peace,
2) But, who's the "tree" and who's the "stick" in this analogy?
I thought someone might bring that up.

Analogies are never perfect representations. I was mainly highlighting the overall theme of growth by way of support. As sister Elke implied, I do not see one partner as only the stick or only the tree, but interchangeable. People have growth phases as well as static phases, hence sometimes they will be the tree, sometimes they will be the stick,
they key is the direction, and that is ascension, towards the light/sun.
2) But, who's the "tree" and who's the "stick" in this analogy? .. The stick analogy shows that as the tree grew bigger, the first stick will have to be "divorced" from the tree and the "ex" will be replaced with a new stick that physically & momentarily, fits the tree's new "interest".
lol @ divorced stick. What's next... each tree can have four sticks? As long as the sticks have baby sticks of course!

... The quran says spouses are like garments to one another. The clothes we choose function to protect and support our needs/wants, in return we have to take care of the clothes so that they last longer or change accordingly to our interests..... In this analogy, both the garment and the body that wears it "grow" overtime and "adapt" to each other.
What kind of freaky clothes do you have that grow along with you?

You must let me know the name of your tailor.
Whereas, the stick in the analogy you posted here, remain static, and in it's "interest" the tree plays no role what so ever. ... Ah, another lesson is gained from your analogy...
I think technically, the stick would be standing stronger too due to the tree being there.
4) What if two "seeds" are planted near to one another so that they grow side by side and give support just like the sticks?
Will they grow stronger together or become weaker? ...In what conditions?
Unfortunately, my child mind had not developed enough to also check this possibility. To be fair, my mum had her hands full with my over-inquisitve mind as it was, so perhaps it was lucky I did not suggest this, may have driven her over the edge.