A4 BULLETIN 1496, U. 8. DEPARTMENT OF AGRICULTURE 
TABLE 8.—Average per acre distribution of trees on 77 acres of birch-beech- 
maple forest 
E bid Number | Percent- 
Diameter breast high in inches of trees | age distri- 
per acre | bution 
ot (Sa aa ed pe el ie SEB A Se 5 2h a IY BOY Dv ele ete 8 ae O18 eee fe lak BON BE a el ts yee 8 2 168 64 
7 All Peery Seen eg Pea Se eee Se cee Sa es Ae ied Oe eee yO Se a oe ee ie a ee 36 14 
AOPATNI GOV CY ese oe ee ee ee peiecboheh oped Tee ate Bees Leda tp tek. asp Non cent a ee 59 22 
Wotal- 202 2 oo so are SS a aI |e A al i eae 263 100 
If only trees of saw-log size are cut, and especially only trees 
which can be economically logged, the remaining stand will contain 
204 trees an acre 2 to 11 inches in diameter, inclusive—or 216 trees 
between 2 and 13 inches—capable of producing a second cut of saw- 
log timber equal to the first cut in 50 to 60 years, and subsequent 
cuts at similar intervals. The higher the diameter limit below 
which the trees are left uncut, the shorter the period within which 
a second cut may be expected and the higher the grade of lumber 
which may be obtained. 
In felling the larger trees a certain amount of damage is inevi- 
table. Yet with reasonable precaution much unnecessary breakage 
can be avoided. In logging a hardwood forest in the Upper Penin- 
sula of Michigan in the summer of 1926 and removing only the 
larger trees, about five standing trees per acre were broken and had 
to be cut down, and these were mostly trees between 6 and 7 inches 
in diameter. If on an average 204 trees an acre below 12 inches 
in diameter are left in logging, allowing even 10 young trees to be 
broken down in felling the larger trees, there should still remain 
194 trees ranging from 2 to 11 inches in diameter to form the basis of 
a second cut. If these young trees are to grow up to saw-log size 
within a short time, they, of course, should not be cut for ties, mine 
timber, or chemical wood. If all trees below 12 or 14 inches are left, 
no further provision for seed trees is necessary. 
Frequently there occurs within the hardwoods some white pine. It 
is generally desirable to increase the proportion of white pine in the 
second-growth hardwood stand ‘because of its higher value and 
faster growth. Some of the white-pine trees, even above 12 inches 
in diameter, should therefore be left as a source of seed. It is not 
advisable, however, to leave very large, old white pine, because the 
investment in such trees and the hazard of losing them in the course 
of the next two or three decades are too great. 
PARTIAL OR “SELECTIVE” CUTTING IN OLD HARDWOOD STANDS 
The amount of old mature hardwood timber left in the Lake 
States in private ownership is comparatively small. Its area has 
been estimated at 10,100,000 acres for the entire region, or 3,500,000 
acres for Minnesota, 2,100,000 acres for Wisconsin, and 4,500,000 
acres for Michigan. The life of the industry based on the old timber 
is estimated at less than 20 years. In some localities, at the present 
rate of cutting, the timber will be gone much sooner. Most of this 
timber is from 100 to 250 years old. The same sizes will never be 
