NTSB Factual Report

After approximately 2 hours of cross-country soaring, the pilot headed back toward the departure airport. Unable to find adequate thermal lift, the pilot altered course toward a group of gliders who had encountered thermals. Finding no source of lift near the other gliders, and unable to reach the airport, he chose an open field for a forced landing. During the landing approach, the pilot executed an "S-turn" with the flaps fully extended and with steep bank angles, which resulted in a "faster than expected" altitude loss. The glider struck trees bordering the intended landing field, resulting in substantial damage.

NTSB Probable Cause

The pilot's failure to maintain altitude/clearance from trees along his final approach path.