Mineralogical and micromorphological modifications in soil affected by slash pile burn

Abstract

Silvicultural practices, such as slash pile burning, are commonly used for fire and ecosystem management. This management technique can drastically alter chemical, physical and biological soil properties due to the high temperatures achieved during the prolonged severe burn. Little is known, however, about the impact of high-temperature slash pile burning on soil mineralogical and micromorphological properties. Soil changes were investigated in Manitou Experimental Forest in Rocky Mountains of Central Colorado to identify possible temperature-induced modifications in mineralogical and micromorphological properties that can impact thermal conductivity in soil affected by slash pile burning. Prescribed burning did not affect clay and silt fraction mineralogy. However, changes in post-burn mineralogical composition were evident in sand fractions, when compared to the pre-burn mineralogy. These differences were attributed to the formation of Mn oxide/hydroxide coatings by the process of mass transport through soil with convective air current during the fire. Resinous pine species used as fire fuel were thought to be the source of Mn input. Micromorphological analysis also confirmed the presence of Mn coatings on sand-sized grains, as well as the presence of Mn nodules and microfabric enrichment.

Citation

Nobles, M. M.; Massman, W. J.; Mbila, M.; Butters, G. 2010. Mineralogical and micromorphological modifications in soil affected by slash pile burn. In: Viegas, D. X., ed. VI International Conference on Forest Fire Research; 2010 November 15-18; Coimbra, Portugal. Submission 288. Coimbra, Portugal: ADAI/CEIF, University of Coimbra. CD-ROM.