When Zak innocently carves his and Crysta's initials into a tree, Crysta flies up and stops him, desperately saying he mustn't do that, holding his hand to the tree and asking if he can feel its pain. But since he lacks the empathic abilities that she and Magi have to commune with nature, he has no reaction and she releases his hand with a heartbroken expression.
Crysta and Magi conversing by a tree stump. When Crysta touches it, she looks like she's being burned. Magi comments on how this is beyond her powers and you can tell she's dangerously close to the Despair Event Horizon. When Crysta sees a familiar red stain on what's left of the tree, she flies above the canopy and sees that the wonderful sight from before has been replaced by a post-apocalyptic setting. She then notices some humans carrying what's left of the trees away.
Crysta: Humans did it...humans did it all.
When Zak makes his confession that the humans are destroying the forest and he was helping them. He states that Batty was right about humans and you can see that Batty really did not want to be.
Prior to this, as Zak is being questioned by the fairies about what's happening to the forest, Crysta furiously tells Zak, "You lied to me!" (earlier, he reassured her that the Leveler would not be able to reach FernGully and that he had nothing to do with it.note Though he didn't lie about it never coming to Ferngully, Hexxus tricked the humans into it) which in turn forces Zak to reveal the truth to the fairies. When she yells at him, she sounds absolutely heartbroken.
Seeing her crying alone on a tree branch later (pictured above) certainly doesn't helpnote she'd been curious to learn about humans, but now her faith in them has been shaken.
Crysta restoring Zak to his normal size as it's very likely they'll never meet again.
Crysta: What was done, now undo. Return you to the form that's true. Goodbye, Zak...
