Estimate Doyle-scale board feet from the small-end diameter inside bark and log length.
Doyle scale estimate
This is a log-rule board-foot estimate, not geometric cubic volume or guaranteed mill recovery.
Doyle formula
Board feet = (D − 4)² × L ÷ 16, where D is the small-end diameter inside bark in inches and L is log length in feet. Values below a 4-inch inside-bark diameter return zero.
How to measure
Measure the average diameter across the small end after excluding bark. Use the merchantable log length, not the full standing-tree height.
Scale limitation
Doyle is a log rule that estimates board-foot yield with built-in assumptions about slab, kerf and processing loss. It is not geometric volume and does not guarantee actual lumber recovery, grade or sale value. Confirm the buyer’s required rule and deductions.
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