46 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 



