The ending does not follow Tree-ear to maturity, but it is clear from the hopeful tone at the end of the novel that Min and Tree-ear will continue to grow closer, and that Tree-ear will learn his trade well, and represent Min well, too. This, Min should grow more content as he ages, and Tree-ear will have been the catalyst that brought them together and help bind them as one. The author seems to want to show that Min is a man who is living in the past, and it has made him angry and even cruel. He is also full of pride, and cannot admit defeat. When he does, it simply makes him more angry and bitter. He must turn his back on his past and learn from his mistakes, rather than simply give up in defeat. When he returns to the future and begins to appreciate what he has, and what he has attained, he becomes and kinder and gentler man who can open up his heart to love again.

The author also wants to show that even the most angry and unhappy man can learn to love again. Tree-ear is a good and honest boy who always wants to do the right thing. He loves Crane-man, and he comes to love Min's wife, as well. They show him kindness, and he gives them his heart in return. It takes Min a lot longer to learn the lesson, but the reader learns he has a heart when Min gently breaks the news of Crane-man's death to Tree-ear. The author writes, "This other, detached Tree-ear noticed that Min's eyes were soft, his face gentle. It was the first time Tree0ear had ever seen...

Min and Tree-ear are almost even now, because they have both lost someone they loved, and so, Min has learned a lesson about love and can finally get over the anger and unhappiness of his past to move on with his future. He has also allowed himself to care for someone else and their feelings, and because of this, he seems much more hopeful and able to cope with the future as the novel ends.
In conclusion, Tree-ear is the main character in this story, but Min is the catalyst that holds the story together, because he is the man who teaches Tree-ear how to become a man, and he is the character who changes most drastically throughout the story, or undergoes an evolution in the story. He receives his royal commission, which validates his work and his life, but he becomes softer and gentler as he learns to care about Tree-ear. Min is at his heart a good and decent man who has not been able to deal well with pain and disappointment. Tree-ear does not undergo the same evolution; he simply grows up and begins to become a man. This is natural, but Min's evolution is much more difficult, because he must overcome his own self-made obstacles to reach it. By the end of the book, he is happier with himself and his life, and because of this, he can open his heart to Tree-ear and make him his own son, the son that will learn his trade and carry on his craft.

References

Park, Linda Sue. A Single Shard. New York: Clarion Books, 2001.