The arrival of spring marks the start of forestry officials’ yearly battle against the destructive emerald ash borer, an invasive species of beetle that could eventually claim all ash trees.
In the years since the beetle was found in Illinois, the city has spent considerable resources treating trees for the infestation — while the county forest preserves and the Chicago Botanic Garden have focused more on tree removal.
The city Department of Streets and Sanitation completed the inoculation of all viable parkway ash trees in 2014, according to department spokeswoman Molly Poppe. After a break to let the treatment work, the process will begin again in 2016.
The department will focus on planting this year to replace some of the 10,000 parkway trees removed each year, Poppe said. Resources dedicated to fighting the beetle will be used to plant 7,800 trees this year.
The city allotted $2 million to treat trees in 2013 and an additional $1.6 million in 2014. The treatments were meant to be a cost saver at $46 per tree, compared with $1,000 to cut down the tree, a Streets and Sanitation spokeswoman said in 2013.
The treatment, called TREE-age, works when it is regularly applied, said Tom Tiddens, certified arborist and supervisor of plant health care at the Chicago Botanic Garden.
“They’ll need to keep doing that,” Tiddens said. “We’re really thinking this insect, sad to say, is somewhat unstoppable.”
Tiddens treated 87 trees at the garden in 2013, mostly as a way to buy time to budget for the cost of removing them. He said the garden removed 10 trees last year and will cut down 10 to 12 in the next month.
There is no way to eradicate the beetle yet, so trees that don’t get regular treatment will inevitably die, Tiddens said.
The Cook County Forest Preserve District will not inoculate trees this year, spokeswoman Lambrini Lukidis said.
The beetle’s persistence has led to the removal of 50,000 trees in Cook County since 2011, when large-scale removal of infested trees began, Lukidis said.
The long line of trees marked with an orange spray paint ‘X’ along the Edens Expressway in the northern suburbs are just some of those slated to be removed in the next two weeks because of the beetle, Lukidis said.
The Illinois Department of Agriculture said evidence of the emerald ash borer has been found in 61 of 102 counties in Illinois, but Tiddens said all counties should prepare for its arrival.
“It’s coming, and get a plan in place,” he said.
