According to the pilot, the glider was towed to an altitude of 4,700 feet above mean sea level and released. Shortly after release, the pilot encountered severe turbulence that caused the glider to become inverted. During the turbulence encounter, the pilot's head impacted the canopy several times, and shattered the canopy. While the glider was inverted the pilot heard "cracking in the wings." After recovering from the turbulence upset, the pilot attempted to land in a field. While on the final leg of the approach, the glider impacted some trees, and a hard landing resulted. The tree strikes and hard landing caused substantial damage to the wing and fuselage.