Among-family variations of chemical and Kraft-pulp properties in the heartwood of the third-generation Acacia mangium in Indonesia

Abstract The content of wood chemical components (extractives, ash, Klason lignin, and polysaccharides) and Kraft-pulp properties (yield and kappa number) were directly determined for the inner and outer heartwood of 10-year-old 20 open-pollinated families in the third-generation Acacia mangium in Indonesia. The results show that the extractives, Klason lignin, and α -cellulose contents of outer heartwood were higher than those of inner heartwood. Relatively higher variance components of family were observed for polysaccharides and Kraft-pulp yield. Significant positive phenotypic correlations were found between stem diameter and either basic density or α -cellulose content, as well as between Kraft-pulp yield and α -cellulose content. Meanwhile, significant negative correlations were found between Kraft-pulp yield and organic solvent extracts or Klason lignin. Therefore, it is concluded that families with larger stem diameters and higher α -cellulose contents tend to produce higher pulp yield.