92 



THE SELECTION METHOD 



assigned to age classes on the basis of size. For this purpose 

 tables showing the average age of trees of different diameters 

 can be made by analysis of the growth of felled trees. 



A diameter limit may then be established with the under- 

 standing that trees below this size are to be reserved and 

 those above cut. This should not be made a rigid limit but 

 should be apphed discriminatingly, certain trees above the 

 limit being reserved and some below the limit cut. In the 

 parallel columns given below the chief reasons for cutting 

 below or leaving trees above the Umit are summarized. 



Trees may be left above the diameter Trees may be cut below the diameter 



limit when: 

 I. Exceedingly thrifty and growing 

 fast in volume and in value. 



2. Standing in groups of smaller 

 trees and liable if cut to cause 

 windthrow or breakage among 

 these trees. (See Fig. 30.) 



3. A large seed tree is needed in or 



on the edge of an opening. 

 (See Fig. 31.) 



4. Needed for aesthetic reasons. 



5. Required to protect soil condi- 



tions or seedlings. 



Umit when: 



Unthrifty, slow growing and 

 likely to decay or be killed be- 

 fore another cutting and those 

 at present defective. 



So exposed that if left they will 

 be windthrown or broken in 

 feUing neighboring trees. This 

 is apt to occur in case of tall, 

 slender individuals growing in 

 a group of larger trees. 



By so doing the composition may 

 be improved or the rate of 

 growth of more promising 

 neighbors increased. (See 

 chapters on Intermediate Cut- 

 tings.) 



The great temptation in cutting timber under the selection 

 method is to take too much; in other words to cut trees too 

 young or too small and thus deplete the younger and middle 

 age classes. 



This temptation exists because the young trees are inter- 

 mingled with the old age classes instead of being segregated 

 on separate areas as in the other high forest methods. Even 

 though the merchantable trees below the diameter limit are 



