Anyone know what this disease is afflicting this maple? I chopped it and left a relatively healthy looking 1ft of it in the ground for future bonsai use, and want to know how to treat it (if treatment is possible) in case the infection comes back full force.

The growths shown are dry and woody.

Looks like it is barking up. Which species of maple is it?

I used a tree identifier, and it might actually be sweetgum. I'm not exactly confident in that ID, though. This is a close up on one of the leaves, just in case anyone can ID it with confidence.

What does "barking up" mean?

Ok, turn out it IS a sweetgum, and I did some research on diseases that might affect it. Apparently "corky" bark is often mistaken as a disease, but is perfectly normal.