On September 26, 1999, at 1200 hours Pacific daylight time, a Cessna 172N, N738ZQ, drug the left wing while landing at the Nut Tree Airport, Vacaville, California. The aircraft, owned and operated by the pilot, was substantially damaged. The private pilot and passenger were not injured. The personal cross-country flight was conducted under the provisions of 14 CFR Part 91 and originated from the Palo Alto, California, airport, about 1115, and was en route to Vacaville. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he encountered continuous light to moderate turbulence along his route of flight. When he neared the destination airport, he overflew the field to check the windsock. He stated that the winds appeared to be coming straight down runway 02. The pilot asked for a wind check over the common traffic advisory frequency and was told that the wind velocity was 10 to 15 knots. He stated that the final approach was very bumpy. As he initiated the landing flare, he noted that the windsock reflected that the winds had changed direction and were now about 90 degrees to his left. The pilot reported that as he applied full power to initiate a go-around the right wing rose up and the airplane turned left into the wind. The stall warning horn went off and the airplane began to settle. The pilot applied full aileron and right rudder while continuing the go-around procedure. He felt the aircraft hit the runway and bounce back up into the air. He stated that it felt as if the airplane had landed on the left gear only. He reported that the wings were level but the airplane had veered left of the centerline. He held the nose down and accelerated in ground effect. The pilot reported that once he attained a positive rate of climb and reached 500 feet agl, he looked at the left landing gear and noted that it appeared undamaged. He decided not to make a second attempt to land and instead began a return trip to Palo Alto. He reported that the arrival and landing at Palo Alto were uneventful. After shutdown, he placed chocks under the left tire and examined the propeller and right tire for damage, but found none. The pilot reported that subsequent examination of the airplane revealed left wingtip, aileron, and secondary spar damage. He further reported that he had not experienced any mechanical problems with the aircraft prior to the accident. The recorded weather data from the Vacaville airport weather observation facility reflected that the winds at 1153 were from 350 degrees at 12 knots, gusting to 18 knots.