Category:
Softwood
Region:
Coast, Interior
Title:
Western Red Cedar (Thuja plicata)
Photo credit: Kristin Charleton, Sundew Media
About western red cedar
Western red cedar is a resilient and versatile species that can be used in a wide variety of exterior and interior building applications. It is one of the most valuable conifers owing to the unique colour, texture and durability of its wood.
It grows at low to mid elevations along the British Columbia (B.C.) coast and in wetter parts of the southern interior. It holds great spiritual significance for Indigenous Peoples along the northwest Pacific Coast. B.C. is the only province that western red cedar grows. The beauty and dimensional stability of its wood make it an important commercial species.
Where it grows
Western red cedar is shade tolerant and grows in areas where the climate is cool, mild and moist, including low- to mid-level elevations along B.C.’s coast and in the interior wet belt near the Columbia and Rocky Mountains.
It is found in uneven-aged, mixed-species stands with Douglas-fir, Sitka spruce, western hemlock, black cottonwood and red alder, and it grows with Englemann spruce and western larch at higher elevations. Growing terrain is characterized by a lush layer of ferns, huckleberries and Devil’s club, with a thick carpet of mosses on the forest floor. Western red cedar has a shallow, wide-spreading and strong root system.
Did you know?
The western red cedar was adopted as B.C.’s official tree in 1988.
Identifiable characteristics
The western red cedar is a medium- to large-sized tree that grows up to 60 metres tall and 2.5 metres in diameter and often lives to 1,000 years. Its trunk tapers rapidly and it has a long, even crown that becomes irregular with age, often with a forked top. The bark is grey and stringy and tears off in long strips on mature trees. Leaves are scale-like, arranged on the twigs in flat, fan-like sprays that emit a distinctive aroma. Seed cones are egg-shaped with several pairs of scales that ripen in late summer and shed during winter. Pollen cones are small and reddish.
Did you know?
The wood of fallen western red cedar trees remains sound for more than 100 years because of its resistance to decay and insect damage. Even after 100 years, the wood can be salvaged and cut into shakes for roofs.
Photo credit: Kristin Charleton, Sundew Media
Squamish Lil’Wat Cultural Centre
| Photo credit: Michael Bednar
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Photo credit: Micael Bedar
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Photo credit: Ainsworth Communications
Western red cedar’s properties
Common uses and applications
Western red cedar is naturally resistant to decay and insect damage, so no chemical treatment is required. Its superior durability, aesthetic beauty and dimensional stability make it an excellent choice for exterior applications in residential or commercial projects. It is used for roof shingles, exterior siding and cladding, decking, weather boarding, portable buildings, poles, posts and fences, and ship and boat building. It is a popular wood for outdoor uses such as greenways, public art, urban parks and landscape design, patio furniture, playground equipment, greenhouses, garden boxes, gazebos, sheds and pergolas.
Western red cedar is an attractive wood for interior applications including sashes, doors and windows, ceiling and wall panelling, and custom millwork. Its dimensional stability makes it perfectly suited for sauna panelling, mouldings and window blinds. It is a good choice for musical instruments due to its superb acoustic resonance properties.
Western red cedar holds important spiritual and cultural meaning for Indigenous Peoples in B.C., and they use it for medicines, essential oils, spiritual ceremonies and other cultural uses. Indigenous peoples use almost every part of a cedar tree. Roots are dried and braided to make hats and baskets. Withes are strong, lightweight and naturally grow in long strands so they are suitable for ropes and lashing. Bark is dyed and processed into thread for mats, clothing, blankets and hats. Bark is also used for ropes, baskets and fishing nets. Dried bark is an excellent tinder for matches and torches. Cedar wood is used for totem poles, carvings, masks and longhouses, as well as canoes, paddles, hooks, spears and fishing floats. Fish are preserved in cedar smokehouses or dried on cedar racks.
Western red cedar is also used by Indigenous people to make bentwood boxes to store food or other goods. The boxes are made from a single cedar plank which is steamed until pliable and then bent. The two sides are pegged together. The boxes are decorated with paint or carvings.
Commercial properties
Western red cedar wood is fairly lightweight, moderately soft and low in strength. It is known for its excellent working properties and its ability to take a smooth, satiny finish with sharp tools. It is relatively easy to work, with good machining qualities. It planes and shapes well and can be sanded to a smooth finish. It glues easily, has moderate nail and screw holding ability, and takes a good finish.
Western red cedar produces thujaplicin, a defense mechanism against rot and fungus. This natural fungicide enables even a dead tree to be a valuable part of the forest. Properly finished, western red cedar products will last for decades, even in harsh environments.
Commercial availability
While western red cedar can be graded structurally under National Lumber Grades Authority (NLGA) grade rules, it is more often graded for appearance and specialty applications such as clears, shop, fence, panelling and siding.
Western red cedar lumber is often sold green due to its unique properties and longer drying times. When dried, lumber is dried according to end-use and customer specifications. Kiln drying inhibits natural staining of the wood, improves its strength and stiffness, enhances its appearance, and increases its resistance to decay and attack by insects.
Western red cedar – physical properties
Specific gravity (12% m.c.)
Compression parallel (Mpa)
Compression perpendicular (Mpa)
Shrinkage (OD = oven dry | air = air dry 12%)
Western red cedar – visual properties
Colour Heartwood Pinkish- or reddish-brown to dark chocolate-brown. On exposure to light, the colour becomes more uniform. Exposed to the weather, it assumes a pleasing silver-grey colour over time. Sapwood Straw coloured. Heartwood / sapwood contrast The sapwood is narrow and distinct from heartwood. Latewood / earlywood contrast The annual growth rings are distinct, defined by narrow bands of latewood. Transition from earlywood to latewood is abrupt in narrow rings and gradual in fast-growing, wide-ringed wood. Grain The wood is generally straight-grained; has a uniform but medium coarse texture. Figure Plainsawn lumber or rotary-cut veneer: distinct, inconspicuous growth ring. Quartersawn lumber or quarter-sliced veneer: faint growth ring stripe. Other: Wood is non-resinous. Knots Medium to large knots. Other Wood of western red cedar is aromatic and is often described as sweet or chocolate-like. Free from pitch and resin.
Western red cedar – working properties
Process Performance Comments Machining Planing Moderate to good Recommended planer settings: 20° hook and 20 kmpi (knife marks per inch). Wood is subject to compression during planing. Must use sharp cutting tools. Wood is somewhat brittle and splintering is common. Turning Medium to low surface quality Common defects: torn out grain. Sawing Easy to work with tools Easy to saw because of its low density. Corrosive properties can be damaging to cutting blades. Boring Good to medium Good boring quality with brad point bits and moderate quality with single twist bits. Mortising Moderate Better mortising quality is found with a hollow chisel mortise. Shaping Good shaping quality Splintering on the end-grain may be an issue. Recommended: the use of a counter piece for end-grain shaping. Veneering N/A Sanding Excellent Fastening Screwing Low to moderate Average screw rentention: 308 lb. Nail retention Low to moderate Due to the acidic properties of its extractives this wood tends to accelerate the corrosion of metals, particularly when in contact with unprotected ferrous metal. Hot-dipped galvanized nails are recommended. It is essential that stainless steel, brass, aluminium, copper or metals with a protective coating be used when applying fittings, fixtures or fasteners. Lateral nail holding N/A Gluing Easy Bonds very easily with adhesives of a wide range of properties and under a wide range of bonding conditions. Finishing Staining Easy Very smooth texture achieved, but sometimes difficult to hide natural texture of wood. Very soft wood that loses some grain design as stain becomes darker. Some wild grain was present in Interior red cedar. Painting Moderate to good paint holding ability Lacquering Good Clear coats with little difficulty. A high build clear coat works best for the coastal wood while it was recommended for Interior red cedar to use a clear finish, nitrocellulose/ alkyd sealer and finish system. Performed well in the tape test (i.e., small flakes of the coating were detached along edges and at intersections of cuts) and in the pull-off test (i.e., average strength of 25 kg/cm2). Waxing Good Good results are obtained when using light-, medium- or dark-coloured waxes (e.g., mellow pine, chestnut or jacobean). Drying Ease of drying Moderately easy to difficult The drying of thin boards is generally easy with little degrade to occurring. As red cedar tends to hold its moisture at the centre, care is required when drying thicker stock as internal honey-combing and collapse are common defects. Longer drying times are required. Durability Natural decay resistance Durable Appropriate for outdoor usage. Treatability Impermeable to extremely impermeable Can be improved by incising.
Data for these property tables has been compiled by FPInnovations from internal and external scientific sources.FPInnovations is a not-for-profit technical research institute serving the Canadian forest sector.
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Photo credit: Jonathan Taggart