The pilot of the glider had located five possible locations for off airport landings in advance of the glider flying event. On the accident flight, after receiving an aerotow, he maneuvered in the local area and found thermal lift that he used to climb further. After finding additional lift, the pilot flew across a ridge line toward a mountain where he hoped to find additional lift but was unsuccessful. He then turned around attempted to cross back over the ridge line where he knew there were several sites for an off-airport landing. The pilot realized that he would not be able to cross the ridge and then observed a private turf runway that he had not previously seen. During his landing approach the glider struck trees about 200 ft short of the runway, resulting in substantial damage to its fuselage and wings. The pilot reported that there were no preimpact mechanical malfunctions or failures of the glider that would have precluded normal operation.