An improved fibril angle measurement method for wood fibres

A rapid, reliable technique for the observation and measurement of the fibr il angle in wood cell walls has been developed. Sonication in the presence of solutions of certain cobalt and copper salts (5%, wt/vol) was found to b e most effective in facilitating fibril angle visualisation. Latewood fibre fibril angle, which previously had been difficult to measure, was also vis ible, though less frequently. This method has been successfully applied to a number of softwood species including coastal Douglas-fir whose prominent spiral thickenings make it difficult to determine the fibril angle by other methods. The method was also used to determine the fibril angle of some ha rdwood species as well as a non-woody material, flax straw. It can also be used to determine the microfibril angle of pulp fibres although this proced ure is less convenient than with wood sections.