Aquilaria Seeds | Agarwood
LATIN NAME: Aquilaria
COMMON NAME: Agarwood, Aloeswood
Plant Profile
Agarwood is not a species character so much as a reaction. Several Aquilaria species, evergreen trees of the rainforest understorey in South-East Asia and southern China, produce a dark, dense, fragrant wood only when the trunk is wounded and then colonised by fungi.
A healthy tree has pale, light, almost worthless timber. The resin forms in streaks and pockets around injury sites, and a tree may take eight to ten years to produce enough to harvest. The scent is sweet, woody and complex, and it is one of the most expensive raw materials in the perfume trade. Plantations in Vietnam, Laos and Hainan now supply most of the legal trade.
Science & Biotechnology
The wound response is a chemical defence. When the tree is damaged, either mechanically or by insects, fungi such as Lasiodiplodia theobromae enter the tissue and the tree deposits sesquiterpenes and chromones into the affected zone, which darkens and hardens the wood.
The main sesquiterpenes are agarospirol, jinkoh-eremol and alpha-guaiene, and the chromones give the wood its fixative quality. The process is slow and uneven, which is why natural agarwood varies so much between pieces. All Aquilaria species have been on CITES Appendix II since 2005, and exports require permits and a quota. Distillation yields an oil at well under one per cent of the wood, and the spent chips are still sold as incense, which is one reason the trade is hard to audit.
Uses & Benefits
Wood is burned as incense, distilled for oil, or worn as beads. In Chinese medicine the powdered resin is used at one to three grams for chest and abdominal pain, and it appears in a number of patent formulas.
The market has a serious substitution problem. Cultivated wood from inoculated plantations is now common and is legally traded, but it is often sold as wild. Natural pieces are dense enough to sink in water, hence the trade term sinking incense, and the price difference between sinking and floating grades is a factor of twenty or more. Small offcuts are often the best value for burning, since the resin is concentrated at the edges of the wound.
Growing from Seed
Agarwood seed is recalcitrant: it has no dormancy and dies within days if it dries. Sow it the day it is cleaned, in a shaded nursery bed, and expect germination in two to four weeks. Seedlings need shade for the first year and grow slowly.
Trees are planted at three by three metres and left for six years before the first inoculation. Producers then drill the trunk and insert a fungal culture, or wound it in a controlled pattern, and wait another two to four years. Without inoculation, a plantation tree may never produce resin at all.
Our Take
A tree that has to be injured before it becomes valuable, and a material where the paperwork tells you more than the smell does.
Related Reading
If Agarwood appeals to you, these related plants are worth a look: