Mature trees add beauty and character to any neighbourhood, while providing cool shade in the summer, wildlife habitat and clean air. But trees can also cause tension between neighbours, particularly where they grow across property lines. With the increasingly intense “freak storms” that climate change brings, added to our normally tempestuous weather, trees are subjected to a great deal of wind.
This raises some questions: When must I cut my trees? Do my neighbours have the right to trim my trees when they cross onto their properties? And, can I trim municipally owned trees that are in front of my house?
If a dead or dying branch or tree is in a location where it will cause significant damage when it falls, the owner of the tree has a duty to take reasonable care. This includes the duty to trim back a tree or a branch that is obviously a threat to the neighbours.
There is even a case where an injured neighbour was awarded substantial damages from a neighbour that refused to deal with his trees. In Hayes v. Davis, which went as far as the B.C. Court of Appeal in 1991, the Hayes had told their neighbour, Davis, that they were concerned that his trees swayed toward their house during windstorms. They asked him to remove the trees; but he refused, saying he had no money. A few months later, two trees were blown down in a severe storm, injuring Mrs. Hayes. Mrs. Hayes sued for damages for nuisance, and won. Davis, having failed to take reasonable steps to address foreseeable risk of damage or injury, was ordered to pay $65,000 in general damages and nearly $3000 in special damages. The conviction stood on appeal, and Davis’ attempt to appeal to the Supreme Court of Canada was refused.
In an Ontario case, Doucette v. Parent in 1996,  O.J. No. 3493, the Parents’ diseased tree fell during a windstorm and damaged Doucette’s property. However, Doucette’s claim was dismissed. Although there were a few bare branches, neither party knew that the tree was sick. Growing trees is a natural use of land that does not attract liability; only dead or dying trees and branches that are noticeably liable to cause damage need to be cut back.
In some municipalities, such as Toronto, Barrie and London, by-laws prohibit the removal or injury of mature trees even on private property, and any pruning must be done properly. Penalties for by-law offences may include fines, rehabilitating the land and replanting trees (see www.envirolaw.com for more information on these by-laws). A hazardous, dead or dying tree may be removed without a permit, but only if the tree’s condition has been certified by an expert.
When it comes to trees that overhand the property line, your neighbours usually have the right to cut the branches from your tree which are on their side of the fence. Whether for safety or aesthetic purposes, they must still trim the trees properly, and can’t enter your property to do it. They could be liable if they damage the trees, since the courts recognize trees as something of value. Obviously, it’s best to discuss the matter with your neighbour before taking out your saw.
When it comes to municipal trees in front of your house, homeowners have an obligation to inform the municipality of any vulnerability, but cannot trim or alter them in any way. Municipalities, unable to monitor every tree, are generally happy to receive the tips and send out crews to take care of them.