Western hemlock is of somewhat, but not much, slower growth when
coming in on open land as an even-aged stand. No yield table based
on the same merchantable standards as the fir table quoted has
been prepared, but the following is fairly safe to include all
trees 14 inches in diameter used to 12 inches in the top: At 50
years, 2 M per acre; at 60 years, 22 M; at 70 years, 33 M; at 80
years, 40 M. The absence of a 40-year figure, and the sudden jump
between 50 and 60 years, is because very few hemlock trees reach 14
inches at 50 years, but a large number of 12 and 13-inch trees pass
into that class during the ten years following. Any yield figures
for an even-aged forest show a similar jump at the point where the
stand as a whole reaches the determined minimum merchantable size.
For the same reason these hemlock figures are not very far less
promising than those given for fir, for at corresponding ages the
latter include 12 and 13-inch trees and all trees are considered
merchantable to a top diameter of 8 inches.

SPRUCE

Since no systematic study of Sitka spruce second growth has been
made, it can only be predicted from knowledge of its habits that
while in favorable situation it will yield as heavily as Douglas
fir, in other localities its growth in early life is slower and
less regular, making it less likely to produce a good crop before
the carrying charges become burdensome. If this proves true, taxation
rates and land values will be extremely important factors, offset
to some degree by a smaller fire hazard and the probability of
high stumpage.