Wood Property Differences in South African Grown Eucalyptus grandis Trees of Different Growth Stress Intensity

The relationship between level of growth stress and the properties of the wood of Eucalyptus grandis have been investigated. Highand low-stressed trees were sampled from a 27-year-old plantation in the Eastern Transvaal for the purpose of this study. To reduce the incidence of reaction wood only near vertical trees were selected. Marked differences in a number of anatomical features and wood density and their radial Variation were found among trees of widely different growth stress intensities. This result may possibly help to explain the considerable Variation in wood properties often observed among plantation grown trees, for growth stress have been shown to vary considerably among trees. Results also suggest that the selection for reduced level of growth stress in a tree breeding program would, apart from a reduction in Splitting, also result in reduced within-tree variability in wood quality.