According to the glider pilot, about 15 minutes into the flight, the glider had ascended to 2,000ft AGL, but he was unable to find more lift. The glider was about 1.5 miles west of the airfield, and he decided to continue west in search of lift under a cloud formation. He did not find lift and returned to his previous position 1.5 miles west of the airfield, but his altitude was 1,200ft AGL. The pilot decided to land off the airfield. The pilot entered the pattern using the glider's spoilers and turned from downwind to base at 700ft AGL. He reported that he allowed the glider's flight path to take him .5 miles too far downwind. He attributed his miscalculation to his fascination with the altimeter, instead of flying the glider. During the base leg of the pattern, he reported that he had to, "crab the airplane into the wind" to avoid being pushed further downwind. On final the glider encountered a headwind, descended rapidly and collided with trees. The glider sustained substantial damage to the left wing spar. The pilot reported that the wind at the time of the accident was from 190° at 15 knots. He attempted to land on a heading of 170°. The pilot reported that there were no mechanical malfunctions or failures with the glider that would have precluded normal operation.