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!
Deuteronomy 25:4
25:4 You must not muzzle your ox when it is treading grain.