In the base projections, the oldest-first option was assumed 
with the following protection against liquidating all of the 
old stands on public, forest industry, and corporate owner- 
ships: On these ownerships, the minimum harvest age for 
both upland and bottomland hardwood stands on poor sites 
was set at 90 years. On the farmer and other individual 
private ownerships, the minimum harvest age for both 
upland and bottomland hardwood stands on poor sites was 
set at 50 years. 
On forest industry and corporate ownerships, the minimum 
harvest age for pine and mixed pine—hardwood stands was 
set at 20 years. On these ownerships, the minimum harvest 
ages for hardwoods were 35 years for high sites and 40 
years for medium sites. On the farmer and other individual 
ownerships, the minimum harvest age for pine stands was 
also set at 20 years but ranged from 35 to 50 years for 
mixed pine—hardwood and hardwood stands. On public 
lands, minimum harvest ages ranged from 35 to 55 years 
for pine and mixed pine—hardwood stands. The minimum 
harvest age for hardwood stands on high and medium sites 
on public land was set at 60 years. 
In the South Central region, the minimum harvest age was 
increased by 5 years for all ownerships and management 
types. This decision was based on an assumption of slightly 
longer rotations, on the average, and more emphasis on 
sawtimber rather than pulpwood production. 
Thinnings—In those management intensities with commer- 
cial thinnings, it was assumed that one-third of the inventory 
would be removed in one thinning. It was also assumed 
there would be no overall increase or decrease in total yield 
as the result of thinning. The amount removed during 
thinning was subtracted as a constant reduction at subsequent 
ages in the yield tables. In those management intensities 
calling for thinning of pine plantations, thinning was 
assumed at age 20 on all private lands if the stands had not 
been harvested; on public lands the thinning age was set 
at 30 years for pine plantations. 
Thinnings of natural pine stands on private lands were 
assumed at age 25 on high sites and at age 30 on medium 
sites. Time of thinning in natural pine stands on public land 
ranged from 30 to 40 years of age. 
There are, of course, other assumptions underlying the 
projected changes in timber resources presented below. The 
most important of these are described in the appropriate 
places in the following text. 
Recent and Projected Softwood Timber Supplies 
Timber supplies—the volume of timber harvested or avail- 
able for harvest in the future—are one of the important 
measures of resource change. Timber supplies are all round- 
wood products, regardless of source. They include industrial 
roundwood products such as sawlogs, veneer logs, pulp- 
wood, other industrial roundwood products, and fuelwood. 
Although most timber supplies come from growing stock, 
substantial quantities come from other sources: (1) trees 
smaller than 5.0 inches d.b.h.; (2) the stumps, tops, and 
limbs of growing-stock trees; (3) rough and rotten trees; (4) 
dead trees; and (5) trees that grow on land other than 
timberland. 
Southwide Trends 
Between 1952 and 1962, annual softwood supplies (harvests) 
from the South declined from 3.1 billion to 2.8 billion 
cubic feet, or by 7 percent (table 3.15, fig. 3.17). A 30- 
percent decrease in softwood sawlog production more than 
offset a 35-percent increase in the annual production of 
softwood pulpwood. Hundreds of small portable sawmills 
and many larger stationary mills closed down in this period 
as the region experienced a major shift from lumber to pulp 
and paper production. 
Between 1962 and 1984, annual softwood supplies climbed 
to 5.0 billion cubic feet, an increase of 77 percent. This 
increase is attributed to further expansion in the pulp and 
paper industry, a revitalized lumber industry, and the estab- 
lishment and development of the pine plywood industry. 
Over the past 30 years, other private timberland has been the 
primary source of softwood timber supplies in the South; 
however, the proportion coming from this source has been 
declining (fig. 3.17). In 1952, these other private timber- 
lands provided about 71 percent of the softwood supplies. 
This proportion has decreased to 58 percent. In 1952, 23 
percent of harvested softwood timber came from forest 
industry lands; these lands now provide about 35 percent. 
Over this period, public timberlands have provided about 7 
percent of the softwood supplies. 
In the base projections, softwood timber supplies (harvests) 
will rise to 5.8 billion cubic feet of roundwood by 2000. 
This represents a 15-percent increase over current levels. 
Forest industry timberland is expected to provide most of 
this increase as softwood supplies from other private 
timberland begin to level off. Between now and 2000, 
annual softwood supplies from forest industry land are 
projected to increase by 28 percent, from 1.8 billion to 2.5 
billion cubic feet. 
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