Western hemlock

Category: Softwood
Region: Coast, Interior
Title: Western hemlock (Tsuga heterophylla)

Western hemlock grows along BC’s coast on both the east and west sides of the Coast Range as well as in the interior wet belt west of the Rocky Mountains. It is a large tree that typically grows 30 to 50 metres and has conspicuously drooping new growth at its top. Western hemlock is used for general construction, roof decking and plywood, as well as for laminating stock and the production of glue-laminated and solid beams. Its strength and stiffness make it a preferred material for use in horizontal components and longer spans.

Western hemlock is the most plentiful tree species on the coast of BC. It is commonly sold and shipped with amabilis fir under the name Hem-Fir, which has an extremely wide range of uses because it offers good strength, appearance and working qualities.

Where it grows

Western hemlock is the single most plentiful tree species on BC’s coast. It grows along both the east and west sides of the Coast Range, from sea level to mid-elevations, as well as in the interior wet belt west of the Rocky Mountains.

Western hemlock seldom grows in pure stands and is instead usually mixed with Douglas-fir, amablis fir, Sitka spruce, and western red cedar. Its shallow root system makes it susceptible to windthrow or wildfire. Occasionally it develops in pure stands after a wind has blown over many trees. Western hemlock tolerates shade and grows abundantly underneath mature trees.

Did you know?

Hemlock was named after a European weed that has a similar smell. Western hemlock is not related to poison-hemlock, the weed that killed Socrates.

Identifiable characteristics

Western hemlock is a large tree that typically grows 30 to 50 metres tall and 1 to 1.5 metres in diameter. It usually lives about 500 years. The tree has a rather narrow crown with conspicuously drooping new growth at the top. It has mostly down-sweeping branches and delicate feathery foliage. The bark is dark brown to reddish-brown, becoming thick and strongly grooved with age.

The needles are nearly flat, glossy and soft. They are yellow to dark green on the upper surface and whitish underneath. They are unequal in length and produce feathery flat sprays. The small, numerous seed cones are greenish to reddish-purple and turn brown with age.

Common uses and applications

Western hemlock and amabilis fir are nearly identical in appearance and physical properties so they are commonly sold and shipped together under the name Hem-Fir. Trees of both species are shade-tolerant and prune themselves as they grow to produce a tall, branch-free trunk. In dense stands they may have a clear stem for three-quarters of their height, a natural growth characteristic that produces large amounts of Clear and Factory lumber from the log.

Western hemlock is used for general construction, roof decking and plywood, as well as for laminating stock and the production of glue-laminated and solid beams. Compared to other species, its strength and stiffness make it a preferred material for use in horizontal components and longer spans. Hemlock timbers are often treated for railway ties.

Western hemlock’s excellent working properties make it the first choice for mouldings and interior woodworking. It is widely used in joints, veneered interior panelling, furniture, doors, floors and windows, and is also used for pulp and newsprint.

Indigenous peoples carve hemlock to make spoons, combs, roasting spits and other implements. Hemlock roots are sometimes spliced into bull kelp dishing lines to strengthen them. Hemlock bark is rich in tannin and is used as a stain to treat wood and a dye to colour wool and other textiles.

Commercial properties

Western hemlock has a relatively good strength-to-weight ratio and is known for its working properties. The wood requires special care when drying but yields a quality product. Its even density provides for excellent machining properties. It turns, planes and shapes well and can be sanded to a smooth finish.

It is non-resinous and takes any stains or finishes extremely well. It sands smoothly, glues easily and has a high nail and screw holding ability.

Commercial availability

Western hemlock is commonly sold and shipped together with amabilis fir under the commercial designation Hem-Fir (also often referred to as Hem-Bal). Hem-Fir is primarily available as structural lumber for North America, Japan and other export markets.

In North America, structural grades are in accordance with the National Lumber Grades Authority (NLGA) rules for dimension lumber. Select Structural, #2 and better, and stud grades are the most common grades produced for North America, with squares being the most common Japanese product. Specialty in-house grades, lamstock and export grades such as E-120 for Japan are also marketed.

Appearance grades are produced according to NLGA rules. The most common are clears, shop lumber and moulding stock, although many potential appearance grades can be produced.

Western hemlock 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.