INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS

Earlywood, formed at the beginning of the growth period each year in temperate regions, has tracheids that are thinner-walled and larger in diameter than those laid down later in the season, the latewood. As a consequence, the permeability to moisture movement differs, particularly as some of the pi...

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Autores principales:	McCurdy,Murray C, Keey,Roger B
Lenguaje:	English
Publicado:	Universidad del Bío-Bío 2002
Materias:	Softwood Pinus radiata flat-sawn quarter-sawn moisture movement
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2002000100003
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spelling	oai:scielo:S0718-221X20020001000032007-03-22INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDSMcCurdy,Murray CKeey,Roger B Softwood Pinus radiata flat-sawn quarter-sawn moisture movement Earlywood, formed at the beginning of the growth period each year in temperate regions, has tracheids that are thinner-walled and larger in diameter than those laid down later in the season, the latewood. As a consequence, the permeability to moisture movement differs, particularly as some of the pits in the latewood tracheids may close or aspirate. Boards sawn from a log will have the orientation of the growth rings (representing seasonal accumulation of woody material) at various angles to the long dimension of the boards. The extreme cases, known as flat-sawn and quarter-sawn, respectively, represent the situations where the growth rings lie parallel to the long dimension or at right angles to it. Tests were undertaken on the drying behaviour of both flat-sawn and quarter- sawn, 50mm-thick sapwood boards of Pinus radiata dried under so-called high-temperature conditions, 120/70°C, with an air velocity over the boards of 5m s-1 in a single-board drying tunnel. Moisture-content profiles were determined by slicing samples after various stages of drying. In the wet core, the moisture distribution was uniform with quarter-board boards, but showed "peakiness" corresponding to the latewood zones in flat-sawn boards. With either orientation, there is a thin dry layer below fibre saturation at the surface, which in the case of flat-sawn boards is one growth-ring-wide. Quarter-sawn boards dry more slowly than flat-sawn boards due to different drying mechanisms, and these differences in drying behaviour is also reflected in differences in strain development as the wood tries to shrink in conformity with the local moisture contentinfo:eu-repo/semantics/openAccessUniversidad del Bío-BíoMaderas. Ciencia y tecnología v.4 n.1 20022002-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2002000100003en10.4067/S0718-221X2002000100003
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Softwood Pinus radiata flat-sawn quarter-sawn moisture movement
spellingShingle	Softwood Pinus radiata flat-sawn quarter-sawn moisture movement McCurdy,Murray C Keey,Roger B INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS
description	Earlywood, formed at the beginning of the growth period each year in temperate regions, has tracheids that are thinner-walled and larger in diameter than those laid down later in the season, the latewood. As a consequence, the permeability to moisture movement differs, particularly as some of the pits in the latewood tracheids may close or aspirate. Boards sawn from a log will have the orientation of the growth rings (representing seasonal accumulation of woody material) at various angles to the long dimension of the boards. The extreme cases, known as flat-sawn and quarter-sawn, respectively, represent the situations where the growth rings lie parallel to the long dimension or at right angles to it. Tests were undertaken on the drying behaviour of both flat-sawn and quarter- sawn, 50mm-thick sapwood boards of Pinus radiata dried under so-called high-temperature conditions, 120/70°C, with an air velocity over the boards of 5m s-1 in a single-board drying tunnel. Moisture-content profiles were determined by slicing samples after various stages of drying. In the wet core, the moisture distribution was uniform with quarter-board boards, but showed "peakiness" corresponding to the latewood zones in flat-sawn boards. With either orientation, there is a thin dry layer below fibre saturation at the surface, which in the case of flat-sawn boards is one growth-ring-wide. Quarter-sawn boards dry more slowly than flat-sawn boards due to different drying mechanisms, and these differences in drying behaviour is also reflected in differences in strain development as the wood tries to shrink in conformity with the local moisture content
author	McCurdy,Murray C Keey,Roger B
author_facet	McCurdy,Murray C Keey,Roger B
author_sort	McCurdy,Murray C
title	INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS
title_short	INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS
title_full	INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS
title_fullStr	INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS
title_full_unstemmed	INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS
title_sort	influence of sawing orientation on moisture movement through softwood boards
publisher	Universidad del Bío-Bío
publishDate	2002
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2002000100003
work_keys_str_mv	AT mccurdymurrayc influenceofsawingorientationonmoisturemovementthroughsoftwoodboards AT keeyrogerb influenceofsawingorientationonmoisturemovementthroughsoftwoodboards
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INFLUENCE OF SAWING ORIENTATION ON MOISTURE MOVEMENT THROUGH SOFTWOOD BOARDS

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