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Sequoia sempervirens |
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Family: Taxodiaceae |
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Redwood |
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The genus
Sequoia is represented by one species (S. sempervirens). A related tree, the
giant sequoia (Sequoiadenrdon giganteum) is also called redwood, big tree or
giant redwood. The word sequoia was selected to honor Sequoyah (also spelled
Sequoia), or George Guess (1770?-1843), Native American inventor of the Cherokee
alphabet. The name was unexplained by its author, an Austrian linguist and
botanist. The name sempervirens means evergreen.
Other Common
Names:
Amerikansk sekvoja, California cedar, California redwood, Californische
redwood, coast redwood, corla, giant-of-the-forest, Humboldt redwood, ledwood,
Mexican cherry, palo colorado, pin rouge d'ambrique, pin rouge d'Amerique, pino
rosso d'america, redwood, sequoia, sequoia de California, sequoia roja, sequoia
rossa, sequoia toujours vert, sequoie, vavona, vavona burr.
Distribution: Redwood is native to
the Pacific Coast region from extreme southwestern Oregon (Curry County) south
to central California (Monterey County).
The Tree: Redwood trees reach
heights of 200 to 300 feet, with diameters of 6 to 12 feet. The record is 376
feet tall, with a 20 foot diameter and an age of 2,200 years, and represents
the world’s tallest tree.
General Wood
Characteristics:
The sapwood of is white, while the heartwood is a dark reddish brown. The
heartwood has no characteristic odor or taste. It has exceptionally straight
grain, high dimensional stability and is resistant to warping. It is moderately
strong in bending, strong in endwise compression, stiff, moderately low in
shock resistance and holds paint well.
Weight
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Weight |
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Moisture content |
Specific gravity |
lb/ft3 |
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Old Growth |
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Green |
0.38a |
50b |
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12% |
0.40a |
28b |
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Ovendry |
0.42b |
NA |
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Second Growth |
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Green |
0.34a |
42c |
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12% |
0.35a |
24c |
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Ovendry |
0.36c |
NA |
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??aReference
(15).
??bReference
(14).
??cReference
(9).
Mechanical
Propertiesa?
|
Property |
Green |
Dry |
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Old Growth |
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MOE |
1.18
¥ 106 lbf/in2 |
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1.34
¥ 106 lbf/in2 |
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MOR |
7.50
¥ 103 lbf/in2 |
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10.00
¥ 103 lbf/in2 |
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C| | |
4.20
¥ 103 lbf/in2 |
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6.15
¥ 103 lbf/in2 |
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C^ |
0.42
¥ 103 lbf/in2 |
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0.70
¥ 103 lbf/in2 |
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WML |
7.4
in-lbf/in3 |
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6.9
in-lbf/in3 |
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Hardness |
410
lbf |
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480
lbf |
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Shear| | |
0.80
¥ 103 lbf/in2 |
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0.94
¥ 103 lbf/in2 |
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Second Growth |
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MOE |
0.96
¥ 106 lbf/in2 |
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1.10
¥ 106 lbf/in2 |
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MOR |
5.90
¥ 103 lbf/in2 |
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7.90
¥ 103 lbf/in2 |
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C| | |
3.11
¥ 103 lbf/in2 |
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5.22
¥ 103 lbf/in2 |
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C^ |
0.27
¥ 103 lbf/in2 |
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0.52
¥ 103 lbf/in2 |
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WML |
5.7
in-lbf/in3 |
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5.2
in-lbf/in3 |
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Hardness |
350
lbf |
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420
lbf |
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Shear| | |
0.89
¥ 103 lbf/in2 |
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1.11
¥ 103 lbf/in2 |
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Drying and
shrinkage
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Percentage
of shrinkage (green to final moisture content) |
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Type of shrinkage |
0%MCa |
6%MCb |
20%MCb |
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Old Growth |
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Tangential |
4.4 |
3.5 |
1.5 |
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Radial |
2.6 |
2.1 |
0.9 |
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Volumetric |
6.8 |
5.4 |
2.3 |
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Second Growth |
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Tangential |
4.9 |
NA |
NA |
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Radial |
2.2 |
NA |
NA |
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Volumetric |
7.0 |
NA |
NA |
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??aReference
(15).?
??bReference
(14).
Kiln Drying
Schedulesa
Conventional
Temperatures/Moisture Content-Controlled Schedulesa
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Condition |
4/4,
5/4 stock |
6/4
stock |
8/4 stock |
10/4 stock |
12/4 stock |
British
Schedule 4/4 stock |
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Light |
T5-D6 |
NA |
T5-D4 |
T5-C4 |
T5-C3 |
K |
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Heavy |
T4-F5 |
T3-F5 |
T3-F4 |
NA |
NA |
NA |
?aReference
(2&13).
?Conventional
Temperatures/Time-Controlled Schedulesa
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? |
Lower
Grades |
Upper
grades |
|||||
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Condition |
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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Light |
289 |
288 |
b |
289 |
288 |
b |
NA |
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Medium & Heavy |
c |
c |
c |
c |
c |
c |
NA |
?aReferences
(2&13).
?bAir dry to 20%
MC, then dry using table 286 (13).
?c Air dry to
20% MC, then dry using table 289. Prone to collapse(13).
Working
Properties:
Redwood works easily with both hand and machine tools, with little dulling
effect on tools. It planes well, provided the cutters are sharp and it
splinters easily when working on the end grain. It holds nails well, and paints
and finishes satisfactorily. It also stains well, but glues best with alkaline
adhesives.
Durability: Redwood is rated as
resistant to very resistant to heartwood decay.
Preservation: Redwood is moderately
resistant to preservative treatments.
Uses: High value building
construction, heavy beams, bridge timbers, planks, siding, sash, doors, veneer,
furniture, cooling equipment, plywood, pulping, particle board, shakes,
shingles, grape stakes, posts and novelties (from burl wood).
Toxicity: Working with redwood
may cause allergic reactions (4,10&16).
Additional
Reading and References Cited (in parentheses)
1. Betts, H. S.
Redwood (Sequoia
sempervirens).
Washington, DC, USA.: USDA Forest Service, USGPO, O-940471; 1945.
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. Dallimore,
W.; Jackson, A. B., and Harrison, S. G. A handbook of Coniferae and
Ginkgoaceae. London, UK: Edward Arnold Ltd.; 1966.
4. Hausen, B. M.
Woods injurious to human health. A manual. New York, NY: Walter de Gruyter;
1981.
5. Henderson, F.
Y. A handbook of softwoods. London: HMSO; 1977.
6. Lindquist, J.
L. Redwood, an American wood. Washington, DC, USA.: USDA Forest Service,
FS-262.; 1974.
7. Little, jr.
E. L. Checklist of United States trees (native and naturalized). Washington,
DC: USGPO, USDA Forest Service, Ag. Handbook No. 541; 1979.
8. Luxford, R.
F. and Markwardt, L. J. The strength and related properties of redwood.
Washington, DC, USA.: USDA Forest Service, Technical Bulletin No. 305; 1932.
9. Markwardt, L.
J. and Wilson, T. R. C. Strength and related properties of woods grown in the
United States. Washington, DC: USGPO, USDA Forest Service, Tech. Bull. No. 479;
1935.
10. Mitchell, J.
and Rook, A. Botanical dermatology: plants and plant products injurious to the
skin. Vancouver, BC: Greenglass Ltd.; 1979.
11. Olson, Jr.
D. F.; Roy, D. F., and Walters, G. A. Sequoia sempervirens (D. Don) Endl. in: Burns,
R. M. and Honkala, B. H., tech. coords. Silvics of North America. Volume 1,
Conifers. Washington, DC: USDA Forest Service; 1990; pp. 541-551.
12. Show, S. B.
and Stuart, R. Y. Timber growing and logging practice in the coast redwood
region of California. Washington, DC, USA: USDA Forest Service, Technical
Bulletin No. 283; 1932.
13. Simpson, W.
T. Dry kiln operator's manual. Madison, WI: USDA Forest Service, FPL Ag.
Handbook No. 188; 1991.
14. Summitt, R.
and Sliker, A. CRC handbook of materials science. Vol. 4. Boca Raton, FL: CRC
Press, Inc.; 1980.
15. USDA. Wood
handbook: wood as an engineering material. Madison, WI: USDA Forest Service,
FPL Ag. Handbook No. 72; 1974.
16. Woods, B.
and Calnan, C. D. Toxic woods. British Journal of Dermatology. 1976;
95(13):1-97.