A TWIN ENGINE PIPER PA 34-200T COLLIDED WITH TREES IN HILLY TERRAIN 8 MILES SOUTHWEST OF THE AIRPORT AFTER TAKING OFF IN FOGGY CONDITIONS. THE NONMULTIENGINE/INSTRUMENT RATED CERTIFICATED PRIVATE PILOT REPORTED HE LOST POWER IN THE LEFT ENGINE AND DID NOT PERFORM THE EMERGENCY PROCEDURES FOR THE LOSS OF ENGINE POWER. EXAMINATION OF THE ENGINE DID NOT REVEAL ANY MECHANICAL FAILURES OR MALFUNCTIONS. SUBSEQUENT INVESTIGATION OF THE PILOT REVEALED THAT HIS MEDICAL CERTIFICATE HAD EXPIRED, HE DID NOT HAVE A AIRPLANE MULTI-ENGINE CLASS RATING, AN INSTRUMENT AIRPLANE RATING OR PROOF OF A CURRENT BIENNIAL FLIGHT REVIEW. REVIEW OF THE PILOT'S AIRMEN RECORDS, RETAINED BY THE FAA IN OKLAHOMA CITY, OKLAHOMA, REVEALED THREE PREVIOUS SUSPENSIONS OF THE PILOT'S PRIVATE PILOT CERTIFICATE FOR VIOLATIONS OF THE FEDERAL AVIATION REGULATIONS. THE MOST RECENT THIRD CLASS MEDICAL CERTIFICATE WAS ISSUED TO THE PILOT ON MAY 4, 1983, AND HAD EXPIRED.