Exploratory new research has revealed that the Amazon rainforest is not as ‘wild and untouched’ as previously thought and that ancient civilisations actually helped shape the landscape.

The report, published in Science this week suggests that the Native Americans of the Amazon were actively burning, tilling and pruning the land.

Three hundred and ninety billion trees

River around the amazon rainforestIt’s almost unfathomable to picture so many trees, and the two million plus square miles that they fill. What’s also hard to imagine is the 13,000 years of people living in this rampant biosphere, and the 8,000 years of subtle cultivation in that time that has resulted in the Amazon rainforest we know now.

How did they come to the conclusion of cultivation?

It started back in 2013 when a group of scientists led by Hans ter Steege were sampling plots of uninhabited rainforest and found many ‘hyperdominant’ tree species. Of the 16,000 species of tree they found, just 227 accounted for more than 50% of all tree flora, questioning the notion of the ‘world’s most diverse biosphere’.

Cacao pod on treeThe Brazil nut, the Ice Cream Bean tree and the Amazon tree grape are three particular species that are found in abundance here, each which provide an edible ‘fruit’. Cacao, Cashew, Acai palm and Rubber were also found. The Ice Cream Bean tree, known scientifically as the Inga feuillei, produce a sweet white pulp that resembles (you guessed it) ice cream. Their dominance may well be down to cultivation, but the workings of the tree could argue otherwise. Not only can their pulp be consumed, but their seeds can be eaten like a vegetable or roasted as a snack.

Inga species are dependable, they produce in abundance, and they provide sustenance in bad times. A family can produce food without occupying the farmland used for food crops because they can grow on sites neglected by agriculture. They grow rapidly, are tolerant of diverse soils, and are resistant to disease and fire.”

Could the strength of the tree, as well as the others, suggest its dominance is natural? Or is the food producing and resistant nature of the tree a determining factor in why ancient civilisations cultivated it? Information on agriculture from 8,000 years ago is in an unsurprisingly short supply.

What evidence supports their theory?

Location, mainly. Scientists are able to map the natural locations of certain tree types and then highlight when they have been found in areas that are unnatural to their own soil type desires. This would suggest that humans uprooted or planted these tree types in different parts of the forest in order to cultivate them for food, fuel or construction materials.

Scientists also took archaeological sites in the area and laid a grid map over the top of them with data for hyperdominant tree densities. What they found was a direct correlation in the abundance of these species and their closeness to a previous human settlement.

They may, however, be wrong, as were scientists several years ago when they wrongly predicted that some ancient Mayans were cultivators, only to discover that a certain type of bat had in fact been spreading seeds.

The Amazon rainforest, Brazil

Credit: Neil Palmer/CIAT

What could this mean for the future?

With more than half of the world’s remaining rainforest and a large percentage of dangerous terrain that is yet to be explored, the mysteries from within the Amazon rainforest are still beyond our understanding. What some scientists believe this information could do, however, is uncover ancient and as of yet unknown settlements. If people 8,000 years ago were moving plants to certain areas to be grown for food, it is a logical assumption that they lived close to these areas, and as such, there could be mysterious artefacts and ruins to be uncovered.

Cultural artefact or absolute wilderness?

This research will undoubtedly ask more questions than it answers, but the scientists remain confident that there is enough evidence to suggest they are right in their calculations. One fact that will perhaps sway you to the side of cultivation is that large fruit-bearing trees are five times more likely to be dominant in previously inhabited areas of the Amazon rainforest.

Research into this discovery continues, however a potential negative to the story is that more people may now be heading to the rainforest in hope of discovery.