Doyle log rule
The Doyle Log Rule is used in East and Central parts of North America. It originates from 1825. Different to the Scribner rule, Doyle is based on a formula.
bf volume = (small-end diameter in inches – 4)² x length /16
bf means board foot which in principle represents a piece of wood which is nominally 1 ft x 1 ft x 1 in. In actuality it represents volumes and/or dimensions that are significantly different depending on the product being reflected, e.g. logs, lumber, (type of lumber, size of lumber).