How Does a Rainforest Catch Fire?

Characterized by high levels of rainfall – it seems peculiar that a massive fire could take root in a rainforest region. That is why understanding exactly how and why Brazil’s Amazonian rainforest was set ablaze is particularly important.

A majority of the Amazon rainforest occurs within the Brazilian states of Amazonas and Pará. The Amazonas state remains largely inaccessible and holds the largest tracts of pristine forest. But in Pará, roads have made the state vulnerable to deforestation.

“Many of the current fires are along the north-south Cuiabá-Santarém ‘Highway’ (BR-163) which bisects the western half of Pará state, while other fires follow the east-west Trans-Amazonica ‘Highway’ (BR-230) – which follows the northern rim of the Brazilian shield just south of the Amazon River floodplain,” explains Mark Sabaj, PhD, interim curator of fishes at the Academy of Natural Sciences of Drexel University. 

Photo by Mark Sabaj/ANS

A frequent visitor to South America, Sabaj explains that loggers looking to extract timber from the rainforest will clear secondary roads that run perpendicular to the Trans Amazonica Highway. After the large valuable trees are removed, fires are used to clear the remaining brush, creating open pasture for cattle.

“The scattered trees that escape logging are often killed by the fires but remain standing as lonely tombstones of the deceased rainforest,” said Sabaj. “In Pará state over 8,761 fires have been recorded for this August, which is well above last year’s August (2,782), but well below the record high of 23,635 set in August 2005.”

In fact, deforestation from fires in the first weeks of August, the start of the dry season, is more than 80% higher than over the same period last year,” explains Richard McCourt, PhD, associate curator of botany at the Academy of Natural Sciences and professor in the College of Arts and Sciences. In an opinion piece for The Philadelphia Inquirer, McCourt said it is unknown and untold the numbers of species of trees, insects, frogs and birds losing their homes and perishing in the flames.

White-crowned Manakin. Photo by Jason Weckstein/ANS

“One huge problem with this is that although the entire Amazon Basin is not burning, the biodiversity in the basin is not uniform, meaning there are distinct areas of endemism that have unique assemblages of species and some of these unique areas are being heavily hit by agricultural practices and these fires,” said Jason Weckstein, PhD, associate curator of ornithology at the Academy of Natural Sciences and associate professor in the College of Arts and Sciences.

Photo by Mark Sabaj/ANS

Weckstein notes that Brazil’s current president, Jair Bolsonaro, has severely cut funding for the public body, known as IBAMA, the governmental wing that protects forests and biodiversity. IBAMA’s budget has shrunk by 25 percent since Bolsonaro took office on January 1 – with funding for prevention and control of forest fires seeing a reduction of 23 percent.

Tuesday, the Brazilian leader announced his government will accept all foreign aid from organizations and countries to fight the wildfires in the Amazon, a day after he had rejected a proposed aid package from G-7 countries totaling $22 million.

The catch is all aid will be accepted, as long as the Brazilian government can decide how to use the funds.


By Emily Storz

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