Richard Halstead
The Marin Independent Journal, Novato, Calif.
(TNS)

Feb. 19—A prescribed burn on Mount Tamalpais planned for this month — the first one in years — was postponed because of wetter-than-expected conditions, and it is now uncertain if it will take place any time soon.

The Marin Municipal Water District’s Biodiversity, Fire and Fuels Integrated Plan, completed in 2019, called for prescribed burning on 450 acres of grasslands, oak woodlands and possibly chaparral within five years of the plan’s adoption.

But Adriane Mertens, a spokesperson for the district, said the district has been unable to complete any prescribed burns since 2019.

“It has taken time to develop a prescribed burn plan,” Martens said. “There are many requirements that must be in place to ensure compliance with state regulations. Additionally, Marin Water does not have the authority to actually implement a prescribed fire and does rely on Marin County Fire and the availability of its resources to implement the burn.”

There is widespread agreement that more prescribed burning is needed in Marin to reduce fire fuel loads that have been accumulating for decades because of fire suppression. Myriad conditions — including favorable weather, air quality, wind speed and direction, and firefighter availability — must align before the burns can take place.

At the request of the water district, the Marin County Fire Department was prepared to conduct a prescribed burn in the Rock Springs area of Mount Tamalpais on Wednesday and Thursday. The plan was to burn up to 27 acres of overgrown vegetation between Stinson Beach and Mill Valley on the southwestern edge of the Mount Tamalpais watershed.

“The conditions weren’t quite dry enough, especially on the northern slopes,” said Chris Martinelli, the county’s deputy fire chief. “It’s tricky this time of year with the windows between rains making sure things are dry enough.”

If fire fuels are too wet, they might only partially burn and produce excessive smoke.

Martinelli said it is hard to say now when the burn might take place. He said the coming week is not possible because the “burn boss” is off duty. The first Wednesday and Thursday of March is a possibility, but the forecast could call for more rain, Martinelli said. After that, there are bird nesting seasons to contend with.

“A lot of pieces have to come together,” he said.

The Marin County Fire Department issued 238 burn permits from 2018-19 to 2022-23. Martinelli said the majority of the permits were for pile burning, during which vegetative material is stacked in piles and burned onsite rather than hauled offsite for disposal.

By contrast, prescribed or broadcast burning involves burning a well-defined area with discrete boundaries to reduce fuel load and improve habitat.

Martinelli said that during years when there are many large wildfires, state fire officials prohibit all burning. In 2021-23, only 27 burn permits were issued in the county.

MMWD’s 2019 fire and fuels plan also noted that it is difficult to get the firefighters needed to conduct prescribed burns if local crews are being dispatched to help fight wildfires in other areas.

Martinelli estimated that 25 firefighters would have been involved in the prescribed burn planned for recent days. Some of the firefighters would have been required to monitor the site overnight to ensure the fire didn’t reignite.

In February 2022, a 1.5-acre prescribed burn at Audubon Canyon Ranch’s Martin Griffin Preserve near Stinson Beach escaped its intended perimeter after winds picked up during the night. The fire was conducted by Fire Forward, an Audubon Canyon Ranch program that trains community members how to perform prescribed burns. The county fire department, which hadn’t planned to participate in the burn, extinguished the fire.

Wendy Coy, a representative of Audubon Canyon Ranch, said the fire remained well within the boundaries of the nonprofit’s preserve and threatened no homes. Coy said Fast Forward now either has personnel remain at burn sites overnight or checks on sites every couple of hours throughout the night.

The water district’s 2019 fire and fuels plan also identified more stringent air quality protection measures as one of the factors making prescribed burning difficult.

“We have a smoke management plan approval process for prescribed burning,” said Patrick Wenzinger, an air quality specialist with the Bay Area Air Quality Management District.

Wenzinger said anyone seeking to do a prescribed burn must submit a smoke management plan to the district at least 30 days before the event.

“We review that plan,” Wenzinger said, “to ensure that prescribed burns are conducted during specific meteorological conditions that achieve favorable smoke dispersion and limit negative impacts to surrounding communities.”

The plans include a number of specifications: relative humidity, temperature, wind speed, wind direction and “mixing height,” which is the height to which a pollutant such as smoke can be dispersed.

After getting its smoke management plan approved, the entity seeking to do the burn must check in with the air quality district to get the final go-ahead the day before it wants to burn.

Wenzinger says the district decides whether to give the green light and how much material to allow to be burned based on the meteorological conditions and the amount of pollution in the air at that time. He said the district also has to factor in how many different entities are seeking to do burns at the same time.

Despite its many prerequisites, Wenzinger said the district wants to encourage prescribed burning to help reduce fuel loads. In 2019, it waived its fee for public agencies to do prescribed burning.

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