The wood properties and sawn board quality of the<i>Eucalyptus grandis</i>x<i>E. urophylla</i>hybrid

SYNOPSIS Up to now only two studies have been carried out in South Africa on the solid wood properties of eucalypt hybrids. In both cases the trees were still too small for processing into sawn boards to assess sawn board quality. This paper reports the results of a sawmilling study which was carried out on E. grandis x E. urophylla with the main objective to compare the quality of the sawn boards produced with those of E. grandis. Apart from wood density, differences in features such as splitting in log ends, and warp, knot characteristics, splitting and brittle heart in sawn boards were small and statistically of no or little significance. All these properties varied considerably between trees. Wood density, on the other hand, differed significantly between the two groups of trees studied. Results indicated that the density of the wood produced by the hybrid could be about 0,70 g/cm3 higher on average than that of E. grandis. Unfortunately, the density of the wood produced by the hybrid was considerably more variable between trees, as well as within trees. This was to be expected, as the hybrid has not yet been subjected to any genetic improvement. An excellent opportunity therefore exists to improve these properties in a genetic improvement programme.

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