INCREASING THE YIELD. 



43 



Table 15 shows the most profitable diameters and ages at which to cut 

 stands of second growth yellow poplar which have been established with- 

 out cost and which are unthinned, cutting to different diameters. When 

 the current rate per cent, of increase in value falls below 6 per cent, the 

 stand can be considered as mature. It should be noted that price increment 

 is neglected. 



TABLE 15. Yellow Poplar. Period of maturity of natural unthinned 

 second-grozvth stands for saw-timber. Average conditions of growth. 

 Price increment neglected. 



Cutting to 7 inches 

 breast-high 



Age 



of 



stand 



Years 



20 

 25 

 30 

 35 

 40 

 45 

 50 

 55 

 60 

 65 



Average 

 diameter 



breast - 



high of 



trees in 



stand 

 Inches 



4.9 



5.9 



6.8 



7.6 



8.3 



9.0 



9.5 

 10.0 

 10.4 

 10.8 



Value of 



stand 

 per acre 

 saw- 

 timber 

 only 



$ 17 



29 



43 



60 



78 



97 

 114 

 130 

 143 

 154 



Average Current 



annual rate of 



increase increase 



in value in value 



$0.85 

 1.16 

 1.43 

 1.71 

 1.95 

 2.16 

 2.28 

 2.36 

 2.38 

 2.37 



Per cent. 

 23.0 

 11.0 

 8.0 

 7.0 

 5.0 

 4.5 

 3.3 

 2.7 

 2.0 

 1.5 



