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International Journal of Wildland Fire International Journal of Wildland Fire Society
Journal of the International Association of Wildland Fire
RESEARCH ARTICLE

Predicting post-fire hillslope erosion in forest lands of the western United States

Mary Ellen Miller A C , Lee H. MacDonald A , Peter R. Robichaud B and William J. Elliot B
+ Author Affiliations
- Author Affiliations

A Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, CO 80523-1476, USA.

B US Department of Agriculture, Forest Service, Rocky Mountain Research Station, Moscow, ID 83843, USA.

C Corresponding author. Present address: Michigan Technological University, Michigan Tech Research Institute, 3600 Green Court, Suite 100, Ann Arbor, MI 48105, USA. Email: mmaryellen@gmail.com

International Journal of Wildland Fire 20(8) 982-999 https://doi.org/10.1071/WF09142
Submitted: 12 December 2009  Accepted: 23 February 2011   Published: 25 October 2011

Abstract

Many forests and their associated water resources are at increasing risk from large and severe wildfires due to high fuel accumulations and climate change. Extensive fuel treatments are being proposed, but it is not clear where such treatments should be focussed. The goals of this project were to: (1) predict potential post-fire erosion rates for forests and shrublands in the western United States to help prioritise fuel treatments; and (2) assess model sensitivity and accuracy. Post-fire ground cover was predicted using historical fire weather data and the First Order Fire Effects Model. Parameter files from the Disturbed Water Erosion Prediction Project (WEPP) were combined with GeoWEPP to predict post-fire erosion at the hillslope scale. Predicted median annual erosion rates were 0.1–2 Mg ha–1 year–1 for most of the intermountain west, ~10–40 Mg ha–1 year–1 for wetter areas along the Pacific Coast and up to 100 Mg ha–1 year–1 for north-western California. Sensitivity analyses showed the predicted erosion rates were predominantly controlled by the amount of precipitation rather than surface cover. The limited validation dataset showed a reasonable correlation between predicted and measured erosion rates (R2 = 0.61), although predictions were much less than measured values. Our results demonstrate the feasibility of predicting post-fire erosion rates on a large scale. The validation and sensitivity analysis indicated that the predictions are most useful for prioritising fuel reduction treatments on a local rather than interregional scale, and they also helped identify model improvements and research needs.

Additional keywords: ground cover, modelling, sensitivity analysis, WEPP.


References

Agee JK (1993) ‘Fire Ecology of Pacific Northwest Forests.’ (Island Press: Washington, DC)

Benavides-Solorio J, MacDonald LH (2005) Measurement and prediction of post-fire erosion at the hillslope scale, Colorado Front Range. International Journal of Wildland Fire 14, 457–474.
Measurement and prediction of post-fire erosion at the hillslope scale, Colorado Front Range.Crossref | GoogleScholarGoogle Scholar |

Beven KJ (2001) ‘Rainfall-runoff Modelling: the Primer.’ (Wiley: Chichester, UK)

Booker FA, Dietrich WE, Collins LM (1993) Runoff and erosion after the Oakland Firestorm – expectations and observations. California Geology 46, 159–173.

Booker FA, Dietrich WE, Collins LM (1995) The Oakland Hills Fire of 20 October 20 [sic, 1991]: an evaluation of post-fire response. In ‘Brushfires in CaliforniaWildlands: Ecology and Resource Management’. (Eds JE Keeley, T Scott) pp. 163–170. (International Association of Wildland Fire: Fairfield, WA)

Bormann B, Homann P, Cromack K Jr., Darbyshire R, Grant G, Molina, R (2005) Ecosystem effects and propagation of the Biscuit Fire across the large-scale plots of the long-term ecosystem productivity experiment. Report to the Joint Fire Science Program from project AFP3-2003. (Boise, ID)

Brough D, Lawrence P, Fraser G, Rayner D, Le Grand J (2004) Improved inputs for prediction of regional-scale soil erosion potential for Queensland. In ‘Proceedings ISCO 2004’, 4–8 July 2004, Brisbane, QLD. (International Soil Conservation Organisation: Brisbane, QLD)

Brown JK, Marsden MA, Ryan KC, Reinhardt ED (1985) Predicting duff and woody fuel consumed by prescribed fire in Northern Rocky Mountains. USDA Forest Service, Intermountain Forest and Range Experiment Station Research Paper INT-337. (Ogden, UT)

Bunte K, MacDonald LH (1999) Scale considerations and the detection of sedimentary cumulative watershed effects. National Council of Air and Stream Improvement, Technical Bulletin 776. (Research Triangle Park, NC)

Bunte K, Poesen J (1994) Effects of rock fragment size and cover on overland flow hydraulics, local turbulence and sediment yield on an erodible soil surface. Earth Surface Processes and Landforms 19, 115–135.
Effects of rock fragment size and cover on overland flow hydraulics, local turbulence and sediment yield on an erodible soil surface.Crossref | GoogleScholarGoogle Scholar |

Burgan RE, Klaver RW, Klaver JM (1998) Fuel models and fire potential for satellite and surface observations. International Journal of Wildland Fire 8, 159–170.
Fuel models and fire potential for satellite and surface observations.Crossref | GoogleScholarGoogle Scholar |

Cannon SH (2001) Debris-flow generation from recently burned watersheds. Environmental & Engineering Geoscience 7, 321–341.

Cochrane TJ, Flanagan DC (2005) Effect of DEM resolutions in the runoff and soil loss predictions of the WEPP watershed model. Transactions of the ASAE 48, 109–120.

Conroy WJ (2005) A coupled upland-erosion and hydrodynamic-sediment transport model for evaluating management-related sediment erosion in forested watersheds. PhD dissertation, Washington State University, Pullman, WA.

Daly C, Taylor GH, Gibson WP (1997) The PRISM approach to mapping precipitation and temperature. In ‘Proceedings 10th Conference on Applied Climatology’, 20–24 October 1997, Reno, NV. pp. 10–12. (American Meteorological Society: Boston, MA)

Dissmeyer GE, Foster GR (1981) Estimating the cover-management factor (C) in the Universal Soil Loss Equation for forest conditions. Journal of Soil and Water Conservation 36, 235–240.

Edwards TK, Glysson GD (1999) Field methods for measurement of fluvial sediment. US Geological Survey, Open-File Report 86–531. (Washington, DC)

Elliot WJ (2004) WEPP internet interfaces for forest erosion prediction. Journal of the American Water Resources Association 40, 299–309.
WEPP internet interfaces for forest erosion prediction.Crossref | GoogleScholarGoogle Scholar |

Elliot WJ, Hall DE, Scheele DL (1999) Rock:Clime Rocky Mountain Research Station Stochastic Weather Generator Technical Documentation. USDA Forest Service, Rocky Mountain Research Station. (Moscow, ID) Available at http://forest.moscowfsl.wsu.edu/fswepp/docs/rockclimdoc.html [Verified 5 October 2009]

Elliot WJ, Hall DE, Scheele DL (2000) Disturbed WEPP (Draft 02/2000) WEPP interface for disturbed forest and range runoff, erosion and sediment delivery. USDA Forest Service, Rocky Mountain Research Station (Moscow, ID) Available at http://forest.moscowfsl.wsu.edu/fswepp/docs/distweppdoc.html [Verified 23 October 2009]

Elliott JG, Parker RS (2001) Developing a post-fire flood chronology and recurrence probability from alluvial stratigraphy in the Buffalo Creek watershed, Colorado, USA. Hydrological Processes 15, 3039–3051.
Developing a post-fire flood chronology and recurrence probability from alluvial stratigraphy in the Buffalo Creek watershed, Colorado, USA.Crossref | GoogleScholarGoogle Scholar |

Flanagan DC, Nearing MA (1995) USDA – Water Erosion Prediction Project: hillslope profile and watershed model documentation. USDA-ARS National Soil Erosion Research Laboratory, NSERL Report 10. (West Lafayette, IN)

Flannigan MD, Stocks BJ, Wotton BM (2000) Climate change and forest fires. The Science of the Total Environment 262, 221–229.
Climate change and forest fires.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXotleru78%3D&md5=91498dd2c712b31b6b0c218e2d0fd9a0CAS |

Forrest CL, Harding MV (1994) Erosion and sediment control: preventing additional disasters after the southern California fires. Journal of Soil and Water Conservation 49, 535–541.

Fosberg MA, Rothermal RC, Andrews PL (1981) Moisture content calculations for the 100-hour timelag fuels. Forest Science 27, 19–26.

Fox D, Berolo W, Carrega P, Darboux F (2006) Mapping erosion risk and selecting sites for simple erosion control measures after a forest fire in Mediterranean France. Earth Surface Processes and Landforms 31, 606–621.
Mapping erosion risk and selecting sites for simple erosion control measures after a forest fire in Mediterranean France.Crossref | GoogleScholarGoogle Scholar |

Gabet EJ (2003) Sediment transport by dry ravel. Journal of Geophysical Research 108, 2049
Sediment transport by dry ravel.Crossref | GoogleScholarGoogle Scholar |

GAO (1999) Western national forests: a cohesive strategy is needed to address catastrophic wildland fire threats. US General Accounting Office, Report GAO/RCED-99-65. (Washington, DC)

GAO (2007) Wildland fire management: better information and a systematic process could improve agencies’ approach to allocating fuel reduction funds and selecting projects. US General Accounting Office, Report GAO-07-1168. (Washington, DC)

Garbrecht J, Martz LW (1999) TOPAZ: an automated digital landscape analysis tool for topographic evaluation, drainage identification, watershed segmentation and subcatchment parameterization. USDA Agricultural Research Service, Publication GRL 99–1. (El Reno, OK)

Guyette RP, Dey D (2004) The effects of humans and topography on wildland fire, forests, and species abundance. USDA Forest Service, Southern Research Station General Technical Report SRS-73. (Asheville, NC)

Haan CT, Barfield BJ, Hayes JC (1994) ‘Design Hydrology and Sedimentology for Small Catchments.’ (Academic Press: San Diego, CA)

Hall BL, Brown TJ, Bradshaw LS, Jolly WM, Nemani R (2003) National standardized energy release component forecasts. In ‘Proceedings Second International Wildland Fire Ecology and Fire Management Congress and Fifth Symposium of Fire and Forest Meteorology’, 16–20 November 2003, Orlando, FL. J11.10. (American Meteorological Society: Boston, MA) Available at http://ams.confex.com/ams/pdfpapers/66258.pdf [Verified 17 August 2011]

Istanbulluoglu E, Tarboton DG, Pack RT, Luce C (2002) A probabilistic approach for channel initiation. Water Resources Research 38, 1325–1338.
A probabilistic approach for channel initiation.Crossref | GoogleScholarGoogle Scholar |

Keane RE, Ryan KC, Veblen TT, Allen CD, Logan J, Hawkes B (2002) Cascading effects of fire exclusion in Rocky Mountain ecosystems: a literature review. USDA Forest Service, Rocky Mountain Research Station, General Technical Report RMRS-GTR-91. (Fort Collins, CO)

Krammes JL (1960) Erosion from mountain side slopes after fire in southern California. USDA Forest Service, Pacific Southwest Forest and Range Experiment Station, Research Note 171. (Berkeley, CA)

Laflen JM, Elliot WJ, Flanagan DC, Meyer CR, Nearing MA (1997) WEPP – predicting water erosion using a process-based model. Journal of Soil and Water Conservation 52, 96–102.

Larsen IJ, MacDonald LH (2007) Predicting post-fire sediment yields at the hillslope scale: testing RUSLE and Disturbed WEPP. Water Resources Research 43, W11412
Predicting post-fire sediment yields at the hillslope scale: testing RUSLE and Disturbed WEPP.Crossref | GoogleScholarGoogle Scholar |

Larsen IJ, MacDonald LH, Brown E, Rough D, Welsh MJ, Pietraszek JH, Libohova Z, Benavides-Solorio JD, Schaffrath K (2009) Causes of post-fire runoff and erosion: water repellency, cover, or soil sealing? Soil Science Society of America Journal 73, 1393–1407.
Causes of post-fire runoff and erosion: water repellency, cover, or soil sealing?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXos1Ggtr8%3D&md5=b6140bd1749180b8340273c9980e6169CAS |

Lentile L, Morgan P, Hardy C, Hudak A, Means R, Ottmar R, Robichaud P, Kennedy Sutherland E, Szymoniak J, Way F, Fites-Kaufman J, Lewis S, Mathews E, Shovik H, Ryan K (2007) Value and challenges of conducting rapid-response research on wildland fires. USDA Forest Service, Rocky Mountain Research Station, General Technical Report RMRS-GTR-193. (Fort Collins, CO)

Libohova Z (2004) Effects of thinning and a wildfire on sediment production rates, channel morphology, and water quality in the upper South Platte River watershed. MSc thesis, Colorado State University, Fort Collins, CO.

MacDonald LH, Sampson RW, Brady D, Juarros L, Martin D (2000) Predicting post-fire erosion and sedimentation risk on a landscape scale: a case study from Western Colorado. Journal of Sustainable Forestry 11, 57–87.
Predicting post-fire erosion and sedimentation risk on a landscape scale: a case study from Western Colorado.Crossref | GoogleScholarGoogle Scholar |

Miller JD, Nyhan JW, Yool SR (2003) Modeling potential erosion due to the Cerro Grande Fire with a GIS-based implementation of the Revised Universal Soil Loss Equation. International Journal of Wildland Fire 12, 85–100.
Modeling potential erosion due to the Cerro Grande Fire with a GIS-based implementation of the Revised Universal Soil Loss Equation.Crossref | GoogleScholarGoogle Scholar |

Minkowski M, Renschler CS (2008) GeoWEPP for ArcGIS 9.x full version manual. (Department of Geography, The State University of New York at Buffalo, NY) Available at http://www.geog.buffalo.edu/~rensch/geowepp/arc_index.html [Verified 25 October 2009]

Montgomery DR, Dietrich WE (1989) Source areas, drainage density and channel initiation. Water Resources Research 25, 1907–1918.
Source areas, drainage density and channel initiation.Crossref | GoogleScholarGoogle Scholar |

Moody JA, Kinner DA (2006) Spatial structures of stream and hillslope drainage networks following gully erosion after wildfire. Earth Surface Processes and Landforms 31, 319–337. [Published online ahead of print 27 September 2005] https://doi.org/10.1002/ESP.1246

Moody JA, Martin DA (2001) Hydrologic and sedimentation response of two burned watersheds in Colorado. US Geological Survey, Water Resources Investigative Report 01–4122. (Denver, CO)

Moody JA, Martin DA (2009) Synthesis of sediment yields after wildland fire in different rainfall regimes in the western United States. International Journal of Wildland Fire 18, 96–115.
Synthesis of sediment yields after wildland fire in different rainfall regimes in the western United States.Crossref | GoogleScholarGoogle Scholar |

National Fire and Aviation Management (2005) Fire and weather data. Available at http://fam.nwcg.gov/fam-web/weatherfirecd/ [Verified 25 October 2009]

Neary DG, Ryan KC, DeBano LF (2005) Wildland fire in ecosystems: effects of fire on soils and water. USDA Forest Service, Rocky Mountain Research Station, General Technical Report 42, vol. 4. (Ogden, UT)

Nicks AD, Lane LJ, Gander GA (1995) Weather generator. In ‘USDA – Water Erosion Prediction Project Hillslope Profile and Watershed Model Documentation’. (Eds DC Flanagan and MA Nearing) pp. 2.1–2.22. (USDA Agricultural Research Service: West Lafayette, IN)

Oreskes N, Shrader-Frechette K, Belitz K (1994) Verification, validation and confirmation of numerical models in the earth-sciences. Science 263, 641–646.
Verification, validation and confirmation of numerical models in the earth-sciences.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3cvit1OrsQ%3D%3D&md5=bb4fb95316a4acaac49cf9879c8749d9CAS |

Ottmar RD, Sandberg DV (1985) Calculating moisture content for 1000-hour timelag fuels in western Washington and western Oregon. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Research Paper PNW-336. (Portland, OR)

Pietraszek J (2006) Controls on post-fire erosion at the hillslope scale, Colorado Front Range. MSc thesis, Colorado State University, Fort Collins, CO.

Reinhardt ED (2003) Using FOFEM 5.0 to estimate tree mortality, fuel consumption, smoke production and soil heating from wildland fire. In ‘Proceedings Second International Wildland Fire Ecology and Fire Management Congress and Fifth Symposium of Fire and Forest Meteorology’, 16–20 November 2003, Orlando, FL. 5.2. (American Meteorological Society: Boston, MA) Available at http://ams.confex.com/ams/pdfpapers/65232.pdf [Verified 17 August 2011]

Reinhardt ED, Keane RE, Brown JK (1997) First Order Fire Effects Model: FOFEM 4.0, user’s guide. USDA Forest Service, Intermountain Research Station, General Technical Report INT-GTR-344. (Ogden, UT)

Renard KG, Foster GR, Weesies GA, McCool DK, Yoder DC (1997) Predicting soil erosion by water: a guide to conservation planning with the Revised Universal Soil Loss Equation (RUSLE). USDA Agriculture Handbook 703. (Washington, DC)

Renschler CS (2003) Designing geo-spatial interfaces to scale process models: the GeoWEPP approach. Hydrological Processes 17, 1005–1017.
Designing geo-spatial interfaces to scale process models: the GeoWEPP approach.Crossref | GoogleScholarGoogle Scholar |

Robichaud PR (2000) Fire effects on infiltration rates after prescribed fire in northern Rocky Mountain forests, USA. Journal of Hydrology 231–232, 220–229.
Fire effects on infiltration rates after prescribed fire in northern Rocky Mountain forests, USA.Crossref | GoogleScholarGoogle Scholar |

Robichaud PR, Brown RE (1999) What happened after the smoke cleared: onsite erosion rates after a wildfire in eastern Oregon. In ‘Proceedings Annual Summer Specialty Conference (Track 2: Wildland hydrology)’, 30 June–2 July 1999, Bozeman, MT. (Eds DS Olsen, JP Potyondy) pp. 419–426. (American Water Resources Association: Middleburg, VA) [Revised 2000]

Robichaud PR, Brown RE (2002) Silt fences: an economical technique for measuring hillslope soil erosion. USDA Forest Service, Rocky Mountain Research Station, General Technical Report RMRS-GTR-94. (Fort Collins, CO)

Robichaud PR, Elliot WJ, Pierson FB, Hall DE, Moffet CA (2007) Predicting post-fire erosion and mitigation effectiveness with a web-based probabilistic model. Catena 71, 229–241.
Predicting post-fire erosion and mitigation effectiveness with a web-based probabilistic model.Crossref | GoogleScholarGoogle Scholar |

Robichaud PR, Lewis SA, Laes DYM, Hudak AT, Kokaly RF, Zamudio JA (2007) Post-fire soil burn severity mapping with hyperspectral image unmixing. Remote Sensing of Environment 108, 467–480.
Post-fire soil burn severity mapping with hyperspectral image unmixing.Crossref | GoogleScholarGoogle Scholar |

Robichaud PR, Wagenbrenner JW, Brown RE, Wohlgemuth PM, Beyers JL (2008) Evaluating the effectiveness of contour-felled log erosion barriers as a post-fire runoff and erosion mitigation treatment in the western United States. International Journal of Wildland Fire 17, 255–273.
Evaluating the effectiveness of contour-felled log erosion barriers as a post-fire runoff and erosion mitigation treatment in the western United States.Crossref | GoogleScholarGoogle Scholar |

Rollins MG (2009) LANDFIRE: a nationally consistent vegetation, wildland fire, and fuel assessment. International Journal of Wildland Fire 18, 235–249.
LANDFIRE: a nationally consistent vegetation, wildland fire, and fuel assessment.Crossref | GoogleScholarGoogle Scholar |

Sampson AW (1944) Effect of chaparral burning on soil erosion and on soil-moisture relations. Ecology 25, 171–191.
Effect of chaparral burning on soil erosion and on soil-moisture relations.Crossref | GoogleScholarGoogle Scholar |

Sampson RN, Atkinson RD, Lewis JW (2000) Indexing resource data for forest health decision making. Journal of Sustainable Forestry 11, 1–14.
Indexing resource data for forest health decision making.Crossref | GoogleScholarGoogle Scholar |

Scheele DL, Elliot WJ, Hall DE (2001) Enhancements to the CLIGEN weather generator for mountainous or custom applications. In ‘Soil Erosion Research for the 21st Century’. (Eds JC Ascough II and DC Flanagan) pp. 392–395. (American Society of Agricultural Engineers: Saint Joseph, MI)

Schmidt KM, Menakis JP, Hardy CC, Hann WJ, Bunnell DL (2002) Development of coarse-scale spatial data for wildland fire and fuel management. USDA Forest Service, Rocky Mountain Research Station, General Technical Report RMRS-GTR-87. (Fort Collins, CA)

Shakesby RA, Boakes DJ, Coelho C de OA, Goncalves AJB, Walsh RPD (1996) Limiting the soil degradational impacts of wildfire in pine and eucalyptus forests in Portugal: a comparison of alternative post-fire management practices. Applied Geography 16, 337–355.
Limiting the soil degradational impacts of wildfire in pine and eucalyptus forests in Portugal: a comparison of alternative post-fire management practices.Crossref | GoogleScholarGoogle Scholar |

Singer MJ, Munns DN (2002) ‘Soils: an Introduction.’ (Prentice Hall Publishers: Upper Saddle River, NJ)

Soto B, Diaz-Fierros F (1998) Runoff and soil erosion from areas of burnt scrub: comparison of experimental results with those predicted by the WEPP model. Catena 31, 257–270.
Runoff and soil erosion from areas of burnt scrub: comparison of experimental results with those predicted by the WEPP model.Crossref | GoogleScholarGoogle Scholar |

Spigel KM, Robichaud PR (2007) First-year post-fire erosion rates in Bitterroot National Forest, Montana. Hydrological Processes 21, 998–1005.
First-year post-fire erosion rates in Bitterroot National Forest, Montana.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXlsVSqtLk%3D&md5=710dac4caddf9e7bfcc481b62b5bbe94CAS |

Sugihara NG, van Wagtendonk JW, Shaffer KE, Fites-Kaufman J, Thode AE (Eds) (2006) ‘Fire in California’s Ecosystems.’ (University of California Press: Berkeley, CA)

The National Map LANDFIRE (2005) LANDFIRE Rapid Assessment Fire Regimes layer. US Geological Survey. Available at http://gisdata.usgs.net/website/landfire/ [Verified 25 October 2009]

The Nature Conservancy, USDA Forest Service, US Department of the Interior (2005) ‘LANDFIRE Rapid Assessment Modeling Manual, Version 2.1.’ (Boulder, CO)

Tiedemann AR, Conrad CE, Dieterich JH, Hornbeck JW, Megahan WF (1979) Effects of fire on water. A state-of-knowledge review. USDA Forest Service, General Technical Report WO-10. (Washington, DC)

USDA (1991) State soil geographic (STATSGO) data base data use information. USDA Miscellaneous Publication 1492. (Washington, DC)

USDA Forest Service (2002) FireFamily Plus version 3.0, software and user’s guide. USDA Forest Service, Rocky Mountain Research Station. Available at http://www.fs.fed.us/fire/planning/nist/distribu.htm [Verified May 2005]

USGS (2002) The national map – elevation. USGS Fact Sheet 106–02. Available at http://nationalmap.gov/ [Verified 25 October 2009]

Walling DE (1983) The sediment delivery problem. Journal of Hydrology 65, 209–237.
The sediment delivery problem.Crossref | GoogleScholarGoogle Scholar |

Walsh RPD, Voight PJ (1977) Vegetation litter; an underestimated variable in hdyrology and geomorphology. Journal of Biogeography 4, 253–274.
Vegetation litter; an underestimated variable in hdyrology and geomorphology.Crossref | GoogleScholarGoogle Scholar |

Westerling AL, Hidalgo HG, Cayan DR, Swetnam TW (2006) Warming and earlier spring increase western US forest wildfire activity. Science 313, 940–943.
Warming and earlier spring increase western US forest wildfire activity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XotFCitbo%3D&md5=0c50ad3f867d0006079217644781016cCAS |

Wischmeier WH (1976) Use and misuse of the Universal Soil Loss Equation. Journal of Soil and Water Conservation 31, 5–9.

Wohlgemuth PM (2003) Hillslope erosion following the Williams Fire on the San Dimas Experimental Forest, Southern California. In ‘Proceedings Second International Wildland Fire Ecology and Fire Management Congress and Fifth Symposium of Fire and Forest Meteorology’, 16–20 November 2003, Orlando, FL. 1B.8. (American Meteorological Society: Boston, MA) Available at http://ams.confex.com/ams/pdfpapers/67248.pdf [Verified 17 August 2011]

Yao C (2009) Rill erosion initiation and effect of DEM resolution. PhD dissertation, Washington State University, Pullman, WA.

Yu B (2002) Using CLIGEN to generate RUSLE climate inputs. Transactions of the ASAE 45, 993–1001.

Zhang JX, Wu JQ, Chang K, Elliot WJ, Dun S (2009) Effects of DEM source and resolution on WEPP hydrologic and erosion simulation: a case study of two forest watersheds in northern Idaho. Transactions of the ASAE 52, 447–457.

Zhu Z, Evans DL (1994) US forest types and predicted percent forest cover from AVHRR data. Photogrammetric Engineering and Remote Sensing 60, 525–531.