Lasers, droughts, and a 3D view: NASA maps the Amazon to examine tree mortality.
For the tall tree canopy of the Amazon rainforest, 3-dimensional maps made by airborne laser technology are giving scientists a new perspective on tree mortality. The high-resolution scans are created from a light detection and ranging, or LiDAR, instrument that sends out 300,000 pulses of light per second that bounce off of leaves and branches and record their height. NASA researchers used these detailed 3D maps of the forest canopy taken in 2013, 2014, and 2016 to find gaps where trees and large branches have fallen and analyze how the forest responds to environmental changes over time. During the non-El Niño period from 2013 to 2014, the branch and tree fall events altered 1.8 percent of the forest canopy in the study area, a small number on the surface but scaled up to the size of the entire Amazon, it's the equivalent of losing canopy trees or branches over 38,000 square miles, or the area of Kentucky. Tree and branch mortality was 65 percent higher during the El Niño drought period from 2014 to 2016, or 65,000 square miles, the size of Wisconsin. Small changes in the Amazon add up. In addition to understanding the immediate effects of dryer years, droughts are also good indicators of how forests will behave in future warmer climates. Watch the video to learn more.