( ( This work ) ( often ( ( involves ( ( ( ( ( ( tracing ( patterns ( of ( atmospheric ( CO ( 2 concentrations ) ) ) ) ) ) ( over ( ( ( very long ) spans ) ( of ( geologic time ) ) ) ) ) , ) ( ( using ( such methods ) ) ( as ice-core ) ) ) and ) ( tree-ring studies ) ) ) . ) ) )
(ROOT (S (NP (DT This) (NN work)) (ADVP (RB often)) (VP (VBZ involves) (S (VP (VP (VBG tracing) (NP (NP (NNS patterns)) (PP (IN of) (NP (JJ atmospheric) (NNP CO) (CD 2) (NNS concentrations)))) (PP (IN over) (NP (NP (ADJP (RB very) (JJ long)) (NNS spans)) (PP (IN of) (NP (JJ geologic) (NN time)))))) (, ,) (VP (VBG using) (NP (JJ such) (NNS methods)) (PP (IN as) (NP (NN ice-core)))) (CC and) (VP (VBG tree-ring) (NP (NNS studies)))))) (. .)))
This work often involves tracing patterns of atmospheric CO 2 concentrations over very long spans of geologic time, using such methods as ice-core and tree-ring studies.
(ROOT (S (SBAR (WHADVP (WRB How)) (S (NP (NN ice) (NNS cores)) (VP (VBP are) (ADJP (JJ important) (PP (TO to) (NP (NP (DT the) (NN study)) (PP (IN of) (NP (JJ geologic) (NN history))))))))) (VP (VBZ is) (ADVP (RBS best)) (VP (VBN described) (SBAR (IN as) (S (NP (PRP they)) (VP (VBP contain) (NP (NN evidence) (NN showing) (NNS changes)) (PP (IN in) (NP (NP (DT the) (JJ atmospheric) (NN composition)) (PP (IN over) (NP (NN time)))))))))) (. .)))