Deuteronomy 20:12

20:12 If it does not accept terms of peace but makes war with you, then you are to lay siege to it.

Deuteronomy 20:19

20:19 If you besiege a city for a long time while attempting to capture it, you must not chop down its trees, for you may eat fruit from them and should not cut them down. A tree in the field is not human that you should besiege it!