The Ontario Log Rule is a method used in the forest industry to measure the volume of a log in board feet. It applies to logs with diameters from 4" to 40" (measured small end, inside bark) and lengths of the log from 8' to 18'.
Board feet = (0.55D² - 1.2D) * L ÷ 12 D = diameter small end inside bark in inches L = length of log measured in feet
Log lengths are measured in full feet.
Small end diameters of the log are measured inside the bark and recorded in one-inch diameter classes and rounded off to the nearest inch