Studies were carried out for 90 days on the degradation of wood wastes of four economically important Nigerian trees; Terminalia superba, Mansonia altissima, Holoptelia grandis and Milicia excelsa by white rot fungus, Pleurotus tuber-regium a Nigerian edible mushroom. The pH of the wastes dropped to 4.0/4.2, 90 days after incubation. On the contrary, amino nitrogen content of the wastes increased consistently during this period of solid-state fermentation. Lignin degradation also increased with the increase in incubation days. The greatest lignin reduction was observed in H. grandis followed by T superba, M. altissima and M. excelsa. Digestibility of spent substrates by ruminants increased during fermentation as follows: M. excelsa > M. altissima > T superba > H. grandis. These results are discussed in relation to the use of fermented wood wastes as feeds for ruminants. (c) 2007 Elsevier Ltd. All rights reserved.