118 THE SCALING OF DEFECTIVE LOGS 



that the scale should not vary from the check scale by more than the following 

 per cents: 



For sound logs, within 1 per cent; 

 For logs up to 10 per cent defective, within 2 per Cent; 

 On logs 11 to 20 per cent defective, within 3 per cent; 

 On logs over 20 per cent defective, within 5 per cent. 



Check scales are made usually for the purpose of correcting the scaler, but not 

 as a basis of altering the scale. Only where the original scale is shown to be 

 decidedly in error so as to work an injustice on the purchaser (or seller) are logs 

 ever re- scaled. 



Personnel. Scalers should never be reprimanded in general terms for scaling 

 too close or too high. The result is usually a worse error in the opposite direction. 

 Instead, the scale should be checked by individual logs to discover the sources of 

 error and the scaling practice corrected in detail. The fault may lie in some 

 specific practice such as an erroneous method of obtaining diameters or in allowing 

 for certain, common defects. 



Mill-scale studies do not furnish an adequate or satisfactory check 

 on scaling, but serve merely to determine the over-run. The scale, 

 if in error, must be corrected by re-scaling the logs, not by measuring 

 the lumber (§ 74). Such studies do furnish an indication of the scale 

 of defective logs, where the scaler's judgment may be in error, but an 

 exact check is impossible, as it would require the rejection of boards 

 sawed from the taper, which is not practicable. 



95. Scaling from the Stump. Where timber has been cut in tres- 

 pass and the logs removed, the evidence remaining is the stump, the 

 indentation on the ground where the butt struck in falling, the sawdust 

 where the cuts were made in sawing into log lengths, and the top, 

 giving the upper diameter. The length of the tree can then be meas- 

 ured, and occasionally, that of each log sawed. The total difference 

 in diameter between top and butt is distributed according to the accepted 

 local customs for scaling long logs. This gives the scaling diameter 

 and length of each log in the tree. Specific deduction for defect can 

 be made only for stump rot, since this is revealed by the stump and 

 the average deduction for rot having the character and extent of that 

 shown can be made from the butt log. Further deductions if made 

 must be based on the average per cent of cull for timber of the given 

 species and character. 



When tops are removed, burned or otherwise rendered indistinguish- 

 able, neither the top diameter nor the length of the tree can be judged. 

 Merchantable length must then be based upon the heights of trees in 

 the vicinity, and volumes taken from volume tables (§ 121) for trees 

 of given diameter and height. A table of stump tapers (§ 168) must 

 be used to express the diameter of the stump in terms of diameter 4| 

 feet from ground (§ 134). 



