tree parser vs stream parser

tree parser vs stream parser

Looking for an explanation on tree parser vs stream parser.
From what i have been researching the JSON build-in parser in android is a
tree parser and the Jackson Json parser is a stream parser. Also,
android's xml pull parser is a stream parser.
My question is what is a tree parser and could you explain the difference
between a stream and tree parser? From Google I/O presenter mentioned tree
parser hog much more battery life and should be avoided in place of a
stream parser.