INTERMEDIATE CUTTINGS 83 



attaining the size possible if they had not been so seriously 

 hindered by the competition with neighboring trees. 



In order to prevent part of this competition and to keep the 

 leading trees in the stand growing at a rapid rate thinnings are 



Fig. 30. Plantation of white pine and European larch on first quality soil. The stand 

 has just received a C grade thinning. Total yield 40 cords per acre. Amount cut 

 16 cords per acre. Age 27 years. In the foreground most of the pine was removed, 

 leaving the larch. 



made. 1 Thinnings remove the trees which have fallen behind 

 the best trees of the stand but which still crowd them and ham- 

 per their development. 



It is convenient in discussing thinnings to divide the trees in a 

 stand into five classes, called crown classes, depending on the 

 relative position of each class with respect to the other trees in 

 the stand. 



1 The struggle for existence is best noticed in even-aged stands where trees of 

 the same age are competing. It is in such stands (even-aged) that thinnings are 

 particularly needed, although in forests of other forms there will be found small 

 even-aged groups here and there in which thinnings are useful. 



