Wildfire weapon: California aims to ignite 400,000 acres a year

After a long dry summer, the Santa Cruz Mountains were cool and damp on Friday morning, signaling the perfect time for crews to gather in an open meadow, drip torches in hand.

Their goal: fight fire with fire.

The blaze at Soquel Demonstration State Forest, part of the state’s ambitious new plan to ignite more small fires to prevent large ones, was only four acres in size, or 0.15% of the 2,681-acre wilderness. It was extinguished by nightfall.

But it’s taken 11 years to plan and 19 months to prepare, foreshadowing the challenge faced by the Golden State as it seeks to improve the health of forests and the safety of communities.

Friday’s strategy, part of a larger multi-phase plan at the site, will need to be repeated thousands of times to meet the state’s goal of burning 400,000 acres every year by 2025. Between 10 and 30 million acres of California’s landscape need some form of fuel reduction treatment — and burning is the most efficient approach.

“It is a start,” said forest ecologist Rob York of UC Berkeley. “But we still have a very long way to go before we can say that it is being used enough to make a difference at the ecosystem scale.”

For a century, California has kept wildfire out of its forests, snuffing out every spark. Now it’s playing catch-up.

This week a 300-acre burn was conducted on Wilder Ranch State Park, north of Santa Cruz. Last month, 20 acres were burned near Upper Crystal Springs Reservoir in San Mateo County. Sonoma County has held two recent burns, one in Pepperwood Preserve and another in Jack London State Historic Park, on the ridge above historic buildings.

Without careful preparation, burns can turn disastrous. Earlier this year, an escaped blaze in New Mexico scorched hundreds of structures, triggering new restrictions and a 90-day pause on all U.S. Forest Service prescribed burns.

But if done well, they work. When the explosive Caldor Fire reached the 2019 footprint of treated sites, the fire noticeably slowed, sparing South Lake Tahoe towns.

“Prescribed burning” is not a new concept. It was practiced by Native Americans for millennia to clear lands for hunting and return nutrients to the ground.

But the state’s Strategic Plan for Expanding the Use of Beneficial Fire, announced last March, aims to greatly expand its modern use by improving regulatory efficiency, expanding the workforce, covering some liability costs and other steps. The U.S. Forest Service also has a 10-year strategy to increase prescribed burns by four times the current levels in the West.

“Acreage targets cannot be reached without increasing the size of beneficial fire projects,” according to the state’s plan. “Projects that are currently tens or hundreds of acres must expand to encompass thousands of acres, when conditions are favorable.”

In the Soquel Demonstration State Forest, between Los Gatos and Santa Cruz, fire is long overdue.

Coastal redwood forests typically burn every 10 to 60 years, according to Matthew Mosher, an environmental scientist with Cal Fire’s San Mateo-Santa Cruz unit. But this forest hasn’t burned for over a century.

Routine burning — whether natural or lit by Native Americans  — came to an abrupt halt in the late 1800s when the region was home to the Sulfur Springs Resort, then commercial logging.

Now its canyons and ridges are blanketed by dense swaths of Douglas firs, tanbark oaks and redwoods.

The forest grows more flammable every day, as climate change brings hotter and drier conditions. The region has experienced six major fires over the past six decades, claiming dozens of homes.

Forest manager Angela Bernheisel began planning Friday’s fire, conducted by Cal Fire, soon after her arrival in 2011. It’s the first “unit” of a three-part 15-acre burn project.

“We would only burn once we could do it safely,” she said. “It’s the kickoff of a program that we’re implementing across the forest. We’re starting small… Our plan is have units that are prepared, ready to go, at least a few acres every year.”

To prepare, teams installed water tanks and completed road projects. They cleared underbrush to create “fuel breaks” that would help slow a runaway blaze. They thinned trees, pruned branches and chipped brush.

Experts surveyed the site, near a grassy helicopter landing pad, for evidence of any endangered species or archeological sites. They identified nearby creeks at risk of being clogged by ash. They studied the ground for signs of instability or erosion. Using computer models, they predicted a fire’s speed and intensity. How would smoke behave? To find out, they did an analysis.

As Friday approached, about 60 firefighters, five engines, a water tender and a bulldozer were recruited.

Weather cooperated, creating a window of opportunity that are ideal for two reasons, said York. While recent rains have dampened the soil, most plants are still dry enough to burn, he said. And more rain is on the way, not only lowering the risk that the fire will escape but also reducing the cost of patrolling the post-fire site.

As the sun rose, a “go/no-go” checklist was approved and a small “test burn” plot was ignited. Then the choreography began.

A scattered line of firefighters slowly walked across the landscape, their torches dropping fuel and fire onto brush. Dampness hindered ignition, creating patches of low flames that crawled along the forest floor. The blaze didn’t jump into tree canopies, or race out of control.

Watching from a distance, neighbors Ron and Patricia Marland were grateful for the effort but relieved it was well contained. “I appreciate that this happens periodically,” said Ron Marland, “because we don’t want to see the whole thing burned up.”

Research is revealing new ways to make future burns even safer, York said. Drones can do aerial ignition in unsafe conditions, dropping ping-pong-ball-sized spheres of fuel. Video cameras can detect dangerously flying embers. There’s improved understanding of seasonal patterns, showing how it may be safe to burn during a brief winter dry spell or on a cool summer night.

The effort, while small, is an important first step, said Joe Restaino, prescribed fire specialist with California Deparment of Forestry and Fire Protection.

“It’s not just about one project. It’s not just about one forest,” he said. “It’s about kind of readying ourselves for this journey, to be ready for more fire.”