1. a US Forest Service, Northern Research Station , 202 Natural Resources Building, Columbia, MO, 65211, USA
2. b US Forest Service, Southern Research Station , PO Box 227, Stoneville, MS, 38776-0227, USA
3. c US Forest Service, Southern Research Station , 320 Green Street, Athens, GA, 30602, USA
4. d Hardwood Tree Improvement and Regeneration Center, Department of Forestry and Natural Resources , Purdue University , West Lafayette, IN, 47907-2061, USA