USA. California. The ruins of some of the 300 homes destroyed by wildfire in San Bernardino National Forest, west of Los Angeles, on October 23 2003. In that year, forest fires across the state resulted in economic losses of US$3.5 billion. Pests which make the forests more vulnerable to fires could become more common as a result of climate change. There may also be an increase in the warm, dry Sant Ana winds, intensifying the fire threat. 2004.