26 BULLETIN 67, U. S. DEPARTMENT OF AGRICULTURE. 
CONCLUSIONS. 
The tests on poles and specimens cut from them show that — 
1. Air-seasoned lodgepole pine poles cut from live timber in Mon- 
tana were fully equal in strength to the cedar poles tested. In actual 
stress developed they were superior, but on account of the greater 
taper of the cedar poles this advantage was lost in a comparison based 
on equal top diameters, the dimension usually specified. 
2. Cedar poles were superior to the pine and spruce poles cut from 
a fire-killed area in Colorado in maximum load developed. The three 
shipments were, however, practically equal at the elastic limit. Were 
the native poles to be used in place of cedar without change of specifica- 
tions, it would follow that the factor of safety would be reduced one- 
fifth for conditions at failure, but would remain the same for stresses 
at the elastic limit. 
3. The fire-killed pine, after standing 10 years, did not show deteri- 
oration to any appreciable extent when compared to seasoned lodge- 
pole pine cut from representative live trees in Wyoming and Colorado. 
The advantage in strength of the material from the lodgepole pine 
poles from Montana can be accounted for by the fact that it was above 
normal in weight — at least for lodgepole pine from the southern part 
of its range. 
4. The ratio between the strength of the poles and the strength of 
the clear material cut from them is not constant for the different 
kinds of wood. This " efficiency " factor varied from 0.74 to 0.48 of 
the strength of the clear wood when the comparison is made as tested, 
and from 0.98 to 0.65 when compared on the basis of values estimated 
to represent the same moisture condition in the small pieces as existed 
in the poles when tested. The values were highest for the cedar and 
lowest for the spruce, the pine representing an average for the three 
species. 
POLE TESTS BY THE PACIFIC TELEPHONE & TELEGRAPH CO. 
The Pacific Telephone & Telegraph Co. made tests on 81 poles of 
western red cedar and Port Orford cedar at the pole yards of the 
Western Electric Co. near Kichmond, Cal. These poles" were 25 
and 30 feet in length, with 6, 7, and 8 inch top diameters, and 35 feet 
in length, with 7, 8, and 9 inch tops. 
The method employed in these tests makes it impossible to make 
any accurate comparisons of stress values with those obtained in the 
Forest Service tests. In the telephone company's tests stresses are 
figured for the point of failure, while the Forest Service tests are 
figured for the load point or ground line, theoretically the point of 
greatest stress. 
In the telephone company's tests the poles were tested horizontally, 
with 6 feet of the butt end of the pole held firmly between four 12 
