ORIGINAL PAPER Cellulose microfibril angles and cell-wall polymers in different wood types of Pinus radiata Maree Brennan • J. Paul McLean • Clemens M. Altaner • John Ralph • Philip J. Harris Received: 24 November 2011 / Accepted: 17 March 2012 / Published online: 10 April 2012 Ó Springer Science+Business Media B.V. 2012 Abstract Four corewood types were examined from sapling trees of two clones of Pinus radiata grown in a glasshouse. Trees were grown either straight to produce normal corewood, tilted at 45° from the vertical to produce opposite corewood and compres- sion corewood, or rocked to produce flexure corewood. Mean cellulose microfibril angle of tracheid walls was estimated by X-ray diffraction and longitudinal swell- ing measured between an oven dry and moisture saturated state. Lignin and acetyl contents of the woods were measured and the monosaccharide compositions of the cell-wall polysaccharides determined. Finely milled wood was analysed using solution-state 2D NMR spectroscopy of gels from finely milled wood in DMSO-d 6 /pyridine-d 5 . Although there was no signif- icant difference in cellulose microfibril angle among the corewood types, compression corewood had the highest longitudinal swelling. A lignin content [ 32 % and a galactosyl residue content [ 6 % clearly divided severe compression corewood from the other core- wood types. Relationships could be drawn between lignin content and longitudinal swelling, and between galactosyl residue content and longitudinal swelling. The 2D NMR spectra showed that the presence of H-units in lignin was exclusive to compression core- wood, which also had a higher (1 ? 4)-b-D-galactan content, defining a unique composition for that core- wood type. Keywords Cellulose microfibril angle (MFA)  (1 ? 4)-b-Galactans  2D NMR spectroscopy  Compression wood  Flexure wood  H-units in lignin Introduction The function of wood in a living tree is to conduct water and provide mechanical support. Depending on the structural requirements of trees, wood types with different mechanical properties, anatomies, and M. Brennan  J. P. McLean  C. M. Altaner  P. J. Harris (&) School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand e-mail: p.harris@auckland.ac.nz Present Address: J. P. McLean Forest Products Research Institute, Edinburgh Napier University, Merchiston Campus, Edinburgh EH105DT, Scotland, UK Present Address: C. M. Altaner New Zealand School of Forestry, The University of Canterbury, Private Bag 4800, Christchurch, New Zealand J. Ralph Department of Biochemistry, DOE Great Lakes Bioenergy Research Center, Wisconsin Bioenergy Initiative, Madison, WI, USA J. Ralph Department of Biological Systems Engineering, University of Wisconsin, Madison, WI 53706, USA 123 Cellulose (2012) 19:1385–1404 DOI 10.1007/s10570-012-9697-1