ROT being Royal Oak Trail. And I don't think its a ROTten cache but you might when you find it. And its not on the ground or in any litter so there's that :) Look at all the hints you are getting and I'm not a big hinty person. I must like you :) It's simply a cache in a tree...or is it? 
. Oh and its not even one of those little acorn caches that I love so much..hokey doodle. I must really like you.
As always...have fun 