A burning question for wildfire safety
Will Gov. Brown OK $1B plan to clear forests by logging and ‘prescribed’ blazes?
PINECREST >> The answer to the problem of California’s catastrophic megafires can be found in the ashes of this forest, where clusters of fragrant sugar pines stand strong, elegant and healthy.
Bark is charred. Logs are charcoal. But a strategy of selective logging, followed by a mannerly “prescribed burn,” has created a forest as clean and safe as a cathedral.
“Fire will always be part of California. The question is, are we going to burn on our terms?” said ecologist Eric Knapp, on a hike through his research project in this natural laboratory at Stanislaus Tuolumne Experimental Forest, a 1,700-acre U.S. Forest Service area in the central Sierra Nevada.
The alternative, say scientists, is a continued sequence
of fires that start during the most extreme weather conditions, ignite dense fuel, then spread ferociously out of control.
As the Delta Fire races through a swath of Shasta Trinity National Forest and private timberland — forcing the weekend closure of a nearly 50-mile stretch of Interstate 5 north of Redding, California’s link to Oregon — policymakers will look to such research to guide the state’s proposed new commitment of $1 billion to reduce the risk of mega-wildfires across the state.
The legislation, if signed by Gov. Jerry Brown, commits $165 million a year for five years to thin forests and $35 million a year for five years to fund prescribed burning projects.
The majority of the forests now burning in the fast-moving Delta Fire haven’t seen fire since the early 1900s, when records were first kept, according to Knapp.
A similar fate could await other woodlands. We’re far behind in forest management, according to John Laird, California’s secretary for Natural Resources. About 500,000 acres of forest each year need to be treated in California; last year, we treated only half that.
A walk through almost any woods in California reveals the immensity of the problem. Many forests of the Sierra Nevada are two to three times denser than they were historically, when small and frequent fires were routine, say scientists.
Crowded trees struggled to compete for water, especially during the two severe and sustained droughts of 1987-1992 and 2012-2017. Stress weakened their natural defenses. Populations of predatory bark beetles surged. Forest floors are
carpeted with debris.
About 129 million trees now stand ready to ignite.
“It’s a mess of a forest,” said Knapp of the U.S. Forest Service, as he hiked through thick branches of sugar pine, dubbed “the king of the conifers” by naturalist John Muir, on an unthinned and unburned parcel of the experimental plots. The research forest was established in 1943 to study how different techniques affect a landscape.
Meanwhile, over the past century we’ve been snuffing out every spark.
This absolutist attitude to wildfires initially made sense. America was stunned by the Great Fire of 1910 in Idaho and Montana, which killed 87 people and burned three million acres, including entire towns. In its aftermath, the U.S. Forest Service promoted a “10 a.m.” policy, with the goal of suppressing all fires by 10 a.m. of the day following their report.
“Fuels have been accumulating for decades now, without any intervention,” said Jim Branham of the Sierra Nevada Conservancy.
About 98 percent of all wildfires are suppressed before they reach 300 acres in size. What happens to the other 2 percent of fires? They escape containment and explode into “megafires” in fuel-loaded forests, under often extreme weather conditions, such as heat and high winds.
The consequences of “megafires” are far more catastrophic than historic burns. Firefighters perish. Entire stands of trees are incinerated. Heat sterilizes the forest floor. And nearby communities are put at risk.
“The problem has come back to bite us in the butt,” said plant ecologist Malcolm North of UC Davis, who studies the role of fire in the Teakettle Experimental Forest, near Fresno.
This year’s sequence of “megafires” has been so severe
that Cal Fire says it’s running out of money and needs another $234 million to get through the season. The state will likely dip into budget reserves for the eighth time in 10 years to cover the cost of suppression.
Our fecund forests grow more flammable every day. The state’s Climate Change Assessment report, released last month, predicts that the acreage consumed by wildfires in an average year will soar 77 percent by the end of the century. That’s about a half-million acres of additional wildfires each year — the equivalent of two Carr Fires.
Knapp’s experimental plots use two different approaches to logging, conducted in 2011. In some, trees were removed uniformly. They stand like a regiment of soldiers, wellspaced and similar in age. In others, they were removed in groups, leaving clusters of trees ranging in age and size to remain.
But logging alone isn’t enough, because it’s not thorough enough, say scientists. “We can’t thin our way out of this problem,” North said.
Following logging, prescribed burns were set to Knapp’s plots in 2013. Because forests are logged, with trees removed, the fire is less intense and easier to control, he said.
Burning is a carefully choreographed dance, involving teams of 50 or 60 people, as well as fire engines and hoses. The day starts at dawn, with a meteorologist watching weather, wind and humidity. Each site has a secured perimeter, cleared of debris.
Wielding a “drip torch,” which drops a gas-diesel mix, crews ignite spots or stripes of the forest. Because flames want to run uphill, they do the reverse, called “back burning,” starting high and then dropping down a ridge. The fire
ends at each strip of black char. Any rogue flames are quickly doused with water.
It’s slow and tedious work. The size of each burn is limited by how much can be done in one day; the average fire averages only 90 to 100 acres in size. Afterwards, crews stay to monitor.
In the months and years that follow logging and fires, Knapp’s team tracks the forest changes, studying plant growth and wildlife.
The “clustered” approach to thinning sugar pines seems the best, slowing future fires. “It breaks up the stand, creating fuel discontinuity into the future,” he said.
Striding through a meadow of ceanothus and manzanita shrubs, he pointed out the diversity in the new vegetation, creating food for wildlife and room for species like oak, white fir and cedar.
A 185-foot tall sugar pine, its canopy green and glorious, reached for the sky. Below it, tiny pine seedlings poked through the duff. Bumblebees hovered around thistle blossoms. A garter snake slithered into a hole.
To be sure, prescribed burns are controversial. In 2000, a burn escaped control and destroyed 200 buildings, leaving people homeless. And they create smoke, causing breathing problems.
Logging is also controversial. The Sierra Club California urges the state to instead tighten building codes, better enforce rules requiring defensible space and limit development in high-risk areas.
“But we really only have two options,” said North.
“We can continue with what we’re doing, kicking the can down the road,” he said. “Or we can be pro-active, putting the instrument of fire back on the landscape.”