Formula Rules 



Formula rules are based on a mathematical statement -which gives the 

 board-foot contents after making allowance for waste and other elements 

 influencing lumber yields One of the poorest rules of this type is the 

 Doyle, Though the Doyle is used extensively, it is reputed to be one of 

 the most inconsistent rules ever devised <> 



One of the better rules which is based on a formula is the International <» 

 Embodied in it are allowances for log taper ? saw kerf , slabs, edgings, 

 and lumber shrinkage « There is no doubt that the International is better 

 adapted to accurate work than most of the other log rules now in existence 

 Unfortunately it is seldom used commercially except in the Hew England 

 States s where it recently found favor a In most sawmills, logs measured 

 with the International will under-run the scale. There is a tendency for 

 small logs to give overruns* 



Those who wish to learn more about log rules and their construction will 

 find considerable information in various textbooks on forest mensuration 

 Table 1 is also of assistance as it makes comparisons among a few of the 

 best known log rules » 



THE NEED F OR A GOHLION STANDARD 



The timber industry, one of the largest in the nation with billions of 

 dollars in investments, needs a common standard for figuring log volumes 

 and for buying and selling timber Log rules have flourished for a 

 century but no standard has so far been evolved. It is probably true 

 that this is the fault of the board foot log scale * It is so ambiguous 

 and so indefinite that it fails to meet the requirements for a standard 

 which can be used in common by sawmills 3 pulp mills, and other users of 

 timber o Changing from one log rule to another seems to be merely a 

 matter of jumping from the frying pan into the fire, or back again* 



The United States has many units of measure,, among which are units of 

 weight (ounce s g^^s pound? ton), units of length (foot, mile, centimeter), 

 and units of volume (cubic foot, gallon, board foot of lumber), to mention 

 only a few„ The board foot log scale differs from all these standards in 

 three important respects: 



lc There are as many definitions of a board foot 

 log scale as there are log rules and log sizes « 



2, No single log rule has ever been nationally 

 accepted as a common standard* 



3s Log rules which are accepted as standards in 

 limited areas are replaced from time to time by 

 other log rules* 



The basic assumption that a board foot log scale is approximately equal 

 to a board foot of lumber creates innumerable difficulties and results in 

 a multiplicity of log rules* Log rules are used today that did not exist 

 50 years ago* Rules 9 old and new, fall into disrepute and are replaced 



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