Michigan urges travelers to leave firewood at home

Michigan officials are urging hunters, campers and other fall travelers to leave untreated firewood at home to help prevent the spread of invasive insects and tree diseases.

The warning comes during October’s Firewood Month and ahead of a statewide restriction on incoming firewood that takes effect Jan. 1, 2027.

Under the Michigan Department of Agriculture and Rural Development’s External Firewood Quarantine, only heat-treated, certified firewood will be permitted to enter Michigan.

Untreated firewood can carry insects, eggs and disease-causing fungi, even when it appears clean and healthy, according to the Michigan Invasive Species Program. Moving it can introduce forest pests to areas hundreds of miles from an existing infestation.

Firewood movement helped spread the emerald ash borer throughout Michigan, where it has killed an estimated 40 million trees since 2002. Oak wilt, a fungal disease that can kill oak trees within months, also can spread through infested firewood.

Spotted lanternflies, now present in the southern Lower Peninsula, can travel on firewood or lay egg masses on it, potentially accelerating their spread north. Other threats include the Asian longhorned beetle and mountain pine beetle, which could be transported into Michigan.

To increase the availability of safer firewood, the state launched a certification program in 2026. Producers can have their operations certified to verify that wood receives heat treatment at temperatures and durations sufficient to kill invasive insects and pathogens.

Michigan-certified firewood will carry a state seal equivalent to the certification provided by the U.S. Department of Agriculture for heat-treated firewood.

Officials recommend buying certified, heat-treated wood or purchasing or collecting firewood at the destination. Untreated wood should remain within 10 miles of where it was cut.

Seasoning or drying firewood does not eliminate the risk. Research cited by the program found that insects continued to emerge from wood three years after it was cut.

Travelers also should leave unused firewood at their destination rather than taking it home or to another campsite.

More than half of Michigan is forested, with an estimated 14 billion trees. The Michigan Invasive Species Program is partnering with DontMoveFirewood.org during Firewood Month to encourage choices that protect those resources.