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With the emerald ash borer confirmed as close as Alden to the west and Austin to the east, the city of Albert Lea has developed a management plan for how to move forward with the imminent threat of the invasive insect.

Joe Grossman, Albert Lea Parks Department superintendent for the city, said in all likelihood, there’s a good chance the insect has already arrived in the city and just has not been found. 

“I don’t think people realize what it’s going to be like,” he said, referencing infested areas in the Twin Cities. 

According to the Minnesota Department of Natural Resources, the emerald ash borer has killed millions of ash trees throughout the eastern half of the U.S. and southeastern Canada. Native to eastern Russia, northern China, Japan, and Korea, emerald ash borer infests and kills both weak and healthy ash trees by tunneling under the bark and feeding on the part of the tree that moves nutrients up and down the trunk. Often, the trees show several signs of infestation because of this. 

Grossman said Albert Lea has an estimated 12,000 ash trees — 1,100 of which are on city property and the remainder that are on private property. 

With the benefits of trees numerous, the plan, created with Rainbow Treecare, calls for taking down about 270 of the weakest ash trees on city property but the rest going through a treatment program with an insecticide injected into the tree over a series of years. He said all ash trees bigger than 12 to 15 inches in diameter will be treated. 

Essentially, the approach is to save the best and take down the rest, he said. 

He noted unless the trees are treated, in three to five years all of the trees would die after an emerald ash borer invasion. 

When emerald ash borer was first found in the country, many cities would move forward with automatically cutting down all ash trees, but he said with all of the benefits of healthy ash trees, as many as possible are worth saving. Many cities have moved forward with trying to treat trees when possible.

He referenced benefits the trees provide, including intercepting storm water, providing shade and absorbing carbon dioxide. The plan also talks about how trees along streets help extend the life of asphalt by 40 to 60% by reducing daily heating and cooling of the roads. 

Grossman said city staff started in the late fall removing smaller ash trees in the community and thus far have removed about 100. About 170 trees remain to be removed as part of the effort. The trees will be replaced with other shade trees, such as native bur oak, hackberry, linden, Kentucky coffeetree, honey locust and catalpa. 

Treatment of the 800 ash trees that remain will begin next spring, with about a third of the trees treated at a time. He said injections are given in what he described as the buttress roots of the trees, where the tree flares out at the bottom. The city will contract out for the treatments and has budgeted for treatment over the next 15 years. More effective treatments will likely be found as time goes on. 

“The longer we can keep them alive, the longer we can get the benefits,” Grossman said. 

The plan states total city costs are estimated at about $776,000 through 2042, and the city has received a $100,000 state grant to help with emerald ash borer management. 

“I think the plan is well thought out and in the long-run is going to save the city money — and the citizens money,” he said. 

Aware of the ash borer for many years and noticing how many ash trees were already in the city, Grossman said the city mostly stopped planting ash trees in 1996 and since then has only planted about 20. The city has also taken down many ash trees to be proactive.

Ash trees on private property

 Grossman said the city is still determining how it can help private tree owners, who will be paying for their own treatment or removal of trees on their properties. With about 10,800 ash trees on private property, the city plans an educational campaign to inform the public about the infestation and the city’s efforts.

Grossman estimated 25 to 30% of all the trees on private property in Albert Lea are ash trees, a number he said is not uncommon for most Midwestern cities.

“It’s going to be important for people with quality ash trees to treat them,” he said. “It’s going to end up saving them money— for intercepting storm water, shading their house … to remove them is going to be more expensive.”

Some of the issues that have to be considered include where the trees that are removed will go once they are taken out. The plan states if 6,500 trees are removed, those will weigh over 6,000 tons and have a volume of about 25,000 cubic yards.

He asked private property owners to consider what types of trees they plant and to avoid maple trees, as there is already an abundance of maple in the community.