BOARD FEET 
PER ACRE 
2000 
\WUh, Volume to leave 40 percent 
18 
Volume to cut 6O percent 
VZZZA 
BREAST—HEIGHT DIAMETER CLASS (inches) 
U.S.F.S.W.0.1940 
Ficure 6.—How a selective-logging operation in a typical old-growth northern hardwood forest provides for continued crops of timber. 
original forest, white pine prevailing on the better 
soils, jack pine on the poorest. 
The conifer swamp forests consisted of stands of 
black spruce, tamarack, and white-cedar in peat 
swamps. The largest swamps were in the eastern 
part of the Peninsula. 
Present acreage of pine is about 25 percent of the 
original; that of the spruce-fir type about 45 
percent; and of 
hardwoods, 72 percent. More than three-fourths of 
the virgin forest has been cut over (see colored map), 
and of this about 917,000 acres has been cleared for 
Of the 9.3 million 
acres of forest land uncleared, 1.2 
at least temporarily deforested (table 3) and is now 
occupied by sweet fern, grass, and brush. Some 
2.1 million acres has restocked with aspen and scrub 
The remaining 6 million acres is still of the 
original type but only 2,412,000 acres, or 25.9 per- 
of conifer swamps, 75 percent; 
villages, farms, and industry. 
million has been 
trees. 
299131°—41——-3 
is Classified as bear- 
In contrast, 55.6 per- 
cent of the forest area is deforested or is restocking 
cent of the whole forest area, 
ing trees of saw-timber size. 
with small trees. Compared with a managed for- 
est much too large a share of the acreage, even in 
this comparatively well-timbered part of the Lake 
States, is occupied by very young timber. 
For saw-timber production, the best remaining 
which total 
31%, million acres, including 11/, million 
acres of old growth. 
forests are the northern hardwoods, 
nearly 
The old-growth forests of 
sugar maple, yellow birch, hemlock, basswood, 
elm, etc., average more than 160 years and run 
11.4 M board feet, acre. The 
typical stand is uneven in both age and size, ranging 
lumber tally, per 
from seedlings up to mature trees 30 inches or 
(fig. 5). Such stands lend them- 
selves to a selective type of logging, in which the 
more in diameter 
larger and overmature trees are cut and the smaller 
