Most of the characters are fleshed out, have their motivations, and rich inner worlds of their own. The way the author spoke about trees made me notice them more in my life and left me in awe.

My issue with this book is about the protagonist/catalyst of the bulk of the story.

Olivia has zero inclination towards trees, and is made the main person motivating the group. I despised the way the author treats her - a sexy saviour , if I may. Why was she chosen, of all people to hear the trees? There were so many others, for example Mimi or Patrica or Douglas or Neelay who could have made a much better "prophet."
The author tirelessly keeps reminding us that she is beautiful and hot and young. Imagine, someone wanting to cut down a tree you're perched on, stops, stares at you and says, "Holy crap, you're gorgeous!"

Her untimely death breaks the group apart, for understandable reasons. But, how convenient that to show that Olivia has something special about her, two of the five are in love with her. Of course they are, how else would the readers know there is something special about this young lady?
Instead of focussing on giving her actual motivations, the author takes a shortcut and spends the rest of his time making up for this error by creating a blank, uninteresting protagonist.
For me, the book picked up again after her death, which is saying a lot about how badly she was written. A box of fortune cookies could replace her.
The author had such a great opportunity to make a truly well rounded character like he did the others, but squandered it away in a weird male fantasy.

Did not like the way the protagonist was written. It distracted me so much. I went into this book hoping to find someone to look up to, and instead have been shortchanged with a lampshade protagonist serving a male fantasy. She could have been so, so much more. Also, writing in symbolic heavy language does not make a book likeable - but that is more likely to be a shortcoming at my end.