CHICAGO (CBS) — On this Arbor Day, a new study commissioned by the Morton Arboretum showed Chicago area residents are worried about the health of the region’s trees.

“It’s something they should be concerned about, because we’re losing about 13 million ash trees across the region,” said Lydia Scott, director of the Chicago Region Trees Initiative at the Morton Arboretum.

The emerald ash borer has done a lot of damage in the Chicago area. Approximately 13 million trees have been removed due to infestations of the notorious beetle.

“Because ash is a popular tree that’s planted across the region, and because we have so many of them, it’s becoming very apparent to people that there are problems with the trees in the region,” Scott said.

Even though tree lovers can blame the bug, Scott said it’s partly our fault.

“We saw this happen with the elm trees, when we had Dutch elm disease, and we should have learned the lesson then, that diversity is important,” she said.

Scott explained that it’s best to plant a wide variety of trees when replacing the lost ash trees, because if there’s an infestation of an invasive species that is highly destructive to one type of tree, it won’t have as big an impact.

“We want to be replacing them thoughtfully, with different kinds of species that mature at different times, and that we don’t have these massive losses,” she said.

The Morton Arboretum has a tree selector tool on its website to help you out. Scott said don’t just go with a popular species of tree.

“People ask for maple trees all the time, because of the beautiful fall color, but when you plant so many maple trees, we’re going to be in a lot of trouble,” she said.

Scott said the key is to consider the many other possibilities.