1. What is the Doyle Log Rule?

The Doyle Log Rule is a formula used to estimate the amount of lumber that can be sawn from a log. It's one of several log rules used in the forestry and lumber industry, though it tends to underestimate volume, especially for smaller logs.

2. How Does the Calculator Work?

The calculator uses the Doyle rule formula:

Where:

• \( D \) — Diameter of the log inside bark at small end (inches)
• \( L \) — Length of the log (feet)

Explanation: The formula accounts for the taper of the log and sawing losses. The subtraction of 4 inches accounts for slab loss when squaring the log.

3. Importance of Board Foot Calculation

Details: Accurate board foot calculation is essential for log buyers and sellers to determine fair pricing, for sawmills to estimate production, and for foresters to assess timber value.

4. Using the Calculator

Tips: Measure the diameter at the small end of the log (inside bark). Enter diameter in inches and length in feet. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why subtract 4 inches in the Doyle rule?
A: This accounts for the slab (outer portion) that's lost when squaring the log for lumber, plus saw kerf (the width of the saw blade).

Q2: How accurate is the Doyle rule?
A: Doyle tends to underestimate volume, especially for smaller logs (<16 inches). It's more accurate for logs 28+ inches in diameter.

Q3: Are there other log rules?
A: Yes, common alternatives include Scribner (simpler but less accurate) and International 1/4" rule (more accurate but more complex).

Q4: What's considered a good log for lumber?
A: Generally, straight logs with minimal taper, few knots, and diameters 12+ inches are preferred. Length is typically 8-16 feet.

Q5: Does this account for log defects?
A: No, the Doyle rule gives theoretical volume. Actual recoverable lumber may be less due to knots, rot, or other defects.