What is agarwood?

Agarwood is a dark, resin infused wood that forms inside certain tropical trees after they are wounded or infected. The resin is what people are actually after. It is intensely fragrant, and it is the reason the highest grades are often said to be worth more than their weight in gold.

Most trees never produce it at all. The ones that do are species in the genus Aquilaria, and to a lesser extent Gyrinops, native to the forests of South and Southeast Asia, southern China and New Guinea. Healthy heartwood from these trees is pale, light and largely odourless. It is only after the tree suffers some kind of injury, whether from a storm, an animal, an insect or a fungal infection, that the transformation begins. The tree responds the way many plants do, by producing a defensive resin meant to seal the wound and resist the spread of infection. In Aquilaria and Gyrinops trees, that resin happens to be aromatic, dense and dark. Over months or years it saturates the surrounding wood fibres, and what was once plain timber becomes agarwood.

This is why agarwood cannot simply be planted and harvested like most timber. The tree has to be hurt first, and then it has to be given time, often many years, for the resin to develop and spread through the wood. Wild trees that survive an injury and slowly resinate over decades are the source of the rarest and most expensive material. Plantation growers have developed ways to deliberately wound or inoculate trees to speed the process along, but even induced resin formation still takes years, not weeks.

Two genera, not one species

Agarwood is not produced by a single tree. Aquilaria is the larger of the two genera, with about 21 recognised species ranging from northeastern India and Bangladesh through southern China, Vietnam, Cambodia, Laos, Thailand, Malaysia, the Philippines and Indonesia to New Guinea. Because Aquilaria trees are generally reported to grow faster than their Gyrinops relatives, they are the trees of choice for most commercial plantations, including the large operations now common in Vietnam and Indonesia.

Gyrinops is a smaller genus of around nine species. Most grow further east, in eastern Indonesia and New Guinea, with one species, Gyrinops walla, found in Sri Lanka and southern India. Gyrinops grows more slowly than Aquilaria, which has made it less attractive for large plantations and harder to study in the wild, since its natural range is more remote. Even so, its resin is valued by many traders and is increasingly part of the legal plantation supply from eastern Indonesia.

Both genera belong to the same plant family, Thymelaeaceae, and both were brought under CITES protection at the same time. They are genetically distinct, though, and resin character can vary meaningfully between them. The differences between species and growing regions are covered in our guide to Aquilaria vs Gyrinops and the wider Origins & Varieties hub.

How agarwood forms

The mechanism behind agarwood formation has been studied closely by botanists and chemists, and the broad picture is well established. When an Aquilaria tree is wounded, whether by mechanical damage or by fungal colonisation, it triggers a cascade of biochemical defence responses. Researchers have identified two groups of compounds at the centre of this process, sesquiterpenes and 2-(2-phenylethyl)chromones, both of which accumulate at the site of injury and give agarwood its distinctive scent. Fungal infection appears to play an especially significant role, with certain fungi shown to trigger or accelerate resin production as part of the tree's defence against the infection itself.

The result is heartwood that has changed in both appearance and composition. Where uninfected wood is light and fairly uniform, resin infused agarwood develops dark, often blackened streaks and patches, sometimes across the whole piece if saturation is high enough. Collectors and traders often describe high resin pieces as feeling slightly oily or waxy rather than dry like ordinary wood, and as carrying a faint scent even before burning. That scent is often described as something between woodsmoke and dried fruit, though individual pieces vary considerably and scent description is inherently subjective. The wood becomes denser too.

Sinking is one of the oldest rough tests traders use, though it is a signal rather than proof, since wood can be weighted or soaked to sink. The property also gave agarwood several of its names across Asia, which translate to "sinking incense." Our guide on resin content explains what the test can and cannot tell you, and how agarwood resin forms covers the science in more depth.

Agarwood the wood, oud the oil

One source of confusion for new buyers is the relationship between agarwood and oud. In most of the world, oud and agarwood refer to the same raw material, the resin infused wood itself, and the terms are used interchangeably depending on the language. It gets more specific in Western retail and perfumery, where "oud oil" refers to a product made from agarwood rather than the wood itself.

Oud oil is made by soaking agarwood and then distilling it, usually with water or steam, to extract the aromatic compounds into an oil. That oil is worn directly on the skin, used in attars across the Middle East and South Asia, and appears in perfumery. Many modern perfumes labelled with an oud note use a synthetic oud accord instead of the natural oil. Agarwood chips and oud oil are different formats of the same underlying resin, suited to different uses, and the choice between them is largely a matter of preference rather than one being more authentic than the other.

Its many names

Agarwood goes by a long list of names, and none of them tells you anything about quality or origin on its own. They are simply what different cultures and trade languages have called the same resinous wood for centuries.

None of these names refers to a different species or a different grade. They are linguistic variations for the same material, although the trade customs, grading systems and preferred styles of use do vary considerably from one region to another. Those differences are covered in our regional agarwood comparison.

Why it is so expensive

Several factors combine to make high grade agarwood one of the most expensive natural materials traded by weight, with top quality wild material reported to sell for tens of thousands of dollars per kilogram. Formation is slow and depends on chance injury or deliberate, time intensive inoculation. Not every tree produces resin even after wounding, and the amount of standing tree stock is not the same as the amount of usable resin it will yield. Wild agarwood, where a tree has resinated naturally over years or decades, is considered by many in the trade to be the most prized and commands the steepest prices. Plantation agarwood, produced through deliberate induction, has become an increasingly significant share of the legal global supply.

Conservation pressure adds another layer of cost. Because of high demand and a history of overharvesting, Aquilaria malaccensis was listed in Appendix II of CITES, the international convention regulating trade in threatened species, at its 1994 conference, with the listing in force from 1995. At the 2004 conference, the listing was extended to every species in the genera Aquilaria and Gyrinops, taking effect in January 2005. An Appendix II listing does not ban trade. It means international shipments of agarwood and its products generally need export permits showing the material was obtained legally and without harming the survival of the species. That adds cost and friction to legitimate trade, and leaves room for undocumented or mislabelled material to circulate, a problem covered in our guide to fake oud. Price itself is covered in full in why is agarwood so expensive?

Religious and cultural tradition

Long before agarwood became a global commodity, it held, and still holds, deep spiritual and ceremonial significance across several traditions, often independently of one another.

In Islamic tradition, oud is widely burned as incense and worn as oil, particularly across the Gulf, where it is closely associated with hospitality, personal grooming and religious occasions including Friday prayers and Eid. In Buddhist practice, agarwood incense has long been used in temple ceremonies and meditation, valued for a fragrance considered by many practitioners to support a calm and focused state of mind. Hindu tradition refers to agarwood as agaru in both ceremonial and Ayurvedic contexts. In China, chénxiāng has a documented history of well over a thousand years, used in temple incense, traditional medicine and the literati incense culture that prized rare and complex fragrances as a mark of refinement.

Japan developed its own formalised incense practice, kōdō, which had taken shape as a structured art by the sixteenth century. Rather than simply smelling the incense, practitioners describe the central activity as "listening" to the scent, a deliberate and contemplative process of distinguishing between pieces of jinkō, sometimes as part of a game in which guests try to identify or match the wood being heated. Like the tea ceremony that developed in the same period, kōdō treats the appreciation of agarwood as a refined art with its own tools, etiquette and trained practitioners.

These traditions developed largely independently, yet they converge on similar associations: agarwood as something rare, sacred, or worthy of careful, ceremonial use. Each has its own guide: Islam, Buddhism, Hindu tradition, Chinese culture and Japanese culture.

A material worth understanding before you buy

Because genuine high grade agarwood is rare and expensive, its market has long attracted misrepresentation, from synthetic scenting passed off as natural resin to wood from common origins labelled as something rarer. None of that is a reason to avoid the material. It is a reason to understand it properly first.

This guide is a starting point. From here, the other hubs go deeper into where agarwood comes from, how grading and authenticity testing work, how it is used once you own it, and what to know before you buy. If you are close to a purchase, start with how to test agarwood authenticity at home.