Large &minus Scale Digital Soil Mapping in a Rugged Oregonian Wilderness.

The Eagle Cap wilderness is Oregon’s largest wilderness area. The wilderness is 146,000 ha (361,000 ac.) of rugged mountains comprised of diverse lithologies, geomorphic histories, and large climatologic gradients. From a digital soil mapping perspective (DSM) wilderness areas pose significant challenges because of very limited data, though when available, is generally not representative of the soils in the wilderness; the Eagle Caps being no exception. Using fuzzy classification, remote sensing, and geomorphometric covariates, we developed a map of soil probability over the entire wilderness using no training data. The resulting map is a fuzzy likelihood of soil occurrence and which correlates with soil depth. Detailed and targeted fieldwork is used to determine soil types which occur in map units, as defined a priori. This method has proved relatively fast and methodologic interpretation is straight forward. This approach adds to the growing toolbox for producing soil maps in areas which are not slated for official survey, yet where soils information is needed.