Before the local flight, the pilot confirmed the left fuel tank was about ¼ full and the right fuel tank was about ¾ full of fuel. About 30 to 40 minutes into the flight, the engine experienced a loss of power. The pilot attempted to restart the engine by adjusting the mixture and utilizing the fuel boost pump. Unable to restart the engine, he maneuvered the airplane to a nearby airport and extended the landing gear, then realized the airplane could not glide to the airport, so he retracted the landing gear. He then elected to make a forced landing to a field and extended the landing gear. The airplane landed in the field and continued into a tree line where it came to rest upright. The airplane sustained substantial damage to the leading edges of both wings. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation. A postaccident examination of the fuel tanks by the pilot revealed that the left tank was empty and the right tank was about ¾ full. The pilot stated that the left tank was utilized for the entire flight and that he did not switch fuel tanks.