The Forestry Act of Ontario provides that every tree whose “trunk” is on the “boundary” between adjoining lands is the “common property” of the owners of the adjoining lands...and...every person who injures or destroys a tree growing on the boundary between adjoining lands without the consent of the adjoining owner is guilty of an offence under the Act.
In a recent Toronto case, Owner "A" wanted to cut down a tree which was at the boundary line but appeared to be entirely on her property. Owner "B" did not want the tree cut down claiming that it was a boundary tree and therefore was common property. The Court ruled that the “trunk” of the tree includes the entire trunk from its point of growth away from its roots up to the top. While the tree trunk “appeared” to be entirely on Owner A’s land, the expert evidence established that a portion of the trunk base (even if under the soil) was on the boundary line. In the circumstances the Court ruled that the tree was common property and could not be cut down without the consent of the adjoining owner.