If that happens, it would not only affect the millions of people and animals in the region. It could also mean billions of tonnes of carbon dioxide will be emitted into the atmosphere as trees die and vegetation burns; less rainfall throughout central and southern South America; and altered climate patterns farther afield. Last August, the number of wildfires in the Brazilian Amazon was higher than in any August since a drought in The researchers first modelled how the regional Amazonian climate might be affected using various projections about future climate change, levels of deforestation and increased fires.
Then they simulated how the original rainforest would have evolved under these altered climate conditions. The modelling did not investigate how quickly the forest would die over the 80 years of the simulation. Paulo Brando, a tropical ecologist at the University of California, Irvine, says it might require more deforestation to reach a critical point — but the main thing, he says, is to try to keep well away from it.
He adds that the idea could give the false impression that the Amazon is safe below a certain threshold of deforestation and doomed above it. Scientists agree, however, that more global warming and more deforestation put the rainforest at increased risk. Part of the problem is that a lack of data makes it hard to predict how climate change, deforestation and fires intersect, and how the forest will react.
One big uncertainty is how a warmer climate enriched with CO 2 would affect the Amazon. Rammig and others have for years been hoping to test the effect of elevated CO 2 concentrations in the Amazon , by pumping the gas from towers into metre-wide circular patches of forest and monitoring how this affects the ecosystem.
Researchers have performed similar experiments — called free-air CO 2 enrichment FACE — in other forests, but not in tropical ones. Several FACE trials have found that young forests do seem to grow faster in increased CO 2 , although mature eucalyptus trees did not gain extra biomass, a study in Australia reported 7.
For the moment, they are measuring the effect of high concentrations of CO 2 on individual saplings. Another uncertainty is how to model fires.
Most fires in the Amazon are intentional — set either by farmers to fertilize soil or by ranchers to clear deforested land for cattle. In wet years, the fires spread less easily, but in drier years, more trees die and flames surge higher, says Brando.
The Amazon fires of were visible from space, as shown in this image from the geostationary weather satellite GOES This January, Brando and others published a paper suggesting that a warmer, drier climate could double the area of burnt forest in the southern Brazilian Amazon over the next three decades 8. Their study indicates that, even without deforestation, climate change alone will inevitably cause a surge in the area burnt over the coming years.
Researchers also need to improve their understanding of how hundreds of Amazon tree species react to heat and drought, says Oliver Phillips, a tropical ecologist at the University of Leeds, UK. That requires extensive laboratory and field testing, such as setting up a system that simulates a drought by capturing water droplets before they reach the soil. Studies have collected such data in forested areas of east Amazonia, but not in the hotter, drier southern Amazon, Phillips says.
During his election campaign, he told the Brazilian Academy of Sciences that he thought it possible to boost investment in research from 1. But since his government took office, the scientific research budget, which had already shrunk heavily, has suffered extra cuts.
Last year, Bolsonaro fired the director of the National Institute for Space Research , which is responsible for satellite monitoring in the Amazon. That left Brazilian researchers uneasy about publishing work that could upset the government. Last year, several scientists decided not to appear as authors on a study that discussed the causes of the August wildfires, saying they feared government retaliation. The urgent priority is to halt deforestation.
Another is to promote the growth of new forest in degraded areas. A study that analysed thousands of plots across 45 sites in South America showed that secondary forests that emerged in abandoned agricultural lands can take up huge amounts of carbon, at rates up to 11 times faster than those of old-growth forests 9.
In areas that have been heavily deforested, things are more complicated. A study showed that regrowth between and in an Amazon area that had been deforested several times over the past few decades happened slowly, and that the resulting forests accumulate less carbon and have lower biodiversity than native, primary forests Under the Paris climate agreement, Brazil pledged to restore , km 2 of forest by In the longer term, Nobre thinks that Brazil needs to reforest even more — some , km 2 — in southern and eastern Amazonia, the areas most heavily hit by deforestation.
Adopt a carbon tax to protect tropical forests. Nobre and others have also put forward a plan to commercialize Amazonian products in a sustainable way. This lack of information about Amazonian flora on a basin-wide scale has hindered science and conservation efforts, according to experts. The new findings, published in the journal Science , provide the first estimates of the abundance, frequency and distribution of many thousands of Amazonian trees.
Extrapolating the data, compiled over 10 years, suggests that greater Amazonia harbours around billion individual trees, including Brazil nut, chocolate and acai berry. In total roughly 16, tree species are believed to exist in the Amazon, but half the total number of trees are thought to belong to just species.
Almost none of the most dominant species are widespread throughout the Amazon. Instead, most are abundant in a particular region or forest type, such as swamps or uplands. The Brazil -nut tree Bertholletia excelsa is a common tree species which rises above the canopy, reaching 40m. Yellow flowers grow on it, which eventually turn into large fruits, containing between 1 and 2 dozen seeds. Nuts are contained in large woody rounded pods that break open when they fall on the forest floor.
The brazil-nut tree is found on floodplains and terra firma, where it tends to be widely spaced. It is noted for the absence of buttresses and propping roots, which are replaced by surface and underground roots.
The nuts are harvested throughout the Amazon region, and are reportedly tasty, but high in fat content. Our work is only possible with your support. Donate now. Archive Content Please note: This page has been archived and its content may no longer be up-to-date.
Toggle navigation. Language English. The giant kapok tree, the creeping aroids, and other resident architects of the Amazon rainforest. Many species, few specimens Tropical rainforests set records in biodiversity: anywhere between 40 to species of tree can be found in a 1-hectare plot of land. There, at least 1, species of higher plants have been discovered 2. The Amazon is home to as many as 80, plant species from which more than 40, species play a critical role in regulating the global climate and sustaining the local water cycle.
While there may be many species in tropical rainforests, these often exist in low numbers over large areas. Amazon plants and trees play critical roles in regulating the global climate and sustaining the local water cycle. The forests they form are home to the huge variety of animals found in the Amazon.
But their greatest riches yet may be the compounds they produce, some of which are used for medicine and agriculture.
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