( Mountain ( stream ( tree frog ) ) )
(ROOT (NP (NP (NNP Mountain)) (NP (NN stream) (NN tree) (NN frog))))
Mountain stream tree frog
(ROOT (S (NP (NNS Streams)) (ADVP (RB often)) (VP (VBP start) (PP (IN in) (NP (NNS mountains)))) (. .)))