If the roots or branches have encroached into your yard and become a nuisance, you have the right to fix or “abate” the nuisance, but there are limits. Here are some guidelines:
Trim overhanging branches up to the boundary line – at your own expense. This right is called “self-help.” (See “What is self-help?”)
Trim, but don’t harm the health of the tree or destroy it. For example, cutting off too much of the canopy could jeopardize the tree’s capacity to photosynthesize. Cutting too much of the root system could cause the tree to become unstable and topple over. And pruning an oak between April and September could make the tree vulnerable to oak wilt, a fatal disease. It doesn’t matter that the tree may look funny after trimming it. The courts look at whether or not you are harming the tree’s health. If you don’t know what may harm a tree, consult a tree expert before cutting.
To find a tree expert or ‘arborist,” look in the Yellow Pages under ‘tree service,” look for the arborist’s membership in professional organizations, such as the Minnesota Society of Arboriculture (MSA), the International Society of Arboriculture (ISA), or the National Arborist Association (NAA) .
Don’t trespass onto your neighbor’s property to trim a tree or shrub. And technically, that means don’t even lean over the property line to make the pruning cut, unless you have the neighbor’s consent.
Don’t cut down a tree whose trunk is on the boundary line, unless you have the express consent of the owner on the other side of the boundary line.
Tip: Chat before you chop. Even though you are not legally obligated to do so, talk to your neighbor before you do major trimming on your neighbor’s tree. It’s the neighborly thing to do.