Within-Tree Variation of Heartwood, Extractives and Wood Density in the Eucalypt Hybrid Urograndis (<i>Eucalyptus Grandis × E. Urophylla</i>)
Keywords:Heartwood, extractives, wood density, eucalypt hybrid, urograndis, <i>Eucalyptus grandis × E. urophylla</i>
AbstractThe within-tree variation of heartwood content and the accumulation of extractives were studied in the eucalypt hybrid urograndis (Eucalyptus grandis X E. urophylla) in five 5.6-year-old trees from one clone in a commercial pulpwood plantation in Brazil. Wood basic density was on average 0.491 g/cm-3 and with a small axial variation. Heartwood was present in all the trees up to 65% of total tree height, amounting to 38.8% of the total volume. Within the tree, heartwood decreased from the base upwards, on average representing 51%, 44%, 39%, 32%, and 19% of cross-sectional area at, respectively, 5%, 25%, 35%, 55%, and 65% of total tree height, with a very small between-tree variation. The extractives content of heartwood was double that of sapwood (7.6% vs. 3.7%). The extractives were mostly ethanol and water solubles that showed a trend of decreasing content along the stem from base upwards. Heartwood is a quantitative significant quality parameter in the wood of the urograndis eucalypt hybrid, and its inclusion in selection programs is suggested.
Bamber, R. K., and K. Fukazawa. 1985. Sapwood and heartwood. A review. Forestry Abstr.46:567-580.nBhat, K. M., K. V. Bhat, and T. K. Dhamodaran. 1990. Wood density and fiber length of Eucalyptus grandis grown in Kerala, India. Wood Fiber Sci.22:54-61.nGominho, J., and H. Pereira. 2000. Variability of heartwood content in plantation grown Eucalyptus globulus Labill. Wood Fiber Sci.32:189-195.nHiggins, H. G. 1984. Pulp and paper. Pages 290-316 in W. E. Hillis and A. G. Brown, eds. Eucalyptus for wood production. CSIRO/Academic Press, Melbourne, Australia.nHillis, W. E. 1962. Wood extractives and their significance to the pulp and paper industries. Academic Press, New York, NY. 513 pp.nHillis, W. E. 1972. Properties of eucalypt woods of importance to the pulp and paper industries. Appita26:113-122.nHillis, W. E. 1987. Heartwood and tree exudates. Springer-Verlag, Berlin, Germany. 268 pp.nWilkes, J. 1984. The influence of rate of growth on density and heartwood extractives content of eucalypt species. Wood Sci. Technol.18:113-120.nWilkes, J. 1988. Variations in wood anatomy within species of eucalypts. IAWA Bull. n.s.9:13-23.nWilkins, A. P. 1991. Sapwood, heartwood and bark thickness of silviculturally treated Eucalyptus grandis.Wood Sci. Technol.25:415-423.n
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