The answer to that question was set forth quite concisely in a fairly recent Superior Court case. In that case a neighbor caused to be removed certain tree branches that hung over his side of the property. The person who owned the property in which the tree was located brought suit against that neighbor, and also other neighbors, to get a restraining order to restrain them from cutting her trees. The property owner asserted that the defendant neighbors cause the cutting down and destruction of parts of the tree without her permission. There were no disputes as to the facts so the parties proceeded to ask the court to grant what is known as summary judgment which is a procedure whereby the judge rules on the undisputed facts as to what the law is. Here the judge found that the case law in Massachusetts recognizes the right of self-help by which a property owner can cut the limbs or branches of a tree that invade his property so long as the cutting is done at the property line. Citing from two different cases the judge quoted language from those cases as follows: “The neighbor… is… not without remedy. His right to cut off the intruding boughs and roots is well recognized” and from another case “A neighbor has the right to remove so much of the tree as overhangs his property”. The court found that the right to self-help is not confined to those parties who can show that the property was sufficiently damaged to justify their right to exercise self-help. The remedy is open to any party whose property is invaded by intruding boughs and roots. The court ruled that the defendants had the right under the law to cut the overhanging branches from the plaintiffs tree to the property line provided that the cutting is done solely on the defendant's property.

 

So using the teachings of that case, you would have the right to cut the branches from the hickory tree that overhangs your property up to the property line between you and your abutting neighbor. Notwithstanding having that right, you should probably, as a matter of courtesy, tell your neighbor that you intend to have the tree trimmed. Your neighbor might even be interested in having the lambs on their side of the property trimmed as well so perhaps you could split the expense with your neighbor. It may also be less expensive if the arborist were able to access the tree from your neighbor's property.