Trees 3

This program runs under Windows, Mac OSX and Linux (under WINE).

Trees (© Sean Crist and Tony Kroch) is easy-to-use software for drawing syntactic trees and displaying them on screen and in documents. It implements a form of lexicalized Tree Substitution Grammar, which allows the construction of phrase structure trees in an intuitive way, and it supports applying grammatical movement rules to syntactic trees to create syntactic derivations. Click on the above animation for a demonstration of how the program works. Trees is downloadable from this site.

Trees has several uses for teachers and students of natural language syntax, including:

The program works with grammar tool files that specify words, grammatical structures, and processes of syntactic composition in lexicalized (optionally) grammar fragments. These fragments can be written by program users to suit their purposes and in pedagogical applications are normally written by the teacher for use with an assignment. There are archives available for downloading Trees which contain grammar tools and assignments that have been used in introductory and intermediate courses at Penn and elsewhere. Colin Phillips, currently on the faculty of the University of Maryland, has been using Trees in an introductory course and has written a review of an earlier Macintosh version of the program, available here, that appeared in number 3.7 of the linguistics newsletter GLOT International (home page: The program is also in use at the following universities: University of Delaware, University of Edinburgh, Georgetown University, Michigan State University, University of North Carolina, Rutgers University, Simon Fraser University, and University of Wisconsin.

Trees supports a wide range of structures and composition processes. There is special support for X-bar phrase structure but non X-bar structures are also permitted. Transformational movement is supported but simple derivations in Categorial Grammar, Generalized Phrase Structure Grammar, and Tree Adjoining Grammar can also be modeled. The program does not currently support the display of attribute-value matrices.

The program was developed under a grant from the University of Pennsylvania School of Arts and Sciences Instructional Computing Development Fund and is freely available to students and staff of the University of Pennsylvania. The program is also freely available to students and staff at universities that have purchased site licenses for the program.

Other users may download for evaluation purposes a demonstration version of the program which will expire after 30 days. After the demo period, the program must be purchased in order to continue functioning. The fee for individual users is either $25 or $50, depending on the version of the program purchased. For further information, please visit the Trees download page.

Trees 2 icon
Anyone who wishes to use the program in conjunction with a class must purchase a multi-user site license. For further information on the cost and conditions of a site license, click here.



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