Early uses of hemlock in Alaska were limited to mine timbers,
rough-sawn lumber, house logs, poles and pilings, railroad
and mine ties and fuel wood. Since the 1950s, hemlock fibers
have been use in the production of specialty dissolving pulp
in Southeast Alaska and are among the finest of raw material
for this use. Western hemlock is relatively hard and is among
the stronger western softwoods. Uses today include framing,
architectural members, trim, roof decking, laminating stock,
moldings, structural lumber, and veneer for plywood. In comparison
with other commonly known construction species, such as Douglas
fir, the wood of western hemlock is moderately light in weight,
moderately low in shock resistance, and has moderately large
shrinkage. Western hemlock is almost tasteless and odorless
when seasoned, making it especially well-suited for food containers.
Western hemlock lumber gives good service in construction,
although it has little resistance to decay.
Western hemlock is somewhat resistant to conventional preservative
treatment. It can be pressure treated but is more effectively
treated by a water diffusion process.
Western hemlock is the most abundant tree species grown
in Southeast Alaska. It is native to the Pacific coast
region from southern Alaska (Kenai Peninsula) southeast
through southeastern Alaska and western British Columbia
to western Washington, western Oregon and northwestern
California. The species is also found in the Rocky Mountain
region from southeastern British Columbia south to northeastern
Washington, northern Idaho and northwestern Montana.
Tree. Western hemlock trees reach heights of
200 feet, with diameters of 3 feet. An exceptional specimen
was recorded at 259 feet tall, with a diameter of 108
The genus Tsuga contains
about 14 species native to North America  and southern
and eastern Asia . The word tsuga is the
Japanese name for the native hemlocks of Japan. The
word heterophylla means "with other (different
or various) leaves."
Wood Characteristics. The heartwood and sapwood of
western hemlock are brown with a purplish tinge. Both are
light reddish and nearly indistinguishable from each other.
The sapwood, which is sometimes lighter in color, is generally
not more than 1 inch thick. The wood often contains small,
sound, black knots that are usually tight and stay in place.
Dark streaks are often found in the lumber; these are caused
by hemlock bark maggots and generally do not reduce strength.
The wood is moderate in its hardness, stiffness, and shock
resistance and has moderately large shrinkage (about the same
as Douglas-fir). Green hemlock lumber contains considerably
more water than Douglas-fir and requires a longer kiln drying
time. Trees may contain wet wood and/or have ring shake.
Properties. The wood has a fine, moderately even
texture, is nonresinous, and is easily machined and worked.
The wood is intermediate in nail holding ability and has a
tendency to split when nailed. It is satisfactory with respect
to being glued and in taking stains, polish, varnish and paint.
The wood is easy to work in all hand and machine operations
and has little dulling effect on cutting edges. A clean finish
can generally be obtained if sharp tools are used and are
honed free from wire edges. However, the wood must be supported
at the tool exit to prevent chipping out. The wood has a tendency
to chip bruising in planing which can be overcome by having
an efficient cleanout system which keeps debris from building
up in front of the cutter heads. The wood is readily sliced
to a smooth silky finish which is advantageous for the manufacture
of veneers and plywood. It has good density and fiber length
which makes it the most desirable species for making quality
pulp and paper.