Damp spoils prescribed burn

11/20/2019

Damp weather cut short the first prescribed burn in the Point Reyes National Seashore since 2015 last week: Just 20 acres of a planned 205-acre area between Olema and Bolinas were ignited before fire managers with the National Park Service called it quits.

“We do plan on looking at future windows to get back in and resume burning,” said Gregory Jones, the fire management officer for national parks in the Bay Area. “The fog was going to come in even more, so it just made sense to say, ‘Hey, we’ve made good progress, let’s stop here.’”

The intended burn zone consisted of four areas east of Highway 1 between Olema and Bolinas. Beyond creating a strategic fuel break, the burn aimed to remove invasive French broom and maintain open grasslands between large areas of dense forest at the base of the Bolinas Ridge. The plan was to burn for about five days, but fire personnel stopped after one.

The area was last burned in 2015.

Only one other burn is planned for this year: a pile burn on the Inverness Ridge. The stacks of tree branches and trunks are a byproduct of a multi-year forest thinning project. When the area is moist enough to keep the surrounding forest floor safe, firefighters will ignite the piles’ dry cores.

The park service’s fire management plan, which dates back to 2004, allows for up to 2,000 acres of prescribed burning and 1,500 acres of mechanical treatment annually within the seashore and the northern reaches of the Golden Gate National Recreation Area.

But with just 20 acres burned in the last four years, the seashore has fallen well short of these limits. Mr. Jones said that is due to a variety of factors: the availability of resources, the absence of a solidified long-term strategy, and sensitivity to concerns about air quality and wildfire. 

“In general, folks are nervous about the risk, whether from wildfires or prescribed burns,” he said. “It is up to land management agencies and fire agencies to do our due diligence and public education on how a prescribed fire can be an effective tool.” 

In the Olema Valley, fire management staff is getting closer to an appropriate burn rotation, Mr. Jones said. But other areas, such as the bishop pine forest on the Inverness Ridge, require further effort and planning. Part of that area burned in the 1995 Vision Fire, sprouting an abundance of young trees, many of which are now infected with a fungus. Dead branches and trees have accumulated in the thick forest.

The park service prefers mechanical treatment on the ridge. “Right now, I think that’s a more appropriate tool for us to use, especially adjacent to the community,” Mr. Jones said. “That doesn’t mean we won’t do burns there in the future, but for the short term we’re focusing on mechanical treatment.”

The 2004 fire management plan, which was intended to guide the park service’s fire management program for 10 to 15 years, both acknowledges and places constraints on the park when it comes to prescribed burns. 

First, the plan does not allow prescribed burns to continue through the night. Because burns have to be secured by dusk, large-scale burns are not possible. Smaller burns require more time for fewer acres, driving up the cost per acre. 

Second, the plan requires that all prescribed burns have contingency resources, such as fire trucks on standby, based on a worst-case scenario. “This is further complicated by the fact that the fire season peaks around the nation in the summer months, and resources that are normally used for conducting prescribed burns may be needed in another location for emergency fire suppression,” the plan states.

The burn windows throughout the park vary. The Olema Valley can generally support fire any time after its grasses have cured, which tends to happen in early summer. The Inverness Ridge can only support burns in a narrow window, from late September until there is a pattern of rain. The shrubs and trees on the ridge take longer to dry than grasses and are also kept moist by summer fog.

Finally, fire mangers must plan around a significant population of unique or threatened wildlife. “Avoiding these sensitive resources can result in burn units  that are not optimally laid out,” the plan states.