The PEAR Tree package provides methods to read and manipulate trees, which are stored in database (via DB, MDB and MDB2)or an XML file. The trees can be stored in the DB either as nested trees or as simple trees that use parentId-like structure. There are two ways of retreiving the data from the place where they are stored, one is by reading the entire tree into the memory - the Memory way. The other is reading the tree nodes as needed (very useful in combination with huge treesand the nested set model).

The package offers a big number of methods to access and manipulate trees. The package is designed that way that it is possible to convert/copy tree data from either structure to another (from XML into DB). However, currently XML data can only be read from a file and accessed.

In the latest version, 0.3.2, an MDB2+Tree problem where MDB2 doesn't contain getTextValue method, and Tree/Memory.php method getElementContent() that was not working have been fixed.