DURING A NIGHT ARRIVAL, THE PLT REPORTED THAT HE HAD THE ARPT IN SIGHT & CANCELED HIS IFR FLT PLAN. A WITNESS SAW THE LIGHTS OF THE ACFT AS IT CIRCLED THE DESTINATION ARPT. HE REPORTED THE ACFT HAD TURNED LEFT TO A SOUTHERLY HEADING, & SHORTLY THEREAFTER, HE SAW A FLASH OF LIGHT. THE WITNESS WENT TO THE ARPT & OBSERVED THAT THE ARPT LIGHTING WAS ON. ALSO, HE NOTED THAT THERE WAS NO GROUND FOG & HE COULD SEE STARS OVERHEAD. A SEARCH WAS INITIATED, BUT THE ACFT WAS NOT FOUND UNTIL 0950 EST THE NEXT MORNING. THE ACFT HAD COLLIDED WITH TREES ABOUT 3000 FT SOUTHWEST OF THE WEST END OF RWY 9/27, THEN CRASHED & BURNED. INITIAL IMPACT WAS WITH A 70 FT TREE AT AN ELEVATION OF ABOUT 690 FT MSL WHILE THE ACFT WAS ON A SOUTHERLY HEADING. THE ARPT ELEVATION WAS 670 FT MSL. NO PREIMPACT PART FAILURE OR MALFUNCTION WAS FOUND. APRX 32 MI EAST AT PELLSTON, MI, THE 2150 EST WX WAS, IN PART: 5000 FT SCATTERED, 10,000 FT BROKEN, VISIBILITY 4 MI.