METHODS OF MAKING THINNINGS 175 



possible, are selected from among the best dominant trees. 

 After the selection of the final crop trees has been accom- 

 plished a heavy thinning is made, taking out all trees of any 

 crown class which are interfering with the development of 

 the final crop trees. Such a cutting frequently involves the 

 removal of dominant trees and the leaving of openings in the 

 main canopy which do not close for several years. To pre- 

 vent undue exposure of the site as a result of the heavy thin- 

 ning the overtopped trees are left standing to furnish a pro- 

 tective cover. From among the overtopped trees the sup- 

 pressed, i.e., those already dead or dying, are culled in a light 

 thinning to secure utilization before the trees become worthless. 



Where the final crop trees stand fairly far apart the first 

 heavy thinning, in accomplishing its purpose of freeing on 

 all sides the selected trees, may leave dominant, co-dominant 

 or intermediate trees not interfering for the present with the 

 selected individuals. In the subsequent thinnings all trees 

 (not final crop trees) in the upper crown classes would be 

 removed leaving eventually only the final crop trees with an 

 understory composed of the oppressed class. The volume re- 

 moved corresponds to that taken out in Grade D under the 

 ordinary method. 



The advantages of the French over the ordinary method 

 are that: 



(a) Bigger timber can be produced in the same time or 

 timber of the required size in a shorter time. This is made 

 possible by the freedom for expansion afforded the crowns of 

 the selected trees. As individuals they have more room than 

 would be possible under the ordinary method because the 

 overtopped stand preserves a close cover and obviates the 

 necessity of the dominant stand maintaining a complete 

 canopy. 



(b) The method gives higher immediate cash returns from 



