On November 21, 2004, about 1430 eastern standard time, a Cessna 172E, N3750S, was substantially damaged during a precautionary landing near Rupert, West Virginia. The certificated private pilot and two passengers were not injured. Visual meteorological conditions prevailed. The airplane was not operating on a flight plan between Johnston County Airport (JNX), Smithfield, North Carolina, and Summersville Airport (SXL), Summersville, West Virginia. The business flight was conducted under 14 CFR Part 91. According to the pilot, in the vicinity of Roanoke, the air temperature was 35 degrees at 4,500 feet, and the cabin heat was turned on. About 10 to 20 minutes north of Roanoke, the airplane encountered light mist, and just past Rupert, West Virginia, with deteriorating weather, the pilot decided to turn around. Shortly thereafter, "the engine was not making full power and was missing. Carburetor ice was suspected with the high humidity and the low outside air temperature." The pilot applied carburetor heat for about 1 minute, but it had no effect. The engine continued to run roughly while in cruise flight, and the engine rpm decreased to approximately 2,000 to 2,100 rpm. The pilot then reapplied carburetor heat, but there was no improvement in engine performance. The pilot felt that he could not safely transition higher terrain en route to his destination, so he decided to make a precautionary landing on a logging road. During the landing, the pilot noticed a bulldozer on the road. The pilot swerved the airplane off the road, and the left wing impacted a tree. The closest airport with recorded weather was Greenbrier Valley Airport (LWB), Lewisburg, West Virginia, about 20 nautical miles to the southeast. The airport did not have the capability to record cloud cover, but did record, about the time of the accident, winds from 270 degrees at 3 knots, mist, temperature 48 degrees F, dew point 48 degrees F, and a barometric pressure of 30.25 inches of mercury.