פירוש על בבא בתרא 2:12

סמוך לשדה חבירו – whether it is a bright field lacking shade or it is a cultivated field in which trees grow.

Introduction Mishnah twelve deals with distancing trees from the another person’s fields.

אלא אם כן החיק ממנו ארבע אמות – in order for the word of the vineyard, for when he ploughs his trees, there should not be a need to bring his plough into that (i.e., the field) of his fellow. And these words refer to the Land of Israel, and places like it where their ploughs are long. But in Babylonia and in other countries where their ploughs are short, a distance of two cubits is sufficient, and especially with vines to [other] vines, and trees to trees, where two cubits are sufficient. But, one who comes to plant in an orchard near the vines, even in Babylonia, and places similar to it, one has to make a distance of four cubits.

A person may not plant a tree near another’s field unless it is four cubits away, no matter whether it be a vine or any other kind of tree. If there was a wall between, each may plant up to the wall on either side. If its roots entered within the other’s property, the other may cut them away to a depth of three handbreadths so that they shall not hinder the plough. If he dug a cistern, trench or cave, he may cut them away as far down as he digs, and the wood shall belong to him. A tree planted close to another person’s property will eventually grow onto that property, both above and below ground. Therefore a person was required to distance his trees four cubits from another’s property. The remainder of the mishnah is basically refining this general law which we learn in section one. In 1a we learn that the law is not applicable if there is a fence, which would prevent the leaves of the trees from entering into the neighbor’s property. If there is a fence than one may plant his trees right up to the fence. In 1b we learn that if the roots of your neighbor’s tree enters your property you are allowed to remove the roots that are less than three handbreadths deep, so that the plow will not get caught on them. Finally, we learn at the end of the mishnah that if one was digging something on his property and the roots interfered, he can cut them away even further than the aforementioned three cubits.

מעמיק שלשה טפחים – the owner of the field whose fellow’s tree roots went out into his field, he cus them at a depth of three handbreadths and does not worry.

Questions for Further Thought
• In the last clause of the mishnah it says that the trees (i.e. cut away roots of trees) are his. Why doesn’t he have to return them to the owner of the tree?

והעצים שלו – of the owner of the field, and this will be the place where he ploughs sixteen cubits or more from the tree of his fellow, but less than this, the wood belongs to the owner of the trees, for up to sixteen cubits, they absorb sap, more than this, they don’t suck the sap.