The airplane was substantially damaged when it impacted a deer fence and terrain during an approach to landing on runway 20 (5,000 feet by 100 feet, asphalt). The pilot stated that while turning base leg to final, she noticed that the airplane was too low and appeared to be sinking too fast. She reported that she tried to increase engine power, but the engine did not respond. The airplane then struck a 10 to 12 foot high deer fence surrounding the airport and subsequently impacted terrain short of the runway. A post accident inspection of the engine and airplane was conducted. The following items were noted and inspected: 1) In the cockpit, the throttle and mixture were found in the full forward (full throttle and full rich) position and the carburetor heat was found in the off position; 2) the carburetor heat was cold (off) at the carburetor air box; 3) the spark plugs were clean and showed no fouling; 4) a "thumb" compression test of the cylinders exhibited compression and suction; 5) both magnetos sparked during a spark test; 6) fuel was found in the main fuel strainer; 7) no fuel was found in the carburetor, the carburetor bowl, or the fuel line going to the carburetor; 8) the fuel strainer and carburetor fuel screens were clean; 9) the oil filter was clean; and 10) the exhaust system had no loose baffles. According to the carburetor icing probability chart, the temperature and dewpoint at the time of the accident showed that serious carburetor icing while using descent power settings was possible. The pilot reported using the carburetor heat during the approach to landing. Weather conditions recorded near the time of the accident were: Wind 200 degrees at 4 knots, visibility 10 statute miles, sky condition clear, temperature 28 degrees Celsius (C), dewpoint 16 degrees C, altimeter setting 30.04 inches of mercury.