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!fnopEf?rv OF* H\ DIVISION or 



FORESTRY 



OF fc AGRICULTURE 

 OF CALIFORNIA 



DISCUSSION OF LOG RULES 



INTRODUCTION 



IT is customary among the lumbermen of this country, when buying or 

 selling logs, to base their calculations upon the value of the lumber 

 the logs will produce when sawed rather than upon the total volume. The 

 by-products, such as slabs, sawdust, and loss by normal crook, which 

 accompany the manufacture of lumber from logs of various sizes, are 

 therefore ignored in the valuation, and tables have been compiled which 

 aim to show the volume of lumber in units, known as board feet 

 (l"x 12"x 12"), after the elimination of by-products has been made. 

 Such tables are called "log rules.'' 



It is the object of this publication to discuss many of the different log 

 rules now in use, to show the principles upon which they are based, and 

 wherein they are defective ; to introduce a new log rule, based upon 

 mathematical principles, and designed to be flexible to the varying con- 

 ditions, both in milling operations and in the^ch'aracter of the timber to 

 be sawed. Also, to show relations, where they exist, between any two 

 rules or any number of rules, such that a transformation from one rule 

 to another can be accomplished, and to reduce the various rules, wher- 

 ever possible, to a definite form, in order that comparisons by formula 

 may be easily made, and the allowance for slabs, sawdust, etc., by each 

 rule readily ascertained. 



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