Don't quote me on this, but I don't believe so. I know in Ottawa county we don't need any type of license to do lawn care, so I would think that in Kent county you wouldn't need to have a license either. Honestly I haven't heard of licenses for this in any towns around here either.
Now if you start getting into design/build services you will need a license and if you get into fertilizing you will need a license. But for just mowing and general landscaping, you won't need a license.
'07 Chevy 2500HD
2010 John Deere Z925A 54" MOD
2011 John Deere Quik Trak 647A
John Deere walkbehind