( ( A saprotroph ) ( ( ( feeds ( on ( any ( remaining ( organic matter ) ) ) ) ) ( after ( ( other decomposers ) ( do ( their work ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN saprotroph)) (VP (VBZ feeds) (PP (IN on) (NP (DT any) (JJ remaining) (JJ organic) (NN matter))) (SBAR (IN after) (S (NP (JJ other) (NNS decomposers)) (VP (VBP do) (NP (PRP$ their) (NN work)))))) (. .)))
A  saprotroph feeds on any remaining organic matter after other decomposers do their work.
(ROOT (S (NP (NNS Saprotrophs)) (VP (VBP are) (ADJP (JJ decomposers) (SBAR (IN that) (S (NP (NP (NN feed)) (PP (IN on) (NP (DT the) (JJ organic) (NN matter)))) (VP (VBD left) (PRT (RP over)) (PP (IN from) (NP (JJ other) (NNS decomposers)))))))) (. .)))