DURING TAKEOFF, THE AIRPLANE HAD REACHED ABOUT 125 FT ABOVE THE RUNWAY, WHEN THE ENGINE STARTED TO LOSE POWER. THE PILOT SAID, '. . . THE ENGINE STARTED TO LOSE R.P.M. . . . IT DROPPED TO . . . 1500 R.P.M.'S . . . I ESTABLISHED A GLIDE WHILE APPLYING CARBURETOR HEAT . . . THE AIRPLANE THEN STARTED SINKING FASTER . . . I THEN APPLIED FLAPS, CLOSED THE THROTTLE, DID A FULL STALL, LANDING INTO THE TOPS OF THE TREES.' THE PILOT ALSO SAID, 'CARB ICING CONDITIONS PRESENT, MELTING SNOW ON GROUND, 45 DEGREE F.' A POST-ACCIDENT ENGINE RUN-UP WAS MADE, BUT NO DISCREPANCY WAS FOUND.