Adjoining landowners can find themselves in disputes over fences, overhanging branches, water rights, subjacent and lateral support and party walls. A boundary is every separation, natural or artificial (man-made), which marks the confines or line of division of two contiguous estates. A river or other stream is a natural boundary, and in that case the center of the stream is the line.
Boundaries are frequently marked by partition fences, ditches, hedges, trees, etc. When such a fence is built by one of the owners of the land, on his own premises, it belongs to him exclusively; when built by both at joint expense, each is the owner of that part on his own land. When the boundary is a hedge and a single ditch, it is presumed to belong to the person on whose side the hedge is. But if there is a ditch on each side of the hedge, or no ditch at all, the hedge is presumed to be the common property of both proprietors. A tree growing in the boundary line is the joint property of both owners of the land.
Disputes arising from a confusion of boundaries may be generally settled by an action at law. But courts of equity will entertain a bill for the settlement of boundaries when the rights of one of the parties may be established upon equitable grounds.
For example, there is no clear legal rule regarding trees that grow on the boundary between two properties. In some states, trees standing along a boundary line are the common property of the neighbors on either side of the boundary, and neither neighbor can remove the tree without the consent of the other. If a tree is on a neighbor's property but encroaches your property, you have the right to trim it up to the property line as long as it doesn't jeopardize the health of the tree, especially the roots. However, you must get permission to enter the neighbor's property if required. You cannot cut down a tree whose trunk is located on your neighbor's property, even if the branches stray onto your property.