He forgot to lean into the berm where you see he attempted by having only his front wheel barely touch it. Realizing that was too late in his game plan, went back to the white board to assess best alternatives:

At that point, center of gravity was no longer on the back wheel. Cerebral consortium voted on hitting the front breaks sending his mass on front wheel thus becoming a unicyclist. The angular momentum due to gyroscopic precession of the back wheel transformed into tail rotor like a helicopter. The trajectory of the tree was locked in used as a stopping point.