Lignocellulosic biomass which is rich in cellulose and hemicellulose can be used in submerged fermentation for the production of industrially important enzyme i.e., cellulase. The present work deals with standardization of pretreatments of forestry waste for enhancing the suitability of this abundant waste for cellulase production. Among different pretreatments alkali peroxide pretreatment to Populus deltoides has emerged as a cost effective substrate for cellulase production by Bacillus stratosphericus N12 (M) yielded maximum cellulase activity of 41.73 U/g. The maximum cellulase production for pretreated P. deltoides was carried out in the PYC, pH of the medium was 8 and incubated at 30oC for the production and incubation period of 72 h and partial purification of cellulase was done by ammonium sulphate precipitation method leads to increased cellulase activity. It has also been noticed that though forest lignocellulosics when used as carbon source yielded fairly good amount of cellulase but its production is directly dependent upon type of biomass used versus physicochemical treatment given to it prior to biodegradation.