Incense trees (Aquilaria sinensis) in Hong Kong- Protecting a culturally important species

Aquilaria sinensis is native to the subtropical regions of southern China, including Guangdong, Guangxi, Fujian and Hainan province and Hong Kong^[1]. It thrives in humid, well-drained forests, often growing at elevations up to 1,000 meters and reaching ~20 meters in height. As a forest giant it stabilises the ecosystem, providing food and shelter for different animals and plants.

Historically, A. sinensis was found across the forests of southern China. Today the New Territories and outlying islands of Hong Kong remain its largest strongholds^[2]. However, habitat loss from urbanization and deforestation have drastically reduced populations. Wild trees are now increasingly rare and are protected by the Agriculture, Fisheries and Conservation Department (of the Hong Kong government, AFCD) under multiple Hong Kong laws (Cap.86, Cap.208A, Cap.210, Cap.586).

Uses

The primary significance of Aquilaria species stems from its ability to produce agarwood—a dark, aromatic resin that forms within the heartwood of the tree in response to injury, infection, or stress. While healthy trees produce little to no resin, when wounded, the tree's defence mechanism results in the formation of agarwood. This resin is highly valuable due to its complex fragrance, which has made it a highly traded commodity for thousands of years.

Agarwood is used predominantly in:

• Perfumery: Its rich, woody, and sweet scent makes it a premium ingredient in luxury perfumes and incense^[3].

• Traditional Chinese Medicine: Agarwood is believed to have therapeutic properties, including alleviating pain, promoting relaxation, and improving circulation^[4].

• Religious and cultural ceremonies: Incense made from agarwood is used in temples, spiritual rituals, and offerings across Asia due to its calming aroma and spiritual significance^[5].

• Luxury goods and collectibles: The rarity and desirability of high-quality agarwood have made it a status symbol, with some pieces fetching astronomical prices³.

• The value of agarwood depends on several factors, including the age of the tree, the quality and quantity of resin, and the processing method. Due to its high demand and limited supply, A. sinensis and other incense tree species have become targets for overharvesting and illegal trade.

  
  

Poaching and trade

Hong Kong (香港, hoeng1 gong2) translates to 'Fragrant Harbour,' a name originating from the islands’ historical role as a trading hub for incense tree aromatic goods^[6]. Hong Kong has been coined a wildlife trade ‘hub’ due to the city’s strategic position on global trade routes facilitated the import and export of raw and processed wildlife trade products^[7], including agarwood. Although much of the trade of agarwood is now regulated through CITES, Hong Kong remains an important centre for the trading, processing, and distribution of agarwood and its derivatives^[8].

The city’s markets feature a wide range of agarwood products—from raw chips to finished incense—serving both domestic consumers and international buyers.

However, Hong Kong is also a significant conduit for illegal agarwood trade. Despite the law and trade regulations, poaching of wild A. sinensis trees and illegal smuggling of agarwood products persist and has even increased in recent years^[9]. The high market value of agarwood makes it a lucrative black-market commodity, fuelling illegal trade networks. From 2005 to 2018, 730 poaching cases, 1463 injured trees and ~1325 kg of agarwood were confiscated^[10]. These illegal activities threaten the survival of wild populations as trees often die if large portions are cut from them.

(A) Cage protections around incense trees on Lamma Island, New Territories, Hong Kong.

(B) An incense tree in Hong Kong which has had sections poached for the illegal trade (discovered summer 2025).

In response to poaching, Hong Kong authorities have:

1. Updated the Species Action Plan for A. sinensis.

2. Included Hong Kong’s incense trees in the Hong Kong Biodiversity Strategy and Action Plan (BSAP) (https://www.afcd.gov.hk/english/conservation/Con_hkbsap/bsap2016/bsap2016.html).

3. Increased enforcement efforts, including customs inspections, seizures of illegal shipments, and stricter licensing for legal harvest and trade.

4. Provided funding for our anti-poaching research!

   
   

Anti-poaching research at HKU

In 2026, funded by AFCD, a new project commenced at The University of Hong Kong to aid the government with prosecuting criminals poaching and trafficking agarwood.

The team, members of the Conservation Forensics Laboratory (https://www.conservationforensics.com/), have worked with AFCD for multiple years to establish a genetic tool for individual and geographical identification. The team is additionally turning their attention to supplementary tool types which we will be developing over the next 3 years.

This tool will be a water-based solution with an invisible signature. If poached and intercepted by Hong Kong officials, tree parts with this signature will be easily identified from other populations of A. sinensis and traffickers will be prosecuted. This tool will be reliable and tests to confirm the signature are very fast – <48 hours!

Read our next blog to find out more about the tool- what it is and how we are using it!

^[1] Hong Kong Herbarium: https://www.herbarium.gov.hk/en/publications/books/book2/text/aquilaria-sinensis/index.html 

^[2] AFCD. (2023). Incense Tree (Aquilaria sinensis) Species Action Plan 2023-2027. Hong Kong.

^[3] Barden, A., Anak, N. A., Mulliken, T., & Song, M. (2000). Heart of the matter: agarwood use and trade and CITES implementation for Aquilaria malaccensis. Traffic International, Cambridge, UK, 17-18.

^[4] Tan, X., Wang, L., Smith, W. K., Sun, H., Long, L., Mao, L., ... & Zhong, Z. (2023). Aquilaria sinensis leaf tea affects the immune system and increases sleep in zebrafish. Frontiers in Pharmacology, 14, 1246761.

^[5] López-Sampson, A., & Page, T. (2018). History of use and trade of agarwood. Economic botany, 72(1), 107-129.

^[6] Wei, P. T. I. (2014). Why is Hong Kong called 'Fragrant Harbour': A synthesis. Journal of the Royal Asiatic Society Hong Kong Branch, 54, 33-57.

^[7] Andersson, A.A., Tilley, H.B., Lau, W., Dudgeon, D., Bonebrake, T.C., & Dingle, C. (2021). CITES and beyond: Illuminating 20 years of global, legal wildlife trade. Global Ecology and Conservation, 26, e01455.

^[8] Xie, Z. Q., Xu, J. Y., Rafiq, M., & Cheng, C. S. (2024). An analysis of Agarwood trade patterns, historical perspectives, and species identification challenges: repercussions for importing nations. TMR Mod. Herb. Med, 7(1), 1.

^[9] Jim, C. Y. (2015). Cross-border itinerant poaching of agarwood in Hong Kong's peri-urban forests. Urban Forestry & Urban Greening, 14(2), 420-431.

^[10] Chen, Y., Liu, H., Heinen, J. (2019). Challenges in the conservation of an over-harvested plant species with high socioeconomic values. Sustainability, 11(15), 4194.