Review: The value of wood extractives from Pinus radiata

The wood extractives from softwood species, which include resin acids, fatty acids and triglycerides, have useful properties making them valuable as natural products. Their water repellency, adhesive properties and biological activity make them useful in manufacturing, agriculture and medicine with broader applications expected to be developed in the future with a shift toward renewable resources. These wood extractives can be problematic in paper manufacture as they cause deposits on machinery and in the paper products, which requires higher levels of maintenance, limits water recycling, increases wastewater toxicity and can reduce product quality. Current methods for addressing these problems in thermo-mechanical pulp (TMP) and paper mills include treatment of wood to reduce extractives content prior to pulping, tighter control of processes to prevent formation of deposits, and the use of additives to fix extractives into the paper product. Recovery of the wood extractives from the process water in a reasonably pure form would provide new value-added products turning a once troublesome material into something of value for existing pulp and paper mills.