The role of fire and soil heating on water repellency in wildland environments: a review

This paper describes the heat transfer mechanisms operating as heat moves d ownward in the soil along steep temperature gradients during both wildfires and prescribed fires. The transfer of heat downward in the upper part of t he soil is enhanced by the vaporization and movement of water and organic c ompounds. Available information on the changes in the chemistry of vaporize d organic compounds is summarized and discussed. An operational theory desc ribing the formation of a highly water repellent soil condition during Ale is presented. The relationship between the formation of this fire-related w atershed condition and subsequent surface runoff and erosion from wildland ecosystems is explored. Worldwide literature describing fire-induced water repellency is reviewed and summarized. (C) 2000 Elsevier Science B.V. All r ights reserved.