On January 13, 2003, at 1600 central standard time, a Piper PA-38-112, N2400K, collided with a sapling during an off airport forced landing while on approach to land on runway 25 at the Mansfield Municipal Airport (03B), Mansfield, Missouri. The pilot was not injured. The airplane was substantially damaged. The 14 CFR Part 91 flight was operating in visual meteorological conditions without a flight plan. The flight last departed the Mountain Grove Memorial Airport, Mountain Grove, Missouri, at 1535. The pilot reported that she flew to 03B to practice a couple of touch-and-goes. She stated she entered the traffic pattern and pulled the power back when she was 180 degrees from the end of the runway. She stated that after she leveled off on base leg, she realized that the wind was pushing her away from the runway so she added power, but there was no response from the engine. The pilot stated she tried adding a little more power, but again there was no response. She stated she then pulled the throttle back and advanced it to the full power setting, but there was still no response from the engine. The pilot stated she chose a two-lane dirt lane on wooded farmland on which to land. She stated the landing gear width was wider than the lane, and the land on both sides of the lane was uncut grass, brush, and trees. She continued to report, "There were soft spots in the earth to the side of the lane. This caused the airplane to rock somewhat from side to side as it rolled, alternately dragging one wingtip then the other on the ground. There was a very large, very solid-looking dead tree coming up on the right side of the lane. Ultimately, the left wing clipped a sapling surrounded by brush, ground-looping the airplane 180 [degrees], then it slid sideways to the outside of the loop for another 10 or 12 feet and came to rest suddenly." The pilot reported that the airplane had just had an annual inspection and the engine was overhauled. During the overhaul an STC was installed upgrading the engine from 112 to 125 horsepower. She stated that her A&P mechanic instructed her to keep the engine rpm up for a while since the engine was just overhauled. She stated because of this, she flew the entire flight at 2,400 rpm until pulling the power back in the traffic pattern at 03B. The pilot reported that she did not use carburetor heat at anytime during the flight. Following the accident, the engine was started and it operated normally. The temperature and dewpoint reported at Springfield, Missouri, 41 nautical miles northwest of the accident site, at 1553, were 1 degree Celsius and -1 degree Celsius, respectively. According to the Transport Canada Carburetor Icing Chart, these conditions are conducive for serious icing at any power setting. The Lycoming O-235-C Series engine manual, page 3-7, states, "(3) Landing Approach - In making an approach for a landing, carburetor air heat should generally be in the "Full Cold" position. However, if icing conditions are suspected, the "Full Heat" should be applied. In the case that full power need be applied under these conditions, as for an aborted landing, the carburetor heat should be returned to "Full Cold" after power application. See aircraft flight manual for specific instructions." The PA-38-112, Pilot Operating Handbook, pages 4-21and 22, state, "Carburetor heat should not be applied unless there is an indication of carburetor icing, since the use of carburetor heat causes a reduction in power which may be critical in case of a go-around. Full throttle operation with carburetor heat on can cause detonation."