April Ulery
Ph.D. 1992
Dissertation title:
- Forest Fire Effects on Soil Morphology and Mineralogy
Currently:
- Associate Professor of Soil Chemistry, New Mexico State University
- http://aghort.nmsu.edu/Faculty/ulery.htm
Publications from dissertation research:
- Ulery, A.L., and R.C. Graham. 1993. Forest fire effects on soil color and texture. Soil Sci. Soc. Am. J. 57:135-140.
- Ulery, A.L., R.C. Graham, and C. Amrhein. 1993. Wood-ash composition and soil pH following intense burning. Soil Sci. 156:358-364.
- Ulery, A.L., R.C. Graham, and L.H. Bowen. 1996. Forest fire effects on soil phyllosilicates in California. Soil Sci. Soc. Am. J. 60:309-315.
Wildfires occur commonly throughout the western United States.
Their effects on vegetation and ecological succession are widely recognized, but less is known about how fire affects the physical, chemical, and mineralogical properties of soils. April sampled soils from intensely burned forest sites throughout California.
Severe burning occurred where fuel was concentrated, such as under burned logs, and only affected 1 to 2 % of the burned areas. Sand-sized aggregates formed by fusing of finer soil materials in the severely burned soils. In some places, temperatures were high enough to produce a glassy slag.
Where the soil was severely burned, three distinct horizons formed: 1. light-colored wood-ash containing CaCO3, 2. a thin layer of soil reddened as a result of thermal alteration of goethite to hematite, and 3. a soil layered blackened by charring of soil organic matter.
X-ray diffraction and other mineralogical analyses showed that severe burning destroys kaolin minerals and severely alters other clay minerals, including chlorite, vermiculite, and biotite. Wildfires may contribute significantly to surface soil weathering over the course of thousands of years.