Request a Quote Softwood Cedar Fir Hemlock Pine Redwood Spruce Other species available upon request. GoodWOOD offers Saw Logs and Veneer Logs. Hardwood logs we offer include, Ash, Beech, Birch, Cherry, Hard and Soft Maple, Hickory, Red and White Oak and Walnut. Other species are available upon request. We offer the following Softwood Logs: Fir, Hemlock, Pine, Spruce, and other species are available upon request. Logs may be graded, which is a quality measure, not volume measure. Measuring Logs and Lumber by Professor Gene Wengert. How much wood can a woodchuck chuck...? Logs are really truncated cones. Lumber is, however, a rectangular parallelepiped. When measuring logs, the real question is “How many rectangular parallelepiped fit in a truncated cone?” If you know the answer, then you know how many board feet of lumber a log contains and can begin to determine the log’s value. IMPORTANT NOTE: Scaling measures volume; grading determines quality. Scaling and grading are different operations.

Request a Quote HARDWOOD Ash Bass wood Beech Birch Cherry Hard Maple Hickory Soft Maple Red Oak White Oak Walnut Other species available upon request.

One way to answer the question raised is to draw a circle, representing the small end of a log. Then, if I assume that the log doesn’t curve or bend, I can easily draw a bunch of rectangles inside the circle, representing the ends of pieces of lumber, to get the board footage. Of course, I better include a space between each rectangle to represent the sawdust. Another way to determine the answer would be to get a bunch of logs that are all the same size (as close as possible) and then saw these logs into lumber and measure the output. Using a log rule All the major log rules use the small end diameter, inside the bark, as the basic size measurement; this diameter is called the Scaling diameter. If the log is not perfectly round, then two readings are taken at 90 degrees to each other and averaged. Many rules will stipulate that the diameters are measured to the closest inch, and if the average of two diameters is exactly on the half, round up once and then round down the next time. In any case, the diameter measurements are supposed to represent a cone; butt swell, dipsy-doodles, or other small weird protuberances or depressions would be ignored. The log length is the length to the last full foot (especially for hardwood logs); do not round up to the next foot. Softwoods are often measured to the last full even foot (i.e., 8, 10, 12, etc.). Hardwoods used to be measured to the even foot, but not so much anymore. What about log defects, like a squirrel hole, fire scar, forks, or …? The person measuring the log, often called a scaler, may decide that the last two feet of a log is not useful and will then scale the log as being 10 feet long instead of 12 feet actually measured. Or if there is a bad defect on one side, the scaled footage can be reduced proportionately. For gentle sweep (or crook), there are tables that indicate how much to deduct from the scaled answer. In most cases, the footage numbers are given to the closest 10 BF (sometimes to the closest 5 BF; very seldom would the footage be more precise). Because all the numbers then will end in zero, the results are sometimes given without the zeros-­for example, 240 BF is given as 24. With such a procedure, the log rule will have the word “decimal” added to it.

Make it simple ?

There are some people who believe that such a complicated scaling system for logs should be made easier. The way to do that is to measure the diameter at both ends of the log and also the actual length. Then, using the basic formula for volume of a cone (7th grade geometry class?), then we could figure out the cubic footage-oops, I mean cubic meters. In fact, the U.S. Forest Service now requires timber sales to be in cubic metric values. Of course, conversion between the "old" system and metric system is nearly impossible, unless you know diameters, log rules, etc. In other words, 10,000 cubic meters of pulpwood logs will have very little board footage compared to 10,000 cubic meters of 20" diameter and larger logs.

There are three ways to get the actual footage number:

1. Tables:
The footage values have been tabulated for the three rules for different diameters and lengths. Simply, look up the numbers. (A few sample numbers are given in Table 1.

2. Formula:
A second method is to use a formula that represents the log rule; often one rule may have several slightly different formulas. These formulas use diameter (D) and length (L) with volume (V) in board feet.

Doyle is V = [L x (D - 4) x (D - 4)] / 16

Doyle is also V = [0.0625 x D x D x L] [0.500 x D x L] + [1.000 x L]

Scribner is V = (0.0494 x D x D x L) - (0.124 x D x L) - (0.269 x L)

International is V = 0.905 x ([0.22 x D x D] - [0.71 x D]) for every 4 foot length of log.

3. Scaling Stick:
A third method, and the most common, is to use a scaling stick. This is a piece of wood (about 1/4 inch thick and 1-1/2 inches wide) that has the footage numbers printed on the stick. The numbers are located on the stick at the spot that represents the diameter for that number. (For example, a 16" diameter log that is 16 feet long scales as 360 BF; the number 360 will be located 16 inches from the end of the stick.) There will be several sets of numbers representing different log lengths. The stick is held up to the end of the log (running across the log measuring the diameter) with one end of the stick at the edge of the bark and wood. Where the bark and wood cross the other end of the stick, the appropriate number scale is read to determine the footage. (Here is how I measure oval logs with a scaling stick: The diameter is measured at the largest spot and then I mark this measurement on my stick holding my fingernail at the correct spot. Then I move the stick to measure at 90 degrees and note the second (and smaller) diameter reading. I then move my fingernail to a spot halfway between the first and second readings and use that spot for getting the footage value).

Log Scale Rules

Instructions: Log Volume Calculator

Diameter:
All the major log rules use the small end diameter, inside the bark, as the basic size measurement. If the log is not perfectly round, then two readings are taken at 90 degrees to each other and averaged.

Length:
The log length is the length to the last full foot (especially for hardwood logs). Do not round up to the next foot. Any inches entered will not be considered in the calculation. Softwoods are often measured to the last full even foot (i.e., 8, 10, 12, etc.).

Number of Logs:
Enter whole number values (no decimals or fractions)

Log Scale:
You must choose one of the three log scales listed. For more on log scales, see notes below.

Log Volume
There are three major methods used to calculate volume:

Doyle Log Rule:
The Doyle Log Rule, developed around 1825, is based on a mathematical formula and is widely used. This rule allows for a saw kerf of 5/16 inch and a slabbing allowance of 4 inches, which is about twice the normal amount. Because of this, the Doyle Rule is somewhat inconsistent; it underestimates small logs and overestimates large logs. As a seller of timber, you must be aware that for smaller logs the Doyle Rule will underestimate the actual volume of wood that you have in your trees.

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Scribner Log Rule

The Scribner Log Rule, developed around 1846, is a good example of a diagram rule. It was created by drawing the cross-sections of 1-inch boards within circles representing the end view of logs. A space of 1/4 inch was left between the boards to account for saw kerf. The Scribner Rule does not have an allowance for log taper and typically underestimates logs, particularly if the log length is long. The Scribner Decimal C is a different form of the Scribner Rule; it rounds the volumes to the nearest 10 board feet. For example, 392 board feet on the Scribner is equivalent to 390 board feet on the Scribner Decimal C scale.

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International 1/4-Inch Log Rule

This rule was developed in 1906 and is based on a reasonably accurate mathematical formula. The rule allows for a 1/4-inch saw kerf and a fixed taper allowance of 1/2 inch per 4 feet of log length. Deductions are also allowed for shrinkage of boards and a slab thickness that varies with the log diameter. Overall, the International 1/4-Inch Log Rule is the most consistent and is often used as a basis of comparison for log rules.

A selection of scaling values for Scribner, Doyle and International 1/4-Inch Rule for a 12 foot straight log.