The pilot reported that during a postmaintenance flight, while remaining in the airport traffic pattern, the engine lost all power. The pilot selected an area of tree-covered terrain as a forced landing site, resulting in substantial damage to the wings and fuselage. He stated that the reason for the loss of engine power was due to fuel starvation, and that he did not verify the position of the fuel selector valve before the flight. He added that when the airplane recently underwent maintenance, the fuel selector valve handle was positioned to the right fuel tank, which had a slight amount of fuel remaining. The pilot said that he routinely used the left fuel tank, which contained sufficient fuel for the flight. The pilot reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.