Has the world of the future cut down all the rainforests yet? We're not totally sure. Trees make a few appearances, visually and in speech. When Hiro's getting a tour of the Babel/Infocalypse stack from the Librarian, one of the artifacts he sees a representation of is a tree:
"The treelike structure is a Yahwistic cult totem from Palestine. It's called an asherah. It's from about 900 B.C." (28.14)
The Librarian introduces it as a "totem of the goddess Asherah" (30.2), which is a big deal, since Asherah (known under various names) was widely worshiped in the ancient Near East and Mediterranean. Another of her symbols might ring a bell: "'The Sumerians knew her as Nintu or Ninhursag. Her symbol is a serpent coiling around a tree or staff: the caduceus'" (30.6). Yes, folks, the symbol for medicine came from a form of ancient goddess worship.
Sometimes it's the fruit of the tree, not the tree itself, that's the focus of discussion. As Hiro summarizes the events in Genesis, "'Eve, as I recall, is considered responsible for getting Adam to eat the forbidden fruit, from the tree of knowledge of good and evil. Which is to say, it's not just fruit—it's data'" (30.51). Trees can represent knowledge, then. Good to know.
Stick with us for a moment as we leap into the world of metaphor: so we've got a snake coiling around a tree. What else is treelike, with multiple parts branching off but all connected, with a complex structure that is symmetrical and evolving? The brain. And the Asherah virus, Hiro hypothesizes, can "'head like a bullet for the central nervous system and take up permanent residence in the cells of the brain—coiling around the brainstem like a serpent around a tree'" (56.30). The virus—like medicine—intervenes in the brain.
In other words, Shmoopers, all this tree talk isn't just some hippie nonsense. Nope, instead it's a potent metaphor for human evolution, knowledge, intervention, and susceptibility. Nothing peace-loving about it.