ESCI 1012 Lecture Notes - Lecture 24: Pore Space In Soil, Soot, Flame Retardant
Document Summary
Normally, vegetation of unburned areas has dramatic influence on soil moisture, runoff, and erosion. Roots help to hold soil in place. Organic debris (needles, leaves, twigs) soak up water, holding it until it can soak into ground rather than runoff downslope. Living vegetation also takes moisture out of soil. But wildfires can eliminate all of these. In addition, burning organic material can produce a water-resistant hydrocarbon residue that sinks in to fill soil pore spaces. This prevents water from soaking into the ground (hydrophobic soil) which greatly increases runoff. Hence soil erosion and as eroded soils fill stream channels flash floods increase as well as landslides since slopes can no longer hold back dirt or snow. These risks can be reduced by quickly planting or seeding burned slopes in order to reestablish vegetation as well as using organic barriers to slow runoff. Air pollution (smoke, soot and ash) in stratosphere can spread to cover much of the globe.
