Korah was a man of the tribe of Levi, who together with Dathan and Abiram, led an insurrection against Moses and Aaron. Apparently their insurrection was prompted by their being out in the wilderness with no place to go. This happened after the Children of Israel had approached the land of Canaan from the south and had sent out spies to scout the land. Ten of the twelve spies said the land was too strong for them, that there were giants there. Moses then told the whole congregation they would all have to spend forty years in the wilderness until all that generation had died. In this story, Moses and Aaron represent the Lord. When Korah and his fellow rebels murmured against them and took fire from the altar and burned incense with it, they represented the profanation of mixing what is good (the fire from the altar) with what is evil (rebelling against Moses). The three rebel leaders and their followers were separated from the congregation and were swallowed up by a pit that opened in the earth. In our lives, evils need to be separated, too, and gotten rid of.

(Odkazy: The Apocalypse Explained 324 [6])

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.