falls far above or below that.

An attempt to reproduce here any considerable number of growth
and yield tables would be of doubtful use without more space than
is allowed to explain how they are made and used. There are many
technicalities, both mathematical and silvicultural, and unfortunately
most of the available figures for the Northwest, obtained by the
Forest Service, have not been generalized enough for wide popular
value. This is particularly true of yield tables which necessarily
require assuming standards of merchantability. While the best western
white pine table assumes that by the time a new crop is cut 7-inch
white pine will be salable, the best fir table was worked upon
a 12-inch diameter basis. Obviously this would show an unfairly
greater yield of a pine forest containing trees between 7 and 12
inches and be very misleading in calculating financial results at
the same age and stumpage rates; yet without the original data
there is no way of reducing both tables to the same basis. As an
example, however, to indicate how the financial possibilities of
second growth can be arrived at if a systematic study is made,
let us take the Douglas fir figures referred to.

DOUGLAS FIR

These are exceedingly reliable. Measurements were taken by the Forest
Service of practically pure fir on about 400 areas in thirty-five
different age stands from 10 to 140 years old, ranging along the
western Cascade foothills from the Canadian line to central Oregon.
Since reforestation investment is likely to be confined mainly to
the more promising opportunities, only such growth was measured
as gave an average representation of the better class of the two