( Humus ( ( is ( ( the product ) ( of ( ( the decay ) ( of ( ( organic residues ) ( such ( as ( ( ( ( ( wood , ) leaves ) , ) and ) ( other ( biological materials ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Humus)) (VP (VBZ is) (NP (NP (DT the) (NN product)) (PP (IN of) (NP (NP (DT the) (NN decay)) (PP (IN of) (NP (NP (JJ organic) (NNS residues)) (PP (JJ such) (IN as) (NP (NP (NN wood)) (, ,) (NP (NNS leaves)) (, ,) (CC and) (NP (JJ other) (JJ biological) (NNS materials)))))))))) (. .)))
Humus is the product of the decay of organic residues such as wood, leaves, and other biological materials.
(ROOT (S (NP (NP (DT The) (JJ decayed) (NNS remains)) (PP (IN of) (NP (VBG living) (NNS organisms)))) (VP (VBZ is) (VP (VBN called) (NP (NNS humus)))) (. .)))