Doyle Scale Calculator

The Doyle Scale is a log rule used to estimate the number of board feet in a log, primarily in North America. It’s one of the oldest and simplest formulas, widely used in the lumber industry.

Historical Background

The Doyle Scale was created by Edward Doyle in 1825 and became a standard method in forestry to estimate lumber yield from logs. The Doyle Rule tends to underestimate the yield for smaller logs due to its assumption of a fixed amount of wood lost to sawdust and other factors, making it less accurate than some other methods for smaller diameters.

Calculation Formula

The Doyle Scale formula is as follows:

\[ \text{Board Feet} = \frac{{(\text{Diameter} - 4)^2 \times \text{Length}}}{16} \]

Where:

• Diameter: The diameter of the log at its smallest end (in inches).
• Length: The length of the log (in feet).
• Board Feet: The estimated volume of lumber the log can produce.

Example Calculation

If a log has a diameter of 18 inches and is 16 feet long:

\[ \text{Board Feet} = \frac{{(18 - 4)^2 \times 16}}{16} = \frac{{14^2 \times 16}}{16} = \frac{196 \times 16}{16} = 196 \text{ board feet} \]

Importance and Usage Scenarios

The Doyle Scale is critical for loggers, foresters, and lumber mill operators to estimate the value and yield of logs before processing. It's commonly used for larger logs due to its simplicity but may underestimate yields for smaller ones. It helps in making purchasing decisions, negotiating prices, and managing forest resources.

Common FAQs

1. Why does the Doyle Scale underestimate smaller logs?

   • The Doyle Scale assumes a fixed deduction of 4 inches in diameter for sawdust and slab loss, which disproportionately impacts smaller logs, leading to underestimates.

2. Is the Doyle Scale still widely used?

   • Yes, despite being less accurate for small logs, it is still widely used in the lumber industry for its simplicity.

3. What are alternatives to the Doyle Scale?

   • The Scribner and International 1/4-inch scales are alternative methods that provide more accurate estimates, especially for smaller logs.

This calculator is an essential tool for anyone involved in timber measurement and lumber estimation, providing quick and simple calculations based on the Doyle Rule.