Increased rain, vegetation set scene for wildfire season

By Ching Lee

Generous rainfall may have erased drought conditions for most of the state, but it has not necessarily eased concerns for a potentially aggressive fire season.

Saturated grounds and warming temperatures have spurred a bumper crop of vegetation across the landscape, particularly fast-growing grasses and invasive weeds that fuel wildfires when they turn brown. The wet spring may delay the start of California’s fire season, ecology and fire experts say, but it’s a matter of time before carpets of green become highly combustible if they are not managed.

“There’s a lot more vegetation this year, so people are very, very nervous about that as it starts to dry up,” said Andree Soares, a Merced County sheep and goat rancher who provides targeted grazing services for vegetation management.

Because the rainy season lasted longer this year, Soares said most of her animals were just deployed about two weeks ago. Bigger projects such as for the East Bay Municipal Utility District typically start in March but did not begin until last week. Depending on the project, her contract grazing work typically runs through September, sometimes into October.

The challenge this year, she said, is getting through all the vegetation, which she described as wetter, greener, longer and denser. With increased growth, it may take longer to graze each location. She said she’s also seeing different types of vegetation on the landscape—some long-dormant plants that are now coming to life.

Todd Lando, wildfire hazard mitigation specialist for the Central Marin Fire Department, said he expects the extra rainfall and snowpack will promote additional vegetation growth, leading to probably “one of the biggest grass crops of the last decade in California.”

With all the rain, he said he’s “really fearful that Californians are going to think that they somehow have a year off from wildfires. That’s just not the case.” A firefighter, forester and ecologist, Lando added, “I like to remind people that the 2017 fire season, which was devastating, followed an exceptionally wet winter in 2016.”

With more than 1.5 million acres burned and nearly 11,000 structures destroyed or damaged, the 2017 fire season was the most destructive in California at the time, according to Cal Fire. It was surpassed by the 2018 wildfire season, which saw nearly 2 million acres burned and more than 24,000 structures destroyed or damaged. Fueled by high winds and record-breaking heat, the 2020 wildfire year remains the state’s largest on record, with more than 4.3 million acres burned and more than 11,000 structures destroyed or damaged.

Lando said even though this fire season may start a little later, California’s Mediterranean climate and dry summers make the state prone to wildfires. In the coastal region, grasses are still green and growing, but that will change. “When we get into September and October each year, California is ready to burn,” he said.

As grasses dry out later in the summer, they become easy to ignite, and they can ignite other bigger fuels in their path, Lando said. He noted the “huge number of dead trees” from years of drought. Storms this year brought down more trees, with “an accumulation of dead vegetation on the ground like nothing we’ve ever seen before,” he said.

“Those factors all add up to the potential for a significant fire season this year and next,” Lando said, adding vegetation maintenance in open space and along roadways and evacuation routes remains “absolutely critical this year, maybe more so than ever.”

May marks the beginning of Wildfire Preparedness Week in California, and Len Nielson, Cal Fire staff chief for prescribed fire, said the live moisture content in the vegetation should allow more opportunities to do controlled burns to reduce fuels. It would help remove dead and dying vegetation without burning what’s green.

Nielson said Cal Fire’s goal is to reduce fuel on more than 100,000 acres a year. The department has met its goal during the past two years. So far this year, it has completed about 31,000 acres, with about 17,000 acres of broadcast burning and about 14,000 acres of thinning, pruning, mastication and fuel-break work.

Increased grant funding has played a “big part” in Cal Fire being able to achieve its goals, he said. Increased public interest in prescribed fire has also helped boost the department’s resources, he said, as private landowners form their own prescribed burn associations, get trained to become burn bosses and secure grant funding to conduct their own burn projects “with very little assistance from Cal Fire.”

But Nielson acknowledged that scheduling prescribed burns remains tricky. Cal Fire must still write the prescription, which predicts flame lengths, what direction the smoke will go and how much of the material vegetation will burn. Air temperature, wind speeds, relative humidity and fuel moisture must also be right. “When all of those are in alignment in our favor, then we can light the match,” he said.

With everything still “super wet” in higher elevations of the state, Tom Getts, University of California Cooperative Extension weed ecology and cropping systems advisor for Lassen, Modoc and Plumas-Sierra counties, said there’s “plenty of time” to reduce fuels, particularly in high-risk areas such as roadsides.

He noted many annual grasses in the intermountain region haven’t even started to head. Young plants can be treated with herbicide. Plants that are flowering can be mowed. But the best time to control annual grasses is in the fall before it rains and before weeds germinate, he said, noting there are pre-emergent herbicides that are safe on perennial species.

Grazing can help manage weeds such as cheatgrass, which is widespread in California. The invasive annual grass can be good forage for cattle early in the year when it’s coming out of the ground, but once it starts to head, animals don’t like to eat it, Getts said. Some grazing can also help control medusahead, but it’s another weed that’s not very palatable for animals.

Gett said this would be a good year for land managers to keep all weedy species from going to seed and becoming more prolific, especially in areas that have been impacted by wildfire.

“Weeds really have the ability to take advantage of that disturbance,” he said. “In the open landscape, there’s potential, especially in a year like this, for them to produce a lot of seeds and really gain more of a foothold.”

(Ching Lee is an assistant editor of Ag Alert. She may be contacted at clee@cfbf.com.)