Once there was a tree, and a bird landed on it and started pulling the leaves off. Eventually a boy came along and ate the bird, and the tree grew back its leaves.
This happens on a regular basis
Might it be
'The changing of seasons' in which the bird would be autumn or abscission (The process in which a tree loses its leaves). The boy would then be the change to a next season (getting rid of the bird). In which the tree starts to get his leaves back. And of course the changing of seasons occurs on a regular basis
No laughing, but:
The boy's name was Robin. So:
Robin ate the robin who was robbin' pieces of the Picea Rubens, and the Picea Rubens re-budded.
Answered before the hint was included.
This mimics the story of
The Selfish Giant by Oscar Wilde (one of my favourite tales!).
WARNING: SPOILER ALERTS WILL FOLLOW.
Once there was a tree,
The Giant's beautiful garden.
and a bird landed on it
The Giant surrounds his garden with a high wall and a notice-board (the bird; "bird" sounds like "board") reading TRESPASSERS WILL BE PROSECUTED.
and started pulling the leaves off
There suddenly came an eternal winter in the Giant's garden for which all the leaves fell off and the trees bore no golden fruit.
Eventually a boy came along
and ate the bird
The Giant took a great axe ("axe" sounds like "ate") and cut down the high wall.
and the tree grew back its leaves.
The Giant puts a crying boy up into a tree, wherefore it blossoms and the Garden stays beautiful again, forever and ever.
Both stories are split into three parts:
The tree with the bird. (Expulsion from the Garden)
The bird pulling off the leaves. (Dances of Eternal Winter)
The leaves grew back and the bird is gone. (The Return of Spring)
The boy ate the bird which had the leaves in it so now the boy as the leaves in him because he ate the bird. When he died, he became decayed into the ground and into the soil. So the leaves in the boy are now in the soil which helps the tree grow back the leaves.
The boy threw away the part of the bird which had the leaves in it and now that part gets decayed in the soil. So the soil now has the leaves which helps the tree grow back it's leaves.