Ecological and Topographic Features of Volcanic Ash-Influenced Forest Soils

Abstract

Volcanic ash distribution and thickness were determined for a forested region of north-central Idaho. Mean ash thickness and multiple linear regression analyses were used to model the effect of environmental variables on ash thickness. Slope and slope curvature relationships with volcanic ash thickness varied on a local spatial scale across the study area. Ash distribution and aspect showed weak correlation. Elevation and ecologically based plant associations accounted for about 54 percent of the observed variation in volcanic ash thickness. Climax plant associations moister than grand fir/queen cup beadlily (Abies grandis/Clintonia uniflora) had consistently thick ash mantles and soils that would be classified as either Andisols or andic subgroups using Soil Taxonomy. The statistical model error of 10.7 cm was significantly lower than the >20 cm variation often found in local soil series. This model quantitatively assesses ash distribution and can be integrated into other local ecological models.

Parent Publication

• Volcanic-ash-derived forest soils of the inland Northwest: Properties and implications for management and restoration

Citation

Kimsey, Mark; Gardner, Brian; Busacca, Alan. 2007. Ecological and Topographic Features of Volcanic Ash-Influenced Forest Soils. In: Page-Dumroese, Deborah; Miller, Richard; Mital, Jim; McDaniel, Paul; Miller, Dan, tech. eds. 2007. Volcanic-Ash-Derived Forest Soils of the Inland Northwest: Properties and Implications for Management and Restoration. 9-10 November 2005; Coeur d’Alene, ID. Proceedings RMRS-P-44; Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 7-21