At approximately 12:40 Pacific time, a Piper PA-24 lost engine power in flight and was substantially damaged when the pilot made an intentional gear-up landing in a field. The pilot and passenger where not injured. The pilot said the airplane was in cruise flight when he noticed the exhaust gas temperature had decreased. He did not sense any drop in rpm and he did not check to see what the manifold pressure was. He applied carburetor heat for a couple of seconds but saw no indication that there was any ice accumulation. Less than a minute later the engine quit. The aircraft descended through the overcast and the pilot executed a forced landing in an open field located in densely forested terrain.