On July 7, 1999, about 1530 Pacific daylight time, a Piper PA-22, N4707C, registered to and operated by the pilot, was substantially damaged during an off airport forced landing following a sudden loss of engine power. The accident occurred approximately three miles west of Cottage Grove Airport, Cottage Grove Oregon. The private pilot, the sole occupant of the aircraft, was not injured. No flight plan was filed and visual meteorological conditions prevailed for the 14CFR91 personal/pleasure flight. The flight originated from Gasquet Airport, Gasquet, California approximately one hour and 30 minutes prior to the accident. While in a cruise configuration, approximately 3,500 feet MSL, the aircraft experienced a sudden loss of engine power. The pilot initiated an off-field landing in a open field. During the landing roll-out, the aircraft's nose wheel struck a large rock causing the aircraft to nose over, resulting in substantial damage to the aircraft's wings and fuselage. The pilot stated he ran the left fuel tank dry. He selected the right fuel tank, but was unsuccessful in restarting the engine and elected to land in a nearby field. The pilot reported the right fuel tank was full at the time of the accident. No evidence was found to indicate a mechanical failure or malfunction.