1. Effects of Wildfires on Landscape Evolution in Southern California Julia Rogers GE154 6 May 2015

2. Why study wildfires? From Westerling et al. 2006

3. Bedrock of Southern California From Jennings et al. 1977

4. Vegetation Communities Chaparral Systems Rely on fires as part of their natural cycles 90% of annual rainfall between November and April Dry Ravel Debris flows are common after fires Sonoran Desert Large portion of the landscape Frequently burned Low-intensity fires Little effect on landscape evolution From http://www.resecol.wur.nl/gest/privateGEST/North%20America/Dry%20 site/Landscape%20&%20vegetation/2005_02032008_South_America_3 0382.JPG From http://www.azfirescape.org/sites/azfirescape.org/files/dsc007 38.jpg

5. Mass Wasting Debris flows range from small to large Wildfires increase likelihood of a slope to fail 2009 Station Fire From Cannon et al., 2009

6. Fluvial Transport Indirect effect from mass wasting Erosion of larger materials Change in depth and course From http://geologycafe.com/images/arroyo_seco2.jpg

7. Soils and Water Repellency Water repellency is created by: 1.Heat of the fire 2.Quantity of organic matter in the ecosystem Causes less water to be absorbed and more runoff From DeBano 1981

8. Chemistry of the Substrates Increase in pH due to the ash High levels of certain metals including lead, zinc, chromium, and copper From http://www.iarc.uaf.edu/sites/default/files/fig1.jpg

9. Citations DeBano, L. F.: 1981. Water repellent soils: a state-of-the-art (Vol. 46). US Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. Cannon, S. H., Boldt, E. M., Laber, J. L., Kean, J. W., and D.M. Staley: 2011. Rainfall intensity–duration thresholds for postfire debris-flow emergency-response planning. Natural Hazards, 59(1), p. 209-236. Jennings, C.W., Strand, R.G., and Rogers, T.H: 1977. Geologic map of California. California Division of Mines and Geology. Westerling, A. L., Hidalgo, H. G., Cayan, D. R., and T.W. Swetnam: 2006. Warming and earlier spring increase western US forest wildfire activity. Science, 313(5789), p. 940-943.

10. Questions?