Symbolism, Imagery, Allegory
When David and Laurel first start hanging out, he brings her to some trails behind his house in order to show her something really cool: "two trees, a fir and an alder that had sprouted close together. Their trunks had merged and twisted, resulting in what looked like a tree that grew pine needles on one side and broad leaves on the other" (3.82).
Laurel and David chat about this super tree, before moving on gab about their families. But we'd like to linger for a bit. See, we think this crazy tree is actually a pretty good metaphor for Laurel's life. How's that? Well, Laurel's a faerie living in the human world, so in that sense, she's half human, half faerie, and she walks the line between those two realms. Just as the two trees of different species have grown together, her life has become a symbol of the union of the human and faerie worlds. She's literally two things in one.
Which means that, like the tree(s), Laurel displays characteristics of both parts of her heritage: As a faerie, she only eats plant matter, but because she's also of the human world, she consumes plant matter in the form of people-y foods, like fresh fruits and veggies (plus Sprite). She wears modern-people clothes like most humans do (hey, we're not hating on historical re-enactors), but because she's a faerie, she has to adapt the clothing to accommodate her blossom.
Sadly, we don't really have a good name for this tree-that-is-actually-two-trees. But that's fitting, don't you think? Frankly, it's just as hard to classify what Laurel actually is. Biologically, she's a faerie, but she has been living as a human since she was a kid. This means that socially, she's more human than faerie. The question is, does her biology or her upbringing influence her more? Here's hoping that, like the tree, Laurel will find a way to synthesize both parts of her identity so that she can have the best of both worlds.