Decomposition of lignin and holocellulose study was conducted in Acacia dealbata Link (Mimosoideae) leaves, twigs and barks from the virgin forest ecosystem of Doddabetta belt of Nilgiris during monsoon period June, July and August 2013. Four lignin and holocellulose degrading fungi which were dominating the A. dealbata forest ecosystem were identified, viz., Creolophus cirhatus, Hirschioporus abietinus, Schizophyllum commune and Stereum rugosum. The spores collected from the fruit bodies / the mycelia from the degrading material were inoculated individually to the experimental leaves, twigs and barks to analyse the decomposition potentials of lignin and holocellulose. The percentage of degradation of lignin, holocellulose and hot water soluble content varied with the samples and as well as the fungal isolates. However the degradation is a long process which certainly adds nutrients to the virgin forest ecosystem.