Deuteronomy 20:19-20

19“When you besiege a city for a long time, making war against it in order to capture it, you shall not destroy its [fruit-bearing] trees by swinging an axe against them; for you may eat from them, and you shall not cut them down. For is the tree of the field a man, that it should be besieged (destroyed) by you?

20Only the trees which you know are not fruit trees shall you destroy and cut down, so that you may build siegeworks against the city that is making war with you until it falls.