Invasive grass - the culprit that made the Hawaii fire storm stronger

Grasses native to Africa are rampant in Hawaii, withering in the summer and becoming a factor in the spread of fire.

Houses, buildings and harbor in the town of Lahaina were burned on August 10. Photo: Patrick T. Fallon/ AFP

Wildfires on the island of Maui, Hawaii, have ravaged the tourist town of Lahaina, damaged thousands of structures and killed at least 110 people so far. Researchers are still analyzing the cause of the fire, including one factor that makes the fire more deadly: invasive grass, Smithsonian reported on August 16.

For nearly 200 years, the Hawaiian economy was heavily dependent on sugarcane and pineapple cultivation. But by the 1990s, planted acreage began to decline as the state transitioned to tourism-led, according to the New York Times. Many large farming areas were abandoned. In 2016, Hawaii's last sugarcane farm closed.

With no farmers tending to the soil, non-native grasses such as guinea, honeysuckle and buffel spread. These species originated in Africa and were brought to Hawaii by European ranchers in the late 18th century for a stable and drought-tolerant forage source. Today, they occur on nearly a quarter of the land area of ​​Hawaii. Lively, greedy and opportunistic, they flourish in what used to be sugarcane and pineapple farms, encroaching on roadsides and urban housing estates.

"These flammable invasive species will fill any void everywhere - by the roadside, between communities, between people's homes, everywhere," said Elizabeth Pickett, co-executive director at The Governing Foundation. Hawaii Wildfire Manager, said.

Cows graze on land that used to grow sugar cane in Hawaii. Photo: Bonnie Jo Mount/The Washington Post

Invasive weeds spread during the rainy season and wither during drought. At a time like this summer, their dry state makes them very flammable. After the fire swept through, many species adapted to recover quickly, becoming the first to repopulate the scorched land, crowding out native plants. This "grass-fire" cycle causes invasive weeds to grow more abundantly after a fire, making subsequent lands even more flammable.

Scientists have long known about the flammability of invasive species. In 2018, fire broke out in West Maui and destroyed 21 homes, in part due to them. Researchers estimate that 85% of the area burned in 2018 was the land of non-native trees. After the disaster, one of Maui's most famous fire experts, plant ecologist Clay Trauernicht at the University of Hawaii, warned the grass could spark future problems. In 2021, a report by the Maui government also warned of rampant shrub growth and called for their control.