[It's not his voice that causes her to glance over him, but what she can sense from him as he approaches, and so she's already looking over at him when he speaks. Another sword...?

But by now she's getting used to sensing that, so she only blinks as she turns to face him a bit more, her expression softening into something more neutral as she puts her hands on her hips.]

... Ears aren't always a requirement, though. [Even though they usually are -] Plus, this is a weird tree, since most trees don't try to grab you. So maybe it can hear me.

[Clearly her logic is sound. But at least tree is still too busy nursing it's burn to try to get all grabby again.]