You’ve probably searched “tree service near me,” gotten a handful of results, and noticed that almost every company calls themselves arborists. Some have it right in their name. Some have it on their truck. But here’s the thing most homeowners don’t know: “arborist” isn’t a protected title. There’s no law that says you have to earn it. Anyone can use it.
That gap matters — especially in Oakland County, where the trees on your property are older, larger, and more valuable than most people realize. The red oaks in Bloomfield Hills, the maples in West Bloomfield, the ash trees in Farmington Hills — these aren’t young trees. They’re 50, 60, sometimes 70 years old. This post explains what ISA certification actually requires, what it means for the work being done on your trees, and what questions to ask before you let anyone near them.
What Is a Certified Arborist, Really?
ISA Certified Arborist is a credential issued by the International Society of Arboriculture, a worldwide nonprofit focused on professional tree care. To earn it, a candidate needs at least three years of full-time, hands-on arboricultural experience — or a relevant degree from an accredited institution. Then they have to pass a 200-question exam covering tree biology, pruning technique, disease diagnosis, root systems, risk assessment, climbing safety, and more. The minimum passing score is 76 out of 100.
That’s not a weekend course. It’s a genuine knowledge threshold. And because the certification expires every three years, certified arborists have to earn 30 continuing education units just to keep it — which means they stay current as the science evolves.
The ISA credential is accredited by the American National Standards Institute, the same body that accredits professional certifications in medicine, engineering, and law. That context matters when you’re deciding who you trust to work on a 70-foot red oak in your backyard.
What Does a Certified Arborist Know That Others Don’t?
The practical difference between a certified arborist and an uncertified tree worker shows up in ways that aren’t always visible from the street — but matter enormously over time.
Take pruning cuts. A certified arborist knows exactly where to make a cut to minimize wound size and support the tree’s natural defense response. An improper cut — one made too close to the trunk, or leaving a stub — creates an entry point for decay fungi and insects. The tree might look fine for a season or two. Then it doesn’t.
The same applies to timing. In Oakland County, oak trees are everywhere — on residential lots in Bloomfield Hills, West Bloomfield, Farmington Hills, and throughout the region. Oak trees have a specific pruning window. Certified arborists know not to prune oaks when temperatures have been above 50°F, because bark beetles are active in warm weather and are attracted to fresh pruning cuts. Those beetles can carry oak wilt spores directly into an open wound. Oak wilt can then spread to neighboring trees through root grafts and kill an entire stand. An uncertified crew trimming your oaks in June doesn’t know this — or doesn’t care.
There’s also the question of what to do with a tree that’s struggling. A certified arborist can distinguish between a tree that needs treatment and one that needs to come down. That distinction matters when you’re emotionally attached to a tree that’s been in your yard for 40 years, and it matters financially when a removal costs significantly more than a targeted intervention. The honest assessment is the one you want — and certification is part of what makes that possible.
Beyond individual tree health, certified arborists are trained in formal risk assessment. A tree can look perfectly healthy from the outside while harboring internal decay, root damage, or structural weakness that makes it a genuine hazard. The training to identify those hidden failure points — and to communicate the risk clearly to a homeowner — is something that takes years of study and field experience to develop.
How to Verify If an Arborist Is Actually ISA Certified
This is simpler than most people realize, and it’s worth doing. The ISA maintains a public credential directory online where you can search by name or location to confirm whether someone’s certification is active. If a company claims to have certified arborists on staff, you can verify it in about 30 seconds. If they can’t give you a name to look up, that’s information too.
Beyond certification, ask for proof of insurance — specifically general liability and workers’ compensation. This isn’t a formality. If an uninsured worker is injured on your property, you as the homeowner can be held financially responsible. That’s a real legal exposure, not a hypothetical. Consumer protection resources from NC State Extension, the BBB, and state forestry agencies all flag this as one of the most important things to verify before any tree work begins. Don’t just accept a certificate of insurance — call the insurer directly to confirm the policy is active.
You should also ask whether the company holds any Michigan licenses or municipal registrations. Legitimate tree care companies operating in Oakland County carry the required state and local credentials on top of their ISA certification. If a company can’t clearly answer questions about their licensing, that’s a red flag worth taking seriously.
One more thing to watch for: if someone recommends “topping” your tree — cutting back the main trunk or large scaffold branches to reduce height — walk away. Tree topping is widely condemned by certified arborists because it creates weak, fast-growing regrowth, exposes the tree to disease, and often results in removal within a few years anyway. A certified arborist will never recommend it as a standard practice. If that’s the first suggestion you hear, it tells you something about the level of training behind it.
Arbor Tree Care in Oakland County: Why Local Knowledge Changes Everything
Oakland County’s tree canopy isn’t generic. The county’s inventoried tree population has been appraised at $50 million — and that figure reflects a landscape dominated by mature, high-value species: red oaks, white oaks, sugar maples, silver maples, and ash trees that have been growing on residential lots since the 1960s and ’70s.
Those trees are assets. They’re also aging. A 60-year-old red oak behaves very differently — and fails very differently — than a young tree. The expertise required to assess, maintain, and safely work on mature trees in a dense suburban landscape like Oakland County is not the same as general landscaping knowledge. It’s specific, it’s earned, and it matters.
Oakland County Tree Threats Every Homeowner Should Know About
Two issues in particular define the current tree health landscape across Oakland County, and both require certified expertise to handle correctly.
The first is oak wilt. Oakland County’s residential neighborhoods — from Milford and Farmington Hills to Rochester Hills and West Bloomfield — are full of red and white oaks. Oak wilt is a fungal disease that moves fast, spreads through root grafts between neighboring trees, and can kill an infected red oak within a single growing season. The primary prevention is simple in concept but critical in execution: don’t prune oaks during warm weather. A certified arborist knows this. They also know how to identify early signs of infection, how to assess whether a tree is still treatable, and how to prevent the disease from spreading to adjacent trees on your property or your neighbor’s.
The second is Emerald Ash Borer. Michigan was the first state in North America where EAB was detected — in the Detroit metro area in 2002 — and Oakland County’s ash tree population has been heavily impacted over the past two decades. Many of those trees are now dead or structurally compromised, which makes them hazardous to remove. A large, brittle ash tree near a structure or a power line is not a job for an uncertified crew. It requires a trained eye for structural failure points and the technical skill to bring it down safely.
Both of these threats are ongoing. They’re not historical problems — they’re active ones, and they require the kind of ongoing education that ISA certification is specifically designed to maintain. That 30-unit continuing education requirement every three years isn’t bureaucratic overhead. It’s how certified arborists stay current on exactly these kinds of evolving threats.
What to Expect From a Certified Arborist Tree Service — Before, During, and After
The experience of hiring a certified arborist tree service should feel different from the moment you make the first call. A legitimate operation will send someone out to assess your trees in person before quoting — no drive-by estimates, no phone quotes based on a photo. The person doing the assessment should be able to explain what they’re seeing, answer your questions directly, and give you an honest recommendation that isn’t automatically a pitch for the most expensive option.
During the work itself, a certified crew knows how to protect the surrounding property. That means not using climbing spikes on living trees — spikes damage the cambium layer and should only be used on trees being removed. It means making cuts at the right location and angle. It means being aware of what’s below, beside, and above the tree before a single branch comes down. In Oakland County’s suburban landscape, that often includes fences, landscaping, structures, and utility lines. Working near energized power lines is a separate category entirely — it requires line-clearance certification, specialized training, and specific insurance. Most general tree companies are not qualified for this work, which leaves a lot of homeowners in a bind when the tree they need removed is growing into a DTE line.
After the job, cleanup is part of the service — not an afterthought or an upsell. Debris hauled away, lawn left in the same condition it was found, and clear communication throughout the process including any weather-related rescheduling. That’s what a professional operation looks like, and it’s a reasonable standard to hold any company to before you hire them.
We’re Ivan’s Tree Services LLC, and we hold our work to exactly that standard. Our arborists are ISA certified and line-clearance certified, meeting or exceeding DTE and Consumers Energy requirements. Ivan is personally on-site for every job — not an estimator who hands off to a different crew. We carry full general liability, workers’ compensation, and all required Michigan licenses and municipal registrations. And if something comes up — a storm, an emergency, a question at 10pm — someone answers the phone.
How to Choose the Right Certified Arborist in Oakland County
The short version: ask for the ISA certification and verify it. Ask for proof of workers’ compensation and general liability insurance, and call the insurer to confirm. Ask whether the person quoting the job will be on-site when the work happens. Ask what cleanup looks like. These aren’t unreasonable questions — they’re the baseline for hiring anyone to work on mature trees on a property you care about.
Oakland County’s trees are older, larger, and more complex than most homeowners fully appreciate until something goes wrong. The good news is that finding a genuinely qualified tree care arborist isn’t hard if you know what to look for — and now you do.
If you have trees you’re uncertain about, or you’ve been putting off getting an honest assessment, Ivan’s Tree Services LLC offers free on-site estimates with no obligation. We serve homeowners across Oakland County and the surrounding area, and we’re happy to take a look and tell you exactly what we see.