Requirements vary by state and city, but liability and workers compensation insurance are the practical standard everywhere, because a homeowner can be exposed if an uninsured worker is injured on their property. Ask for a certificate rather than accepting a verbal claim.
Insurance is the practical standard everywhere, regardless of what licensing your jurisdiction requires.
The reason matters. If an uninsured worker is injured on a homeowner's property, or if a limb damages a neighbour's structure, the homeowner can find themselves exposed. That is why insurance is the first thing informed customers check and the first thing a tree service should state.
Two coverages to name explicitly:
Offer to provide a certificate on request rather than simply claiming coverage. Some operators say fully insured and mean a minimal policy. Being able to produce documentation separates you immediately.
On licensing, requirements vary considerably by state and city, and some jurisdictions regulate tree work specifically while others treat it under general contracting rules. Utility line clearance is frequently a separate qualification. Verify your own requirements with your state and municipal authorities rather than relying on general guidance.
From a marketing standpoint, putting this information near the top of the home page is one of the highest-return changes available in this trade, because it answers the customer's actual question before they ask it.
The Tree Service BrandPack is ready to use, fully customizable, and done for you, so you get all the marketing assets you need.