Shining Laser Light on Earth’s Forests

The International Space Station (ISS) is sporting a new ‘light fixture.’ The Global Ecosystem Dynamics Investigation (GEDI) will beam down laser light on Earth from the orbiting laboratory to reveal more about our environment and how it is changing.

NASA’s GEDI sends laser pulses into tree canopies and precisely measures the light reflected back. The timing and intensity of light that bounces back to GEDI’s telescope will reveal the height and density of trees and vegetation, and the vertical arrangement of the leaves and branches within the overall canopy.

Dr. Ralph Dubayah, GEDI principal investigator at the University of Maryland says, “This instrument will map forests in high resolution and three dimensions, revolutionizing the way researchers monitor them.”

Forested areas are an important part of our planet. Not only do forests provide a habitat for many species and a source of raw materials for human use, such as paper and lumber, they also play a key role in the Earth’s carbon cycle. Deforestation and forest degradation, in addition to other types of forest disturbances such as fires and insect outbreaks lead to increases in atmospheric carbon dioxide. Forest regrowth sucks that carbon back down into trees and soils. Knowing how forests grow and change over time can allow us to better understand the contribution that forests make to Earth’s carbon cycle and help people better manage this important resource. GEDI is the first spaceborne instrument designed specifically to perform sustained mapping of the spatial distribution of the carbon content of forests.

Dubayah notes, "One of the most poorly quantified components of the carbon cycle is the net balance between forest disturbance and regrowth. GEDI will help scientists fill in this missing piece by revealing the vertical structure of the forest -- information we really can’t get with sufficient accuracy any other way.”

GEDI will provide scientists with insights into the amount of carbon stored in forests. When combined with current and historical records of changes captured by Earth-orbiting satellites such as Landsat, this information will enhance the ability of researchers to identify changes happening across our planet.

Researchers also will incorporate GEDI’s observations, along with those of the ECOSTRESS instrument on the station, with data from other current and future Earth-observing sensors. These data will address important questions about relationships between forest structure, function, composition, and changes in carbon content.

Combining all of these data will allow researchers to gain an unprecedented understanding of ecosystem dynamics and the role plants and trees play in Earth's global carbon cycle. These new insights could be used, in turn, to improve models for forecasting future ecosystem changes, atmospheric carbon dioxide concentrations, and climate.

GEDI was launched to the station aboard SpaceX CRS-16 on December 5, 2018.

For more about how NASA uses the power of light to understand our world – and beyond – visit science.nasa.gov.