Moisture absorption has a softening effect on the bamboo strip as indicated by the consistent increase in breaking strain (Fig. 4a) and decrease in elastic modulus (Fig. 4b). Moisture absorption also caused a small increase to the tensile strength of the bamboo strips, as shown in Fig. 4b. These are in broad agreement with the bending test results on moso bamboo by Chung and Yu [14]. They found that the moisture absorption had no effect on flextural strength. It should be noted that their bending test was conducted on bamboo trunks while our tensile test was done on bamboo strips taken from the high fiber density region of the bamboo trunk. Improved tensile strength of cellulose fibers due to humidification has been reported by other workers. For example, Stamboulis et al. [22] reported that after being humidified at 90% RH, green flax fibers increased their tensile strength by about 20%. They suggested that the availability of some free water molecules had a plasticizing effect which was advantageous to the strength of cellulose fibers.