Abstract:
Fractal theory was first introduced into the description for ultrastructure of wood cell wall in this study. The variability of the fractal dimensions(D)values of the nanofibril in wood cell wall in both radial and tangential directions was studied by taking the mean microfibril angles θ in S2 layer of the wood cell wall determined by polarized light microscopy as the principle parameter. The results showed that the D values in radial direction of the samples close to the pith were the maximum, which declined in a wavy pattern toward the bark direction from the quick descent to slow descent stages. The variation of D values in tangential direction was not obvious, there were no distinct stage characteristics in the wavy descending course.