Big South Fork Trail Keeper Program Needs Volunteers for 2019. The Trail Keeper program is a volunteer partnership for people who love the park’s trails and want to help take care of them. Trail keepers are expected to hike, bike or horse ride their adopted trail at least four times during the calendar year. They also report on overall trail conditions, pick up any trash, and submit a trail report after each visit. Trail Keepers are a valuable asset to the park staff. To learn more about the Big South Fork Trail Keeper program, email the park’s volunteer coordinator at effie_houston@nps.gov or call (423) 569-9778.