Evaluation location: Kentucky, United States
The main study site was an open, grassy area on Maury silt loam soil on the University of Kentucky campus in Lexington, Kentucky, adjacent to the Arboretum and State Botanical Garden of Kentucky (N38°1’; W84°30’; elevation 302 m). Five replicates of each elm accession were planted in a randomized complete block in rows spaced 7.6 m apart, with 7.6 m between trees within rows and 50 m between replicates. Trees were planted in spring 2005 or 2006. The trees were obtained from nurseries as bare-root transplants and ranged from 1.5–2.4 m height at time of planting. They were staked, watered as needed, and mulched over grass that had been killed with glyphosate herbicide. Twenty fully expanded leaves were collected from each tree in early June 2009 and measured with an electronic area meter (Li-Cor, Lincoln, NE) as square centimeters.