BALSAM FIE, 
13 
RESIN CONTENTS. 
The complaints against the larger amount of pitch in balsam fir 
are somewhat strange in view of the fact that the actual resin content 
of balsam fir is less than that of spruce. Kesin in coniferous wood 
occurs normally in cells, of which the wood is built up as a house is 
built of bricks, and in the spaces between the cells, known as resin 
ducts, running vertically and horizontally through the wood. These 
resin ducts may be seen on cross sections ' of freshly cut wood as 
whiter or darker spots marked by exuded droplets of resin. On 
radial and tangential sections the ducts appear as fine lines or dots 
of different color. The difference in resin content of the different 
genera and species of the conifers depends mainly upon the number 
and size of their resin ducts. Balsam fir is one of the few conifers 
that lack resin ducts entirely, a thing which serves readily to dis- 
tinguish it from the spruces and pines. Resin is found in the wood 
of balsam fir only in the interior of the cells, where it occurs in the 
form of small droplets. The bark of balsam fir is very rich in resin, 
but after the former is rossed off the wood should be freer of resin than 
spruce, which contains resin ducts and resin cells. Therefore the 
pitch, which according to all reports is the greatest drawback to 
balsam pulpwood, must either come from the resin in bark left on the 
surface of the block or else is formed in the process of grinding, in 
which case it is not of a resinous nature. In either event, the presence 
of pitch is apparently not due to any property of the wood itself. 
A chemical determination of the resin contents of six spruce and of 
four balsam-fir sections made by the Bureau of Chemistry, United 
States Department of Agriculture, in 1904, gave the following 
results : 
Table 3. — Resin contents of spruce and balsam fir. 
SPRUCE. 
Moisture. 
Non- 
volatile 
resins. 
Volatile 
resins. 
Total 
amount 
of 
resins. 
Top 
Per cent. 
5.60 
5.66 
6.39 
5.85 
5.57 
5.62 
Per cent. 
0.88 
.92 
.76 
1.36 
2.33 
1.48 
Per cent. 
0.23 
.67 
.49 
.27 
.50 
.34 
Per cent. 
1.11 
1.59 
1.25 
1.63 
2.83 
1.82 
Middle section 
Butt section.. 
Top , 
Middle section 
Butt section 
Total 
10.23 
1.70 
BALSAM FIR. 
Butt section 
5.31 
5.06 
5.01 
4.80 
1.23 
.58. 
.77 
.67 
0.19 
.15 
.19 
.48 
1.42 
.73 
.96 
1-.15 
Middle section 
Butt section 
Middle section , — 
Total : : 
4.26 
1.06 
