The pilot elected to conduct a soft field takeoff due to rough irregularities in the runway. After fully extending the flaps the pilot initiated the takeoff run, and the airplane became airborne within 200 to 300 feet. The pilot had difficulty keeping the airplane's pitch attitude low, and upon reaching tree height the airplane stalled. The airplane then began to descend and rolled to the left. The pilot was unable to arrest the descent, the airplane impacted the ground, and was subsequently consumed by a post-impact fire.