Natural Habitat or a 7-Fold Pattern of Phyllotaxis in Eucalyptus Nitens?
by
Irene Lena Hudson
Department of Mathematics and Statistics, University of Canterbury Christchurch NZ
Coauthors: Michelle Dalrymple (Maths and Stats: University of Canterbury)

Eucalyptus nitens (shining gum) and eucalyptus globulus (blue gum) are important sources of fibre for the Australian and NZ paper industry. Eucalypt hardwood cells are the product of physiological and genetic processes starting with the differentiation of the cambium. Factors such as age, growth rate and stresses, site and genotype and size of cambial initials determine wood microstructure and the inherent variability in wood properties.

This is a study of the spatio-temporal variation of fibre morphology using a multivariate clustering and a multivariate nonlinear time series (NLMVTS) approach. We show that the early to latewood variation (ELW), within annual tings, differs across rings and across all sampling heights in E. nitens. ELW variation seems to be governed by cambial age (CA), where CA is related to the time the first vascular cambial cell formed at a given height and ring.

At all sampling heights and in all annual rings in E. nitens, earlywood to latewood (E/LW) segments exhibit specific fibres which can be identified as a repeating permutation of a particular 7 cluster sequence; similar to a repeating DNA sequence. The repeating 7-cluster pattern suggests a 7-fold pattern of phyllotaxis - based on Fibaonacci spirals often found in plants during the process of development from the growing tip.

These results indicate a possibly pseudo cylindrical pattern of whole tree variation in E. nitens showing this species to be slower to react to environment, with less summer-drought slowing of growth than E. globulus, possibly due to its natural habitat.This is in contrast to the significant oblique whole tree variation evidenced in E. globulus (Hudson IL, Dalrymple M, Wilson LF (1999); Biometrics 1999 Hobart).

This paper highlights the importance of understanding the role of cambial physiology and seasonality on whole tree fibre variation. Genetic manipulation, particularly of cambial activity, may provide a means of producing fibres with specific dimensions for given end-uses.

Date received: October 22, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caid-51.