( ( ( ( ( ( Hydraulic fracturing ) ( -LRB- ( fracking -RRB- ) ) ) ( has ( been ( ( carried out ) ( in ( ( New Zealand ) ( for ( over ( 23 years ) ) ) ) ) ) ) ) ) but ) ( concerns ( have ( been ( raised ( by ( environmentalists ( about ( its ( negative effects ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (JJ Hydraulic) (NN fracturing)) (PRN (-LRB- -LRB-) (NP (NN fracking)) (-RRB- -RRB-))) (VP (VBZ has) (VP (VBN been) (VP (VBN carried) (PRT (RP out)) (PP (IN in) (NP (NP (NNP New) (NNP Zealand)) (PP (IN for) (NP (IN over) (CD 23) (NNS years))))))))) (CC but) (S (NP (NNS concerns)) (VP (VBP have) (VP (VBN been) (VP (VBN raised) (PP (IN by) (NP (NP (NNS environmentalists)) (PP (IN about) (NP (PRP$ its) (JJ negative) (NNS effects))))))))) (. .)))
Hydraulic fracturing (fracking) has been carried out in New Zealand for over 23 years but concerns have been raised by environmentalists about its negative effects.
(ROOT (S (NP (NNP Fracking)) (VP (VBZ is) (NP (NP (DT another) (NN term)) (PP (IN for) (NP (JJ hydraulic) (NN fracturing))))) (. .)))