I made this type of tree in another pattern. The bottom block is oblong with small squares sown onto the ends and cut off at an angle. For instance in my pattern the bottom blocks were one green piece that was 2 1/2" x 8 1/2" with the lighter color fabric being 2 1/2" square and one 2 1/2" square sown to each end of the longer green piece at an angle and the remainder cut off.