Northern Prairie Wildlife Research Center
Camp Ripley is a 21,400-ha parcel on the prairie-forest transition zone in central Minnesota. The terrain in this area is generally flat, and the major cover is northern hardwood forest (primarily oak [Quercus spp.], aspen [Populus spp.], and birch [Betula spp.]) interspersed with large open areas (grasslands, wetlands, and military firing ranges) comprising about 45% of the total (Brezinka 1995). Deciduous trees were without leaves during data collection. Temperatures ranged from -22 to 9°C.
The Alaska study area lies just north of Mount McKinley in Denali National Park and Preserve, including the foothills of Mount McKinley as well as spruce bogs, open eskers, riverbottoms, and tundra flats (Mech et al. 1998). Temperatures during the study varied from -7 to 23° C.
The Superior National Forest study site is gently rolling, and the vegetation is a mixture of maturing forests, various aged conifer plantations and clear-cuts. Aspen (Populus spp.), paper birch (Betula papyrifera), balsam fir (Abies balsamea), red pine (Pinus resinosa), and jack pine (Pinus banksiana) predominate in the uplands. White and black spruce (Picea glauca and Picea mariana) dominate the lowlands (Mech and Gese 1992). Temperatures in the Superior National Forest area were -17° C to 20° C during the study, and deciduous trees were leafless for some of the tests and fully leafed for others.