An arborist is a specialist in the care of individual trees. Arborists are knowledgeable about the needs of trees and are trained and equipped to provide proper care. Hiring an arborist is a decision that should not be taken lightly. Proper tree care is an investment that can lead to substantial returns. Well cared-for trees are attractive and can add considerable value to your property. Poorly maintained trees can be a significant liability. Pruning or removing trees, especially large trees, can be dangerous work. Tree work should only be done by those trained and equipped to work safely in trees. ISA Certified Arborist List Services That Arborists Can Provide

1. Pruning - The arborist can determine what type of pruning is necessary to maintain or improve the health, appearance, and safety of trees. These techniques include:

• Eliminating branches that rub each other.
• Removing limbs that interfere with wires, building facades, gutters, roofs, chimneys, windows, or that obstruct streets or sidewalks.
• Removing dead or weak limbs that pose a hazard or may lead to decay.
• Removing diseased or insect-infested limbs.
  
• Creating better structure to lessen wind resistance and reduce the potential for storm damage.
  
• Training young trees.
  
• Removing limbs damaged by adverse weather conditions.
  
• Thinning or removal of branches to increase light penetration.
  
• Improving the shape or silhouette of the tree.

2. Removal - Although tree removal is a last resort, there are circumstances when it is necessary. An arborist can help decide whether or not a tree should be removed. Arborists have the skills and equipment to safely and efficiently remove trees. Removal is recommended when the tree:

• Is dead or dying.
• Is considered irreparably hazardous.
• Is causing an obstruction that is impossible to correct through pruning.
• Is crowding and causing harm to other trees.
• Is to be replaced by a more suitable specimen.
• Should be removed to allow for new construction.

3. Emergency Tree Care - Storms may cause limbs or entire trees to fall, often landing on homes, cars, other structures, or other trees. The weight of storm-damaged trees is great, and they can be very dangerous to remove or trim. An arborist can assist in performing the job in a safe manner, while reducing further risk of damage to your property.

4. Planting - Some arborists plant trees and most can recommend what types of trees are appropriate for a specific location. The wrong tree in the wrong location could lead to future problems due to limited growing space, insects, diseases, or poor growth.

5. Other Services - Many arborists also provide a variety of other tree care services including:

• Practicing Plant Health Care; a concept of preventive maintenance to keep trees in good health, which will help the tree better defend itself against insects, disease, and site problems.
• Fertilization.
• Cabling or bracing for added support to branches with weak attachment.
• Aeration to improve root growth.
  
• Installation of lightning protection systems.
  
• Spraying or injecting to control certain insect and disease problems. Selecting the Right Arborist for the Job There are a variety of things to consider when selecting an arborist including:
  
  
  • Membership in professional organizations- such as the International Society of Arboriculture (ISA), the Tree Care Industry Association, or the American Society of Consulting Arborists (ASCA)-demonstrates a willingness on the part of the arborist to stay up-to date on the latest techniques and information.
    
    
  • Check in the phone directory yellow pages for those arborists who advertise as ISA Certified Arborists or display the official logo of the ISA Certified Arborist. Certified arborists are experienced professionals who have passed an extensive examination covering all aspects of tree care.
    
    
  • Ask for proof of insurance and then phone the insurance company if you are not satisfied. A reputable arborist will have personal and property damage insurance as well as worker's compensation insurance. Many homeowners have had to pay out large amounts of money for damages caused by uninsured individuals claiming to be a tree experts. You could be held responsible for damages and injuries that occur as a result of the job.
    
    
  • Some governmental agencies require contractors to apply for permits and/or to apply for a license before they are able to work. Be sure they comply with any local, state, provincial, or national law that governs their work.
    
    
  • Ask for references to find out where the company has done work similar to the work you are requesting. Don't hesitate to check references or visit other worksites where the company or individual has done tree work. Remember, tree care is a substantial, long-lasting investment; you would not buy a car without a test drive!
    
    
  • Unless you know and are comfortable with the arborist, get more than one estimate. You may have to pay for the estimates, and it will take more time, but it will be worth the investment.
    
    
  • Be wary of individuals who go door-to-door and offer bargains for performing tree work. Most reputable companies are too occupied to solicit work in this manner. Improper tree care can take many years to correct itself, and in some cases, it can never be corrected. Are you willing to take that risk with your valuable investment?
    
    
  • Good arborists will only perform accepted practices. For example, practices such as topping a tree, removing an excessive amount of live wood, using climbing spikes on trees that are not being removed, and removing or disfiguring living trees without just cause are unnecessary.
    
    
  • Don't always accept the low bid. You should examine the credentials and the written specification of the firms that submitted bids and determine the best combination of price, work to be done, skill, and professionalism to protect your substantial investment.
    
    
  • Get it in writing. Most reputable arborists will have their clients sign a contract. Be sure to read the contract carefully. Don't be afraid to ask questions, such as: - When will the work be started and completed? - Who will be responsible for clean-up? - Is this the total price? - If I would like more to be done, what is your hourly rate?
    
    
  • What Is a Certified Arborist? An arborist by definition is an individual who is trained in the art and science of planting, caring for, and maintaining individual trees. ISA Arborist Certification is a non-governmental, voluntary process by which individuals can document their base of knowledge. It operates without mandate of law and is an internal, self-regulating device administered by the International Society of Arboriculture. Certification provides a measurable assessment of an individual's knowledge and competence required to provide proper tree care. Certification is not a measure of standards of practice. Certification can attest to the tree knowledge of an individual but cannot guarantee or ensure quality performance. Certified arborists are individuals who have achieved a level of knowledge in the art and science of tree care through experience passing a comprehensive examination developed by some of the nation's leading experts on tree care. Certified arborists must also continue their education to maintain their certification. Therefore, they should be up-to-date on the latest techniques in arboriculture.

Developed by the International Society of Arboriculture (ISA), a non-profit organization supporting tree care research around the world and is dedicated to the care and preservation of shade and ornamental trees. For further information, contact: ISA, P.O. Box 3129, Champaign, IL 61826-3129, USA. E-mail inquires: isa@isa-arbor.com © 1995 International Society of Arboriculture. UPDATED JULY 2003. Back to top

Hiring an Arborist
Pruning large trees can be dangerous. If pruning involves working above the ground or using power equipment, it is best to hire a professional arborist. An arborist can determine what type of pruning is necessary to improve the health, appearance, and safety of your trees. A professional arborist can provide the services of a trained crew, with all of the required safety equipment and liability insurance.

There are a variety of things to consider when selecting an arborist:

• Membership in professional organizations such as the International Society of Arboriculture (ISA), the Tree Care Industry Association (TCIA), or the American Society of Consulting Arborists (ASCA).
• Certification through the ISA Certified Arborist program.
• Proof of insurance.
• A list of references (Don't hesitate to check.)
• Avoid using the services of any tree company that: - Advertises topping as a service provided. Knowledgeable arborists know that topping is harmful to trees and is not an accepted practice. - Uses tree climbing spikes to climb trees that are being pruned. Climbing spikes can damage trees, and their use should be limited to trees that are being removed.

Developed by the International Society of Arboriculture (ISA), a non-profit organization supporting tree care research around the world and is dedicated to the care and preservation of shade and ornamental trees. For further information, contact: ISA, P.O. Box 3129, Champaign, IL 61826-3129, USA. E-mail inquires: isa@isa-arbor.com © 1995 International Society of Arboriculture. UPDATED JULY 2003. Back to top