Most tree companies sell labor: a crew, a truck and a chipper. What an arborist sells is the judgment that comes before any of that - whether a tree is actually failing or just looks alarming, what is causing a decline, what the realistic options are, and whether the work somebody has quoted you is the right work at all.
Michael Calabro is an ISA Certified Arborist, certificate FL-362432A, and he is the person who looks at your trees and writes your estimate. If you want to check that yourself, the International Society of Arboriculture keeps a public registry of certificate holders and the number above will return the record.
What the certification actually required
"Certified" on its own tells a homeowner nothing, so here is what this particular certification involved.
The ISA Certified Arborist credential requires documented full-time experience in arboriculture before you are allowed to sit for it, and then an exam covering tree biology, identification, soil and water management, pruning practice, diagnosis and treatment, planting and establishment, risk assessment, tree protection and safety. It is not a weekend course, and it is not a membership you can buy.
It also has to be maintained. Holding it means earning continuing education credits on a recurring cycle; let those lapse and the certification lapses with them. And it is issued to the person, not to the business - which is exactly why it matters who shows up to look at your tree rather than whose logo is on the truck.
Michael also appears on the Florida Department of Environmental Protection's Professional Mangrove Trimmers list, which is a separate state credential and a legal requirement for most mangrove work in Florida.
When you want an arborist rather than a crew
Some jobs are simply labor, and there is nothing wrong with that. A dead pine over the driveway does not need a diagnosis; it needs a rope and a chipper. These are the situations where the judgment is the job:
- A tree is declining and nobody has said why. Thinning canopy, early leaf drop, dieback at the tips, mushrooms at the base. The visible symptom is rarely where the problem is.
- You have a removal quote and it feels wrong. Sometimes the tree does have to come down. Sometimes it needs a cable, a root collar excavation, or nothing at all. A second opinion costs a fraction of a removal.
- You are buying a property with significant trees. Large trees are either an asset or a liability and the difference is not obvious from the curb.
- You are building, paving or trenching near trees. Most construction damage is invisible for two or three years and irreversible by the time it shows.
- A storm has been through and you need a judgment, not a panic. Some damaged trees recover well. Others are done and should come down before the next system.
- Somebody has asked you for it in writing. An HOA, an insurer, a permitting office or a neighbor dispute usually wants an assessment from a certified arborist on paper.
What an assessment actually looks at
An honest assessment starts at the ground and works up, because most of what kills a mature tree happens below eye level.
We look at the root collar first - whether the flare is visible or buried, whether the tree was planted too deep, whether mulch or fill has been piled against the trunk, and whether there is girdling root strangling the stem. Buried collars are one of the most common causes of slow decline in Florida landscapes and one of the most fixable.
Then the trunk and the unions: cavities, cracks, included bark where two stems meet at a tight angle, decay fungi, old topping wounds and the weak regrowth they produce. A codominant union with included bark is a structural problem whether or not the tree looks healthy.
Then the canopy: dieback pattern, density, deadwood load, previous pruning cuts and whether they were made correctly, and how the weight is distributed out on the limbs.
Then the site: grade changes, compaction, drainage, irrigation, salt exposure, what has been built or dug nearby, and what is underneath the tree if part of it fails. That last one matters more than anything else on the list. Risk is not just how likely a failure is; it is what the failure would land on.
How far the assessment goes: the three levels
Start with what the estimate is, because the words matter here. When you call about a tree, we come out, look at it and tell you what we think and what the work would cost. That visit is free, and it is a quote with an informed opinion attached rather than a formal assessment. For most jobs it is all you need, and we will tell you when that is the case.
When you need more than an opinion, tree risk assessment has three defined levels. They are not marketing tiers we invented; they come from the ISA best-practice guidance that accompanies the ANSI A300 tree risk assessment standard, and the words mean particular things, so it is worth knowing which one you are being sold.
Level 1, limited visual. A fast look from a defined perspective, usually across many trees rather than one: walking or driving a property, flagging obvious defects and identifying which trees need a closer look. This suits an HOA, an acreage or a commercial site that wants to know where its problems are before spending money tree by tree.
Level 2, basic assessment. The one most people actually want for a specific tree, and a documented piece of work. A 360-degree inspection from the ground covering the root collar, trunk, unions and crown, along with the site and what sits within reach of a failure. It is written up: species, diameter, height, condition, the defects found, likelihood of failure, what is in the impact zone, a risk rating and the recommended mitigation. This is normally the document an insurer, an HOA or a permit office is asking for.
Level 3, advanced assessment. Everything in a Level 2, plus specialist work for cases where the view from the ground is not enough. That can mean aerial inspection by lift or drone, and instrument testing such as a resistograph, which drives a fine needle into the trunk and records the resistance as it travels, mapping sound wood against decay inside a trunk you cannot see into.
Level 3 is not routine and most trees never need it. It earns its cost on the tree where the stakes justify it: a heritage tree, a specimen a municipality wants documented before it will approve a permit, or a large tree standing over something that cannot be moved out of the way.
What it costs, and what comes back. The estimate visit is free. Levels 2 and 3 are paid work and we price them before we start, so nothing about the bill is a surprise. If you go ahead with the mitigation the assessment recommends, part of what you paid for the assessment comes off the price of that work.
Preserving trees through construction
The most avoidable tree loss we see comes from building work, and it almost never gets blamed on the building work because the tree does not die for another two or three years.
Roots do not go deep in Florida sand; they go wide, mostly in the top eighteen inches, and they extend well past the drip line. Trenching a service line across that zone, scraping the grade, or running loaded equipment over it repeatedly does damage that no amount of watering afterwards will undo.
If you are planning work near trees you intend to keep, the useful time to involve an arborist is before the equipment arrives: establishing a protection zone, routing trenches, deciding what genuinely can be kept and being honest about what cannot. Where roots have already been buried or compacted, root care and air spading can excavate and correct without cutting what is left.
Pruning is a standard, not a preference
Pruning is the service most often done badly, and badly here is not a matter of taste - there is a written standard.
We work to ANSI A300, the American national standard for tree care operations, and to ANSI Z133 for safety. In practice that means named, specific operations: crown cleaning, crown raising for clearance, crown reduction where reduction is genuinely appropriate, and structural pruning to build a sound branch architecture while the tree is still young enough for it to matter.
It also means limits. There is a defensible amount of live tissue to remove in one season and an indefensible amount, and "while you are up there" is how a healthy tree gets pushed into decline.
Two things we will not do: topping, which leaves stubs, invites decay and forces weak regrowth that fails more readily than what it replaced; and lion-tailing, which strips the interior of a limb so every bit of weight ends up at the tip. Both look like work has been done. Both make the tree more dangerous than before.
The pruning work itself lives on our trimming and pruning page, including structural pruning and young-tree training. This page is about the assessment that decides what should be cut in the first place.
When the answer is not removal
An arborist who recommends removal every time is not assessing anything. Trees with structural defects are often better served by cabling and bracing than by a chainsaw, a declining tree may be responding to a buried collar or a compacted root zone rather than dying, and a tree that is genuinely too close to a structure sometimes only needs the clearance pruning it has never had.
Removal is the right call often enough. It is simply not the only call, and you are entitled to know which one you are getting and why.
How to check that an arborist is actually certified
"Arborist" is not a protected word. Anyone can put it on a truck or a website, and Florida has no state arborist license to fall back on, so the title by itself tells you nothing. What is protected is the credential.
ISA Certified Arborist is a registered certification mark belonging to the International Society of Arboriculture, and ISA limits its use to people who have met the experience requirement, passed the certification exam, and remain in good standing. Three things follow from that, and they are worth two minutes before you let anyone quote you.
A certification belongs to a person, never to a company. ISA grants it to an individual, and its trademark policy says permission to use the mark "may not be transferred to, assigned to, or otherwise used by, any other individual, organization, business, or entity". So no tree company is itself a certified arborist. If a business implies the company holds the credential, the fair question is simply: which person holds it, and will they be the one looking at my tree?
Proper use shows a name and a number. ISA requires the mark to appear with the holder's full name and certification ID. A certification badge sitting on a website with no name attached and no number under it is not proper use of the mark, whatever else is going on.
You can check it yourself. ISA runs a public credential directory, and any certified arborist can give you their number to look up. Ours is Michael Calabro, certificate FL-362432A. Worth knowing: listing in the directory is voluntary, so someone not appearing there is not proof of anything on its own - ask them to show you the certificate instead.
None of this means an uncertified company is a bad tree company. There are excellent climbers and crews in this region with no letters after their name, and a certificate is no substitute for insurance, experience or references you can call. The point is narrower than that: certification is a specific, checkable claim, and a specific claim that turns out to be false tells you something useful about who you are dealing with, before they are up a tree over your roof.
If you want to check ours before you call, please do. That is rather the point of having it.
Where we work
We are based in North Port and work across Sarasota and Charlotte County, including Venice, Sarasota, Nokomis, Osprey, North Port, Englewood and the surrounding communities. The full list is on our service area page.
If you have a tree you are unsure about, tell us what you are seeing and we will take a look.
Questions about ISA Certified Arborist
What is an ISA Certified Arborist, and why does it matter?
It is a credential from the International Society of Arboriculture, earned by documented experience plus an exam covering tree biology, diagnosis, pruning practice, risk assessment and safety, and maintained with ongoing continuing education. It matters because it is issued to a person rather than a company: the certificate tells you the individual assessing your tree has been examined on the subject.
How can I verify the certification?
Michael Calabro holds certificate FL-362432A. The International Society of Arboriculture publishes a searchable registry of current certificate holders, so you can confirm it independently rather than taking our word for it. We would encourage you to check any tree company that claims it.
Do I need an assessment, or can I just get a quote?
If you already know what you want done and the tree is straightforward, a quote is enough and that is what we will give you. An assessment earns its keep when something is wrong and nobody has explained why, when a removal has been recommended and you want a second opinion, or when you need the findings in writing for an HOA, an insurer or a permit.
My tree looks sick. Can you tell me what is wrong with it?
Often, yes, and the cause is frequently at the root collar rather than in the canopy where the symptom shows. Buried root flares, girdling roots, compaction and grade changes account for a great deal of slow decline in Florida landscapes. Some conditions are not treatable, and where that is the case we will say so plainly rather than sell you a program that will not change the outcome.
Another company told me my tree needs to come down. Should I get a second opinion?
It is usually worth it. Removal is sometimes exactly right, and when it is we will tell you so. But cabling, root collar excavation or overdue clearance pruning solve some of the problems that get quoted as removals, and the cost of a second look is small next to the cost of taking down a mature tree that did not need to go.
Why will you not top a tree, even if I ask?
Topping removes the leaders and leaves stubs, which invites decay and forces a flush of weakly attached regrowth. The tree ends up more likely to fail than before, and the problem returns larger in a few years. It also falls outside the ANSI A300 standard we work to. If a tree is genuinely too large for its space, the honest options are a proper reduction where the species tolerates it, or removal.
We are building near some trees we want to keep. When should we call?
Before the equipment arrives. Most construction damage happens to roots in the top eighteen inches of soil, well outside the drip line, and it typically does not show in the canopy for two or three years, by which point it cannot be undone. Setting a protection zone and routing trenches beforehand costs very little compared with losing mature trees afterwards.
Do you handle mangroves?
Yes. Mangrove trimming in Florida is regulated by the state, and Michael appears on the Florida Department of Environmental Protection Professional Mangrove Trimmers list, which most mangrove work legally requires. See our mangrove trimming page for what is and is not permitted.
Is it illegal for a company to call itself an arborist?
No. "Arborist" is a general job title, not a protected one, and Florida has no state arborist license, so anyone may use the word. What is restricted is the ISA credential: "ISA Certified Arborist" is a registered certification mark and ISA limits it to individuals who passed the exam and remain in good standing. So the word itself means little; the certificate is the checkable part.
Can a whole company be a certified arborist?
No. ISA grants certification to a person, and its trademark policy states the permission cannot be transferred to or used by any organization or business. A company can employ a certified arborist, which is a different and perfectly honest claim. If a business presents the credential as the company's own, ask which individual holds it and whether that person will be the one assessing your trees.
Which level of assessment do I actually need?
Most people need none of them. If you want a price for work you already know you want, the estimate visit is free and that is the end of it. Ask for a Level 2 when something needs explaining or documenting: an unexplained decline, a second opinion on a removal, or a report an insurer, HOA or permit office has asked for. Level 3 is for the rare tree where the ground-level picture is not enough and the stakes justify instrument testing.
Is the assessment fee wasted if I go ahead with the work?
No. If you proceed with the mitigation the assessment recommends, part of what you paid for the assessment is credited against the cost of that work. The estimate visit itself is free either way.
What is a resistograph?
A diagnostic tool used in a Level 3 assessment. It drives a very fine needle into the trunk and records the resistance as it travels, which maps sound wood against decay inside a trunk nobody can see into from the outside. It is minimally invasive, and it is used when a tree matters enough to justify knowing what is actually inside it rather than estimating.
Need ISA Certified Arborist?
Tell us what you're looking at and we'll come take a look - free, with a firm written price and a straight recommendation.