I saw this Strange Growth on a tree when were down at Griffin Park in Los Angeles. I take the kids down there now a then to go see the trains and have some fun for the day. As far as I can tell this looks like a Liquid Amber but my tree judgment is horrible at best.
It is either a disease or some very bad pruning that has caused this poor tree to look like this.
-- Mo... For safety is not a gadget but a state of mind. ~ "Eleanor Everet" - www.thiswoodshop.com