On June 14, 2001, about 1300 eastern daylight time, a Cessna 150, N1525Q, was substantially damaged during a forced landing at the Lincoln Regional Airport (LRG), Lincoln, Maine. The student pilot was not injured. Visual meteorological conditions prevailed for the instructional flight that departed Millinocket, Maine, about 1245. No flight plan was filed, and the solo flight was conducted under 14 CFR Part 91. The pilot preflighted the airplane, and added about 5 gallons of automotive fuel. He estimated that before adding the fuel, the airplane had approximately a 50:50 ratio of 100LL to automotive fuel. After fueling, he let the airplane sit for about an hour before draining the fuel sumps. The fuel samples were blue in color, and absent of debris or water. The pilot then boarded the airplane, started the engine, and taxied short of the runway to perform the engine run-up checks. The pilot did not notice any anomalies when he checked the magnetos or carburetor heat. The pilot then departed Lincoln, and flew to Millinocket, Maine, to pickup his flight instructor. After landing, the instructor boarded, and the two completed a cross-country flight to Augusta, Maine. The pilot then flew his instructor from Augusta back to Millinocket, and then departed solo back to Lincoln, Maine. Once in the Lincoln area, the pilot maneuvered the airplane onto a left downwind to land on Runway 35. When the airplane was abeam the middle of the runway, the pilot selected the carburetor heat to "ON." Abeam the landing threshold, he reduced the engine rpm to 1,500, and selected 10 degrees of flaps. On final, he selected 20 degrees of flaps, and made a radio announcement on CTAF stating his intentions. The pilot added that since the airplane was a little higher than "normal" he increased the flaps to 30 degrees. While on final and approximately 600 feet agl, the pilot decided that the airplane was not in a position to safely continue the approach. He initiated a go-around, selected carburetor heat to "OFF," applied full power, and allowed the airplane to accelerate. By the time the airplane was approximately half way down the runway, the pilot had retracted the flaps, and initiated a climb. A couple of seconds into the climb and without warning, the engine lost power. The pilot surveyed the area, and decided to attempt a forced landing to Runway 35. He made a 360-degree turn to position the airplane for the forced landing. The airplane touched down "fast," about half way down the runway, and about 20 feet off to the right of the runway, on the grass. The pilot applied the brakes, but found them ineffective on grass. As the airplane approached a line of trees that were 2 to 4 inches in diameter and approximately 30 feet high, he pulled back on the yoke, and the airplane became airborne. The airplane went into the trees nose high, and came to a stop. The pilot noticed fuel running down the right door. He secured the electric and fuel systems, and then egressed via the left door. According to a mechanic that examined the airplane under the direction of a Federal Aviation Administration inspector, the airplane was removed from the woods intact. The left fuel tank was undamaged and had approximately 5 gallons of fuel in it. The right tank displayed some impact damaged and was leaking. The right tank also contained about 5 gallons of fuel. An engine run was then completed. During the first attempt to start the engine, it backfired, but then started and ran smoothly. Engine rpm was limited to 1,200 because of propeller damage. A magneto check was preformed at 1,200 rpm, and engine rpm dropped approximately 100 rpm for both magnetos. After securing the engine, the mechanic disconnected the fuel line between the gascolator and carburetor. He then activated the electric-driven fuel pump. Initially, fuel was expelled at what the mechanic classified a "normal" rate, but then slowed. With the pump functioning normally, the fuel flow oscillated between "normal" and a reduced rate. The gascolator was examined and the fuel screen was found absent of debris. The carburetor bowl was also examined. The bowl contained fuel, and was absent of debris or water.