maintains a surprisingly buoyant tone throughout 
(ROOT (S (VP (VBZ maintains) (NP (DT a) (ADJP (RB surprisingly) (JJ buoyant)) (NN tone)) (PP (IN throughout)))))
(ROOT (S (VP (VBZ ) (NP (DT ) (ADJP (RB ) (JJ )) (NN )) (PP (IN )))))