Thousands of Nashville trees infested with emerald ash borer

Why it matters: Infested trees in parks, many of which are along walking trails, are potential safety hazards because they are more likely to fall. Parks officials say this effort will reduce the risk to passersby or property.

Zoom in: The borer is an invasive metallic green beetle originally from northeast Asia. It was first discovered in the United States in Michigan in 2002.

• They kill ash trees by tunneling through the trunk and eating the tissue that pulls water up from the roots and distributes nutrients.

Flashback: The bug was first spotted in Tennessee in 2010. They made it to Nashville by 2014.

By the numbers: In a statement last year, the Tennessee Department of Agriculture estimated there were 240 million ash trees across the state, which represented a decline of about 20 million in 10 years.

What's happening: Infested trees in Nashville parks will be removed over the next six months. Many of the trees in question are marked with bright blue spray paint.

• The trees are spread across 51 park properties. The largest group of trees slated for removal is in Percy and Edwin Warner parks.

Be smart: The Parks and Recreation Department says thousands of trees in Nashville parks are infested. Infested trees will all die without early treatment. Officials urged residents to be mindful of infested trees.

• Signs include dying branches, D-shaped holes in the trunk, and woodpecker damage, because the birds feed on the bugs.