Agarwood
Aquilaria crassna Pierre ex Lecomte
Agarwood is resinous, fragrant wood formed when Aquilaria trees are wounded and secrete resin as a defence. It is among the most prized fragrance materials in the world.
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Gallery
Aquilaria crassna in Chiang MaiAgarwood tree (Aquilaria crassna)
Aquilaria crassna in a botanical garden
Aquilaria crassna canopy
Aquilaria crassna in Mu Ko Lanta National ParkAquilaria crassna in Chiang MaiAgarwood tree (Aquilaria crassna)Overview
Aquilaria crassna is a medium-sized evergreen tree, 15–25 m tall with a 40–50 cm trunk diameter, in the Thymelaeaceae family. Its native range is Indochina — Vietnam, Laos, Cambodia, Thailand and Myanmar — according to Kew's Plants of the World Online. Vietnam hosts five native Aquilaria species, and agarwood from A. crassna is widely regarded by experts as among the finest in the world.
Trees begin flowering at 6–8 years old, with flowers opening in March–April and fruit ripening that same June–July. Agarwood is light-demanding: it regenerates under canopy but needs gaps to keep growing. Once found across Vietnam, it now survives scattered in Ha Tinh, the Central Highlands and Phu Quoc Island; households in Ha Tinh have collected seedlings for home gardens since 1986.
The miracle of agarwood lies in its wound-defence mechanism: only about 2–10% of wild trees ever form resin. Resinogenesis starts with mechanical wounds or infection by the fungus Phaeoacremonium parasitica, prompting the tree to seal the damage with fragrant resin; decades of accumulation are needed before the wood develops a deep scent. Connoisseurs grade it dó → trầm → kynam, the top grade being dense enough to sink in water.
Chemically, a survey of 367 compounds from the four main agarwood-producing Aquilaria species (Gao et al., RSC Advances, 2019) shows two dominant groups: 2-(2-phenylethyl)chromones and derivatives (≈57%) and sesquiterpenes (≈35). From A. crassna specifically, new chromone dimers such as crassin A–D and aquilacrassnin A–F have been isolated, showing in-vitro cytotoxic activity against BEL-7402 cancer cells (Fitoterapia, 2019).
Economy and conservation are inseparable. In 1990 one kilogram of agarwood cost USD 800–1,000; by 2020 the global agarwood market was estimated at about USD 32 billion. CITES trade data for 1996–2015 recorded 141,149 kg of powder, 93,080 kg of chips and roughly 4 million live agarwood trees exported worldwide, mostly from artificially propagated sources. Vietnam now has over 10,000 ha of A. crassna on Phu Quoc and in Khanh Hoa, plus inoculation facilities using microbial-culture technology, gradually easing pressure on natural forests.
Life cycle
From seed to productSeed & germination
Aquilaria seeds germinate under a humid forest canopy; seedlings need shade and high moisture to survive.
Sapling
The sapling grows slowly with a slim, shade-loving stem and takes years to mature enough to form resin.
Mature tree
After 15–25 years the tree reaches 15–25 m; its trunk is then thick enough for fungi and bacteria to enter wounds.
Resin formation
When wounded, the tree secretes resin to seal the wound; 10–50 years of accumulation turn it into precious agarwood.
Harvest & distillation
Agarwood is taken from the trunk and steam-distilled into oud oil, or crafted into incense and jewellery.
Distribution & origin
Share of recorded occurrences by region- Vietnam40%
- Laos18%
- Cambodia16%
- Thailand14%
- Myanmar7%
- Other areas5%
Chemical composition
Relative content in agarwood resin- Chromone2-(2-phenylethyl)chromones and dimers — dominant group (≈57%)55%
- SesquiterpeneAgarofurans, eudesmanes, guaianes — warm woody notes (≈57%→35%)35%
- AgarospirolCharacteristic balsamic note5%
- BenzylacetoneSweet light note3%
- OthersTrace flavonoids and phenolics (leaves, wood)2%
Uses
- Distilled into oud oil for luxury perfumery
- Incense and ceremonial burning
- Beads, jewellery and fine craftwork
- Traditional medicine as a sedative and qi-regulating remedy
- Pharmacological research: in-vitro cytotoxic compounds (Fitoterapia 2019; ACS Omega 2023)
- Export of powder, chips and seedlings under CITES permits
Properties
- Colour
- Black-brown, oily grain
- Scent
- Sweet, warm-woody, smoky
- Density
- 0.98 – 1.10 g/cm³
- Distillation
- Steam, 100–120°C
Habitat & conservation
Tropical evergreen rainforest on well-drained sandy-basaltic soils at 300–900 m. Adult trees are light-demanding; regeneration succeeds under canopy but needs gaps. In Vietnam it survives scattered in Ha Tinh, the Central Highlands and Phu Quoc Island.
Conservation
Aquilaria crassna is listed as Critically Endangered (CR, criterion A1cd, 2018 assessment) on the IUCN Red List and in CITES Appendix II. International trade 1996–2015 covered 141,149 kg of powder, 93,080 kg of chips and about 4 million live plants, mostly artificially propagated. In Vietnam the species is conserved through protected forests, a breeding orchard (Vietnam Tree Seed Project) and over 10,000 ha of plantations on Phu Quoc and in Khanh Hoa. Agarwood exports are regulated under CITES (Decree 06/2019/NĐ-CP, Circular 26/2025/TT-BNNMT).
References
- 1IUCN Red List — Aquilaria crassna — IUCN, 2024
- 2CITES Appendix II — Aquilaria spp. — CITES, 2023
- 3Chemical constituents of agarwood — Journal of Natural Products, 2021
- 4Bảo tồn trầm hương Việt Nam — Institute of Ecology and Biological Resources, 2020
- 5Aquilaria crassna — IUCN Red List assessment (e.T32814A2824513) — IUCN, 2018
- 6Aquilaria crassna Pierre ex Lecomte — Plants of the World Online — Kew Gardens, 2026
- 7Overview of sesquiterpenes and chromones of agarwood originating from four main species of the genus Aquilaria — RSC Advances, 2019
- 8Dimeric 2-(2-phenylethyl)chromones from the agarwood of Aquilaria crassna in Laos — Fitoterapia, 2019
- 9Conservation and use of Aquilaria crassna in Vietnam — a case study — FAO, 1997