may be attained are of course de- 
pendent on the rate at which cutting 
proceeds, the type of stands in which 
it is concentrated, and the effective- 
ness of fire protection. 
Tf Forest Practice Becomes More Intensive 
The maximum average annual 
attainable under present 
inten- 
growth 
standards of utilization and 
siveness of forest practice (4.5 billion 
board feet) is but little more than 
half the annual volume depletion the 
forests of the region have undergone 
in the recent past. ‘Thus, the extent 
to which growth can be increased 
through improved forest practice will 
be a controlling factor in determ- 
ining the level at which forest industry 
DISTRIBUTION OF REGIONAL GROWTH (PERCENT) 
can be continuously maintained, 
assuming reasonable stability of 
demand. 
By increasing the rotation assumed 
for realizable mean annual growth 
(100 years for all sites) to the tech- 
nical rotation ages (ranging from 
100 to 200 years, depending on site), 
the end value of realizable growth, 
based on a 55-percent stocking of 80 SOUTH 
percent of commercial conifer sites, gees 
would be increased from 4.5 to 4.8 
billion board feet. Obviously growth 
WILLAM- 
OREGON GRAYS PUGET | DOUGLAS 
T ] 
COAST i ee HARBOR SOUND FIR 
UNITS UNIT UNITS | UNIT UNITS REGION 
1 
could be further increased by extend- 
ing the timbered area and raising 
stocking to a greater percentage, 
through increased efficiency of fire 
control, seeding and planting of devastated 
sites, interplanting on poorly stocked sites, and 
adoption of logging methods that will insure prompt 
By 
increasing the average stocking of forest sites, mean 
and adequate regeneration for cut-over areas. 
annual increment for the region could be increased 
to the estimated potential annual total of 8.2 
billion board feet, which assumes average stocking 
of all forest sites at 75 percent of normal, the esti- 
mated maximum attainable over extensive areas. 
63 
Ficure 17.—Distribution of potential annual conifer growth (by Scribner rule, in 
32-foot logs to 12-inch top) of trees 15.1 inches d. b. h. or more on commercial forest 
land in the Douglas-fir region, by survey unit and site class 
From the foregoing computations of board-foot 
growth it is obvious that if the more intensive forest 
practice and higher standard of utilization were 
adopted, about 50 percent more material could be 
obtained from growing stands than is obtained 
under the present standard. The reductions in 
technical rotation age that would be effected by 
this change are indicated in table 55. 
Under 
yields through utilization of material cut in thin- 
existing market conditions, increased 
