Safeguarding sandalwood: A review of current and emerging tools to support sustainable and legal forestry

Societal Impact Statement: Sandalwood and other high value tree species are under significant threat from illegal harvest. Illegal logging is an increasing problem contributing to deforestation, biodiversity loss, human rights abuses and funding transnational crime. Successful prosecution of illegal logging is hindered by a lack of methods to provide evidence of the origin of timber. New analytical techniques have been developed to trace timber back to its source. These methods, together with the establishment of sustainable sources of forest resources, can help protect vulnerable species by providing evidence to prosecute illegal harvest and ensure that commercially available forest products come from sustainable sources. Summary: Sandalwood is highly valued for its fragrant oil and has a long history of cultural and economic importance in many regions of the world. Historical overharvest and poor management have depleted natural populations of sandalwood, which are slow to regenerate. The increasing establishment of plantation sandalwood creates an alternative resource for the sandalwood industry while potentially relieving harvesting pressure on natural stands. Due to the high demand for sandalwood, remaining wild populations are still under threat from illegal logging and methods to identify the source of harvested sandalwood are needed. Laws and regulations aimed at preventing illegal harvest and possession of sandalwood have been put in place but cannot be enforced without the forensic tools to independently verify claimed origin or product quality. The high value of sandalwood combined with the difficulties in enforcing illegal logging laws makes these species particularly vulnerable to poaching. There is an immediate need to develop tools that can identify illegally sourced and adulterated sandalwood products. This paper reviews the current and developing scientific tools that can help identify and control illegal activity in sandalwood supply chains and provides recommendations for future research. Topics include isotope and DNA analysis for tracing illegally harvested sandalwood, chemical profiling for quality control of sandalwood oils, network and policy development to establish a framework for future regulation of the sandalwood trade

Agarwood resin production and resin quality of Gyrinops walla Gaertn

Agarwood is a resin produced by certain species of family Thymalaeaceae due to a self-defence mechanism. Most species of Aquilaria and a few species of Gyrinops, Aetoxylon and Gonystylus are capable of producing agarwood. Gyrinops walla, a member of the family Thymalaeceae is recorded only in the wet zone of Sri Lanka and very rarely in southwest India, has not been previously studied to identify its ability of producing agarwood. Therefore the present study was the first ever to conduct and identify the production of agarwood in G. walla and the quality of its resins. Six G. walla trees growing in two distinctive areas of the wet zone of Sri Lanka were used for the present study. All six trees had natural wounds occurred sometime before the sample collection due to abrasions or fallen branches. The dark coloured tissues of the affected areas were carefully collected without cutting the trees and resins were extracted by solvent extraction method. The extracted resins were analysed using gas chromatography to identify the different compounds. Finally these compounds were compared with that of selected Aquilaria species. The results revealed a strong similarity of resin compounds of G. walla with that of Aquilaria species which are commercially used to collect agarwood. Further studies should be conducted to identify the effects of artificial resin induction methods on G. walla that are already used on Aquilaria species

Characterisation and variation of agarwood resins from Gyrinops walla

The genera Aquilaria and Gyrinops of Thymalaeaceae family produce agarwood as a response to damage to their xylem tissues. Agarwood is used for perfumery, incense and traditional medicine. Gyrinops walla is the only agarwood producing species naturally growing in Sri Lanka and it is often harvested illegally from the wild. Research on characteristics of the G. walla resin is limited and insufficient to support its development as an agroforestry crop. The present study sampled a total of 90 G. walla trees from nine natural populations distributed in four agro-ecological zones in Sri Lanka. Resinous tissues were collected and resin contents were solvent extracted. Yields varied from 0.1 to 9.8% with no significant difference between the populations. GC-MS analysis of the G. walla resin identified 21 constituents; agarospirol, d-selinene, alloaromadendrene oxide, spathulenol, and two unidentified 2-(2-phenylethyl)chromone derivatives were found to be common for all tested populations. The chemical composition of G. walla resins was comparable with commercially available agarwood resin of Aquilaria species. The average amount of agarospirol varied from 1.13 to 7.16%. Significant correlations were not found between resin contents and tree diameter or height. Resin characteristics showed no significant difference between the populations. However, variations were observed among trees of the same population