48 BULLETIN 544, U. S. DEPARTMENT OF AGRICULTURE. 
SELECTION CUTTINGS. 
On account of the tolerance of spruce, it is well adapted to a selec- 
tion system of management by which only the older trees of the 
main stand are removed and the necessary conditions thus estab- 
lished for the development of a new young growth. When this sys- 
tem is strictly carried out, the forest should be cut over annually, and 
only the very oldest and largest trees and those of least promising 
growth removed. In forests constituted as ours are at present, such 
a procedure would be impossible of accomplishment under any other 
than State ownership, which might put other considerations above 
revenue. 
Cutting to a diameter limit, now quite generally practiced by lum- 
bermen in the spruce regions, is a modification of the selection system 
by which a sufficient yield to make the individual cutting operations 
profitable is secured periodically. The amount cut each period and 
the interval between the successive cuttings vary, of course, with 
the diameter limit used. 
In order to obtain satisfactory results under this system, a careful 
scrutiny is required of those trees immediately above and below the 
set diameter limit that their relations to others and to the best inter- 
ests of the stand to be left may be ascertained, A fixed diameter 
limit is used in making computations to forecast the yield; but its 
application by "rule of thumb" in actual practice may defeat the 
purpose of the system. In the woods the diameter limit is best used 
simply as a guide. In general the largest trees should be cut, since' 
their rate of growth is below that which would make their retention 
a profitable investment. They are likewise occupying space which 
would be more profitably used by younger and more rapidly growing 
trees. Approaching the diameter limit there are trees both above 
and below the established limit which should be cut because they 
have a poor crown, are stunted, or otherwsie defective, so that their 
present worth would be lost if they were to be left until the next 
cutting. On the other hand, trees above the prescribed diameter 
limit which give every indication of being in thrifty growing condition 
should unquestionably be left, since their worth will be materially 
enhanced by allowing them to remain until the next cut is made. 
Trees of inferior species, as balsam and most of the hardwoods, which 
are interfering with the best development of the spruce, should be 
cut whenever possible. 
Thus while the prescribed diameter limit may be 14 inches, the 
approximate minimum size to be taken may be 5 inches. Other 
things being equal, this minimum size will depend upon the market 
and the object of management. To insure a utilization of at least 
two-thirds of the stem height, no sound spruce tree should be cut for 
lumber smaller than 10 inches in diameter at breastheight and for 
pulp none smaller than 5 inches in diameter. These minima should 
