Fire and vegetation type effects on soil hydrophobicity and infiltration in the sagebrush-steppe: II. Hyperspectral analysis

Hyperspectral remote sensing methods were developed to identify and differentiate post-fire characteristics in burned sagebrush-steppe. This shrub-steppe environment is typical of the Intermountain West, where wildfire intervals are frequent. After a 78,000 ha wildfire in 2005 in southern Idaho, soil water repellency and fire severity were evaluated with field and airborne spectroscopy measurements. A hyperspectral analysis correctly identified bare ground, low and high fire severity grass areas and low fire severity shrub areas, with accuracies between 74 and 92%. The differentiation of moderate and high fire severity areas was ambiguous, resulting in accuracies between 39 and 54%. The hyperspectral analysis of soil water repellency resulted in a representative map of its distribution with an accuracy of 65%. The analysis techniques conducted in this project signify spectroscopy to be beneficial for differentiating soil characteristics and fire severity classes in burned shrub-steppe areas, where the mostly bare, spectrally homogenous soils exhibit subtle but significant changes in reflectance. The spatial representation of post-fire soil and vegetation conditions may provide a better understanding of post-fire vegetation and surficial processes (water and wind erosion) in shrub-steppe.