l88 INTERMEDIATE CUTTINGS— THINNINGS 



Where a large percentage of clear lumber is desired the 

 stand must be kept fairly dense, and moderate thinnings 

 will be in order. If large volume production is wanted with- 

 out a product of high technical quality, then thinnings at 

 least as heavy as Grade C under the ordinary system prove 

 the best. WTiere lumber of wide dimension is demanded, 

 even if somewhat knotty, very heavy thinnings can be made. 



Shade enduring trees can grow thriftily with less Hght than 

 the light demanding species and do not receive such heavy 

 thinnings as the latter. 



The German and French methods will be used oftener than 

 Borggreve's. One thinning under the latter method and then 

 reversion to one of the other methods may meet the situation 

 in many somewhat irregular stands, previously unthinned, 

 and in localities where to-day only the bigger trees afe saleable. 

 Between the German and the French methods the choice. is 

 difl&cult and may be decided by existing market conditions in 

 favor of the French idea. 



The ordinary method in its lower grades A and B does 

 little more than utilize trees which would otherwise be wasted. 

 The growth of the stand cannot be stimulated by removing 

 only those trees which already are conquered in the struggle 

 for existence. Grades C and D are needed to secure this 

 result, and are the grades advised in most cases when the 

 ordinary method is employed. 



Use of all three methods combined in the same stand to fit 

 variation in conditions encountered is often the wisest course. 



Thinnings can well be increased in severity with advancing 

 age in order to satisfy the demands of the trees for more Kght 

 and room. Indeed, due to the larger crown spread of the 

 individual trees in an older stand, bigger gaps must be left 

 if any thinning is made. 



In applpng thinnings the danger from windthrow and 



