Agarwood (Oud)

Agarwood is reputed to be the most expensive wood in the world. There are many names for the resinous, fragrant heartwood produced primarily by trees in the genus Aquilaria. Most commonly, the resin is known as agarwood, aloeswood, eaglewood, gaharu, agalocha or oudh (In Arabic).

Aquilaria crassna from freeland.org  Critically Endangered

“The ability of surviving trees to grow and reproduce is dramatically reduced”.

Agarwood has been used to make high quality incense since centuries. The Chinese describe its smell as “a sweet, deep but balanced fragrance” and use it in religious and festive celebrations, and so do Arabian, Indian and Japanese people. Agarwood is also part of many traditional pharmacopoeias, dating back to medieval times and Chinese doctors still prescribe it for colds and disgestion problem. Oil extracted from agarwood is used in Arabian countries as a perfume.

Agarwood is a resinous heartwood that occurs in trees belonging to the species of Aquilaria, Aetoxylon (A.symeatalum) and Gonystylus genus of Thymelaeceae family. However, species of the genus Aquilaria are mostly known for the production of agarwood – it’s a fast growing, evergreen tree.

Aquilaria crassna saplings. 4weeks after germination, 4inches tall

Agarwood or oudh forms as a reaction to fungal or bacterial attack. Trees, ocassionally become infected with a parasite mould secrete a fragrant, protective oil into wounded areas (roots, branches or sections of the trunk), which gradually become harder and dark brown to black. The heartwood (central part of a tree, which is darker in color than the sapwood) is relatively light and pale color before infection. Normally harvesters would cut only the infected parts in the hope that the tree would produce more of this resinous wood.

Aquilaria tree showing the infected darker part – agarwood

Aquilaria species that produce agarwood are found throughout Asia, while occur naturally in South and Southeast Asia. The Indian sub-continent was the main source of agarwood for many centuries but as trees became scarce in the middle of the twentieth century, extraction intensified in Indochina. Later on it was extended to Indonesia and Malaysia. Today Agarwood plantations exist in a number of countries, including Bangladesh, Bhutan, India, Laos, Myanmar, Papua New Guinea, Thailand and Vietnam.

Aquilaria with darker agarwood

It can grow on a wide range of soils, including poor sandy soil. Seedlings of most species establish best in shady, moist conditions, but large adult trees sometimes become emergent in the forest and can withstand full sun. Some species can be found growing on steep, rocky, exposed slopes, and in regions that experience a hot, dry season. The trees grow to 6-20 m tall.

The leaves are alternate, 5-11 cm long and 2-4 cm broad, with a short acuminate apex and an entire margin. The flowers are yellowish-green, produced in an umbel, the fruit is a woody capsule 2.5-3 cm long. At least fifteen species of Aquilaria trees are known to produce Agarwood.

Following are the species that produce agarwood: (Wikipedia)

Aquilaria khasiana, found in India
Aquilaria apiculina, found in Philippines
Aquilaria baillonil, found in Thailand and Cambodia
Aquilaria baneonsis, found in Vietnam
Aquilaria beccarain, found in Indonesia
Aquilaria brachyantha, found in Malaysia
Aquilaria crassna, found in Cambodia, Malaysia, Thailand, and Vietnam
Aquilaria cumingiana, found in Indonesia and Malaysia
Aquilaria filaria, found in China
Aquilaria grandiflora, found in China
Aquilaria hilata, found in Indonesia and Malaysia
Aquilaria malaccensis, found in Malaysia, Indonesia, Thailand, and India
Aquilaria microcapa, found in Indonesia and Malaysia
Aquilaria rostrata, found in Malaysia
Aquilaria sinensis, found in China
Aquilaria subintegra, found in Thailand

Aquillaria Malacenensis is considered to be the queen of Indonesian oudh. This tree can grow about 40 M or 131.23 ft in height with its diameter 80 cm. It is the best producer of agarwood resin and oil in Indonesia.

Agarwood is exported in various forms (wood chips, powder, oil and as finished products such as perfumes, incense and medicines), and the main importers are countries in the Middle and Far East – in particular the United Arab Emirates and Saudi Arabia (where agarwood is known as oudh), as well as Hong Kong, Taiwan and Japan.

EXTRACTION METHOD

There are three methods through which agarwood oil is distilled namely, hydro-distillation, steam distillation and super critical CO2 extraction. However, the most common methods of distillation are hydro-distillation and steam distillation. Another thing that has its mark on the distillation of the oil is the age of the tree. Older trees have a higher resin content and just like a wine, old resin gets better with age. Speaking of the grading of agarwood oil, the best quality oil comes out from first distillation and after this the wood undergoes for second distillation and hence, it is graded accordingly the number of times it is cooked.

Oil coming from steam distillation is said to lack the three-dimensional smoky quality which comes from hydro-distilled oil. In both methods, after the oil has been distilled, it is filtered, sunned, and aged for a while. The more the oil aged, the better it will smell.

When is it needed to develop synthetic substitutes?

Development of synthetic substitutes usually arises when sustainable supplies of the natural product are not available and are expensive at the same time. Since, Agarwood cannot be synthesized, chemical substitutes are already available for perfume these are cheap and constitute the least profitable end of the market. In addition, these products do not come even close in mimicking the natural product. The major chemical components responsible for the characteristic scent of Agarwood products, sesquiterpenes, can in principle be synthesized. However, these are very complicated structures that will be extremely expensive to synthesize, which makes it commercially completely unattractive.

So the major difference in fragrances of oudh oil and synthetic oudh can be distinguished easily. Oudh smells heavenly, woody and balsamic and surrounds a warm aura of bitter sweet and woody nuance. Whereas, synthetic oudh smells plain woody, leathry and lacks that warm balsmic aura.

WHY IS AGARWOOD EXPENSIVE?

Low yield from plant material, typical and labor intensive process of extraction. These are all very few reasons of high costing of Agarwood Oil. Low grade of resinous wood is used for oil production normally require minimum 20kg to produce 12ml of oil.

According to Nabeel Adam Ali, the director of Swiss Arabian Perfumes, the highest-quality oudh, once upon a time, came from trees older than 100 years. Having said that, it doesn’t mean that the new trees don’t get a good fragrance but what is missing is the quality, the heritage and the tradition. Still, sales of oudh-based perfumes continue to grow each year, but to meet the demand, many perfumers have started to using a blend of natural and synthetic oud. (New York Times)

Mr. Ajmal estimates that roughly 20 years ago, a kilogram, or 2.2 pounds, of high-quality “e-grade” oud — the entry-level grade among the best oud quality grades — would cost about 1,800 dirhams, or $500.

Now, that same amount would cost 12,000 dirhams, he said, a staggering increase in price. For those who are willing to spend as much as 200,000 dirhams per kilogram, the highest-quality oudh is still available. But Mr. Ajmal said that at that price, the profit margins are slim. (New York Times)

It has been estimated to be 18.000 euros for one kilo from the current market price.It is basically used in Natural Perfumery for long lasting and for increased weight in Natural Perfumes.

Another reason of agarwood being expensive is a threat to becoming endangered. The most important resin-producing species of Aquilaria are A. agollocha, A. malaccensis and A. crassna. A. malaccensis is protected worldwide under the CITES  (The Convention on International Trade in Endangered Species of Wild Fauna and Flora) convention as well as by the World Conservation Union, IUCN. A. crassna was listed as an endangered species few years back by the Vietnamese Government but is now listed as a protected species in Vietnam.

USES OF AGARWOOD

An important use of agarwood is the production of incense. Agarwood is an aphrodisiac, both in oil form, and as incense. These are generally topical uses but the oil is also sold in Vietnamese pharmacies for internal use with the same goal. Chinese medicine uses powdered Aquilaria as a treatment for cirrhosis of the liver and for other medicines. It has also been used as a treatment for lung and stomach tumors.

http://www.vnagar.org