National Elm Trial

The National Elm Trial is an American volunteer effort to evaluate a range of newly developed elm cultivars as replacements for elms destroyed by Dutch elm disease (DED). It is coordinated by Colorado State University.

The trial began in 2005, but has been restricted to elm cultivars commercially available in the United States, unlike the trial conducted by Iowa State University in the 1970s which included the most recent European developments. The trial will be conducted for 10 years, with annual assessments of each tree for height, diameter, crown characteristics, and fall color, as well as response to vascular diseases, canker diseases, foliar diseases, insect infestations, bark beetle infestations, and abiotic damages. Stated goals of the trial are as follows:

• Determine the growth and horticultural performance of commercially available DED-resistant elm cultivars in various climate regimes in the United States.
• Determine the relative disease, insect, and abiotic stress tolerance of these cultivars.
• Promote the propagation and use of elms through local, regional, and national reporting of the trial results to wholesale tree propagators and growers, retail nursery and garden center operators, landscaper designers, arborists, and the general public.

As of January 2000, 19 distinct cultivars are being evaluated in regional trials taking place under the scientific supervision of Auburn University, University of California at Davis, Colorado State University, Purdue University, Iowa State University, Kansas State University, Michigan State University, University of Minnesota, Rutgers University, State University of New York, North Dakota State University, Ohio State University, Utah State University, University of Vermont, Washington State University, and West Virginia University.