Whether you are taking down trees in your landscaping project or figuring out how much firewood you will need for the winter, being able to estimate the cord total from your trees is a useful ability. A cord of wood equals 128 cubic feet; to visualize that, think of a stacked pile of logs that is 4 feet high, 4 feet wide and 8 feet long. That is hard to translate to standing trees, but with basic geometry and a standardized table, you can get a good idea of what your harvest will be.
Measure the circumference of the tree at a height of 4 1/2 feet off the ground.
Divide the circumference by 3.14 to get the diameter.
Refer to the University of New Hampshire's "Estimating Firewood" (see Resources). Match up your diameter to the nearest one listed on the table. For example, if the diameter of your tree is 12 inches, it will yield 0.3 cords, or about one-third of a cord of wood. A tree with a diameter of 22 inches will yield a full cord of wood.