GROWTH. 



25 



the number and size of the knots decrease. Consequently, lumber sawed 

 from large trees is worth more per thousand feet than that from small 

 trees which are growing under the same conditions. 



Table 9 gives the per cent of the different grades of lumber sawed from 

 trees of yellow poplar of different diameters, using a circular saw which 

 takes l /\ -inch kerf and sawing the boards l*/s inches thick to allow for 

 shrinkage. This table, above a diameter of 12 inches, is derived from one 

 prepared by E. A. Braniff, showing the yield of trees of yellow poplar 

 when sawed with a band saw taking seven cuts to the inch. Mr. Braniff's 

 figures were obtained at a mill in eastern Tennessee. There is a constant 

 increase in the proportion as well as in the amount of the higher grades 

 with trees of a larger diameter and a corresponding decrease in the pro- 

 portion of the less valuable grades. 



TABLE 9. Percentage of different grades of lumber sawed out of yelloiv 

 poplar trees of different diameters. Diameters 13 inches and over, by 

 E. A. Braniff. 



