THE BED 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 

 miiformly 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 



