1. Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
2. US Forest Service Northern Research Station, St. Paul, MN, USA
3. Department of Forestry, Michigan State University, East Lansing, MI, USA
4. Department of Forest Resources and Environmental Conversation, Virginia Polytechnic Institute, Blacksburg, VA, USA
5. School of Forest Resources, University of Maine, Orono, ME, USA