The crew were carrying out a goat eradication program at the time of the accident. The aircraft was transiting from the hover to forward flight, at approximately 50 feet above ground level, when the engine suddenly stopped. The pilot immediately entered autorotation and attempted to cushion the landing by increasing the collective pitch. The aircraft touched down heavily, tail first, before colliding with trees. An inspection of the aircraft failed to disclose any reason for the sudden engine stoppage. Weather conditions were conducive to the formation of carburettor ice however, the pilot had carburettor heat selected at the time of the accident. The reason for the sudden stoppage could not be determined.