Stereo photogrammetry is a process used to determine the strain on a certain structure, which is why it was used to investigate the causes of the Space Shuttle Columbia disaster. But NASA engineers–including one who worked on that investigation–are looking into using it to determine how and why trees fall.
If you can gather and analyze data about how trees stress and break in a hurricane or snowstorm, you might be able to determine the best ways to stop that from happening. NASA Glenn engineer Matt Melis joined forces with Cleveland arborist Mark Hoenigman, and used stereo photogrammetry to examine the trees. In a statement, Melis explained it like this:
“Stereo photogrammetry is the science of analyzing sets of stereo images with computer software to accurately calculate full-field 3-D deformation and strains in the structures we test,” explains Melis. “NASA Glenn is the biggest user of this technology in the agency. We use it for measuring structural response on a great many things we test in our day-to-day work. The technique is used on anything from full component testing down to a fundamental materials sample test.”
By painting a pattern of black and white dots on the trees, the software could pick up on the minute ways a tree breaks apart as it fails when pulled by a winch. Through more tests at the Morton Arboretum near Chicago, the researchers were able to determine that knots in trunks were structural weak points in trees, and they also plotted how the ground was deformed when a tree was knocked over.
NASA says a consulting firm has approached the researchers since then, looking to see if they’ll examine branch structures to find ways of fighting against extreme weather events like Hurricane Sandy.