AS THE GEAR WAS RETRACTING AFTER TAKEOFF, THE ACFT BEGAN TO LOSE POWER. THE PLT COULD DETECT NO YAW TO EITHER SIDE. WHEN THE ACFT WAS ABOUT 50 FEET OFF THE GROUND, THE TWR INFORMED THE PLT THAT VAPOR OR SMOKE WAS TRAILING FROM THE LEFT ENG. THE PLT ACKNOWLEDGED THAT HE HAD A PROBLEM. THE PLT THEN PLANNED AND EXECUTED A FORCED LANDING INTO TREES AT THE DEPARTURE END OF RWY 21 AT LYNCHBURG MUNICIPAL AIRPORT. EXAMINATION OF THE WRECKAGE BY AN FAA REPRESENTATIVE REVEALED LARGE QUANITIES OF JET FUEL THROUGHOUT THE FUEL SYSTEM OF THE ACFT. REFUELING OF THE ACFT IMMEDIATELY PRIOR TO THE ACCIDENT WAS ACCOMPLISHED BY AN EXPERIENCED LINEMAN WHO HAD COMPLETED THE GENERAL AVIATION MANUFACTURERS ASSOCIATION'S LINEMAN TRAINING VIDEO TAPE PROGRAM. THE ACFT AND FUEL TRUCKS WERE MARKED IN STANDARD FASHION WITH APPROPRIATE PLACARDS.