When they told it to Jotham, he went and stood on the top of Mount Gerizim, and lifted up his voice, and cried, and said to them, Listen to me, you men of Shechem, that God may listen to you.
The difference between a fable and a parable is that a parable teaches a lesson by mentioning occurrences that actually happened, or at least, could have happened, whereas, the "dramatis personnae" in a fable are animals, trees, etc.  This fable and the brief one in  2 Kings 14:9 are the only two fables in the Old Testament.