Red alder

Category: Hardwood
Region: Coast
Title: Red alder (Alnus rubra)

Red alder is the most plentiful hardwood on BC’s coast. The medium-sized broadleaf tree grows up to 24 metres and has a life span of 40 to 60 years. Its wood is moderately dense and uniformed textured, and it is an important species for many specialty products.

Red alder is increasing in popularity for use in furniture, flooring, cabinets, turnery, decorative veneer and other home décor products. It is also used for high-value products such as doors and shutters, domestic woodenware and toys.

Where it grows

Red alder is found all along the coast of BC and is the most plentiful hardwood in the region. It does not tolerate shade well and occupies a site quickly after a disturbance. It grows rapidly in even-aged pure stands, often shading out conifers such as Douglas-fir. It is found on sites rich with nutrients, including floodplains and streambanks.

Red alder occurs with all of the low-elevation coastal tree species, including black cottonwood, grand fir, Douglas-fir and the cedars. It tends to be associated with a dense layer of shrubs and herbs such as salmonberry, red elderberry and several ferns.

Identifiable characteristics

Red alder is a medium-sized broadleaf tree that grows up to 24 metres. In the forest, it develops a slightly tapered trunk extending up to a narrow, rounded crown. In the open, its crown starts near the ground, giving it a broad cone shape.
The oval-shaped leaves have pointed tips and coarsely toothed edges that tend to curl under. Hair-covered veins form a ladder-like pattern on the leaf. The leaves are bright green on top and greenish underneath and stay green under they drop off. The bark is thin and is greenish on young trees and turns grey to whitish with age. The inner bark and fresh wounds tend to turn deep reddish-orange when exposed to air. Red alder matures at about 60 years, and rarely lives past 100 years.

Did you know?

Red alder wood is low in pitch so it is good for smoking meat and seafood. Its smoke is delicate, subtle and slightly sweet.

Common uses and applications

Red alder has been increasing in popularity, and is used for furniture, flooring, cabinets, turnery, decorative veneer and other home decorations, as well as craft products such as domestic woodenware and toys. Additional high-value products made with red alder include doors, shutters, mouldings, panel stock and carvings. Lower-grade wood is used in plywood core stock, chips for pulp and paper, as well as firewood, charcoal, and chips for smoke curing.

Indigenous peoples use the bark of red alder as a dye for basket materials, wood, wool, feathers, human hair and skin. Depending on the techniques used, colours range from black to brown to orange-red. The tree’s inner cambium layer is used for food by some coastal groups. It is also used to smoke meats and carve items such as bowls.

 

Commercial properties

Red alder is light in weight with medium strength and hardness, and it is well known for its working properties. The wood dries well although care must be taken to control the colour. It is relatively easy to work, with good machining qualities. It turns, planes and shapes well and can be sanded to a smooth finish. The wood glues easily, has moderate nail and screw holding ability, and takes a good finish.

Did you know?

Red alder is often used for guitars because it has many sonic advantages—it is a lightweight, closed-pore wood that has a resonant, balanced tone. Fender adopted alder for electric instrument bodies in mid-1956, and still uses it today.

 

Commercial availability

Red alder is the most available of BC hardwoods. Appearance and millworking grades are produced according to National Hardwood Lumber Association (NHLA) rules. Common grades include Select and better, #1 shop, and framegrade. A number of proprietary grades also exist.

Red alder lumber is dried according to end-use and customer specifications. Kiln drying inhibits natural staining of the wood, enhances its appearance, and increases its resistance to decay and attack by insects.

Red alder – physical properties

Density (kg/m3)Green373
Air dry390
Specific gravity (12% m.c.)Standard0.37
Hardness (N)Side2490
End4360
MOE (Mpa)Green8270
Air dry10100
MOR (Mpa)Green43.4
Air dry73.8
Compression parallel (Mpa)Air dry40
Compression perpendicular (Mpa)Air dry4.00
Shear (Mpa)Air dry7.96
Cleavage (N/mm width)Air dry53.4
Shrinkage
OD = oven dry
air = air dry 12%
Radial (OD)4.2%
Tangential (OD)7.0%
Volumetric (OD)11.7%
Volumetric (air)8.0%
Tang / rad ratio1.7

Red alder – visual properties

Colour
HeartwoodPale pinkish-brown.
SapwoodSimilar to heartwood.
Heartwood / sapwood contrastNo visible boundary between heartwood and sapwood.
Latewood / earlywood contrastThe annual growth rings are indistinct as it is a diffuse-porous wood.
Grain
The wood has fairly straight grain, and is fine-grained and even-textured.
Figure
Plainsawn lumber or rotary-cut veneer: faint growth ring.
Quartersawn lumber or quarter-sliced veneer: scattered large flakes from compound rays (sometimes entirely absent).
Knots
Few live knots in stem.

Red alder – working properties

ProcessPerformanceComments
Machining
PlaningExcellent palnning qualityRecommended planer settings: 20° hook angle and 12, 16 or 20 kmpi (knife marks per inch). No major defects.
TurningMedium to good surface quality
SawingEasy to work with tools
BoringMediumMedium to good boring quality with brad point bits and lower quality with single twist bits.
MortisingGood to moderate Good mortising quality when using a hollow chisel mortise.
ShapingGood shaping qualityRecommended: The use of a counter piece for end-grain shaping.
VeneeringN/A
SandingGoodExcellent sanding quality.
Fastening
ScrewingGood to moderateAverage screw rentention: 518 lb.
Nail retention Good
Lateral nail holdingN/A
GluingEasyBonds very easily with adhesives of a wide range of properties and under a wide range of bonding conditions.
Finishing
StainingEasy to moderately easyAttractive natural colour. Light stain works well. Blotchy when dark stain used. Smooth finish achieved.
PaintingAverage to good paint holding ability
LacqueringGoodPerformed well in the tape test (i.e. edges of the cuts were completely smooth; none of the squares of the lattice was detached) and in the pull-off test (i.e. average strength of 29 kg/cm2).
WaxingGoodExcellent results are obtained when using light- to dark- coloured waxes (e.g. mellow pine, chestnut, and jacobean).
Drying
Ease of dryingModerateThe colour of the wood is affected by the temperature and humidity of the schedule.
Durability
Natural decay resistanceNon-durableLogs should be processed quickly, particularly during warm weather, as decay proceeds rapidly. Green lumber should be carefully stacked for air-drying or promptly kiln dried to prevent damage from microbial stain.
TreatabilityN/A