Who wrote this?

Who wrote this? I need to know.

The tree has entered my hands,
The sap has ascended my arms,
The tree has grown in my breast-
Downward,
The branches grow out of me, like arms.

Tree you are,
Moss you are,
You are violets with wind above them.
A child - so high - you are,
And all this is folly to the world.

Let me know please.