It was just over a year ago that an ecologist and ISA-Certified Arborist, Lisa Montana, contacted me from AECOM, the global architectural/engineering giant. She works in New York City, and is involved on projects that require utility trenching under sidewalks and around the roots of adjacent street trees. When her project sites have contaminated soils, excavation must take place with shovels and bars, the old approach to bare-rooting plants. On sites with clean soils, the workers use air tools, which let them remove soil and preserve important tree roots.
Lisa kindly sent me some photos of air-tool trenching projects she has overseen, and with my apologies to her for the long delay, I’m posting them here. Take a look, and note how persistent and vigorous those critical roots are even underneath concrete pavement.
This one is a 26″ dbh Honey Locust.
This astonishing root mass belongs to a 28″ dbh Oak.
These roots come from an enthusiastic 29″ dbh Norway Maple that needs the rooting area in the lawn beyond the sidewalk.
This final photo shows a 32″ dbh London Plane whose roots are seeking moisture in the bed beyond the fence.
It appears as if each of these trees is reaching underground toward open ground, where adequate moisture and air can be found to sustain them. I have been mulling over these photos for some time, and especially since Hurricane Sandy, when so many uprooted New York street trees appeared to have root masses that conformed to the bar-like shape of their planting spaces. I wonder if those root masses had been cut at some point, as is often done for the reconstruction of a sidewalk or for utility work done in a less sensitive way than AECOMM’s methods.
Thanks, Lisa, for sharing these photos, and giving us a peek at what’s going on under some sidewalks.
Location: New York City
Arborist In Charge: Lisa Montana, AECOMM