a package offering support for drawing tree diagrams, and is especially suitable for linguistics use. It allows trees to be specified in a simple bracket notation, automatically calculates branch sizes, and supports both DVI/PostScript and PDF output by use of pict2e facilities.
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.