Tsuga Heterophylla (Western hemlock)

Scientific Name
Tsuga heterophylla

Trade Name
Western hemlock

Family Name
Pinaceae

Common Names
Alaska pine, British Columbia hemlock, British columbian hemlock, Gray fir, Grey fir, Hemlock spruce, Huron pine, Pacific Coast hemlock, Pacific hemlock, Prince Albert fir, Prince Albert spruce, Silver fir, West coast hemlock, Western hemlock, Western hemlock fir, Western hemlock spruce, White hemlock

Regions of Distribution
North America

Countries of Distribution  [VIEW MAP]
Canada, United States

Common Uses
Beams, Boat building: masts, Boxes and crates, Broom handles, Building construction, Building materials, Cabin construction, Cabinetmaking, Canoes, Casks, Ceiling, Concrete formwork, Construction, Cooperages, Decks, Decorative plywood, Domestic flooring, Exterior trim & siding, Exterior uses, Factory construction, Factory flooring, Flooring, Form work, Foundation posts, Framing, Fuelwood, Furniture, Heavy construction, Interior construction, Joinery, Joists, Light construction, Oars, Packing cases, Paneling , Paneling, Parquet flooring, Piling, Plywood, Porch columns, Pulp/Paper products, Pulpwood, Railroad cars, Railroad ties, Rough construction, Shingles, Siding, Structural plywood, Sub-flooring, Utility plywood, Vehicle parts, Wainscotting

Environmental Profile

Distribution Overview
Western hemlock occurs in Alberta and on the coast of British Columbia in Canada. In the United States it is distributed in Alaska, California, Idaho, Montana, Oregon, Washington. It usually occurs in dense pure stands with Sitka spruce and other conifers. It thrives well in moist, acid soils, especially flats and lower slopes. Hemlock is also reported to grow in the forests of Japan, China, and India.

Heartwood Color

The latewood region is often tinged with a roseate, purplish, or reddish-brown color. Dark streaks (bird pecks) caused by maggots of a small black fly (chilosia alaskensis) are often present, and are often used to identify the wood. Western hemlock and Amabilis fir (Abies amabilis ) are very similar in appearance and are difficult to separate by inspection

Sapwood Color

The sapwood is about 3 to 5 inches (7 to 13 cm) in width, and is difficult to differentiate from the heartwood.

Grain

Texture

Transition from early wood to latewood is subtle.

Luster

Natural Growth Defects

Natural Durability

The timber has very little natural resistance to decay, and should not be used under high decay hazard conditions unless it is properly and adequately protected.

Odor

Toxicity

Kiln Schedules

Drying Defects

Drying defects that may occur in this species include shake, uneven moisture content, chemical stains, warping, and iron stains.

Ease of Drying

The wood dries slowly because of its high moisture content but it seasons well, and can be air-seasoned or kiln-dried to minimize degrade. The material is resin-free and odorless when properly dried.

Tree Identification

Tree Size

Although Western hemlock is the state tree of Washington, it is reported to grow more extensively in Alaska. It is the largest of the hemlocks, and produces a long, slender, and often fluted trunk

Product Sources
Hemlock is abundant in supply in the United States and Canada. It is also widely used in Japan. One of the most valuable sources of timber in Canada, Western hemlock is exported around the world.

Apart from timber, the bark of Western hemlock yields large quantities of tannin which is used a mud additive in oil-well drilling.

Comments
General finishing qualities are rated as satisfactory

Blunting Effect

The wood works with little dulling effect on cutters

Boring

Cutting Resistance

Gluing

Mortising

Moulding

Movement in Service

It is highly rated for its stability under different moisture content conditions

Nailing

Planing

Resistance to Impregnation

Resistance to Splitting

Response to Hand Tools

Sanding

Screwing

Turning

Veneering Qualities

Steam Bending

Painting

Polishing

Staining

Properly dried wood is easy to stain.

Varnishing

Strength Properties

One of the most common trees in the Pacific Northwest, Western hemlock is reported to form wide, thick groves. Its timber is a primary source of pulwood, and also yields cellulose which is used for making cellophane, rayon, yarns, and plastics. Compared to Eastern hemlock, the wood is finer textured, straight-grained, and lighter in weight. Its machining properties are similar to the pines, and has also been compared to Douglas-fir and Spruce in character

Numerical Data

References
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Betts, H.S.,1945,American Woods – Western Hemlock,USDA, Forest Service American Woods

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