On June 20, 1995, at 1600 central daylight time, a Bell 47G3B1, N101VB, was substantially damaged following a collision with terrain during a forced landing near Livingston, Alabama. The commercial pilot received serious injuries in the accident. The aircraft was being operated under the provisions of CFR Part 91 by Morris Helicopters of Deatsville, Alabama. Visual meteorological conditions existed at the time, and no flight plan had been filed for the local agricultural flight. Witnesses in the area reported hearing the helicopter engine make a popping noise. The helicopter was observed descending and turning toward an open area just prior to impact with the terrain. The pilot stated that he was returning to the truck platform to reload with chemicals, when the aircraft engine lost power. He executed an autorotation into field, but was unable to see the ground due to the vegetation. He stated that the aircraft fell about 20 feet prior to impacting the terrain. Examination of the aircraft engine revealed that there was continuity of the engine drive train. The induction system was clear of obstructions, and the air filter was intact. The carburetor throttle valve, main nozzle and venturi were intact. There was fuel found in the carburetor bowl, and the fuel was free of contamination. The engine spark plugs appeared to have moderate wear, and the electrode gaps were the correct spacing. The magnetos, and ignition wiring were examined and found to be operational.