When should I call a certified arborist?

Call a certified arborist when the work cannot be done safely from the ground, when the cause of a problem is not obvious after the basic checks, or when a tree could hit a person, a house or a power line. For most other things, a few minutes of checking water, mulch and symptoms comes first.

Call right away

These need a professional, not a weekend.

• Anything near a power line. The USDA Forest Service's Tree Owner's Manual says never to prune trees or branches that are within 10 feet of utility lines, and to contact your local utility company instead.^[1] Virginia law also bars anyone working in a trade or business from placing a person, tool or ladder within 10 feet of an overhead high voltage line.^[2]
• Work that needs a ladder, climbing or a chainsaw. The manual says to hire an arborist if you cannot prune the tree with both feet on the ground, and if power equipment is required.^[1]
• A storm-damaged tree. The Virginia Department of Forestry says to watch for fallen, damaged, uprooted or leaning trees, because they can be extremely hazardous.^[3] It advises extreme caution when cutting them, or hiring a qualified arborist, tree care professional, or logger.^[3]
• An elm with bright yellow leaves on one or two branches. The manual lists this as Dutch elm disease and says to immediately call the university or an arborist.^[1]

Call when the cause is unclear

If you have checked soil moisture, pulled mulch back from the trunk and looked for the obvious, an arborist is the next step. The manual's troubleshooting chart says to call for advice from an arborist or a university plant diagnostic service for yellow or brown leaves, sparse leaves, spots on leaves, small leaves, wilted leaves, very little growth, and holes in the trunk or branches.^[1] A black clump on a cherry branch, which the manual lists as black knot, falls in the same category.^[1]

Other reasons to bring one in:

• Signs of structural trouble. The manual lists an encircling root compressing the trunk, and a recent lean where the soil or grass has lifted on one side, among the things to check yearly, and says if anything is found, or if in doubt, contact an arborist.^[1]
• Construction near the roots. The manual tells you to consult an arborist about methods to protect the roots if work is planned near them.^[1]
• Fertilizer or spray decisions. The manual says to apply nitrogen fertilizer ONLY if diagnosis by an arborist indicates that it is necessary.^[1]
• Tree removal. An arborist can say whether a tree really needs to come down. See how to tell if a tree is dead or dangerous first.

You can often wait

Some things look alarming and are not. The manual lists squirrel damage, webs in the branches from fall webworm or Eastern tent caterpillar, holes in leaves from insect feeding, and sooty mold on sticky leaves as not worth worrying about for the tree's health.^[1] It says to hose the sooty leaves down to get rid of the sap.^[1] For a mildly off-color shrub, start with how to treat a sick tree, which walks through the checks an arborist would do first.

If you are unsure, the Virginia Department of Forestry has certified arborists on staff who can answer tree care questions, and it points you to your local DOF forester to reach them.^[4]

What a certified arborist should show you

The Virginia Department of Forestry says arborists prioritize safety and follow the standards of proper tree care known as ANSI A300, and must take continuing education to maintain their certification.^[4] The Tree Owner's Manual says certified or state-licensed arborists are experienced professionals who have passed an examination and meet requirements for on-going education.^[1]

Ask for the certification number, then ask for proof of insurance. The manual says a reputable arborist carries personal and property damage insurance ($1 million per occurrence, $2 million aggregate) and worker's compensation insurance ($1 million), and that you should request certificates and phone the insurance agency to verify.^[1] Get the scope and the price in writing; what an arborist costs in Virginia explains how to compare bids.

Certification is not the same as a contractor licence. The Board for Contractors' list of specialty services has no tree-care, tree-removal or arborist specialty,^[5] and whether tree removal companies need a licence depends on the work. If a bid includes spraying, anyone who uses any pesticide on someone else's property for pay must be a certified commercial applicator working for a company with a Pesticide Business License.^[6]

Stop and call a pro if

• A limb or trunk is cracked, hanging or leaning toward a house, driveway or play area.
• Any part of the tree is touching or near a service line. Call the utility first.
• A salesperson is at your door after a storm. The manual notes that door-to-door sales are especially common after storms, and that good arborists perform only accepted practices and wear safety equipment.^[1]
• A bidder proposes topping the tree. The manual lists topping a tree and using climbing spikes for pruning as unacceptable.^[1]

Getting help in Virginia

Browse lawn and landscaping answers or tree and shrub health services. When you want an arborist to look at the tree, describe the problem once and local businesses quote it.