Protecting, removing trees

What to do now for your ash trees

Editor’s note: This is the second story in a two-part series about the emerald ash borer coming to South Dakota.

BROOKINGS – The emerald ash borer may be coming, but the City of Brookings will not be caught off guard. Crews from the Parks, Recreation & Forestry Department have been preparing, said Forestry Superintendent Al Kruse.

They’ve been working with experts like John Ball, a professor at South Dakota State University, an Extension forestry specialist and a forest health specialist with the South Dakota Department of Agriculture, and watching what other cities battling the pest have been doing, and that’s to Brookings’ benefit.

“We’ve learned from other cities experimenting with it,” Kruse said. “Now, they know how to handle it a little better. That’s kind of the advantage of it getting here a little later. We come up with different ways of doing things; the longer we do stuff, the more efficient we get.”

The way they are fighting the invasive beetle – and will continue to fight it – is the same way homeowners can fight it.


“The last five years – we knew it was in Wisconsin and Michigan – we’ve been weeding out a few of (the ash trees) and replanting,” Kruse said.

His crews have been cutting down “hazard ash” and other ash trees that were undesirable, damaged by storms, or reaching the end of their lives anyway. 

The city has been replanting with oak, linden, locust, ginkgo, flowering crab, hawthorn, Kentucky coffeetree, and even some walnuts.

Ball has already cut down the ash tree on his property because he wanted to extend a patio. Cutting down an ash tree now lets you dispose of the wood since there are no restrictions in Brookings County and you have time to plant another species of tree and let it grow for a while. Ball recommends picking a different tree than your neighbors, otherwise we’ll be in the same situation in a few years.

It goes back to when Dutch elm disease swept through the country in the 1960s and ’70s. It was devastating because America had so many elm trees and Dutch elm disease, a fungi that was spread by elm bark beetles, killed most of the elms, according to University of Minnesota Extension.

“We made the mistake of planting so many elms years ago. Then we made the mistake – when we started losing elms – of planting ash,” Kruse said. “We’ve got some streets in town where it’s solid ash for blocks. It really looks cool to have a lot of the same trees, either lined up in the boulevard, or in your yard, but when something like this comes around, then you would lose them all.”

Ball preaches diversity when you replant.

“Not an ash tree and not a maple tree, please,” he insists. “We have far too many maples. My concern is 30 years from now, someone will be sitting at this table, talking to a reporter and we’ll all be saying, ‘Gosh, why did we plant all those maples after the ash died? Now we’ve got some maple borer coming in.’”

If you need help in picking out trees, Ball has written a book “Trees for South Dakota,” and Kruse also recommends checking online to see what trees do well in Zone 4 or visiting a local nursery for advice. 


There are treatments to kill the beetle and save the ash trees, but Ball and Kruse do not recommend starting them yet.

“Treatments are only advised when the insect’s been confirmed within 15 miles of your tree,” Ball said.

The chemicals work as a preventative and treatment, so they can be used when the beetle is found in the area and after it’s found in the tree itself, Ball said.

“I wouldn’t do any injection now because you’re just gonna be throwing your money away,” Kruse said.

Even if you find the borer in your tree, treatments are effective and the tree can recover.

Kruse has been looking into treatments, and he’s found there’s quite a variety.

The chemicals used don’t vary much, but there are different tools and methods of injection; some take longer than others and some depend on the size of the tree.

“We looked at four different types of injection systems, and we’re trying to decide what would be the most efficient for us because, obviously, we don’t want to spend a lot of time on each tree,” Kruse said.

The chemicals generally protect the tree for two years, then the tree will have to be reinjected.

“But it does work good. You do treat these trees, it’s pretty much a guarantee that you’ll save it,” Kruse said.

There’s a catch: you would have to keep treating the tree indefinitely. 

“Basically forever,” Kruse said. “As long as there’s an emerald ash borer around, you’ll be doing it for as long as your heart desires or you want to keep the tree.”

When you stop treating the tree – for instance if you move and the new owner does not treat the trees – “all of a sudden, they lost all their trees,” Kruse said.


Another consideration in whether to take down your ash trees or save them is cost.

Cutting down a tree isn’t the cheap way out, Kruse said.

A tree that is 10 to 12 inches in diameter and 30 feet tall and isn’t surrounded by obstacles can cost $150 to $200, he said. A tree that’s 24 to 36 inches in diameter – “a pretty decent sized tree” and is right next to your house can cost more.

“(If) a lot of it’s got to be roped down and rigged down, then it can cost you $1,000 to $2,000,” Kruse said. “But if that same type of tree was in the middle of a yard where a person could just drop it, that price drops substantially; might only cost you $1,000 to just lay it on the yard.”

Cutting down the tree is a one-time cost, but treating a tree isn’t.

Kruse said treatments can cost between $200 to $250 for a moderate-sized tree.

“You get into the bigger diameters, it’s gonna cost you a little bit more because you have to put more chemical in it and have more injection points,” Kruse said.

Multiply that price by the number of trees you want to save, they warned. And remember all the trees will have to be treated every two years.

Ball suggested people start saving now. 

“I tell everybody in Sioux Falls, get at least two quotes. And it doesn’t always mean go with the lowest. Service is important, as well,” he said.

Don’t forget

What worries Ball is people will forget that the invasion is coming.

“We’re seeing it already … the initial flurry of ‘Oh my goodness, this is horrible’ … Next year, everybody will kind of forget about it (because) we won’t have a lot of dying trees yet,” Ball said. “Once they’re standing dead, they become very brittle very quickly and just collapse.

“So imagine Brookings with standing dead trees that are falling in every direction. (Imagine) about a fourth of our trees and that gives you an idea of what awaits us,” he added.

Cities can take care of their trees, but not all ash trees are on public property.

“Most trees are owned by individuals, not by the city. So really, how fast this insect spreads … is really dependent on how many people treat their ash trees,” Ball said. “What we don’t want is to experience street after street of standing dead trees that are collapsing onto the roadway.”

He’s hoping it’s several years before the borer hits.

“The longer it goes, the better the treatments are. Technology improves every year; better delivery systems, better chemicals; prices continue to drop. It’s a good thing to be able to wait,” Ball said.

Contact Jodelle Greiner at [email protected].

Courtesy photo: Ash trees line plenty of Brookings boulevards, including the ones shown above, and are also plentiful in city parks and on private property. Property owners have to decide within the next few years whether they want to remove the trees and plant a new variety or try to save the ash trees with a preventative treatment.


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