This paper gives an Abstract Categorial Grammar (ACG) account of<cite> (Kallmeyer and Kuhlmann, 2012)</cite>'s process of transformation of the derivation trees of Tree Adjoining Grammar (TAG) into dependency trees. We make explicit how the requirement of keeping a direct interpretation of dependency trees into strings results into lexical ambiguity. Since the ACG framework has already been used to provide a logical semantics from TAG derivation trees, we have a unified picture where derivation trees and dependency trees are related but independent equivalent ways to account for the same surface-meaning relation.