At 1445 central time, a Piper Cherokee 140 struck a line of trees 400 feet from the departure end of runway 18 at El Dorado Springs Memorial Airport. The airplane landed on runway 18 and backtaxied to the intersection of runway 4-22 before initiating the takeoff run. Approximately 1,830 feet was available from the intersection. The pilot suffered minor injuries and the passenger sustained serious injuries.