The Challis Field Office region is one of the driest areas in Idaho, receiving only seven inches of rain per year. The region’s dry climate and its ashy and volcanic soils support diverse and unique plant species and associations. The lands managed by the Challis Field Office lie within the Northern Rocky Mountains and host the following range of vegetation types.
Low-elevation Shrub (sagebrush steppe) is the dominant vegetation type. Depending on soil conditions, elevation and aspect, shrub steppe systems can be classified into several major vegetation associations. Vegetation varies from grasslands to sagebrush steppe in broad valleys, to mountain shrub in the in the steeper river canyons, to coniferous forest in the higher elevations.
The Upland Vegetation type includes sagebrush steppe, Western ponderosa forest, grand fir/Douglas fir forest and Western spruce/fir forest. Whitebark pine and limber pine are also abundant at higher elevations.
The Riparian/Wetland Vegetation type is also present in this area. Riparian zones within the Challis Field Office can generally be identified by the existence of riparian-dependant vegetation such as aspens, cottonwoods, willows, sedges and rushes.