Canada-wide tree rule guide
Pruning & tree injury
Tree bylaws may regulate more than felling. Excessive crown removal, topping, root cutting or damage from excavation can be defined as injury.
What to check.
Check the local definition of pruning and injury before major work. Normal maintenance can be exempt while aggressive pruning is not.
Why there is no national yes/no answer.
Canadian municipalities use very different systems. Some regulate most larger private trees. Some regulate only woodlots, environmental lands or development sites. Others focus almost entirely on public trees. The city guide is where Tree Rules Canada publishes the local source-derived answer.
Research note
This page explains a research process, not legal or arboricultural advice. Confirm the current rule with the municipality and use a qualified arborist where tree health or structural risk is in question.