Crystallinity of wood and the size of cellulose crystallites in Norway spruce (Picea abies)

X-ray diffraction was used to study variations in the crystallinity of wood and the average thickness and length of the crystallites of cellulose as a function of the number of the year ring in Norway spruce [Picea abies (L.) Karst.]. The crystallinity increased from ring 4 to ring 10 from the pith and was constant after ring 10. The crystallinity of mature wood was about 30% +/- 5%. The average thickness and average length of the crystallites were 3.2 +/- 0.1 nm and 28 +/- 2 nm, respectively; and no systematic variation of these values with the number of the year ring was observed. The mean microfibril angle decreased near the pith but was constant in the mature wood.