Tapping the wealth of our woods

Malaysian Business, Dec 1, 2007 by The Forestry Department

GAHARU is the resinous heartwood from Aquilaria trees, which are large evergreens native to South and Southeast Asia. However, not all of these trees will produce Gaharu. In this connection, one of the many theories states that the trees occasionally become infected with fungus and begin to produce an aromatic oleoresin in response to this attack. As the fungus grows, the tree produces a very rich, dark resin within the heartwood, possibly as a defence measure to contain the pathogen. It is this precious resinous wood that is treasured around the world.

The resin is known by many names and is valued in many cultures for its distinctive fragrance and it is used traditionally for incense and perfumes. Gaharu is known as Chn-xiang in Chinese and Jinkoh in Japanese, both meaning "sinking incense", and alluding to its high density. Both Gaharu and its resin distillate and extracts are known as Oud in Arabic. In Europe it was referred to as Lignum Aquila or Agilawood, presumably because of its appearance. In Indonesia and Malaysia it is called Gaharu. Other than these, it is known as ghara In New Guinea, Trm Hng in Vietnamese, Kalambak in Cambodian, Gridsanah in Thai, Agar in Hindi and Mai Ketsana in Laos. The wealth of names for this dark and heavy wood reflects its worth, widespread and varied use over thousands of years.

DISTRIBUTION OF AQUILARIA SPECIES

There are altogether 25 known species of Aquilaria trees and they grow widely in south and southeast Asia. Out of these, five species of Aquilaria are found in Malaysia, namely Aquilaria hirta, Aquilaria malaccensis, Aquilaria beccariana, Aquilaria microcarpa and Aquilaria rostrata. A number of research studies have been conducted on Aquilaria malaccensis but little or none on the remaining four Aquilaria species.

In Peninsular Malaysia, the existence and distribution of Aquilaria trees were captured through the various inventories that have been carried out periodically. Based on the results of the Fourth National Forest Inventory that were carried out from 2002 to 2004, it has been estimated that there was a total of 3.55 million Aquilaria trees with a total volume of 1.79 million cubic meters in the natural forests. Out of the 3.55 million trees, almost 95% are having a diameter at breast height ranging from 15 cm to 45 cm.

HOW IS GAHARU FORMED?

There are many theories on how the Gaharu is formed in Aquilaria trees. There exist at least three hypotheses regarding its formation. One school of thought thinks that it is due to wounding, another says that it is due to both wounding and pathological processes while the third stipulates that it is due to wounding and both pathological and non-pathological processes.

Many studies have been carried out. Unfortunately so far there is no conclusive evidence for any of these theories or hypotheses. A study commissioned by TRAFFIC, the wildlife trade monitoring network, has appropriately summarised that, "the ecological interaction between the host tree and the wound and/or the fungi in order to produce agarwood (Gaharu) is poorly understood. Other factors such as the age of the tree, differences in the tree caused by seasonal variation, environmental variation and genetic variation of Aquilaria spp. may also play an important role in agarwood (Gaharu) formation".

Nevertheless, some studies have shown that the tree's resin production is in response to fungal infection while others, for example the studies by Tropical Rainforest Project, indicated that it is in response to wounding. The latter studies have further indicated that fungal infection can increase resin yield as a host response to contain damage due to fungal growth. Based on research work carried out so far, it is known that Aquilaria trees are naturally infected by a wide variety of fungi. These include species of Aspergillus, Diplodia, Fusarium, Penicillium and Pythium.

ECONOMIC VALUE OF GAHARU

Malaysia has a long history in the trade in Gaharu. In this regard, Gaharu wood has long been collected from the wild by the indigenous peoples of the interior of Peninsular Malaysia to supplement their income. In addition, other local people are also involved in collecting, particularly in the States of Kelantan, Pahang and Perak.

The economic value of first-grade Gaharu is extremely high. A whole range of grades and related products in the market varies with geographical location and cultural deposition. Their prices range from less than US$10 (RM33.40) per kilogram for the lowest quality to over US$30,000 (RM100,160) for top quality oil and resinous wood.

This scenario is similar in Malaysia. The grades differ and prices are often based on the views of collectors, the middle-men and the traders. However, as a rule of thumb, the prices of Gaharu for the various grades range from RM3,000/kg to RM25,000/kg as illustrated in Table 1.

In terms of trade, the market and demand for Gaharu is big. Between 2000 and 2006, Malaysia has exported a total of 1.3 million kg of Gaharu wood and chips. The details on the annual export of Gaharu wood and chips are as in Table 2.