10 STATE BOARD OF FORESTRY. 



the average dimensions of the lumber sawed. Large logs will generally 

 run higher than the intermediate sizes, due to the fact that the slab 

 allowance varies directly with the volume plus a constant. The follow 

 ing deduction shows the total waste allowance of the Spaulding Log 

 Rule expressed in per cent of the rule : 



(.048D 2 2)L = B. M. = total sawed out as shown by Spaulding 



Log Eule. 



7854Z) 2 



-L = total contents = .0655D 2 



1 L * 



.0655D 2 L (.048Z> 2 2)L = waste = [(.0655 .048 )D 2 + 2]L 

 = (.0175Z) 2 -f 



/ Qi75/) 2 [ 2) L 



100 -- = % waste based on total sawed out as shown 



by Spaulding Log Rule. 

 .0175Z) 2 -f- 2 



= 100 



When D = 10", the waste allowance based on the total sawed out 

 as shown by the Spaulding Log Rule = 134%. 



When D = 20", the waste allowance = 52.2%. 



When D = 30", the waste allowance = 43.1%. 



When Z> = 40", the waste allowance = 40.1%. 



When D = diameter in inches of very large logs, waste allow- 

 ance = 36.5%. 



The Scribner Log Rule. 



The Scribner Log Rule is the oldest rule in general use, and is the 

 statute rule of Idaho, Minnesota, Oregon, Wisconsin and West Virginia. 

 Also, it is the official rule adopted by the Federal Forest Service. 



It was constructed from diagrams the same as the Spaulding Log 

 Rule, and the following description was published by its author in 1846 : 

 "This table has been computed from accurately drawn diagrams 

 for each and every diameter of logs from twelve inches to forty- 

 four, and the exact width of each board taken after being squared 

 by taking off the wane edge and the contents reckoned up for every 

 log, so that it is mathematically certain that the true contents are 

 here given, and both buyer and seller of logs will unhesitatingly 

 adopt these tables as the standard for all future contracts in the 

 purchase of saw logs where strict honesty between party and party 

 is taken into account. In these revised computations I have allowed 

 a thicker slab to be taken from the larger class of logs than in the 

 former edition, which accounts for the discrepancy between the 

 results given in these tables and those in former editions. 



"The diameter is supposed to be taken at the small end, inside 

 the bark, and in sections of 15', and the fractions of an inch not 

 taken into the measurement. This mode of measurement, which is 

 customary, gives the buyer the advantage of the swell of the log, 

 the gain by sawing into scantling, or large timber, and the frac- 

 tional part of an inch in the diameter. Still it must be remem- 

 bered that logs are never straight and that oftentimes there are 

 concealed defects which must be taken as an offset for the gain 

 above mentioned. It has been my desire to furnish those who deal 



