Fig. 1

Study areas were located in California’s Sierra Nevada in two wilderness areas with long-established natural fire programs: Yosemite National Park’s Illilouette Creek Basin and Kings Canyon National Park’s Sugarloaf Valley. Shading indicates the number of times that areas have burned since 1970. Inset maps show sampling plots as black dots in relationship to the topography and number of times burned at each study site. Public data were collected beginning in the early 1900s. Field data were collected from 2002 to 2013 to observe naturally occurring patterns of forest and understory structure and composition in relationship to fire regime