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Picea sitchensis |
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Family: Pinaceae |
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Sitka Spruce |
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The genus Picea
is composed of about 30 species native to North America [12] and Eurasia [20].
The word picea
comes from the ancient Latin name (pix, picis = pitch) of a pitchy
pine, probably Scotch pine (Pinus sylvestris L.). The word sitchensis is for Sitka Island
(now Baranof Island) in southeastern Alaska.
Other Common
Names:
Abete di Sitka, British Columbia sitka-spruce, coast west spruce, coast spruce,
eipcea de menzies, epicea de Menzies, epicea de Sitka, epinette de sitka, great
tideland spruce, menzies spar, Menzies spruce, menziesie, picea de Sitka, picea
di Sitka, sequoia silver spruce, silver spruce, Sitka spar, Sitka spruce,
sitka-fichte, sitkafichte, Sitka-gran, sitka-gran, sitkankuusi, sitka-spar,
spruces d'america, tideland spruce, West Coast spruce, western spruce, yellow
spruce.
Distribution: Sitka spruce is native
to the Pacific Coast region from southern Alaska (Kodiak Island and Cook Inlet)
, southeast through southeastern Alaska, western British Columbia, western
Washington, western Oregon and northwestern California.
The Tree: Sitka spruce trees
normally reach heights of 160 feet, with diameters of 5 feet. A record tree was
recorded to be 216 feet tall, with a diameter of 16.7 feet.
General Wood
Characteristics:
The sapwood of Sitka spruce is a creamy white to light yellow, while the
heartwood is pinkish yellow to brown. It may be 3 to 6 inches wide or even
wider in young trees. The wood has a fine, uniform texture and generally has a
straight grain. It is moderately light in weight, moderately low in bending and
compressive strength, moderately stiff, moderately soft, and moderately low in
resistance to shock. On the basis of weight, it rates high in strength
properties and can be obtained in clear, straight-grained pieces. It has moderately
small shrinkage. It is not difficult to kiln-dry and can be worked easily (when
free of knots). It has a low resistance to decay and is resistant to
preservation treatments under pressure, but can be treated by a water diffusion
process. Thin panels of Stika spruce are highly resonant, making them desirable
for piano sounding boards.
Mechanical
Properties (2-inch standard)
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Compression |
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Specific gravity |
MOE x106 lbf/in2 |
MOR lbf/in2 |
Parallel lbf/in2 |
Perpendicular lbf/in2 |
WMLa in-lbf/in3 |
Hardness lbf |
Shear lbf/in2 |
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Green |
0.37 |
1.23 |
5700 |
2670 |
280 |
6.3 |
350 |
760 |
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Dry |
0.42 |
1.57 |
10200 |
5610 |
580 |
9.4 |
510 |
1150 |
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aWML = Work to maximum load.
Reference (56). |
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Drying and
Shrinkage
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Type of shrinkage |
Percentage of
shrinkage |
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0% MC |
6% MC |
20% MC |
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Tangential |
7.5 |
6.0 |
3.8 |
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Radial |
4.3 |
3.4 |
1.4 |
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Volumetric |
11.5 |
9.2 |
2.5 |
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References: (185, 56,
192). |
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Kiln Drying
Schedulesa
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Conventional
temperature/moisture content-controlled schedulesa |
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4/4,
5/4 |
6/4
stock |
8/4 |
10/4 |
12/4 |
British
schedule |
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Lower grades |
T7-A5 |
NA |
NA |
NA |
NA |
NA |
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Upper grades |
T12-B5 |
T12-B4 |
T11-B3 |
T5-B2 |
T5-B2 |
J |
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aReference
(28, 185). |
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Conventional
temperature/time-controlled schedulesa |
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Lower
grades |
Upper
grades |
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4/4,
5/4 stock |
6/4
stock |
8/4
stock |
4/4,
5/4 stock |
6/4
stock |
8/4
stock |
12/4,
16/4 stock |
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Standard |
294 |
294 |
287 |
287 |
287 |
290 |
288 |
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aReferences
(28, 185). |
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Working
Properties:
Sitka spruce is easily worked if free of knots.
Durability: Sitka spruce is rated
as slightly or nonresistant to heartwood decay (14).
Preservation: It is resistant to
preservation treatments under pressure, but can be treated by a water diffusion
process.
Uses: Lumber, pulpwood,
sounding boards for high quality pianos, guitar faces, ladders, components for
experimental light aircraft, oars, planking, masts and spars for boats, and
turbine blades.
Toxicity: Working with fresh wood
may cause dermatitis or other contact sensitivities (8,11&16).
Additional
Reading and References Cited (in parentheses)
1. Betts, H. S.
Sitka Spruce (Picea
sitchensis).
Washington, DC, USA: USDA Forest Service.
2. Boone, R. S.;
Kozlik, C. J.; Bois, P. J., and Wengert, E. M. Dry kiln schedules for
commercial woods - temperate and tropical. Madison, WI: USDA Forest Service,
FPL-GTR-57; 1988.
3. Cary, N. L.
Sitka Spruce, its uses, growth, and management. Washington, DC, USA: USDA
Forest Service, Bulletin No. 1060.; 1922.
4. Dallimore,
W.; Jackson, A. B., and Harrison, S. G. A handbook of Coniferae and
Ginkgoaceae. London, UK: Edward Arnold Ltd.; 1966.
5. Elias, T. S.
The complete trees of North America, field guide and natural history. New York,
NY: van Nostrand Reinhold Co.; 1980.
6. Harris, A. S.
Picea
sitchensis
(Bong.) Carr. Sitka spruce. in: Burns, R. M. and Honkala, B. H., tech. coords.
Silvics of North America. Volume 1, Conifers. Washington, DC: USDA Forest
Service; 1990; pp. 260-267.
7. Harris, A. S.
Sitka Spruce, an American wood. Washington, DC, USA: USDA Forest Service,
FS-265; 1984.
8. Hausen, B. M.
Woods injurious to human health. A manual. New York, NY: Walter de Gruyter;
1981.
9. Henderson, F.
Y. A handbook of softwoods. London: HMSO; 1977.
10. Little, jr.
E. L. Checklist of United States trees (native and naturalized). Washington,
DC: USGPO, USDA Forest Service, Ag. Handbook No. 541; 1979.
11. Mitchell, J.
and Rook, A. Botanical dermatology: plants and plant products injurious to the
skin. Vancouver, BC: Greenglass Ltd.; 1979.
12. Simpson, W.
T. Dry kiln operator's manual. Madison, WI: USDA Forest Service, FPL Ag.
Handbook No. 188; 1991.
13. Summitt, R.
and Sliker, A. CRC handbook of materials science. Vol. 4. Boca Raton, FL: CRC
Press, Inc.; 1980.
14. USDA. Wood
handbook: wood as an engineering material. Madison, WI: USDA Forest Service,
FPL Ag. Handbook No. 72; 1974.
15. Welo, L. A.
Emergency seasoning of Sitka Spruce. Scientific American Supplement.
1919(2269):404-405.
16. Woods, B.
and Calnan, C. D. Toxic woods. British Journal of Dermatology. 1976; 95(13):1-97.