TESTS OF ROCKY MOUNTAIN WOODS FOR TELEPHONE POLES. 11 
There seemed to be no consistent difference in the behavior of 
straight and spiral grain poles. 
•The typical failure of the western red cedar poles was a splinter- 
ing tension about 2 feet from the load point. The wood separated 
easily along the annual rings, and the splinters were long and numer- 
ous. Probably due to this quality, as well as to the depth of checks, 
three poles failed in longitudinal shear, and in two others shear 
occurred after the maximum load had been passed. 
In the air-seasoned lodgepole pine poles there were 18 tension 
failures and 4 failures from longitudinal shear. Of the 18 tension 
failures, 9 were of the splintering type characteristic of the cedar 
poles and 9 were simple tension failures; that is, without the exhibi- 
tion of brittleness or unusual splintering. 
The typical failure in fire-killed lodgepole pine was a simple ten- 
sion close to the load point. The wood often had a rather brash 
appearance, and, except for two poles, did not splinter to any extent. 
One pole was brittle, failing near the center, and one failed by longi- 
tudinal shear after the maximum load had been passed. 
In general the fire-killed Engelmann spruce poles failed in the 
same manner as the fire-killed lodgepole pine. Two poles had brittle 
tension failures, and there were no longitudinal shear failures. 
The fact that 9 of the 42 air-seasoned and only 1 of the 40 fire- 
killed poles failed by longitudinal shear might seem at first to indi- 
cate that the checking of the poles cut from green timber is deeper 
than that occurring in the more slowly drying fire-killed poles. The 
fact, however, that the average shearing stress of the cedar proved 
to be about 15 per cent lower than that of the other species, and fur- 
ther that the moduli of rupture in bending of both green-cut shipments 
were higher than those obtained in both fire-killed shipments, shows 
that there was a greater chance for shear failures in the air-seasoned 
material than in the fire-killed, aside from any difference in the 
manner of checking. 
Compression of the upper fibers, as shown by wrinkles on the top 
of the pole, occurred some time before the maximum load was reached. 
There was usually a noticeable increase in the bend of the load- 
deflection curve after compression became visible. 
