Question

and the wonderful wind is shaking the tree. explain the line.

Answer 1

it means the wind which is blowing saking the tree..

Answer 2

Heya!

Wonderful wind is shaking the tree,
It walks on the water and whirls the mills,
And talks to itself on the tops of the hills

This line is describing the beauty of the world where there are trees shaking due to the wind. It says, this world doesn't lack anything until you don't know how to respect what it has. This poem talks about the precious and beautiful nature.

Hope it helps!