INTERMEDIATE CUTTINGS 89 



duced faster under the French method of thinning than under 

 that ordinarily used. Up to the present time there is no ade- 

 quate data to conclusively prove this. With poor markets the 

 method may sometimes be employed when another could not, 

 since some larger-sized material is secured from the heavy cutting 

 in the dominant and codominant classes, while the lower classes, 

 furnishing cordwood principally, are left uncut. 



Silviculturally the lower classes of trees assist in forcing the 

 height growth of the chosen trees, and furnish a good cover to 

 the soil which is in this way better protected than in Grades C 

 and D thinnings as ordinarily made. 



A practical disadvantage of the French method is that the 

 numerous overtopped and intermediate trees left standing make 

 the execution of the thinning difficult. The felling of the trees 

 is often badly hampered, and considerable breakage of standing 

 trees occurs. Moreover, the piling and removal of the wood is 

 made more expensive by the many standing small trees. 



In actually carrying out a thinning in the field it is often 

 advantageous, and, in fact necessary, to secure the best results, 

 not to hold rigidly to a thinning of any given grade. For in- 

 stance, a Grade C thinning may be the kind desired, but where 

 dominant trees of a worthless species or diseased trees occur, 

 it is best to cut them, making in such places a heavier cutting. 

 The theory of thinnings as given here is exceedingly simple but 

 in application many problems will come up which cannot be 

 covered in the space of this discussion, and are best solved 

 through field experience. 



The lessening of the competition between the individual trees 

 which effects an increase in the rate of growth has already been 

 mentioned as the chief purpose of thinnings, but the results 

 which come through the aid of thinnings have not yet been fully 

 stated. 



The increase in rate of growth of the individual trees results 

 in obtaining trees of merchantable size several years sooner than 

 is possible in an un thinned stand. In other words, thinnings 

 enable the forester to shorten the rotation in which a given 



