Blog · Cambridge

Cambridge's private tree by-law 23-105: when you need a permit, the 20 cm rule and the exemptions

In Cambridge you need a permit to remove, cut down or injure any tree on private property that measures 20 cm (8 inches) or more in diameter at about 1.4 metres above the ground, on any size of lot. That has been the rule since Private Tree Preservation By-law 23-105 came into force on January 1, 2024. Dead trees, imminent hazards, storm emergencies and routine pruning have their own routes, but none of them is simply picking up a saw.

Last updated October 24, 2026 · Reviewed by the Cambridge Tree Removal team

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

If the trunk is 20 cm or more in diameter at breast height, yes. The City of Cambridge's Private Tree Preservation By-law 23-105 was passed on November 28, 2023 and came into force on January 1, 2024. It applies city-wide, in Galt, Preston, Hespeler and Blair alike, and it regulates trees on private property regardless of how big the lot is. That is the main difference from Kitchener, where the private tree by-law only reaches lots over one acre, and from Waterloo, which has no private tree by-law at all. A tree under 20 cm needs nothing. A healthy maple in a Preston back yard that is over the threshold needs a permit before anyone cuts it, and the by-law counts injuring the tree, including regrading or compacting inside the drip line, in the same way as destroying it.

How to measure 20 cm DBH

DBH is diameter at breast height. The City's forestry page says the measurement is taken at 1.4 metres above the ground; the by-law text itself defines it at 1.37 metres, which is the same height for practical purposes. Wrap a tape around the trunk at that height, read the circumference, and divide by 3.14 to get the diameter. A circumference of about 63 cm is a 20 cm tree. Where the trunk leans or the ground slopes, the by-law measures along the centre axis of the trunk from grade. For a multi-stemmed tree, the largest trunk is used. If the tree is close to 20 cm, have the arborist measure it; a 19 cm tree needs no permit and a 21 cm tree does.

What the permit application needs

For one to nine trees, the application goes to the City's forestry division and needs:

• An arborist assessment by a qualified tree professional giving the tree's location, species, DBH and condition.
• Clear photographs of the whole tree.
• The non-refundable application fee, which is on the City's forestry page and on our cost page.
• An Adjacent Property Owner Consent Form if the tree is a boundary tree. The by-law defines a boundary tree as one whose trunk straddles the line between properties, and section 7(3) requires written consent from all owners of the abutting property.

You may not start work until the permit is issued. Once it is, section 15 requires the permit to be posted in a visible spot on the property at least five days before the tree is injured or destroyed, and it has to stay up until the work is complete. The permit expires twelve months after it is issued. Removing ten or more trees over 20 cm is a different process entirely, a Site Alteration Permit through the City's engineering division, which is the route for lot clearing rather than a back-yard removal.

The exemptions: dead, hazardous, emergency and pruning

The by-law does not make you apply for a full permit to deal with a tree that is already dead or about to fall, but it does not let you decide that alone either. The City's forestry page sets out four exemption routes:

1. Dead tree. Email forestry@cambridge.ca before removal with a photo, the location, the species and the DBH. Once the City confirms, the tree can come down without a permit. The emerald ash borer has made this the busiest route in Cambridge; a borer-killed ash is still a private tree under the by-law and still goes through the dead-tree request, which is quick.
2. Imminent hazard. A split union over the house or a tree whose roots have lifted needs a detailed arborist report, photographs, location, species and DBH submitted to forestry@cambridge.ca before removal. A formal Tree Risk Assessment is preferred but not required. If the City does not accept the hazard exemption, the tree can still be removed through the standard permit.
3. Emergency. A tree on the roof after a storm can be dealt with immediately, but documentation has to reach forestry@cambridge.ca within 48 hours, and the City notes that compensation may apply if the emergency is not clearly shown. Photographs before cutting are what make that case.
4. Maintenance pruning. Pruning to good arboricultural practice, as determined by a qualified tree professional, is exempt. Topping is not maintenance pruning.

The by-law itself also lists work that is outside its scope, including trees classified as invasive, work done by or for the municipality, work by an electricity distributor on its lines, cutting under the Region's Woodland Conservation By-law, and work carried out by the Grand River Conservation Authority. The invasive exemption is the one homeowners ask about most; which species count is a question for the City's forestry staff, and the answer is not simply every Norway maple.

Replacement trees and posting the permit

A permit to remove a healthy tree comes with a condition: the canopy has to be replaced. The City's schedule sets one replacement tree for a tree of 20 to 30 cm DBH, two for 31 to 40 cm, three for 41 to 70 cm and four for anything over 70 cm. Replacement trees must be at least 20 mm in diameter in a 7-gallon or larger pot. Instead of planting, or in combination with it, the owner can pay a per-tree cash-in-lieu amount into the City's Replacement Tree Planting Reserve Fund; the current figures are on the City's forestry page. For a large old silver maple that genuinely needs to go, four replacement trees or the equivalent payment is often the largest part of the permit cost, which is a strong argument for looking at whether pruning and crown reduction can keep the tree before applying to remove it.

What this means for your quote

In Cambridge the permit is part of the job, and the contractor we book for Cambridge builds it into the schedule. On the site visit the tree is measured at 1.4 metres, its condition is assessed, and the route is chosen: dead-tree request, hazard submission, or full permit with arborist report and replacement plan. The quote says which route applies and how long it adds. A boundary tree waits for the neighbour's signed consent. Nothing is cut until the City has answered, and once the permit is issued it is posted on the property for the five days the by-law requires. Our tree removal and permits page explains the process step by step, and if you want to know which route your tree is likely to take, send a photo and the trunk circumference at chest height.

Sources

• Forestry (Private Tree By-law 23-105, exemptions, replacement schedule) - City of Cambridge
• Private Tree Preservation By-law 23-105 (full text) - City of Cambridge
• Tree protection (Kitchener's one-acre private tree rule) - City of Kitchener
• City Tree Bylaw 2014-078 (Waterloo, city trees only) - City of Waterloo