( They ( ( are ( produced ( by ( asexual reproduction ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBP are) (VP (VBN produced) (PP (IN by) (NP (JJ asexual) (NN reproduction))))) (. .)))
They are produced by asexual reproduction.
(ROOT (S (NP (NNP Trees)) (VP (VBP send) (PRT (RP out)) (NP (NP (JJ rootlike) (NNS extensions)) (SBAR (WHNP (WDT that)) (S (VP (VBP produce) (SBAR (S (NP (JJ new) (NNS stems)) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (JJ asexual) (NN reproduction)))))))))))) (. .)))
Trees send out rootlike extensions that produce new stems is an example of asexual reproduction.