Wildlands that burned may find that nature heals itself

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Inmates from California’s prisoner firefighter program coil hose along a charred hillside. Photo by Michael Nigro/Sipa USA

When wildfires traveled down from the brush toward homes in the Palisades and Altadena, they left a wide scar not only in the built environment, but the natural landscape too. When will those areas look green again? KCRW sits down with experts at TreePeople to get some answers.

What is the timeline for restoration?

The first step is for the experts to just stay hands-off and watch what happens. These fires are still active, and it remains unsafe to return to many areas. But even after the fires are out, biologists will observe how burn areas recover naturally. 

The main concern is a phenomenon called “type conversion” where invasive species supplant native ones. Unlike native species that are adapted to wildfires, invasive vegetation can increase fire danger. Where that happens, conservationists will go to work planting and reseeding. 

The experts at TreePeople are hopeful that nature would heal itself, saying that many affected areas show high levels of resiliency. Alyssa Walker, associate director of conservation at TreePeople, says that after the Lake Fire burned Angeles National Forest in 2020, “I went back out there shortly after to do some surveying, and we saw immediately a handful of species that were already resprouting … within a month of the fire, with very little precipitation.”

Walker explains that because LA experienced two wet winters in a row, the vegetation grew fast, and, in turn, released seeds into the soil. In fact, some of those dormant seeds are heat activated and require a burn to germinate, so those plants will start sprouting right away. 

Things will grow, but there’s no solid timeline. It all depends on precipitation.

In the case that TreePeople intervenes, what areas would be prioritized?

Areas with a lot of public access, such as Will Rogers State Park. Because of the presence of people, these spaces pose an increased wildfire risk. 

LA is forecasted to finally get some rainfall. Is that going to be a reprieve from dangerous fire weather – or present a further danger because of mudslides?

While mudslides are always a concern when burn areas experience rain, the experts remain optimistic. Much of the vegetation that burned had robust root structures, which remain even if the trunks have burned. The roots of certain chaparral species, and trees like coastal oaks and laurel sumac, are especially well-positioned to resist sliding. 

However, some preliminary research indicates when chaparral biomes burn they can release oils into the soil which make it unable to absorb water, increasing flood risk.

There are lots of images of the Palisades and Eaton Fire areas showing houses totally ravaged while the hedges and trees surrounding properties remain standing. Why didn’t that vegetation burn? 

Unlike manmade structures, trees have water coursing through them, naturally increasing their fire resistance. 

Take oak trees in particular; these have evolved to resist wildfires. With thick bark, high water content, and waxy leaves, they’re unlikely to burn. 

In fact, oaks can actually help protect houses from burning when they’re planted nearby.

The common misconception is that houses burn when the fire line reaches them, but in reality, embers travel miles ahead on the wind. When they land on vulnerable parts of a house, like dryer vents or gutters, they spark fires. Oaks can stop embers from reaching a house and decrease the chance of combustion. Embers caught by the trees fail to ignite, decreasing the likelihood of a structure combusting.

Home hardening has been part of the conversation about wildlife resiliency moving forward. Doesn’t this contradict the advice? Plant more trees around your house?

It’s only certain plants, not that all plants are useful. Oaks are a fire-tolerant native species. And they’re not preventing houses from burning down overall, just decreasing the likelihood of ignition from an ember-storm. But yes, according to the experts, a line of fire-resistant trees north or northeast of a structure does decrease the chance of burning.

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Reporter:

Tohar Zamir