Ottawa Green Space and Tree Protection Rules for Builders

Before you break ground on a new build, addition, or major renovation in Ottawa, there's a layer of rules many builders overlook until it's too late: tree protection and green space requirements. Violating Ottawa's tree protection rules during construction can result in significant fines, and damaging a large tree on your lot can cost more to remedy than the fine itself.

Ottawa's Private Tree Protection By-law

Ottawa's Private Tree Protection By-law (No. 2009-200) protects large trees on private property across the city. Key provisions include:

• Protected tree threshold: Trees with a trunk diameter of 50 cm or more measured at 1.4 m above grade (DBH) are protected under the by-law
• Permit required to remove: You need a Tree Cutting Permit from the City before removing any protected tree
• Replacement requirement: If a protected tree is removed, replacement planting is typically required as a condition of the permit
• Injury during construction: Damaging a protected tree's root system during excavation can also trigger penalties, even if the tree itself is not removed

Trees on City-owned property (boulevard trees, park trees) are managed separately by Ottawa's Urban Forest Management branch and require approvals before any work is done near them.

Construction-Phase Tree Protection Zones

Even if your project doesn't involve removing any trees, construction activity can still damage protected trees through soil compaction from equipment, grade changes, chemical contamination, and physical damage to bark and branches.

Ottawa requires builders to establish Tree Protection Zones (TPZs) around protected trees before construction begins. A TPZ is typically defined as a fenced area with a radius based on the tree's trunk diameter, approximately 1 m of protection for every 2.5 cm of trunk diameter, with a minimum of 2 m. Physical fencing must be installed before any equipment or materials arrive on site.

No grading, digging, material storage, or vehicle parking is permitted within the TPZ without written approval from the City's Urban Forestry branch. Violations can result in stop-work orders.

Lot Coverage Limits

Beyond tree protection, Ottawa's Zoning By-law limits how much of your lot can be covered by buildings and structures. Lot coverage rules exist in every residential zone and serve to preserve neighbourhood character and ensure permeable surface remains on each lot for stormwater absorption.

Lot coverage maximums vary by zone and housing type, check your specific zone for the exact limit. Accessory structures (garages, sheds, garden suites) count toward the total lot coverage calculation. If you're planning a garden suite on a lot that already has a sizeable home, lot coverage is often the binding constraint. See: Ottawa Backyard Suite Setback Rules by Zone.

Front Yard Soft Landscaping Requirements

Ottawa's Zoning By-law requires a minimum amount of soft landscaping (grass, plants, trees, garden beds) in the front yard to prevent homeowners from paving over entire front yards for additional parking. For most residential zones, a minimum of 40% of the front yard must remain as soft (permeable) landscaping. This applies to both new construction and modifications to existing properties.

Boulevard Tree Restrictions

If your property is adjacent to a boulevard tree (a tree in the public right-of-way), you cannot remove, prune, or alter the grade within its root zone without City approval. If your construction project requires work near a boulevard tree, contact Ottawa's Urban Forestry branch early in the planning process, before your building permit is issued.

What Happens If You Violate Ottawa's Tree Protection Rules?

Damaging or destroying a protected tree without proper permits can result in fines under the Private Tree Protection By-law, stop-work orders, required remediation (replacement planting) at your expense, and civil liability if a damaged tree subsequently fails and causes property damage.

Frequently Asked Questions

Do I need a permit to cut down a tree in Ottawa?

Yes, if the tree has a diameter of 50 cm or more at 1.4 m above grade on private property. Boulevard trees require City approval regardless of size. Full details: Ottawa Private Tree Protection By-law.

What is a Tree Protection Zone in Ottawa construction?

A Tree Protection Zone (TPZ) is a fenced exclusion area around a protected tree that must remain undisturbed during construction. Its radius is based on the tree's trunk diameter. No equipment, materials, grading, or vehicle traffic is permitted within the TPZ without City authorization.

How much of my Ottawa lot can be covered by buildings?

Lot coverage maximums vary by zone and housing type. Check your specific zone designation in the Zoning By-law for the exact limit. Accessory structures count toward the total coverage calculation.

Can I pave my entire front yard in Ottawa?

No. Ottawa requires a minimum of 40% of the front yard to remain as soft landscaping to manage stormwater runoff and maintain neighbourhood green space character.

Who do I contact about trees near my Ottawa construction project?

Contact Ottawa's Urban Forestry branch for boulevard trees and TPZ requirements. For private tree permits, submit an application through the City's Development Applications portal.