THE CUBIC FOOT A3 A NATIONAL LOG-SCALING STANDARD"^ 



By 



E, F. Eapraeger 



INTRODUCTION 



That board-foot log rules inadequately serve their purpose in determining 

 the quantitative contents of logs has been recognized to a greater or lesser 

 extent ever since the first rule came into being over a c entry ago. Whoever 

 invented the second rule probably did so because the first was in disrepute 

 or was not widely accepted* But providing a log rule which xrould be widely 

 used proved to be no easy task* Apparently there were many diverging 

 opinions pertaining to log rules,, for in succeeding years forty or fifty 

 more were devised, old ones were remodeled,, and hybrid rules were con- 

 structed by combining the best or worst features of existing rales. Since 

 the number of rules and their inconsistencies led to endless confusion, 

 many were discarded and passed into oblivion* Not more than a dozen are 

 still in wide commercial use* Using these has now become a custom, albeit 

 often a bad one* 



Undoubtedly most makers of board-foot log rules intended them to show with 

 a reasonable degree of accuracy the number of board feet of lumber that 

 could be obtained from logs of different sizes* These estimates were called 

 "board feet log scale *" Though the similarity in name creates an impression 

 that board feet log scale and board feet of lumber are identical, actually 

 there are decided differences * 



A board foot of lumber is a piece 1 foot wide, 1 foot long, and 1 inch thick* 

 Equal in volume to one twelfth of a cubic foot, it makes an exceedingly con- 

 venient unit for measuring the volume of boards » Lumbermen have used this 

 standard for years and found it satisfactory It should not be inferred 

 from anything said herein that a new standard is advocated for measuring 

 lumber a 



Unlike a board foot of lumber, hovrever, the board foot log scale is an 

 ambiguous unit of no certain sizes Sawmill men have learned that the board- 

 foot scale of a run of logs is apt to be merely a rough criterion of the 

 yield of lumber,, There is usually some disparity between the log scale and 

 the lumber tally, the amount depending on the size of the logs, the log rule 

 used, who saws the logs and how, and various other factors* If the yield of 

 lumber exceeds the log scale, the excess is called overrun* If a shortage 

 occurs, it is called under run The amount of the overrun or under run cannot 

 be foretold unless similar logs have been sawed in the same mill* 



Many manufactories which produce products other than lumber (pulp, veneer, etc*) 

 have also learned from experience that the board foot log scale is ambiguous* 

 They find that the relationship between a log's size (cubic volume) and its 



1/ This Paper was originally published January 31, 1940 as an unnumbered 

 mimeographed release of the Northern Rocky Mountain Forest and Range 

 Experiment Station 



