Final answer:
A tree branch hanging over the neighbor's property line is generally considered an encroachment and property owners have the right to trim branches that extend onto their property, subject to local laws.
Step-by-step explanation:
When a tree branch extends over the property line and hangs into a neighbor's property, this is typically referred to as an encroachment. In legal terms, encroachment happens when one property owner violates the property rights of another by building on or extending a structure to the neighbor's land or airspace. In the case of a tree, a branch that hangs over a property line can be considered a nuisance or an encroachment if it causes harm or is a potential threat. Property owners generally have the right to trim the branches of a neighboring tree that extend onto their property. It is important, however, to check local regulations and ordinances as they can vary greatly, and in some cases, there may be specific rules about who is responsible for maintenance or removal of the encroaching branches.