Sandalwood is a semi-parasitic tree, deriving some of its nutrients from a host tree; stands of sandalwood can also provide environmental benefits. In the drier south-west of Western Australia, sandalwood (Santalum spicatum) and its hosts are native to the area and while offering a needed deep-rooted perennial to the landscape, add much sought-after biodiversity.
In the tropical north, the sandalwood species (S. album) is exotic but the hosts are generally native and together they can add a needed balance in an irrigated system threatened by salinity.
The value of the sandalwood tree is its heartwood, which is the inner core of the bole of the tree. As this core ‘dies’ within the sandalwood tree, it is filled with sesquiterpenes. These chemicals appear to protect the heart of the tree against fungi and insects but this process may just control water-balance or the proportion of live tissue the tree canopy has to sustain. A complex of up to one hundred of these sesquiterpenes make sandalwood oil and the scented wood for which the tree is known.
Sandalwood species differ in their sesquiterpene or oil profile and thus some species are more favoured than others. This choice is based on the amount of santalol and santalenes present and the lack of farnasyl, a sesquiterpene that is a skin irritant. In Australia there are two main species grown for sandalwood oil, S.album and S. spicatum. S. album is the most sought after as it has high levels of santalol and santalenes and no farnasyl.
World-wide, sandalwood oil has been used as a complex. The predictability of the S. album oil profile makes it popular in high-valued perfumes. S. spicatum has ventured into this market but needs constant manipulation controlling farnasyl levels. Other species are used but are not as highly valued. The waste timber after extraction is used to manufacture joss sticks, insect repellents, potpourri and marquetry. The highest valued product is a carving log of only heartwood.
Plantation establishment has been driven by the predicted value of the sandalwood product. Plantation maturation is expected to take at least 15 years for S. album and 25 years for S. spicatum. This estimated rotation length is based on the economic balance between heartwood production, product value and time. Scarcity and sandalwood oil demand has driven product prices upwards making this a highly attractive enterprise. The risk is predicting the impact of the spread of plantations in the Pacific Rim (including Western Australia) and China, as well as the accelerated development of substituting synthetics for the natural sandalwood oil.
Australia’s sandalwood industry has a long history by domestic standards. In fact, it is one of Western Australia’s first significant export industries, with shipments of S. spicatum to China in 1844 for use in the production of incense and funeral pyres. The Western Australian industry now commands around 40% of the international sandalwood market. This demand is met exclusively from natural ‘wild’ stands in Western Australia’s rangelands with approximately 2,500 tonnes being harvested annually for export to Asia, India and Europe.
Approximately 2,000 tons of this harvest is controlled by the State Government under licence arrangements to ensure sustainable wild harvest. Areas are selected where the harvest can occur and each tree ‘pulled’ is replaced with seed buried next to a host to optimise seed germination and the chance of a parasitic relationship. The seed-burying action substitutes for the loss of native fauna (usually Woylies) acting like squirrels.
Even with this human-intervention, the impacts of climate change and the popularity of indiscriminate grazing goats on pastoral leases, has led to limited regeneration. The remainder is harvested from private land or Aboriginal Lands Trust lands. Future supply will most likely be complemented by sandalwood sourced from public and private plantations, and individual farmers.
Sandalwood plantations are expanding in Western Australia. While still highly experimental, the tree is proving popular due to its high value and survival in the harsh environments of northern Australia and the south-west of Western Australia. Supported with managed-investment-scheme funding from the Federal government, a commercial S. album plantation has been established in the Ord region of Western Australia.
Even larger plantations have been established in the dry south-west with S. spicatum, mainly by farmers. Plantings of S. album have started in the tropical north of the Northern Territory and Queensland and another native species of sandalwood (S. lanceolatum) grows and is being further developed in Queensland.
Facts and figures
- Sandalwood value is in the production of bole heartwood which is filled with sesquiterpenes which make up the complex sandalwood oil
- Sandalwood has been used for religious and cultural purposes in Asia for centuries
- Sandalwood oil is used in perfumes, and beauty products, while the heartwood is used for carving and the waste produce for burning either as insect repellents or joss sticks
- Two species of sandalwood are native to Australia – S. spicatum in the south-west of Western Australia and S. lanceolatum in Queensland. S. album is regarded as an exotic, and grown in the north of Australia, mainly Kununurra
- The Australian sandalwood industry commands around 40% of world market share
Commercial production of sandalwood is currently based in Western Australia with some new plantations being developed in North Queensland and the Northern Territory. Trials have also been established in New South Wales, South Australia and Victoria.
Approximately 2,000 tonnes of S. spicatum was harvested from natural ‘wild’ stands in the Rangelands region of Western Australia. The 13,500 hectares of sandalwood under production on farms in the Western Australian wheatbelt lay the foundation for an alternative agricultural industry for many farmers. The plantings of sandalwood in Western Australia’s agricultural zone has increased steadily since 1999 with estimates that the estate is likely to reach 50,000 hectares by the year 2020.
Around 6,000 hectares of Indian sandalwood (S. album) have been established on irrigated land in the Ord River Irrigation Area in Western Australia, mainly funded by managed investment schemes. The first harvest was undertaken in 2012, and while under-age the heartwood was reported to be of good quality.
Plantations of Indian sandalwood are also planted in tropical north Queensland and in parts of the Northern Territory around Katherine. To date the species has been established and maintained on irrigation, defining its distribution.
Another native species of sandalwood, S. lanceolatum, grows in Queensland. It has not, as yet, been commercially developed as S. album is now being grown in the region. Wild harvest of S. lanceolatum from Crown lands in Queensland has remained at around 300 tonnes per annum over the last decade.
There are approximately 400ha of trial plantations of both S. spicatum and S. album in New South Wales, South Australia and Victoria.