Within-tree variation in wood fibre biometry and basic density of the urograndis eucalypt hybrid (Eucalyptus grandis x E. urophylla).

摘要

Within-tree variations in fibre length, width, wall thickness and wood basic density of Eucalyptus grandis x E. urophylla (urograndis) were studied in five 6.8-year-old and five 5.6-year-old trees from one clone in Brazil. Samples were taken at 5, 25, 35, 55, 65 and 90% of stem height and five radial positions (10, 30, 50, 70 and 90% of radius). The tree average fibre length, width and wall thickness of seed and clone trees was 0.955 mm and 1.064 mm, 18 micro m and 20 micro m, 3.6 micro m and 4.4 micro m, respectively. The axial variation of fibre dimensions was very low, while there was a consistent but small increasing trend from pith to periphery. The basic density ranged from 397-464 kg/m3 to 486-495 kg/m3 in seedling and clone trees, respectively, with a low variation along the stem. In comparison with other eucalypt pulpwood such as E. globulus, the urograndis hybrid showed similar fibre dimensions and lower basic density. Overall, the within-tree variation of these wood properties was low and age had a small impact on the variation of density and fibre dimensions..