Trembling aspen

Category: Hardwood
Region: Interior
Title: Trembling aspen (Populus tremuloides)

Photo credit: Barbara Zimonick

Trembling aspen is a slender, graceful tree with smooth, greenish white bark and distinctive leaves that quiver in the slightest breeze, giving it its name.

Trembling aspen is the most common of the fast-growing, small-diameter species used to make oriented strand board (OSB) and laminated veneer lumber (LVL). Aspen has gained acceptance in the construction market as studs, and its bright white colour is well suited to appearance applications.

It is found throughout British Columbia (B.C.) east of the Coast Range.

Where it grows

Trembling aspen grows in many soil conditions across the B.C. interior from sea level to 3,000 metres and is especially common in the northeast. It often appears in even-aged, pure stands and has a shorter lifespan than most trees due to its susceptibility to decay. Aspen sprout from root suckers and form clones of individual stems. Many kinds of wildlife use the foliage, twigs and buds for food.

Did you know?

OSB is a widely used, economical structural wood panel that uses fast-growing species like aspen to make efficient use of forest resources. The panels are made from thin strands of wood sliced from small-diameter roundwood logs or blocks and bonded together with a waterproof phenolic adhesive that is cured under heat and pressure.

Trembling aspen species distribution map

Identifiable characteristics

Trembling aspen is a deciduous broadleaf tree with smooth greenish-white bark that does not peel. A fast-growing tree, it lives on average 50 to 75 years and rarely more than 150 years. It grows up to 40 metres tall and has distinctive leaves that quiver in the slightest breeze. The leaves are smooth and round to triangular shaped with a flattened stalk that is longer than the leaf. The leaves are dark green on top and paler underneath and turn golden yellow or red in the fall. Male and female flowers grow on separate trees—male catkins are two to three centimetres and female catkins are four to 10 centimetres. The fruit are tiny capsules covered with cottony down.

Daytime winter stark image of Trembling Aspen (Populus tremuloides) stand, showing white and black bark

Common uses and applications

Aspen is the most common species used for oriented strand board (OSB) and can be used to produce high-quality laminated veneer lumber (LVL) for headers, joists, beams and planks. It can be sawn into studs for construction lumber under National Lumber Grades Authority rules, and there is interest in producing it for millwork.

Indigenous peoples have many uses for aspen, including medicine, food and a source of poles, canoe paddles and bowls. Aspen bark contains salicylates, the original basis for aspirin. Lye made from aspen ashes and animal fat is turned into soap and used to prepare moose hides.

Trembling aspen is often grouped with black cottonwood (Populus balsamifera ssp. trichocarpa) and balsam poplar (Populus balsamifera ssp. balsamifera)—two varieties of the same species. Balsam poplar is used for pulp and construction, and black cottonwood is used to make tissues and other paper products.

Photo credit: Brudder Productions

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Commercial properties

Trembling aspen wood is light and soft, with a straight, fine, even-textured grain. It can be used for appearance applications due to its bright white colour. It has good planing and turning performance, good screw retention, and resistance to splitting. It is moderately easy to glue and finishes well.

Photo credit: Moresby Creative

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Commercial availability

Appearance and millworking grades can be produced according to National Hardwood Lumber Association rules. The 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 insect attacks.

Photo credit: Michael Bednar

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Trembling aspen – physical properties

Density (kg/m3)Green374
Air dry408
Specific gravity (12% m.c.)Standard0.37
Hardness (N)Side2140
MOE (Mpa)Green9030
Air dry11200
MOR (Mpa)Green37.6
Air dry67.6
Compression parallel (Mpa)Air dry36.3
Compression perpendicular (Mpa)Air dry3.52
Shear (Mpa)Air dry6.76
Cleavage (N/mm width)Air dry45.5
OD = oven dry
air = air dry 12%
Radial (OD)3.6%
Tangential (OD)6.6%
Volumetric (OD)11.8%
Volumetric (air)8.3%
Tang / rad ratio1.8

Trembling aspen – visual properties

HeartwoodVaries from off-white to creamy to light greyish-brown.
SapwoodNearly white.
Heartwood / sapwood contrastThere is no distinct colour boundary between sapwood and heartwood to clearly delineate one from the other.
Latewood / earlywood contrastThe diffuse porous nature of this species makes growth ring recognition difficult.
Straight-grained, fine and even-textured.
Plainsawn lumber or rotary-cut veneer: faint growth rings.
Quartersawn lumber or quarter-sliced veneer: none.
Discolouration above and below knots form and a “comet-tail” or “keyhole”
It has a characteristic disagreeable odour when wet, but is odourless when dry. Wood is soft and light. It weathers to a light grey with a pronounced silky lustre.

Trembling aspen – working properties

PlaningGood planing qualityRecommended planer settings: 12° or 20° hook angle and 16 or 20 kmpi (knife marks per inch).
TurningGood surface qualityCommon defects: torn out grain and, less severe, fuzzy grain. Sanding usually eliminate these defects.
SawingResistance to sawing varies widelyModerately good when compared to other lower-density wood species but poor when compared to higher-density hardwoods (e.g. maple).
BoringModerate qualityRecommended settings: use brad point bit.
MortisingVery goodVery good mortising quality when using a hollow chisel mortise.
ShapingVery good
SandingGoodHeavily affected by fuzzy grain. Recommended settings: finer sandpaper after the initial sanding to eliminate fuzzy grain and the sandpaper frequently changed.
ScrewingGoodGood holding. Good resistance to splitting. Average screw retention: 482 lb.
NailingSatisfactoryGood resistance to splitting.
GluingModerately easyGood adhesion.
StainingGoodFinishes well. Blotches appear as the stains become darker. Recommended: light to medium stains.
LacqueringGoodPerformed well in the tape test.
WaxingSatisfactoryBest when using light-coloured waxes (e.g. mellow pine).
Heartwood durability
Natural decay resistanceLowLow decay resistance limits age of trees.
TreatabilityVery goodVery permeable wood.

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.