Tree
In general, trees represent the deepest and most significant intellectual concepts: the ones that come to us most directly from the Lord. This varies depending on us and our states: the people of the Most Ancient Church, who were in a state of loving the Lord, understood truth automatically and internally through what the Writings call "perception"; people in lower states (including most of us) have to work a little harder to learn it from the Word and by willing to follow the Lord. In other parts of the Bible, especially in the prophets and New Testament parables, the meaning of "tree" is broader, meaning not just a person's intellectual concepts but the whole person.
'Trees,' as in Joel 1:10-12, signify knowledges.
Jeremiah 44:25
25
Thus says Yahweh of Armies, the God of Israel, saying, You and your wives have both spoken with your mouths, and with your hands have fulfilled it, saying, We will surely perform our vows that we have vowed, to burn incense to the queen of the sky, and to pour out drink offerings to her: establish then your vows, and perform your vows.