Dutch elm disease (DED) is one of the most commonly known and destructive tree diseases in the world. The disease was first observed in Ohio in 1930, and by 1976, only 34 million of the estimated 77 million elms present in U.S. urban locations remained. Research on American elm from the 1970s to the present has focused in large part on the identification of American elm individuals that can withstand the DED pathogen. To increase American elm’s long-term recovery as a canopy tree, it is crucial to increase the genetic variation of tolerant elms available for planting in urban and rural settings. Related Research: Restoring American Elms to their Native Range (NRS) “New American Elms Restore Stately Trees” (1996) “Evaluation of 19 American Elm Clones for Tolerance to Dutch Elm Disease” (2005) “Proceedings of the American Elm Restoration Workshop” (2016) “Development of New Dutch Elm Disease-Tolerant Selections for Restoration of the American Elm in Urban and Forested Landscapes” (2017) Scientists:  Jennifer Koch, Research Biologist, Northern Research Station, Delaware, Ohio Kathleen Knight, Research Ecologist, Northern Research Station, Delaware, Ohio Denny Townsend, Research Geneticist (Retired), USDA ARS, ​​U.S. National Arboretum, Washington, D.C. Dale Lesser, Farmer, Lesser Farms and Orchard, Dexter, Michigan  Produced by the USDA Forest Service Northern Research Station.  Want more information? Visit us at www.nrs.fs.fed.us/podcast/2/4/  Any questions? Connect with us on Twitter!