Terra-i snapshots #1: A quick tour of some deforestation hotspots… and at least one reason for optimism

8 May, 2013 by (comments)

Tucked away at the back of the one storey building that is CIAT’s Decision and Policy Analysis Research Area, is a door marked E0-30. Inside is a warren of offices, one of which is the Terra-i nerve centre.

Here programmers and GIS experts use images from satellites hundreds of kilometres above Earth to track deforestation in Latin America in near-real time. Sipping coffee from a Star Wars mug, Terra-i team leader and principal developer Louis Reymondin invites me on a virtual tour of the continent’s forests to demonstrate the power of the system.

Terra-i works by using the satellite images of Latin America taken every 16 days, overlaying them onto Google Maps, and analysing any changes in vegetation cover. With the help of some bespoke algorithms courtesy of Reymondin et al, these changes show up as different coloured pixels on the map. Yellow indicates the earliest changes dating back to 2004, warming up through shades of orange and red and finally to magenta, the most recent, in 2012. Each pixel represents an area of land equivalent to about eight football pitches.

You can fly all over Latin America in seconds, zooming in on places of interest, seeking out past and present deforestation hotspots.

“If we go to Pando department, in Bolivia, we can see intense pressure right up against the border with Brazil,” says Reymondin. And off we go, taking a southern trajectory from Colombia, into the western reaches of the Amazon Basin in Brazil, and continuing due south to Pando. When we arrive, clusters of yellow, orange and red pixels tell a story of prolonged forest clearance. “It’s probably driven by livestock production,” he says, zooming in on the Brazil-side of the river border to reveal large, disorderly swaths of cleared land, with a sparse scatter of standing trees. “If the land clearance was for crops we’d expect to see something much more orderly and organised.”

Terra-i Pando1

Slightly east, and crossing into Peru, Terra-i picks up more pressure on the forest, the satellite images revealing striking scarring along a section of the Madre de Dios river, which itself is the colour of pale caramel. “This is typical of gold mining,” says GIS expert and Terra-i team member Alejandro Coca. “Sudden, heavy sedimentation is one of the effects as miners destroy the river banks in search of gold.” A review of existing research revealed that it is indeed a gold mining area, and the Terra-i images clearly show new areas of deforestation further along the river, almost certainly a sign that the activity is spreading. The Terra-i team has plotted rates of deforestation in the area that perfectly match the rise in the international gold price, and the price of mercury – used to recover gold from silt.

Terra-i mining 1

It was while flying around the region from the comfort of his swivel chair that Reymondin recently spotted an unusual pattern of deforestation in Pará State, Brazil – home to some of the highest rates of forest destruction in the Amazon. He’d stumbled upon the Parakaña indigenous area, an oasis of almost perfectly intact forest. Judging by the thick clusters of coloured pixels all around it – and particularly to the south and west – the forest nearby had recently met a rather bitter end. But for some reason deforestation stops abruptly at the border to the Parakaña area.

“You’d expect to see at least a small amount of forest clearance inside,” he says. “But it’s completely intact. We’d love to know how they’ve managed to protect the forest so effectively. That kind of information would be great for us and the rest of the world to know – particularly policymakers developing REDD+ programmes. Hopefully they’re reasons to be positive about the prospects for conserving the forests and the protecting the environmental services they provide.”

Terra-i parakaña 1 with text

Terra-i parakaña 2_with text

Immediately outside the zone he searches for clues as to what’s driving the deforestation. The map reveals more of the disorderly swaths of land with occasional standing trees: more livestock production, he reckons. As we glide slightly west, Reymondin pauses over what looks like a clearing, probably less than a kilometre from the border of the indigenous area. As we zoom in, a saw mill is unmistakable, with lots of large tree trunks stacked up in several distinct piles near a large hangar-like structure with a metal roof.

“Even with the saw mill right on the doorstep, the borders of the indigenous area are being respected – so much so that you can see them clearly, from space. There must be lessons to be learned there.”

At our next destination, it quickly becomes clear that a designated indigenous area on its own is not enough to preserve the forest. As Reymondin flies southwards and zooms in on Brazil’s Mato Grosso State, we arrive at the Xingu indigenous area where immediately Terra-i reveals clusters of red pixels clinging to ribbons of the Xingu River, indicating relatively recent forest clearance.

Whatever the land use changes happening here, there don’t seem to be any signs of gold mining, so it’s highly likely that the logistical value of the river itself is tangled up in the list of causes. Reymondin and Coca say it’s something they see a lot – forest clearance fanning out from transport routes, especially rivers and newly built roads. Roads and rivers allow for easy transport of people and machines coming in, and timber, crops and livestock going out. Parakaña has neither a river, nor a significant road running through it. Perhaps that helps to explain why its forest is still standing.

Terra-i Xingu

It turns out that the latest hotspots in the Xingu area are so new it’s not possible to zoom in closer to try and work out what’s happened. But Reymondin and Coca have their suspicions: moving north to deforestation hotspots nearby, the map reveals highly organised, homogenous patchworks of rectangular fields. They look at each other: “Soybean.” In one of the fields the deforestation is so recent you can even see the scatter of felled trees, lying like tiny matchsticks on the dark soil.

Since Terra-i is open-source and free to use, Reymondin expects that as the system attracts more and more users, anomalies like the Parakaña indigenous area will pop with increasing frequency – little patches of intact forest that seem to buck the broader trend of land clearance. “We need to find a way to explain these,” he says. “At the very least they show that, while there are many reasons to be concerned about the fate of the forests in Latin America, there are also some bright spots that give us reasons to be optimistic.”


Terra-i was developed by CIAT, The Nature Conservancy, King’s College London and the University of Applied Sciences and Arts Western Switzerland.


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Filed Under: Latin America and the Caribbean