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Methods and Specifications 
279 
Standards of Measurement 
ment of the volume of standing timber, so that 
estimates would be stable and could be cor- 
related with estimates for other regions and ad- 
justed to meet changing economic conditions. 
Standards were defined that conformed as far as 
practical with generally accepted concepts of 
utilization practices appropriate to current condi- 
tions. Inventory, growth, and depletion data are 
given in board feet, log scale in the body of this 
report. Lumber-tally equivalents are found in the 
appendix. 
Timber-volume estimates were made in board 
feet, log scale, according to the Scribner Decimal 
C rule, and in cubic feet. The board-foot esti- 
mates included only the stems of living trees that 
would make at least one log meeting the following 
specifications: Conifers other than ponderosa pine 
and sugar pine, 32 feet long, 12 inches in diameter 
inside bark at the small end; ponderosa pine and 
sugar pine, 16 feet long, 10 inches in diameter 
inside bark at the small end; hardwoods, 8 feet 
long, 10 inches in diameter inside bark at the small 
end. Practically, this amounts to making the 
minimum specification for conifers other than these 
two pines the 16-inch diameter class (15.1 to 17.0 
inches d. b. h.)? and that for ponderosa pine, sugar 
pine, and hardwoods the 12-inch diameter class 
@aEtetost3:0imehes d: b: h:) 
Allowance was made in the volume estimates for 
decay, defects, and such breakage as is inevitable 
in logging. In other words, the estimates are for 
the net volume usable in saw-timber operations 
under good utilization practices. 
|: WAS necessary to fix standards of measure- 
3“T). b. h.” signifies diameter at breast height (41% feet 
above average ground level) outside bark. 
KE 
Probably the standards of utilization employed 
- in the survey estimates are slightly more intensive 
for the more valuable species, and considerably so 
for the less valuable species, than the average 
utilization standards of present-day saw-timber 
operators, Owing chiefly to the inclusion of trees 
as small as the 16-inch diameter class. 
Cubic-foot volume was computed for the sound 
wood of stems only, from stump to 4-inch tip inside 
bark, limb wood and bark excluded, of all trees of or 
above the 6-inch (5.1 to 7.0 inches) diameter class. 
The estimates cover all timber areas, including 
farm woods, outside the platted limits of muni- 
cipalities. 
In order to obtain satisfactory estimates of volume 
of standing timber it was necessary to have for 
each of the commercial saw-timber species an 
accurate volume table that could be applied 
throughout the region. Investigation and check of 
the existing tables showed that some of them could 
be used as they were and others could be made 
usable by adjustment and extension to include 
larger trees, but that for some species new tables 
would have to be made. Volume tables used for 
the principal species are described in the appendix. 
Species and Tree-Size Classification 
An estimate of total volume of living timber was 
made and recorded separately for every species that 
usually attains saw-timber size and character and 
that was present in commercial types in quantity 
measurable according to survey standards. Also, 
an estimate of total volume of dead timber was 
made and recorded for Port Orford white-cedar 
(Chamaecyparis lawsoniana), western redcedar, and 
Alaska yellow-cedar (C. nootkatensis). (Owing to 
their durability and resistance to decay, dead trees 
