Wood resin in Acacia Mangium and Acacia crassicarpa wood and knots

The lipophilic extractives, i.e. the wood resin, in Acacia mangium and Acacia crassicarpa stemwood and knots were analysed. A mangium stemwood contained over 1% hexane-soluble extractives, whereas A. crassicarpa contained only 0.1 to 0.2%. The amount of lipophilic extractives was on the same level in stem heartwood and sapwood, while knots contained smaller amounts. Long-chain saturated fatty acids and alcohols, with 22 to 28 carbon atoms make up the major part of the extractives in A. mangium. A crassicarpa contains mainly short-chain fatty acids with 16 to 20 carbon atoms. It is concluded that special technical measures are required for A. mangium to remove the extractives from the fibres in pulping and bleaching and to keep them in a dissolved or colloidal state in the pulping and bleaching liquors.