delights the eye and evokes admiration. It reflects good taste while adding prestige and value to homes of any style.
The beauty of cedar
There’s no substitute for cedar. It’s real wood with all of wood’s inherent fragrance, charm, color tones and grain texture. Cedar’s beauty complements any home.
Ten Ways Better
Western Red Cedar
From Northern British Columbia, Canada, to California, a rugged spine of mountains stretches for almost 1,500 miles parallel to the Pacific coast of North America. Along the slopes and in the valleys of these mountains, the humus-rich soil nourishes mixed softwood forests in vast abundance.
The majority of Western Red Cedar (Thuja plicata) grows in coastal forests. Western Red Cedars grow also in the drier interior forests of British Columbia, Washington, Idaho and Montana where they are smaller in stature with a tight knotted growth characteristic. Cedars rarely grow in pure stands but are generally found in association with other species. Western Red Cedar forests are predominantly managed forests, in which controlled harvests, natural regeneration and reforestation programs ensure a perpetual harvest.
A Wood Of Warmth And Beauty
Western Red Cedar is, above all, a wood of exceptional beauty. In its natural, unfinished state, it has a richly textured, tactile grain combined with a palette of warm, mellow tones ranging from light amber to deep honey brown. No man-made material can duplicate the depth of cedar's natural luster. It also remains subtly aromatic, and the characteristic fragrance of cedar adds another dimension to its universal appeal.
Whether used in wall paneling or ceilings, doors or windows, mouldings, railings, or posts or beams, the presence and prestige of cedar enhances structures of any type or design, contemporary or traditional, homes, offices, stores or public buildings.
The Gift Of Durability
Western Red Cedar contains natural oils that act as preservatives to help the wood resist insect attack and decay. Cedar is also a dimensionally stable wood that lies flat and stays straight. Properly finished and maintained, Western Red Cedar ages gracefully and endures for many years.
Cedar is the preferred material for all outdoor applications that seek visual harmony with the landscape combined with stability and durability: from siding and patio decking to fences, planters, screens, shelters and garden furniture. Indoors, cedar's dimensional stability makes it perfectly suited to a variety of uses in high moisture areas such as kitchens, bathrooms and saunas.
Western Red Cedar should be preservative treated if intended for use in applications where it comes in contact with the ground.
Beauty aside, the purely practical, dollars-and-cents value of cedar offers other benefits: the wood's cellular structure creates interior air spaces that give it an insulation value higher than most woods and much higher than brick or concrete. Buildings which feature cedar paneling, ceilings or siding tend to stay cooler in the summer and warmer in the winter. Cedar also has excellent sound suppression and absorption qualities.
A Wood For Craftsmen
The same structure that gives cedar its excellent insulating and sound suppressing qualities makes it a lightweight wood, easy to handle and install for both the professional and do-it-yourselfer. Cedar is a pleasure to work using either hand or machine tools. The wood can be cut, shaped, planed, sanded, nailed and glued easily. It is free of pitch and resin and it finishes to a richly glowing surface that can be enhanced with transparent or full-bodied stains or with paints.
Western Red Cedar - Mt. Maxwell Provincial Park
Circumference - 26' 3"
This is the largest western red cedar I know of on Salt Spring. It is located in Mt. Maxwell Provincial Park. The largest western red cedar in BC was discovered in 1988 and is located on the east shore of Cheewhat Lake, Vancouver Island. Its circumference measured 62 feet, 0 inches.
Western Red Cedar
(Thuja plicata) grows mostly in coastal forests from Northern California to Southwest Alaska. The same species also grows in the drier interior forests of British Columbia, Washington and Idaho. It is a wood of exceptional beauty and unmatched durability, yet an unknowing buyer can easily become lost in Cedar's many specialty products and grading rules. The Western Red Cedar Lumber Association and its member mills have established new industry standards for the purpose of making Cedar products easy to specify for an intended use by the consumer. These products are valued primarily for their appearance. Therefore, Cedar grading rules are based on appearance more than on structural strength.
Because of regional differences in soil and climate conditions, Western Red Cedar can have varying characteristics. This is important to know when choosing products made from Western Red Cedar. The large old-growth trees found in British Columbia yield clear heart-wood, which is used to make clear bevel siding - the most prized, (and the most costly), Cedar product. But, these trees also have a high amount of shake, rot, splits and large knots. Young-growth Cedar, found mostly in Washington State, has less clear heart-wood, but contains more material suitable for tight knot sidings. It has a lighter, more uniform color than old-growth Cedar and its knots are small and intergrown with the surrounding wood. Young-growth cedar has the added advantage of being renewable.
Western Red Cedar (Thuja plicata) is one of North America's great renewable resources. Slow growing and naturally durable, Western Red Cedar has one of the longest lifespans of any North American softwood. It produces long lengths of timber with true, straight grain. It is free from pitch and its heartwood has natural decay resistance. Its low density gives it an insulation value superior to most other species. Light weight, easy to work, easy to finish, possessing outstanding dimensional stability, Western Red Cedar is a preferred wood for nearly all purposes where attractive appearance or resistance to weather is important.
|Acoustic properties:||Cedar tends to dampen sound transmission|
|Density (12% mc):||23 lb/ft3|
|Specific gravity (12% mc):||0.34|
|Fasteners:||Corrosion-resistant only (aluminum, hot-dipped galvanized, brass, silicon bronze, stainless steel)|
|Finishing:||Paints, stains, varnishes, oils and waxes all work well|
|Flame spread rating:||69 (Class II)|
|Smoke developed classification:||98|
|k value (12% mc):||0.74 BTU in/ft2 hｰF|
|R value:||Nominal lumber thickness/k value|
|Stability:||Cedar is the most stable softwood species|
|Workability:||Easy to cut, saw, nail and glue.|
One of the lightest commercial softwoods, the density of Western Red Cedar at 12% moisture content is approximately 23 pounds per cubic foot with a relative density (specific gravity) of 0.34. The density of oven-dry material is 21 pounds per cubic foot. Comparative oven-dry densities of cedar and some other softwood species are given in Table 1.
Like all woods, Western Red Cedar is hygroscopic and will absorb or discharge moisture to attain equilibrium with the surrounding atmosphere. However, it has a very low shrinkage factor and is superior to all other coniferous woods in its resistance to warping, twisting and checking. The size differential between dry and unseasoned Western Red Cedar is given in Table 2. Shrinkage in both the radial and tangential directions is given in Table 3.
Wood is an excellent thermal insulator. This is an important characteristic since good thermal insulators help keep buildings cool in the summer and reduce heating costs in winter.
The conduction of heat in wood is directly related to its density. Woods with low density have the highest thermal insulating value because such woods contain a high proportion of cell cavities. In dry wood, these cavities are filled with air which is one of the best known thermal insulators.
With its low density and high proportion of air spaces, Western Red Cedar is the best thermal insulator among the commonly available softwood species and is far superior to brick, concrete and steel. It has a coefficient of thermal conductivity (k value) at 12% mc of 0.74 BTU in./ft2h ｰF.
R values for Western Red Cedar can be calculated using the following formula:
|t = nominal lumber thickness in inches|
|k = thermal conductivity value|
An important acoustical property of wood is its ability to damp vibrations. Wood has a cellular network of minute interlocking pores which converts sound energy into heat by frictional and viscoelastic resistance.
Because of the high internal friction created by the cellular pore network, wood has more sound damping capacity than most structural materials. Floor, ceiling and wall assemblies of wood can provide effective economical sound insulation and absorption when properly utilized. Western Red Cedar is particularly effective in this regard and can be used to help reduce noise to confine it to certain areas.
Flame Spread Rating
Flame spread ratings describe the surface burning characteristic of interior finishes. They are used to regulate the use of interior finish materials to reduce the probability of rapid fire spread. Materials are burned in a test furnace for a relative assessment of flammability. The lower the flame spread rating, the more the material resists the spread of fire.
Building codes in North America generally define as interior finish any exposed material that forms part of the building interior. This usually includes interior wall and ceiling finishes, flooring, windows, doors and other wood products. U.S. codes set the maximum flame spread for interior wall and ceiling finishes in most buildings at 200. The flame spread rating for Western Red Cedar is 69 (Class II rating).
Smoke developed classifications reflect the amount of smoke released by a burning material. They are used in conjunction with flame spread ratings to regulate the use of interior finish materials where the potential to generate smoke or control smoke movement is of major fire safety importance.
U.S. codes set the maximum smoke developed classification for interior wall and ceiling finishes in most buildings at 450. The smoke developed classification for Western Red Cedar is 98.
Western Red Cedar's flame spread rating and smoke developed classification compare well with the ratings of many other species, both softwood and hardwood. Because of its favourable fire performance, Western Red Cedar can be used for interior finishes in some building applications where other species would not be permitted.
Historically, native peoples of the Pacific coast prized cedar for its long lasting qualities and used wood and bark from cedar trees for most of their building needs. Evidence of cedar's durability are the many cedar artifacts still in good condition today.
Properly finished and maintained, cedar will deliver decades of trouble-free service. If exposed for prolonged periods to conditions where decay could be a factor, such as where the wood is in contact with the ground, cedar should be treated with suitable wood preservatives.
Western Red Cedar has good fastening properties but its natural preservatives have a corrosive effect on some unprotected metals in close contact, causing a black stain on the wood. Fasteners should be corrosion-resistant such as aluminum, brass, silicon bronze, hot-dipped galvanised or stainless steel.
Nails and screws used to fasten Western Red Cedar should be about one-third longer than those used to fasten hardwood species.
Because it is free of pitch and resin, Western Red Cedar has excellent gluing properties, comparable to those, for example, of old growth Redwood and American Chestnut. It works well with a wide range of adhesives.
Although cedar is a naturally durable species, leaving it untreated is not recommended because a finish or protective coating will greatly increase its service life. Cedar is free of pitch and with its high degree of dimensional stability, it is the best of the softwoods for accepting paints, stains, oils and other coatings. For further details, see General Information on Finishing Western Red Cedar.
With its straight grain and uniform texture, Western Red Cedar is among the easiest and most rewarding woods to work with. It takes a fine finish in all hand and machine operations, takes fasteners without splitting and is easily sawn and nailed. When working with Western Red Cedar, sharp cutters are recommended.
Table 1. Comparative Softwood Densities (pcf)
|Western Red Cedar||21|
|Douglas Fir (Coast)||32|
Table 2. Size Differential Between Unseasoned and Dry Lumber
|Nominal Dimension (in.)||Size Differential Between Unseasoned and Dry Lumber After Surfacing (in.)|
|1-1/2 or less||1/32|
|2 to 4||1/16|
|5 to 7||1/8|
|8 or more||1/4|
Table 3. Shrinkage of Western Red Cedar
|Direction of shrinkage||Shrinkage in Percentage|
(25% or greater moisture content) to:
(15% average moisture content) to:
|Notes to Table 3:|
|1.||Radial shrinkage applies to the width of vertical grain lumber; tangential to the width of flat grain lumber.|
|2.||Shrinkage does not begin until the fibre saturation point is reached.|
|3.||15% is the average equilibrium moisture content of wood during the summer in the Pacific Northwest.|
|4.||12% is the summer average equilibrium moisture content in dry areas of the Pacific Northwest.|
|5.||6% is the average equilibrium moisture content for interiors of heated buildings.|
Last Updated 990629