An arborist is a tree specialist who is trained in the art and science of cultivating individual trees. The International Society of Arboriculture (ISA) Arborist Certification is a non-governmental, voluntary process by which individuals can document their knowledge of arboriculture.

Arborist Certification requires a minimum amount of education, experience and passing a comprehensive examination on all aspects of tree care. Certified arborists must also obtain a minimum amount of continuing education units to maintain their certification. Certification attests to the minimum knowledge of the individual but does not guarantee or measure their standards of practice.

So, how does one go about hiring an arborist? The best source may be an acquaintance that uses an arborist with whom they are satisfied. Just the same, do not be timid about asking the arborist for documentation. Next, try the yellow pages under "Tree Service" or even search on-line. Certified arborists will proudly display their credentials because they have worked hard to attain them. Still, ask for their certification card or certification number. The validity can be checked on-line at www.isa-arbor.com or by calling ISA at (217) 355-9411.

Beware of doorknockers and flyers. These are particularly common after serious storms when non-professionals see an opportunity to make some quick money. Do not be rushed into a "bargain" and never pay any money up front.

Other items to consider when hiring an arborist are:

• Ask for certificates of insurance providing coverage for personal and property damage as well as Worker's Compensation. Worker's compensation is particularly important because many smaller companies advertise as "fully insured" but they do not carry this important protection for you. Be sure to call the insurance company to see that the insurance is still in force.
• Determine if the prospective arborists are members of professional organizations such as the International Society of Arboriculture and Tree Care Industry Association. Membership does not guarantee quality but the lack of membership indicates poor professionalism.
• Ask for some references. Call the clients to be sure that they were satisfied with the service and maybe even go by to look at some recent work.
• Consider having more than one arborist submit estimates for the work. Be sure that everyone submits their quotes for the same specifications. If trees are removed will the wood be hauled away or cut into firewood for your use? Will the stumps be ground out? Pruning may be the most difficult service to specify and you may the need the services of a consultant to write them.

• Tree Appraisal is a specialized process used to establish the value of trees and landscapes. It is used whenever the value of trees and landscapes must be established such as insurance claims, trespass and damage litigation, real estate appraisal, and income tax casualty deductions.
• Diagnosis of tree problems often must be accurately made before a proper course of treatment can be formulated.
• Site Development is a necessary part of new construction around trees that are to be saved. Our Consulting Arborist's expertise can help you architect to plan your home's layout and construction to minimize tree damage and we can prescribe treatments to help the trees survive the trauma of construction.
• Tree Risk Assessment is becoming more important. A detailed examination of your trees can be made to determine if any structural defects are present and how serious they actually are. If the situation warrants, we may bore a series of small probes into the trunk and/or limbs to locate any decay and determine it's extent. Such information is invaluable to prevent needlessly removing valuable trees and, conversely, to identify and mitigate hazardous trees.
• Tree Management Plans may be needed to ensure the health and longevity of trees and landscape plans. Our consultant can help formulate a plan within your budget that will maintain your trees in the best possible health.