Flower Inflorescences
(Copyright © Muhammad Alif Azyraf)Aquilaria hirta is a tree species in the family Thymelaeaceae, locally known as ‘Karas’ or ‘Chandan bulu’ (Hassan et al., 2011). It occurs on the hill slopes of tropical lowland forests (Soehartono, 1999). The tree can reach up to 14 m in height, and the bark is whitish and rather smooth. The leaves are elliptic-oblong or ovate-oblong, measuring 6.5–14 cm by 2.5–5.5 cm. The leaf base is acute or cuneate, whereas the leaf tip is attenuate or acuminate (Azhari et al., 2014). The flowers are white or light yellow, and the fruit is slender and pear-shaped, measuring 3.5 cm by 1 cm (Pern et al., 2018).
Aquilaria hirta is one of the main sources of agarwood, also known as ’gaharu’, in Peninsular Malaysia. Agarwood is produced through a pathological process triggered by fungal infection or chemical stimulation (Elias et al.,2017). Agarwood is a highly valued fragrant wood used for incense, perfume and traditional medicines (Soehartono & Newton, 2000). It has a distinct, deep aroma that is both rich and unique. The smell of the wood may not be very strong at room temperature, but it gets stronger when it burns. The Japanese and Arabs use the essence in their incense items and like the strong scent. According to Persistence Market Research (2019) and Ash (2020), sales of agarwood chips alone reached USD 30–32 billion globally in 2018 and are expected to reach USD 64 billion by 2029.
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species lists A. hirta as Vulnerable (VU) (Harvey-Brown, 2018). Tree exploitation has increased over the years due to rising customer demand for fragrance, cosmetic, medical and religious businesses that employ wood and essential oils of agarwood. The depletion of natural resources is driving up the cost of agarwood (Mohd-Shafik et al., 2020). Since 2004, trade in Aquilaria species has been regulated by including the species in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES, 2017). Importers and range states must strictly regulate the use of the species and obtain permission for exports. This restriction helps protect the remaining wild population and requires global buyer cooperation (Thompson et al., 2022).
