Remove untreated ash trees before they die and put homes at risk, Sioux Falls urges

Sioux Falls city officials are urging homeowners to schedule the removal of ash trees that have been affected by emerald ash borers, emphasizing that both cost and danger will only increase as time goes on.

Since 2019, more than 17,000 ash trees have been removed from city property, Director of Parks and Recreation Don Kearney said Wednesday morning. But there are an estimated 45,000 ash trees on private property, he added. And the number of those trees that are becoming dangerous is rising.

The most recent forest health survey resulted in 530 orders to remove ash trees in the city, Kearney said — triple the number they had ordered in 2023.

Why are the trees considered dangerous?

What you want to avoid, said John Ball, a forest health specialist with the South Dakota Department of Agriculture, is waiting until you've got a standing dead tree on your property.

When the emerald ash borer was originally identified in the city, there was an option to begin treating ash trees to prevent or ward off infestation, Ball said.

"But for those that haven't treated their trees and have chose not to remove them, now is the time," Ball said. "The decision has been made for you."

More: It's emerald ash borer season, but what do you do if the Sioux Falls storm took your ash tree down?

If an ash tree has no leaves remaining on it, or its leaves have died back on more than a third of the tree, it should be removed as soon as possible, Ball said.

"Ash dies and falls in an unpredictable manner with EAB," he said. "Sometimes, they'll stand for three or four years standing dead, other times they'll fall just from having somebody walk by them."

The wood can become extremely brittle, leading to large branches falling or even the entire tree falling over without warning. Ball said that in a two-year period in Michigan, where emerald ash borer was first identified in the United States, 18 people were killed by trees that had fallen into the street.

How costly can removal be?

But an untreated ash tree with only minor damage to its leaves is less of a safety concern — although Ball said that the sooner the tree is removed, the more affordable it will be, as it is significantly riskier to cut down a standing dead tree.

Ball said the difference between removing a living ash tree and a standing dead one could be as much as tens of thousands of dollars.

Who should be removing the trees?

And because of those risks he mentioned, Ball emphasized that this is work that needs to be done by professionals.

The city's website has information about emerald ash borer, including a list of licensed arborists.

This article originally appeared on Sioux Falls Argus Leader: Remove untreated ash trees before they die and put homes at risk, Sioux Falls urges