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This new NASA mission will create an unprecedented 3D map of the forests of the world

The secret to stabilizing the earth's climate can rest in the world's forests. Therefore, a team of researchers sends a…

The secret to stabilizing the earth’s climate can rest in the world’s forests. Therefore, a team of researchers sends a high-tech reconnaissance to the International Space Station this week to find out how much carbon is stored in our planet’s trees.

Embedded in the next SpaceX Dragon spacecraft and only armed with a laser altimeter, the Global Ecosystem Dynamics Survey (GEDI) is waiting for deployment. The LIDAR instrument will be launched on December 4, and is designed to map the world’s forests in 3D, thus giving us better estimates of their biomass and how much carbon they store.

The forests of the earth, like the oceans, absorb carbon from the atmosphere. But deforestation and other disturbances can lead to carbon dioxide being released, and we still have a lot to learn about which forests are coal deposits and which are carbon sources at global level. According to Ralph Dubayah, Professor of Geosciences at the University of Maryland and GEDI’s main researcher, it will be difficult to predict future concentrations of carbon dioxide in the atmosphere without that information.

Not only do we need to better understand the carbon balance, we need to know how coal is distributed spatially in the forests. GEDI will contribute to filling in these critical gaps in carbon dioxide accounting.

Instrument Global Ecosystem Dynamics Investigation Lid (GEDI) Mounted on NASA Goddard Photo: NASA

It does it by weighing trees. It sounds like a complicated company, but fortunately, Dubayah and his team have armed GEDI with a powerful laser that can do exactly without chopping any of them. Essentially, a scientific legobit, when GEDI was removed from the dragon’s sluice, it will be installed by robot arm at the exposed plant of the Japanese Experiment Module. GEDI comes from its orbital perch to provide the first high resolution observations of the global forest’s vertical structure on a global scale.

GEDI measures this vertical structure using three lasers that will burn pulses 242 times a second on earth. It will then take time as long as it takes some of the light to return to the instrument. One of the mission’s biggest challenges was simply to have enough laser power and sensitivity to see through dense tropical forest beds.

As the laser pulses travel through the woods, reflections that are reflected back to mark the forest’s 3D structure much like an echocardiogram show a doctor your blood vessels in your heart. “We can see and measure how high the tree is and we can actually see how dense leaves and branches as we descend,” said Bryan Blair, GEDI instrument researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, to Earther. Dubayah added that by the end of its planned two-year mission, GEDI has collected more than 10 billion measurements that will provide the most detailed map of the world’s forests.

Trees resemble people in terms of height and weight. If you were looking at people and making a graph of weight to weight, you see that higher people tend to weigh more than shorter people. It’s the same with trees. So if we know how tall trees are, we can convert their height to biomass numbers and gain their weight. In this way, we will know how much carbon will be released when we destroy them. In addition, the height and vertical structure of the trees can tell about habitat quality and how changes in structures affect habitat quality and biodiversity.

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