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Jan. 6, 2020

Researching link between Amazon deforestation and fires

Recent wildfires in Brazil have sparked global concern about the Amazon Rainforest.

More than 38,000 fires were recorded in the Brazilian Amazon biome during the 2019 early dry season, from June to August, when the international crisis exploded.

Historical data from Brazil’s National Institute for Space Research show similar or higher numbers for these same months were common from 2002 to 2008 and were last registered during the 2010 El Niño drought. Unlike 2010, the 2019 increase cannot be explained solely by the rainfall regime. Rather, it seems that this year's fires are linked to increased deforestation – around 10,000 square kilometers – making it the highest rate since 2008.

Researchers speculate that a possible cause of the increase in fires is land being illegally burned and converted for agricultural use. Though at present a complicated legal and economic story, land conversion is broadly connected to international demands for low-price products like beef and soy.

The number of fires have devastating effects on a local and global scale. MSU researchers Scott Stark and Marielle Smith have been studying the rainforest ecosystem in Brazil, each for about a decade or more.

Aspects of their research have been affected by the fires and they are left with great concern and heavy hearts about the loss of rainforest and likely climate destabilization of South America.

Stark’s research team has been studying areas surrounding Santarém and the small town of Alter do Chão, located in the eastern part of the Brazilian Amazon, collaborating with Susan Aragón of the landscape ecology lab at the Federal University of Western Pará, or UFOPA. The long-term forest monitoring plots were initially set up by the National Institute of Amazonian Research and are now continued by UFOPA.

The Santarém area provides a valuable study site as an isolated piece of savanna contained within the lowland rainforest that covers much of the Amazon basin. Stark and Aragón believe the savanna may have remained in this area after an earlier climate period because of the sandier soils and thousands of years of human fire management, given that Santarem is home to one of the largest Amazonian civilizations: the Tapajos, in contrast to rainforest, which does not naturally burn.

Stark’s team was studying the transitional area between rainforest and savanna when they heard that a major wildfire was headed toward their research sites. Stark was immediately concerned about the area; it didn’t have protection, putting his research plots at risk.

“The closed canopy forest, stunted because of dry air conditions surrounding the local airport, was in bad shape already,” Stark said. His situation was not an anomaly in the region, other forest areas had been negatively impacted by strong wildfires during a major drought in 2015 and 2016.

Stark ultimately received news from Aragón that the majority of their shared study areas had burned. Site visits are needed to properly assess the degree of damage. Even though 2019 was not a bad drought year, when fires are often worse, the extent of damage that this fire caused was greater than any that had impacted the sites in their prior experience.

“It really hurts,” Stark said. “The only upside might be that I’m seriously considering [seeking] money for more detailed monitoring of the early phases of reforestation.”

While the current situation is alarming, it does provide an opportunity to study how forest ecosystems regenerate after fire.

Stark’s research team has growing concerns about the state of the Amazon rainforest. Research suggests that the forest is reaching a critical stage. Because the Amazon actually creates its own climate, once the tipping point is reached, the region may no longer be able to support a rainforest as we know it.

“It can no longer be the same forest, so then it can’t have the same rainfall regime. Then, actually, it’s not just the rainforest that suffers, it’s also the agricultural fields adjacent,” Smith said.

The more distant agricultural “breadbasket” region of southern Brazil receives rainfall from spillover of the Amazon’s wet season and is also threatened by deforestation.

Scientists are not sure what the future forest will look like. Some theorize it may be more like a savanna. It will likely not store as much carbon, be as ecologically diverse or have the same rainfall. For these reasons along with the importance of the climate in the Amazon for the rest of the world, MSU’s research on savannas and changing tropical forests is critical for efforts to find healthy forest solutions to global change problems.

The fires and politically tumultuous situation have left the MSU research team concerned for the future of forests in Brazil, as well as for the future of the Brazilian forest research community. The researchers said that their jobs could become harder. Science in the Amazon is a community effort led by Brazilians, alongside international researchers like the MSU team, and the Brazilian community has been heavily hit by recent funding cuts.

“We’re all hoping that the tide will turn, but it’s practical to know that there will be dark days for a long time,” Stark said. “I’ve been steeling myself as much as I can, given my abilities as a scientist, which means I am limited, but I can do something.”

Fire and land conversion rates have declined since August, apparently connected to national and international pressure for conservation.

The team will continue to work on evidence-based solutions to provide a means to conserve the Amazon forest alongside urban and agricultural regions as a great water and climate resource.