Responsa for Bava Batra 50:14
פאפי יונאה עני והעשיר הוה בנה אפדנא הוו הנך עצורי בשיבבותיה דכי הוו דייקי שומשמי הוה ניידא אפדניה אתא לקמיה דרב אשי א"ל כי הואן בי רב כהנא הוה אמרינן מודי רבי יוסי בגירי דיליה
<b><i>GEMARA</i></b>. A Tanna has taught: 'Whether the tree is on higher ground than the pit or the pit is on higher ground than the tree.' If the tree is on higher ground than the pit, we can understand the prohibition, because the roots spread and damage the pit. But if the pit is higher than the tree, what reason is there? — R. Haga said in the name of R. Jose: Because the roots undermine the soil and damage the floor of the pit. R. JOSE SAYS THAT EVEN IF THE PIT WAS THERE BEFORE THE TREE THE OWNER CANNOT HAVE THE TREE CUT DOWN, BECAUSE THIS ONE DIGS IN HIS PROPERTY. THE OTHER PLANTS IN HIS. R. Judah says in the name of Samuel: The <i>halachah</i> is according to R. Jose. R. Ashi said: When we studied with R. Kahana we used to say that R. Jose admits that a man is responsible for damage of which lie is the cause.<span class="x" onmousemove="('comment',' Lit., 'for his own arrows.' V. supra p. 114, n. 3. ');"><sup>23</sup></span>
Teshuvot Maharam
A. Those parts of the beams which extended into A's portion belonged to him exclusively, and he had a right to cut them off, especially since the intervening wall belonged to him. Although the act of sawing and chopping weakened B's and C's structures, since the extension of the beams into A's room served no useful purpose to B and C, and because of their unnecessary weight were even detrimental, A had a right to cut them off. In any event, B and C are not entitled to any compensation for their loss, now that the act has been done.
SOURCES: Am II, 198.