aaw_040 December 20, 2018February 5, 2019 Matthew Caulkins, Web Applications Program Manager Previous Next M-61. Ulmus americana Connecticut (Wethersfield). The Wethersfield Elm, Largest Elm in the United States. Girth of trunk 28 ft. Photograph by E.H. Wilson, May 4, 1924. All photographs by Ernest Henry Wilson. Copyright © President and Fellows of Harvard College, Arnold Arboretum Archives; all rights reserved.