( ( The ( unifacial cambium ) ) ( ( ( allowed plants ) ( to ( ( grow ( as tall ) ) ( as ( 50 metres ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ unifacial) (NN cambium)) (VP (VBD allowed) (NP (NNS plants)) (S (VP (TO to) (VP (VB grow) (ADJP (RB as) (JJ tall)) (PP (IN as) (NP (CD 50) (NNS metres))))))) (. .)))
The unifacial cambium allowed plants to grow as tall as 50 metres.
(ROOT (S (NP (JJ Vascular) (NN tissue)) (VP (VBD allowed) (NP (DT these) (NNS plants)) (S (VP (TO to) (VP (VB grow) (NP (JJR taller)))))) (. .)))