On January 15, 2006, about 1430 eastern standard time, a Schweizer SGS 2-33 glider, N5728S, registered to High Soaring Inc., and operated by a private individual as a Title 14 CFR Part 91 personal flight, made a hard landing in Immokalee, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The commercial-rated pilot was not injured, and the glider incurred substantial damage. the flight originated the same day in Immokalee, Florida, about 1345. The pilot said that after being towed to 3,000 feet and having an uneventful initial part of the flight, he returned to Immokalee Airport, and noted that given the direction of the winds, it would be safer for him to make an off airport landing in a nearby field. The pilot said that during the landing he clipped the top of pine trees which then impacted wires, and he landed the glider hard in the field beyond. In addition, the pilot said that upon landing the field was rough and uneven, and as a result glider incurred substantial damage to its skid, and tail-wheel area.