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Restoring American Elms to their Native Range

[photo:] Researchers check tree saplings on Army Corp of Engineers land.The American Elm tree was once widely distributed in the Eastern United States and was preferred for planting along city streets and in the yards of many homeowners.  The Dutch Elm Disease (DED) fungal pathogen (Ophiostoma ulmi) was introduced into the United States in 1930.  In subsequent years the disease destroyed millions of American elm trees all over the United States and Canada.  One line of research on American elms that began in the 1970s and continues today is focused on identification of American elm cutivars that could withstand the DED fungal pathogen. 

In 2003, the Northern Research Station (NRS) initiated the American Elm Restoration Project to restore the American Elm in the state of Ohio.  The effort to plant tolerant strains of elm trees in parks and wild forests in Ohio was made possible with assistance from the Ohio Department of Natural Resources Division of Forestry, Franklin County Metro Parks, and The Wilds.  In subsequent years, the restoration effort has spread to Iowa, Wisconsin, Minnesota, Vermont, New Hampshire, Massachusetts, Connecticut, Kentucky, West Virginia, Pennsylvania, Virginia, Tennessee, and Alabama through partnerships.  


The Forest Service has partnered with many organizations over the years to make the American Elm Restoration Project a success.

Acres of Forest Affected

Three NRS Scientists and two Biological Sciences Technicians

Base Annual Budget
(180,000 salaries, 20,000 supplies, travel, etc.)



The American Elm Restoration project that began in Ohio in 2003, expanded in 2005 to include establishment of restoration sites in Iowa, Wisconsin and Minnesota with the help of additional partners.  In 2007 additional plantings were made in Wisconsin to test cold hardiness.  In 2010 -2013, plantings of DED tolerant elms were made in Vermont with assistance from the Nature Conservancy.  To date, 30 experimental American elm restoration sites have been established.  In addition, American elm seedlings originating from the NRS elm orchard were used in operational restoration efforts along the Mississippi River in Minnesota, Wisconsin, and Iowa, and in Kenticky, West Virginia, Pennsylvania, Virginia, Tennessee,  and Alabama in the Appalachian Regional Reforestation Initiative.

Today NRS scientists, collaborating with Midwest and Northeast research partners and land management agencies are breeding disease-tolerant varieties of the American elm for outplanting in parks and wild landscapes throughout the region.  (To date, no elms that are completely resistant to DED have been identified.)  In addition, work is continuing to screen large (3-4 feet DBH) survivor American elms for tolerance/resistance to DED to increase the genetic base of tolerant elms.


Partners have been critical to testing these DED tolerant elm seedlings in various habitats, planting 3,500 trees in 8 states. These trees will thrive and spread their pollen, carrying resistant genes into the wild populations. Some of these elms were planted on Earth Day 2013 at the Flight 93 National Memorial near Shanksville, Pennsylvania.

Lessons Learned

Parnerships have enabled the Northern Research Station to greatly expand the original American elm Restoration Project effort from one state to fourteen states.  Not only does this increase geographic span of the effort, but also increases the potential for increasing genetic diversity in the pool of tolerant elm cultivars. 

Partner Organizations

Last Modified: July 31, 2019