This constant represents the volume of a face cord (or rick) of wood cut that has been cut to a standard 16 inch length.
There is no definitive standard length to have the wood cut but a very common length is 16 inches and because of that a single stack of this wood having the same length and height of a standard cord of firewood is called a "Face Cord". It is called this because it is like the face of a full cord, which might typically be three stacks of 16 inches long wood or two stacks of 24 inch long wood.
You may select other than cubic feet as the unit of volume.
Definition of a Cord
A cord of wood is a standard measure of firewood which is defined to be a tightly stacked pile of wood that is 4 ft. by 4 ft by 8ft -- or 128 cubic feet.
To make the measurement of the stack of wood easier, a cord is usually stacked between straight uprights separated by eight feet, as shown in the picture below, making the calculation a straightforward rectangular volume.
Definition of a Face Cord
A common length for standard firewood pieces is 16 inches. If you create a single stack of these 16 inch lengths of firewood that is 4 feet high and 8 feet long, you have a Face Cord. This is shown in the following image.
There is a lot of discussion that the length of the wood in a Face Cord can vary in length but it is so common that the length of the wood in a face cord is cut to 16 inch lengths that the only reason someone would bother to try to define it differently would probably be to try to cheat you. Therefore, the 16 inch by 4 feet high by eight feet long definition of a Face Cord is as standard as it gets and used probably by 95% of people dealing in firewood.
Note also that most states have legal definitions of a cord and in some states they include a definition of a Face Cord and in those cases where they legally define a Face Cord they define it having a minimum of 16 inch pieces of wood. 16 inch lengths became common because the length is easy to handle and fits mos any fireplace.
Of course, you can always get someone to cut your firewood in shorter OR longer lengths if you have a smaller or bigger fireplace but the volume dimensions of the Cord or Face Cord should still apply.
