Cambridge looks to prevent Emerald Ash Borer invasion

Ash trees like these in front of Cambridge City Hall would be among the first in the city to be vaccinated to prevent the spread of the Emerald Ash Borer.

The March 1 Cambridge City Council meeting featured the words “quarantine” and “injection,” and phrase “stopping the spread” repeatedly uttered by city staff, but for once, they weren’t talking about COVID. Instead, they were in reference to the city’s planned attempts to prevent the Emerald Ash Borer (EAB) from decimating the city’s landscape.

 “It is a very serious, invasive tree pest that attacks and kills ash trees and is spread through short-distance flight,” said Will Pennings, who gave a brief overview of the insect. He went on to explain it’s actually the larva, which tunnels under the bark of ash trees, that causes the tree to die.

Pennings explained that currently, there hasn’t been any Emerald Ash Borers spotted in Isanti County, however it is encroaching on the county’s southern border, with the insect discovered in the St. Francis area.

“They’re having a gigantic battle with it in the Twin Cities metropolitan area,” Pennings said. “On a larger scale, they’re also battling this problem in the Duluth-Superior area, and there’s a big infestation up there.”

Because of the rapid spread of EAB, counties where it is discovered are being put under quarantine conditions by the Minnesota Department of Agriculture, meaning no ash logs, lumber, tree waste, chips, or mulch, along with any hardwood firewood is allowed to be transported outside the quarantined area without an MDA certificate.

“Isanti County is currently not under quarantine,” Pennings said, “however Anoka and Chisago Counties currently are. I do expect Isanti County and possibly the state of Minnesota to be put in this EAB quarantine shortly. There’s talk at the Department of Agriculture about making it a state-wide quarantine.”

Options to combat EAB

Pennings said there are a few things that can be done currently to help and try to prevent the spread of EAB. Among those is to wait and remove and replace infected trees, treat ash trees by injection, do an inventory of all city and private ash trees, plus a public information campaign.

He said public works is currently doing an inventory of all of the public trees in the city to get an idea of how expensive it might be to inject trees with a chemical called Mectinite, which he said has been shown to be 95% effective. He said the city would also do a sort of triage of the trees to determine which ones are worth trying to save versus ones that are already in rough shape for other reasons.

As an example, Pennings said there are 20 ash trees on city land leading up to City Hall. To inject them every three years would cost the city between $1,300 to $1,500. By comparison, removing those 20 trees would cost $5,500 and replacing them would cost between $7,500 to $10,000.

According to Public Works Director Todd Schwab, an initial inventory shows approximately 110 ash trees on city-owned land (which includes land such as the boulevards between streets and sidewalks in front of private residences). Schwab estimates the average cost of the injections, which is based on the diameter of the tree four feet off the ground, would be $75 per tree. This would bring the total approximate cost to be around $9,000 every three years. He said the money from the project could come from the city’s annual “deceased tree fund,” which is a line-item in the budget totaling $15,000 that is used to take down and/or replace city-owned trees.

Schwab said if the council wished to go forward with this project, he would bring back a formal proposal and bid from the Ash Preservation Company, which is a company located in Isanti that specializes in treating ash trees. He said there are other companies out there, but due to the close locality of this company, plus the fact other Twin Cities-based companies already are extremely busy, Ash Preservation Company is by far the most economical choice.

PUD amendment declined

In other action, the council gave a “thumbs down” for a request to amend a current Planned Unit Development at Heritage Greens. According to Assistant City Administrator Evan Vogel, the development company was proposing the city let them out of their current PUD for the southwest corner of Heritage Greens, which called for several single family homes to be built in that area. The PUD also mandated the development include a street running along the houses. In exchange, the developer wants to construct an apartment complex running parallel to 18th Avenue SW and donate the rest of the “L” shaped land back to the city.

City Administrator Lynda Woulfe noted if that land was donated to the city, it would then be the city’s responsibility to construct that street, at a cost of roughly $500,000, since the street is vital to the infrastructure of the area.

The general consensus from the council is that they are not interested in agreeing to this proposal, however they stopped short of making a motion to formally reject it, which does leave it open for future proposals or counter-proposals. In doing so, however, the council made it clear that the city paying for the street construction would be a deal-breaker.

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