Affiliation: | a USDA Forest Service, Northern Research Station, 201 Holdsworth Hall, University of Massachusetts Amherst, Amherst, MA 01003, USA b USDA Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA c USDA Forest Service, Northern Research Station, P.O. Box 480, Bartlett, NH 03812, USA |