WAfter the emerald ash borer was 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 deal with the imminent threat of the invasive insect.
Albert Lea Parks Department superintendent for the city, Joe Grossman, said in all likelihood there’s a good chance the insect may have already arrived in the city and just not been found.
“I don’t think people know what it’s going to be like,” he said, referring to infested areas in the Twin Cities.
According to the Minnesota Department of Natural Resources, the emerald ash borer has killed millions of ash trees in the eastern half of the United States and southeastern Canada. Native to eastern Russia, northern China, Japan, and Korea, the 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 carries nutrients up and down the trunk. As a result, the trees often show several signs of infestation.
Grossman said Albert Lea has an estimated 12,000 ash trees — 1,100 of them on city property and the rest on private property.
Given the numerous benefits of trees, the plan drawn up with Rainbow Treecare calls for chopping down about 270 of the weakest ash trees on the city’s property, but the remainder undergoes a treatment program with an insecticide injected into the tree over a number of years. He said all ash trees larger than 12 to 15 inches in diameter are treated.
Essentially, the approach is to save the best and eliminate the rest, he said.
He noted that if the trees weren’t treated, in three to five years all the trees would die after an invasion of the emerald ash borer.
When the emerald ash borer was first found in the country, many cities would proceed with cutting down all ash trees automatically, but he said with all the benefits of healthy ash trees, it was worth saving as many as possible. Many cities have tried to treat trees where possible.
He pointed to the benefits the trees provide, including catching rainwater, providing shade and absorbing carbon dioxide. The plan also talks about how trees along roads help extend the life of asphalt by 40 to 60% by reducing daily heating and cooling of the roads.
According to Grossman, city workers began removing smaller ash trees in the community in late fall and have removed about 100 so far. About 170 trees remain to be removed as part of the effort. The trees are replaced with other shade trees such as native bur oak, hackberry, basswood, Kentucky coffee tree, honey locust, and catalpa.
Treatment of the remaining 800 ash trees will begin next spring, with around a third of the trees being treated at a time. He said injections are given into what he describes as the buttress roots of the trees, where the tree flares up below. The city will commission the treatments and has budgeted for the treatment over the next 15 years. More effective treatments will likely be found over time.
“The longer we can keep them alive, the longer we can reap the benefits,” Grossman said.
The plan says the city’s total cost is estimated at about $776,000 by 2042, and the city has received a $100,000 state grant to help manage the Emerald Ash drill.
“I think the plan is well thought out and will save money for the city – and the citizens – in the long term,” he said.
Grossman had been aware of the ash borer for many years, noting how many ash trees were already standing in the city, and said the city mostly stopped planting ash trees in 1996 and has only planted about 20 since then. The city has also cut down many ash trees so be proactive.
Ash trees on private property
Grossman said the city is still considering how to help private tree owners who would pay to treat or remove trees on their properties themselves. With around 10,800 ash trees on private property, the city is planning an awareness campaign to educate the public about the infestation and the city’s efforts.
Grossman estimates that 25 to 30 percent of all trees on private property in Albert Lea are ash trees, a number he says is not uncommon for most Midwestern cities.
“It’s going to be important for people with quality ash trees to treat them,” he said. “They’ll end up saving money — on rainwater harvesting, shading their home… it’s going to be more expensive to remove.”
Among the questions to consider is where the trees that are removed will end up after the removal. The plan states that if 6,500 trees are removed, they will weigh over 6,000 tons and have a volume of about 25,000 cubic meters.
He urged private property owners to consider what types of trees they are planting and to avoid maples, as there is already an abundance of maples in the community.