It made negative emotions in people stronger. The trees feed on blood, so the more they encourage others to spill it around them, the bigger they can grow.

For some reason we weren't really effected by it until we got close to them...

[Overhead, one of the red blossoms begins to fall--]

I had a bit of a mental breakdown and I still have nightmares about it, but I'm not planning to talk about it to anyone.