A major problem in the strength data available for cellulose fibre-based materials is that the moisture content of the test specimens is rarely measured, and yet it is the dominant variable in the tests. Detailed strength and stiffness results are presented for Brazilian Dendrocalamus Giganteus bamboo at a wide range of moisture contents down to 2% and the fatigue curve is given for Chinese Moso bamboo at 4% moisture content. Techniques are described for handling the variability of these natural materials, both in design and in manufacturing quality control, for the mass production of large, high-tech composites wind turbine blades.