It's quiet across the Village of Park Forest, but soon, it will be filled with the sounds of countless cicadas. 

Trillions of 13-year and 17-year cicadas, part of Brood XIX and Brood XIII, have been waiting for the right conditions to emerge in Illinois. Though trees across the Village will be covered in cicadas in the coming days, Park Forest Arborist Todd Cann said residents should know they must protect their young trees.

"They make slits and deposit eggs near the ends of branches, which causes this section of the branch to dry out and die—a phenomenon known as flagging," Cann said. "Healthy, mature trees aren't hurt by flagging. Young trees, on the other hand, can be seriously damaged or even killed by these cicada slits."

Cann said you can loosely wrap the branches in cheesecloth to protect young trees and keep female cicadas from using them as egg depository. If you see a lot of cicadas and then slits appear in your tree's branches, you should prune those branches within 6 to 10 weeks. This process removes the eggs before they hatch and moves underground to feed on the tree's roots. However, over-pruning may lead to the decline of the tree.

Though young trees are vulnerable to cicadas, mature trees can withstand the anticipated explosion of the insects.

To some, the cicadas may not be appealing and may be annoying. However, Cann said they are vital to the environment. 

"Cicadas are not dangerous and can provide some environmental benefits," Cann said. "Cicadas are a valuable food source for birds and other predators. Cicadas can aerate lawns, improve water filtration into the ground, and add nutrients to the soil as they decompose."