Tallest tree in the Amazon found by University of Cambridge researchers
Scientists have discovered a tree in the Amazon that is 30m taller than the previous record holder.
Researchers at the University of Cambridge joined an expedition to confirm the height of the Angelim vermelho (Dinizia excelsa), which proved to be an astonishing 88.5m.
It was one of a group of giant trees found in this remote region of north-eastern Brazil and suggests the Amazon’s importance for storing carbon may be even greater than thought. Just one of these magnificent trees is thought to store as much carbon as a hectare rainforest elsewhere in the Amazon.
Toby Jackson, a plant scientist at the University of Cambridge Conservation Research Institute, joined the epic quest to find the tree, which had been identified using data captured by laser scanning from a plane.
The group set off by boat from Laranjal do Jari in north-eastern Brazil. In 35C heat, they headed for the community of São Francisco do Iratapuru, where villagers provided four boats and 12 people to guide them through the forest.
“It was quite a tough journey,” Toby tells the Cambridge Independent. “We went 220km up the river, which took us about five days. Some days we did really well on the river – we covered 70km one day. But then other days we did less than 10km because there were waterfalls and rapids.”
At times they were waist deep in water,pulling the boats through eight kilometres of rapids and rocks, sometimes using ropes.
At one point, they snapped a propeller on a submerged rock, leaving them without power or steering as they battled upstream through the rapids. Luckily, someone had packed spare propellers – and they used all of them.
“The most interesting wildlife for me was the river otters,” recalls Toby. “They would come around in pairs and got very loud in the evening.”
Sleeping overnight in hammocks with mosquito tents, the team from Brazil, Swansea, Oxford and Cambridge were led by Professor Eric Gorgens, a researcher at the Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM) in Brazil, along with colleague Diego Armando da Silva.
It was Prof Gorgens who had discovered the group of tall trees using the results of the remote sensing method known as LIDAR, which stands for LIght Detection and Ranging. It works by firing a rapid laser pulse at the surface and measuring the amount of time it takes to return.
“When the plane flies over it is recording the spatial information as well as height so you can project your data onto a world map,” explains Toby. “So we had a GPS location from the LIDAR survey. We spent a few days at the site walking into the forest, finding the trees.”
Once they reached their destination, the method of measuring the height of the tree was gloriously simple.
“A guy called Fabiano climbed up and threw a string down with a weight and we measured the length of the string!” says Toby, who is based in the David Attenborough Building.
The group found at least 15 giant trees over 70m tall and some topped 80m. All were the same species, despite the variety in the forest. It is a species common in the Amazon, and its strong, somewhat smelly, wood is often used for timber.
Each Angelim vermelho tree can store as much as 40 tonnes of carbon – the same as 300 to 500 smaller trees, despite occupying the space of only 20.
It had been thought the trees topped out at about 60m, and the researchers do not yet understand why these ones managed to grow so high. They may have taken advantage of a disturbance that had cleared part of the forest – perhaps a storm or human intervention – and then grown into the gap as a pioneer species.
It is thought the trees could be 400 years old and the reason they have survived so long must be partly attributed to their remoteness from urban areas and industry.
Seven of the 850 randomly distributed sections of the Amazon that were laser scanned between 2016 and 2018 by Brazil’s National Institute for Space Research contained these trees. Most were in the area surrounding the Jari river, a northern tributary of the Amazon.
“It’s the biggest survey that has been done, but it is still a small area in comparison to the total area of the Amazon,” Toby points out.
It is possible that an even taller tree is out there in the Amazon.
“This region almost certainly stores more carbon than previously thought because our estimate of the maximum tree height was out. But we don’t know if this is a very local effect, without much global significance, or whether it is an effect that may go on for hundreds of kilometres around the site.
“What is going to tell us this is a new NASA satellite mission, dedicated to looking at the height of trees. It is the first space-borne LIDAR, with the same instruments we had on the bottom of the plane, but attached to the International Space Station. It is up there already and the data is imminent.”
This GEDI (Global Ecosystem Dynamics Investigation) mission will offer high-resolution laser ranging of Earth’s forests and topography. It will help us understand how deforestation has contributed to atmospheric CO2 concentrations, how much carbon forests will absorb in the future and how habitat degradation will affect global biodiversity.
What is already clear is that the protection of the Amazon against the threats posed by logging, burning and agricultural expansion is paramount. Not only does it store huge amounts of carbon, but it is still throwing up incredible surprises.
“We’re in danger of destroying something before we even understand it,” warns Toby.
More by this authorPaul Brackley