38 STATE BOARD OF FORESTRY. 



MISCELLANEOUS LOG RULES. 



The Chapin, Northwestern, White and Ballon log rules have no 

 definite underlying principles. 



The Drew and the Forty-five were found to be of the form 



= B.M. 



4X 12 



Where c = constant less than 1 and greater than 0. 



Where e = constant much smaller than c and greater than 0. 



Their formulae are as follows : 



The Forty-five rule : 



1 1 (.496 .00763 D)\ ~L = B.M. 



L J 4 X 12 



The Drew Rule : 



-(.450 .OOSDjl n -^L = 



In these rules the allowance for total wastage when expressed in per 

 cent of the total contents of the log, taper not considered, decreases uni- 

 formly as the diameter increases. When eD = c, there is no allowance 

 for wastage whatever. The Forty-five Log Rule allows for no wastage 

 in logs 65" in diameter and shows more volume for logs over 65" than 

 they actually contain. The Drew rule also shows a uniformly decreas- 

 ing per cent of wastage, and for logs 150" in diameter the waste allow- 

 ance becomes zero. The principle of these rules is absolutely incorrect. 



