The State of Michigan’s Department of Environment, Great Lakes and Energy (EGLE) in an overview article of Part 91* indicates that:
“A permit is generally required for any earth change activity which disturbs one or more acres of land or which is within 500 feet of a lake or stream.”
So any vegetation removal that changes the earth, i.e. below the surface (roots, etc), generally requires a permit.
You can find more information of Part 91 at
*Soil Erosion and Sedimentation Control of the Natural Resources and Environmental Protection Act.