After a glider flight of approximately one hour, the 4,674-hour commercial pilot was on final approach to land to the 3,638-foot long by 300-foot wide grass/turf runway. While on short final, the single-seat composite glider encountered "severe sink" and the left wingtip impacted a tree. The glider "cartwheeled" and came to rest in the upright position on the approach end of the runway 25. The pilot was extricated by rescue personnel, who later reported his injuries as minor. No mechanical anomalies were reported with the airplane's flight controls. The pilot reported having accumulated 10 hours in the same make and model, with a total of 31.6 hours in gliders. The reported wind at the nearest airport with a weather reporting station, located about 35 nautical miles north of the accident site, were reported from 220 degrees at 5 knots, gusting to 12 knots. The pilot recommended that glider pilots use an "aim point" at least 800 feet further down the runway when landing in the future.