According to the pilot, he configured the flaps to 20° while he waited for the aerial application airplane to take on 50 gallons of fuel and 400 pounds of fertilizer. He taxied onto the 2,600 ft long asphalt runway, for his 4th aerial application flight of the day. The pilot applied brakes and full power before he released the brakes to initiate the takeoff roll. About 1,300 ft down the runway, the airplane remained on the ground. The pilot applied back pressure to the control stick and the airplane ascended about 10 feet above ground level. The airplane would not climb, and the pilot applied full flaps. The airplane subsequently settled back onto the remaining 1/3rd of the runway. The pilot reported that he did not observe any cockpit instrument cautions or warnings illuminated. The airplane overran the departure end of the runway and collided with trees. The manufacturer’s airplane flight manual (AFM) contains a warning that stated, when taking off from a short-field runway, full flaps should not be used during the takeoff sequence. The use of full flaps creates large amounts of drag, lengthens the ground roll, and impairs climb performance. The pilot submitted an NTSB Form 6120.1, Pilot Aircraft Accident Report, but did not include pages 9 and 10, which encompassed the pilot’s narrative, and his assertion regarding a mechanical malfunction during the sequence of events.