Popularly known as ‘black gold of the forest’, gaharu is the resinous heartwood derived from the Aquilaria tree, one of the rarest and most precious plant species on Earth. Because of its rarity, the Aquilaria, or agarwood  tree as it is more commonly known, is one of the world’s most protected plant species whose harvest is universally controlled by CITES (Convention on International Trade in Endangered Species of wild Flora and Fauna). When this tree is attacked or injured either naturally or artificially, it becomes infected with mold and responds by producing an aromatic resin which gradually solidifies and eventually hardens. This is the basis of gaharu, which is harvested when the tree is felled. 

Uncontrolled harvesting of agarwood trees over the centuries and the depletion of the wild resource has caused its relative rarity and high cost. Thus the formation of CITES, a UN secretariat that oversees and whose aim is to ensure that international trade in specimens of wild animals and plants does not threaten their survival. A state for which the Convention has entered into force is called a Party to CITES and currently, there are 175 Parties, including Malaysia. 

In Malay, the agarwood tree is known as karas or depu. Today, it is being planted as a plantation crop. When the trees mature, they are inoculated with enzymes and treated with various methods over a period of  three months to two years to induce the formation of the gaharu resin before being harvested. 

Gaharu  relieves flatulence, acts as a diuretic and has aphrodisiac properties. It is also used as an ingredient in the treatment of smallpox, bronchial and respiratory problems, abdominal cramps, diarrhea, nausea, vomiting, old-age fatigue and pregnancy and post-partum illnesses. When used in aromatherapy, the scent of gaharu expels negative energy and promotes mental alertness. Valerian, a natural component of gaharu resin, relieves insomnia and calms the nervous system, allowing one to have a deeper longer sleep.

Traded and used for over 3000 years, gaharu is valued in many cultures for its distinctive fragrance. Gaharu and its derivatives have been traditionally used for incense and perfumes, in aromatherapy and culinary. It has gained great cultural and religious significance worldwide since ancient civilizations. Its oil is used as a base in some of the world’s most exclusive perfumes and research has also found its extracts and distilled water to contain high medicinal value. In certain Asian cultures, gaharu plays a role in the indication of social standing.

Agarwood comes under many names in different cultures. In Malaysia and Indonesia it is called gaharu. The Middle-East countries refer to its resin and extracts as Oud. It is known as ‘Mai Kritsana’ and ‘Mai Ketsana’ in Thailand and Laos respectively.The Chinese calls it ‘Chen-xiang’ and in Vietnam it is referred to as ‘Tram-huong’. Tibetans and Bhutanese call it ‘Agaru’ and in India it is known as ‘Agar’ and ‘Ogoru’. Papuans  call it ‘Ghara’ and Europeans refer to it as Eaglewood or Agilawood. In Japan ,it is known as Jin-koh.

There are over twenty-five species in the Aquilaria genus but not all produce the gaharu resin. The commonly-known species found in the South-East Asian region are: