The new risk of wildfires in the United States goes beyond the forests | ET REALITY


Wildfires may get more attention, but a new study reveals that grassland fires are more widespread and destructive across the United States. Almost every year since 1990, the study found, grass and bush fires have burned more land than wildfires, and they have also destroyed more homes.

But many residents are not as aware of the risk of wildfires in grasslands and bushland.

When the Marshall Fire tore through suburban Boulder in 2021, killing two people and incinerating more than 1,000 homes, many residents were shocked that such a ferocious fire could encroach on their community, far from the forests of the Rocky Mountains.

In reality, the community’s risk was high: many homes were near wide expanses of tall, dry grass that were primed to burn. When a grass fire broke out, strong winter winds blew it into nearby neighborhoods where flames easily jumped from grass to homes, sometimes using the wooden fence that separated human and natural landscapes as a springboard.

A resident affected by the fire told investigators It was “a wake-up call” about the risks of grassland fires.

Volker Radeloff, a professor of forest ecology at the University of Wisconsin-Madison, who led the new study, pointed to both the Marshall Fire and the recent Lahaina Fire in Hawaii as two extreme examples of the risks that wildfires can pose outside of Hawaii. the forests. Both began with the burning of grasses and became devastating urban infernos.

Wildfire risk to homes is especially high in areas where the built environment meets wild vegetation, Dr. Radeloff said, a region called “the wildland-urban interface,” or WUI for short (pronounced WOO- ee).

The new study found that wildfire risk increased across the United States in recent decades, but was highest in WUI areas. These include places like suburban Boulder, where neighborhoods border wild vegetation, as well as areas where individual homes are surrounded by nature.

Over the past 30 years, the number of people living in these fire-prone areas has increased significantly as demand for more housing has skyrocketed, including affordable alternatives to city living and many second homes. At the same time, a confluence of factors, including temperature amplified by climate change and historic wildfire overheating, has increased the risks of large wildfires in many parts of the country.

The new study, published on thursday in Science magazine, shows how the problem of forest fires in the country reaches beyond the West and beyond the forests.

Nearly two-thirds of wildfires in the United States between 1990 and 2020 burned in grasslands and shrublands, the study found. Because fires in these areas were much more common, they also destroyed many more homes than wildfires.

Grass fires and forest fires differ in important ways. Forests have more fuel, so they tend to burn more intensely, meaning that any individual forest fire is likely to be more destructive than a grass or bush fire. A wildfire can also shed embers that ignite new fires far from their original boundaries.

But grass fires can spread more quickly across a landscape when the wind picks up, giving communities less time to respond.

Like wildfires, the frequency of grass and bush fires has increased over time.

Victoria Donovan, who studies fires in grassland and savanna systems at the University of Florida and was not involved in the new study, said more research is needed to fully understand the reasons behind the increase, but a warming climate, encroachment of woody vegetation and the introduction of non-native species has played a role.

Decades of suppression of lower-intensity wildfires have also increased the risk of larger, more destructive fires in many grassland ecosystems.

“Fire suppression of many of these systems has actually increased wildfire risks due to fuel buildup,” Dr. Donovan said. “That’s a major problem.”

Because many grasslands, bushlands and forests really need Although burning is necessary from time to time to remove pests and the buildup of old, unwanted vegetation, prescribed burns have become an increasingly important tool for wildfire management.

The practice of starting smaller, controlled fires to prevent larger fires, long practiced by indigenous peoples, has sparked new interest among forest managers in Western states. In grassland systems, such as the Great Plains, where more land is privately owned, individual landowners are coming together more and more to share knowledge on prescribed burns. Some also use grass to help reduce the risk of fire.

Recognizing that more frequent wildfires are a new reality, some states and localities have passed laws targeting new construction in wildfire-prone areas. In 2008, California adopted some of the strictest standards in the country, requiring new homes built in high-risk areas to use fire-resistant materials. Homes built in the state after 2008 are more likely to survive a large forest fire. Boulder County expanded local building codes last year to require ignition-resistant building materials for new buildings throughout the area, and Colorado set out to create a statewide wildfire building code by mid-2025.

For individual homeowners, many of the strategies for protecting homes from fire are the same in forests, grasslands and bushland, including creating a buffer zone free of vegetation.defensible space”, which covers entry points into homes, such as vents, and retrofits roofs and windows with fire-resistant models.

Most importantly, experts said, people should know their area’s fire risk and prepare by creating a solid evacuation plan.

Especially if you live in a fire-prone WUIsaid Dr. Radeloff, “we must assume that the question is when, not if,” the fire will occur.

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