You might be shocked to know this—something as exotically fragrant as Agarwood or Oudh is actually a result of the plant’s defense mechanism against bacterial or fungal attacks! Yes, the Oudh tree is prone to being infected by a parasitic mould. The tree, in response to this infection, exudes a protective lubricant, a thick resin. This aromatic resin is found in different wounded parts of the tree including its trunk, branches and roots. During this reaction, the wood gradually darkens, changing from lighter to darker shades of brown, often turning black. This is why Agarwood bark chips are so dark in color. Some purists say that the darker shade is a mark of purity while other give more importance to strength of the fragrance.
Agarwood harvesters know that in order to extract the potent Agarwood resin, they need to nurture this defense mechanism, i.e. the infestation, but to a degree that the tree is not permanently damaged. In Agarwood trees, the infection can spread across the sapwood and heartwood. Seasoned Agarwood cultivators know how to spot the infected parts of the tree, i.e. parts that contain the precious resin and are not overwhelmed by the microbial attack.
The resin collected by the harvester has to be put through a distillation process. The traditional water distillation process is still the most preferred way of obtaining the oil. Depending upon the harvesting and extraction expertise used, an Agarwood harvester will offer different options of the scented wood. This involves the oil that is valued highly for its concentrated woody aroma, followed by chips of the bark itself, and powder. Agarwood oil is also called Oudh oil or Oud.