Beam me down: NASA’s GEDI laser to 3D-map Earth’s forests

The US space agency will attempt to map the earth’s forests in 3D, turning its “Lidar” laser device earthwards to precisely measure the depth and shape of terrain from above. The project, called GEDI, will be completed in 2018.

NASA hopes that using the laser instrument to construct precise forest measurements from the canopies down will allow them to draw data and conclusions about their roles in the carbon cycle.

"One of the most poorly quantified components of the carbon cycle is the net balance between forest disturbance and regrowth," Ralph Dubayah, EDI principal investigator at the University of Maryland, said in a NASA statement.

“GEDI will help scientists fill in this missing piece by revealing the vertical structure of the forest, which is information we really can't get with sufficient accuracy any other way,” he added.

GEDI is an acronym for Global Ecosystem Dynamics Investigation. The device itself will use a specialized laser “Lidar” technology system technology and be produced at Goddard Space Flight Center in Greenbelt, Maryland.

“Lidar has the unique ability to peer into the tree canopy to precisely measure the height and internal structure of the forest at the fine scale required to estimate their carbon content,” said Bryan Blair, deputy principal investigator for GEDI.

Lidars – a portmanteau of ‘light’ and ‘radar’ – have been used to map things like craters, geological formations, and even monitor ice melting. However, they have never previously been used to examine forest density.

Three laser beams will be deployed. Using a complex system of optics, they will be divided into 14 tracks on the ground, spaced approximately 500 meters apart.

University of Maryland vice president and chief research officer Patrick O'Shea explained how the technology would aid with carbon measurements.

“In particular, the GEDI data will provide us with global-scale insights into how much carbon is being stored in the forest biomass,” he said. “This information will be particularly powerful when combined with the historical record of changes captured by the US’s longstanding program of Earth-orbiting satellites.

“GEDI lidar will have a tremendous impact on our ability to monitor forest degradation, adding to the critical data needed to mitigate the effects of climate change,” O’Shea said.