Deuteronomy 20:19

When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof, the various trees bearing fruits and nuts, by forcing an ax against them, by chopping them down with the customary swinging motion; for thou mayest eat of them, their fruit is able to sustain life, and thou shalt not cut them down (for the tree of the field is man's life), he depends upon it for food, to employ them in the siege, in the building of breastworks and trenches. The children of Israel were to remember that war should be waged with men only, not with trees whose fruit served for food. They were not to practice vandalism and ruthlessness.