Trees represent nations or kingdoms or peoples.
Cedars - Lebanon
Palm - Egypt
Plane tree - Jericho
Mustard tree - kingdom of God.
Olive tree - Jews
Wild olive tree - gentiles
Fig tree - students of the law
etc.
It helps to understand the Ezekiel’s context.
The ruler of Babylon, King Nebuchadnezzar, lay siege to Jerusalem and took the King of Judah, the royal family, nobles, upper class and priests into captivity in 597BC. Ezekiel was one of the priests sent into captivity in Babylon. He was commissioned by God to prophesy to the exiles in captivity up in Babylon.
Ezekiel’s message is that the people of Judah are responsible for their own exile because they were unfaithful to the covenant. Part of his message of repentance is that God can raise up other nations, kings and peoples as a means of judgement and that if the people of the nation of Judah repent, God can turn around and raise up the Jews above other nations. Ezekiel will explain what will happen to the tree of Judah if the Jews repent…
Every small bird will nest under it,
all kinds of winged birds will dwell
in the shade of its branches.
(Ezekiel 23:17)
Birds represent gentiles. The new tree of Israel when they return from exile will be a home for the Gentiles who will worship God alongside the Jews - if the Jews repent and are faithful to the covenant (True, it is planted; but will it thrive? Ezekiel 17:10).
Jesus uses the exact idea of birds nesting in branches from this passage in the parable of the mustard seed.
it is the smallest of all seeds, but when it has grown it is the greatest of shrubs and becomes a tree, so that the birds of the air come and make nests in its branches." (Matthew 13:32)
The mustard tree is the kingdom of God. Gentiles will find a home in it’s branches. Using ideas from the Hebrew Scriptures by hinting at certain passages is a very rabbinic way of teaching.
-Tim-