What Is an Arborist? When to Hire One and What They Actually Do
An arborist is a professional who specializes in the care and maintenance of trees. Not a “tree guy with a truck and a chainsaw.” A certified arborist has passed an exam, logged years of field experience, and keeps up with continuing education in tree biology, disease diagnosis, pruning science, and risk assessment.
The difference matters. A trained arborist understands how a tree responds to cuts, which diseases are treatable, and which structural defects mean a tree needs to come down before it falls on your house. An unqualified tree worker might top your tree (destroying its structure), spread disease with dirty tools, or miss a crack that makes the whole tree a liability.
What does an arborist do?
Arborists provide services across the entire life cycle of trees:
Diagnosis and consultation. An arborist can identify diseases, pest infestations, nutrient deficiencies, and structural problems. If your tree looks sick, an arborist can tell you what’s wrong, whether it’s treatable, and what it’ll cost. This is the service most homeowners don’t know exists. A $150 consultation can save you thousands by catching problems early.
Pruning. Professional pruning for structure, health, clearance, or aesthetics. Arborists follow ANSI A300 pruning standards, which means they know the difference between proper thinning cuts and the destructive topping that unlicensed operators do. For specifics on how pruning should be done, see our seasonal pruning guide.
Tree removal. Taking down dead, dying, or hazardous trees safely. This often involves climbing with ropes, rigging sections down in pieces, and working around structures, power lines, and other trees. The cost of tree removal ranges from $400 to $3,000+ depending on size and complexity.
Tree risk assessment. Evaluating whether a tree is structurally sound or poses a hazard to people and property. Arborists trained in TRAQ (Tree Risk Assessment Qualification) use systematic methods to evaluate trunk decay, root damage, lean, and branch failure potential. This matters for insurance claims, property transactions, and municipal permitting.
Planting advice. Recommending the right tree for the right spot. An arborist who knows your soil, climate, and site conditions can steer you toward species that’ll thrive and away from ones that’ll fail or cause problems. Cheaper than buying a $300 tree, planting it wrong, and watching it die.
Pest and disease treatment. Applying treatments for tree boring insects, fungal infections like oak wilt, and other threats. Some treatments (trunk injections, soil drenches) require professional equipment and licensing.
Emergency response. After storms, arborists handle hazardous hanging limbs, fallen trees on structures, and damaged trees that might fail. If a tree is leaning on your house or tangled in power lines, this is not a DIY situation.
Certified arborist vs. tree trimmer
This distinction is the single most important thing in this article.
ISA Certified Arborist: Has passed the International Society of Arboriculture exam, which covers tree biology, diagnosis, pruning, soil science, safety, and tree identification. Requires three years of full-time tree care experience (or a degree plus experience) to sit for the exam. Must complete 30 continuing education units every three years to maintain certification.
Tree trimmer/tree service: Anyone with a truck, a chainsaw, and a business card. No exam, no continuing education, no standards. Some are skilled professionals who choose not to pursue certification. Many are not.
| ISA Certified Arborist | Unlicensed tree service | |
|---|---|---|
| Training | Exam + 3 years experience minimum | None required |
| Standards | ANSI A300 pruning standards | Variable |
| Insurance | Required by ISA ethics code | Often lacking |
| Continuing ed | 30 CEUs every 3 years | None |
| Tree biology | Tested and verified | Self-taught (maybe) |
The ISA certification isn’t a guarantee of quality, but it’s the best filter available. Would you hire an unlicensed electrician to rewire your house? Same logic applies to the person cutting 2,000-pound branches over your roof.
When to hire an arborist (vs. doing it yourself)
Hire an arborist when:
- Any branch is thicker than 4 inches at the cut point
- The work requires a ladder taller than 8 feet
- The tree is near power lines (ALWAYS call a professional)
- You see signs of disease or decay and don’t know the cause
- The tree is leaning, cracking, or showing structural problems
- You need a tree removed (chainsaws + gravity + lack of experience = hospital visits)
- Insurance or a real estate transaction requires a professional assessment
- You’re not sure whether a tree is dead or saveable. Our guide on how to tell if a tree is dead can help you do an initial assessment
Handle it yourself when:
- Pruning small branches (under 2 inches) within easy reach
- Removing suckers and water sprouts from the base
- Planting a new tree (following proper planting technique)
- Basic watering and fertilizing
- Cosmetic trimming of small ornamental trees under 15 feet
- Hedge trimming and shrub maintenance
How to find a good arborist
Step 1: Use the ISA “Find an Arborist” tool. Go to treesaregood.org/findanarborist and search by zip code. This returns only ISA-certified professionals in your area.
Step 2: Get at least three quotes. Prices vary wildly for the same work. Three quotes give you a reality check on what the job should cost.
Step 3: Verify credentials. Ask for their ISA certification number and verify it on the ISA website. Ask for proof of liability insurance and workers’ compensation insurance. If they can’t produce both, walk away.
Step 4: Ask for references. Any arborist worth hiring has a list of satisfied customers. Call at least two.
Red flags (walk away immediately)
- They want to top your tree. Topping is the single worst thing you can do to a tree. Any professional who suggests it is not a professional. Period.
- They go door-to-door after storms. Storm chasers prey on panicked homeowners. They do shoddy work, charge inflated prices, and disappear.
- No insurance. If an uninsured worker falls out of your tree and gets hurt, you could be liable.
- They want full payment upfront. Standard practice is 50% deposit, 50% on completion, or payment on completion for smaller jobs.
- They use climbing spikes on a tree they’re not removing. Spikes wound the tree. They’re only appropriate for removals, not pruning.
- They can’t explain what they plan to do. A good arborist walks you through the work before starting. “We’ll take care of it” is not a plan.
What arborists charge
Costs vary by region, tree size, and job complexity. These ranges reflect 2025-2026 pricing in most US markets:
| Service | Typical cost |
|---|---|
| Consultation/diagnosis | $75-200 |
| Pruning (small tree under 25 ft) | $150-400 |
| Pruning (medium tree 25-50 ft) | $300-800 |
| Pruning (large tree 50+ ft) | $800-2,000 |
| Tree removal (small) | $400-800 |
| Tree removal (medium) | $800-1,500 |
| Tree removal (large) | $1,500-3,000+ |
| Stump grinding | $150-400 |
| Tree risk assessment (TRAQ) | $150-500 |
| Emergency storm response | $300-1,500+ |
| Trunk injection (per tree) | $150-300 |
For a detailed breakdown of tree trimming costs and tree removal costs, we have separate guides.
How to become an arborist
If you’re considering arboriculture as a career, here’s the path:
Education: A degree isn’t required but helps. Associate’s or bachelor’s degrees in arboriculture, urban forestry, horticulture, or related fields are offered at many community colleges and universities. Some programs are specifically designed for ISA certification preparation.
Experience: You need three years of full-time experience in arboriculture to qualify for the ISA Certified Arborist exam. With a degree in a related field, the experience requirement drops to two years, and with a bachelor’s, one year.
ISA Certified Arborist exam: A 200-question multiple-choice test covering tree biology, diagnosis, pruning, soil science, tree selection, installation, safety, and urban forestry. Pass rate is roughly 70%. Study materials are available through the ISA.
Continuing education: 30 CEUs every three years to maintain certification. This keeps arborists current on new research, treatments, and safety standards.
Specializations:
- TRAQ (Tree Risk Assessment Qualification): Advanced training in evaluating tree hazards. Requires ISA certification first.
- Board Certified Master Arborist: The highest ISA credential. Requires 10+ years of experience and a rigorous portfolio review.
- Utility Arborist: Specializes in trees near power lines. Additional training through the Utility Arborist Association.
- Municipal Arborist: Works for cities managing public tree inventories. Often requires a degree plus certification.
Salary range: Entry-level ground workers earn $15-20/hour. Certified arborists with experience earn $50,000-80,000 per year. Consulting arborists and business owners can earn $100,000+. It’s physically demanding work with real safety risks, but arborists who love trees find it deeply rewarding.
Tree risk assessment: what it involves
A formal tree risk assessment is one of the most valuable services an arborist provides. Here’s what happens during a professional assessment:
Level 1 (Limited visual): A walk-by assessment covering many trees quickly. Used for park inventories, post-storm surveys, and large properties. Cost: $50-100 per property.
Level 2 (Basic assessment): A detailed visual inspection of one tree. The arborist walks around the tree, examines the trunk, root flare, scaffold branches, and canopy. Looks for cavities, cracks, fungal fruiting bodies, dead branches, lean, and root damage. This is what most homeowners need. Cost: $150-300.
Level 3 (Advanced assessment): Includes diagnostic tools like resistance drilling (Resistograph), sonic tomography, or aerial inspection. Used when Level 2 finds concerns that need quantification. How much decay is inside that trunk? Is there enough sound wood to support the tree? Cost: $300-500+.
The arborist assigns a risk rating and recommends action: monitor, prune, cable/brace, or remove. This documentation protects you legally. If a “low risk” tree later fails and damages a neighbor’s property, you’ve demonstrated due diligence. If a “high risk” tree fails after you ignored the recommendation to remove it, you’re in a weaker legal position.
The bottom line
You don’t need an arborist for every tree question. But for anything involving height, weight, disease, or structural concerns, a certified arborist is the right call. The $150 consultation fee is a fraction of what it costs to deal with a tree that was improperly pruned, a disease that was misdiagnosed, or a branch that fell on a car because nobody noticed the crack. For more on maintaining your trees between professional visits, check our spring tree care guide and mklibrary.com’s guide to yard maintenance basics.