Aquilaria crassna (no local name as CITES prevent this for trade outside from the original habitat) is an evergreen tree with an open crown; usually growing 15 – 20 metres tall but with exceptional specimens to 30 metres. The bole is 40 – 60cm in diameter, exceptionally to 100cm.
The aromatic resin obtained from this tree is one of the most famous and most expensive on the planet. It has a very long history of use in religious ceremonies, at funerals etc in the Orient and is widely sought after as an ingredient in perfumery. Commonly harvested from the wild, it is also to some extent cultivated; it is frequently planted around temples, houses and home gardens, whilst large scale industrial plantations have been initiated in Vietnam.
Scattered in primary and secondary forests on rocky, shallow ferralitic soil, often along the sides of streams, at elevations up to 1,000 metres in Thailand, Cambodia, Laos and Vietnam.