GATLINBURG, Tenn. (AP) -- The Great Smoky Mountains National Park has another Citizen Scientist opportunity this coming weekend.

Park biologists and educators need 16 volunteers to help them map ash tree locations Saturday morning.

Ash trees are at risk from the Emerald Ash Borer -- an invasive beetle species that was discovered in Michigan in 2002. The insects have already killed tens of millions of ash trees in the Midwest.

Knowing where ash trees in the park are will help biologists detect future infestations.

Volunteers under 13 must be accompanied by an adult.

People taking part will hike about five miles and need to register by calling Ranger Susan Simpson at (865) 436-1200.

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