NASHVILLE, Tenn. (AP) — In an effort to prevent the spread of insects, Tennessee State Parks officials are warning people at campsites to use only heat-treated wood or wood collected nearby.

State forester Jere Jeter says the transportation of firewood is a reason for the introduction of harmful insects to Tennessee's woodlands. He says the biggest pest is the emerald ash borer, which has prompted a restricted movement on forest products in at least 44 of Tennessee's 95 counties.

Parks spokeswoman Kim Schoetzow says starting Wednesday, campers and other visitors will be advised to use packaged, heat-treated firewood available and camp stores and convenience stores.

She says dead wood found from the area near the campfire site and manufactured logs also can be used.