Anatomy of Collapse in Eucalyptus Species

Scanning electron microscopy was employed to examine the anatomy of collapse in Eucalyptus bancroftii, E. macrorhyncha, E. nitens, E. oreades, and E. pilularis. Collapse appeared to be restricted to fibres, although other cell types sometimes distorted in response to the stresses developed. The propensity for individual fibres to collapse was not always related to the ratio of wall thickness to lumen diameter, and a complex of factors, e.g. proximity to other cell types, may be involved. Collapse, which was most prevalent in the tangential direction, was rarely accompanied by detectable damage to the wall structure, suggesting that the strength of affected timber should not be seriously diminished.