Shortly after takeoff the non-certificated pilot lost control of the amphibious airplane and impacted trees and subsequently the ground. The airplane came to rest in an upright position and the pilot was able to exit unassisted. The airplane’s wings and fuselage sustained structural damage. The pilot reported that a gust of wind had impacted the side of the airplane during takeoff and that he was unable to keep it out of the trees. The pilot further reported that there were no malfunctions or failures with the airplane’s flight controls or engine.