1. Department of Natural Resources, University of New Hampshire, Durham, NH 03824, USA.
2. Risk Assessment and Residue Division, Food Safety Inspection Service, USDA, 2150 Centre Avenue, Building B, Mail Stop 2E7, Fort Collins, CO 80526, USA.
3. USDA Forest Service, Northeastern Research Station, P.O. Box 640, Durham, NH 03824, USA.