That shot was a great contrast to the beginning of the series.

Episode I began with Aku, an 'evil tree' surrounded by the ruins he had created, and episode CI ended with a tree that was symbolic of his cruelty, now surrounded by the landscape that had once been taken away. I know the intention was more on showing that Ashi will live on in Jack's heart, but I can't help but think there's a bit more to it than that...