The airplane was substantially damaged when it collided with a fence and trees during a forced landing at 1545 Eastern time. Visual conditions prevailed. The private pilot reported minor injuries. The pilot later stated he was in cruise flight at 5000 feet when the engine started to run a little rough. A short time later he smelled fuel. He opened air vents but the smell persisted. After querying ATC on the nearest airports location, the pilot observed an open field and initiated a forced landing to the field. The engine stopped less than a minute after he informed ATC that he needed to land. The airplane touched down in the field, went through a fence, collided with trees and came to a complete stop.