GROUND-WOOD PULP. 41 
THE HEMLOCKS. 
Eastern hemlock (Tsuga canadensis) requires a considerable 
amount of power for the production of satisfactory pulp. The wood 
must also be of fairly small diameter and of very good quality. 
Even under the best conditions, eastern hemlock pulp does not pre- 
sent a good appearance; the fibers are short, and it has a decided 
reddish tinge. Moreover, it is very hard to produce pulp which 
will not crack along the edges when the laps are folded. However, 
even with the handicap of short fibers, a pulp satisfactory for news- 
print purposes can be produced. The yield from eastern hemlock 
is approximately 2,030 pounds per hundred cubic feet of solid rossed 
wood (370 pounds less than from an equal amount of white spruce), 
though the same ratio would not be evident if the basis were a cord 
of rough wood. 
Western hemlock (Tsuga heterophylla) can be ground at much 
higher pressures and with a sharper stone than eastern hemlock. 
The pulp produced is of very good quality and 
aside from its grayish color compares well with — 
white spruce. It is far superior to that from 
eastern hemlock. The yield is about 2,160 
pounds per hundred cubic feet of solid rossed 
wood, or 240 pounds less than that from white 
spruce, though the bark of western hemlock is 
much heavier than that of the latter species. 
THE LARCHES. 
Tamarack (Larix laricina) produces a very 
good quality of pulp with a reasonable amount 
of power. Incolor, however, the pulp is a de- 
eidedly grayish green. It would probably serve for news-print paper 
if used with spruce sulphite or mixed with spruce ground wood. In 
any event, it could be used for wrapping paper. ‘The yield is approxi- 
mately 2,620 pounds per hundred cubic feet of solid rossed wood, or 
about 220 pounds more than from an equal amount of white spruce. 
Western larch (Larix occidentalis) yields a very inferior pulp. The 
product is difficult to operate on the wet machine, and the pulp 
stone must be rough, but not sharp, to secure the best results. In 
other words, the pulp must have coarse fibers and a relatively large 
number of shives. The color, a decided brown, is objectionable. 
The yield from western larch was only 2,100 pounds per hundred 
cubic feet of solid rossed wood, though on the basis of the dry weight 
of the wood it should have been at least 2,300 pounds. This differ- 
ence is probably due to the high proportion ‘of the wood substance 
that is soluble in water and to the brittleness of the heartwood, so 
that a large percentage of the yield is lost in the white water. 
Fic. 29.—Noble fir (Abies 
nobilis). 
