How does menteiths speech foreshadow the tragic end that approaches Macbeth?

In Menteith's speech in Act 5, Scene 2 of Macbeth, he mentions that Birnam Wood is moving, a prophecy that ultimately leads to Macbeth's downfall. This foreshadows the approaching army using tree branches as camouflage to conceal their numbers and approach Macbeth's castle for the final battle. It signifies the fulfillment of the witches' prophecy and how Macbeth's actions will ultimately lead to his tragic end.