A furnace of intense heat didn’t just incinerate the trees on 161,000 acres of the mountains above La Cañada Flintridge and Sunland-Tujunga in the fall of 2009.

It awakened the aliens.

Arundo. Spanish broom. Tree of heaven. These foreign plant species, that once laid dormant in the soil, came alive as a result of the 2009 Station Fire. Today, they are still wreaking havoc on streams and trails.

Like a cancer, arundo or giant reeds from southern Asia are taking over Big Tujunga Creek inch by inch. These non-native plants suck up five times the amount of water as California native reeds, silently robbing Angelenos of a major source of water because the creek supplies the water table and empties into the Los Angeles River, explains Edward Belden, Southern California program associate with the National Forests Foundation.

“We are going to go in and remove it,” Belden said. “Each acre of arundo removed is worth 20 acre-feet of water per year. If we take out 100 acres of arundo, we could save 2,000 acre-feet of water, enough water for 4,000 households per year.”

Equally ambitious is Robert Skillman’s crews of 18-24 year-old high school dropouts with the Los Angeles Conservation Corps. Skillman, environmental director, had a team perched nearly 5,000 feet up near the base of Strawberry Peak, tossing Spanish broom plants into a chipper.

Skillman pointed to an established row of these European invaders along a no-name trail damaged in the fire. “It is better to catch these early,” he said. His crews remove the plants, digging out root balls buried 3-to-4-feet deep using special tools.

So far, 300 stream miles of Spanish broom have been cleared in the Big Tujunga area since 2009, Belden said.

Using Proposition 84 grant monies, Skillman moves crews from South L.A., Northeast L.A., East L.A. and the South Bay into remote mountain areas to give them a taste of nature. “We don’t have a problem working outside the monument,” he said.

The LACC has worked extensively with the Concerned Off-Road Bicyclists Association, rebuilding burned-out trails in Big Tujunga. Their teams have helped reopen trails by replacing the wood and sometimes the entire structures, called Sutter walls, that hold the trails in place.

“We are repairing them on this trail on the east side of Strawberry Peak,” Skillman said.

One plant that is indigenous to California, called poodle-dog bush, leaves red rashes tantamount to shingles on passers-by that make contact. The crews move the trails around these poisonous plants.

“It is a fire opportunist,” said Steve Messer, president of CORBA’s L.A. and Ventura County chapter, who once was bed-ridden for two weeks with welts from the plant.

“But it is not all that bad. It has stabilized the slopes,” Skillman said.

The drought has dried out the poodle-dog bush and may be driving them back into dormancy, one of the only good things about the four years of low rainfall.

Down at Sunnyvale and Vogel Flat campgrounds, the NFF has brought work teams from Coca-Cola, Alcoa and Edison to remove tree of heaven, a species native to China, as well as arundo from the creek.

Volunteer crews also gathered acorns from remaining oak trees, where they are sent to the Rancho Santa Ana Botanic Garden in Claremont. There, botanists planted the seeds and nurtured the saplings until they were replanted into the Sunland-Tujunga soil near where hundreds of oak trees were lost in the fire.

At Vogel Flat, Belden pointed to the young oaks reaching for the sun around stumps of trees that died in the Station Fire. He bent down to get a closer look at a sapling encircled by a small, mesh fence.

“They are doing pretty well so far,” he said.