PROOF OF INSURANCE ALWAYS COMES FROM THE INSURANCE COMPANY
A reputable tree service carries personal and property damage insurance ($1 million per occurence, $2 million aggregate) and worker's compensation insurance ($1 million). If a tree service is uninsured, homeowners could be held responsible for damages or injuries that occur as a result of the tree work. Request certificates, and phone the insurance agency to verify. Ask if the entire job will be performed by employees of the tree care company bidding the job. If not, ask for insurance certificates from all independent contractors as well.