Join us in the Presidio's Tennessee Hollow Watershed for a BIG day of stewardship with our friends at REI. Volunteers are needed to help plant and water native plants, remove invasive species, take care of trees, and improve landscaping in and around El Polin Spring. A long-term effort is underway to revitalize the Tennessee Hollow Watershed. Come learn about its extraordinary natural and human history while being a part of this ambitious long-term restoration effort. All ages welcome. Registration is required. To sign-up, click here.