Deuteronomy 20:18-19

18That they teach you not to do after all their abominations, which they have done unto their gods; so should ye sin against the Lord your God.

19When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by forcing an axe against them: for thou mayest eat of them, and thou shalt not cut them down (for the tree of the field is man’s life) to employ them in the siege:12