The pilot reported that he was conducting a local sightseeing flight in visual meteorological conditions when the airplane inadvertently entered instrument meteorological conditions. While maneuvering, he lost visual reference with the ground. The airplane entered a steep descending turn, and collided with trees. Both wings separated from the airframe and the fuselage was crushed. Weather conditions reported at an airport that was located about 17 nautical miles from the accident site, included, overcast clouds at 1,100 feet above ground level. The elevation of the accident site was about 1,700 feet mean sea level. The pilot reported that he experienced no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.