According to researchers who published a recent paper in the International Journal of Wildland Fire (Volume 18[7] 2009), climate change will increase the number and burn severity of fires in Yosemite National Park. Using fire records, weather data, and satellite imagery they analyzed the fires in the park that occurred between 1984 and 2005.
http://www.examiner.com/x-11680-Wildfire-Examiner~y2009m11d2-Climate-change-researchers-Yosemite-NP-to-have-19-more-fires