The good tree (Touba) mentioned in the Koran existing in paradise, refers to the good deeds:
Those who believe and perform honorable deeds will find gladness and the finest journey end (13:29)
Do you not consider how God makes up a parable? A good word may be compared to good tree whose root is firm and whose branches soar up into the sky. It yields its food each season with its Lords permission.
God composes parables for mankind so that may be reminded. (14:24-25)
The Infernal tree (Zaqum) is also a tree existing in Hell; it is mentioned in the Koran and refers to the evil acts:
Abad word may be compared to bad tree, it will be uprooted from the face of the earth, it has no foothold (14:26).