What does Daniel 4:23 mean?

You saw a holy messenger coming down from heaven, saying, 'Cut down the tree and destroy it, but leave the stump and roots in the ground, held with iron and bronze bands, out in the grass. Let him be soaked with dew and live with the animals until seven years pass.' Daniel 4:23 - Modern Text Bible

(Daniel repeats the part of the dream about the tree’s destruction and the stump being left, connecting it to what will happen to Nebuchadnezzar.)