18 CHESTNUT IN TENNESSEE. 



dur'ng the first few decades, can be thinned earlier than seedling 

 stands. The interval between thinnings should vary from five to 

 ten years, depending upon the rate of growth of the trees and the 

 rap:'dity with which the crown cover becomes filled. As a rule, fre- 

 quent light thinnings give better results than heavy ones at long 

 intervals. Trees should be removed evenly through the stand, and 

 large clusters of sprouts should be well thinned. By repeating the 

 thinnings it is possible to maintain ^practically the same rate of 

 diameter increase for a long period and to prevent the progressive 

 decline which takes place in close, unthinned stands. (Table 2). 



Thinnings are seldom profitable unless the wood that is removed 

 can be used, or can be sold for enough to coyer the cost. Early 

 thinnings will yield only small wood suitable for fence post's or 

 cordwood. Later thinnings will yield some ties and poles, partic- 

 ularly when the stand is being held for large sized sawtimber. 



In order to cut trees to best advantage into hewn ties or into 

 poles, it is necessary to maintain sufficient crowding to prevent the 

 stems from being too tapering and to cut before the butts become 

 too large. In the production of sawtimber it is desirable to obtain 

 the largest diameters. For this reason thinnings to accelerate 

 diameter growth become of even greater importance in providing 

 sawtimber than in stands intended for poles and hewn ties. Thin- 

 nings should begin earlier and should be heavier than in stands 

 managed for ties and poles. 



It is often advisable to thin the sprouts around large stumps. 

 This can be done during the first winter by breaking off the smaller 

 ones, and leaving vigorous sprouts about one foot apart around the 

 stump. 



Comparative Yield of Thinned and Unthinned Stands A com- 

 parison of the thinned and unthinned plots in Table 3 shows the 

 actual results in increasing the merchantable volume of stands even 

 by a thinning which was unsystematic. Had the thinning been 

 systematic, the yield would undoubtedly have been higher, and if 

 these two thinned stands had been removed in two cuttings/ made 

 at intervals of from 10 to 15 years, it is probable that their yield 

 could have been increased to 25,000 board feet, or that more than 

 700 sawed ties 7x7 inches and 8 feet long could have been obtained 

 per acre. 



