NOTE: because I have only one hemlock page, my site creation software complains about my having 2 fact sheets, one for Eastern and one for Western, so I've taken the easy way out and just combined the two fact sheets, SO ... directly below is the fact sheet for Eastern hemlock and then down below that is the full fact sheet for Western hemlock.
EASTERN HEMLOCK
BOTANICAL NAME: Tsuga canadensis of the family Pinaceae
The name Tsuga was first applied to the genus in 1847 by the dendrologist Stephen Endlicher and is Japanese meaning yew-leaved. The word canadensis means "of Canada". The genus Tsuga contains about 14 species native to North America and southern and eastern Asia.
COMMON NAMES: abete del canada, american hemlock, black hemlock, canada hemlock, canadese hemlock, canadese hemlock-den, canadian hemlock, common hemlock, eastern hemlock, hemlock, hemlock fir, hemlock pine, hemlock spruce, huron pine, kanadensisk tsuga, new england hemlock, pennsylvania hemlock, perusse, pine, pruche de l'est, pruche prusse, red hemlock, sapin du canada, schierlingstanne, spruce hemlock, spruce pine, spruce, suga, tsuga canadese, tsuga del canada, tsuga du canada, vanlig hemlock, water hemlock, water spruce, west virginia hemlock, white hemlock, wisconsin white hemlock
TYPE: softwood (evergreen)
COLOR: The heartwood is buff to pale brown and the late growth frequently has a reddish or reddish brown tinge. The sapwood is not distinctly separated from the heartwood but may be lighter in color, especially the last few rings out next to the bark.
GRAIN: uneven and frequently twisted (spiral-grained); growth rings are distinct but not conspicuous.
TEXTURE: medium to coarse
PROPERTIES / WORKABILITY: Although it is one of the hardest softwoods, it is only moderately hard in absolute terms and moderately strong. It works reasonably well with hand tools although it is brittle and subject to chipout and splintering. The wood is subject to ring shake. It does not respond very well to machining operations such as planing. Moderately weak in bending, moderately strong in endwise compression, moderately limber, and moderately low in shock resistance.
Pre-drilling recommended to prevent splitting when screwing or nailing, but holds nails satisfactorily if they go in without splitting the wood. Glues easily.
Diifficult to veneer with drying degrade often moderate to severe and with collapse, buckles, and splilts.
DURABILITY: low decay resistance and high resistant to preservative treatment --- should not be used under conditions that promote decay. Susceptible to attack from termites (Isoptera) and Pinworms (ambrosia beetles)
FINISH: Takes paint, stains, varnishes, and polishes well.
STABILITY: no reports found on movement in service
BENDING: poor bending characteristics
ODOR: Although the wood may have a sour odor when freshly cut, it is generally odorless and has no characteristic taste.
TOXICITY: may cause dermatitis
SOURCES: Canada and the United States; Eastern Canad and large swaths of the Eastern US upwards from South Carolina. The tree grows in acid soils in moist cool valleys and rock outcrops, particularly north-facing bluffs. It is often found in pure stands.
USES: agricultural implements, beams, boxes, building construction, building materials, cabin construction, casks, concrete formwork, construction, crates, decks, domestic flooring, doors, factory construction, factory flooring, flooring, form work, foundation posts, framing, heavy construction, joinery, joists, kitchen cabinets, light construction, lumber, millwork, packing cases, pallets, piling, plywood, poles, porch columns, pulpwood, rafters, railroad cars, railroad ties, roof boards, roofing, rough construction, sashes, shakes, sheathing, shingles, siding, sub flooring, sub-flooring, subflooring, toys, vehicle parts
TREE: mature height is typically 60 to 80 feet with trunk diameter of 2 feet to 3 feet but 100 feet with a 4 foot diameter is not terribly rare.
Of relatively slow growth, it reaches maturity in 250 to 300 years, and often lives for 600 years or more.
A record tree was recorded at 160 feet, 7 foot diameter and an age of 988 years.
WEIGHT: 23 to 30 lbs/ft3
DRYING: The timber is reported to shrink to a moderate degree during drying. Shrinkage is:
radial 3%, tangential 7%, volumetric 10%. During drying, Wetwood and compression wood may cause degrades such as uneven moisture content, warp, and ring shakes during drying. There is sometimes severe twisting and warping
AVAILABILITY: readily available
COST:
web quotes:
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It has low fuel value and should not be used in fireplaces or campfires because of its tendency to send sparks for several feet into a room or across the forest floor.
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Hemlock branches were used in steam baths, which were designed to help heal rheumatism, colds, and coughs. These "sweat lodges" also help to induce sweating to break a fever. A tea from the inner bark was made by early settlers to help cure coughs, fevers, and digestive disorders. A wash made from the bark was used externally to help stop bleeding. Alaskan Indians made bread from the inner bark.
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Hemlock is not poisonous. The poison hemlock given to Socrates was brewed from an entirely different plant, a member of the parsley family, Umbelliferae. On the contrary, Indians and woodsmen have brewed teas from the twigs and leaves in the wintertime. The young growth is said to have constituted one of the ingredients of the old-fashioned root beer. The bark is still occasionally used in the Southern Appalachians as a brown dye for wool.
At one time the hemlock was the most abundant tree in the Northeastern forest, according to a report in 1947. But, due to the value of its bark for tanning leather, many of the gigantic trees were felled and stripped of their bark, which was peeled off in rectangular sheets about 4 sq. ft.
For some 200 years the practice used only the bark, leaving downed trees virtually unused and decaying in the forest. Some early lumbermen used the slippery hemlock "peelers" to ease pine logs downriver. Vast "silver forests" composed of downed, weathered hemlocks were common in sections of the East.
Although its bark--rich in tannic acid--was in great demand, for most purposes the wood was inferior to that of the white pine.
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Supplies of hemlock in the United States and Canada are, however, excellent. The wood compares favorably with Lodgepine pine (Pinus contorta) for certain applications, but costs about half the price of lodgepole pine
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This shade and ornamental tree is the state tree of Pennsylvania
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Compared to Western hemlock, Eastern hemlock is reported to be brashy and brittle, and
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WESTERN HEMLOCK
BOTANICAL NAME: Tsuga heterophylla of the family Pinaceae
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".
COMMON NAMES: alaska pine, alpine hemlock, alpine spruce, berg-hemlock, black hemlock, british columbia hemlock, gray fir, grey fir, hemlock, hemlock spruce, huron pine, mountain hemlock, olympic fir, pacific coast hemlock, pacific hemlock, patton's hemlock, patton's spruce, prince albert fir, prince albert spruce, silver fir, tsuga de california, tsuga de californie, tsuga de l'ouest, tsuga de patton, tsuga di california, vastamerikansk berg-hemlock, weeping spruce, west coast hemlock, westamerikanische hemlocktanne, western hemlock, western hemlock fir, western hemlock spruce, white hemlock, williamson's spruce
TYPE: softwood
COLOR: Heartwood is typically cream to pale brown, sometimes darker, and the latewood may be tinged with purplish or reddish-brown color. Sapwood, typically about 2 to 4 inches in width on a mature tree, is only slightly paler than heartwood and can be difficult to distinguish, with no clear demarcation between heart and sap. One report states that sapwood is usually only 1 inch wide, but this is definitely a minority report.
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.
GRAIN: generally straight and even; sometimes exhibits natural growth defects such as latex or other ducts.
TEXTURE: fine to medium
PROPERTIES / WORKABILITY: Moderately light in weight and moderate in strength, hardness, stiffness, and shock resistance but crushing strength is reported as high. Its machining properties are reported to be similar to the pines, and has also been compared to Douglas-fir and Spruce in character.
It responds well to both hand and power tools (slightly better than Eastern hemlock) with little dulling effect on cutters. Mortising, moulding, boring characteristics are good. Planes well and turns well. Sands very well, but surfaces may dent or scratch easily since the wood is soft. It takes stains, polish, varnish and paint well and glues well.
Pre-drilling recommended for screwing and nailing (somewhat prone to splitting although less so than Eastern hemlock, and one report says predilling is not needed). Screwing properties are rated as very good. Both screw-holding and nail-holding qualities are rated as very good.
Moderately easy to veneer but with a slight to moderate potential for buckles and splits
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. Moderately difficult to treat with preservative chemicals.
SHRINKAGE: radial 5%, tangential 8%, Volumetric 13%
FINISH: Takes stains and paint quite well and polishes well. Moderately lusterous.
STABILITY: Reported to have high dimensional stability, when properly dried, even with significant changes in ambient humidity.
BENDING: Bending strength in the air-dry condition is fairly high.
steam bending characteristics are moderate and
ODOR: Wet wood may have a sour odor but there is no distinctive taste.
SOURCES: Western hemlock is reported to occur in Alberta and on the coast of British Columbia in Canada. In the United States it is reported to be 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.
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, doors, exterior trim & siding, exterior uses, factory construction, factory flooring, flooring, form work, foundation posts, framing, fuelwood, furniture, heavy construction, interior construction, joinery, joists, ladders, light construction, oars, packing cases, pallets, 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, veneer, wainscotting
TREE: Largest of the hemlocks, trees reach height of 200 feet, with diameters of 3 feet to 4 feet. Typically has a long slender trunk, often fluted.
WEIGHT: 23 to 37 lbs/ft3
DRYING: Moderately easy to dry, 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. It may contain wetwood and/or have ring shake but is resin-free and odorless when properly dried. Drying defects that may occur in this species include shake, uneven moisture content, chemical stains, warping, and iron stains. Shrinkage is reported to be rather high.
TOXICITY: Some reports of mild skin problems due to the sawdust
AVAILABILITY: readily available
COST: moderate to low
web quotes:
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Apart from timber, the bark of Western hemlock yields large quantities of tannin which is used a mud additive in oil-well drilling.
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Compared to Eastern hemlock, the wood is reported to be finer textured, straight-grained, and lighter in weight.
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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.
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A wood which is quite extensively used for exterior construction. It is a coarse, rough, soft wood with open grain. When well seasoned it is light in weight and in color. It warps badly and splits. A pile of it in the hot sun will literally crawl all over the lot. The western hemlock is better as a rule than the eastern and middle-west product.
This wood is not as easy to paint well as some others. It absorbs the paint unevenly in spots and the paint upon it dries slowly. The paint must be well brushed into the wood to gain good anchorage. Hemlock is not used for interior trim lumber.
Hobbit note: the above quote seems to be in direct contradiction to most reports.