Effect of Botryosphaeria Stem Canker Disease on the Anatomical Structure of <i>Eucalyptus</i> Wood

Eucalyptus clones have been widely planted in Uganda to cope with the increasing demand for wood. However, the newly introduced clones are susceptible to attack by Botryosphaeria canker disease. Canker diseases have been reported to affect wood formation and the kino gum produced also affects the appearance of the wood. The objective of this study was to investigate the effect of Botryosphaeria canker disease on the macro and micro (anatomic) structure of Eucalyptus wood. The macrostructure was analysed using a scanner while the anatomic characteristics of normal and diseased wood were analysed using light microscopy. Both structural and quantitative analysis of cell dimensions were carried out. The macroscopic study revealed that wood gets distorted, discoloured and growth of normal wood gets altered due to fungal infection. Microscopic study revealed that xylem tissue in the diseased wood had significantly fewer number of vessels and more parenchyma cells. The vessels were significantly smaller in diameter and shorter in length than those in healthy wood while the diseased xylem tissue had significantly longer fibres than the normal xylem tissue. The observed changes in the wood structure following attack by Botryosphaeria canker disease is likely to affect the physical and mechanical properties of the wood, hence its utilisation.