Street trees can be especially vulnerable to pests, disease and lack of water. But it turns out a hidden culprit could also be killing trees—gas leaks.
Here’s something most people who work for gas companies know: When you want to sniff out a leak, check for dead or dying vegetation. Evidence for this dates back to the mid-1800s when naturalists documented the connection between street gas lamps and dying trees, according to Nathan Phillips, a tree physiologist and professor at Boston University.
“The causal mechanisms are most likely, primarily, oxygen deprivation,” says Phillips. “Roots need oxygen to grow and maintain themselves, and natural gas has no oxygen.”
But tree lovers take comfort. There is at least one guy who has made it his mission to save the trees from gas leaks.
“I call him the urban naturalist because he understands the visible indicators above ground of what’s happenening below ground,” says Phillips.
His name is Bob Ackley, and he drove all the way down from Boston to take me on a tour of my own neighborhood.
“This is the first time I’ve been to Philadelphia and I’ve never had a cheesesteak, so what the heck!” said Ackley, when I met him in the historical section of Philadelphia, across from the Constitution Center.