The Army Corps of Engineers is banning firewood brought to Perry Lake from outside the immediate area.

It’s part of an effort to prevent the spread of a beetle that is killing ash trees.

Starting Friday, campers at Perry Lake in northeastern Kansas will be barred from bringing in firewood that did not originate in surrounding Jefferson County. The Corps is also banning all firewood from ash trees, no matter where it comes from.

The goal is to protect Perry Lake’s trees from the emerald ash borer beetle, which was recently detected in northwestern Missouri’s Platte County. The Corps says that’s the beetle’s western-most confirmed presence.

Visitors who bring non-native firewood to Perry Lake will be able to exchange it for native wood to use during their stay.