Determining the Transverse Dimensions of Fibers in Wood Using Confocal Microscopy


  • Ho Fan Jang
  • Rajinder S. Seth
  • Cheng Bao Wu
  • Ben K. Chan


Confocal microscopy, image analysis, cell-wall thickness, fiber dimensions, wood density, wood structure


We describe a technique for determining the transverse dimensions of individual fibers in wood using confocal laser scanning microscopy and image analysis. Optical sectioning of confocal microscopy produces high-quality cross-sectional images of large wood samples, thus eliminating the need for traditional mechanical sectioning and its inherent limitations. The relationships between fiber transverse dimensions of wood and kraft pulp fibers, in terms of their means and distributions, are now established. Measuring fibers in wood also allows us now to evaluate properties of early- and latewood separately, and to better understand the origin of heterogeneity. Relative wood density obtained from a wood section correlates strongly to the ratio of fiber wall thickness to perimeter, which is an important parameter for fiber transverse collapse. This direct and accurate method has the potential for automation, thus allowing a rapid assessment of wood quality for papermaking.


Andrews, E. K. 1986. Impact of fiber morphology and chemical composition on the kraft process and subsequent handsheet properties. Pages 111-119 in Tappi Research and Development Conference Proceedings, TAPPI Press, Atlanta, GA.nChan, B. K., H. F. Jang, and R. S. Seth. 1998. Measurement of fibre wall thickness by confocal microscopy and image analysis. Appita J.51(3):229.nDonaldson, L. A., and M. J. F. Lausberg. 1998. Comparison of conventional transmitted light and confocal microscopy for measuring wood cell dimensions by image analysis. IAWA J.19(3):321-336.nEvans, R., G. M. Downes, D. N. J Menz, and S. L. Stringer. 1995. Rapid measurement of variation in tracheid transverse dimensions in a radiate pine tree. Appita J.48(2):134-138.nEvans, R., R. P. Kibblewhite, and S. L. Stringer. 1997. Kraft pulp fibre property prediction from wood properties in eleven radiate pine clones. Appita J.50(1):25-33.nGee, W. Y., and J. V. Hatton. 1991. Simple method for mass production of discrete kraft pulp samples. Tappi J.74(2):221-222.nJang, H. F. 2001. A theory for the transverse collapse of wood pulp fibres. Pages 193-210 in C. F. Baker, ed. The Science of Papermaking: Transactions of the Twelfth Fundamental Research Symposium held in Oxford, FRC, Bury, UK.nJang, H. F., and R. S. Seth. 1998. Using confocal microscopy to characterize the collapse behavior of fibers. Tappi J.81(5):167-174.nJang, H. F., A. G. Robertson, and R. S. Seth. 1991. Optical sectioning of pulp fibers using confocal scanning laser microscopy. Tappi J. (74)10: 217-219.nJang, H. F., A. G. Robertson, and R. S. Seth. 1992. Transverse dimensions of wood pulp fibres by confocal laser scanning microscopy and image analysis. J. Mater. Sci.27:6391-6400.nKing, J. N., C. Cartwright, J. Hatton, and A. D. Yanchuck. 1998. The potential of improving western hemlock pulp and paper quality. I. Genetic control and interrelationships of wood and fibre traits. Can. J. For. Res.28(6):863-870.nMoÚll, M. K., and L. A. Donaldson. 2001. Comparison of segmentation methods for digital image analysis of confocal microscope images to measure tracheid cell dimensions. IAWA J.22(3):267-288.nMoss, P., I. Nyblom, A. Sneck, and H-K. Hyvärinen. 1999. The location and quantification of lignin in kraft pulps using a confocal laser scanning microscope (CLSM) and image analysis. Pages 221-227 in Proc.: Microscopy as a Tool in Pulp and Paper Research and Development, Stockholm, Sweden.nPotter, S., C. Norris, C. Cartwright, J. King, W. Gee, A. Hussein, M. McRae, S. Pitts, and P. Watson. 2000. Fibre and wood density assessment of western hemlock progeny, Pulp and Paper Report 1492, Paprican, Pointe-Claire, QC, Canada. 23 pp.nScallan, A. M., and H. V. Green. 1975. The effect of pulping upon the dimensions of wood tracheids. Wood Fiber7(3):226-233.nSeth, R. S. 1990. Fibre quality factors in papermaking-II. The importance of fibre coarseness. Pages 143-161 in MRS Symposium Proceedings, Vol. 197, Materials Research Society, Pittsburgh, PA.nSeth, R. S., H. F. Jang, B. K. Chan, and C. B. Wu. 1997. Transverse dimensions of wood pulp fibres and their implications for end use. Pages 473-503 in C.F. Baker, ed. The Fundamentals of Papermaking Materials: Transactions of the Eleventh Fundamental Research Symposium held in Cambridge, Pira International, Leatherhead, UK.nSprent, P. 1993. Applied nonparametric statistical methods, 2nd ed., Chapman and Hall, London. 342 pp.nStehr, M., S. Joachim, and J. Ingvar. 1998. UV laser ablation—An improved method of sample preparation for microscopy. Holzforschung52(1):1-6.nTravis, A. J., D. J. Hirst, and A. Chesson. 1996. Automatic classification of plant cells according to tissue type using anatomical features obtained by the distance transform, Annals Botany78:325-331.nWilliams, G. J., and J. G. Drummond. 2000. Preparation of large sections for the microscopical study of paper structure. J. Pulp Paper Sci.26(5):183-193.n






Research Contributions