The giving tree

As a child, the giving tree was one of my favorite books, it seemed so lovely and sweet, that this tree was willing to literally give herself to the little boy. I loved Shel Silverstein in general, especially his poetry books.
Looking back on it though, it seems the sweetness was incredibly one sided.
Of course I knew this at the time, it just wasn't very apparent, I was sort of apathetic towards the boy and just focused on the selflessness of the tree.
The book as I remember it seems like a metaphor for either unhealthy romantic relationships or motherhood, though I'm not sure Mr. Silverstein wrote the book with those intention.
As for the former, you could switch the tree and the boy with a couple (with a few adjustments obviously) and it would be a story about emotional abuse and manipulation.
And for the latter, It does make sense. So many mothers give and give and give with no thanks and no appreciation. But of course while these mothers love their children, doing a job (which is arguably what motherhood is) without respect is tiring and depressing, so why is the tree always happy?
You might say "She's happy because the little boy is happy."
Even the most selfless person in the world needs love sometimes.
And the boy isn't always with her, he goes for years without speaking to her, who knows what kind of emotions she went through when the person that meant the most to her wouldn't talk to her for years?
Or maybe it's a metaphor for adulthood. You're easily satisfied as a child, but as you get older, you want more and more, and you're willing to take from your friends and your family.
In closing, I look at the book as a lesson, don't give everything you have to someone who doesn't deserve it, or else you'll end up a stump with a geriatric man's ass in your face. Unless you're into that sort of thing, in which case, this just got awkward.


P.S. Why did the little boy have to mutilate his friend to make a house? Why didn't he just cut down another tree?