U.S. Joint Fire Science Program


Date of this Version


Document Type



Fire Science Brief, Issue 120, October 2010


US government work.


In September 2002, the Williams Fire burned 38,184 acres of chaparral steeplands, including more than 90 percent of the San Dimas Experimental Forest. The 1960 Johnstone Fire had burned many of the same watersheds some forty years earlier, thus providing opportunities to compare post-fire watershed response coupled with management efforts that had converted some native chaparral areas to grassland. With scant studies on soil water repellency, plant recovery, and their effects on watershed hydrology, managers face diffi culties in planning for erosion/run-off problems. The researchers delivered quantifi ed data on changing soil properties, the character and structure of regenerating plants, and the factors that produced sediment movement and run-off in the post-fi re landscape.