One city requires a initial exam (basic, but a lot of people don't pass) & a practical exam (trimming a city tree). After that they only require proof of Gen Liab Insurance and $25 dollar annual fee.
Another city simply wants $50/ year and a copy of Gen Liab.
A couple of city's require a certified arborist on staff and on site. If not, then you don't get licensed. And of course, proper Gen Liab Insurance.
If I were a municipality, I'd require the following:
-Proof of Gen Liab Insurance
-Proof of Workman's Comp Insurance
-ISA C.A. would be nice, but not fully required. However, a test upfront would be a start.
-Reasonable Annual Fee.
If I were a municipality, my expectations would be:
-First, to follow the above requirments
-One time per year on site evaluation. (To see how pruning standards are being done). More evaluations would be ideal, but people would whine too much.
-To not tolerate lion's tailing, topping, stubs, flush cuts, over thinning, etc...
-I would give a 2 strikes you're out rule. Why 2 strikes? Dunno. I sounds fun! I'd basically say, that the 1st strike is a warning. The second infraction means that they aren't going to cooperate. Therefore, they cannot be licensed. How long to suspend a license? Dunno. Maybe a year.
Bottom line, the municipality needs legal backing to enforce their own rules. The City of Longmont (my home town) has no legal "teeth" to enforce their own rules... It frustrates me.