1. Anchorage Forestry Sciences Lab, PNW Research Station, USDA Forest Service, 161 E 1st Avenue, Anchorage, AK 99501, USA.
2. Department of Forest Ecosystems and Society, Oregon State University, 321 Richardson Hall, Corvallis, OR 97331, USA.
3. College of Agricultural Sciences, Oregon State University, 126 Strand Agriculture Hall, Corvallis, OR 97331, USA.
4. Oregon State University, 1500 SW Jefferson Way, Corvallis, OR 97331, USA.