1. Department of Natural Resources, Cornell University, 209 Bruckner Hall, Ithaca, NY 14853, USA
2. Hardwood Tree Improvement and Regeneration Center, Department of Forestry and Natural Resources, Purdue University, 715 W. State Street, West Lafayette, IN 47907, USA
3. Southwick Associates, P.O. Box 6435, Fernandina Beach, FL 32035, USA