SITKA spruce: uses, growth, management. 7 
Because of its light weight, combined with strength and tough- 
ness, Sitka spruce is the most desirable and most generally used wood 
for such airplane parts as wing beams, struts, longerons, ribs, and 
plywood parts. Although red, white, and Sitka spruce do not differ 
greatly in strength properties, the last species, on account of its 
greater size and consequently its greater proportion of clear lumber, 
is a more important source of aircraft material than the other two. 
Because of this and the relatively large supplies of virgin timber still 
remaining, Sitka spruce w T ill probably for many years be a very im- 
portant species in the aircraft industry, notwithstanding the fact 
that the supply is far from the centers of manufacture. 
Because of the resonant quality of the wood, its even structure, the 
absence of vessels, the extremely fine and regularly distributed medul- 
lary rays, and the straight and long fibers, spruce generally is con- 
sidered to be the best wood for piano sounding-boards, as well as for 
musical instruments generally. Sitka spruce yields a large propor- 
tion of clear lumber and wood of selected quality for this purpose, 
but its rapid growth tends to lessen the resonant quality in compari- 
son with the slower growing eastern species. 
The wood is not durable in contact with the soil or when exposed to 
weather. It is less suitable for piling in salt water tha.n are other 
species, because of its greater susceptibility to the ravages of the 
teredo, which may destroy it in one or two years. 
For the manufacture of white paper pulp by either the mechanical 
or the chemical process, spruce is the leading wood used. It is soft, 
white, and nonresinous, and its fibers are longer, more flexible, and 
stronger than those of most woods. Containing a maximum percent- 
age of cellulose, it gives a high yield by the chemical process. Al- 
though there are several species of 'spruce, no marked difference is 
noted in the pulps manufactured from them. A comparison of the 
character and uses of the pulp made from Sitka spruce with that 
made from white spruce, a wood that can be considered standard for 
pulping by the sulphite, sulphate, and mechanical processes, indicates 
no practical difference. 
Because of the long distance to the large paper markets of the East, 
the utilization of Sitka spruce for paper manufacture is relatively 
small. Of the domestic spruce consumption in the United States in 
1918 for the manufacture of paper, 35,385 cords, or 1.6 per cent, was 
Sitka spruce from the forests of Washington and Oregon. British 
Columbia utilizes about half as much Sitka spruce for this purpose 
as do the States of Oregon and Washington. Other species, includ- 
ing western hemlock, white fir, cottonwood, and Douglas fir, are util- 
ized on the Pacific coast in the manufacture of pulp, but Sitka spruce 
represents about 15 per cent of the total. 
