Why Hire an Arborist?
Reasons You May Need a Consulting Arborist
Arborist Qualifications
Insurance
Get a Written Bid
A Few Cautions
A List of Local Arborists

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Canopy: Trees for Palo Alto is a non-profit advocate for Palo Alto's trees that works to educate, inspire and engage Palo Altans as stewards of new and existing trees.  Canopy developed a list of arborist services and information on how to hire an arborist in response to many questions from local residents.  The list is not intended to be a statement of qualification or endorsement of particular companies, but rather an easy reference for Palo Alto residents beginning the process of contacting arborists for services. 

You may want to hire an Arborist if you want to:

• Train or prune young trees 2, 5 and 10 years of age to develop strong structure
• Protect existing trees from construction damage
• Correct damage, remove dead and diseased wood
• Control size, thin to allow more light beneath, and improve wind/storm resistance
• Remove excessive weight at branch ends
• Do a preventive health/safety check-up, usually 5-10 years between check-ups
• Diagnose for pests and diseases, determine fertilization needs
• Choose the right tree for your site or transplant existing trees to better locations
• Remove a tree or grind out a stump

Arborists are professionals trained in the art and science of planting, caring for and maintaining individual trees.  Arborists can be members of a number of professional organizations including the International Society of Arboriculture (ISA), or the American Society of Consulting Arborists (ASCA).  Arborists certified by the ISA are experienced arborists who have passed an extensive examination on all aspects of tree care and demonstrated at least three years of professional experience.  Certified arborists must also maintain their certification through continuing education.

You may need a Consulting Arborist if you want to:

• Assess tree safety to protect structures such as houses
• Appraise the value of a tree
• Diagnose and recommend treatment for a problem
• Get a “second opinion” to help you decide on tree work
• Have a legal expert in a court case

Consulting Arborists are highly trained experts who charge a fee for their advice. They may refer you to other arborists who will perform the service based on the consultant’s recommendations. Members of the American Society of Consulting Arborists (ASCA) meet a number of requirements including at least five years professional experience and a four-year degree (or equivalent) in arboriculture and related fields. Members must also maintain their certification through continuing education. A Registered Consulting Arborist (RCA), a class of membership, involves graduation from the Arboriculture Consulting Academy and an increased number of Continuing Education Units (CEUs.)

Selecting an Arborist

Qualifications

Not all arborists possess the skills and qualifications discussed above.  Interview an arborist before hiring to determine their qualifications and service specialties.  Discuss the reasons why you think a tree needs service.  Listen to their opinions and recommendations.  A competent arborist will not agree to perform work that they believe is unsafe or horticulturally unsound.

Canopy recommends hiring an ISA-certified arborist or a consulting arborist who is a member of the ASCA.  Arborists should agree in writing to perform all tree work to ANSI A300 Standards. (ANSI A 300-Part 1, 2001 are the standard practices for care of trees, shrubs and woody plants put out by the American National Standards Institute) Even if a company is an ISA member, you should determine whether an ISA-certified arborist would be present to perform or oversee all work.  You may ask to see an individual’s white ISA card as proof.  Additionally, it is best to use an arborist who is familiar with the trees and ordinances of the City of Palo Alto or the municipality where the work will be performed.

To locate a certified arborist in your area, or to verify a certification, search the ISA directory at:

http://www.isa-arbor.com/arborists/arbsearch.html

To locate a consulting arborist in your area, or to verify membership, search the ASCA directory at: http://www.asca-consultants.org/directory/index.cfm

As a further consumer protection, you may wish to determine whether the tree company you select to perform work has a valid California Contractors License.  In California, some tree work including trimming, tree removal or planting requires a license if the job costs $500 or more for materials and labor.  Services such as consulting and pesticide application do not require a contractors license.

Verify the status of a contractor’s license by contacting the Contractors State License Board at telephone (800) 321-CSLB, or at the web site, www.cslb.ca.gov. Information on complaints and legal actions against the company can also be obtained from the Contractors State License Board.

Insurance

Ask to see insurance certificates as proof of liability for personal and property damage and workmen’s compensation.  These are two separate types of insurance and both should be disclosed to you.  Phone their agent to verify current status and amount of coverage ($300K to $1M recommended).  Under some circumstances YOU can be held financially responsible if an uninsured worker is hurt on your property or if your neighbor’s property is damaged.

Get a Written Bid

Ask over the phone if you will be charged for an estimate before setting-up an appointment.  Remember that you will always be charged a separate consulting fee for advice not associated with the work being bid on.

Ask two or more arborists to write a bid, including:

• Timeframe for work and project completion.
• Detailed description of work to be performed for each tree.  Example: “Prune all dead, dying, diseased and weak branches 1-1/2 inches or greater in diameter.”
• Statement that work will be supervised by an ISA certified arborist to A.N.S.I. A300 Standards and/or that Western Chapter ISA Certified Tree Workers will be performing the work. 
• For insect or disease control, details of specific pests to be treated; what the manufacturer recommends for safe and effective use of the pesticide and their qualifications to make the recommendations and applications. 
• In Palo Alto, call the Santa Clara County Division of Agriculture at (408) 918-4600 or visit their web site at http://www.sccgov.org for more information on pesticides.
• For fertilizing: the name of the fertilizer, the grade and the rate and method of application.
• Cleanup procedures should be described and whether wood will be cut into fireplace lengths or hauled.
• The total dollar amount to be charged.  Work is usually bid as a fixed price for the entire job or billed on an hourly basis plus materials.   If the bid uses an hourly rate, ask to have the phrase “...but not to exceed $___...” included in the written bid.
• Clarify if the tree removal bid includes: Who will obtain tree removal permit, cost of grinding out the stump and surface roots (to what depth), hauling the stump chips, filling with topsoil, and replanting a new tree.

A Few Cautions

• If a dispute arises or you would like an expert to check the quality of work, seek the services of a consulting arborist, your city arborist, or a similar specialist who is not in competition with the arborist you hired.
• NEVER allow a tree to be “topped.” Topping is the practice of cutting large limbs off a tree or “stub cutting” in the wrong spot, removing too much of a tree’s foliar canopy at once.  Qualified arborists will refuse to “top” a tree, instead they will suggest moving, correctly pruning or replacing a tree that is wrong for the spot.

People who top trees (or ask to have this work done) give the following reasons: size reduction, regular maintenance trimming, safety pruning, allowing for overhead clearance beneath roof eaves, phone lines, etc.

But topping will not accomplish these goals.  Instead, it will: 

• Create a regular job for a “tree service” to return again in a couple of years since new branches will grow very quickly and the tree will regain its original height — and a fuller density;
• Weaken and possibly kill the tree; and
• Make the tree dangerous by causing new, weakly attached branches to sprout unnaturally as the tree tries to recover from over-pruning.  Such branches cannot hold much weight and may break off without warning, especially when they are large.
• A qualified arborist can explain to you the difference between “topping” and certain training styles where trees are severely pruned on a regular basis to attain a specific form such as “pollarding” or to accomplish “crown renovation.”
• A good arborist will never use climbing spikes unless the tree is to be removed.
• Off-the-street sales pitches or companies without a listing in the phone book or certification are often honest, hard-working people who do not understand why they lack the qualifications to give advice about trees. Don’t be scared into removing a tree by an unqualified person giving you an opinion that the tree is “dangerous.”
• References tell you a lot about customer satisfaction and can be helpful regarding the quality of cleanup work.  However, unless the referral is from an arborist, it will not necessarily be an accurate evaluation of an arborist’s qualifications or work quality.
• Mature trees contribute up to 15% of your property’s value.  Unsound work can cost money and create a dangerous hazard that is unseen by an untrained eye. 

A well-pruned tree, like a good haircut, at first glance often looks like no work was done at all, even after an arborist has spent many hours removing numerous carefully selected branches.        

This publication was funded by the California ReLeaf 2003 Capacity-Building Grant Program and the California Department of Forestry and Fire Protection.    

ARBORIST SERVICES

Canopy is not able to comprehensively assess or recommend businesses providing tree services.  Recipients of this list of arborists should carefully assess the ability of any service provider they contact to meet their needs.  Please see the attached guidelines “How to Hire an Arborist.” Canopy reserves the right to remove any company from the list at any time.

Arborists included here have requested that Canopy list their services.  Note that many arborists provide consulting services as well as pruning, planting, pesticide application, fertilizing, tree moving, removal and stump grinding. Please contact them directly to determine what services they provide.

Tree Services

*  also provide consulting services

Consulting Services Only

Tree Moving

Stump Removal

Please contact Canopy to request inclusion on this list of Arborist Services. Canopy reserves the right to refuse to publish any company or remove any currently published company at Canopy’s discretion.