What is the movie?

So I have been racking my brain on this one for a long time. There is a movie out there, quite some time old, that focuses on the movement of the trees, them moving all together. As if the movement is talking, a force. I can't for the life of me remember what the movie is. It also deals with someone important in the movie dying, I think. So if anyone out there knows, PLEASE please help me.

~Allison