The Marin Post

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modified after Pg&E by NiccoloCaldararo

Study Finds Defensive Space Useless


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We have a problem in local government, the idea of "wildfire prevention." Having written several studies on the subject and a review of the archaeological history of human created fire environments, I think this idea needs review.

Lorenzo Morotti reports on the dilemma Mill Valley residents and city officials have been put in by the current dogmatic form this idea. The idea of creating "defensible space" is an unscientific and unproven idea. A recent review of fires in California by Syphard and Keeley (2013) came to the conclusion about defensible space:

"The relative importance of defensible space, as quantified by deviance explained in the regression models, was virtually nil statewide...,"

Fire histories show that fire spreads largely due to terrain, type of housing material, weather conditions (heat and wind primarily), and the speed at which the fire produces its own velocity conditions. The type of fire, given heat of the fire and wind, can shower embers over considerable distances.

During the Oakland fire in the 1990s, fragments of peoples' books from Oakland homes fell in San Francisco, demonstrating how far debris can be sent. Hot embers can ignite flammable materials and when driven by heated winds can produce a rain of combustion than can leap across any space. It only encourages people to stay in their homes endangering their lives when they have been certified to have created defensible space. The only way to guarantee fire will not travel is to create a desert.

In a related issue, a recent front page story concerning the Big Basin Redwoods' recovery from fire damage in the IJ by Paul Rogers on April 24th 2021, reports on efforts to restore the park. We should recognize that most wild fires, over 80%, are the result of human activity, most by actual ignition or accident.

Human presence is associated with frequency of wild fire. Recreation increases the probability of wild fire and building in the urban/ wild land interface is one of the most dangerous factors in damage and human loss of life due to wild fire.

Destroyed recreational facilities in the parks should not be replaced. Rather human activities should be curtailed if we want to reduce the cost of fighting fires. Encouraging animal populations that feed off wild land plants is the most efficient way of preventing fires. Drought will reduce plant growth and thus reduce biomass for burning. Current practices of reducing forest and brush from areas around human activities (recreation and logging) have produced piles of dead trees and brush that are ignition problems. Planned fires, often called prescribed burns, are not effective as they only continue a long tradition of making forests and wild lands fire-adapted ecologies.

Syphard, Alexandra and Jon E. Keeley, (2019) "Factors associated with structure 2013-2018 California wildfires," Fire, volume 2: doi:10.3390/fire2030049

See:

https://www.mdpi.com/2571-6255/2/3/49

https://www.mdpi.com/2571-6255/4/1/12/htm

Tags

defensive space; wildfire; conservation; gardens