How has the poet described a tree earlier in the poem ‘The Heart of the Tree’?

In the very first stanza of the poem the poet has presented three ways to describe a tree.

• He has called the tree a ‘friend of sun and sky’.
• A tree resembles a flying flag on a high beautiful shaft.
• Moreover, a tree is a heavenly home of sweet singing birds near the sky.

For an elaborate explanation please read our line by line analysis of the poem.