Work has started on more than 20 miles of hiking and horse trails at Don Carter State Park in North Hall. The new trails could open by early spring, “but that’s dependent on a lot of factors,” including weather, said Steven Emery, assistant park manager. The project, which cost $450,000 to $500,000, involves construction of some nine miles of hiking trails, which will add to the 3 ½ miles already in place, and 12 ½ miles of horse trails, Emery said.