On April 21, 1996, about 1700 mountain daylight time, N8873S, a Cessna 150, operated by the owner/pilot, collided with a tree in Salt Lake City, Utah, during a forced landing. The forced landing was precipitated by a loss of engine power during cruise flight. The airplane was substantially damaged and the student pilot received minor injuries. Visual meteorological conditions prevailed and a visual flight rules (VFR) flight plan was filed. The instructional flight departed from West Jordon, Utah, and was conducted under 14 CFR 91. The student pilot stated that the engine suddenly "lost power." She stated that the left and right cockpit fuel gages read 1/2 and 1/4 respectively. After the engine quit, she attempted to land at a shopping center parking lot. As she got closer to the ground, she decided to land on a roof. She stated that she then saw power lines and "aimed for a 30 [foot] pine tree." According to an FAA aviation safety inspector from Salt Lake City, Utah, one of the airplane's wings collided with a flexible flag pole. The inspector stated that the airplane was slowed by the impact with the flag pole; the airplane then pivoted around the pole and into the upper branches of a pine tree. The airplane remained suspended in the pine tree until rescue personnel arrived. The FAA inspector stated that both wing fuel tanks were not compromised in the accident. No evidence of fuel was found in either tank. An examination of the airframe and engine did not reveal evidence of preimpact mechanical deficiencies. The FAA inspector stated that the pilot told him that she may have exhausted the airplane's fuel supply during the flight. The student pilot further stated to the inspector that she used 4 gallons per hour as a standard figure for flight planning purposes. She did not consider fuel consumption for taxi and takeoffs, or make reference to the fuel consumption charts found in the airplane flight manual. An examination of the student pilot's cross country endorsement (attached) revealed that she had been authorized by her flight instructor to fly from Bountiful, Utah, to Milford, Utah, via West Jordon, Utah, and Nephi, Utah on the morning of the accident. The student pilot, however, decided to deviate from this plan. After departing from Bountiful, she landed in West Jordon, then departed for Milford. She flew over Milford and then headed for Fillmore, Utah. She had decided to land at Fillmore because she was told by a friend that fuel was inexpensive there. Upon landing at Fillmore, she took on 4 gallons of fuel (receipt attached). She told the FAA inspector that she only took on 4 gallons because she had very little cash on hand. The cost of the 4 gallons ultimately exceeded the cash she had on hand, so she paid with a credit card and was embarrassed to take on more fuel. After departing from Fillmore, she headed back to Bountiful. The engine lost power en route near Salt Lake City. According to the FAA inspector, the flight instructor stated that he was unaware of the student pilot's deviation from the endorsed flight plan.