W.E. Hillis, R. Evans, R. Washusen
An unusual formation of tension wood in a natural forest Acacia sp.
The determination of microfibril angle (MFA), cellulose
crystallite width and microdensity by SilviScan-2 at CSIRO
confirmed that several dark bands in the heartwood
of an Acacia species were associated with tension wood
(TW) fibres. The straight log was taken from a tree of
about 30 years of age that had been apparently growing
vertically as there were no signs of the usual stimuli for
TW formation. The continuous dark bands of about 5 mm
width extended radially from the inner heartwood in a
spiral pattern and were separated by continuous normal
wood bands of similar width. The TW bands continued
in the sapwood from the heartwood boundary to the
cambium but were not coloured. The dark colour of the
TW was probably caused by extractives being polymerised
at the heartwood boundary by enzymes in the TW
fibres in the sapwood. The MFA and cellulose crystallite
width indicated the TW in a band was of similar intensity
throughout its length, indicating similar microstructural
characteristics at different cambial ages. The initiation of
spiral grain formation occurs before that of tension wood
in the Acacia samples studied.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 58, 05/2004
Pages: 241 - 245
Show full article (external site)
Show all available items of this journal
Search
