1. School of Forest Resources, University of Maine, Orono, ME 04469, USA
2. Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT 05405, USA
3. Minnesota Department of Natural Resources, St. Paul, MN 55106, USA
4. Cloquet Forestry Center, University of Minnesota, Cloquet, MN 55720, USA
5. USDA Forest Service, Northern Research Station, Grand Rapids, MN 55744, USA