v1-4: The lioness is Josiah, himself a picture of Jerusalem. His cub was Jehoahaz, who was taken to Egypt, 2 Chr 36.1-4; 609 BC.
v5-9: Jehoiakim was taken to Babylon, 2 Chr 36.5-8. The surrounding states had also attacked, see 2 Kings 24.2.
v10-11: The fruitfulness of Josiah, full of branches, yet all that came to nothing. Much blessing came during his reign, 2 Chr 34-35, but was seemingly forgotten. The vine image is used a number of times to describe Israel.
The truths of chapter 18 are applied here in a national sense. The past blessings could not save the rebellious people.
v12-14: The tree was uprooted and thrown to the ground, never again to bear fruit. The wilderness, the dry and thirsty land, refers to where Ezekiel lives with the captives. They knew this to be true.
No strong branch was left; the work of restoration under Josiah was totally lost, as his sons turned away from his godly example.