Resources
What Is an Arborist Report?
The document that stands between you and a tree permit, explained: what it is, what has to be in it, and who is qualified to write one.
Quick Answer
An arborist report is a written, signed document that identifies the trees on or near a property, records their species and condition, and states a specific finding, most often supporting a request to remove a tree or to build near one. GTA municipalities generally require the report to be prepared by an ISA Certified Arborist, and it must be submitted with your permit application, not after the fact.
What Goes Into the Report
A properly prepared arborist report is not a letter or a one-page opinion. At minimum it includes a tree inventory (species, trunk diameter at breast height, height, crown spread, and a condition rating), a scaled site plan showing where each assessed tree sits, photographic documentation, and a written recommendation that ties back to the applicable municipal bylaw.
For a tree removal application, that recommendation explains why removal is warranted and usually includes a replanting plan, since most municipalities require replacement trees as a condition of approval. For a construction project, the report expands to cover every tree the work could affect, not just the one on the applicant's own lot, and adds a tree protection plan with calculated protection zones. Our arborist report cost guide breaks down exactly what is included at each price point.
Who Can Write One
Municipal reviewers expect the report to come from a credentialed professional, typically an ISA (International Society of Arboriculture) Certified Arborist. The certification number should be verifiable, and the report should be signed by the certified individual, not simply produced by a company that employs one.
Who prepares the report also matters beyond the credential. A firm that also performs tree removal has a financial incentive to recommend it. A consulting-only firm has no removal contract to sell, so municipalities and property owners alike tend to view those assessments as more objective. See independent arborist vs. tree removal company for the full comparison.
When Municipalities Require One
Most GTA municipalities require an arborist report before approving the removal of a protected tree, and before issuing a building or development permit for work that falls within a protected tree's root zone. Requirements vary by city: the trunk diameter that triggers protection ranges from 15 cm to 30 cm depending on the municipality, and some cities require additional documentation for ravine or natural feature areas. Our municipal bylaw guide covers the thresholds for nine GTA cities.
The trigger for a construction project is proximity, not intent to remove. An addition or excavation that never touches a tree can still require a report if it disturbs the root zone.
The Different Types
"Arborist report" is a category, not a single document. The specific type your project needs depends on what you are asking the municipality to approve.
- Tree Removal Report
- Supports a permit application to remove one specific protected tree. Covers up to a small number of trees per report.
- Construction Arborist Report
- Covers every tree a development or building project could affect. Includes a full inventory and a tree protection plan, submitted with the building permit application.
- Tree Information Report
- A lighter-weight documentation of tree species, size, and condition, used where a municipality asks for tree data without a removal or construction decision attached.
If you are not sure which of these applies to your project, or whether you need a site inspection instead, two resources walk through it in detail: which arborist report do I need matches situations to the right document, and report vs. inspection explains the difference between the report you submit before work starts and the inspection that verifies compliance during construction.
How Long a Report Stays Valid
Most arborist reports are treated as valid for 12 months from the site inspection date, not the date printed on the cover page. A change in the tree's condition, construction activity near the root zone since the inspection, or a revised project scope can make a report outdated before that window closes.
What It Costs
Pricing depends on report type, tree count, and municipality. Rather than restate numbers here that can drift, see our current pricing breakdown for every report type we offer.
Frequently Asked Questions
- What is an arborist report?
- An arborist report is a written document, prepared and signed by a qualified arborist, that identifies the trees on or near a property, assesses their condition, and supports a specific request: a permit to remove a tree, a construction project near protected roots, or clearance after a stop work order. Most GTA municipalities will not process a related permit application without one.
- What does an arborist report contain?
- A standard report includes a tree inventory with species, trunk diameter, and condition ratings, a site plan showing tree locations, photographs, a written recommendation tied to the applicable bylaw, and, for construction projects, a tree protection plan with calculated protection zones. Missing components are the most common reason a municipality sends a report back for revision.
- Who can write an arborist report?
- In Ontario, municipalities generally require the report to be prepared by an ISA (International Society of Arboriculture) Certified Arborist, or an equivalent qualified professional such as a registered consulting arborist. A report from someone without recognized credentials is routinely rejected at the application stage.
- How much does an arborist report cost?
- Cost depends on the report type. Tree removal reports and construction reports are priced differently because they cover different scope. See our current pricing guide for exact starting prices by report type.
Related Resources
Which Arborist Report Do I Need?
Match your situation to the right report type.
Read the guide →Arborist Report vs. Site Inspection
Two different documents for two different points in a project.
Read the guide →How Much Does an Arborist Report Cost?
Current pricing for every report type in Toronto and the GTA.
Read the guide →Independent Arborist vs. Tree Removal Company
Why the source of your report matters for permit approval.
Read the guide →Request a quote
Tell us about your property and an ISA Certified Arborist will follow up with next steps and a firm quote.
- Free consultation, same-day response.
- Municipal-ready report delivered in 2 business days.
- Independent assessment. No tree-removal sales, no conflict of interest.
Serving Toronto, the GTA, and across Southern Ontario.
ISA Certified Arborist · ISA Member · ISA Ontario Member · ASCA Member