PolitiFact – Sometimes trees stay standing after wildfires. That’s because of how the fire typically spreads

Deadly wildfires blazed a path of destruction across parts of Hawaii’s Maui, killing nearly 100 people and burning more than 2,000 acres. 

Hawaii Gov. Josh Green likened the charred-out scenes of disaster in coastal Lahaina to the aftermath of a bombing.

But online conspiracy theorists are going even further with the visuals — claiming the destruction was not complete enough to have been caused by a wildfire.

“This was no wildfire,” an unidentified narrator said in an Aug. 11 Facebook post. “A wildfire that demolishes buildings, leaving trees standing? Leaving restaurant umbrellas and trees untouched?”

Images flash showing blackened rubble and hazy smoke. A burned boat floats on the water.  Paint-stripped and windowless vehicles line streets and parking lots.

“What we are seeing here is definitely no wildfire,” the video narrator said. “Wildfires do not completely burn out cars, glass and all, yet leaving nearby trees and utility poles still standing upright.”

This post and others like it were flagged as part of Meta’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Meta, which owns Facebook and Instagram.) 

But wildfire experts said that claim is wrong. Numerous factors influence how and whether objects burn.

It is common for trees, utility poles and more isolated features to remain standing even as wildfires destroy other structures in the same area, experts told PolitiFact.

People walk along Main Street past wildfire damage on Aug. 11, 2023, in Lahaina, Hawaii. (AP)

“Cars have gasoline in fuel tanks and an enclosed space that retains heat, and buildings have enclosed spaces that allow heat to accumulate inside, leading to intense burnouts that last a long time,” said Lee Frelich, director of the University of Minnesota Center for Forest Ecology. “Also, if a window is broken or otherwise open, oxygen can flow into a hollow object like the inside of a car or building, supporting the fire.”

Fires spread three ways, through flame contact, radiation and firebrands, or flying hot embers, said Arnaud Trouvé, a University of Maryland professor and chair of the department of fire protection engineering. Fires that spread in the wildland urban interface — areas where structures and other human developments meet wildlands and vegetation — are often spread by firebrands. 

“Under those conditions, you can find patches of unburnt vegetation and structures,” Trouvé said. “When the fire spreads due to firebrands, fuel sources that are most vulnerable are structures, decks, fences, etc., that allow the accumulation of hot firebrands in their vicinity. Trees or poles are less vulnerable because the wind would blow the firebrands past them.”

Frelich said that structures such as trees and utility poles are less likely to be consumed by wildfire flames because heat can escape to the atmosphere, they are exposed to flames for less time than things in an enclosed space, and oxygen, which is needed for combustion, can reach only the outside of a solid wood object. 

“Most of the wood in trunks of standing trees — usually more than 90% — remains after even the most intense forest fires,” he said.

Destroyed homes and vehicles are seen in a neighborhood Aug. 13, 2023, in Lahaina, Hawaii, following a deadly wildfire that caused heavy damage days earlier. (AP)

When there is sufficient separation between a burning structure and vegetation, it is “very common” for the vegetation not to ignite, said Michael Gollner, a mechanical engineering professor at the University of California, Berkeley, who studies fire dynamics and wildland fires. 

“While flames can lick up to the side of a home or radiation can heat and ignite siding, 50% or more of the destruction is caused by flying embers,” Gollner said. “This makes it vitally important that you not only maintain vegetation around your home, but also that you ‘harden’ the exterior of your home with fire retardant siding, roofing, double-paned windows, fine mesh over vents, etc.”

Gollner also advised clearing flammable materials away from the first few feet around a home to reduce the risk of loss.

Frelich and Gollner said that the wildfire destruction on Maui resembled that of the 2018 Camp Fire in Northern California. 

“Most of the pines that sheltered this community still had their canopies intact,” the Los Angeles Times reported in that fire’s aftermath. “The needles, yellowed from the intense heat, were not burned — evidence that the winds that morning had pushed the fire along so fast it never had a chance to rise into the trees. But as a surface fire, it lit up the homes that lay in its path.”

A sign stands at a community destroyed by the Camp fire in Paradise, Calif. on Nov. 13, 2018. Most homes are gone, as are hundreds of shops and other buildings. (AP)

None of the wildfire experts PolitiFact consulted said they believed the damage in Hawaii was caused by anything other than a wildfire. 

Researchers are still working to identify what caused the wildfire in Hawaii, which often takes time when the fire continues to burn, said Joseph Wilkins, a Howard University professor of atmospheric science who researches wildland fires. It is likely “a standard case of too many invasive or non-native species of plants on the landscape, rising temperatures, and dry conditions.”

July 13, the Hawaii Department of Land and Natural Resources noted that much of Maui has experienced drought or has been abnormally dry.

Nearly 85% of wildfires in the U.S. are caused by humans, according to Wildland Fire Management Information.

Our ruling

A Facebook video claimed, “Wildfires do not completely burn out cars, glass and all, yet leaving nearby trees and utility poles still standing upright.”

Wildfire experts told PolitiFact it is common for trees, utility poles and more isolated features to remain standing even as wildfires destroy other structures in the same area.

We rate this claim False.

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