^ BOARD MEASURE. 13 



In continental Europe and the Philippine Islands the cubic 

 meter has been established as the standard unit for measuring logs 

 and timber. 



BOARD MEASURE. 



Board measure is designed primarily for the measurement of 

 sawed lumber. The unit is the board foot, which is a board 1 

 inch thick and 1 foot square, so that with inch boards the content 

 in board measure is the same as the number of square feet of sur- 

 face; with lumber of other thicknesses the content is expressed 

 % in terms of inch boards. 



In recent years board measure has been used as a unit of volume 

 for logs. When so applied the measure does not show the entire 

 content of the log, but the quantity of lumber which, it is estimated, 

 may be manufactured from it. The number of board feet in any 

 given log is determined from a table that shows the estimated 

 number which can be taken out from logs of different diameters 

 and lengths. Such a table is called a log scale or log rule, and is 

 compiled by reducing the dimensions of perfect logs of different 

 sizes, to allow for waste in manufacture, and then calculating 

 the number of inch boards which remain. 



The amount of lumber which can be cut from logs of a given 

 size is not uniform, because the factors which determine the 

 amount of waste vary under different circumstances, such as the 

 thickness of the saw, the thickness of the boards, the width of 

 the smallest board which may be utilized, the skill of the sawyer, 

 ^ the efficiency of the machinery, the defects in the log, the amount 

 of taper, and the shrinkage. This lack of uniformity has led to 

 wide differences of opinion as to how log rules should be con- 

 structed. There have been many attempts to devise a log rule 

 which can be used as a standard, but none of them will meet all 

 conditions. The rules in existence have been so unsatisfactory that 

 constant attempts have been made to improve upon them. As a 

 result there are now actually in use in the United States 40 or 50 

 different log rules, whose results differ in some cases as much as 

 120 per cent for 20-inch to 30-inch logs and 600 per cent for 

 6-inch logs.ct Some of these are constructed from mathematical 



♦ a See Constantine and Cumberland River log rules in comparison table, 

 pp. 16-19. 



