SAN FRANCISCO (AP) — Devastating California wildfires this year — and expectations of more to come under the extremes of climate change — prompted regulators Thursday to toughen rules for utility companies to keep power lines clear of brush and tree branches that can easily spark into flames. Public Utilities Commission president Michael Picker called the regulations adopted unanimously by the board "a major rewrite" of the state's fire-prevention rules for utilities as climate change drives up wildfire risks in much of California.