Aquilaria crassna is a big tree that can reach 30 meters in height. The diameter of the trank varies from 0.6 to 0.9 m. The bark is greyish brown. The leaves are ovate oblong and oval. Their length varies from 5 to 11 cm in width. The edges are hair. The flowers are small and pale yellow. The calyx is bell-shaped. The flower about 4 cm long and 3 cm in diameter.
Aquilaria crassna 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.
Exploitation of the diseased wood for the perfume industry has resulted in population declines in Vietnam exceeding 80% over recent years. There is a strong indication that the same losses are occurring in the rest of Indo-China. Based mainly on the situation in Vietnam, this species is classified as ‘Critically Endangered’ in the IUCN Red List of Threatened Species(2011)