SOME ANATOMICAL FEATURES OF AN ACACIA HYBRID, A. MANGIUM and A. AURICULIFORMIS GROWN IN INDONESIA WITH REGARD TO PULP YIELD AND PAPER strength

The objectives of this study were to compare anatomical wood properties, chemical composition and wood density between an Acacia hybrid and its parents, namely, Acacia mangium and Acacia auriculiformis. The strength of the relationship between these anatomical properties or wood density and chemical composition as a way to predict the pulp yield and paper strength was studied. Three seven-year-old trees per species were randomly selected from an experimental plantation. Compared with both parents, the Acacia hybrid had longer fibre, and higher slenderness ratio, fibre proportion and holocellulose content but smaller proportions of vessels, parenchyma cells and extractives. In addition, the hybrid tended to have thinner cell wall, and lower proportion of ray cells, rigidity and lignin content but higher flexibility coefficient and wood density than A. mangium. Holocellulose, α-cellulose and lignin contents were all reliably predicted by fibre length. Slenderness ratio was a better predictor of extractives content than fibre length. Both fibre length and slenderness ratio were better predictors of chemical composition than wood density. Therefore, fibre length and slenderness ratio could be good predictors of pulp yield and paper strength for acacias.