On May 15, 2003, at 1100 central daylight time, a Piper PA-18-135, N2581A, piloted by a private pilot, sustained substantial damage during an in-flight collision with the terrain near Prescott, Wisconsin. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot reported minor injuries and the passenger reported serious injuries. The local flight departed a private airstrip near Prescott, Wisconsin, at 1000. The pilot stated that during landing the airplane was still floating in ground effect as he approached the south end of the runway, and he decided to go-around. The pilot reported he increased engine power to full, turned off the carburetor heat, and left the wing flaps fully extended. The pilot stated the airplane was unable to clear a line of trees at the end of the runway. The pilot indicated he banked the airplane to the left, "but still felt [he] could not clear the north-south tree line to the east." The pilot stated he "tightened the turn to avoid [the trees]." The pilot reported the airplane lost altitude and impacted the terrain. The pilot reported there were no mechanical malfunctions or failures during the accident flight.