Not every worrying-looking tree needs a formal report. A big maple that drops the odd dead branch in a windstorm doesn’t need one just because a neighbour mentioned it looks “a bit much” this year. A dead tree over a shared driveway, a lean that’s gotten worse since spring, or a letter from your insurer asking about a specific tree are different situations, and they do. The difference comes down to what happens if you’re wrong, and whether anyone besides you needs convincing.
You Need One When Something Else Is Riding on the Answer
A tree risk assessment is worth paying for when the outcome has to hold up to someone other than you: a neighbour who disagrees, an insurer deciding a claim, a city reviewing a permit, or a court. If the only question is “should I have this pruned,” you don’t need a formal report to answer it.
Three situations push a tree from “keep an eye on it” into “get it assessed”:
- A boundary or neighbour dispute where the other side doesn’t accept your read on the tree’s condition.
- A fallen tree, or one you’re worried will fall, where an insurance claim is involved or expected.
- A dead, dying, or hazardous tree in a municipality where the removal permit process asks for documentation of that condition.
A Neighbour Dispute Needs a Documented, Independent Finding
If a shared or boundary tree is in dispute and the other owner won’t agree it’s a problem, your opinion and theirs cancel each other out. An independent assessment on record moves the situation.
Freedman v Cooper, a 2015 Ontario Superior Court case (2015 ONSC 1373), involved a boundary maple that had already lost a third of its canopy in an ice storm. Two separate arborists documented the continuing risk. The co-owner who objected to removal still wouldn’t consent, and the court applied nuisance law over the Forestry Act’s consent requirement, ordering that owner not to interfere.
In Murphy v. Mullen (2021 ONCA 872), the Court of Appeal upheld $213,471.27 in damages for trespass after a neighbour cut and removed a tree line, about half of it on his own land, from the adjoining farm. It is a trespass case, not a boundary-tree ownership case, but it shows the scale. A documented hazard finding carries more weight than a claim either neighbour asserts. Our guide to neighbour tree disputes in Ontario covers the legal framework these cases sit inside.
An Insurance Letter or a Fallen Tree Changes the Calculation Too
Home insurance generally covers the cost of damage and debris removal when a tree falls, according to the Insurance Bureau of Canada. The exception is a tree that had been dead for a while with nothing done about it. That is negligence, and an insurer may try to recover the cost from you instead of paying the claim.
The IBC’s own prevention advice closes that gap directly: have a qualified professional regularly inspect your trees, especially if they show signs of damage or illness, and remove the ones that pose a risk. A dated assessment puts that inspection on paper. If the tree was rated healthy and fails in a storm that took out other trees nearby, the record shows an unpredictable event. If a problem was flagged and nothing was done, the insurer conversation changes, but it rests on what was known and when.
As Rates.ca reported, IBC’s Rob de Pruis put it plainly: “Just because you own a tree doesn’t mean that you’re legally liable for damages that it could have caused.”
Dead and Hazardous Tree Rules Differ by City
If a dead or hazardous tree is the reason you’re removing it, the exemption from the standard permit process depends on the municipality.
Toronto’s Chapter 813 exempts a 100%-dead tree from needing a full permit, but the city’s permit exception confirmation has to be in hand before removal, unless the tree is an immediate hazard, in which case it can come down first and get documented after. Vaughan’s By-law 177-2025 has no dead-tree exemption, so the permit itself is still required. The City’s Dead, Hazardous or Emerald Ash Borer-Infected Tree Permit needs no arborist report and has no fee. East Gwillimbury’s By-law 2024-077 is the most permissive of this group: dead, dying, or hazardous trees are exempt outright, and the whole bylaw carries no application fee at all.
Newmarket’s By-law 2022-10 splits the same category three ways: a dead or dying tree needs a permit but no report, a hazardous tree needs a report with no fee and no replacement planting, and a genuine emergency needs only an email and photos, no permit at all. Significant and Heritage Trees are never exempt, no matter the condition. Oakville’s By-law 2017-038 waives the application fee, not the application itself, for a dead tree (confirmed by the town or a certified arborist), a high-risk tree, an ash tree hit by emerald ash borer, or invasive buckthorn.
Our self-triage guide for assessing tree risk lists the visible signs to check. Our post on getting a dead tree documented before storm season explains why to do it before the first real windstorm.
What an Assessment Actually Involves
The formal version of this is TRAQ, the Tree Risk Assessment Qualification, a training and testing program the International Society of Arboriculture administers for arborists who already hold an ISA credential (or equivalent). It’s a two-day in-person course plus a half-day exam, renewed by retraining and retesting every seven years.
ANSI A300 (Part 9), the tree risk assessment standard, sets out three levels of inspection. A limited visual assessment is done from one specified perspective, like a foot or vehicle patrol past the property. The next level up is a 360-degree, ground-based visual inspection of the crown, trunk, trunk flare, above-ground roots, and site conditions, evaluated against whatever the tree could hit if it failed. Beyond that, arborists move to techniques like drilling, increment boring, pull testing, or radiation assessment, used when the ground-based inspection alone can’t pin down how far a problem extends.
TRAQ combines the likelihood the tree fails, the likelihood something gets struck if it does, and the consequences if it did, into one rating: low, moderate, high, or extreme.
What Drives the Cost
There is no fixed price for a tree risk assessment. The number of trees, the access and complexity of the site, how the report will be used, and how urgently you need it all move the cost. A report headed to a lawyer or an insurer takes more documentation than one for your own records, and a same-week assessment ahead of a storm costs more than one on a normal schedule.
Getting the Right Read Before You Need It
If a neighbour, an insurer, or a city permit office is going to be looking at your tree’s condition, get the assessment done before that conversation starts, not in the middle of it. A tree risk assessment from our ISA Certified consulting arborists follows the TRAQ methodology and gives you a documented rating you can hand to whichever party is asking. Contact us with a description of the tree and what’s prompting the question, and we’ll tell you whether you need one before you book a site visit.