Fruitful fruit literally means that there are many and big fruits. It is used here as a metaphor for the return of a bumper harvest. Poetry reveals the truth that giving will eventually pay off by metaphor, and it is full of optimism and upward spirit.
These words are selected from the modern poem Calendar:
A calendar is like a pine tree
A page calendar
is a petal
If the petal falls
, it will bear rich fruit.