On June 11, 2005, about 1530 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N5408Y, sustained structural damage as a result of an in-flight collision with trees during takeoff from a private airstrip, located about 3 miles northeast of Palmer, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight under Title 14, CFR Part 91, when the accident occurred. The student pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated about 1530, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on June 13, the pilot reported that he had recently removed the airplane's skis and reinstalled tundra tires. He said that after adding hydraulic fluid to the airplane's brake system, he boarded the airplane, locked the airplane's brakes, and started the engine. He noted that at that time he had no intention of flying. The pilot reported that he momentarily looked down at the instrument panel, and suddenly noted that the airplane was moving downhill on the taxiway. He said that he was unable to stop the airplane so he elected to apply full engine power in an attempt to fly. The airplane initially became airborne, but settled into a stand of small birch trees at the end of the taxiway. The pilot added that a quartering tailwind contributed to the accident. The airplane received structural damage to both wings and the fuselage. According to the NTSB Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the pilot, there were no preaccident mechanical anomalies noted with the airplane. However, the pilot noted, in part, in the safety recommendation (How Could This Accident Have Been Prevented?) section of the NTSB report, "Bleed brakes after every ski/wheel changeover."