WHEN POWER WAS REDUCED TO BEGIN INITIAL DESCENT FOR APPROACH AND LANDING THE ENGINE LOST POWER AND THE PILOT PERFORMED A FORCED LANDING ON A ROAD. THE ROAD HAD A 4% UPGRADE AND CURVED TO THE RIGHT. DURING THE ROLLOUT THE OUTBOARD END OF THE RIGHT WING STRUCK A TREE DAMAGING THE WING CARRY THROUGH SPAR. METALLURGICAL TESTING REVEALED THE CAUSE OF THE POWER LOSS TO BE FAILURE OF THE GAS PRODUCER TURBINE.