The airplane took off to the northeast and was performing normally, according to the pilot. The pilot remained in ground effect until reaching the top of the hill (at the northeast end of the runway), at which point the airplane failed to clear a tree line approximately 100 yards off the end of the runway. The airplane impacted the trees at an altitude of 15~20ft agl. The last 1,000ft of the runway slopes upward. The engine was test run under the supervision of the FAA, and it operated satisfactory.