With nearly 65,000 acres of open space preserves, the Midpeninsula Regional Open Space District carries some of the greatest burden — and potential — for preventing wildfires locally.

The district has had a fire-management plan for many years, but the big fires in northern California since 2017 and climate change have brought greater urgency to the district's fire-prevention efforts.

Now, the district's working on an expanded Fire Management Plan, which will include goals for public safety and ecosystem resilience against fires as well. The fire-management plan is one component of a new Wildland Fire Resiliency Program, which is currently being developed. The broader plan will address the protection of archaeological and biological resources, enhancement of environments for wildlife, public safety and education, the prioritization of areas for reducing fire risk, wildfire response training and other fire-management activities.

District staff said an expanded plan is necessary to effectively manage the open space amid growing wildfire concerns.

"A changing climate, 150 years of fire suppression and a growing population are combining to create a longer and more intense fire season in California. To meet these current challenges, Midpen Open Space is proactively expanding our environmentally sensitive fuels management," Midpen Senior Resource Specialist Jonathan "Coty" Sifuentes-Winter said in a July statement announcing the management-plan expansion and the new Wildland Fire Resiliency Program.

Midpen annually allows for management of vegetation on approximately 450 acres around district-owned and occupied buildings, fire breaks and helicopter landing zones. This year, the district expanded its vegetation removal by another 250 acres that local fire departments identified as high-priority, said Leigh Ann Gessner, spokeswoman for the district.

Crews are removing dead trees, dead limbs and shrubs and grasses in areas including Windy Hill, Pulgas Ridge and Bear Creek Redwoods preserves, among others. Last spring and summer, the district expanded its defensible space in Windy Hill Preserve around Hawthorns Mansion and near The Sequoias retirement community in Portola Valley and did maintenance work on an existing fuel break in Monte Bello Preserve along Page Mill Road.

The district is also focusing on evacuation corridors, populated areas adjacent to the preserves, residences and buildings within its preserves and critical infrastructure such as power lines and nearby medical facilities, according to the district's draft Fire Management Plan.

No more than 1,000 acres would be managed in a year and no more than 5,000 acres for every 10 years, mainly due to environmental concerns, including but not limited to modifying large tracts of habitat, air quality and noise pollution from use of machinery.

'All hands, all lands'

The district has hired Phillip Dye, owner of San Jose-based Prometheus Fire Consulting and a retired wildland firefighter, to gather data and recommend critical areas for clearing in its new plans.

On Nov. 14, Dye, with iPad in hand, hiked the 4.9-mile trail to Mindego Hill, a verdant mound of mixed forest and tawny grassland in Russian Ridge Open Space Preserve. Dye was on a mission to assess firefighter access, hazards and important features that would help responders if they must come into the area: the locations of roads, gates, water sources, existing fire breaks, homes, private roads and driveways and sensitive resources such as endangered species or archaeological sites.

Dye has been on the front lines of conflagrations many times, the kind that cover many square miles and in which flames can reach 40 feet or more into the air. He pointed to a stand of grasses about 18 inches tall surrounding one of the district's 42 helipads, where crews land when there are fires or medical emergencies. Crews can generally fight grassland flames, which might reach 4- to 8-feet tall, he said. But there's a far more insidious problem just a few hundred feet across Alpine Road, he said, pointing: a mix of dry grass and shrubs that's fertile ground for a fire with 20- to 40-foot-tall flames.

"That's too intense for fire resources to suppress," he said.

To manage the vegetation, Dye said he would recommend a pre-emptive burn of the shrubs to return the area to grassland and reduce the fuel load. The site is on private land, which Midpeninsula Open Space District doesn't control, but the district often works with property owners. Public-private partnerships are a necessary part of any strategy to reduce fire risk.

"The phrase I like to use is: 'All hands, all lands.' No one has the ability to do all of the work, but if we reach across fence lines, we can get more done," he said.

Heading down the steep Mindego trail, Dye looked for existing fire breaks — cleared areas that could slow or stop a fire's progress. Mowed areas along roadsides and trails can serve as such, but the Mindego trail won't be an effective fire deterrent, he said. Down-slope from the trail, a deep forest of trees and shrubby undergrowth provide ideal conditions for fire. And fire moves quickly uphill.

"If this road was trending on a ridge top, it would make a great fuel break, but this road is a mid-slope road. In a fire going up hill, the flames will be 20 to 30 feet high and will cut across the road. As a fire burns, it preheats the fuel in front of it, drying it out. When it gets to ignition temperature, it moves quickly," he said.

When fire reaches the top of a ridge however, it slows, so ridges with a road cut help to forestall a fire's advance. There's a caveat, however: If there are off-shore winds such as those in the October fires in Sonoma County, a 70 mph wind will still push a fire downhill, he said.

Coming to a small grove of conifers, the ground was littered with dead limbs and dry grass. Such areas in forests can create a "ladder" a fire can climb. Dye said he would recommend removing the vegetation as well as "midstory" trees — young saplings of a few feet tall that can enable a fire to reach into the tree canopy. Such fires, whipped by the wind, will spread from treetop to treetop and create embers that can travel long distances and start new fires.

Dye's work will inform the draft fire management plan and the overarching Wildland Fire Resiliency program. The expanded fire-management plan will go into new areas of the preserves and requires a new California Environmental Quality Act review, Gessner said.

A public meeting regarding the vegetation management portion of the program will take place at the district's office on Jan. 22, 2020, at 7 p.m., 330 Distel Circle, Los Altos. Sign-ups for notifications about the Wildland Fire Resiliency program and public input can be made at openspace.org/fire.

This article is part of a larger story on local fire agencies grappling with a new era of "megafires," which can be found here.

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• Weekly journalists discuss this issue on an episode of "Behind the Headlines," now available on our YouTube channel and podcast page.