The amount of oversized straw fibre bundles or shives varied
slightly between the different trials. The shive weight was
in the range of 15–19%. Similar results were obtained by using
the Pulmac instrument (0.15mm slot, Table 4). Defibration of
straw materials will always result in high levels of dust and
oversized fibre bundles compared to wood-based materials.
The geometry of the shives in wheat straw differs from that in
wood-based species. Straw shives have a more compact and
flat structure that is related to the thin outer layer of the straw.
It is assumed that the flat shives consist of a relatively high
amount of fibre bundles that could yield high tensile strength.
However, it is unknown whether the wheat straw shives have
any dramatic effect on other mechanical properties.