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Burned areas of the Amazon can take centuries to fully recover
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The Brazilian Amazon continues to burn. While international leaders call for action and Brazilian military attempts to fight the flames, researchers have begun to warn that if the wave fires continue to spread in the forest, the flames can cause a huge transformation in the region. The process can once turn humid jungles into dry wastelands, kill old trees, make them more vulnerable to future fires, and release carbon trapped in the air for millennia.

It is still unclear how much damage the tens of thousands of recent fires, most of which have been linked to a peak in break through deforestation, will eventually cause. Decades of research, however, provide a picture of what can happen next. When the Amazon burns, the consequences are often devastating because the ecosystem has developed without fire for millions of years. Amazon trees simply lack the necessary adjustments to survive the heat, says Ane Alencar, a geographer at the Amazon Environmental Research Institute in Brasilia.

Previous studies conducted near the city of Manaus, in the heart of the Amazon, have shown that when some areas are felled but not burned, fast-growing trees with large leaves branching out like a candlestick that begins to appear, provides shade and cools the air. Over time, some of the plants that originally occupied the land may grow back from surviving sprouts or seeds buried in the ground or brought by visiting birds and other animals.


A fire burns through a forest reserve in Monte Dourado in the state of Pará in 2004.
Photograph by Jos Barlow

The resulting environment is dark and damp. "It looks more like a forest," says Emilio Bruna, a tropical biologist and director of the Florida-Brazil Linkage Institute at the University of Florida.

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Scorched forests do not recover that easily. A few years after a fire burns through an area of ​​the Amazon, lush vegetation is often replaced by one dense piece of skinny trees that occupy most of the space. The flames can also kill the seeds of other species and scientists have found that many birds tend to stay away. "You walk into a burnt area and you notice it is brighter, it is hotter and it just feels drier," says Jos Barlow, an ecologist at Lancaster University in Lancashire, England. Barlow started working in the Brazilian Amazon in 1998, a time when the smoke and flames of forest fires shut off airports, caused hospital admissions, caused blackouts, and cost the country $ 5 billion in damage.

Earlier this year, an international team looked at 56 locations across 10 countries in North and South America to study how these tropical forests, both burnt and unburned, grow over time. The results of the investigation suggest that they can recover about 80 percent of the tree species they have lost within 20 years. "The point is that (50) years later you still don't have a regenerated Amazon forest," Bruna explains. Although after half a century the number of tree species is the same as before, the study concludes, centuries will have to pass until the abundance of those species is back to normal.

Even after regrowth, the effects of fires can be long lasting.

In the years following a fire in the Amazon, the larger trees – some of which may be 1000 years old – begin to die. The causes are varied, according to Barlow. Some of the roots and trunks that normally hold the trees in place may be damaged, making them more vulnerable to being thrown by the wind. The flames can also open them up to diseases, allowing pathogens and termites to penetrate.

"You have taken thousands of thousands of years of carbon accumulation, you have evaporated it and you have released it into the atmosphere," Bruna explains. "You won't have an equivalent rainforest for hundreds of years. And those are hundreds of years that we don't have."

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For example, in 2018 a group of Brazilian scientists discovered that once burned forests in the Amazon contain 25 percent less carbon than forests that were not set on fire, even after 31 years of renewed growth.

The record fires in the Amazon have caused great concern in the scientific community of Brazil. "I'm really afraid we're going back to the 90s. Those were very difficult years," says Alencar, who witnessed the effects of the fire at the time. "Brazil lost a lot in that period."


In November 2015, flames burn through the overgrown forest in Santarém during an intense drought in El Niño.
Photograph by Jos Barlow

What happens next ultimately depends on how the Brazilian government chooses to respond.

In an attempt to put out the fires, the government of President Jair Bolsonaro signed a national decree of 60 days on 28 August prohibiting people from lighting the forest. But some are skeptical as to whether this measure will provide much needed relief.

"The peak of the dry season will still hit the Amazon in 60 days when that moratorium is lifted," says Barlow. Because there is no environmental agency on site to enforce it, Bolsonaro decision may not be effective, he adds.

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"I am alarmed and worried," says Barlow The edge. "I am frustrated because I know that actions can be taken to improve the lives of local Amazon & # 39; s and protect the remaining rainforest. It has been done before. Between 2005 and 2012, deforestation and forest fires in Brazil decreased considerably. The country also expanded its protected areas and promoted nationwide campaigns to educate people about the prevention of accidental fires.

To date, approximately 80 percent of the Brazilian Amazon remains standing. The areas that have been set on fire in recent months will change, but the most radical ones can still be avoided. As soon as a piece of forest burns, Barlow explains, it is more likely that it will go up in flames again with renewed vigor, which is why preventing the spread of fires should be a top priority in the future.

Fortunately, the past shows that this is possible with increased education and protection. These measures do not have to be "high-tech or extremely difficult", says Barlow. "They just want will."