The 57th prohibition is that when besieging a city, we are forbidden from cutting down fruit trees in order to cause distress and pain to its inhabitants.
The source of this prohibition is G‑d's statement1 (exalted be He), "[When you lay siege to a city...,] you must not wield an ax and destroy its trees, for they eat from them. Do not cut them down."
All forms of destruction are included in this prohibition. One who needlessly burns a garment or breaks an object, for example, transgresses this prohibition and is punished by lashing.2
It is explained in the end of tractate Makkos3 that one who cuts down useful4 trees is punished by lashes. Our Sages say, "The prohibition is from this verse: 'For they eat from them. Do not cut them down.' "
The details of this mitzvah are explained in the second chapter of tractate Bava Basra.5
