The pilot of the Cessna 172N stated the airplane was in cruise flight when the engine sputtered, and stopped producing power. The pilot then performed a forced landing to trees, resulting in substantial damage, but neither he nor the two passengers were injured. The pilot said he immediately egressed the airplane, checked both fuel tanks, and found both were empty. Examination of the fuel tanks by a Federal Aviation Administration inspector revealed they were intact, and no evidence of fuel, fuel spillage, or fuel odor was identified at the scene. The pilot stated that he departed his home airport with full tanks earlier in the day and recorded 3.2 hours on the hobbs meter. Several stops were made during the day, which involved six takeoffs and climbs to altitude. In a written statement, the pilot added, "Physically checking the fuel tanks for fuel, instead of relying on [the] hobbs meter and an assumed gallons per hour fuel consumption rate, could have prevented this accident."