On November 23, 2007, about 1615 Pacific daylight time, a Cessna 150L, N19298, experienced a partial loss of engine power and made a forced landing near Woodland, Washington. Aero Maintenance, Inc., was operating the airplane under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) and the student pilot undergoing instruction were not injured; the airplane sustained substantial damage. The local instructional flight departed Pearson Field Airport, Vancouver, Washington, about 1545. Visual meteorological conditions prevailed, and no flight plan had been filed. In a written report to the National Transportation Safety Board, the CFI stated that she instructed her student to maintain an altitude of 2,000 feet mean sea level (msl). She noted that the airspeed indicator was displaying a higher then normal airspeed and she instructed her student to reduce rpm. As the airplane descended, the student pitched the nose up to gain altitude and reduce the airspeed. The CFI reported that the airplane was not able to climb due to the loss of power. She turned on the carburetor heat and increased the throttle to full power. After 30 seconds, there was no increase in engine performance and she decided to conduct a forced landing to a nearby field. Upon landing in the soft field, the nose landing gear collapsed, and the airplane came to rest on its nose. The pilot reported no mechanical malfunctions with the airframe. She did however, suspect carburetor ice for the partial loss of engine power. The CFI reported a broken layer of clouds at 2,800 feet msl. Also, she noted at 2,000 msl, the temperature was 60 degrees Fahrenheit with a relative humidity between 55 to 59 percent. The closest weather reporting station was noting a temperature of 66 degrees and a dew point of 41 degrees. According to a carburetor icing probability chart, these conditions were conducive for moderate icing with cruise power and serious icing at descent power.