On March 30, 1995, at 0700 central standard time, a Piper PA-25-235, N4900Y, was destroyed while maneuvering near Catoosa, Oklahoma. The commercial pilot sustained minor injuries. Visual meteorological conditions prevailed for the instructional flight. During an interview, conducted by a Federal Aviation Administration (FAA) inspector, the flight instructor reported that the hopper was loaded with water and the aerial application student was practicing swaths over the trees. The instructor, who was maintaining radio contact with the pilot and observing the airplane from the ground, observed the airplane's wheels contact the trees as the pilot completed a turn around maneuver. Subsequently, the airplane decelerated as it descended through trees for 310 feet before coming to rest in a nose down vertical position. Examination of the airplane by a FAA inspector revealed no mechanical or structural anomalies. Both wings and fuselage were structurally damaged. Repeated attempts to obtain a completed Pilot/Operator Report, NTSB Form 6120.1/2, were unsuccessful.