During ridge soaring operations, areas of sink were encountered and the aircraft descended over forested terrain. The only area suitable for an outlanding was a small deer enclosure. The pilot initially overshot the area and during the turn to re-position the aircraft for landing the right wing struck the fence surrounding the enclosure. The aircraft yawed through 90 degrees before impacting the ground in a level attitude. Although general soaring conditions were poor, the pilot had elected to leave the ridge-line to conduct a sight seeing flight. During this flight a wind change moved through the area. On return to the ridge-line the pilot, who had not detected the wind change, persisted with efforts to find an area of lift. The proximity of the aircraft to the tops of the trees and the small size of the deer enclosure precluded the pilot sighting the clearing in time to conduct a straight-in approach.