qtree package consists of QobiTree, a package of tree-drawing macros
written by Jeff Siskind, and a front end that allows trees to be specified
in bracket notation, using whitespace to separate tokens. Tree nodes can
have labels of any size or complexity, and are automatically arranged on the
page, usually with quite good results. Provisions exist for fine-tuning the
default layout. The front end also centers trees (by default) and provides
some other nice features.