17 



VOLUME IN BOARD FEET (SCR1BXER LOG RULE). 



Each of the three general regions is represented by a volume table 

 in board feet, to which is attached the top diameter cutting limit. 

 The Black Hills region gives the largest volumes, with Arizona next, 

 and California the smallest. Further, the utilization in the tops is closest 

 in the Black Hills, Arizona next, and California least close. This is, 

 t.) some extent, due to the form of the tree and to the difference of 

 value of the poorer top logs in the different regions. However, this 

 difference in utilization can account for only a part of the variation 

 in volume, as shown by a comparison of the tables giving the volume 

 of entire stem for California and the Black Hills. 



Tables 14, 15, and 16 give, respectively, the board-foot contents 

 for the three general regions. The Black Hills and the Arizona 

 tables show volumes approaching each other rather closely, which is 

 accounted for by the similarity in conditions in those regions. Cali- 

 fornia, however, shows much smaller volumes. The smaller volume 

 for California is best explained by the form tables on pages 22 and 23. 



The tables were made up by scaling logs as cut by lumbermen. 

 The logs varied in length from 10 to 18 feet. The larger part of the 

 California trees were cut into 10-foot logs, and for that reason every 

 advantage of taper gained by scaling short logs must be credited to 

 the California table. The Black Hills table shows diameters down 

 to 8 inches, since the smaller trees are merchantable there. 



Trees much larger than 48 inches are found in California, but there 

 were not sufficient data available for an extension of the table be}^ond 

 that diameter. However, a fairly accurate estimate can be made by 

 finding the volume of half the diameter, under the required height 

 class, and multiplying by 4, since with equal heights the volumes 

 vary as the squares of the diameters. As an illustration, in Table 

 16 a 24-inch, 150-foot tree contains 1,040 board feet; by the sug- 

 gested method, a 48-inch tree, 150 feet high, should have 4 X 1,040, 

 or 4,160 board feet. In the table it is given as 4,250. According 

 to the table a 33-inch tree, 170 feet high, contains 2,330 board feet; 

 a 66-inch tree of the same height should contain about 9,320 board 

 feet. The volumes given for the larger diameters are conservative. 



The relation between the Scribner scale and actual saw cut 

 can not be given at this time. It varies with different saws, dif- 

 ferent log diameters, with the efficiency of the sawyers, and, most 

 of all, with the kind of log. Rapidly tapering logs will give a larger 

 overrun than cylindrical logs. 



[Cir. 127] 



