8 BULLETIN 1437, U. S. DEPARTMENT OF AGRICULTURE 
THe following tabulation 3 shows the actual and comparative 
properties of red alder, as determined by the Forest Service. East- 
ern white oak (Quercus alba) is the wood generally used as a basis 
for comparison of properties. The composite values given are 
weighted averages of several values derived from different kinds of 
strength tests. (Fig. 3.) It will be noted that the hardness value 
of red alder is low compared with white oak, while the stiffness value 
is high. As a beam or post red alder is nearly four-fifths as strong 
as white oak. 
Locality where grown Washington 
Weight per cubic foot : 
Green pounds__ 46 
Air-dry, 12 to 15 per cent moisture content do 28 
Kiln-dry, 8 per cent moisture content do 27 
Specific gravity, based on oven-dry weight and volume when green 0.37 
Specific gravity, based on oven-dry weight and volume when oven-dry 0. 43 
Specific gravity, based on oven-dry weight and volume when air-dry 0. 42 
Shrinkage from green to oven-dry condition : 
In volume per cent 12. 6 
Radial do 4. 4 
Tangential do 7. 3 
Comparative shrinkage (one-third of sum of tangential, radial, and 
twice volume) per cent 12. 3 
Strength in bending at 12 per cent moisture content : 
Modulus of rupture pounds per square inch 9, 3S0 
Relative strength compared with white (white oak=100) 62 
Strength in compression parallel to grain at 12 per cent moisture content : 
Maximum crushing strength pounds per square inch 5, 630 
Relative strength compared with white oak (white oak=100) 77 
Shearing strength parallel to grain at 12 per cent moisture content : 
Shearing strength pounds per square inch 1, 045 
Relative shearing strength compared-' with white oak (white 
oak=100) 50 
Composite values : 
Strength as a beam or post 8,214 
Compared with white oak (white oak=100) 79 
Hardness 456 
Compared with white oak (white oak=100) 44 
Shock-resisting ability 7. 33 
Compared with white oak (white oak=100) 57 
Stiffness 1, 375 
Compared with white oak (white oak=100) 91 
Table 1 compares the relative properties of red alder with those 
of several woods that are often put to the same uses. For turned 
parts alder's greater stiffness is of considerable advantage, and among 
the hardwoods it is excelled in this respect only by red gum (Liquid- 
amibar stymciflua) and yellow poplar (Liriodendron tulipifera), 
and only slightly by these. For posts, stretchers, and other turned 
parts alder has to a large extent replaced red gum in the furniture 
industry of the Pacific Northwest. In ability to resist shock alder 
is exceeded only by red gum, big-leaf maple (western), and Douglas 
fir. As a beam or post Douglas fir alone shows a large excess over 
alder in strength. 
Alder is proving the equal of basswood (Tilia glabra) and yellow 
poplar for colors in high-grade veneered panels. In general woods 
3 Based partly on data taken from the following bulletin : Newlin, J. A., and Wilson, 
T. R. C, Mechanical Properties of Woods Grown in the United States. U. S. Dept. Agr. 
Bui. 556, 47 pp., illus. 1917. Partly on subsequent investigations by the Forest Prod- 
ucts Laboratory, Madison, Wis. 
