On May 21, 1995, at 1420 hours Pacific daylight time, a Robinson R-22 helicopter, N8363Q, collided with a tree near Greens Creek Campsite about 25 miles north of Redding, California. The pilot was completing a local visual flight rules personal flight. The helicopter, registered to and operated by a private individual, sustained substantial damage. The certificated commercial pilot and his passenger sustained minor injuries. Visual meteorological conditions prevailed. The flight originated from a houseboat at Shasta Lake at 1415 hours. National Transportation Safety Board investigators interviewed the pilot via a telephone on May 21, 1995. The pilot said that he departed the open area and intended to land at the Greens Creek Campsite. He said that the landing area sloped downward and that he landed the helicopter at the campsite, but did not fully lower the collective. He felt uncomfortable with the landing and then raised the helicopter to a hover. While the helicopter was hovering, a gust of wind blew the helicopter into the trees. The pilot said the helicopter did not experience any preimpact malfunctions or failures. The pilot repeated his telephone statement in the Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2. He added, however, that when the helicopter left skid touched down, the left skid was on an uneven surface and he felt the helicopter settling back. He aborted the landing and raised the helicopter to about a 2-foot hover and then the helicopter rolled to the left in a tail-up attitude. It appeared that the helicopter was " . . . hit on the right side by a strong gust of wind . . . ." The pilot added the appropriate cyclic and collective controls input and the helicopter responded by " . . . rolling back to the right . . . ." The helicopter tail rotor then struck the trees. Ground witnesses confirmed the pilot's statement with respect to the aborted landing and collision with the trees. The witnesses said that calm wind conditions existed on the lake with intermittent gusty wind conditions at the accident site.