40 WESTERN YELLOW PINE IN ARIZONA AND NEW MEXICO. 
QUALITY, WEIGHT, AND STRENGTH. 
The wood of western yellow pine is heavy, hard, and brittle, but 
not coarse-grained. The sapwood resembles the eastern white pine, 
is easy to work, and has been widely used as a finishing material, 
since it is light colored and velvety. On the market it has quite a 
reputation as “ western white pine.” | 
According to Sargent the specific gravity of the wood is 0.4715 
end the ash 0.85. Lumbermen figure the shipping weight of 1,000 
feet board measure of logs to be 9,250 pounds. In October and 
November, however, the weight may fall as low as 8,250, and in July 
and August 1t may rise to a maximum of 10,000 pounds. Dry, sound 
lumber weighs from 2,500 to 3,000 pounds per 1,000 board feet. 
Table 21 shows the results of tests by the Forest Service on 15 
western yellow pine sills, 5 inches by 8 inches by 16 feet, cut from 
first and second grade common lumber about April 1. The sills 
were tested in bending with the load applied at two points one-third 
of the span from each end. At the conclusion of the bending test 
specimens 2 feet long were cut from the uninjured portion of each 
sill, and tested under compression parallel to grain. In the com- 
pression test the maximum load was the only reading taken. Crush- 
ing tests gave very uniform results. In 13 out of 15 car sills failure 
was due to knots. In the crushing tests 10 failures occured at knots. 
In all the tests the strength of air-dried material is evident. 
Comparison of the bending strength of western yellow pine sills 
with those of Douglas fir sills of the second grade* gives a value of 70 
for the pine on the basis of 100 for the fir. In the same way the 
stiffness or modulus of elasticity of the pine is 68 per cent that of 
the fir, and the crushing strength 74 per cent. The dry weight of the 
fir upon which the tests were made was 27 pounds per cubic foot, and 
the rings per inch about 8. 
Tests made upon western yellow pine car sills were very few, and 
the results must, of course, be regarded as tentative. 
TABLE 21.—Results of laboratory tests on car sills of western yellow pine. 


Green ma- | Air-dry ma- 
terial. terial. 
IMOISCUT OR ie a cra te en eae eo ee) ee eres tees Beare agar ee mene per cent. . 38.2 10.7 
Rings per inehts.2 5 ces ase rae eso ao eee ee Ane ete eras 12.8 iS 
Per Cent Ol Sap gist ok qa eter ears aie eeic le ire tetas Sete Sen = eres ems reat PH feria SAEs oc 
Specificwrawity, Gry qs shoe See eee See Bee eee Bee eee ee $08 [etcaee scenes 
Wieichitipercubicdtootasitesve teases seer asses eae eee eer pounds. - 32.8 PAGAL 
Wierphitipericybictoobiowentdiny ees saa eee ee eee ee area donee 23.8 22.4 
PDETYSERESSiaie) AS HIG MITm eye ete eee ieee Ibs. per sq. in... 2,259 2,830 
Modulus ofripture:2. 2c aace Se coc cene eens ee ee ee anc em eer dom 3, 223 4,702 
Modulusiofielastictty.u 5 .22ae ose eee ne eer ne eee ate ee ae ees doz. : 962, 000 1,311 ; 000 
WIaStie resilience ee. Ba Se ae te Ee Oe OS ee eee .4 A 

1Three grades of Douglas fir car sills are usually designated, select, merchantable, and 
second. 


