actually its not based on anything, but has SOME things to do with the two wars
dead marshes...probably from tolkiens time as leiutenant in the battle of the somme...seeing his friends die
sarumans voice...hitler...he had a mesmerizing voice
treebeard and the ents...based on macbeth 'sir it seems to me as if the forest doth move' tolkien was disapointed when it was just some stupid people dressed as trees