Determining the amount of usable lumber in a tree is a key concern prior to any timber removal. If there is a specific project calling for a certain amount of wood, you'll need to know how many trees to remove. Even if you are simply removing a single tree, it's helpful to have an estimate of its yield. In the United States, it is common to measure lumber in board feet, defined as 144 cubic inches of wood, usually involving a piece of wood 12" long, 12" wide, and 1" thick, but any piece of wood containing 144 cubic inches of wood is considered one board foot in size. There are multiple methods of estimating usable board feet from a standing tree, but you can use a simple estimate. For more complicated and exact systems, such as those used by the U.S. Forestry Service, see "Ohio State University: Measuring Standing Trees" in Resources.
Simple Estimate for Board Feet
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Step 1
Measure the merchantable height of the tree, generally considered the point at which the tree trunk is 10 inches in diameter, with the measuring tape.
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Step 2
Measure the base diameter of the tree and divide by two to calculate the radius.
Step 3
Calculate the area of a cross-section of the tree as the radius of the tree, squared, multiplied by pi. (A=r^2 x p)
Step 4
Calculate the volume of the tree as Cubic Feet = Area (ft) X Height (ft) / 4. The division by 4 is to generally estimate the effect of the tree's taper as it gets taller.
Step 5
Multiply the cubic feet result of the volume by 12, to find the number of board feet in the tree.
Using Tables to Calculate Board Feet
Step 1
Measure the merchantable height of the tree, generally considered the point at which the tree trunk is 10 inches in diameter.
Step 2
Measure the base diameter of the tree and divide by two to calculate the radius.
Step 3
Estimate usable board feet either via the Doyle rule or the International 1/4 Inch rules using the tables at "Ohio State University: Measuring Standing Trees" in Resources.