She misses what is actually happening.

Nearby, a pair of teens sneak through the forest.
They are using a Phone App and Speaker to send out 'bear noises.'

It's just a fun prank.

For Jenni, however, it is 'danger.'
She hears the sounds get closer and climbs up higher...

She fails to realize which direction the sounds are coming from (thanks to an echo) and keeps looking the wrong way.

The guys get close and see the naked young lady in the tree.
They smile.

They spot her clothes and pick them up, scurrying off with them (after snapping a quick pic or two of the unaware nudist)...

While they are gone, the sounds have the opposite effect of Jenni's friend Lisa.

She knows that Jenni went this way and is concerned for her.

She sees no signs of a bear, nor does she any literal signs warning about them being in the area.

She eventually spots her friend up in the tree.

"Jenni?!? What's...what's going on?"

"Oh hey- did you see where that bear went?"
"There was no bear. Is that...why you are up there?"
"Yeah, they don't climb trees."
"That's...alright, then. Why are you naked?

...wait, never mind."
She figured out Jenni's 'logic' and sighs.

"One other question then."
"Yes?"
"Where are your clothes at," Lisa asks.