Denali Soils Inventory
Ice Wedge, Denali
Denali Soil Subsections Map (515Kb pdf)
Soil survey and ecological site information provides a stable baseline to make land use decisions and better understand park resources. Five physiographic sections are recognized in Denali National Park and Preserve, each with unique soils and landscapes. South of the crest of the Alaska Range and lying within the humid temperate climate zone are two physiographic sections: the Alaska Range-Southcentral Mountains Section and Cook Inlet Section. Major soil orders include the spodosols (soils with well expressed soil horizons), the andisols (soils formed in weathered volcanic ash), and the inceptisols (soils with moderately well expressed horizons). Volcanic ash influences the surface layers of most area soils and has unique properties including low bulk density, high water-holding capacity, and acidic pH levels. Soils in lowlands support mixed forest types, with mountains dominated by extensive alder scrub, willow scrub, herbaceous meadow, and dwarf ericaceous scrub communities.
North of the Alaska Range crest and lying within the polar climate zone are three physiographic sections: the Alaska Range-Interior Mountains, the Kuskokwim Plain, and the Kuskokwim Mountains. Periglacial features (micro-relief formed by frost action) and permafrost are common to these sections. Soils with permafrost (gelisols) occupy most lowlands, formed in loamy loess, colluvium, drift or alluvium; and have dwarf needle-leaf woodlands. Inceptisols are found in mountains, formed in colluvium, and have scrub and dwarf scrub types.
Reaction in mountain soils depends on parent material rock type with calcareous soils on shale and limestone and acidic soils on diorite and schist. The Kuskokwim Plain Section, which occupies about 30 percent of the Park, contains the largest contiguous area of permafrost (gelisols), as well as wetlands. Gravelly and loamy alluvial soils (entisols) occupy flood plains throughout the Park. These weakly formed, neutral to mildly calcareous soils have a multitude of scrub, wet meadow, and forested communities, depending on local drainage condition and flooding disturbance.