Protagonists: What if a group of people are put together to try and discover why the trees are failing?

Antagonists: What if the trees are failing due to an evil wizard? Or maybe a collective of 7 demons on the other side? One per tree?

Okay, so there's no rule that says you have to have one single protagonist. you can have more than one. Or you could have one and the group that is that person's support network. So start telling me about these people, not necessarily any of the specific individual people if you don't know that yet, but just tell me about the people themselves. What are they like? How did they discover the problem? did someone deliberately put them together to solve this problem? Or was it fate? Does each one contribute a specific skill that the others don't have, and that's why the group was assembled?

Go. Just start explaining. Remember that you can change your mind about any of it at any time. My brainstorming often consists of, maybe this person has this trait... Or no, maybe not because of this reason... Etc. etc. Think out loud until things start to sound right, or at least, close to right.

Cheers,
Michelle