"One Trilogy to Rull Them All"...
Yeah to my understanding, as well as the books, Treebeard looks over Isengard and Sarumon after destroying it...The book "The Two Towers" goes into it a little more, and also ends with the spider thing and frodo/sam...which is what they put at the beginning of Return of the King film version...It just confused me in the film because, until the extended addition, you didn't really realize that it was up for Isengard...
the Books sort of illude to the inevitable rise of Sauron (sp?) over Sarumon altogther...At the point in which Isengard is captured by the pissed off tree dudes, Sauron is becoming so powerful so quickly, the wizard puppet Sarumon is no longer needed...and the story sort of shifts away from him very quickly...Jackson did the same thing...he had a quick capture of Isengard similar to the book's vision, but didn't go into any dramatic fall of Sarumon himself...
I can't wait to see RTOTK, It was completely sold out throughout my entire area by 6 today...I had a final anyway too...Tomorrow I shall go...