A team of 45 scientists, economists and engineers have been commissioned by the US Forest Service to document Station Fire losses, predict the future impact of those losses and make recommendations to minimize risks in the future.
The Station Fire charred plant life and seared soil as it burned across 160,000 acres of the Angeles National Forest.
Before the fire, healthy shrubs and soil diffused and absorbed rainfall as it made its way down mountainsides to rivers and reservoirs, according to US Forest Service soil scientist Eric Nicita.
“If it rains on unburned areas, little plants act like pumps” and soil absorbs water into roots and the water table Nicita said.
But the Station Fire has made healthy shrubs and soil a scarce commodity in the Angeles National Forest, according to Nicita.
In burned areas, “hydrophobic compounds turn into gases and puts a wax like coating on the soil,” Nicita said. “The longer water has to accumulate, the greater the chance it has to cause erosion.”
Forest fires are a natural process in the chaparral shurb land that makes up the Angeles National Forest, according to Jon Keeley a research ecologist at the US Geological Survey and professor at the University of California Los Angeles.
“The best evidence we have to date indicates those ecosystems have had fires like this for probably 10 to 20 million years,” Keeley said. “Most of what burned is mature shrub land and the diversity of plant species will probably be ten times higher than it was before the fire.”
While scientists agree that plant life and soil will eventually recover, in the meantime mountainsides could become conveyors of mud slides, sediment can block rivers and the delicate process of watershed that starts in the Angeles National Forest and ends below ground in the water table, or the Pacific Ocean, could be devastated, according to officials.
“There will be flooding and there could be debris slides,” Los Angeles County Public Department of Works spokesman Gary Bouze said. “We do have flood channel systems to handle that, but we are concerned by the size of this fire.”
Kyle Wright is one of four hydrologists assigned to compare watershed capacity before and after the fire.
“Water won’t be able to infiltrate as well as it did pre-fire, the biggest thing is it increases your peak flows,” Wright said. “We are currently using several different (computer) programs to model what we might expect from different storm events.”
Keith Stockman is one of several economists who performs “cost/value analysis” to help determine what, if any, preventive measure will be recommend by the team.
“I try to help the team stay focused on which dangers are going to cause market concern,” Stockman said. “If those values are a high-risk situation, we will discuss some treatment options.”
Possible treatments range from constructing log barriers to laying down mulch.
“Mulch reduces water energy and provides cover for vegetation,” Stockman said.
However, the steep mountainsides and canyons of the Angeles National may render many of those treatments inadequate.
“There’s a lot of treatments, but what we want to do is make sure those treatments are effective,” Stockman said. “It’s really a case-by-case basis.”
Flooding could also devastate endangered populations of frogs and fish in the national forest, according to wildlife biologist Mark Stamer.
“If we lose whole populations on this mountain range that’s a huge deal,” he said.
The mountain yellow-legged frog, Santa Ana sucker, Speckled Dace and Arroyo Chub are among the species that could be carried into the ocean and flood channels to die.
“Because of urbanization, they’re going to get washed into debris basins,” Stamer said. “When those basins are flushed out, those species will be flushed out and they wont be able to repopulate upstream.”
A number of large mammals such as deer and bears, have already sustained losses to their population.
“This fire moved so fast, and was so large, animals couldn’t escape,” Stamer said.
The ability of those animal species to survive as the forest recovers is also in question.
“Under normal conditions they could survive,” Stamer said. “But because you have this island of habitat that’s been significantly reduced by development, they have nowhere to go.”
Foreign and invasive species of plants also bear a threat to the barren mountain slopes and eco-system of the forest, according to the executive director of the Los Angeles and San Gabriel Rivers Watershed Council Nancy Steele.
Steele is concerned individuals will try to reseed or plant trees in the burned areas.
While well intentioned, these acts can cause more harm than good, according to Steele.
“The seed mixes are generic for all California… so you can get all sorts of non-native things growing,” she said. “Plus no matter how good the mix, there is always some percent of weed seeds.”
But perhaps those most at risk from damage sustained in the Station Fire are homeowners who live directly below burned mountainsides.
The Department of Public Works is urging those homeowners to contact them for on advice on how to best protect their homes, said Mark Pestrella – deputy director of the county Department of Public Works.
The US Forest Service team is scheduled to conclude their report and make recommendations to local and federal authorities Thursday, according to US Forest Service public information officer Richard Hadley.