The Colorado State University College of Agricultural Sciences coordinated the trial.
[1] The trial began in 2005, but was 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 was 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.
[2] Based on the trial's final ratings, the preferred cultivars of the American elm (Ulmus americana) are ‘New Harmony’ and ‘Princeton’.
The preferred cultivars of Asian elms are the Morton Arboretum introductions and ‘New Horizon’.