( ( This study ) ( ( investigates ( ( ( the ability ) ( of ( ( seven species ) ( of ( plant-parasitic nematodes ) ) ) ) ) ( to ( attack ( seedlings ( of ( both ( tree species ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN study)) (VP (VBZ investigates) (S (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (NP (CD seven) (NNS species)) (PP (IN of) (NP (JJ plant-parasitic) (NNS nematodes)))))) (VP (TO to) (VP (VB attack) (NP (NP (NNS seedlings)) (PP (IN of) (NP (DT both) (NN tree) (NN species)))))))) (. .)))
This study investigates the ability of seven species of plant-parasitic nematodes to attack seedlings of both tree species.
(ROOT (S (NP (NNS Nematodes)) (VP (MD can) (VP (VB be) (NP (NP (DT a) (NN parasite)) (PP (IN of) (NP (DT both)))))) (. .)))
Nematodes can be a parasite of both.