But you may destroy the trees that you know do not produce fruit. Use them to build siege works against the city that is waging war against you, until it falls.
KJV
Only the trees which thou knowest that they [be] not trees for meat, thou shalt destroy and cut them down; and thou shalt build bulwarks against the city that maketh war with thee, until it be subdued.
ASV
Only the trees of which thou knowest that they are not trees for food, thou shalt destroy and cut them down; and thou shalt build bulwarks against the city that maketh war with thee, until it fall.