1. Department of Wildland Resources and Ecology Center, Utah State University , 5230 Old Main Hill, Logan, UT 84322
2. School of Forestry, Northern Arizona University , PO Box 15018, Flagstaff, AZ 86011 , USA
3. Department of Forest Resources, University of Minnesota , 1530 Cleveland Ave. N., St. Paul, MN 55108 , USA
4. Center for Forest Nursery and Seedling Research, College of Natural Resources, University of Idaho , 875 Perimeter Dr., Moscow, ID 83844 , USA
5. USDA Forest Service, Coconino National Forest , 4373 S. Lake Mary Road, Flagstaff, AZ 86005 , USA