The volume of the log will be calculated using quarter girth formula
V = (g/4)2 * l
π of value 3.14 is approximated to 4. Thus this formula underestimates the volume almost 21.5% as compare to full circular volume. It is known as Hoppus’ Formula in Britain. Even if the log had no taper, the volume of the square timber would be 2r2l.