158 INTERMEDIATE CUTTINGS THINNINGS 



The larger diameters, and hence widths of lumber, obtain- 

 able from thinned stands heighten the value of the product. 

 Greater crown development following the opening up of the 

 stand by a thinning does not reduce the clear length of the 

 trees. In fact although the crown may be lengthened by 

 thinnings yet greater clear lengths may be produced on account 

 of the greater total height in the thinned stand. 1 



3. By thinnings the total yield both in quantity and in value 

 of product secured from a given area in a specified period will 

 be increased. Various factors contribute to this result. 



Thinnings remove and utilize principally trees which in the 

 unthinned stand die in the struggle for existence and decay 

 before the crop is harvested. As thinnings can be applied 

 so as to increase the total quantity secured from thinnings 

 and reproduction cuttings combined during a given period 

 from 50 to 100 per cent above the final yield of an unthinned 

 stand the saving in amount of product is considerable. 



The yield is increased in value for the reasons: 



First, a higher quality of product is produced as explained 

 under heading 2. 



Second, the thinnings furnish financial returns compara- 

 tively early in the rotation. With a timber crop which re- 

 quires a long time to mature the time element involving com- 

 pound interest charges is a vital factor in determining costs 

 of product on. Early returns mean higher profits. 



Third, the shorter rotation within which the same sized 

 products can be grown as on a longer rotation in the unthinned 

 stand has a favorable influence on the financial result similar 

 to that exerted by the early returns from the thinnings. 



4. Stands may be made more resistant to windthrow and 

 breakage by ice, snow and wind if thinned. The expansion 

 of the crown and root system following a thinning increases 

 the power of a tree to withstand these agencies. A slender 



