On July 2, 1998, at 2020 central daylight time, a Piper PA-28-140 airplane, N1656J, was substantially damaged upon collision with trees and terrain while on initial takeoff climb from the Tulsa Downtown Airpark near Tulsa, Oklahoma. The flight instructor sustained minor injuries and the student pilot was seriously injured. The airplane was owned and operated by the student pilot under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local training flight for which a flight plan was not filed. The flight was originating at the time of the accident. According to the flight instructor, the purpose of the flight was to review flight maneuvers prior to the student's flight test for the private pilot certificate which was scheduled for July 6. The flight instructor stated that "the magnetos and the static RPM checks were found to be normal" during the engine runup. He added that the airplane was within weight and balance limits with 30 gallons of fuel onboard. The flight instructor reported that the airplane "was configured with 25 degrees of flaps for a simulated short field takeoff" from runway 20. The flight instructor added that "the engine sounded smooth during the entire flight" and the airplane appeared to accelerate normally as it became airborne by the 2,000 foot marker of the 2,965 foot long runway. After breaking ground, the 66 hour student pilot established the airplane at the best angle of climb speed; however, the airplane's climb performance was degraded to the point that the airplane was only climbing at a rate of 100 feet per minute. The flight instructor assumed control of the airplane and initially managed to maneuver the airplane toward the west, around the rising terrain and obstructions at the departure end of the runway. The flight instructor added that "when the impact was inevitable, he reduced the power and lowered the flaps in order to impact at the slowest possible speed." He added that the 1967 model airplane was not equipped with shoulder harnesses for any of the occupants. Examination of the wreckage by a FAA inspector revealed that the nose landing gear folded aft and both main landing gear were pushed aft. The engine firewall and underside of the fuselage sustained structural damage. According to the maintenance records for the airplane, the Lycoming O-320-E2A engine, serial number L-22017-27 had accumulated a total of 129 hours since its last major overhaul. The engine was examined on August 27, 1998, under the supervision of the FAA inspector. The damaged propeller was removed and a test propeller installed. The engine was started and operated through the normal flight parameters. No pre-existing engine deficiencies were noted and the investigation did not reveal any evidence that the engine was not capable of operating and producing power prior to the accident. A copy of the report for the engine examination is enclosed. There was no reported convective activity within 50 nautical miles of the airport. The winds at the Tulsa International Airport were reported from 180 degrees at 9 knots. The IIC calculated the density altitude at 2,109 feet.