Dr Ed Gilman of the University of Florida hit the switch on a 900hp wind machine to blast badly looked after trees and ones that had been well pruned and managed.
"Video footage shows unpruned trees bending virtually to snapping point," he said. "Trees that had been strategically pruned show far less movement."
Lack of understanding that trees required maintenance was one of the sector's biggest problems, he said. "There's a science to tree care."
Gilman will address Barcham Trees' conference next June. For details, email firstname.lastname@example.org.