A research team using cutting edge LIDAR technology is mapping the Brazilian Amazon to create a detailed biomass map in order to track the impacts of land use change on forest carbon emissions — data collection required under the Paris Climate Agreement and paid for by the Amazon Fund.

While conducting their LIDAR survey by aircraft, the study team detected several groves of immense trees on the border between Pará and Amapá states. One individual, a red angelim (Dinizia excelsa Ducke) was recorded as being 88.5 meters (just over 290 feet) tall.

A team of 30 researchers, guided by riverine community guides, made the arduous journey to the giant tree groves. They found some of the trees growing atop a hill, which is unusual because big tropical trees generally thrive in low places safe from wind. Further research is needed to learn why they grow there.

The giant trees are more than a source of wonder: each can sequester up to 40 tons of carbon, nearly as much as a hectare (2.4 acres) of typical forest. So, when managing a forest and deciding which trees to cut, it is important to consider tree size. In this particular case, the loss of one giant red angelim’s carbon footprint would be huge.

A combination of scientific curiosity and chance has led a research team that was creating a detailed forest biomass map of the Brazilian Amazon to a unique discovery: a tall tree for the record books.

An individual red angelim (Dinizia excelsa Ducke), discovered in a remote area on the border of Pará and Amapá states, is 88.5 meters (more than 290 feet) tall — the equivalent of a 30 story building. It is the tallest canopy tree ever found in the region, which averages tree heights of 45 meters (147 feet).

The discovery, news of which was first published this August in Frontiers in Ecology and the Environment, occurred while INPE (the National Institute for Space Research) was working on the map — meant to improve Amazon biomass estimation methods, and to enhance carbon emission estimation models due to land use change.

Biomass mapping provides one means for calculating and verifying how much carbon dioxide a country emits due to soil changes brought by land use modification. “As a signatory to climate agreements, Brazil is committed to producing carbon emissions and sequestration reports. A biomass map… [tells] how much carbon is stored in a certain area, and how much is emitted in the event of a fire or deforestation, for instance,” Eric Bastos Gorgens told Mongabay; he is a researcher at the Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM) and member of the INPE biomass project team.

Funded by the Amazon Fund in 2015, the map — to be published in coming months — is the largest Brazilian Amazon data collection project after RADAM, a research program that used remote sensing for natural resource surveys launched in the 1970s.

The biomass survey project relies on cutting edge LiDAR technology, which also allowed for the discovery of the 30-story tall tree. LIDAR utilizes a remote laser sensor which registers objects in three dimensions and is capable of obtaining extremely detailed data, including the structure and height of existing vegetation. The laser scanning sensor was coupled to a single-engine Cessna aircraft, which made 832 flights over the region between 2016 and 2018, covering 375 hectares (926 acres) of forest per collection.

“When we processed the 800-plus samples, we found that the survey had identified seven areas with trees over 80 meters (262 feet) high, six of which were in the Jari River [an Amazon tributary] region. And one of those sites had at least seven giant trees; the tallest one 88.5 meters (290.3 feet) high, was in the Paru State Forest, a conservation unit in Pará,” said Gorgens.

On the way to the giant trees

Once spotted by the LIDAR overflights, the UFVJM professor organized an August expedition to the site to get a closer look at the big trees, and to try to understand the unique processes in their growth development, while also confirming species and actual measurements. The trek was no small undertaking.

Thirty people made the river journey, including researchers from eight universities and research centers (including the Federal University of Alagoas, Embrapa, Brazil; the University of Oxford and University of Cambridge, UK), along with expert tree climbers, first-aid trained firefighters, who were all guided by the riverside inhabitants of the São Francisco do Iratapuru community. A TV crew recorded the trip.

“The Jari region is remote and difficult to reach. We had to go 200 kilometers [124 miles] up the river, where boat wrecks are common because [the stream] is full of strong rapids and rocks,” Gorgens revealed. “We could not have made it without the help of the riverine people, who have experience navigating it.”

Still, the logistics proved arduous. Only wooden boats can withstand the rocks, and several times the team had to unload the four vessels, pull them out of the river and portage around the strongest rapids. Two portages required nearly an entire day each, with the group pulling boats for many hours through the Amazon greenery.

That still didn’t get the team to the grove. From the river they “walked nearly three days into the forest until getting to the first large cluster of giant trees,” said Gorgens. It was then that the researchers confirmed the species as red angelims.

However, the extreme difficulty in reaching the first tall trees prevented the team from getting to the farthest of the three groves, where the 88.5 meter red angelim was located. As a comparison, that tree is only slightly smaller than the Statue of Liberty, which is 93 meters (305 feet) tall including her pedestal.

“We made several attempts to arrive at the tallest tree, but the rugged terrain on the way made the walk dangerous and slow. We [also] still [needed] to climb some [of the big] trees and confirm their measurements, collect botanical material, and make our way back,” the scientist explained. “So we chose to focus on the first site and return within [our trip] deadline.” Gorgens plans a second expedition to reach the tallest angelim.

Understanding the ecosystem

Back at the first site, the researchers counted 15 giant red angelims, the largest being 82 meters (269 feet) tall and 2.5 meters (8.2 feet) in diameter. All grew at the top of a hill, which contrasts with the tallest tree growth patterns typical in tropical rainforests; usually the biggest are found in lowlying areas.

“The biggest challenge for a tall tree is to stand up before gusts of wind and storms. Another factor that limits its growth is [getting] the water supply to the canopy; the higher the tree, the larger hydraulic resistance against the canopy. We want to understand why that region is so special that it houses trees with such unique sizes,” said Gorgens.

Jean Ometto, head of the Earth System Science Center (CCST) of INPE and coordinator of the Amazon biomass map project, stressed the importance of the discovery to Mongabay. “The sanctuary of giant angelims is ecologically remarkable, and it is equally vital in terms of its physiology. We need to understand how that species has grown so much compared to other ones in the region.”

To Gorgens, the discovery is proof of how little we know about the Amazon rainforest and how to preserve it. “Each [of these] giant red angelim, unknown until recently, is capable of holding up to 40 tons of carbon. So the question is: “How are we going to manage those areas where a single tree stores almost as much carbon as a hectare [2.4 acres] of forest? When we think of soil changes, the impact of a giant angelim’s carbon footprint would be huge.” Equally true, the loss of these carbon-storing giants, along with other big Amazon trees, could add significantly to earth’s atmospheric carbon load and to climate change.

Banner image caption: Climbing a giant red angelim. Image by Tiago Capelle.

FEEDBACK: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.