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ENVIRONMENT & CLIMATE_Amazon

Burn damage in the rainforest

This summer, there were more fires in than virtually any on record. Susan Trumbore, Director at the Max Planck Institute for Biogeochemistry in Jena, is looking at the consequences that the immense loss of rainforest has on the local, as well as global . She also examines the likelihood of a forest recovering from a fire. If only it is given the chance.

TEXT TIM SCHRÖDER

he rainforest in Brazil has the region, compared to the same time Fire detectors in space: been burning for decades, period in previous years, with more the fires in the south of over and over again. In than 45,000 fires in total. the are particularly striking in many places, farmers are The fact that most of these fires satellite images from the setting the forest on fire, were not caused by particularly severe Nasa Observatory, whileT elsewhere, clearing is taking place is cause for concern. The past but those in other parts on behalf of beef barons. The goal is to few summers had been even drier. This of are also clearly visible. obtain new farmland to grow soy, increase can be attributed to econom- mainly for fattening animals in Brazil ic interests: most fires broke out on pri- and other countries. Plenty of cleared vately owned land and close to rural land is also home to grazing cattle. settlements. Brazilian experts assume Many farmers also burn their stubble that there has been an increase of fire- fields after the harvest, not taking into based forest clearing in these areas. account that sparks can cause . The most alarming aspect is that there Reports about crop fires are nothing has been a massive increase in the new. However, particularly terrifying number of fires even in public state pictures appeared this summer, as the and conservation areas. fires reached catastrophic proportions in the Amazon - in August. Analyzing satellite images, forest has dramatic consequences. the Brazilian National Institute for Countless and animals are losing Space Research, the INPE, found fires to their habitat, and it is quite likely that

have increased by about two-thirds in hitherto unknown and animal Photo: NASA/EOSDIS

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are being wiped out. The loss of ers to explore how deforestation im- forest is also expected to have an im- pacts regional and global climate, as pact on the climate across large parts of well as the ways in which the forest re- South America, and possibly even on a acts to such climate change. “We do global scale. The Earth system research- not have sufficient data at this point to er Susan Trumbore, Director at the Max accurately illustrate the impact of the Planck Institute for Biogeochemistry in Amazon region in climate models,” Jena, wants to gain a comprehensive Susan Trumbore explains. “We would understanding of the consequences like to contribute to improving climate this overexploitation has on nature. models in this respect.” She examines not only the impact on after forests have slow- THE FOREST STILL ABSORBS THE ly begun to recover years after a fire. FIRES’ She also addresses the question as to what extent the remaining forest has With regard to the local and regional become more vulnerable to further dis- climate, it is of particular importance turbances, such as drought or wind- that enormous amounts of water evap- throw, as farmland advances. She is orate in the forest of the Amazon Basin. collaborating with Brazilian research- This has a cooling effect on the forest

Top 15,000 components, 24,000 screws and bolts, and a total weight of 142 tonnes on a surface area of three by three meters, stabilized with 26 kilometers of steel cables: the Amazon Tall Tower Observatory (ATTO). Left The ATTO is located 150 kilometers to the northeast of the city of , in COLOMBIA the central Amazon region that is still largely untouched. The Tanguro , meanwhile, is in the south of the Amazon Basin, where rainforest meets . EQUADOR ATTO Amazonas Manaus

Amazonas PERU BRAZIL

Tanguro ATTO Porto BOLIVIA Morena Porto ATTO Rio Uatumã

Rio Amazonas

50 km Graphic: designergold and its environment, and half of this further, it could even happen that, on need to understand the role that an in- water is returned to the area as rain. A balance, greenhouse gases are released tact forest plays with regard to the glob- part of the that form move on, in the Amazon region. al climate. This is why, for the past few however, providing rainfall for large Conversely, it is also likely that years, Susan Trumbore and her team parts of South America. global warming will change the forest have been involved in an extraordinary Scientists agree that owing to its and its ability to absorb greenhouse large-scale research project: ATTO, the sheer size, the Amazon region has a sig- gases. Scientists question whether the Amazon Tall Tower Observatory, an en- nificant influence on global climate. rainforest will survive a global rise in semble of three slim steel framework The Amazon Basin that feeds the Ama- temperature by more than two degrees towers, the largest of which, at 325 me- zon covers an area of around sev- Celsius, since there is currently no rain- ters, is taller than the Eiffel Tower. en million square kilometers – about forest anywhere in the world where twenty times the size of Germany. Cur- temperatures are that high. This means THE EFFECTS OF DAMAGE TO THE rently, 80 percent is still covered by for- that the Amazonian forest might disap- POPULATION est. About one-third of the amount of pear due to climate change. “It is im- carbon contained in the Earth’s atmo- possible at this point to predict what a The observatory is located deep in the sphere at the start of the industrial rev- warming of the Earth by two degrees rainforest, about 150 kilometers to the olution is still stored in this area today. Celsius or more would mean,” says Su- northeast of the city of Manaus. The Today, the forest is still able to ab- san Trumbore. “How are habitats, the journey takes several hours, and part of sorb the carbon dioxide that is released chemical and physical processes be- the distance is covered in boats on a riv- through fire clearance in Brazil. How- tween the forest and the atmosphere er. “The area is unique,” says Susan ever, it can no longer filter greenhouse and gas exchange going to change? Trumbore. It is far from any cities or vil- gases from the atmosphere that are gen- And how are these changes going to af- lages. It has the purest air anywhere on erated elsewhere as a result of the use fect our global climate?” the planet. Here, it is possible to take of fossil fuels. If the deforestation that To be able to assess the feedback ef- very accurate measurements of the ex- had initially slowed down after 2003, fect between climate change and the change of substances between the un-

Graphic: designergold but increased again in 2019, accelerates shrinking rainforest, scientists first touched forest and the atmosphere. > Photo: Achim Edtbauer / MPI for Chemistry

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phisticated methods to measure and calculate which amounts of which substances are exchanged between the forest and the air. Other equipment is used to measure wind direction and speed, as well as solar irradiation above the forest. The researchers working with Su- san Trumbore at ATTO not only mon- itor substance and energy exchange between the forest and the atmo- sphere. They also examine the effects that damage has on the tree popula- tion. A few years ago, entire clusters of near the observatory were knocked over by . This created clearings in the otherwise “This is pretty much the last place on dense forest that provide ideal re- Earth where we can examine the origi- search sites, the biggest of which is 28 nal impact of a large intact forest,” ex- hectares in total – about the size of 40 Trumbore. soccer fields. Provided, that is, that there are no fires on the southern edge of the Ama­ RESEARCH AREA IN zon combined with unfavorable wind A BRAZILIAN HOTSPOT conditions. This causes soot particle aerosols to travel northwards, for ex- Susan Trumbore and her team are able ample. As is prone to con- to conduct research on a wide range of densing on such aerosols, causing aspects here, such as the rate at which droplets to form, it is feasible that fires trees decompose and to what extent in the south can have an impact on they release their stored carbon as they formation and rainfall across the do so. Severe may occur more entire Amazon Basin. However, experts frequently due to climate change; are not yet able to tell whether this storms that are strong enough to up- Left Susan Trumbore explores the will lead to more rain or to any chang- root trees by the dozen. The de- interdependencies of the Amazonian rainforest and the climate. es in the rainfall areas. composes and the forest’s is re- The measurement towers were con- duced as time goes by. Top Advancing agriculture: large forest areas have to make room for structed step by step by Brazilian and Susan Trumbore and her team farmland at the edge of the Amazon German research institutions, includ- members are also examining the speed Basin. This has caused a hotter and ing the Max Planck Society with funds at which the affected forests regener- drier local climate, despite the fact from the Federal Ministry of Education ate. They have found that evaporation that the remaining forest still has a cooling effect and provides and Research. They are full of devices and recover within the conditions for rain. for measuring carbon dioxide, methane just a few years, as these functions are and other substances, as well as the taken over by rapidly growing shrubs amount of aerosols contained in the and trees. It takes decades, however,

atmosphere. The researchers use so- for the same amount of biomass that Photo: Paulo Brando

62 MaxPlanckResearch 4 | 19 was contained in the old tree popula- the south of Manaus in the state of There is already evidence that the in- tion to reform. It takes even longer for Mato Grosso, the driest part of the tense deforestation is causing the cli- the forest to become nearly as biodi- Ama­zon Basin. The transition zone be- mate to become even hotter and drier verse as it was before. tween dense Amazonian forests and in this region, which already experi- Susan Trumbore compares the re- is typical of the region. The ences a five-month dry season. sults from the ATTO area with mea- land on the Tanguro Ranch is inten- In addition, scientists are examin- surements taken in a second region in sively farmed. In recent years, there ing the extent to which the remaining Brazil, where she has been conducting have been more clearances in this area forest on the edge of the savanna is af- research for a number of years now. than anywhere else. fected – and whether it stands a chance This research site, the Tanguro Ranch, Researchers analyze how the local of recovery on land that has been is located in a Brazilian hotspot, where climate is changed by this loss of trees, cleared. In order to answer these ques- the forest meets cleared savannas and but they also take a look at global cli- tions, a team of experts from Brazil,

Photo: Paulo Brando farmland, about 2,500 kilometers to mate effects caused by deforestation. Germany and the Hole Research Photo: Paulo Brando

4 | 19 MaxPlanckResearch 63 Underestimated threats: fires on forest floors are invisible to satellites. Based on smoke measurements, ATTO can register these fires, too (left). Grasses can spread on cleared land and invade adjacent forests (right). They can grow even taller than Susan Trumbore, and they take light away from seedlings. They there- fore hinder the forest’s regenera- tion and they also make the forest more vulnerable to fire.

Center in the U.S. launched an unusu- more quickly. This effect continues to Ten years after a fire, the forest has not al project in the early 2000s: fire exper- this day, eight years after the last fire. fully recovered: a young, bushy forest iments carried out in three forested A noticeable number of trees are still that grows after a fire does not provide 50-hectare areas in the transition zone dying from the consequences of the the conditions for the same to the savanna. fires. Furthermore, the now more open as the original one. Even worse: in Between 2004 and 2010, the re- forests have become invaded by vari- some areas, the forest may disappear searchers set one plot on fire every year, ous grasses. These prevent trees from completely after a fire. “We can ob- and another one only once every three growing back, as they take away light serve that fires make forests, and par- years. The third plot remained un- and nutrients from seedlings. ticularly their edges, more vulnerable,” touched. They then allowed the forest says Susan Trumbore and goes on to to recover. In the meantime, they ana- FIRES ARE MAKING FORESTS explain that a main driving question lyzed the climate conditions and sub- MORE VULNERABLE of the research is to find out whether stance flows on the burned plots, and repeated fire will eventually turn the compared these to corresponding data Measurements show that as in the forest into savanna. “We assume that from a nearby soy field, from the edge ATTO region, trees that are growing there are tipping points, beyond which of the forest, and from a measuring sta- back can perform vital ecosystem ser- a forest is no longer able to recover by tion located deeper in the forest. vices after just a few years, especially itself and will disappear,” she explains. The researchers found that the fires compared to a dry soy field. Evapora- The exact tipping point has not been did not overly affect the forest in hu- tion and photosynthesis, and therefore identified to date. mid years. In dry years, however, and the absorption of carbon from the air, This is why Susan Trumbore and these have become increasingly com- had normalized once again by 2017. her team also want to find out which mon in recent years, the fire burned a Evaporation also has a cooling effect in species of trees stand a chance of sur- large number of trees. As soon as the this hot region, and this shows how im- vival in the increasingly dry and hot re- fire had created large gaps, the sur- portant it is to conserve forests, at least gion around the Tanguro Ranch. “It is rounding forest thinned out, as it had in part, in areas used for agriculture. quite possible that species that grow become more vulnerable to wind, and However, significantly less carbon is back quickly will also die again quick-

because the more open forest dried out now stored on these plots. ly,” she says. “We do not know yet Photo: Paulo Brando

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Dilma Rousseff, had promoted im- proved farming methods to exploit the more effectively, and in so doing to increase production and reduce the pressure on the forest. Jair Bolsonaro, however, is promoting an expansion of the areas used as farmland. Susan Trum- bore believes that import nations are partially responsible: “The situation is not going to change unless they urge Brazil to treat the remaining forest with greater care.” It goes without saying that people in industrial countries must pay more which species have what it takes to form to the environmental foundation attention to the origin of resources a new, robust forest under these tough- WWF. However, is the biggest used to make the food that they buy – er climatic conditions.” importer of soy, accounting for 60 per- and promote products and practices Susan Trumbore was also shocked cent of global production. About half that recognize the value of rainforests. by the extent of the fires that afflicted of this is produced in Brazil. After all, finger-pointing is not going this region a few months ago. Howev- The predecessors of president Bol- to save the Brazilian rainforest from er, she points out that the land that is sonaro, Luiz Inácio Lula da Silva and further destruction. cleared every year has somewhat de- creased in recent years. Significantly

bigger forest areas were still disappear- ing every year in the early 2000s. The SUMMARY scientist cannot tell to what degree the l In summer 2019, an extraordinarily large number of fires raged in the Amazonian devastating fires of 2019 are linked to rainforest. Many of these were started deliberately and were boosted by increasingly the policies pursued by the Brazilian dry conditions.

president Jair Bolsonaro. “The long re- l Teams working with the Max Planck researcher Susan Trumbore are examining the cent drought period is likely to have ways in which the rainforest and the climate affect each other, at both the Amazon Tall contributed to this, too.” Tower Observatory (ATTO) in the heart of the rainforest and on the Tanguro Ranch in At any rate, in her view, Brazilians the State of Mato Grosso. are not solely responsible for conserv- l In areas that have been cleared, and where much less water evaporates, it is getting ing the Amazonian rainforest. “People hotter and drier. This also has an impact on rainfall in other areas, as the Amazonian rainforest determines the water balance of the entire region. The CO2 that is released from industrial nations are good at tell- through clearing has an impact on the global climate. ing others how to do it right. At the end l If the forest is allowed to grow back on cleared land, the exchange of carbon dioxide of the day, we citizens of industrial and water between the and the atmosphere can reach almost its original countries have contributed to creating level after just a few years. However, far less carbon is stored in degraded forest, this situation,” she says. Around 80 per- which remains more vulnerable to heat, drought and windthrow. This in turn can lead cent of soy imported to Germany to further die-off and a rapid shift to a new stable state of savanna vegetation.

Photo: Paulo Brando comes from South America, according Photo: Paulo Brando

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