On August 12, 2007, about 1830 eastern daylight time, a Piper J-3, N6429H, was substantially damaged during a forced landing in Frenchtown, New Jersey. The certificated private pilot and the passenger incurred minor injuries. Visual meteorological conditions prevailed, and no flight plan had been filed for the local flight from Vansant Airport (9N1), Erwinna, Pennsylvania. The personal flight was conducted under 14 Code of Federal Regulations Part 91. According to the pilot, he took off about 1815, and climbed the airplane to 1,400 feet above mean sea level. He then turned left over the Delaware River, applied carburetor heat to the Continental C85-12 engine, and descended to approximately 500 feet above the water. He then secured the carburetor heat and opened the throttle, but there was no engine response. The engine "sounded o.k." but remained at idle power regardless of throttle position. The pilot checked that the fuel selector was on, and 300 to 400 feet above the river, turned toward the shoreline. He attempted a forced landing to a field; however, prior to reaching it, the airplane descended into a tree. There was no on-scene examination of the airplane. It was removed from the tree, transported to a storage facility in Delaware, and subsequently sold for salvage. While in the storage facility, the owners performed a cursory examination, with no preaccident mechanical anomalies noted. Weather, reported at an airport 12 nautical miles to the east, at 1854, included winds from 260 degrees true at 6 knots, visibility 10 miles, a broken cloud layer at 7,000 feet, temperature 30 degrees Celsius (C), dew point 13 degrees C, and an altimeter setting of 29.96 inches Hg. Plotting the temperature and dew point values on a carburetor icing chart yielded a probability of serious carburetor icing at glide power.