• Matt Simmons

Science Roundup: Wildfire

Wildfire season is fast approaching. So, we thought we’d take a look at some recent scientific articles that studied the causes and effects of wildfires in order to better understand these events.

What do you think occurs more frequently: a fire igniting on forest service land and burning down nearby towns or a fire igniting on private lands and spreading onto forest service lands?

Downing et al. (2022)[1] analyzed the ignition sources for all cross-boundary fires that burned through forest service lands from 1992 to 2019. A cross boundary fire is a fire that ignites on one land ownership but spreads to another. Researchers found that 11% of USFS fires were cross boundary fires and that most cross boundary ignitions were human-caused (e.g., debris burning, equipment use, escaped campfires) and originated on private lands.

Public lands managed by the US Forest Service were not the primary source of fires that destroyed the most structures. Cross‐boundary fire activity peaked in moderately populated landscapes with dense road and jurisdictional boundary networks. That means that if we develop more and more in the wildland urban interface (WUI) we will likely increase the frequency of cross boundary fires caused by human activity.

What kind of land management do you think is correlated with more severe wildfires?

Levine et al. (2022)[2] categorized 154 California wildfires based on how severely they burned and the ownership of the lands they burned through. The researchers found that the chance of a fire burning at high severity was 1.8 times higher on industrially managed private timber lands than on public lands. The researchers also found that lands adjacent to private industrial timberlands were also more at risk of experiencing high severity wildfires than lands further from private industrial timberlands.

The researchers concluded “[t]he clear relationship between private forest management and increased high-severity fire suggests that forest manage- ment practices on private industrial land within our study area contribute to increased fire severity, possibly through the creation of continuous forest-fuel structures (eg younger, even-aged forests).”

How effective do you think our fire suppression and megafire prevention strategies have been in recent years?

In DellaSala et al. 2022[3] researchers have martialed reams of scientific analysis in order to argue that our current wildfire fighting paradigm is harmful, ineffective, and costly. First the researchers have gathered numerous studies on the harmful effects of wildfire fighting activities. Thousands of miles of dozer lines, which disturb habitats and introduce invasive species, and millions of gallons of toxic fire retardant are deployed each year. And yet, studies, which DellaSala and his colleagues gathered in this review, have repeatedly shown that these efforts are often ineffective. Instead of trying to fight and control wildfire, the researchers argue that we should learn to coexist with it as a natural part of our ecosystems, especially in areas far from populated areas. In the past, pro-management researchers have accused DellaSala and his colleagues of “agenda driven research” for advocating for a more hands off response. The researchers respond that our current approach has clearly been shown not to work and that we can’t log our way out of climate change induced drought and wildfire.

[1] Downing, William M., et al. "Human ignitions on private lands drive USFS cross-boundary wildfire transmission and community impacts in the western US." Scientific reports 12.1 (2022): 1-14. [2] Levine, Jacob I., et al. "Higher incidence of high‐severity fire in and near industrially managed forests." Frontiers in Ecology and the Environment (2022). [3] DellaSala, Dominick A., et al. "Have western USA fire suppression and megafire active management approaches become a contemporary Sisyphus?." Biological Conservation268 (2022): 109499.