On August 20, 1999, at 1700 eastern standard time, a Cessna 150L, N161BA, collided with a tree and a pond during takeoff from the Shenk Airstrip, Garrett, Indiana. The private pilot and the sole passenger received minor injuries. The airplane was substantially damaged. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The flight was originating at the time of the accident. The pilot reported he flew to the Shenk Airstrip to practice a short/soft field takeoff. He reported they landed on runway 09 (1,500' x 141') and taxied back to takeoff on runway 09. He reported that during the takeoff he noticed the treeline approaching quicker then usual. He reported, "To clear the trees, I placed the aircraft in the steepest climb possible without stalling." He reported the leaves of the trees brushed the landing gear and seconds later he heard a loud impact under the right wing. He reported the airplane pivoted down and to the right, descending in a steep nose down attitude until it contacted the pond. The airplane came to rest in 10' to 12' of water. The pilot and passenger evacuated the airplane. The passenger reported seeing an "X" on the end of the airstrip prior to takeoff; however, he did not mention it to the pilot. He reported the pilot held the brakes at the end of the runway and advanced the power to 2,700 rpm. He reported the flaps were extended 10 degrees. He reported the takeoff roll was "bumpy" and the airplane did not accelerate as quickly as it had during their previous takeoff on a paved runway. The passenger reported the pilot pulled back on the yoke and the stall warning was coming on intermittently. He reported the pilot kept increasing the angle of attack as they approached the trees. The passenger reported the airplane contacted the trees and descended into the pond. Inspectors from the Federal Aviation Administration (FAA) South Bend, Indiana, Flight Standards District Office reported the right wing of the airplane contact a 50' tall tree located approximately 800' from the end of the airstrip. The airplane traveled an additional 300' before coming to rest in the pond. They reported that at one time the airstrip was approximately 2,000' long; however, the airstrip had been shortened to approximately 1,500' when corn was planted. The west end of the airstrip was marked with a yellow-black striped "X" and the east end of the airstrip was marked with a white "X" to signify that the airstrip was closed. The grass on the airstrip was approximately 4 to 6 inches high. The pilot reported he had flown into the airstrip in the past when the length was 2,000'. He was unaware that the airstrip had been shortened and closed. The Indiana Aeronautical Chart indicates the length of the airstrip is 2,000'. The Chicago Sectional Aeronautical Chart, 58th Edition, May 20, 1999, indicated the airstrip was open and the airstrip length was 2,000'. According to the FAA, in early May, 1999, the airstrip owner informed the Terre Haute Flight Service Station that the length of the airstrip was shortened to 1,500' and the airstrip was permanently closed. The FAA inspector stated that it was too late to have the airport removed from the Sectional Aeronautical Chart 58th Edition, but it would be removed from the next edition. The Terre Haute Flight Service Station (FSS) stated that the airstrip identifier had been removed from their computer system and Shenk Field was not longer in the Airport Facility Directory. The FSS reported that they do not issue Notices to Airmen (NOTAMs) regarding issues involving private airstrips.