202 THE PRINCIPLES OF HANDLING WOODLANDS 



viduals which ure defective, injured, dying, or dead, or 

 have exceptionally poor form. 



The characteristic of the method is that the trees pri- 

 marily chosen for cutting are in the subordinate part of 

 the stand; and then such others are taken as are required 

 by the special objects of management. Normally, the 

 suppressed trees are not left standing at all, unless it is 

 necessarv to remove one of the larger trees because of 

 some defect, and in that case subordinate trees are left as 

 a ground cover. 



The selection of the trees for cutting depends on how 

 severe a thinning is required. For convenience in svs- 

 tematizing the work, thinnings are classified into the fol- 

 lowing grades, based on the severity of the cutting: 



Grade A. Light, removing the dead and dying trees. 



Grade B. Moderate, removing all suppressed and, 

 in addition, the lower of the intermediate trees. 



Grade C. Heavy, removing, in addition, the re- 

 maining intermediate trees. 



Grade D. Very- Heavy, removing, in addition, many 

 of the co-dominant trees. 



A heavier cutting than Grade I) is called an accretion 

 cutting. (See page 21b. ) 



Principles Governing the Severity of Thinnings. — 

 The grade of thinnings to be used in any given case de- 

 pends on a variety of circumstances, of which the follow- 

 ing are the most important: 



1. Purpose of management. 



2. Condition of the stand. 



