[1] Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University College of Natural Resources, Virginia Tech, 310 West Campus Dr., Blacksburg,VA,24061, United States
[2] Harley Langdale Jr. Center for Forest Business, Warnell School of Forestry and Natural Resources, Unversity of Georgia, 180 E. Green Street, Athens,GA,30602, United States
[3] Virginia Polytechnic Institute and State University, Blacksburg,VA, United States