DBH stands for Diameter at Breast Height — the trunk diameter measured at 4.5 feet (1.37 m) above the ground. It is the standard reference point for tree measurement in North American forestry.

What is a 16-foot log section?

Sawlogs are commonly bucked into 16-foot lengths (sometimes 8 or 12 feet). Merchantable height divided by 16 gives the number of log sections. Enter 1 for trees with only a single log, 2 for two logs, etc.

Which log rule gives the most board feet?

The International 1/4" rule is generally the most accurate and produces the highest estimates. Scribner is intermediate. Doyle consistently under-estimates small-diameter logs (under 16") and over-estimates large ones (over 28"), so it often produces the lowest value for typical stands.

Are these estimates exact?

No — log rules are yield formulas, not measurements. Actual recoverable lumber depends on log taper, sweep, crook, rot, and mill efficiency. These estimates are a planning baseline, not a guarantee.

What species or region is this for?

Doyle, Scribner, and International 1/4" rules are unitless formulas applied to DBH and log length. They are used across North America regardless of species. Always confirm which rule is standard in your region or timber contract.

Can I use metric inputs?

This calculator uses inches and feet, which are the standard units for these log rules. To convert, multiply centimeters by 0.394 for inches and meters by 3.281 for feet.

Timber Yield Calculator

Name: Timber Yield Calculator
Availability: InStock
Author: Nham Vu

Enter tree diameter, merchantable height, and stand count to estimate total board-feet yield under Doyle, Scribner, and International 1/4" log rules.

Stand Parameters

Average DBH (inches) — diameter at breast height

16-ft Log Sections per Tree — merchantable height ÷ 16

Number of Trees in Stand

Log Rules to Display

Doyle Scribner International 1/4"

Enter stand parameters and click Calculate Yield to see results.

Board-Foot Yield by Log Rule

Per-log, per-tree, and stand totals

Log Rule	BF / Log	BF / Tree	Stand Total (BF)

Doyle: (D − 4)² × L / 16 — Simple; under-estimates small logs, over-estimates large ones.

Scribner: 0.79D² − 2D − 4, per 16-ft log — Tabular rule widely used in the US Pacific Northwest.

International 1/4": Iterative formula accounting for 1/4" saw-kerf taper — most accurate of the three.

BF = board feet. All estimates assume 16-ft log sections with 1" taper per 4-ft length (International rule only).

Summary