THE RED SPRUCE. 53 
spruce stands to eliminate spruce or balsam advance growth, and to 
reduce the percentage of balsam in the stand. Cuttings of this sort 
are indirectly remunerative, in the sense that they operate to shorten 
the rotation and thus bring the final yield nearer at hand ; but care 
must be taken to remove only what is necessary to accomplish the 
purpose of the operation, otherwise the cost will be too great. 
Liberation cuttings. — In the mixed selection stands, it often hap- 
pens that a large spreading maple or other hardwood is retarding 
the development of a group of young spruce. The removal of 
such a tree for that reason would be a liberation cutting. It 
will generally happen, though, that immediate financial considera- 
tions as to whether or not the tree is worth cutting will govern, 
and that such a cutting will be made a part of the regular logging 
operation. Similarly the removal of this class of tree from second 
growth stands will form a part of the operation of thinning. Because 
such trees are larger than the others in the stand, their removal 
may constitute a determining factor in making a thinning profitable. 
A liberation cutting will not often be made alone, although in cer- 
tain instances it will justify itself by making possible a large final 
yield. 
Thinnings. — Thinnings are particularly desirable in the dense, 
even-aged stands resulting from natural seeding. Such stands not 
infrequently have upwards of 4,000 trees per acre, with an average 
growing space of about 10 square feet per tree at 30 years of age. 
As compared to this, a planted stand spaced 6 by 6 feet apart would 
have but 1,210 trees per acre, with a growing space per tree of 36 
square feet. Even where the aggregate number of trees in the natural 
stand is less than that indicated, the tendency of spruce to germi- 
nate in clumps about the more favorable seed bed spots gives rise to 
a crowding which is every bit as undesirable as though the area were 
uniformly congested. 
On account of the extreme tenacity with which spruce hangs on 
when once it has its roots established in the soil, it is not able to free 
itself in the struggle for supremacy with anything like the facility 
of the less tolerant species. As a result, a long period of stagnation, 
in which both the height and diameter growth suffer, follows the 
closing of the crown cover. These stands, if allowed to continue in 
their overcrowded condition until they are from 50 to 60 years of 
age, will often contain as many dominant and intermediate trees 
to the acre as the planted stand would have to start with, and will 
be composed of small-topped, spindling trees, averaging not more 
than 6 or 7 inches in diameter; and not more than one-half of the 
total volume will be merchantable. Under such conditions, also, the 
stand can not be thinned profitably. The cost of getting out the 
amount of product to be secured from a first thinning in such a stand 
