The uniaxial natural fabric from the tree Hildegardia populifolia was treated with 5% aqueous NaOH solution for 0, 2, 4, 6, and 8 h, and the resulting changes were analyzed by density, Fourier infrared spectroscopic, X-ray, polarized microscopic, and scanning electron microscopic techniques. On alkali treatment, absorption of water and elimination of hemicellulose in the fabric were observed. In each case, the tensile strength, modulus, and percent elongation at break were determined. The tensile strength, modulus, and density were found to be maximum at 4 h of alkali treatment. Hemicellulose was found on the surface of the untreated fabric. After 6 and 8 h of alkali treatment, some microcracks developed in the fabric. The area of the void region in the fabric increased with the duration of alkali treatment. (C) 2003 Wiley Periodicals, Inc.