EFFECT OF LOG STEAMING ON THE REDUCTION OF DEFECTS ASSOCIATED WITH GROWTH STRESS OF Eucalyptus grandis
DOI:
https://doi.org/10.5902/198050981880Keywords:
Eucalyptus grandis, growth stresses, log steaming, sawing process.Abstract
The present study was carried out to evaluate log steaming effect on the reduction of defects associated with residual growth stress of Eucalyptus grandis wood. There were used logs with diameter of 20 to <25, 25 to <30 and 30 to <35 cm, from the Horto Florestal, Manduri, São Paulo. Half of the logs was steamed during 20 hours at 90ºC of temperature and 100% of relative humidity. Subsequently, the logs were live sawn and the defects resulting from the growth stresses in logs of various diameter were measured. The results indicate that log steaming provided the release of a great part of the growth stresses, without eliminating them completely, showing, nevertheless, that this treatment is feasible and advisable for growth stress relief; the boards coming from heated logs of 20 to <25 cm presented, in general, larger defect reduction, showing that the smaller the log diameter the higher the efficiency of steam treatment at 90ºC of temperature during 20 hours.
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ACOSTA, M.S. Experiência argentina en la producción y utilización de la madera de eucalipto, Panorama a 1999. In: WORKSHOP: TECNICAS DE ABATE, PROCESSAMENTO E UTILIZAÇÃO DA MADEIRA DE EUCALIPTO, 1999, Viçosa. Anais... Viçosa: UFV/DEF/SIF/IEF, 1999. p. 28-38.
BOYD, J.D. The growth stresses: evidence of a origin in differentiation and lignification. Wood Science and Technology, v. 6, p. 251-262, 1972.
CHAFE, S. C. Growth stresses in trees. Australian Forrest Research, v. 9, n. 3, p. 203-223, 1979.
USDA – UNITED STATES DEPARTMENT OF AGRICULTURE. Wood handbook : wood as an engineering material. Madison: U.S. Department of Agriculture, 1999. 463p.
GARCIA, J.N. Técnicas de desdobro de eucalipto. In: SEMINÁRIO INTERNACIONAL DE UTILIZAÇÃO DA MADEIRA DE EUCALIPTO PARA SERRARIA, 1995, São Paulo. Anais... Piracicaba: Instituto de Pesquisa e Estudos Florestais/ Instituto de Pesquisas Tecnológicas, 1995. p. 59-67.
KUBLER, H. Growth stresses in trees and related wood properties. Forest Products Abstracts. Farnham Royal, v. 10, n. 3, p. 61-119, 1987.
MACKAY, J.F.G. Influence of steaming on water vapor diffusion in hardwoods. Wood Science, v. 3, p. 156-160, 1971.
MONTAGNA, R.G.; PONCE, R.H.; FERNANDES, P.S.; RIBAS, C. Desdobro de Eucalyptus grandis Hill ex Maiden visando a diminuir o efeito das tensões de crescimento. Revista do Instituto Florestal, v. 3, n. 2, p. 181-190, 1991.
NICHOLSON, J.E. Growth stresses differences in eucalypts. Forest Science, v. 9, n. 3, p. 169-174, 1973.
ROZAS MELLADO, E.C.E. Contribuição ao desenvolvimento tecnológico para a utilização de madeira serrada de Eucalyptus grandis (Hill Ex Maiden) na geração de produtos com maior valor agregado. 1993. 133p. Dissertação (Mestrado em Engenharia Florestal) – Universidade Federal do Paraná, Curitiba, 1993.
SALES, C.G. Growth stresses: main results obtained on the study of guyana species and consequences for and use. In: IUFRO WORLD CONGRESS, 18, Ljubljana, 1986. Proceedings… Ljubljana: IUFRO, 1986. v. 5, p. 234-248.
SEVERO, E.T.D.; TOMASELLI, I. Efeito da vaporização no alívio das tensões de crescimento em toras de duas procedências de Eucalyptus dunnii. Sciencia Agraria, v. 1, n. 1-2, p. 29-32, 2000.
SIMPSON, W.T. Effect of steaming on the drying rate of several species of wood. Wood Science, v. 7, p. 247-255, 1975.
SKOLMEN, R. G. Heating Logs To Relieve Growth Stresses. Forest Products Journal, v. 17, p. 41-42, 1967.
STEINHAGEN, H. P; MEYERS,G.E.; KUBLER,H. Heating times charts for frozen and nonfrozen veneer logs. Forest Products Journal, v. 30, n. 4, p. 27-37, 1980.
TEJADA, A.; OKUYAMA, T.; YAMAMOTO, H.; YOSHIDA, M. Reduction of growth stress in logs by direct heat treatment: assessment of a commercial-scale operation. Forest Products Journal,, v. 47, n. 9, p. 86-93, 1997.
UMAÑA, C.L.A.; BRITO, E.O. Avaliação de tempos de cozimento de toras de três espécies florestais utilizadas na fabricação de lâminas de madeira. In: CONGRESSO INTERNACIONAL DE COMPENSADO E MADEIRA TROPICAL, 5., 2003, Pará. Anais... Pará: CDP, 2003. s.p.
WEIK, B.B.; WENGERT, E.M.; SCHOREDER, J.; BRISBIN, R.. Practical drying techniques for yellow-poplar S-D-R fliches. Forest Products Journal, v. 34, p. 39-44, 1984.
WILKINS, A.P. Nature and origin of growth stresses in trees. Australian Forestry, v. 49, n. 1, p. 56-62, 1986.
