INTERIOR DEFECTS 



109 



is scaled at that point and its length judged by experience gained in 

 the locality by the butting off of defective logs; e.g., a log 20 inches in 

 diameter at the top end, 16 feet long, with a center rot measuring 3 inches 

 at top and 15 inches at butt, will lose the equivalent of a 15-inch butt rot, 

 and not a 3-inch piece. Should the log be 20 feet long, the average 



Fig. 15. — When the minimum length of board is 8 feet this log will scale one- 

 half of the contents of » 16-foot log. But with a minimum length board of 

 10 feet the log according to common practice will scale nothing and be culled. 



dimension of this rot, or 9 inches, would be taken, according to the 

 above arbitrary rule of scaling. But if the rot is present only in the 

 butt, the 15-inch measurement would apply to that portion of the log 

 which was judged to be affected, provided the length of the remaining 

 sound portion equaled the minimum length of board prescribed. 



Fig. 16. — Center rot extending through log. Effect of length of log in determining 

 the diameter of the portion to be culled. 



The scale of this log, if sound, would be 280 board feet, Scribner Decimal C 

 rule. The deduction for a rotten butt 15 inches in diameter and 16 feet long 

 is 228 board feet, residue 52 board feet or 18.2 per cent of sound scale.. The 

 log is a cull. The average w dth of rim left to be scaled after projecting the 

 area of the rotten butt upon the top end, is 2\ inches, or less than minimum 

 width of board, and not the actual measurement of sound wood at either the top 

 or the butt. 



If this log is 20 feet long, i.e., longer than a prescribed maximum length of 

 16 feet, the diameter of this rot is averaged at 9 inches. The 20-foot log, 20 inches 

 in diameter scales 350 board feet. The 9-inch measurement is applied to the 

 entire length of log, and the deduction is 111 board feet. The net scale is 240 

 board feet, or 68.6 per cent of total sound scale. Such a log is merchantable. 



