SAN DIEGO -- San Diego Gas & Electric is taking measures to help prevent wildfires in the future by replacing older wooden power poles with new steel versions.

On Friday, a helicopter hoisted 90-foot steel poles and placed them into the ground in Alpine to replace older wooden ones.

SDG&E is replacing the older poles in rural areas throughout San Diego County as part of a fire prevention and safety plan.

The company has 700 poles already installed to date, with thousands more over the next few years.

"Not only is the material fire resistant, but it enables us to design our system to withstand stronger winds," said Jennifer Ramp, of SDG&E.

SDG&E has taken a rash of criticism over the past year for its wooden power poles -- some decades old -- and the role the poles may have played during some of the devastating wildfires in 2007.

The new steel poles are part of SDG&E's plan to help keep rural communities safe at a cost significantly lower than undergrounding power lines, which cost about $1 million a mile.

"After the 2007 fires, that's when we started to look at our systems and say, 'Look we've had two catastrophic fires over the last decade, what can we do to make the system more robust, more fire resistant as we're probably going to have more fires as the years go,'" said Ramp.

The poles are fire resistant, wind resistant and measure about 30 inches across. More than 5,000 in all will be used to replace older poles, so when the next wildfire starts many rural areas will be better protected.

In Alpine, 52 poles will be replaced as part of SDG&E's plan.

SDG&E's pole-replacement project will also reach Valley Center, Escondido, El Cajon and Bonita, and should take another 3 to 4 years to complete.