Estimating Board Feet

Board feet is the measurement used to determine the amount of wood in a tree.  A board foot is a foot wide, a foot long and one INCH thick.  So one board foot is 144 cubic inches (12" x 12" x 1).  One cubic foot of wood contains 12 board feet.

Question:  How many board feet are in a board that is 4 inches wide, 8 feet long, and one inch thick?

Solution:  Hint - convert all measurements to inches, then multiply length x width x height.
                 4" x 96 " x 1" = 384 cubic inches = 2 2/3 Board Feet

Now you try one...
Question 1:  How many board feet are in a piece of plywood that is 4 feet wide, 8 feet long, and 1/2 inch thick?

Now challenge yourself...
Question 2:  How many board feet are in a stack of 15 boards each of which are 10 feet long, 6 inches wide, and 2 inches thick?

Estimating Board Feet of a Tree
1.  Find the diameter of the tree approximately 4.5 feet above the ground.  (Hint: Measure the circumference and convert to diameter.)

2.  Find the tree height.  Stand 66 feet from the base of the tree.  Use a clinometer (or download a clinometer app on a tab or phone) to determine the percent of incline from your viewpoint to the top of the "usable tree."  In order to be mathematically accurate, you must take into account that your eyesight and the base of the tree are not on the same level.  To account for this, you can do one of two things.  First you could lay on the ground level to the base of the tree.
To find the tree height:  Multiply the percent reading times 66' (the distance from the base).

Or...stand normally and let this be your A(+) reading.  Then use the clinometer to measure from your viewpoint to the bottom of the trunk.  This will be your B(-) reading.
To find the tree height:  [A(+) - B(-)]*66'

3.  Find the tree volume.  (Before beginning calculations, make sure all your measurements are in feet.)  Use the formula for volume of a cylinder, but divide the result by 4 to account for the taper of the tree.

4.  Convert cubic feet to board feet.  (Remember:  There are 12 board feet in each cubic foot of lumber.)

NOTE:  This estimate shows the total volume of wood in the tree.  Not all of that wood would be considered "useable."

It is helpful to create a spreadsheet to make calculations simpler.  See attached file below.
Estimating Board Feet Spreadsheet