The pilot reported that, during approach, while flying from the rear seat of the tandem-seat, high-wing airplane, he "needed to lose speed and altitude." He placed the airplane in a right-wing-low, forward slip, and he added that the airplane had poor forward visibility at slower speeds. He aligned the airplane with the center of the runway and "pulled the nose up slightly to slow [down]," and a "wind gust" came from the right and "pushed" the airplane over the trees. He "saw [the] tree tops coming up fast under [his] left wing," and "out of shear instinct, [he] banked slightly right to avoid going in nose first." The airplane collided with the tree tops. The airplane sustained substantial damage to both wings and the empennage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The automated weather observation system about 3 nautical miles from the accident site, about the time of the accident, reported that the wind was variable at 3 knots. The pilot landed to the southwest.