The pilot of the Christen Eagle II said he was "lined up well," for the runway but just prior to landing, the left wing struck trees, and the airplane impacted the ground near the runway threshold. The airplane came to rest inverted, and even though it was upside down, and the pilot had difficulty releasing the canopy, he was able to exit the airplane unassisted. Photographic evidence indicated that the trees were located approximately 80 feet prior to the threshold, with tops approximately 20 feet above the runway elevation. The runway threshold was not displaced, and the presence of the trees was not included in the commercially available obstacle notation.