Oud: agarwood, the resin a tree makes against infection

Where does oud come from?

Oud comes from trees of South and Southeast Asia, mainly the genus Aquilaria. Wikipedia's agarwood article explains that healthy heartwood is pale and almost scentless; after infection by the mould Phaeoacremonium parasitica, the tree secretes a defensive resin and the wood turns dense, dark and saturated. "Oud" is the Arabic word for the material, literally "stick". In natural forests only about 7 trees in 100 of the same species become infected.

The oil is steam-distilled from the resinous wood, and the yield is tiny: 70 kg of wood gives no more than 20 ml of oil. The wood is also sold as chips and powder for burning.

What does oud smell like?

Oud has a complex smell with few natural analogues: sweet, woody and balsamic, with leathery, smoky, tobacco-like, animal and fruity facets, and something reminiscent of sandalwood. Burned as incense, it gives a sweet balsamic smoke with shades of vanilla, musk and amber.

What does oud do in a perfume?

Oud is usually a base note, traditionally paired with rose. Few houses use real oud because it is expensive and potent, so most fragrances labelled "oud" are built around an accord. Oud belongs to the woody family with sandalwood and cedarwood.

What should you know about oud?

Agarwood trees are protected under CITES: Aquilaria malaccensis has been listed in Appendix II since 1995, and all Aquilaria species were added in 2004. Wikipedia's Aquilaria malaccensis page gives the species' IUCN status as critically endangered. Adulteration is common, and plantations rely on fungal inoculation with mixed results. If you want the full picture, our class on precious woods covers why these materials are becoming scarce.