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.

Look just left some tangled roots to see part of a circle on a tree. Line it up with the rest of the circle on another tree. Trace the path through the branches down onto the trunk of a nearby tree.

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Look for green bark.

Look for circles in the bark.

Try to get a line that goes up and back down the trees.