DETROIT (CBS DETROIT) –  Firefighters in northern Michigan and the Upper Peninsula have been busy fighting brush fires for the past week and a half that have been causing extensive damage. 

Dan Laux, fire prevention specialist with the Department of Natural Resources, said they’ve helped fight about 90 fires and he believes local departments have fought at least that many fires.

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“We did lose close to seven or eight structures total in a week — in a flurry of activities — anything from campers and motor-homes to out-buildings and sheds and houses and cabins,” he said.

Sources tell us a couple of firefighters were injured when a rotting tree fell on them and one broke his leg.

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Laux said most of these fires are caused by people having campfires or those burning debris, and then leaving the fires unattended.

He added permits are usually required for such fires.

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[For information about burn permits in Michigan, visit this link. For campfire safety tips from the state, click here].