How invasive grass swaths made Maui's fires so devastating

How invasive grass swaths made Maui's fires so devastating

On August 10, homes, buildings and the harbor in Lahaina burned to the ground after wildfires swept through the Maui area.
Patrick T. Fallon/AFP via Getty Images

Researchers are still searching for answers about what caused last week's fires on Maui that have claimed at least 99 lives so far and destroyed the historic tourist town of Lahaina. However, investigators know one factor that made the fires so deadly: an invasive grass that turned the island into a giant powder box.

For nearly 200 years, Hawaii's economy was based largely on the cultivation of sugar cane and pineapple. But farms began to decline in the 1990s as the state transitioned to a tourism-dominated economy, Simon Romero and Serge F. Kovaleski reported for The New York Times. Large swaths of farmland were abandoned, and in 2016, Hawaii's last sugarcane plantation closed.

Without farmers taking care of the land, non-native brush such as guinea grass, molasses grass and buffalo grass moved in. This species is native to Africa and was introduced to Hawaii in the late 1700s by European ranchers who wanted a steady supply of drought-resistant cattle. Fodder. Today, nearly a quarter of Hawaii's land cover consists of these invasive shrubs. They are running amok on tens of thousands of acres of plantations where sugarcane and pineapple plants once flourished. They are aggressive, voracious and opportunistic, invading roadsides and encroaching on urban residential areas.

“These fire-prone invasive species fill gaps elsewhere — on roadsides, between communities, between people's homes, everywhere,” says Elizabeth Pickett, co-executive director of the Hawaii Wildfire Management Organization. WiredSimon died.

Non-native grasses spread easily during the rainy season and dry up during dry periods. At a time like this summer, when the landscape is barren, the dried and dormant state of the plants makes them highly flammable. After a fire ignites, some of these species adapt to recover quickly and, as a result, are the first to repopulate burned land, crowding out native plants as they reproduce. This “grass fire cycle” makes invasive grasses more prevalent after a fire, leaving the land more vulnerable to another fire, Scott Dance and Kate Seelig write in the journal Washington Post.

Scientists have long known about the burning potential of this invasive species. In 2018, fires ripped through West Maui and destroyed 21 homes, thanks in part to these weeds. 85% of the areas destroyed in the 2018 fire were non-native shrublands, researchers estimate. mail. After that disaster, one of the island's leading fire experts, University of Hawaii plant ecologist Clay Traurnicht, posted a letter asserting that “all that grass” could fuel future incidents. In 2021, a Maui County report also warned of the shrubs' proliferation and called for their reduction.

Now, five years after that devastating event, history is repeating itself.

Making matters worse today is a confluence of weather patterns creating a perfect storm of fire danger. For example, Hawaii is experiencing a dry season, with more than a third of Maui County facing drought. Second, 80 mph winds swept across the island, fanning the flames of the Maui fires. These strong winds were likely caused in part by Hurricane Dora, which passed through the state in the Pacific Ocean last week.

Although the storm originated about 500 miles off the island's coast, it created a pocket of low pressure that contrasted sharply with an area of ​​high pressure from another storm north of Hawaii. This sparked southward-moving high-speed gusts that strengthened the fire's advance.

It also doesn't help that wind sucks moisture from the plants it touches, further drying out the landscape and exacerbating dangerous conditions where fires can spread.

Low precipitation and thin cloud cover — combined with high temperatures in today's era of global warming — make wildfires on a tropical island like Hawaii not just a possibility, but a possibility. Experts say wildfires will become more common unless local officials take action to mitigate fire risks.

Do not tell me Spectrum NewsA good first step to mitigating fires is to reduce the fuel needed for future fires, said Michelle Bruder-Van Dijk. This means returning invasive farms to tended farmland. Grazing animals can also be valuable allies in eliminating these invasive weeds. This method is as simple as letting the sheep, cows or goats do what they do best in grass-dominated spaces, so they can trim back unruly rake.

Furthermore, fire breaks, or gaps between flammable plants, can help contain a fire once it breaks out. Rather than allowing fires to spread unfettered over grasslands, Trawernicht recommends planting rows of pineapples, bananas, dragon fruit or taro to cut off a potential fire's spread path.

“Just as with climate change, we know what steps will reduce the risk of wildfires,” Trawernicht wrote in his 2018 letter. “But actually taking these steps will require reinvesting and, frankly, reimagining our individual and collective responsibility to the larger landscape.”

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