92 LOG SCALING FOR BOARD MEASURE 



logs whose length exceeds a given maximum are scaled as two or more 

 sections or shorter logs (§• 43). Custom or " scale " determines the 

 maximum length to be scaled as one section and the method of deter- 

 mining the taper or diameter of the second or remaining sections to be 

 scaled. Short sections scaled to full or actual top diameter give the 

 maximum scale, while the loss from scaling long logs as one piece based 

 on diameter at top end may be very large, due to the increasing per cent 

 of volume in long logs which lies outside the cylinder and is thrown into 

 the over-run. 



The standard lengths of softwood or coniferous logs are multiples of 

 2 feet, to which is added an allowance for trimming. Where long logs 

 are divided into two or more lengths for scaling, this rule is still adhered 

 to; e.g., a 26-foot log is scaled as a 14- and a 12-foot. Usually the 

 longer length is scaled as the butt log. 



The tremendous variations in scale which may result from different 

 treatment of scaling lengths and taper in long logs is illustrated in Table 

 V (§ 44). In order to secure a consistent scale between long and short 

 logs, the scaling length should be limited to not over 16 feet, and the 

 actual diameter of each section taken as the scaling diameter. 



Trimming Allowance. The trimming allowance varies according to the method 

 of transportation used. For logs hauled by rail or driven down sluggish streams, 

 from 2 to 3 inches is allowed for each 16 feet of length. Large logs require the 

 greater allowance, to guard against slanting cross cuts which might give a short 

 length on one side. Where logs are driven down swift rocky streams the trimming 

 length must be sufficient to allow for the brooming of the ends. In very bad waters, 

 the exact length of a log is immaterial and the loss from brooming a heavy item. 

 Odd lengths, i.e., lengths measured in odd feet as 13 feet, are permitted in hard- 

 woods and to a limited extent in softwoods. 



In ordinary scaling, trimming lengths in excess of standard 2-foot gradations 

 are not scaled. But sellers of logs, to reduce loss from careless cutting of log lengths, 

 may stipulate that when trimming lengths are in excess of the margin agreed 

 upon, the log shall be scaled as if cut from 1 to 2 feet longer. The U. S. Forest 

 Service adopts this practice as a penalty scale. 



Scaling Diameters. In the apparently simple process of measuring 

 the diameter inside the bark at the top end of the log, there are two ways 

 in which the buyer may be given the advantage of a smaller scale. Owing 

 to the irregular cross sections of logs, an average diameter should be 

 found by taking two measurements at right angles. Instead, the 

 practice of scaling the smallest diameter is common. The difference, 

 in large logs, sometimes amounts to 2 or 3 inches. The second choice 

 lies in the treatment of fractional inches. These fractions should be 

 rounded off to the nearest inch; e.g., the 18-inch log class should include 

 diameters from 17.6 inches to 18.5 inches. Instead; all fractions may 



