The geocaching world is rich with it's own language, terminology and acronyms. When starting out with this game there is quite a steep learning curve to understand the way other players talk and write about the caches they place and hide. However; it doesn't take too long for the lingo to stick and you will soon be at GZ with your GPSR looking at the BOT hoping that you don't DNF the nano!
Base of tree. A very common hint especially when looking for caches in the forest or parks.
This walking trail is a mix of (mainly) hard packed surfaces and small sections of sandy track.