The vegetation is typical of much of interior Alaska. Upland vegetation is boreal forest taiga consisting primarily of black spruce (Picea mariana) in wet and poorly drained areas and white spruce (P. glauca) on drier sites. Quaking aspen (Populus tremuloides) commonly occurs on well drained south facing slopes, and along with paper birch (Betula papyrifera) often occur in recently burned or disturbed areas. Balsam poplar (P. balsamifera) is common along water courses. As elevation increases, dense spruce gives way to open spruce woodlands mixed with tall shrubs, then dwarf-shrub communities, and finally alpine tundra. Shrubs are most common along streams and water bodies, within recently burned areas, and along gullies that drain subalpine tundra. The shrub component is primarily willow (Salix spp.), alder (Alnus spp.), and dwarf birch (B. spp.).
The major forces shaping the diversity of habitat on the Refuge are fire, flooding and insects, all of which interact in a complex way. The interior Alaska boreal forest eco-region, which encompasses the Refuge, is fire-adapted.