146 



ELEMENTARY FORESTRY. 



The Number of Feet B. M. which May be Obtained 

 from a I/og varies with the management of the cutting, the 

 width of kerf, the width of boards, whether one or two inch 

 boards, or some of both are cut from the same log. Usually the 

 cut exceeds the scale. Take, for example, a log sixteen inches in 

 diameter at the small end, eighteen inches at the middle, twenty 

 inches at the large end, and twelve feet long. Such a log con- 

 tains about 21.2 cubic feet. The official scale gives 119 feet B. 

 M., which is equal to 9.9 cubic feet. The actual cut should give 

 155-75 ^et B. M., or thirteen cubic feet of lumber, the slab would 

 be about 5.3 cubic feet, and the kerf (sawdust) about 2.9 cubic 

 feet. From this it would appear that the Minnesota official scale 

 gives the seller 46.7 per cent of his log, while the mill turns out 

 61.3 per cent in lumber, 13.7 per cent in sawdust and 25 per 

 cent in slab. The producer loses 53.3 per cent of the scaled log; 

 but that is not all his loss. In marking logs to be cut the under- 

 cutter allows at least three inches over the required length to 

 cover loss in checking; that is, a log scaled at twelve foot length 

 would really measure twelve feet and three inches, or more. 



The Percentage of the I/ogs.on which the seller or pro- 

 ducer gets returns varies with different sizes and shapes. The 

 following table will serve as a comparison: 



