Here's why:

* Personification is a figure of speech where human qualities are given to inanimate objects, animals, or abstract ideas.

* In this case, the tree is being given the human ability to "raise its head". Trees, of course, don't have heads or the ability to move them.

* The sentence is suggesting that the tree is actively seeking the sun, just like a person might turn their head towards a source of light.

This use of personification makes the tree seem more alive and relatable, creating a vivid image in the reader's mind.