Wisconsin and other states are gearing up to battle the emerald ash borer beetle, an invasive species that poses a fatal threat to ash trees.

City workers in Madison have marked 8,500 ash trees with the ominous yellow dot, a spray-painted indicator of which trees will have to be removed, the Wisconsin State Journal reported. Around 12,500 additional trees on street terraces will be chemically treated this month as the city works to save as many as possible.

The non-native beetle, which comes from Asia, was first found in Detroit in 2002 and has since spread to more than a dozen states as well as parts of Canada. It can destroy whole forests and works by eating through the vital parts of a tree's inner bark that hold water and nutrients.

"We're trying to treat and save everything worth saving," Parks Division facilities operations manager Charlie Romines told the State Journal. "We understand the feelings of homeowners. But they're dealing with one or two trees. We're dealing with 20,000 ash trees on the terrace."

The combined cost of treating healthy trees, removing infected ones and replanting for new growth could run the city $19.1 million by 2020. For comparison, that total budget could buy a new library branch, police station and 14 Metro Transit buses for Madison, according to the State Journal report.

The trees will be treated through chemical injection, a process that won't be harmful to animals, birds or other insects that land on the ash trees but don't try to eat them.

Residents in Ankeny, Iowa, are also steeling themselves against the invasive ash borer, which has destroyed more than 50 million trees in the country, according to The Des Moines Register.  

"Instead of the info just being doom-focused, we are really trying to give people options for how they can prepare," Iowa Department of Natural Resources Urban Forestry Specialist Shane Donegan told the Register.

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