Variation in Wood Properties ofEucalyptus nitensin a Provenance Trial on the Eastern Transvaal Highveld in South Africa

Abstract

SYNOPSIS Eucalyptus nitens is one of the four important cold-tolerant eucalypts grown for mining timber and pulpwood on the eastern Transvaal highveld in South Africa. In 1983 an active genetic improvement programme was initiated to improve growth rate, stem form and wood quality of this species. The most important wood properties that influence wood quality are splitting, collapse, and density. Little is known about the amount of variation and the magnitude of correlations between these wood properties. An eleven-year-old provenance trial of E. nitens was chosen for an investigation into the between- and within-tree variation and correlations between density, moisture content, spirality, percentage heartwood, taper, collapse, and splitting. Results from this study indicated large between- and within-tree variation for many of the wood properties measured. Seedlot differences were only detected for density, moisture content, percentage heartwood, and collapse. Density and taper generally increased with in...