Sample composite that shows a split screen of 2017 and 2018 lidar data over El Yunque National Forest, Puerto Rico. As the animation plays, one can see a distinct difference between the fullness of the 2017 forest canopy versus the much sparser 2018 canopy. This difference is most noticable around rivers and streams where the neighboring forest canopy was stripped away by Hurricane Maria exposing much more of the water banks.
In September 2017, Hurricane Maria's lashing rain and winds also transformed Puerto Rico's lush tropical rainforest landscape. Research scientist Doug Morton of Goddard was part of the team of NASA researchers who had surveyed Puerto Rico's forests six months before the storm. The team used Goddard’s Lidar, Hyperspectral, and Thermal (G-LiHT) Airborne Imager, a system designed to study the structure and species composition of forests. Shooting 600,000 laser pulses per second, G-LiHT produces a 3D view of the forest structure in high resolution, showing individual trees in high detail from the ground to treetop. In April 2018 (post-Maria) the team went back and surveyed the same tracks as in 2017 (before Maria).
The extensive damage to Puerto Rico's forests had far-reaching effects, Morton said. Fallen trees that no longer stabilize soil on slopes with their roots as well as downed branches can contribute to landslides and debris flows, increased erosion, and poor water quality in streams and rivers where sediments build up.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 126.96.36.199.0