Thou shalt not destroy the trees Which is to be understood of a general destruction of them, not of cutting down some few of them, as the convenience of the siege might require. Man's life The sustenance or support of his life.
Related Commentaries of Deuteronomy 20:19
Deuteronomy 20:19
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 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: