Suzanne Johnson, Volunteer Archivist and Exhibits Curator at Fairfield County Museum, left, and the museum’s Executive Director Pelham Lyles measure the circumference of a giant willow oak on private property off Peays Road in Winnsboro. With an 18 foot, one and a half inch circumference, the tree comes close to the tree in the state with the largest circumference of 22 feet.  Circumference is just one category in which trees are rated for size. Museum staff is currently researching whether the willow oak’s height and branch spread might qualify it as the largest tree in South Carolina.