Could healthier trees prevented damage caused by Isaias?
by Sara Krevoy
Aug 19, 2020 | 7735 views | 0 0 comments | 489 489 recommendations | email to a friend | print
Decay and hollowing observed in trees that fell in Glendale and Flushing during Tropical Storm Isaias. (Photos: Carsten Glaeser)
Decay and hollowing observed in trees that fell in Glendale and Flushing during Tropical Storm Isaias. (Photos: Carsten Glaeser)
More than 10,000 emergency work orders for downed trees and fallen or hanging limbs were issued by the Parks Department in the aftermath of Tropical Storm Isaias, which tore through the city on August 3.

City data shows 4,990 of those orders were issued in Queens, the most of any borough followed by Brooklyn, which received 2,693 orders. Queens also suffered the greatest amount of power outages, as falling trees ripped power lines, blocked roads and crashed into cars and homes.

And while many of the borough’s elected officials are currently focused on criticizing Con Edison’s response to sweeping power outages, inquiries surrounding the fall of so many city-planted urban trees are few and far between.

The answers to unasked questions about the health and maintenance of street trees, however, could be critical to lessening the blow of citywide damage in the future.

“The storm is really the testing ground,” said Carsten Glaeser, an independent Queens-based arborist who has operated an urban tree consulting firm for more than 25 years. “Many of these trees were in appalling, declining condition with advanced decay well before the storm.”

In the days after the storm, Glaeser, who holds a PhD in plant biology, observed fallen trees in Glendale, Flushing and other neighborhoods, many of them snapped at the base or uprooted completely.

This calls into question the integrity of their root systems, he says, but it is also indicative of preexisting issues with the trees’ health.

“All tree failures have one common experience,” noted Glaeser, “unchecked advanced wood decay and critical weak woodenness, caused by the decay, that had been present for several years.”

He went on to explain that the fungi responsible for this irreversible wood breakdown is “more often than not introduced by tree bark wounding,” which he adds is “commonly caused by unknown and undocumented construction impacts or by inferior pruning practices by novice or unqualified street tree trimmers.”

Each year, the Parks Department plants thousands of street trees, incorporating them into the city’s urban infrastructure. Though they do pose a risk to people and property, these trees provide incomparable benefits to the environment and residents’ quality of life.

Some examples include intercepting stormwater runoff, absorbing air pollutants, releasing oxygen, offering shade, helping to conserve energy and storing carbon dioxide that contributes to climate change.

According to the Parks website, tree planting sites are vetted by forestry staff to ensure they can accommodate healthy growth, and that the new tree does not conflict with any utilities at the location.

Once planted, all street trees fall under at two-year guarantee.

“During this time, the planting contractor is responsible for regular maintenance of the tree, including weed removal, replacing missing soil or mulch and minor pruning,” the page reads. “If a tree dies during the guarantee period it will be replaced in the next planting season.”

After spending more than a decade working in forestry with the Parks Department, Glaeser is not convinced the agency is doing enough to ensure street trees are able to develop a healthy root system, nor to inspect them for decay.

Too much emphasis, he argues further, is put on excessive tree pruning that can be counterproductive.

Since a tree’s physiological growth is usually separate from its structural growth, a street tree could appear to be sound and healthy on the outside despite being structurally weak internally.

The untrained eye would have no idea a particular tree was at risk until it was already too late.

“At the tail end of all this, the decision to remove trees only comes when a storm comes through, when they're falling down or if they are visibly dead,” said Glaeser. “So many of the ones that fell in this last storm you wouldn't even notice an issue until it fell.

“Then you see it’s completely hollow with 30 years of decay in the trunk and you realize that tree should have been taken down, and yet it wasn't,” he continued. “It’s all about preserving the tree. The larger the tree is, the better it is at providing the services we need from it.”

Glaeser says the simplest way a homeowner can test for potential risk posed by a tree in front of their property is to tap its trunk near the base with a rubber mallet to see if it sounds hollow.

Residents can report street trees for investigation by calling 311 or by filling out a service request at

A Parks spokesperson did not respond to questions concerning how often a street tree is assessed for decay and risk of falling during its lifespan, instead offering a statement on the department’s response to damage caused by Isaias.

“Faced with more service requests than we typically receive in more than four months,” the spokesperson wrote in an email Friday, “we expect to resolve the balance of our Tropical Storm Isaias-related tree emergencies today. Trees blocking streets and on houses first and foremost.”

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