On April 26, 2002, at 1330, central daylight time, a Cessna 150B, N1299Y, registered to a private owner, impacted the runway during a go-around, at Enterprise Municipal Airport, Enterprise, Alabama, while conducting traffic pattern work. The instructional flight was conducted under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual meteorological conditions prevailed at the time of the accident. The airplane was substantially damaged and the Commercial rated helicopter pilot was not injured. The flight originated from Enterprise, Alabama, at 1315. According to the pilot, during his approach to land, he was about 15 feet above the ground, close to stall speed, when the left wing dropped. He then added full power for a go-around. During the go-around the airplane continued to bank left and pointed towards the trees. The pilot could not climb over the trees so he continued the left turn to avoid the trees. He attempted to land the airplane on grass adjacent to the runway. The front nose wheel impacted the ground, the propeller struck the ground with power, and the airplane ended up facing the southwest direction. According to a witness, the pilot was conducting short field touch and go landings to runway 5. Before touchdown, during the approach, the pilot aborted the approach to land, and added full power for a go-around. The witness stated during the go-around the airplane banked hard to the left, stalled, impacted the runway and came rest approximately 200 feet to the right of runway 5. The pilot prior to the accident reported no mechanical malfunctions. Examination of the airplane revealed, the airplane was to the left of runway 5, approximately 333 feet northwest of the runway going in the opposite direction. The nose wheel was separated from the airplane and came to rest in front of the airplane. The nose of the airplane was suspended off the ground by a tree limb. The nose wheel fork was bent aft almost to the fuselage. Both left and right wingtip caps were buckled.