Remove soil from Ginkgo tree roots

At the Arnold Arboretum of Harvard University (the oldest public arboretum in North America), a tool called the Supersonic Air Knife helps to safely and efficiently aerate compacted soil, expose and correct tree root problems, and transplant large trees bare-rooted.
In this video, Arboretum Director Ned Friedman lends a hand with the tool to blow away the soil from a Ginkgo biloba tree, wild collected in China by Senior Research Scientist Peter Del Tredici. This tree was moved from Peters Hill to a new location in the landscape of the Weld Hill Research Building.

More info here.