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Extension > Garden > Trees and shrubs > How to hire a professional arborist to help care for your landscape trees

How to hire a professional arborist to help care for your landscape trees

Jeff Hahn and Gary Johnson, University of Minnesota Extension

There are many insect, disease, and abiotic problems that can threaten your urban landscape trees. Professional arborists are trained to provide proper care, help maintain healthy trees and provide management when necessary. Their expertise may include planting, transplanting, fertilizing, pruning, tree removal, and pest management, especially proper diagnosis of problems and pesticide application.

Gary Johnson

Experienced and skillful tree workers not only care for trees in the best manner, they work safely and reduce the risk to property damage during the tree care activity

Gary Johnson

With extra large trees, the danger involved with removing them becomes extra dangerous. Specialized equipment and skillful workers are absolutely essential when large trees in urban spaces must be removed.

Ben Johnson

Only experienced, licensed and insured tree care professionals should be allowed to remove storm damaged trees from homes to prevent additional damage to homes.

Gary Johnson

Evaluations of the condition of trees and their relative safety should only be done by experienced, licensed and certified tree care professionals

Where can I find a professional arborist?

A good place to start is the internet. Type in a city and keywords into a search engine, e.g. Google. You can also look online at the Urban and Community Forestry site for a variety of tree-related resources, including tree care companies in your area. (Note: This web page is a dynamic site that is updated on a regular basis. This site is primarily a listing of companies in Greater Minnesota). Many companies have web sites which will provide more detailed information about them.

You can also use the yellow pages of your telephone book. Look under arborist, tree care, or tree service for companies listed in your area. Many community municipal offices will provide a list of licensed tree care companies that provide service to the city as well as to private residences. Contact the parks and recreation department or public works to see if a list exists and is public information.

What qualifications should an arborist have?

Regardless of where you look, particularly consider companies whose arborists are certified by or are members in professional organizations.

A professional arborist should be certified through one or more international, national, or local organizations. Many arborists in Minnesota are certified through ISA (International Society of Arboriculture) and MSA (Minnesota Society of Arboriculture). An ISA/MSA certified arborist has a minimum of three years experience in some aspect of tree care and/or a college degree in horticulture, forestry, landscape architecture or urban forestry, and has passed an exam covering all aspects of tree care. You can search for certified ISA/MSA arborists at the International Society of Arboriculture web site.

Professional arborists may also belong to the American Society of Consulting Arborists (ASCA), the Minnesota Nursery Landscape Association (MNLA), or the Minnesota Turf and Grounds Association (MTGF). They may also possess the Tree Care Industry Association (TCIA) accreditation as a professional arborist.

Additionally, most cities in Minnesota require arborists to be licensed by the respective city if the company wishes to perform tree work within the city limits. Licensing only means that the various tree care companies have paid an annual licensing fee and have shown proof of insurance. Licensing in Minnesota does not imply proficiency. To that end, many communities are requiring that tree care companies working on publicly-owned trees employ ISA Certified Arborists in addition to registering with the community as a licensed tree care company.

Maintaining a membership demonstrates a willingness on the part of the arborist to stay up to date on the latest techniques and information. Membership in these and other professional organizations does not guarantee quality, but does indicate professional commitment.

Consulting arborists

If you need to talk to someone about what is wrong with your tree, there are several options. Consulting arborists are especially trained and experienced in the assessment and diagnosis of tree problems, including pest issues. Consulting arborists may be private individuals or be affiliated to a tree care company.

Similarly, a number of cities employ city foresters or tree inspectors who are often certified arborists. They typically work in the parks and recreation or public works departments. They can help diagnose a tree's problem and will also offer advice on tree care and management. Contact your city local services to determine whether your city employs a city forester. Tree Inspectors are certified by the Minnesota DNR (Department of Natural Resources). All tree inspectors must pass an exam covering certain aspects of tree care and management.

Pesticide applications

A professional arborist that applies a pesticide to a tree for hire needs to be licensed by the state of Minnesota. They are required to have a category E, Turf and Ornamental license issued by the Minnesota Department of Agriculture (MDA).

All pesticides that can be applied to trees need to be registered by the Environmental Protection Agency (EPA) and with the state of Minnesota. All applicators must follow the label and only apply the pesticide at sites and plants listed on the label. Only licensed applicators can use restricted use pesticides.

General guidelines for selecting a professional arborist.

  1. Ask for certificates of insurance, including proof of liability for personal and property damage and worker's compensation. Then, contact the insurance company to make sure the policy is current. Under some circumstances, you can be held financially responsible if an uninsured worker is hurt on your property or if the worker damages a neighbor's property.
  2. Ask for local references. Take a look at some of the work, and if possible, talk with former clients. Experience, education and a good reputation are signs of a good arborist.
  3. Don't rush into a decision just because you are promised a discount if you sign an agreement now. Be sure you understand what work is to be done for what amount of money. Do not feel obligated to pay in full until the work is completed, but keep in mind that terms for residential tree work are usually "due on delivery," and work may not proceed unless you are there to pay. A reasonable down-payment may be expected if materials are part of the contracted work. Examples of material expenses could include tree preservation fencing and signage, mulching, transplanted or purchased trees.

    Ask the tree care company to create a specific contract for work, including all costs and tasks associated with the work. For pruning, use current language that is consistent with industry standards. Consult the Forest Service publication "How to Prune Trees," for those standards, http://na.fs.fed.us/spfo/pubs/howtos/ht_prune/htprune-rev-2012-screen.pdf.

  4. The contract should include the responsibility for clean-up and disposal of tree wood residue and any issues that apply to timing of the work and the potential to contract or spread tree diseases or insect pest problems.
  5. If possible, get more than one estimate.
  6. Good work is not inexpensive. A good professional must carry several kinds of insurance as well as pay for specialized equipment. You are also paying for their experience and understanding of how to care for trees and their ability to provide long term value to your landscape trees. Beware of estimates that fall well below the average. There may be hidden costs or the person may not be fully insured or trained.
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