In some high schools and colleges, a relatively large club or group of people who get together underneath campus trees in grassy areas and just talk. Members are often students with emotional or societal problems who get their feelings out with people who listen, much like a therapy session, except in a much more relaxed manner. Many times, conversations vary from these to much more random topics, and some societies have been known to have drug-high clubs inside of these, continuing with the so-called "healing," but this isn't too common.
"Loomis' Tree Society rep was yelling at everybody to join... I think it's supposed to be fun or something."