An ISA Certified Arborist is the person who tells you whether a tree is actually dangerous, what is wrong with it, and what it will take to fix — before anyone starts a saw. Pacific Arboriculture keeps six ISA Certified Arborists on staff, and every credential below can be verified independently in about a minute. We inspect trees, assess risk, diagnose decline, and write the documentation cities and insurers ask for, across Auburn, Kent, Federal Way, Renton, Tacoma, Puyallup and the surrounding South Puget Sound.
Free on-site assessment · Written arborist reports available when a city, lender, or insurer needs documentation
What an ISA Certified Arborist Actually Does
The International Society of Arboriculture credential is earned by exam and maintained through continuing education. It is not a business license, and it is not something a company can buy. Here is the work our arborists do that a general tree crew is not trained to do — for residential, commercial, development, and municipal clients alike.
Tree Risk Assessment
A structured inspection of the trunk, root collar, union points, and target zone below the tree. We rate the likelihood of failure and the consequence if it happens, so a decision to remove or retain is defensible rather than a guess.
Tree Health Diagnosis
Thinning canopies, dieback, cankers, borers, and root disease all look similar from the driveway. An arborist identifies the actual agent and whether the tree is recoverable — the tree doctor role, before treatment is prescribed.
Written Arborist Reports
Permit applications, development review, right-of-way disputes, and insurance claims usually require a signed report from a credentialed arborist rather than an estimate on letterhead.
Tree Preservation & Construction
Root protection zones, grade-change impacts, and what a tree can survive when a driveway, addition, or utility trench goes in next to it. The least expensive time to involve an arborist is before the excavator arrives.
Pre-Purchase & Real Estate Inspections
Before you close, an arborist tells you what the trees on the property are going to cost you. Hazard trees within striking distance of the house, deferred pruning, root damage from past construction, and species that will outgrow their space — documented in writing while you still have negotiating room. Buyers, sellers, and agents all order these.
Tree Inventories & Municipal Consulting
Tagged, condition-rated inventories for cities, campuses, HOAs, and development sites, with maintenance priorities and a retention or removal recommendation per tree. This is the baseline document a jurisdiction or property manager budgets from.
Need the written document itself? See arborist reports and consultations. Need treatment rather than a diagnosis? See plant health care.
How an Arborist Inspection Works
Most consultations are straightforward. Here is what happens between your first call and a decision you can act on.
Free Consultation Booked
Call or send the form. We confirm the address, what you are seeing, and whether anything is urgent enough to need same-week attention.
On-Site Inspection
An ISA Certified Arborist walks the tree and the site — root collar, trunk, scaffold branches, canopy, and whatever is underneath it. No charge for the visit.
Findings Explained On the Spot
You get a plain answer: the tree is fine, the tree needs work, or the tree needs to come down. We tell you which, and why, while we are standing there.
Written Report If You Need One
If a city, HOA, lender, or insurer needs documentation, we quote a written report separately. If you only need work done, you do not need one.
Work Scheduled Only If Warranted
We are a working tree company, so we can carry out the recommendation — but a retain-and-monitor answer is a legitimate outcome and we give it regularly.
How to Verify a Certified Arborist
“Certified”, “licensed”, and “insured” are three separate things and only one of them is an arborist credential. Open the panels below to check ours, or anyone else’s.
Certified arborist vs. licensed tree serviceTwo different checks
A Washington contractor license is a registration with Labor & Industries. It proves a company carries a bond and insurance. It says nothing about tree biology, and any company doing tree work is required to have one. Ours is PACIFA*813KG, verifiable at L&I’s contractor lookup.
An ISA Certified Arborist credential is individual, not corporate. It is held by a person who passed the exam and keeps it current with continuing education. A company can be fully licensed and insured with nobody on payroll who holds one — which is why the two questions to ask are “are you licensed?” and “which of your people is ISA certified, and what is the certificate number?”
Pruning standards matter too. Work specified to ANSI A300 is the industry standard for how cuts are made; ask whether a proposal references it.
Verify any certificate number in under a minuteISA public directory
ISA publishes a public directory of everyone holding a current credential. Search a name or a certificate number at the ISA certificate directory and you will see the credential and its status. If a company cannot produce a number that resolves there, treat the claim as unverified.
All six of our arborists are listed further down this page with their certificate numbers linked directly to their ISA records. Details of the credential itself are published by ISA.
What TRAQ adds on top of certificationRisk assessment qualification
Tree Risk Assessment Qualification is a separate ISA qualification focused specifically on evaluating hazard. It trains an arborist in a repeatable method — identify the target, assess the likelihood of failure, assess the likelihood of impact, rate the consequence, and document the result — so two qualified assessors looking at the same tree reach comparable conclusions.
It matters most when the answer is contested: a neighbor dispute, an insurance claim, a city questioning whether a tree was genuinely hazardous, or a property manager who needs a record that risk was evaluated properly rather than eyeballed. When a hazard call needs to hold up in writing, TRAQ methodology is what makes it defensible.
Trees adjacent to power lines: we work on them, but we do not perform utility line clearance. If a limb is contacting a conductor, that is a call to the utility first.
Frequently Asked Questions About Certified Arborists
How do I know if a tree is actually dangerous?
Some signs are visible from the ground: a lean that has changed, soil heaving or cracking on one side of the root plate, mushrooms or conks at the base, a large cavity, deadwood in the upper canopy, or a co-dominant union with a visible crack. Any of those is worth an inspection. But plenty of hazardous trees look fine from the driveway, and plenty of alarming-looking trees are structurally sound. A tree risk assessment by an ISA Certified Arborist evaluates the likelihood of failure alongside what is underneath the tree — a fir over a bedroom is a different situation from the same fir over an empty back corner of a lot.
Is the arborist consultation actually free?
Yes. An on-site visit from one of our ISA Certified Arborists to inspect a tree, explain what we find, and quote any work is free anywhere in our service area, with no obligation to book. What is not free is a written arborist report — that is a separate paid deliverable, starting at $400 for residential and right-of-way reports and $800 for commercial and development reports. If you only need work done, you do not need a report.
Will my insurance pay to remove a hazardous tree?
Usually not on its own. Most homeowners policies cover tree removal after a tree has fallen and damaged a covered structure, not preventive removal of a tree that is merely likely to fail. The common exception is when an insurer or lender has flagged the tree themselves and asked for documentation, in which case a written assessment from a credentialed arborist is what they want to see. Policies vary considerably, so ask your carrier what they require before you commission anything — then we can write to that requirement.
Do I need an arborist report to get a tree removal permit?
It depends on the jurisdiction and the tree. Many South Sound cities allow a limited number of removals per lot per year with no permit and no report. Reports are typically triggered by larger or landmark-size trees, critical areas such as wetlands, stream buffers and steep slopes, development and short-plat review, or a claim that a tree is hazardous. We check the current code for your address before quoting and tell you whether a report is actually required. A report documents conditions and supports an application — it is not an approval, and the permit decision rests entirely with the jurisdiction.
What is the difference between a tree health assessment and a tree risk assessment?
A health assessment asks whether a tree is thriving: what is causing dieback, decline, discoloration, or poor growth, and whether it can be treated. A risk assessment asks a different question — how likely is this tree, or part of it, to fail, and what would it hit. A tree can be in poor health and pose almost no risk, and a vigorous tree with a structural defect over a driveway can pose a great deal. We often do both in one visit, but they are separate evaluations with separate conclusions.
Can an arborist save a tree that is already declining?
Sometimes, and it depends entirely on the cause. Decline from compacted or buried root collars, drought stress, girdling roots, poor prior pruning, or a treatable pest or pathogen often responds well to intervention. Decline from advanced root or butt rot, or from root loss to trenching and grade change, generally does not — the tree may hold on for years but the structural problem is permanent. The honest answer comes from diagnosis first. We will tell you when a treatment plan is worth the money and when it is not.
Should I get a tree inspection before buying a house?
It is worth doing whenever the property has mature trees close to the house, the driveway, or a property line. An ISA Certified Arborist walks the trees during your inspection window and tells you which ones are sound, which ones need work, and which ones are a removal you will be paying for within a few years. Hazard trees, past construction damage to root zones, and species planted too close to structures are the three findings that most often change a buyer’s number. Sellers order them too, to document that the trees are healthy before a buyer’s inspector raises the question. The on-site visit is free; a written version you can hand to a lender or a title company is quoted as a report.
What cities do we service?
Pacific Arboriculture works across south King County and north Pierce County from our shop in Auburn. These are the 21 communities we serve and the ZIP codes they cover.
King County
- Auburn — 98001, 98002, 98092
- Kent — 98030, 98031, 98032, 98042
- Federal Way — 98003, 98023
- Renton — 98055, 98056, 98057, 98058, 98059
- Fairwood — 98058
- Covington — 98042
- Maple Valley — 98038
- Burien — 98146, 98148, 98166, 98168
- SeaTac — 98148, 98158, 98168, 98188, 98198
- Tukwila — 98108, 98168, 98178, 98188
- Des Moines — 98148, 98198
- Normandy Park — 98148, 98166, 98198
- Pacific — 98001, 98047
Pierce County
- Tacoma — 98402, 98403, 98404, 98405, 98406, 98407, 98408, 98409, 98418, 98421, 98422, 98443, 98444, 98445, 98446, 98465, 98466
- Puyallup — 98371, 98372, 98373, 98374, 98375
- Fife — 98424
- Milton — 98354
- Sumner — 98390, 98391
- Edgewood — 98371, 98372
- Bonney Lake — 98391
- Lake Tapps — 98391
Several of these communities share a ZIP code with a neighbor, so seeing the same number twice is normal. Puyallup includes South Hill, and the Tacoma list covers the Midland, Summit and Parkland areas. Not sure whether you are in range? Call (206) 909-2170 with your address and you will get a straight answer. City-by-city detail is on the areas we serve page.
Talk to an ISA Certified Arborist
If you are not sure whether a tree is a problem, that is exactly the call to make. We come out, look at it, and tell you what we see — no charge and no obligation to have work done.
What an Arborist Consultation Costs
There are two different things people mean by “arborist consultation”, and they are priced very differently.
An on-site consultation to look at a tree and quote work is free. One of our ISA Certified Arborists comes to the property, inspects the tree, explains what is going on, and gives you a written estimate for any work that is warranted. There is no fee for that visit anywhere in our South Puget Sound service area, and no obligation to book. A $500 minimum applies to tree service work booked as a standalone visit; smaller pruning is usually folded into a larger project.
A written arborist report is a separate, paid deliverable. If a city permit application, development review, lender, HOA, or insurer needs signed documentation, that is a research and writing engagement rather than a site visit. Residential and right-of-way reports start at $400. Commercial, development, and municipal reports, which typically involve tree inventories, protection-zone plans, and code citations, start at $800. Pre-purchase and real-estate inspections are quoted the same way: free if you only need a verbal read on the trees, priced as a report if you need something you can hand to a lender, a seller, or a title company. Final pricing depends on tree count, site complexity, and the jurisdiction’s submittal requirements. A report documents conditions and supports an application — it is not an approval, and the permit decision rests entirely with the jurisdiction.
Looking for removal or pruning prices instead of consultation pricing? The tree removal cost estimator breaks pricing down by tree size, and arborist reports and consultations covers report scope in full.
What Our Arborists Look For in South Sound Trees
Douglas-fir dominates much of the South Puget Sound, and the most damaging disease of young-growth Douglas-fir in the Pacific Northwest is laminated root rot, caused by Coniferiporia sulphurascens. It spreads by root contact and persists for years in infected stumps and large roots left in the soil, so a lot cleared decades ago can still carry it. What makes it matter for a risk assessment is the timing: west of the Cascades, affected trees are frequently wind‑thrown before crown symptoms are obvious from the ground. Western redcedar and the native pines are tolerant and maples and alders are immune, which is why what goes back in the hole belongs in the report rather than in an afterthought.
Soil shapes risk here as much as species does. On the Green River valley floor through Kent and the low ground toward Renton, the soils are poorly drained silt loams and groundwater commonly sits within ten feet of the surface, with a seasonal high water table one to three feet down from November through April. That confines effective rooting depth. A shallow‑rooted mature conifer standing on saturated ground is the classic winter failure we get called out to after a windstorm, and it is why a February inspection on the valley floor reads differently than the same tree in August.
Puyallup shows how quickly this changes inside one neighborhood. On the river terraces, high‑terrace Briscot loams hold water within a foot of the surface, Sultan silt loams two to four feet down, and Puyallup fine sandy loam a short distance away is well drained past six feet. Two trees on the same street can be sitting on completely different root systems. Inspections in Auburn, Federal Way, Tacoma and Maple Valley run the same protocol either way: species, site, soil, target, and history, all documented before anything gets recommended.
Pathology and soil references: WSU Hortsense, the PNW Plant Disease Management Handbook, and USGS groundwater surveys of the Green River valley.
Meet Our ISA Certified Arborists
Every certification number below links to that arborist’s credential record with the International Society of Arboriculture, so you can verify it before anyone sets foot on your property.
Washington L&I Contractor License PACIFA*813KG · WSDA Pesticide Applicator #109480 · $1M liability insured
Schedule a Tree Inspection
Six ISA Certified Arborists, every certificate number verifiable, and a straight answer about whether your tree needs work. Serving Auburn, Kent, Federal Way, Renton, Tacoma, Puyallup, Maple Valley and twenty-one South Puget Sound cities in all.