Whereas most sentences correspond to a well-formed subtree, Sporleder and Lascarides (2004) report that over 20% of the paragraph boundaries in the RST-DT do not correspond to a well-formed subtree in the human annotated discourse parse for that document.
to perform accurate and efficient parsing of the RST-DT at the paragraph level, the text should be segmented into paragraph-like segments that conform to the human-annotated subtree boundaries, just as sentences are segmented into edus.