Subalpine fir

Category: Softwood
Region: Interior
Title: Subalpine fir (Abies lasiocarpa)

Subalpine fir, also known as balsam or balsam fir, grows throughout BC’s interior and is marketed with lodgepole pine and interior spruce as the SPF (spruce-pine-fir) species group.

A medium-sized tree that grows about 20 to 35 metres tall and usually found in mid to high elevations, subalpine fir wood is used for lumber, plywood, veneers, boxes and pulp.

Kiln-dried SPF lumber is used as a structural framing material in a wide variety of residential, commercial, industrial and agricultural applications.

Where it grows

Subalpine fir, also known as balsam or balsam fir, grows throughout most of the BC Interior from mid to high elevations, as well as near sea level on the north coast. It is most common in humid, continental boreal climates with a short growing season, grows less frequently in cool temperate climates, and is rare in warmer, drier climates.

It occasionally occurs in pure stands but is usually mixed with other species, principally Engelmann spruce and white spruce. Its high shade tolerance makes it a desirable component in mixed-species stands.

Identifiable characteristics

Subalpine fir is a medium-sized tree that is usually 20 to 35 metres tall and 30 centimetres in diameter, although it can occasionally reach a height of 50 metres. It has a low-taper stem and a narrow, dense, cylindrical crown of short, stiff, drooping branches. The greyish-brown bark breaks into irregular scales with age. They have a lifespan of about 120 to 140 years.

The needles have blunt ends and are often notched at the tip. They are blue-green with a single white band on the top and two beneath. The needles all tend to turn upwards, but a few often stick out from the underside of the branch. Seed cones are deep purple and grow upright at the top of the crown. Like the cones of the other firs, they disintegrate on the tree, leaving a central spike. Pollen cones are bluish.

Common uses and applications

Subalpine fir, lodgepole pine and interior spruce are marketed together as SPF (spruce-pine-fir). Kiln-dried SPF lumber is used as a structural framing material in all types of residential, commercial, industrial and agricultural applications. It is used in the manufacture of prefabricated houses, trusses, and other structural components.

Subalpine fir is also used for plywood veneers, planing-mill products, crates and boxes, sashes, doors, frames, food containers, pulpwood and general millwork. Along with spruce and lodgepole pine, it is used to produce 100 percent bleached Kraft pulp and chemi-thermo-mechanical pulp (CTMP).

Indigenous peoples across North America have long used the pitch and bark of subalpine fir for medicinal purposes, referring to it as “the medicine plant”. Interior Indigenous peoples make large temporary baskets by stitching together sheets of bark with spruce roots. They use boughs for bedding and flooring in sweat lodges. Some also use the wood for roofing shingles and burn rotten wood to make a substance for tanning hides.

Tsleil-Waututh Administration & Health Centre
Photo credit: KK Law

 

Commercial availability

Subalpine fir is produced predominantly as SPF in structural grades according to National Lumber Grades Authority (NLGA) rules for dimension lumber. Select Structural, #2 and better, and stud grades are the most common grades produced. Specialty in-house grades, lamstock and export grades are also available, and appearance grades can be produced according to NLGA rules.

Subalpine fir 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.

 

Download our grading guide

Get acquainted with the most commonly produced and exported lumber grades in boards and structural dimension lumber from BC’s interior softwood species.

Subalpine fir – physical properties

Density (kg/m3)Green331
Air dry351
Specific gravity (12% m.c.)Standard0.33
Hardness (N)Side1557
EndN/A
MOE (Mpa)Green8690
Air dry10300
MOR (Mpa)Green35.6
Air dry55.2
Compression parallel (Mpa)Air dry35.4
Compression perpendicular (Mpa)Air dry3.61
Shear (Mpa)Air dry6.74
Cleavage (N/mm width)Air dryN/A
Shrinkage
OD = oven dry
air = air dry 12%
Radial (OD)2.6%
Tangential (OD)7.4%
Volumetric (OD)9.4%
Volumetric (air)N/A
Tang / rad ratio2.8

Subalpine fir – visual properties

Colour
HeartwoodNearly white to pale reddish-brown.
SapwoodNearly white.
Heartwood / sapwood contrastThe sapwood is not clearly differentiated from the heartwood.
Latewood / earlywood contrastThe annual growth rings often show somewhat prominent brown latewood bands.
Grain
The wood is generally straight-grained with medium to coarse, but even texture.
Figure
Plainsawn lumber or rotary-cut veneer: conspicuous growth ring.
Quartersawn lumber or quarter-sliced veneer: distinct, inconspicuous growth ring stripe.
Knots
Abundant and small.

Subalpine fir – working properties

ProcessPerformanceComments
Machining
PlaningGood planing qualityRecommended planer settings: 20° hook angle and 20 kmpi (knife marks per inch). Due to the usually wide bands of soft earlywood there is a definite tendency for these to become compressed during planing, later lifting to give a ridged surface.
TurningMedium to low surface qualityCommon defects: torn out grain.
SawingEasy to work with toolsDue to the usually wide bands of soft earlywood there is a definite tendency for these to tear in sawing.
BoringMediumMedium boring quality with both brad and single twist bits. Due to the usually wide bands of soft earlywood there is a definite tendency for these to tear in boring operations.
MortisingGood to moderateGood mortising quality when using a hollow chisel mortise. Due to the usually wide bands of soft earlywood there is a definite tendency for these to tear in mortising. Common mortising defects: splintering on the out-going side of the mortise and crushed grain inside the mortise.
ShapingGood shaping qualityCommon shaping defects in the order of frequency: Splintering at the corner, rough end-grain, fuzzy grain, raised grain, and torn grain. Recommended: The use of a counter piece for end-grain shaping.
VeneeringN/A
SandingGood
Fastening
ScrewingModerateAverage screw rentention: 313 lb.
Nail Retention Moderate
Lateral Nail HoldingModerateAbout 40% reduction to Douglas-fir.
GluingEasyBonds very easily with adhesives of a wide range of properties and under a wide range of bonding conditions.
Finishing
StainingEasySmooth finish with little texture. Dark stain produces prominent wild grain. Recommended: light-coloured stains with low penetration power will produce a more even colour.
PaintingAverage to good paint holding ability
LacqueringGoodPerformed well in the tape test (i.e. small flakes of the coating were detached at intersections of cuts) and in the pull-off test (i.e. average strength of 29 kg/cm2).
WaxingGoodBest results are obtained when using light-coloured waxes (e.g. mellow pine).
Drying
Ease of dryingEasy to moderately easyFew defects expected except in the most extreme cases.
Durability
Natural decay resistanceSlightly durableNot appropriate for prolonged outdoor exposure.
TreatabilityImpermeableCan 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.