What Is a Tree Protection Zone?
A tree protection zone (TPZ) is the area around a tree that’s fenced off during construction to protect its roots, trunk and canopy. Here’s how it works in Ontario municipalities.
An area where nothing happens
Inside a tree protection zone, construction activity is restricted. Municipal standards commonly prohibit:
- Operating, parking, repairing or refuelling equipment or vehicles
- Storing materials or fill
- Grade changes, surface treatments and excavation
- Moving or removing the barrier without the municipality’s authorization
Examples from City of Burlington SS12A and Richmond Hill’s Tree Preservation By-law. Your municipality’s wording may differ.
Based on trunk diameter
Most municipalities set a minimum distance from the outside edge of the trunk, based on the trunk diameter at about 1.4 m above grade (DBH). The tables differ from City to City:
| Trunk diameter | Toronto | Mississauga | Oakville | Burlington | Vaughan | Richmond Hill |
|---|---|---|---|---|---|---|
| 25 cm | 1.8 m | 1.8 m | 2.4 m | 2.4 m | 1.8 m | 2.4 m |
| 35 cm | 2.4 m | 2.4 m | 3.0 m | 2.4 m | 2.4 m | 2.4 m |
| 45 cm | 3.0 m | 3.0 m | 3.0 m | 3.0 m | 3.0 m | 3.0 m |
Mississauga figures are for street trees. Hamilton’s standard details place hoarding beyond the drip line instead. Every municipality can require a larger zone.
Snow fence, plywood or horizontal
Framed snow fence
1.2 m orange web fencing on a 2×4 frame or T-bar posts. Burlington’s SS12A and Hamilton’s PK-1100 details use this approach.
Plywood hoarding
Solid plywood on a 2×4 frame. Toronto’s standard is 2.4 m (8′), and Markham’s is ¾” plywood at 1.22 m. Richmond Hill requires plywood where stockpiles or machinery are close.
Horizontal protection
Where traffic over roots can’t be avoided. Markham specifies wood mulch under two staggered layers of ¾” plywood, and Vaughan may require horizontal hoarding.
The rules around the fence
- Signs vary: Toronto requires 40 × 60 cm on all sides, Markham 46 × 61 cm, Burlington a minimum of 10″ × 14″, and Mississauga sells mandatory City signs.
- Inspection: many municipalities inspect the barrier before work starts. Markham’s Tree Preservation Technician inspects before any demolition or construction, and Vaughan charges inspection fees.
- Removal: most require authorization before the barrier comes down. Mississauga inspects all hoarding before removal.
- Neighbouring trees: Oakville and Vaughan include neighbouring trees within 6 m of the site.
See your municipality’s rules
Tree protection zone FAQ
Is a tree protection zone the same as the drip line?
Not usually. Most municipalities set a minimum distance based on trunk diameter. Hamilton’s standard details place hoarding beyond the drip line, and Toronto uses the greater of the drip line or the table distance in ravine areas.
Can I build tree protection fencing myself?
Yes, if it’s built to your municipality’s spec. The City pages on this site list the requirements with links to the official documents.
Who decides where the fence goes?
Your permit conditions or arborist’s Tree Protection Plan, based on the municipality’s minimum distances. The City can require a larger zone.
Do you build to the arborist report?
Yes. We build what the arborist report states: the protection zones, the barrier type and any extra measures it calls for. Where the report asks for more than the City minimum, we build to the report.
Can you recommend an arborist?
Yes. If your permit needs an arborist report or Tree Protection Plan and you don’t have one yet, tell us when you get in touch and we’ll recommend an arborist.
Need tree protection installed?
Send us your permit conditions, site plan or arborist’s Tree Protection Plan and we’ll quote it to your municipality’s spec.