A tricky puzzle. Make sure you're not barking up the wrong tree.

It is on a tree.

Or, rather, it's on more than one tree.

Walk from the obelisk into the jungle, and you'll come across trees covered in light green moss patterns.

Find part of a circle on the center tree. Line it up with the rest of the circle on another tree. Trace upward, then along the left branch, all the way down to the ground behind you.

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Look for green bark.

Look for circles in the bark.

Try to get a line that goes up into the trees.