Community

Dog Pee Kills Trees (Really)

By Karoline Xiong
Spectrum staff

So, you think dog urine is top-grade tree fertilizer? Huh?

Think again. Dog pee’s a killer.

Dog urine taints soil and, thereby, the stuff that grows from the soil in a couple a ways, said Sam Bishop, 37, education director and arborist for Trees New York.

“It’s either nitrates in the dog’s urine or the salts in the dog’s urine,” continued Bishop, getting down to the science of the matter. “What happens is the salts, depending on what type of salts they are, can be directly toxic to the tree roots. Or, the salt attracts moisture. So, if there’s a lot of salt in the soil, the moisture in the soil is going to be so strongly attracted to the salt that the tree can’t get the water out of the soil.”

Maybe your next-door neighbor knows this? And that information prompted him or her to join a considerable army of New Yorkers who put up those tree guards—rot iron ones, flimsy ones, ones made of plastic and wood. They want your dog to keep off.

“Any kind of vertical surface, dogs will mark … And it serves as a means of communication,” Bishop said. “And from the urine they can find out what other dogs are in the neighborhood.”

Dogs will whizz almost anywhere, he added.

Which is fine–unless you’re a plant or a tree being whizzed upon.

“When the conversation gets started about street trees, people tend to look through the trees, not at them,” said Kim Johnson, 45, founder of Curb Allure, which also is working with tree-lovers in Jersey City, N.J., New Haven, Conn., and other cities.

It’s spreading the message that there should be a tree guard everywhere a tree—and its accompanying groundcover, flowers, et cetera—happens to be in the city.

Johnson’s save-a-tree-from dog pee campaign started six years ago, prompted, initially, by her dislike of what then was her decrepit tree guard in front of her apartment building. “We wanted to renovate not only the inside, but also the outside,” Johnson said.

She planted her first tree-guard then and kept that pattern going.

With 88 percent of all city blocks surveyed, thus far, the New York City Department of Parks and Recreation’s TreesCount! 2015 program has counted 598,884 trees, said Charles Cochran, 28, street tree census coordinator. TreesCount launched in May 2015.

But, here’s the problem, he added: roughly 86 percent of those trees do not have guards, which, in addition to pet pee, also are a barrier against bad weather and human destruction. You know, like, a guy or gal whose car jumps the curb.

The New York Tree Trust, an arm of the parks department that accepts private donations, installs tree guards.

For individuals who want to install them, the process is fairly simple. First, get the city’s required “tree work permit.” “This is to make sure that the tree guard protects pedestrians as well as trees,” Johnson said. Then, buy the guards from any among several outlets selling them.

Note: Some people will disregard a guard altogether.

Believe it or not, some dog owners even purposely pick up their pets and plop them down on ground within the borders of tree guards, Bishop said.

And that’s just teaching bad behavior, Johnson said. For Fido, “it’s just a training issue,” Johnson said.

So, train your dog the right way.

“Trees are a way of fighting a number of simultaneous, urban problems and challenges,” Bishop said. “They remove some pollutants from the air; they help filter and trap them; they absorb and store carbon dioxide … trees shape a city.”

Dog pee, despite what some dog owners and dog walkers believe, does not help trees grow, Bishop and others said.