I was drawn to this book again and again as a child, and I discovered that my (then) three-year-old daughter also wanted me to read it to her repeatedly. The book has given rise to numerous interpretations, and I myself have viewed it differently over time. Some people have a negative, visceral reaction to the book because they believe they are required to see it as a positive and uplifting tale of giving, something they cannot manage to do. These days, we are accustomed to sanitized, upbeat children's tales, but great children's literature has not always spared children the horrors of the world, and it has not always clearly stated its morals; more often, the morals are implied and are absorbed emotionally through the reading. We must not forget that Shel Silverstein was a biting satirist (consider such poems as "Almost Perfect But Not Quite.") It's just like Shel Silverstein to take the guise of a gentle little children's story to skewer the faults of humanity. Yes, "The Giving Tree" is a very disturbing book, but perhaps it's disturbing because it's meant to be. Many Christians (including myself initially) have thought of this as an allegory for Christ's sacrifice. I can certainly see why people think this is a Christian allegory: the tree, like Christ, gives itself entirely for the boy, even to the point of abject humiliation. If it is a Christian allegory, however, it is the disturbing tale of Christ's terrible, painful, continuous rejection by man, and not the heart-warming tale of unconditional love and forgiveness many Christians take it to be. There is no repentance in "The Giving Tree," and therefore no real forgiveness. Some take it as a tale of unconditional parental love, but if it is, it is again a painful tale: a tale of the child who never, his entire life, truly learns to appreciate his parents.
Environmentalist read it as a tale of man's selfish exploitation of nature.
Feminists regard it as a story of man's subjugation and abuse of woman and woman's failure to stand up for herself (the tree is a "she"). The fact that the book can speak to so many people on so many different levels is, I think, evidence of its subtlety and irony. It really can work on more than one level, if you want it to. But we err, I think, if we assume this is a "sweet" and positive tale. It is sad, but this is almost cathartic, because life, too, is sad. Few readers come to this book expecting the reality and complexity and vaguely drawn morals we get from the harsh Greek myths and the stark Bible stories and the creepy old fairy tales, which were the staples of past generations. Today we expect to encounter cleaned-up, upbeat, didactic stories where everyone learns his lesson: learns how to share or to tolerate or to be nice, a simplicity that is typical of so much children's literature today. But life does not always order itself according to neat story lines in which the bad guys suddenly become good by the third act. Children's literature such as The Giving Tree plays a valuable role by helping children (and even the parents who read it to their children) to wrestle with the ugly, beautiful, and complex truths of the world. It helps children to begin processing, very early on, the powerful and often disturbing visceral emotions these truths awake.