56 



STATE BOARD OF FORESTRY. 



A volume table based on the above rule with a taper allowance of 

 1/2" in 8' should be compiled as follows : 



Values for 8' sections of different diameters are first determined 

 directly from the formula. Then 16' logs are considered as being made 

 up of two 8' sections, the one being one-half inch in diameter greater 

 than the other; 24' logs as three 8' sections, one of them being the 

 measured diameter at small end of log, another one, one-half inch greater 

 than this, and the third, one inch greater. Thus, 26 board feet, which 

 / is the volume given in the above table for a log 16' long and 6" in 

 diameter, was obtained by adding 12 board feet, which is the volume 

 given for an 8' section of same diameter, and 14 board feet obtained by 

 averaging twelve and sixteen. (The average of 12 and 16 board feet 

 gives volume for 8' section, six and one-half inches in diameter.) The 

 volume of the 24' log of six inches in diameter shown in the table was 

 obtained by adding 26 and 16. Twenty-six board feet being the volume 

 of the first two 8' sections contained in the log and sixteen board feet 

 being the volume of the third or largest section. Other values may be 

 obtained in a similar manner. 



If the taper allowance were 1" in 8' instead of 1/2" in 8', a 16' log 

 6" in diameter at the small end would scale the same as two 8' sections ; 

 the one 6" in diameter and the other 7". A 24' log 20" in diameter 

 would, in like manner, scale the same as three 8' sections ; the first 20", 

 the second 21" and the third 22" in diameter. If this log were 22' 

 long instead of 24' the scale would then be equal to that of the first two 

 sections plus three-quarters of the third. By similar computations, all 

 values composing a complete volume table for logs of different diameters 

 and lengths can be compiled. 



Log rules determined as explained in this Appendix apply to average 

 conditions existing at the mills where they are made and are average 

 rules which do not measure the fluctuations encountered in individual 

 logs. 



