Complex sentence: Dungy is listed as not only a part of the Bill Walsh coaching tree, but also a part of the Marty Schottenheimer coaching tree, the Dungy tree grew from the roots of the Pittsburgh Steelers' dynasty of the 1970s.
Split into simpler sentences: Dungy is listed as not only a part of the Bill Walsh coaching tree, but also a part of the Marty Schottenheimer coaching tree. The Dungy tree grew from the roots of the Pittsburgh Steelers' dynasty of the 1970s.